A system is provided for use with circuit layout design data having a set of differential pairs and a set of bond wire pairs. A layout portion can receive the circuit layout design data. A crosstalk calculating portion can determine a first amount of crosstalk in a circuit corresponding to the circuit layout design data. A modifier can modify the circuit layout design data into modified circuit layout design data such that one of the set of differential pairs and the set of bond wire pairs includes a crossover. The crosstalk calculating portion can further determine a second amount of crosstalk in a circuit corresponding to the modified circuit layout design data. An optimizer can compare the first amount of crosstalk with the second amount of crosstalk to generate optimized circuit layout design data. A layout designer can output the optimized circuit layout design data.

The operating speeds of semiconductor devices have continued to increase and continuously push the limit of conventional packaging technology.
To support the ever increasing operation speed of semiconductor devices, a differential pair is often used. A differential pair is a pair of conductors used for differential signaling. A differential pair reduces crosstalk and electromagnetic interference and can provide constant and/or known characteristic impedance. Furthermore, a differential pair enables impedance matching techniques used for high-speed signal transmission lines. Non-limiting examples of a differential pair include twisted-pair, microstrip and stripline.
A differential pair reduces the total current between the two conductors of the differential pair, as Kirchhoffs Law predicts the total current as being zero through a cross section of the differential pair. The condition for emitting zero electromagnetic interference representing zero crosstalk is for zero total current through the cross section of the differential pair. However, in real world situations, zero current is not achieved, resulting in crosstalk between the conductors of a differential pair.
Additionally, crosstalk may occur between differential pairs as a result of second-order effects due to the finite impedance of the current source and impedance mismatch between the devices. For this case, the two conductors of the differential pair may be considered as a dipole with coupling on the order of l/r2 or l/r4, where r is the distance between lines of differential pairs. To reduce crosstalk, the effects associated with second-order effects need to be reduced.
The differential to differential pair crosstalk in electronic equipment limits its applicability to higher than 5 GHz types of Serializer/Deserializer (Serdes) designs. The crosstalk between differential pairs needs to be kept to a level of around −60 dB or less in order to minimize its impact on the channels ability to receive a greatly attenuated signal.
Modem signal channels at high speed can introduce an attenuation of 40 dB or more. To properly receive such a signal in the presence of a fully duplexed communication stream, a cross-coupling immunity of 60 dB is needed for reliable signal reception.
The crosstalk between differential pairs can be calculated.
In order to determine the crosstalk between differential pairs, the mutual inductance is calculated. The mutual inductance by a filamentary circuit i on another filamentary (consisting of wires and rods) circuit is given by the double integral Neumann formula as give by Equation 1 below:
                              M          ij                =                                            μ              0                                                      4                                                                                π                                                                                ∮                              C                i                                                                                ∮                                  C                  j                                                                                ds                    i                                    ·                                      ds                    j                                                                                                          R                    ij                                                                                                                    (        1        )
Where μ0 denotes the magnetic constant (4π×10−7 H/m), Ci and Cj are the curves spanned by the wires, Rij is the distance between two points.
The currents associated with the positive and negative conductors of a differential have the same magnitude of current but traversing in opposing directions.
Differential pair to differential pair crosstalk is a technology limiter that causes system failure in the form of signal detection error—increasing the system jitter and causing the signal detection eye pattern to close. An eye pattern, also known as an eye diagram, is a presentation (e.g. oscilloscope display) of a digital data signal as received at a receiver. Furthermore, the received signal is repetitively sampled and applied to the vertical input, while the data rate is used to trigger the horizontal sweep.
Reduction of this crosstalk is possible using a technique known as orthogonal crossovers. The use of crossovers between differential pairs introduces significant discontinuities in the transmission lines that make up the differential pairs. A significant source of the discontinuities are a result of the vias that are used to move the pair from one side to the other. A via in an integrated circuit or printed circuit board is a mechanism for transferring a signal from one signal layer to another signal layer.
Alternate methods used to reduce the reflections from the crossovers include designing the via structure in such a way as to match the characteristic impedance of the line.
FIGS. 1A-C illustrates an example conventional transmission line system 100.
Transmission line system 100 includes a differential pair 102 and a differential pair 104.
Non-limiting examples of a differential pair include twisted-pair, microstrip and stripline. Differential pairs 102 and 104 provide a transmission medium for transferring an electrical signal. A differential pair reduces crosstalk and electromagnetic interference and can provide constant and/or known characteristic impedance. Furthermore, a differential pair enables impedance matching techniques used for high-speed signal transmission lines.
Differential pair 102 includes a positive signal trace 106 and a negative signal trace 108. Differential pair 104 includes a positive signal trace 110 and a negative signal trace 112. In some embodiments, the positive signal associated with positive signal trace 106 is equal and opposite to the negative signal associated with negative signal trace 108. In other embodiments, the positive signal associated with positive signal trace 106 is different in magnitude to the negative signal associated with negative signal trace 108. In theory, for embodiments with equal but opposite signals associated with positive signal trace 106 and negative signal trace 108, the radiant electromagnetic field generated by the positive signal in positive signal trace 106 is cancelled by the equal and opposite radiant electromagnetic field generated by the negative signal in negative signal trace 108. Similarly, for some embodiments, the positive signal in positive signal trace 110 is equal and opposite to the negative signal in negative signal trace 112. In theory, radiant electromagnetic field generated by the positive signal in positive signal trace 110 is cancelled by the equal and opposite radiant electromagnetic field generated by the negative signal in negative signal trace 112.
The radiant effects of current through a differential pair may negatively affect the signals in an adjacent (or nearby) differential pair. In particular, a current traveling through one signal trace (or path) may affect the current traveling through another signal trace, wherein the magnitude is a function of distance. For example, current traveling through positive signal trace 106 will affect current traveling through positive signal trace 110, and will also affect current traveling through negative signal trace 112, but by a slightly less amount. Further, current traveling through negative signal trace 108 will affect current traveling through positive signal trace 110, and will also affect current traveling through negative signal trace 112, but by a slightly less amount. The overall effect is known as crosstalk interference, or crosstalk.
The total effects of crosstalk may be determined by integrating the effect along a length of the crosstalk, in this instance a length 114 noted as L. To simplify the discussion, first consider the effects of positive signal trace 106 and negative signal trace 108 on positive signal trace 110. Then, consider the effects of positive signal trace 106 and negative signal trace 108 on negative signal trace 112. This will be further described with reference to FIGS. 1B-C.
FIG. 1B takes into account the effects of currents of positive signal trace 106 and negative signal trace 108, as felt by positive signal trace 110. In this example, negative signal trace 108 and is separated from positive signal trace 110 by a distance 116 noted as r1, whereas positive signal trace 106 and is separated from positive signal trace 110 by a distance 118 noted as r2. The radiant effects of currents of positive signal trace 106, as felt by positive signal trace 110, are opposite to the radiant effects of currents of negative signal trace 108, as felt by positive signal trace 110. However, distance 116 is smaller than distance 118. Accordingly, the radiant effects of currents of negative signal trace 108, as felt by positive signal trace 110 are greater than the radiant effects of currents of positive signal trace 106.
FIG. 1C takes into account the effects of currents of positive signal trace 106 and negative signal trace 108, as felt by negative signal trace 112. In this example, negative signal trace 108 and is separated from negative signal trace 112 by distance 118 (again noted as r2), whereas positive signal trace 106 and is separated from negative signal trace 112 by a distance 120 noted as r3. The radiant effects of currents of positive signal trace 106, as felt by negative signal trace 112, are opposite to the radiant effects of currents of negative signal trace 108, as felt by negative signal trace 112. However, distance 118 is smaller than distance 120. Accordingly, the radiant effects of currents of negative signal trace 108, as felt by negative signal trace 112 are greater than the radiant effects of currents of positive signal trace 106 as felt by negative signal trace 112.
Comparing the situations illustrated in FIGS. 1B-C, it is clear that the radiant effects of currents of positive signal trace 106 as felt by positive signal trace 110 (as shown in FIG. 1B) is equal and opposite to the radiant effects of currents of negative signal trace 108 as felt by negative signal trace 112 (as shown in FIG. 1C). Accordingly, the radiant effects effectively cancel.
The remaining radiant effects are therefore drawn to the radiant effect of current of negative signal trace 108 as felt by positive signal trace 110 (as shown in FIG. 1B) in addition to the radiant effect of current of positive signal trace 106 as felt by negative signal trace 112 (as shown in FIG. 1C). Ideally, the current in positive signal trace 110 should be equal and opposite to the current in negative signal trace 112. However, radiant effect of current of negative signal trace 108 alter the current in positive signal trace 110, whereas the radiant effect of current of positive signal trace 106 will alter the negative signal trace 112. For simplicity of explanation, let the "alteration" the current in positive signal trace 110 be an attenuation, and let of the "alteration" the current in positive signal trace 110 additionally be an attenuation. The attenuation of the signal in negative signal trace 112 is less than the attenuation of the signal in positive signal trace 110 because r2<r3. The difference in interference creates a distortion in the signal if positive signal trace 110 and negative signal trace 112 are attenuated differently. Even though the interference may be minor, the interference calculation is integrated over the length of distance 114 or L as described by Equation 1.
In order to reduce crosstalk, conventional systems cross or switch conductors of a differential pair in order to balance the coupling between the differential pairs which will be further discussed with reference to FIG. 2.
FIG. 2 illustrates an example conventional transmission line system 200, wherein one set of signal traces include a crossover.
As shown in the figure, prior to a crossover point 206, positive signal trace 110 is separated from negative signal trace 108 by distance 116 (indicated by r1), whereas negative signal trace 112 is separated from positive signal trace 106 by distance 120 (indicated by r3). After crossover point 206, negative signal trace 112 is separated from negative signal trace 108 by distance 116 (indicated by r1), whereas positive signal trace 110 is separated from positive signal trace 106 by distance 120 (indicated by r3). For purposes of discussion, let crossover point 206 be in the middle of distance L.
The radiant effects of the current of negative signal trace 108 as felt by positive signal trace 110 from the left of the figure to crossover point 206 is equal in magnitude and opposite in sign to the radiant effects of the current of negative signal trace 108 as felt by negative signal trace 112 crossover point 206 to the right of the figure. Accordingly, the radiant effects of the current from the left side of the figure to the right side of the figure cancel each other out. Similarly, the radiant effects of the current of positive signal trace 106 as felt by negative signal trace 112 from the left of the figure to crossover point 206 is equal in magnitude and opposite in sign to the radiant effects of current of positive signal trace 106 as felt by positive signal trace 110 crossover point 206 to the right of the figure. Accordingly, the radiant effects of the current from the left side of the figure to the right side of the figure cancel each other out. Canceling the radiant effects is the purpose or goal of performing the crossover in differential pairs. Conventionally, crossovers are formed by "tunneling" below one of the signal traces.
Similar to performing crossovers with differential pairs, crossovers may be performed with bond wires as discussed with respect to FIGS. 3A-5D.
Crosstalk interference may additionally originate from other portions of a semiconductor device, namely bond wires.
A common semiconductor component encapsulates a semiconductor device in a package and uses bond wires to form a connection between the bond pads associated with the semiconductor device and the bond pads associated with the package. Bond wires may be adhered or welded to bond pads using some combination of heat, pressure and ultrasonic energy.
In a wirebond design the bond wire pair to bond wire pair coupling ranges from −17 dB to −38 dB for a range of spacing from 1(K) microns to 550 microns between the pairs. For a multi-channel Serdes link, the pairs need to be spaced at 600 microns or closer to get a reasonable number of channels into a given design. This is generally the case for wirebond designs, as wirebond designs are typically limited to 25 high speed input/output signal connections.
The standard solution for reducing bond wire to bond wire coupling is to space the pairs further and further apart. However, today's modem semiconductor die designs with large numbers of high speed input/output signals do not provide enough space to support −60 dB coupling.
Aspects of the conventional technology for bond wires associated with semiconductor packaging will now be described in greater detail with reference to FIGS. 3A-5D.
FIG. 3A illustrates a conventional bond wire configuration associated with a semiconductor device and a package.
A bond wire configuration 300 includes a semiconductor device 302, a package 304, a differential pair 305 and a differential pair 306. Differential pair 305 includes a bond wire 307 and a bond wire 308. Differential pair 306 includes a bond wire 310 and a bond wire 312. Semiconductor device 302 includes a bond pad 314, a bond pad 316, a bond pad 318 and a bond pad 320. Package 304 includes a bond pad 322, a bond pad 324, a bond pad 326 and a bond pad 328.
A signal (or power) line (not shown) on bond pad 314 connects to a corresponding signal (or power) line (not shown) on bond pad 322 via bond wire 307. A signal (or power) line (not shown) on bond pad 316 connects to a signal (or power) line (not shown) on bond pad 324 via bond wire 308. A signal (or power) line (not shown) on bond pad 318 connects to a signal (or power) line (not shown) on bond pad 326 via bond wire 310. A signal (or power) line (not shown) on bond pad 320 connects to a signal (or power) line (not shown) on bond pad 328 via bond wire 312.
Semiconductor device 302 provides electrical circuitry for electrical operations. Non-limiting examples for semiconductor device 302 include microprocessor and memory. Package 304 provides carriage and protection for semiconductor device 302. Differential pair 305 provides a transmission medium for transferring an electrical signal. Differential pair 306 provides a transmission medium for transferring an electrical signal. Bond pad 314. 316, 318 and 320 provide electrical connection to circuitry associated with semiconductor device 302. Bond pad 322, 324, 326 and bond pad 328 provide electrical connection to leads associated with package 304. As a non-limiting example, leads may be surface mount capable.
In operation, electrical signals traverse from semiconductor device 302 to bond pads 314, 316, 318, and 320. Furthermore, electrical signals traverse from bond pads 314, 316, 318 and 320 to bond pad 322, 324, 326, and 328 via bond wire 307, 308, 310 and 312, respectively. Furthermore, electrical signals traverse from bond pad 322, 324, 326 and 328 to electrical leads. Furthermore, electrical signals traverse from electrical leads to other electrical and electronic devices located external to package 304. Furthermore, crosstalk may occur between the bond wires and cause signaling errors. Crosstalk is a phenomenon by which a signal transmitted on one circuit or channel creates an unwanted effect in another circuit or channel. Crosstalk is typically caused by unwanted capacitive, inductive or conductive coupling from one circuit, part of a circuit or channel, to another. In general, the closer in distance channels are collocated, the greater the chance of experiencing crosstalk and conversely, the further the channels are collocated, the smaller the chance of experiencing crosstalk.
As an example, the separation between bond wire 307 and bond wire 308 and between bond wire 310 and bond wire 312 at semiconductor device 302 is configured for 70 microns. Furthermore, the separation between bond wire 307 and bond wire 308 and between bond wire 310 and bond wire 312 at package 304 is 100) microns. Furthermore, the distance between bond wire 307 and bond wire 312 at semiconductor device 302 is configured for 400 microns. Furthermore, the distance between bond wire 307 and bond wire 312 at package 304 is 400 microns. Furthermore, the distance between bond wire 308 and bond wire 310 at semiconductor device 302 is 70 microns.
In order to reduce issues associated with crosstalk, the separation between bond wires may be increased as will be discussed with reference to FIG. 3B.
FIG. 3B illustrates a conventional bond wire configuration associated with a semiconductor device and a package where bond wire separation is increased over the separation depicted in FIG. 3A.
As shown in FIG. 3B (and similar to the situation of FIG. 3A), the separation between bond wire 307 and bond wire 308 at semiconductor device 302 remains 70 microns and the separation between bond wire 307 and 308 at package 304 remains 100 microns.
However, as shown in FIG. 3B, the separation between bond wire 307 and bond wire 312 at semiconductor device 302 is 310 microns. This is a 90 micron decrease (22.5%) in distance of the similar separation of FIG. 3A. As shown in FIG. 3B (similar to the situation of FIG. 3A), the separation between bond wire 307 and bond wire 312 at package 304 is 400 microns. The separation between bond wire 308 and bond wire 310 at semiconductor device 302 is 170 microns. This is a 100 micron increase (142%) in distance of the similar separation of FIG. 3A. As shown in FIG. 3B, the separation between bond wire 308 and bond wire 310 at package 304 is 200 microns. This is a 100 micron (100%) increase in distance of the similar separation of FIG. 3A.
The increased separation of bond wires, as shown in FIG. 3B, provided less signal interference. As an example, the noise margin for the configuration as illustrated in FIG. 3B may experience a 10 dB improvement over FIG. 3A, as crosstalk is reduced due to the increased distance between bond wire 308 and bond wire 310.
FIG. 3C illustrates a conventional bond wire configuration associated with a semiconductor device and a package where bond wire separation is further increased over the separation depicted in FIG. 3B.
As shown in FIG. 3C (and similar to the situation of FIGS. 3A-B), the separation between bond wire 307 and bond wire 308 at semiconductor device 302 remains 70 microns and the separation between bond wire 307 and 308 at package 304 remains 100 microns.
As further shown in FIG. 3C, the separation between bond wire 307 and bond wire 312 at semiconductor device 302 is 410 microns. This is a 10 micron increase (2.5%) in distance of the similar separation of FIG. 3A and a 100 micron increase (32%) in distance of the similar separation of FIG. 3B. As shown in FIG. 3C, the separation between bond wire 307 and bond wire 312 at package 304 is 300 microns. This is a 100) micron increase (25%) in distance of the similar separation of FIGS. 3A-B. As shown in FIG. 3C, the separation between bond wire 308 and bond wire 310 at semiconductor device 302 is 270 microns. This is a 200 micron increase (285%) in distance of the similar separation of FIG. 3A and a 100 micron (58%) increase in distance of the similar separation of FIG. 3B. As shown in FIG. 3C, the separation between bond wire 308 and bond wire 310 at package 304 is 400 microns. This is a 300 micron increase (300%) in distance of the similar separation of FIG. 3A and a 200 micron increase (200%) in distance of the similar separation of FIG. 3B.
The noise margin for the configuration as illustrated in FIG. 3C may experience a 6 dB improvement over FIG. 38, as crosstalk is reduced due to the increased distance between bond wire 308 and bond wire 310.
In order to reduce issues associated with crosstalk, the separation between bond wires may be increased as will be discussed with reference to FIG. 3D.
FIG. 3D illustrates a conventional bond wire configuration associated with a semiconductor device and a package where bond wire separation is increased over the separation depicted in FIG. 3C.
As shown in FIG. 3D (and similar to the situation of FIGS. 3A-B), the separation between bond wire 307 and bond wire 308 at semiconductor device 302 remains 70 microns and the separation between bond wire 307 and 308 at package 304 remains 100 microns.
As further shown in FIG. 3D, the separation between bond wire 307 and bond wire 312 at semiconductor device 302 is 510 microns. This is a 110 micron increase (27.5%) in distance of the similar separation of FIG. 3A, a 200 micron increase (64.5%) in distance of the similar separation of FIG. 3B and a 100 micron increase (24.3%) in distance of the similar separation of FIG. 3C. As shown in FIG. 3D, the separation between bond wire 307 and bond wire 312 at package 304 is 600 microns. This is a 200 micron increase (50%) in distance of the similar separation of FIGS. 3A-B and a 100 micron increase (25%) in distance of the similar separation of FIG. 3C. The separation between bond wire 308 and bond wire 310 at semiconductor device 302 is 370 microns. This is a 300 micron increase (429%) in distance of the similar separation of FIG. 3A, a 200 micron (118%) increase in distance of the similar separation of FIG. 3B and a 100 micron (37%) increase in distance of the similar separation of FIG. 3C. As shown in FIG. 3D, the separation between bond wire 308 and bond wire 310 at package 304 is 400 microns. This is a 300 micron increase (300%) in distance of the similar separation of FIG. 3A, a 200 micron increase (200%) in distance of the similar separation of FIG. 3B and the same distance of the similar separation of FIG. 3C.
As an example, the noise margin for the configuration as illustrated in FIG. 3C may experience a 5 dB improvement over FIG. 3C, as crosstalk is reduced due to the increased distance between bond wire 308 and bond wire 310.
Clearly, as described above with reference to FIGS. 3A-D, crosstalk may be minimized by increasing the spacing between bond wires. To minimize real estate on semiconductor device 302 package 304 bond wires should ideally be disposed as close to one another as possible. As such, an appropriate spacing between the bond wires must be determined.
Other bond wire configurations may be used in an attempt to reduce coupling. These include overlapping bond wires, as will be described with reference to FIGS. 4A-C
FIG. 4A illustrates a conventional overlapped bond wire configuration associated with a semiconductor device and a package.
A bond wire configuration 400 includes a semiconductor device 402, a package 404, a bond wire 407, a bond wire 408, a bond wire 410 and a bond wire 412. Semiconductor device 402 includes a bond pad 414, a bond pad 416, a bond pad 418 and a bond pad 420. Package 404 includes a bond pad 422, a bond pad 424, a bond pad 426 and a bond pad 428.
A signal (or power) line (not shown) on bond pad 414 connects to a signal (or power) line (not shown) on bond pad 422 via bond wire 407. A signal (or power) line (not shown) on bond pad 416 connects to a signal (or power) line (not shown) on bond pad 424 via bond wire 408. A signal (or power) line (not shown) on bond pad 418 connects to a signal (or power) line (not shown) on bond pad 426 via bond wire 410. Bond pad 420 connects to bond pad 428 via bond wire 412.
The separation between bond wire 407 and bond wire 408 and between bond wire 410 and bond wire 412 at semiconductor device 402 is configured for 0 microns. Similarly, the separation between bond wire 407 and bond wire 408 and between bond wire 410 and bond wire 412 at package 404 is 0 microns. The distance between bond wire 407 and bond wire 412 at semiconductor device 402 is configured for 140 microns. The distance between bond wire 407 and bond wire 412 at package 404 is 200 microns. Similarly, the distance between bond wire 408 and bond wire 410 at semiconductor device 402 is 140 microns and the distance between bond wire 408 and bond wire 410 at package 404 is 200 microns.
Semiconductor device 402 provides electrical circuitry for electrical operations. Non-limiting examples for semiconductor device 402 include microprocessor and memory. Package 404 provides carriage and protection for semiconductor device 402. Bond pad 414, 416, 418 and 420 provide electrical connection to circuitry associated with semiconductor device 402. Bond pad 422, 424, 426 and bond pad 428 provide electrical connection to leads associated with package 404. As a non-limiting example, leads may be surface mount capable.
In operation, electrical signals traverse from semiconductor device 402 to bond pads 414, 416, 418 and 420. Furthermore, electrical signals traverse from bond pads 414, 416, 418 and 420 to bond pad 422, 424, 426 and 428 via bond wire 407, 408, 410 and 412, respectively. Furthermore, electrical signals traverse from bond pad 422, 424, 426 and 428 to electrical leads. Furthermore, electrical signals traverse from electrical leads to other electrical and electronic devices located external to package 404. Furthermore, crosstalk may occur between the bond wires and cause signaling errors.
The inductive coupling between the pair of bond wires 407 and 408 and the pair of bond wires 410 and 412 is calculated as −16.76 dB.
Similar to differential pairs, as discussed above with reference to FIGS. 1-2, in order to reduce issues associated with crosstalk in bond wires, the separation between bond wires may be increased, as will be discussed with reference to FIG. 4B.
FIG. 4B illustrates a conventional overlapped bond wire configuration associated with a semiconductor device and a package where bond wire separation is increased over the separation depicted in FIG. 4A.
The separation between bond wire 407 and bond wire 408 at semiconductor device 402 remains 0 microns and the separation between bond wire 407 and 408 at package 404 remains 0 microns as described with reference to FIG. 4A.
The separation between bond wire 407 and bond wire 412 at semiconductor device 402 is 340 microns. This is a 200 micron increase (143%) in distance of the similar separation of FIG. 4A. As shown in FIG. 48, the separation between bond wire 407 and bond wire 412 at package 404 is 400 microns. This is a 200 micron increase (100%) in distance of the similar separation of FIG. 4A.
The inductive coupling between the pair of bond wires 407 and 408 and the pair of bond wires 410 and 412 is calculated as −27.21 dB, which is an improvement of −10.45 dB over the configuration of FIG. 4A. The increased separation between the bond wires increases the noise margin, decreases the coupling and decreases crosstalk.
In order to further reduce issues associated with crosstalk, the separation between bond wires may be further increased as will be discussed with reference to FIG. 4C.
FIG. 4C illustrates a conventional overlapped bond wire configuration associated with a semiconductor device and a package where bond wire separation is increased over the separation depicted in FIG. 4B.
The separation between bond wire 407 and bond wire 408 at semiconductor device 402 remains 0 microns and the separation between bond wire 407 and 408 at package 404 remains 0 microns as described with reference to FIG. 4A.
The separation between bond wire 407 and bond wire 412 at semiconductor device 402 is 540 microns. This is a 400) micron increase (285%) in distance of the similar separation of FIG. 4A and a 200 micron increase (58.8%) in distance of the similar separation of FIG. 4B. As shown in FIG. 4C, the separation between bond wire 407 and bond wire 412 at package 404 is 600 microns. This is a 400 micron increase (200%) in distance of the similar separation of FIG. 4A and a 200 micron increase (50%) in distance of the similar separation of FIG. 4B.
The inductive coupling between the pair of bond wires 407 and 408 and the pair of bond wires 410 and 412 pair is calculated as −32.13 dB, which is an improvement of −4.92 dB over the configuration of FIG. 4B. The increased separation between the bond wires increases the noise margin, decreases the coupling and decreases crosstalk.
FIG. 4C illustrates a conventional overlapped bond wire configuration associated with a semiconductor device and a package where bond wire separation is increased over the separation depicted in FIG. 4B resulting in increased noise margin and decreased crosstalk.
Clearly, as described above with reference to FIGS. 6A-C, crosstalk may be minimized by increasing the spacing between bond wires. To minimize real estate on semiconductor device 402 package 404 bond wires should ideally be disposed as close to one another as possible. As such, an appropriate spacing between the bond wires must be determined.
Similar to methods of reducing crosstalk for differential pairs as discussed above with reference to FIGS. 1-2, crosstalk originating from bond wires may be reduced with orthogonal crossovers. This will be discussed with reference to FIGS. 5A-D
FIG. 5A illustrates a conventional crossed bond wire configuration associated with a semiconductor device and a package.
A bond wire configuration 500 includes a semiconductor device 502, a package 504, a differential pair 505 and a differential pair 506. Differential pair SOS includes a bond wire 507 and a bond wire 508. Differential pair 506 includes a bond wire 510 and a bond wire 512. Semiconductor device 502 includes a plurality of bond pads to which one end of the respective bond wires are adhered to. Package 504 includes a plurality of bond pads to which one end of the respective bond wires are adhered to.
For this configuration, bond wire 507 crosses over and above bond wire 508, whereas bond wire 512 crosses over and above bond wire 510.
The separation between bond wire 507 and bond wire 512 at semiconductor device 502 is 210 microns. The separation between bond wire 508 and bond wire 510 at package 504 is 400 microns.
The inductive coupling between the pair of bond wires 507 and 508 and the pair of bond wires 510 and 512 is calculated as −18.79 dB.
The coupling between the bond wires is dependent upon the point of crossing between the bond wires and upon the orientation between the bond wires. A variety of crossing bond wire configurations will be described with reference to FIGS. 5B-D below which have a variety of coupling values.
FIG. 5B illustrates a conventional crossed bond wire configuration associated with a semiconductor device and a package where bond wire orientation is varied as compared to FIG. 5A.
As shown in FIG. 5B, the separation between the bond wires at semiconductor device 502 and at package 504 is the same as described with reference to FIG. 5A, however the height of the bond wires is varied slightly.
In FIG. 5B, the inductive coupling between the pair of bond wires 507 and 508 and the pair of bond wires 510 and 512 pair is calculated as −17.53 dB. Furthermore, the −17.53 dB coupling is 1.26 dB greater than the configuration described with reference to FIG. 5A even though the difference between FIG. 5A and FIG. 5B is related to the height of the bond wires and not the separation between the bond wires at the bond pads.
FIG. 5C illustrates another example conventional crossed bond wire configuration associated with a semiconductor device and a package.
As shown in FIG. 5C, the separation between the pair of bond wires 507 and 508 and the pair of bond wires 510 and 512 is increased as compared to FIGS. 5A-B. The separation between the pair of bond wires 507 and 512 at semiconductor device 502 has been increased to 240 microns. This is a 30 micron increase (14%) in distance of the similar separation of FIGS. 5A-B. As shown in FIG. 5C, the separation between bond wire 508 and bond wire 510 at package 504 remains 400 microns.
The inductive coupling between the pair of bond wires 507 and 508 and the pair of bond wires 510 and 512 is calculated as −24.54 dB. The −24.54 dB coupling is 5.75 dB less than FIG. 5A and is 7.01 dB less than FIG. 5B.
FIG. 5D illustrates another example conventional crossed bond wire configuration associated with a semiconductor device and a package.
The separation between bond wire 507 and bond wire 512 at semiconductor device 502 is 240 microns, the same as described with reference to FIG. 3C. The separation between bond wire 508 and bond wire 510 at package 504 is 400 microns. The 400 microns is an increase of 100 microns over the separation as described with reference to FIG. 3C.
In FIG. 3C, the larger separation is 500 microns, whereas here the larger separation is 400 microns—meaning a tighter overall bondwire pitch while the isolation has improved from −23 dB to −27 dB.
The inductive coupling between the pair of bond wires 507 and 508 and the pair of bond wires 510 and 512 is calculated as −26.47 dB. The −26.48 dB coupling is 1.93 dB less than FIG. 5C.
What is needed is a system and method for decreasing crosstalk associated with differential pairs and bond wires.

System and method of crossover determination in differential pair and bondwire pairs to minimize crosstalk


The invention concerns a composition comprising a first polyamide, a second polyamide, different from the first polyamide, and 0.1 to 5% by weight of carbonaceous nanofillers, in which: a) the first polyamide comprises a unit derived from the condensation of meta-xylylene diamine or from a mixture of meta-xylylene diamine and para-xylylene diamine with sebacic acid, said first polyamide having a melting temperature Tf1; and b) the second polyamide has a melting temperature Tf2 higher than or equal to Tf1−40° C. The invention also relates to a method for producing said composition and the use thereof for producing various items.

Among the polyamides known to date, some exhibit a major advantage as a result of their noteworthy mechanical properties, in particular due to their high tensile and flexural moduli.
Mention may in particular be made of polyphthalamides (PPAs), which are semiaromatic polyamides which exhibit a high tensile modulus of the order of 3 GPa. This is also the case with polyamide MXD.6, the product of the condensation of MXD and adipic acid, MXD denoting meta-xylylenediamine (optionally mixed with a minor amount of para-xylylenediamine or PXD).
While PPAs and MXD.6 are highly satisfactory in terms of mechanical properties (in particular high tensile modulus), they however exhibit two major disadvantages:                First, in view of their high melting point, PPAs and MXD.6 exhibit a high transformation temperature (typically of greater than 280° C.). In addition to being energy-intensive, the use at a high transformation temperature limits the introduction, into the compositions based on PPAs or MXD.6, of certain reinforcers and/or additives which decompose at such temperatures.        Secondly, as a result of their glass transition temperature (Tg), which is also high, and their slow kinetics of crystallization, the shaping of the materials based on PPAs or on MXD.6 requires operating at relatively high mold temperatures, typically of the order of 120° C. to 130° C. (30 to 40° C. above the Tg), in order to obtain maximum crystallization and thus to confer, on the material, optimum mechanical and dimensional stability properties.
More particularly, during the shaping by injection molding of the materials based on PPAs or MXD.6, it is necessary to use molds using oil as heat-exchange fluid, such molds being more restricting in use and less widespread at molders than molds using water as heat-exchange fluid.
In order to optimize the crystallization of a composition based on MXD.6, the paper entitled Effect of Nucleating Additives on Crystallization of Poly(m-xylylene adipamide) and published in the review Polymer Engineering and Science in 2007, pp. 365-373, provides for the introduction of nucleating agents, in the case in point talc and PA 6.6, the melting point of which is of the order of 250° C.
The polyamide MXD.10, the product of the condensation of MXD and sebacic acid (decanedioic acid), also exhibits good mechanical properties and in particular a high tensile modulus.
As MXD.10 exhibits a lower melting point (of approximately 193° C.) than that of PPAs or MXD.6, its transformation temperature of between 200° C. and 270° C., and more generally of between 210° C. and 260° C., is lower than that of PPAs and MXD.6, which limits the energy consumption. Furthermore, it is possible to envisage compositions based on MXD.10 comprising certain reinforcers and/or additives which decompose at the transformation temperatures of PPAs and MXD.6.
Furthermore, the density of MXD.10 is lower than that generally observed with regard to PPAs or MXD.6. Thus, the objects obtained from compositions based on MXD.10 exhibit the advantage of being lighter, compared with those obtained from compositions based on PPA or on MXD.6.
On the other hand, as in the case of PPAs or MXD.6, a high mold temperature (typically of the order of 120° C.) is necessary during its shaping by injection molding in order to ensure maximum crystallization of the product and thus to confer optimum mechanical and dimensional stability properties.
In order to improve the molding conditions of a composition based on MXD.10, in particular by lowering the duration of the cooling stage during the shaping by injection molding, the document EP 0 272 503 provides for the addition, to a composition comprising 100 parts by weight of polyamide MXD.10, of from 1 to 20 parts by weight of a crystalline polyamide having a melting point greater by approximately 20 to 30° C. than that of MXD.10.
The crystalline polyamide thus behaves as a nucleating agent, in the absence of any other nucleating agent of the inorganic filler type, such as the talc mentioned above.
In the document EP 0 272 503, the best molding conditions, in particular a rapid cycle, are obtained for a mold temperature of 130° C.
Furthermore, the document WO 2011/010039 describes a composition based on polyamide of MXD.10 type having a melting point Tf1, comprising a second polyamide having a melting point Tf2 of between Tf1−40° C. and Tf1+20° C. This second polyamide acts as nucleating agent. It makes it possible to control the crystallization of the composition.
However, there still exists a need to succeed in accelerating the kinetics of crystallization of a composition based on polyamide, and in particular based on MXD.10 or the like, while retaining the mechanical and dimensional stability properties of the crystalline material.


Devices, methods, and software are disclosed for determining dimensions of a physical object using a mobile computer equipped with a motion sensing device. In an illustrative embodiment, the mobile computer can comprise a microprocessor, a memory, a user interface, a motion sensing device, and a dimensioning program executable by the microprocessor. The processor can be in communicative connection with executable instructions for enabling the processor for various steps. One step includes initiating a trajectory tracking mode responsive to receiving a first user interface action. Another step includes tracking the mobile computer's trajectory along a surface of a physical object by storing in the memory a plurality of motion sensing data items outputted by the motion sensing device. Another step includes exiting the trajectory tracking mode responsive to receiving a second user interface action. Another step includes calculating three dimensions of a minimum bounding box corresponding to the physical object.

In several logistics use cases, dimensions of a package or a parcel need to be determined, for example, in order to ascertain that maximum size limits imposed by a carrier have not been exceeded, or to calculate shipping costs based on estimated volumetric weight.
The discussion above is merely provided for general background information and is not intended to be used as an aid in determining the scope of the claimed subject matter.

Measuring object dimensions using mobile computer


A screw cap twisting tool uses two primary members—a stationary member with gripping surface(s) and a high-mechanical-advantage-for-gripping pivoting member with gripping surface(s)—to easily and effectively grip and twist a screw cap. The screw cap twisting tool is easily operated by pushing the screw cap against the pivoting member. A screw cap twisting tool also uses a method for holding the pivoting member in its most open position before screw cap insertion. This method for holding the pivoting member in its most open position can be accomplished in numerous ways by using a force opposing feature, member, or mechanism that allows movement and/or deformation when force is applied and restores position and/or shape when force is removed. Examples include, but are not limited to: built-in elastic metal or plastic material, separate metal or plastic spring, separate elastic O-ring or rubber band, gravity, or magnetism.

Because twist type bottle caps can be difficult to twist—especially for people who have reduced hand function caused by age, arthritis, accident, congenital disability, or the like—numerous devices have been developed to make the process easier. Although there have been numerous screw cap twisting tool patents filed and awarded, very few of these devices can be found in the marketplace. There are two main reasons for this: first, some devices do not provide enough mechanical advantage to make twisting significantly easier and second, some devices are cumbersome to operate—being difficult to manipulate, not easily gripping well, and/or wearing out too quickly. The goal of the present screw cap twisting tool invention is to provide both ease of use and high mechanical advantage for gripping. The two basic approaches to cap twisting tool operation appear to be either squeeze and twist or push and twist wherein the cap interfacing mechanism is primarily flexible or rigid. (Cap twisting tools that have elastic gripping materials on the surfaces of rigid parts would still be classified as primarily rigid.) When classified in this way, the prior art appears to fall into five main categories: flexible push, flexible squeeze, rigid-hinged squeeze, rigid-sliding squeeze, and conical push. The present invention falls into a unique rigid hinged push category wherein the tool is easy to operate—push and twist—and provides high mechanical advantage for gripping—rigid hinged with significant leverage. The prior art appears to emphasize only one of the two goals. Either it is easy to use but provides insufficient mechanical advantage for gripping, or it provides high mechanical advantage for gripping but is more difficult to operate. The present invention provides both ease of use and high mechanical advantage for gripping.


In one embodiment, a melt-castable energetic material comprises at least one of: 3,5-bis(4-nitro-1,2,5-oxadiazol-3-yl)-1,2,4-oxadiazole (DNFO), and 3-(4-amino-1,2,5-oxadiazol-3-yl)-5-(4-nitro-1,2,5-oxadiazol-3-yl)-1,2,4-oxadiazole (ANFO). In another embodiment, a method for forming a melt-castable energetic material includes reacting 3,5-bis(4-amino-1,2,5-oxadiazol-3-yl)-1,2,4-oxadiazole (DAFO) with oxygen or an oxygen-containing compound to form a mixture of at least: DNFO, and ANFO.

Insensitive highly energetic compounds are very useful materials which may be used in a number of different applications, including explosives, propellants, weapons, etc. Trinitrotoluene (TNT) and 1,3,5-triamino-2,4,6-trinitrobenzene (TATB) are examples of common insensitive highly energetic compounds, which may take any desired form, and may be activated/detonated using an initiator, such as a blasting cap, an electrical signal, etc.
Castable energetic compounds are generally classified as either melt-castable or cast-cured. Melt-castable systems include those in which the energetic compound may be melted and cast into a munition. Cast-cured systems involve a mixture of one or more energetic compounds with a polymeric binder, cross-linker, plasticizer, and catalyst that is cast into a munition and allowed to cure in place. Both of these approaches are useful when using insensitive highly energetic compounds to prepare them for use as weapons/explosives/propellants.
Insensitive energetic compounds tend to be relatively stable, meaning that the energetic compounds will not explode easily in response to shock, fire, physical contact, etc. Instead, they preferably activate/detonate in response to an intended initiation.

Melt-castable energetic compounds comprising oxadiazoles and methods of production thereof

Lawrence Livermore National Security, LLC


A float valve with upper and lower valve bodies having axial flow there through and valve member having angular trailing edges at a swept back angle for providing a seating surface and a stem axially extending from the valve member. The stem having multiple supporting surfaces arranged cylindrically and having a biasing member fitted there about. The upper valve body having an internal annular seat for seating with the valve member seating surface and external seals for engaging oilfield tubulars and threaded on one end. The lower valve body having a central internal support member for support of the valve member stem for axial movement and threaded on one end for joining the upper valve body and compressing the biasing member to engage the seating surfaces of the valve member and internal annular seat of the upper valve body for engagement and disengagement in response to fluid flow pressure.

1. Field of the Invention
The present invention relates to an improved float valve of the type used in hydrocarbon recovery operations with oilfield tubular materials in downhole operations. More particularly this invention relates to a float valve which can be used in either vertical or horizontal well bores and provides smooth functionality in the transition between vertical or horizontal well bores and improved life of the float valve. The invention further relates to the ease of the float valve assembly for all its parts and for precise and exact tolerance relationships for all its parts when assembled. The invention provides improved fluid flow through the float valve and sealing relationship by providing functionally improved angles between its seating surfaces. Also this invention provides improved fluid flow through the float valve by improved configurations of the axial stem of the valve member movably mounted in the float valve. This invention also provides surfaces and landing sites on the float valve for technology associated with sub joint strainers, spiders or X-collar filters to be used in cooperation with the float valve for improved performance.
2. Background of the Invention
Float valves have long been used in oilfield drilling operations with drilling fluids for drilling oil and gas wells. However over time, improvements have been made to drilling operations which include lateral wells, as well as vertical wells, and ever more exotic drilling fluids, gels and even high pressure air had been put into use. The new drilling fluids pass through the drill string like the older drilling fluids, and through the float valve but create new and enhanced stress and wear on the float valves, especially in lateral wells. In the case of high pressure air drilling operations for example, a float valve may open and close in excess of a hundred times per minute thereby exerting excessive forces on the moving valve member parts. Also new components have been developed for drilling fluid such as glass or other kinds of beads which are very fine, but abrasive, and can stick between moving parts of a float valve. Further lateral wells put the float valve and drilling head into a different gravitational alignment than vertical drilling which can cause wear and alignment problems with moving parts of a float valve.
The float valve is generally installed in a tubular string for running in a well bore by installing the float valve in a float body or bored-out drill collar of a tubular string. The float body may be positioned between two joints in a tubular string and is conventionally connected to the tubular string with conventional oilfield tubular threads such as a threaded box and pin connections for sealing engagement with conventional oil field tubular threads. When the float valve is positioned within the float body, seals provided on the exterior of the float valve body engage against the interior surfaces of the float body and provide a seal against high and low pressure fluids passing between the float body and the exterior of the float valve. Once the seal between float body and the exterior of the float valve is sealed all fluids are then flowed through the float valve and controlled by the float valve.
Fluid flow through a float valve body is controlled by the pressure of the fluid being flowed against a valve member positioned within the float valve body which overcomes the valve member's sealed and seated relationship against the seat on the interior surface of the float valve body which is created by the biased engagement of a spring against the valve member. While a float valve is necessary to control backflow from within the well and allow down flow of fluids being flowed from above, a float valve also is a restriction to flow in the profile between the valve member seat and the angular seat in the interior of the float valve body even when the float valve is fully open. This restrictive flow profile can have an affect on the functionality of the drilling operation and can create wear on those parts exposed to flow. Also the flow profile opening, between the valve member seat and the angular seat of the float body, can create turbulence in the fluid passing through which can cause vibration in the moving parts of the float valve. Further vibration and turbulence in the presence of drilling fluids, which contain drilling muds, chemicals, drill cuttings, glass or other kinds of beads, etc. can have abrasive affects on the valve member at the edges of its seating surfaces and on the stem of the valve member and on the spring for creating excessive wear which leads to a short life and ultimate failure of the float valve. Also the drilling fluids can, because of their small particle size, become jammed between the moving surfaces of the valve member stem and its supporting structure within the float valve body to create problems. Also this turbulence interferes with the smooth fluid flow of the drilling fluid to the drill bit or other piece of equipment in the drill string and therefore it is desirable to have a smooth flow and as large a volume of flow as possible through a float valve.
The prior art float valves have included a unitary valve member which was cast in one piece and included both the stem and valve member head, which engaged the valve seat located in the interior of the float valve body. Due to the exotic surfaces necessary to form a seal and the high cost of manufacturing this unitary valve element, two-piece valve elements are more commonly used in float valves and joined together at their stem and valve member head by conventional means. Various means of joining the two-piece, stem and valve member head, have been used including inertia welding and other mechanical interconnectors. Even exotic special means of connection were used such as using a shrink fit operation where the valve member head/cone includes a cylindrical shaped recess for receiving a front end of the stem during the shrink fit operation, wherein the valve member head/cone is heated relative to the stem, and the stem is impressed into the cylindrical recess for union and then both are air cooled for connection. This fitting or union is subject to being damaged in drilling operations because of the elevated downhole temperatures and due to vibrations to which the valve stem and valve member head/cone are subjected, specially in lateral well forces.
The float valve bodies, into which the valve members are inserted, are today cast as a single piece unit which creates problems with assembly. Assembling such cast valves bodies requires a window in the casting to allow for the insertion and manipulation of the valve member head with its valve stem and spring into the float valve body through the window. To achieve this large clearances must be allowed for such awkward installation which often results in wobble or deviation of the valve member head and its stem within the float valve body, thereby resulting in excessive wear on the valve member head and its stem and the valve stem bearing/bushing which shorten the life of the float valve. The wobbles and deviations of the valve member head and it's stem within a float valve bodies cast as a single piece are even greater and more likely to cause failure in an horizontal wells because of gravitational forces being perpendicular to the stem and valve member head.
The prior art float valves have also tended to use elastomeric seals and valve bushings with valve member heads to affect sealing engagement and allow smooth movement of the stem within the float valve between its open and closed positions. The prior art float valves using elastomeric seals tended to use large angles for the valve member head seats which were 45° to 90° and greater, because the valve head seats were not the primary source of sealing engagement but were used in conjunction with the elastomeric seal to form the seal between valve member head and the seat of the float valve body. This arrangement formed a good seal, but as the elastomeric seals wore down from operation in the abrasive environment of drilling fluids, these prior art float valves had a shorter life and were subject to catastrophic failure. The other soft spot for failure in the prior art float valves was at the valve bushing into which the stem of the valve member head was mounted to provide a smooth surface on which to slide back and forth in the operation of opening and closing the float valve. In the current drilling fluid environment these valve bushings/bearing were rapidly destroyed by the drilling fluids and thus left the stem of the valve member head loose in its mounting which allowed wobble in the valve member head and caused early failure of the float valve. This problem is especially acute in lateral wells because of the gravitational force being perpendicular to the stem of the valve head member versus being in alignment with the gravitational forces in vertical wells.
The prior art tended to focus on creating a reliable float valve, but did not focus as much on the flow profile of the opening between the valve head member and its seat on the inside of the float valve body and the flow passage through the rest of the float valve body where the stem of the valve head member and supporting structure were located to create smooth non-turbulent flow through the float valve. Thus the prior art provided seating surfaces on the valve head member which were 45° to 90° or greater angles through the line of the flow and thus seating surface on the interior of the valve body tended to be a problem. These angles for the seating surfaces tended to push the drilling fluid out of its normal path of flow and create excess turbulence at that point of flow in the valve body. In addition, the prior art did not provide for any cover or protection of the spring member and stem to the corrosive and abrasive fluid turbulence created by the seating surfaces on the valve head member just behind the valve member head where the spring and stem were located thereby exposing them to excessive wear which caused early failure in float valves. Also the prior art stems were generally cylindrical rods mounted in a sleeve bearing/bushing which was mounted in a supporting structure within the flow way of the lower half of the valve body to support the stem for smooth and even movement in and out as the float valve was operated. The cylindrical rods and support structure for them with sleeve bearings/bushing took up a great deal of cross-sectional area in the float valve body and restricted flow and positioned the sleeve bearing/bushing directly in line with corrosive and abrasive turbulent flow of the drilling fluid causing early failure in the float valve. These failures occurred in many ways, but in at least one way, as the drilling fluids destroyed the sleeve bearing/bushing it began to open up crevices which allowed the drilling fluids and their small particles to be jammed in between the stem and sleeve bearing/bushing not only causing additional wear but in some instances prevented the stem from sliding in and out in the sleeve bearing/bushing causing failure of the float valve.
Those skilled in the art would recognize that failure of a float valve can have significant adverse consequences, because any failed piece of equipment in a drill string requires a trip out and back in to the well which interferes with drilling operations. The prior art float valves were treated as separate units apart from sub joint strainers or X-collar filters which were used apart from the float valves to stop foreign particles in the drilling fluid from being jammed into the float valves or other operational equipment below and could not and did not function in direct relationship with a float valve or could be landed and be seated on a float valve because the float valve were not built to receive such filters and strainers.

Self centering downhole float valve for vertical and lateral wells


To generate a pseudo-random sequence of multi-carrier data symbols, a pseudo-random bit sequence is produced by repetitively generating a pseudo-random sequence of L bits, L being a first integer value. To create a multi-carrier data symbol, N bits are used, N being a second integer value. The pseudo-random bit sequence is subdivided into strings of N′ bits, N′ being a third integer value larger than N, and N bits out of each string of N′ bits are used to generate a respective multi-carrier data symbol. N′-N bits out of each string of N′ bits are left unused.

The present invention relates to a method to generate a pseudo-random sequence of multi-carrier data symbols by producing a pseudo-random bit sequence by repetitively generating a pseudo-random sequence of L bits, L being a first integer value and packetizing into multi-carrier data symbols thereby using N bits of the pseudo-random bit sequence per multi-carrier data symbol, N being a second integer number, to thereby generate the pseudo-random sequence of multi-carrier data symbols, a generator of a pseudo-random sequence of multi-carrier data symbols comprising scrambling means, adapted to repetitively generate a pseudo-random sequence of L bits, L being a first integer value, to thereby produce a pseudo-random bit sequence and packetizing means, adapted to packetize into multi-carrier data symbols using N bits of said pseudo-random bit sequence per multi-carrier data symbol, N being a second integer number, to thereby generate the pseudo-random sequence of multi-carrier data symbols, a multi-carrier transmitter including a pseudo-random sequence generator and transmitting means coupled to the pseudo-random sequence generator, and adapted to transmit a pseudo-random sequence of multi-carrier symbols generated by the pseudo-random sequence generator over a communication channel, and a multi-carrier receiver including a pseudo-random sequence generator and receiving means adapted to receive a first pseudo-random sequence of multi-carrier symbols transmitted over a communication channel, and decoding means, coupled to said receiving means and to the pseudo-random sequence generator, and adapted to decode the first pseudo-random sequence of multi-carrier symbols and a second pseudo-random sequence of multi-carrier symbols generated by the pseudo-random sequence generator.
Methods and equipment to generate a pseudo-random sequence of multi-carrier data symbols are already known in the art, e.g., from the ADSL Standard Specification 'Network and Customer Installation Interfaces—Asymmetric Digital Subscriber Line (ADSL) Metallic Interface', published by the American National Standards Institute (ANSI) in 1998 and referred to by ANSI T1E1.413 Issue 2. According to this Standard Specification, the ADSL line termination at the central office generates a pseudo-random sequence of 16,384 DMT (Discrete Multi Tone) data symbols, each comprising 512 bits. The pseudo-random sequence of DMT data symbols, named C-MEDLEY in paragraph 9.6.6 of the just cited Standard Specification, is derived from a pseudo-random sequence of 511 bits generated repetitively by a scrambler in the ADSL line termination. The pseudo-random sequence of DMT data symbols, C-MEDLEY, is sent over a twisted pair telephone line towards the ADSL network termination at the customer premises and is used therein for downstream channel analysis. In a similar way, the ADSL network termination at the customer premises produces a pseudo-random sequence of 16,384 DMT data symbols each having a length of 64 bits, named R-MEDLEY in paragraph 9.7.8 of the above cited Standard Specification, and sends this pseudo-random sequence of DMT data symbols over the twisted pair telephone line towards the ADSL line termination at the central office for upstream channel analysis. The pseudo-random sequence of DMT data symbols, R-MEDLEY, is derived from a 63-bit long pseudo-random sequence of bits that is repetitively generated by a scrambler in the ADSL network termination.
In applications such as VDSL (Very High Speed Digital Subscriber Line), wherein the number of bits per multi-carrier data symbol, that will be named N throughout the remainder of this patent application, may have different values, two problems can occur in case the known technique is applied: the randomness of the sequence of multi-carrier data symbols may decrease significantly and/or the length of the pseudo-random sequence of multi-carrier data symbols may become short in comparison with the longest achievable pseudo-random sequence that contains L multi-carrier data symbols, L being the number of bits in the repetitively generated pseudo-random sequence of bits generated by the scrambler. Indeed, the length of the pseudo-random sequence of multi-carrier data symbols becomes short in case this number of bits per multi-carrier data symbol, N, relates in a certain way to the number of bits, L, in the pseudo-random sequence of bits that is repetitively generated by the scrambler, e.g., a.N=b.L with a and b being integer values respectively smaller than L and N. The number of bits in the repetitively generated pseudo-random sequence of bits, L, is typically equal to 2S−1 if the scrambler is implemented by a finite state machine and S represents the number of states of this finite state machine. Suppose, for instance, that S equals 9 and consequently that L equals 29−1=511. If each multi-carrier data symbol has a length N of 1022 bits, then, because N=2.L, each multi-carrier data symbol in the pseudo-random sequence of multi-carrier data symbols will consist of exactly the same pseudo-random sequence of 1022 bits. In this situation, the length of the pseudo-random sequence is only 1 multi-carrier data symbols, which means that there is in fact no randomness. In case other relations are satisfied between N and L, e.g., N=L−1 or N=L+1, some randomness is lost. This is so because the bits in the pseudo-random sequence are typically used pairwise to apply random rotations to the different carriers. In the case of N=L−1 or N=L+1, the pair of bits that defines the random rotation that will be applied to a single carrier can only differ in one bit between two successive multi-carrier data symbols, thus reducing the randomness of the rotations that are applied. When applied in a VDSL system, the known method may thus generate a pseudo-random sequence of multi-carrier data symbols with decreased randomness or which is rather short whereas a long random sequence of multi-carrier data symbols is required in order to be able to analyze the channel—in ADSL channel analysis involves SNR (Signal to Noise Ratio) estimation—accurately.

Method to generate a pseudo random sequence of multi carrier data symbols, and related transmitter and receiver


An example operation may include one or more of receiving a request to open a storage system, the request comprising an identification of a user that submitted the request, transmitting a notification to one or more stakeholder devices of the storage system indicating the user requests access to the storage system, receiving responses from the one or more stakeholder devices, determining, via a smart contract executing on a blockchain node associated with the storage system, whether to open the storage system based on the received responses and consensus information included in the smart contract, and storing the determination made by the smart contract as a transaction in a blockchain.

Storage facilities such as safes and other systems such as freight containers, self-storage, garages, and the like, are often used to store valuables and other items that an owner or a lessee may need but may not have room for or feels more secure storing in a locked and secured storage area. However, one of the difficulties with storage facilities is regulating access to such a system especially when the owner or lessee is not present. For example, friends, family members, workers, and others may have legitimate reasons for accessing the storage facility. In this case, the owner or the lessee may not be comfortable divulging a key, passcode, etc. for opening the storage facility. As another example, the owner or the lessee may have a biometric requirement for opening the storage and may not want to provide access to any additional users. Accordingly, what is needed is a secure way of enabling a person to remotely control secure access to a storage facility when the person in control of the storage is not present.
Meanwhile, a blockchain may be used as a public ledger to store information such as digital assets and the like. Because any individual or entity can often provide information to a blockchain, this information should be reviewed and confirmed. This operation is known as consensus. There are two types of consensus centralized and decentralized. Centralized consensus includes one central database that is used to rule transaction validity. A decentralized consensus transfers authority and trust to a decentralized network and enables its nodes to continuously and sequentially record their transactions on a public "block", creating a unique "chain" referred to as a blockchain. Cryptography, via hash codes, is used with a blockchain to secure an authentication of a transaction source and removes the need for a central intermediary.

International Business Machines Corporation


A method of forming a transition metal containing films on a substrate by a cyclical deposition process is disclosed. The method may include: contacting the substrate with a first vapor phase reactant comprising a transition metal halide compound comprising a bidentate nitrogen containing adduct ligand; and contacting the substrate with a second vapor phase reactant. A method for supplying a transition metal halide compound comprising a bidentate nitrogen containing ligand to a reaction chamber is disclosed, along with related vapor deposition apparatus.

Semiconductor device fabrication processes in advanced technology nodes generally require state of the art deposition methods for forming transition metal containing films, such as, for example, elemental transition metals, transition metal oxides, transition metal nitrides, transition metal silicides, transition metal phosphides, transition metal selenides, or transition metal borides.
A common requisite for the deposition of transition metal containing films is that the deposition process is extremely conformal. For example, conformal deposition is often required in order to uniformly deposit a transition metal containing film over three-dimensional structures including high aspect ratio features. Another common requirement for the deposition of transition metal containing films is that the deposition process is capable of depositing ultra-thin films which are continuous over a large substrate area. In the particular case wherein the transition metal containing film is electrically conductive, the deposition process may need to be optimized to produce low electrical resistance films.
Cyclical deposition processes, such as, for example, atomic layer deposition (ALD) and cyclical chemical vapor deposition (CCVD), sequential introduce one or more precursors (reactants) into a reaction chamber wherein the precursors react on the surface of the substrate one at a time in a sequential, self-limiting, manner. Cyclical deposition processes have been demonstrated which produce metal containing films with excellent conformality with atomic level thickness control.
Cyclical deposition processes may be utilized for the deposition of transition metal containing films, such as, for example, copper containing films, nickel containing films, and particularly cobalt containing films. However, chemical precursors suitable for the cyclical deposition of transition metal containing films, and particularly cobalt containing films are uncommon and cost prohibitive. For example, existing chemical precursors utilized for the cyclical deposition of cobalt containing films may require undesirable high temperature deposition processes and/or the use of plasma enhanced deposition processes. In addition, cyclical deposition processes utilizing existing cobalt chemical precursors may be undesirable due to the sensitivity of the deposition process to the material of the underlying substrate. Accordingly cyclical deposition methods, chemical precursors suitable for use in cyclical deposition processes and related vapor deposition apparatus are desirable for the formation of transition metal containing films, and particularly cobalt, copper, and nickel containing films.

Method of forming a transition metal containing film on a substrate by a cyclical deposition process, a method for supplying a transition metal halide compound to a reaction chamber, and related vapor deposition apparatus


Fault-tolerant storage is provided using a distributed data storage system that receives input data from clients and divides that data into data blocks for storage. The data blocks are processed using a coding scheme that generates redundant level one error correction blocks (L1EC Blocks). The L1EC blocks enable the reconstruction of one or more damaged or inaccessible data blocks, so long as sufficient undamaged elements are still accessible. The L1EC blocks and the data blocks are divided into distribution sets and these sets are stored at a plurality of data storage locations. At each data storage location additional level two error correction blocks (L2EC blocks) are generated that provide local data redundancy. The L2EC blocks enable reconstruction of damaged elements at a data storage location without requiring communication with the other data storage locations.

This invention relates generally to data storage technologies, in particular, to distributed fault-tolerant storage in independent storage locations.
Modern Internet-scale applications, such as social networking websites, receive and generate vast quantities of data continuously. This data includes user information, images, videos, text posts, emails, performance logs, search indices, meta data, etc. This data must be stored securely and reliably, and it must be accessible despite data disruption events such as natural disasters, power failures, disk failures, server failures, etc. In the past, reliability and accessibility of data in Internet applications was provided by storing many copies of the same data in geographically separate data centers. By having distinct, separate copies of the same data in multiple locations, a system could ensure that at least one copy of the data was accessible at any time, despite the occurrence of data disruption events.
But data mirroring has a cost associated with it. Each copy of data requires additional storage resources, and if multiple copies of the same data are maintained, the storage overhead becomes prohibitive for large data sets. One solution to this problem is to not maintain full redundant copies of the data, but rather to compute smaller recovery codes from the data, where the recovery codes allow a lost piece of the data to be recovered using the remaining data. In the simplest case a recovery code can be generated by splitting the data into N pieces and computing an XOR across the pieces. The N pieces of data can then be distributed to N separate data storage locations. If any one of the N pieces is lost, the lost piece can be reconstructed by XORing the recovery code against the remaining pieces. In this simple case the storage scheme requires 1/ N of the data as additional storage overhead to maintain the recovery codes, but this is still an improvement over the complete data duplication required in data mirroring. The simple scheme guards against the loss of only a single one of the N pieces of data, however, other methods of generating recovery codes allow for greater redundancy, but may require additional storage overhead as a tradeoff. The data storage locations can be established in geographically separate sites so that the probability of a single data disruption event effecting all locations is minimized.
Systems that provide redundant storage as described above are sometimes called Reliable Arrays of Independent Nodes (RAIN). RAIN systems are often efficient in terms of the storage overhead that they require to provide data redundancy, but they are inefficient in terms of the network usage. When a piece of data is lost at one of the nodes of a RAIN system due to a data disruption event (e.g., hard disk failure), the information to reconstruct that lost data must be fetched from other nodes since all the recovery codes and the other data pieces will not be locally stored. The RAIN system cannot keep all the recovery codes and other data pieces locally because doing so would adversely affect the fault-tolerance characteristics of the system—the failure of a single machine or location could cause the system to lose access to all the locally stored data. Therefore, when data recovery is necessary, both the recovery codes and data pieces necessary for data reconstruction must be sent over the network to the location where the lost data is being reconstructed.
Depending on the frequency and severity of data disruption events, the network traffic initiated by data reconstruction processes may cause network congestion and other issues. For extremely large data sets, such as those generated by Internet scale applications—e.g. social networking systems, search engines, web services providers, etc.—handling the traffic between data storage locations may be very expensive.

Distributed system for fault-tolerant data storage


A vehicle interior aquarium, which comprises a water tank for containing water to keep living water animals and water plants and being supported by a shock absorbing base and covered with a heat insulating top cover. A DC pump is attached to pump air into the water tank to generate air bubbles through bubble tubes. A rectangular projection is made on the top of the water tank for the fastening therein of a rectangular projection on the bottom of the top cover so as to protect from spraying of water out of the aquarium.

The present invention is related to aquariums and more particularly to an aquarium for mounting inside a vehicle to keep living water animals and water plants.
Regular aquariums are generally installed indoors for keeping living water animals and water plants. It is an idea of the present inventor to install an aquarium inside a vehicle by utilizing the batteries of a vehicle to constantly operate an air pump to pump air into the aquarium. By means of constantly turning on the power of a vehicle, a vehicle is easy to start in all conditions, and because of the installation of an aquarium inside a vehicle, a driver may have less tendency to speed.


A method of searching an electronic commerce website includes searching a plurality of user profiles based upon a user-supplied search query for an item, establishing an interactive online session between the user and the at least one search facilitator, and providing for the at least one search facilitator to present one or more suggested item listings to a user through the electronic commerce website. The searching identifies at least one search facilitator profile among the plurality of user profiles. The search facilitator profile represents a search facilitator who can assist the user in locating the item within the electronic commerce website.

1. Field of Invention
Embodiments of the present invention relate generally to electronic commerce, and more specifically, to online searches for items within an electronic commerce environment.
2. Discussion of Related Art
Many online resources provide utilities that support searches for information, such as items for sale at an electronic commerce website (also referred to herein as an e-commerce website). To begin a search, typically a website user supplies one or more search terms that are descriptive of the information sought to a search engine within the website. The search engine then processes the search query to identify relevant results from a collection of information (e.g., stored within a database), and then returns the results to the user. The results are automatically generated using algorithms that attempt to match the search query against information in the collection. Being automated, the quality of the results returned by the search engine is largely dependent upon the specificity of the search query, the specificity of the information in the collection, and the ability of the search algorithms to locate and identify information relevant to the query. In some cases, the search results may not be accurate, current, relevant, or satisfactory to the user.

Systems and methods for searching in an electronic commerce environment


An air purification device (100), a lighting device and a luminaire are provided. The air purification device comprises an air inlet (132), an air outlet (134), a photocatalytic volume (150), a first solid state light emitter (102) and a second solid state light emitter (122). The air inlet receives an air flow (140). The photocatalytic volume comprises a photocatalytic material and the air flow flows through the photocatalytic volume to contact some air with the photocatalytic material. The photocatalytic volume is between the air inlet and the air outlet. The photocatalytic material is a catalyst under the influence of UV light in photoreactions between gasses in the air flow. The first solid state light emitter emits UV light towards the photocatalytic volume. The second solid state light emitter emits deep blue light towards the photocatalytic volume. The deep blue light has a peak wavelength in between (400) nanometer and (450) nanometer.

Published patent application WO2014/097089, which is incorporated by reference, discloses a lighting unit and a luminaire for illumination and for purifying air. The lighting unit comprises a photocatalytic volume through which, in use, air flows. The photocatalytic volume comprises photocatalytic material that is configured to be a catalyst in photoreactions between gasses in the air flow under the influence of light that impinges on the material. The lighting unit at least comprises a solid state light emitter that emits light towards the photocatalytic volume and the emitted light at least comprises light that assists the photoreactions between the gasses in the air flow.
The photocatalytic volume of the lighting unit of the cited document comprises open spaces, such as pores or holes, through which the air flow is able to flow from one side of the photocatalytic volume to another side of the photocatalytic volume. In many typical use cases it might be that inside these open spaces, or at the entry windows of the open spaces, bacteria colonies start to grow because such bacteria are delivered from the ambient onto the surfaces of the photocatalytic volume by the air flow and because there is quite often a relatively good climate for such bacteria to grow in the lighting unit. In relatively humid and/or warm climates, water may condensate in the lighting unit and then the water and the relatively high temperature provide a very good climate for the bacteria to grow. If too many colonies of bacteria are formed, no effective air purification is possible anymore because the photocatalytic volume may become less permeable for air and the bacteria or debris of the bacteria may provide unpleasant compounds (in the gaseous phase) to the air that flows through the photocatalytic volume. Furthermore, the large number of bacteria colonies may induce health risks because the gasses released by the bacteria or the debris may be poisonous and/or more bacteria may be present in the air flow that leaves the lighting unit of the cited patent application than there are present in the flow that enters the lighting unit.

Air purification device, a lighting device and a luminaire


A data processing system 2 includes a single instruction multiple data register file 12 and single instruction multiple processing circuitry 14. The single instruction multiple data processing circuitry 14 supports execution of cryptographic processing instructions for performing parts of a hash algorithm. The operands are stored within the single instruction multiple data register file 12. The cryptographic support instructions do not follow normal lane-based processing and generate output operands in which the different portions of the output operand depend upon multiple different elements within the input operand.

1. Field of the Invention
This invention relates to the field of data processing systems. More particularly, this invention relates to the provision of cryptographic support instructions within data processing systems.
2. Description of the Prior Art
It is known to use data processing systems to perform cryptographic operations. Examples of such known cryptographic processing operations include the Secure Hash Algorithm (SHA). The SHA has a variety of different known forms including SHA-1, SHA-2, SHA256 and SHA512. These algorithms are computationally intensive.
One known approach to supporting these algorithms is to use a general purpose processor executing general purpose instruction with its general purpose register file. A problem with this approach is that the large amounts of state data which has to be manipulated in performing these algorithms, which typically can generate hash values of 160-bits and upwards, has the result that the operations often have to be split down and performed by a long sequence of individual program instructions operating on parts of the data at a time thereby resulting in a disadvantageous increase in the amount of time required to execute the algorithms and the energy consumed in executing the algorithms.
Another known approach is to provide a special purpose cryptographic support processor, such as a cryptographic coprocessor, which has dedicated circuitry for performing the algorithms and is typically initiated by passing a pointer to the start of the data to be hashed and then waiting to receive the resulting hash value. A problem with this approach is that extra cost and complexity is incurred by the provision of the special purpose cryptographic hardware. Furthermore, problems arise in integrating the operation of the special purpose hardware with the other operations of the device, such as interrupt handling, multitasking and the like, since the special purpose cryptographic hardware is difficult and complex to incorporate within the mechanisms normally provided within the data processing system to deal with such aspects of the operation with the data processing system.

This patent is subject to a terminal disclaimer.


Examples are disclosed that relate to touch-sensitive input devices, systems, and methods for providing user input to a computing device. In one example, a touch-sensitive input device comprises an elongated body and a plurality of force-sensing elements spaced along a length of the body. The touch-sensitive input device also comprises a wireless communication subsystem configured to communicatively couple the input device to the computing device and provide signals from the plurality of force-sensing elements to the computing device.

A variety of input devices, such as smart pens, styluses, and handheld controllers, may be used to provide input to computing devices. Some handheld input devices include buttons or other physical input mechanisms that enable users to provide simple user inputs. However, such devices may not allow users to provide varying or more complex gesture inputs and may have limited locations at which inputs may be received.
SUMMARY
This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. Furthermore, the claimed subject matter is not limited to implementations that solve any or all disadvantages noted in any part of this disclosure.
Examples are disclosed that relate to touch-sensitive input devices, systems, and methods for providing user input to a computing device. In one example, a touch-sensitive input device comprises an elongated body and a plurality of force-sensing elements spaced along a length of the body. The touch-sensitive input device also comprises a wireless communication subsystem that is configured to communicatively couple the input device to the computing device and provide signals from the plurality of force-sensing elements to the computing device.
Another example provides a system comprising a computing device and a touch-sensitive input device configured to be communicatively coupled to the computing device. The computing device comprises a touch-sensitive display, a processor, and a memory storing instructions executable by the processor to display content via the touch-sensitive display. The touch-sensitive input device comprises an elongated body and a plurality of force-sensing elements spaced along a length of the body. The touch-sensitive input device also comprises a wireless communication subsystem that is configured to communicatively couple the input device to the computing device and provide signals from the plurality of force-sensing elements to the computing device.
Another example provides, at a touch-sensitive user input device comprising an elongated body, a method for providing user input to a computing device communicatively coupled to the touch-sensitive user input device. The method comprises receiving signals from a plurality of force-sensing elements that are spaced along a length of the body. The method also comprises determining that the signals correspond to a user input event and communicating the signals to the computing device.


A synthesis procedure learns program transformations for a text document, on-the-fly during an edit session, from examples of concrete edits made during the edit session and from an unsupervised set of additional inputs. The additional inputs are derived from explicit feedback from the user and inferred feedback from the user's behavior during the edit session. A reward score, based on anti-unification and provenance analysis, is used to classify the additional inputs as either a positive input or a negative input. Outputs are generated for the positive inputs that are consistent with the existing examples and then used to synthesize a new program transformation. The program transformations are then used to generate code edit suggestions during the edit session.

Editing source code programs is a task that is performed often during the development and maintenance of a source code program. Developers (e.g., users, programmers) often perform repetitive edits to a program to add new features, repair bugs, or refactor portions of the source code. These repetitive edits are context-specific and can be applied to multiple locations in the source code program having a similar context. Performing these edits manually is tedious and error-prone. To reduce the developer's burden in performing these edits, software tools, such as Integrated Development Environments (IDEs) and static analysis tools, implement transformations for some fixed class of repetitive edits that are frequently encountered, through boilerplate code (e.g., equality comparisons or constructors), code refactoring (e.g., Rename, Extract Method), and quick fixes. However, these transformations are limited and extending them is complicated and time-consuming.
Programming by example is another technique used in some software tools that automates context-specific repetitive edits by learning transformations from past edits. The main challenge to the example-based approach is in generalizing the examples to transformations that produce correct edits on more than the known examples but also on unseen inputs. Generalizing examples of edits to program transformations can lead to incorrect generalizations, that produce a false negative or a false positive. A false negative is where a program transformation does not produce an intended edit in a location that should be changed. False negatives increase the burden on developers to provide more examples or to perform more edits themselves, reducing the number of automated edits. Additionally, false negatives may lead developers to miss edits leading to bugs and inconsistencies in the source code.
A false positive produces an incorrect edit. False positives are often related to transformations that are too general. The proliferation of false negatives and false positives may deter a developer from using a software tool. Hence, finding the correct level of generalization is crucial for the adoption of such systems.

Feedback-driven semi-supervised synthesis of program transformations


Compositions and methods are disclosed for preventing the oxidative corrosion of metal surfaces by exposing a metal surface to an anti-corrosion agent characterized as a lower alkyl carboxylic acid or salts and/or other derivatives that conserve or embody the lower alkyl carboxylic acid moiety present in their molecular structures as an active anti-corrosion agent. The anti-corrosion agent may be used in combination with a material capable of forming a moisture retentive barrier over the metal surface. The compositions and methods of the invention provide a practical, non-toxic way of ensuring anti-corrosion protection for metals, or devices containing exposed metals, stored or operated in water or in the presence of water vapor. Exemplary, non-exhaustive uses of the invention include employing the composition as lubricant for the surface of a metal or as a pump oil or brake fluid; using the composition as an undercoating for painting, electro-plating or electro-polishing procedures; and providing a protective coating for any metal or metal-containing machine or device, form automotive assembly plant metal press machines to electronic circuit boards.

Corrosion is a serious problem that affects and undermines the quality of everyday social life and the endurance of industrial products. Extensive efforts have been undertaken to design and fabricate products such as steam generators, heat exchangers, bridges, oil drilling platforms and motor vehicles that can resist the destructive effects of corrosion. For many traditional products, however, corrosion continues to be a serious destructive problem. In addition to traditional products, new developments in energy sources, advances in material sciences, microprocessing technology and miniaturization of new devices to the micron scale all reassert the demands for effective anticorrosion technologies that avert device failures.
Corrosion is typically understood as an electrochemical reaction that involves loss of electrons from metals, a reaction more generally described as oxidation. The definition of oxidation in electrochemical terms is independent of whether or not oxygen is present when the process of electron loss from a metal occurs. The loss of one or more electrons from a metal requires the acquisition of the electron(s) by another agent. Thus, the metal that serves as an electron donor in this case is termed a reducing agent, while the electron acceptor serves as an oxidizing agent.
One practical example illustrating such an electrochemical event typically involves metallic iron. Electrons lost from an iron atom (reducing agent) can be acquired by oxygen (oxidizing agent) to produce a new combined iron and oxygen derivative identified as iron oxide, or rust, which is an inorganic, low density (flaky) product commonly associated with metal corrosion. Although oxygen is used as a model of iron oxidation in this case, the same oxidizing agent effect could be demonstrated by sulfur and the resulting product could have been iron sulfide instead of iron oxide.
Apart from rust involving metal corrosion, the formation of scale presents another illustrative model tied to principles of oxidation. Scale is defined as a thin coating, layer or encrustation of material that is rich in complex oxides of sulfur, magnesium and/or calcium. These and other insoluble materials are typically developed and observed as mineral deposits on the inside diameters of pipes, chambers or containment vessels when water plus its dissolved constituents, or solutes, are heated in the process of making hot water.
The transfer of electrons between oxidizing agents and reducing agents cannot occur without the presence of an electrically conductive medium. Water typically serves as the electrically conductive universal solvent medium that supports metal oxidation, consequential corrosion and rusting as well as scale formation in the foregoing models.
Efforts to halt water-mediated metal oxidation and corrosion typically rely on superficial passivation of the metal with toxic materials such as chromic acid, sacrificial coatings (e.g., zinc or galvanized coatings), electroplated metals, polymeric coatings or related efforts that produce a protective barrier between the reactive metal surface and water. As another example, light oil treatments have also been used to protect metal surfaces.
Implementation of such strategies usually produces an inflexible anti-corrosion barrier on metal surfaces, and once applied, its removal may be difficult or impossible. In addition, the removal of such coatings can generate potentially hazardous waste materials. For those situations where micro-mechanical or circuit-based devices display corrosion tendencies, aggressive industrial anti-corrosion methods may be totally unsuitable and physically damaging. Thus, there is a significant need for new, simple-to-execute anti-corrosion barrier possibilities.

Lower alkyl carboxylic acid moieties for preventing oxidative corrosion of metals and organoleptic stabilizer for food and beverages