Heating device having a substantially flat heating element with specifically selected physical parameters is provided for heating an object to a required temperature. The physical parameters are selected such as to, at a given power and at a selected voltage supply to the heating element, provide as low as desired temperature gradient between the temperature of the outer surface of the heating element through which heat is dissipated and the required temperature of the object. Heating devices of the invention may be implemented in domestic heaters, in food cooking devices, in medical devices, etc. Also provided is a method for designing heating elements for use in such devices.

The present invention relates to electric heating devices in general and in particular to heating elements useful in such devices.
Heating devices employed for household, industrial or other use have typically a heating element which is embedded within the device and which then transfers heat by radiation, convection or conductance to an output surface of the device. The temperature at the output surface of the device is thus much lower than the working temperature of the heating element. There is usually a very big temperature drop between the temperature of the heating element which ranges from 100""s to 1,000""sxc2x0 C., depending on the type of device, to a temperature at the output surface which may range from 60-90xc2x0 C. for household heating devices to 120-300xc2x0 C. for household cooking and baking devices.
Heating devices come in a large variety of form and shape. For example, one type of electric heating device has a bare heating element typically fashioned as either a band or a wire made from an alloy containing nickel and/or chromium and which typically reaches working temperatures ranging from about 400xc2x0 C. to 1600xc2x0 C. The heat generated by this type of heating elements is dissipated to the surrounding medium by mainly one or any combination of three heat transfer mechanisms, these being radiation, natural or free convection or forced convection (e.g. by the use of a ventilator). Such heating devices enjoy the advantages of being inexpensive, small, of a relatively low weight and having a long lifetime. However, they suffer from a drawback arising out of the high working temperature of their heating elements which poses a safety hazard.
In another type of electric heating device, commonly known as the electric radiator, the hazards associated with the bare heating element type of heating device are eliminated by submerging a heating element in a reservoir of oil or a similar liquid employed for transferring the heat generated by a heating element to the external walls of the radiator. Typically, the output temperature of a domestic heating radiator is about 70xc2x0 C. whereas the working temperature of its heating element is 700xc2x0 C. or above. Consequently, such a domestic heating radiator is typically equipped with heat-insulating means. As is well known, electric radiators suffer from the disadvantages that they are expensive, heavy, and relatively inefficient.
U.S. Pat. No. 2,600,486 discloses an electric heating element which comprises a flexible conducting metal sheet in which slits are cut so as to form an elongated relatively narrow torturous flow path for an electric current. A similar kind of heating device is also disclosed in U.S. Pat. No. 3,584,198. U.S. Pat. Nos. 3,525,850 and 4,551,614 disclose an electric heater comprising elongated heating elements in the form of corrugated matallic ribbons which are heated to a temperature ranging from about 1200xc2x0 F. to 1800xc2x0 F. (about 650-1000xc2x0 C.). U.S. Pat. No. 2,719,213 discloses a heating device in the form of a flat panel which comprises an electric conductor arranged in a plane between two different non-conducting sheets or layers, and French Patent Specification 975,038 discloses a heating element in the form of arrogated plates. Another heating panel is disclosed in U.S. Pat. No. 3,244,858 wherein an electric heating wire is arranged in a plane to track a zig-zag path over both sides of a non-conducting planar core. U.S. Pat. No. 4,203,198 discloses a planar heating device employing a heating element arranged in a plane to track a tortorous path and sandwiched between two sheets of fiber glass. Another heating device with a heating element arranged in a plane between two insulating sheets is also known. U.S. Pat. No. 4,032,751 discloses a planar heating element utilizing electrically conducting carbonaccous pyropolymers. An electric planar heating device intended for use as an electrical bandage is described in U.S. Pat. No. 2,712,591, wherein an electrically conducting ribbon is embedded in a resilient strip of insulating material. A flexible circuit heater which can be used within clothing or the like is disclosed in U.S. Pat. No. 4,948,951, utilizing an electrically conductive strip made to track a torturous path within a flat flexible member. U.S. Pat. No. 4,665,308 discloses an electrical heating element that can be incorporated in the lining of an item of clothing which makes use of a ductile insulated metal wire fixed to a metal sheet.
There is accordingly a need in the art to provide an electric heating device for heating an object to a required temperature that eliminates the need for thermo-insulating means or at least substantially reduces the requirements to such means.
It is an object of the invention to provide a novel heating device with as low as desired temperature gradient between the temperature of the outer surface of a heating element and the required temperature of the heated body.
It is an object in accordance with some embodiments of the invention to provide a heating device wherein the heating element constitutes the heat dissipating, output surface of the device.
It is an object in accordance with some other embodiments of the invention to provide a heating device wherein the heating element is embedded in or forms a structural element of a household object serving also a purpose other than heating.
It is flrhermore an object of the invention to provide domestic enclosure heating devices, electric cooking devices and therapeutic heating devices having characteristics in accordance with the above objects.
It is furthermore an object of the invention to provide a method for designing in constructing such heating devices.
Other objects of the invention will be clarified after reading the text below.
Generally speaking, the present invention provides a method and device capable of a so-called xe2x80x9clow-gradientxe2x80x9d heating. In practice, in most cases it is desired to have substantially low gradient between the surface temperature of a heating device and the temperature of the heating object, so as to reduce the danger of fire, as well as the danger of bums, when applying a heating device to the body for medical purposes. Additionally, such a low-gradient heating enables to reduce the requirements of electro- and thermo-insulation, and to increase the effectiveness of heating (i.e., achieving a desired effect at minimal energy). This means that in order to create a high-quality heating device, its heating element, intended for heating a given object, should be independently designed and calculated, taking into account not only the power required to obtain a desired temperature of the object, but also the fact that the surface temperature of the heating element should be as low as desired different from the required temperature of the heated object. This is a very complicated task, since the transfer of heat from the heating element towards the object is proportional to the temperature gradient (i.e., to the difference between the temperature of the heating element and the temperature of the heated object). Accordingly, the desired decrease of the temperature gradient should be compensated, and practically, the single solution for this is a maximal increase in the surface area of the heating element.
Thus, the main idea of the present invention consists of designing a heating element whose surface temperature and surface area are independently selected at the given power required for heating a given object to a required temperature.
It was found by the inventor, that the solution for the above task is based on directionally varying the ratio between an electric current passing through the heating element and voltages at its input and output circuits. For the purpose of independent control of the surface temperature and surface area of the heating element, materials for the heating element should be selected in accordance with their physical parameters, namely, the specific resistivity and dimensions of the heating element, wherein the latter is in the form of a planar band having a substantially rectangular cross-section.
The inventor has found that in order to obtain the required effect, i.e., independent control of the surface temperature and surface area of the heating element at a given power, the width, b, and length, l, of the heating band should be selected so as to satisfy the following relations:       b    ≥          k      ·      I      ·                        ρ          δ                          l    ≥          k      ·      U      ·                        δ          ρ
wherein I and U are the electric current (A) and voltage (V) of the heating element; xcfx81 is the specific resistivity (Ohmxc2x7mm2/m); k is the so-called xe2x80x9ccorrection coefficientxe2x80x9d selected in accordance with the following two considerations: first, the value of k should be increased in those cases, when the surface area and the surface temperature of the heating element should be, respectively, increased and decreased; second, k should be of the same magnitude in the above equations, wherein the length units are meters, and the width and thickness units are millimeters.
The physical sense of the above equations will now be explained. The relationship between the heat power rating W of an electric heating element and its surface area S required to dissipate the heat generated thereby, can be approximated by the following equation:
S=k1W
Here, k1 is the coefficient that depends on a variety of factors, including the surface temperature of the heating element, the medium surrounding the heating element (e.g., air, water or another fluid), the ambient temperature of the surrounding medium, and to a lesser degree, the location of the heating device within its local environment, and the like. As such, the values of k1 can be obtained empirically by an artisan for various specific cases. For example, it is known that an electric heating element having a surface temperature of about 70-90xc2x0 C. requires about 0.7-0.8 m2 surface area to dissipate 0.5 Kwatt in an environment having an ambient temperature of 20xc2x0 C.
According to the invention, the heating element is a planar band having a length l along which the potential U falls, and a generally rectangular cross section having a width b and a thickness xcex4. As such, the heating element has one or two major surfaces (as the case may) each having an area lb, through which heat is dissipated. The surface area S of the heating element can be approximated by the following equation:
S=k2bl
wherein k2 is a coefficient which is approximately equal to 1 or to 2, depending on the number of surfaces through which heat is dissipated.
As is well known, the power rating W of an electric device, for example, an electric heater, is defined as the product of an operating potential U and an operating current I, i.e., W=IU. The operating potential U is equal to the product of the conductor""s operating current I and electrical resistance R, i.e., U=IR. Further, the electrical resistance R of a conductor depends on the specific resistivity of an electrically conductive material from which the conductor is fabricated and the physical dimensions of the conductor, in accordance with the following equation: R=xcfx81l/A. Here, xcfx81 is the specific resistivity of the electrically conductive material, l is the length of the conductor, and A is the cross-sectional area of the conductor, i.e., A=bxcex4.
Thus, from the above equations, we have:
W=I2R;W=U2/R
S=k1I2R;S=k1U2/R;S=k1I2xcfx81l/bxcex4S=k1U2bxcex4/xcfx81l
Hence,
k2bl=k1I2xcfx81l/bxcex4k2bl=k1U2bxcex4/xcfx81l
The length l and width b of the heating element can now be expressed as follows:       l    =                                                      k              1                                      k              2                                      ·        U                                    δ          ρ                          b    =                                                      k              1                                      k              2                                      ·        I                                    ρ          δ
It is thus understood that k=(k1/k2)xc2xd.
To more clearly illustrate the essential features of the present invention, let us consider the following example of designing a heating element of a heating device intended for use in physiotherapy. Assume that the surface temperature of the heating element has to be in the range of 41-43xc2x0 C. From experimental results, it appears that the coefficient k equal to 2 corresponds to this temperature value. A band of stainless steel with the thickness xcex4 of 0.05 mm and specific resistivity xcfx81 of 0.7 Ohmxc2x7mm2/m is selected as an electrically conductive material for fabricating the heating band. It is known that, in this specific application (i.e., physiotherapy), the power to be transferred to an object to be heated (i.e., a patient""s body) is about 50 Watt. Let us consider two possible cases: (1) The selected voltage U is 10V, and consequently, the electric current I is 5A; and (2) the voltage U and current I are, respectively 5 V and 10A.
Hence, for the first case, we have:       b    1    =                    2        ·        5        ·                              0.7            0.05                              ≈              37.4                          xe2x80x83                        mm                          xe2x80x83                                  l          1                      =                  2        ·        10        ·                              0.05            0.7                              =              5.4                          xe2x80x83                        m
The surface area S1 of the heating element through which heat is dissipated is calculated as follows:
S1=b1xc2x7l1=37.4 mmxc2x75.4 m=2xc2x7105 mm2
For the second case we have:       b    2    =                    2        ·        10        ·                              0.7            0.05                              ≈              74.8                          xe2x80x83                        mm                          xe2x80x83                                  l          2                      =                  2        ·        5        ·                              0.05            0.7                              ≈              2.7                          xe2x80x83                        m
The surface area S2 of the heating element through which heat is dissipated is calculated as follows:
S2=b2xc2x7l2=2xc2x7105 mm2
It is thus evident that, the variation of the ratio between the electric current I and voltage U, with the given constant power and with the constant surface area of the heating element (i.e., with the fixed temperature), enables to control the geometry of the heating element, namely, to control the ratio between the length and width of the heating element.
If the temperature of the heating element has to be changed with the same power, it can be achieved by selecting an appropriate value of the coefficient k, keeping in mind that an increase in the value of k leads to an increase in the surface area S, and, consequently, leads to a decrease in the surface temperature of the heating element.
The ratio between the length and width of the heating element can be affected by the selection of an appropriate electrically conductive material. As follows from the above equations, under the fixed values of current and voltage, the higher the specific resistivity xcfx81 of the heating element and the lower its thickness xcex4, the higher the length l of the heating element and the lower its width b.
Thus, the present invention allows for simultaneously and independently controlling the temperature and geometry of a heating element. This is a new approach, which has never been used for designing heating elements. According to this approach, initially, parameters defining the requirements of a specific application are set, namely, the power for heating a given object to a required temperature, and the voltage to be supplied to the heating element in accordance with a predetermined application of the heating device. It should be understood that these parameters, i.e. power and voltage, are defined independently. Then, the surface area of a heating element through which this power is to be dissipated is determined, and the physical parameters of the heating element (length, width, thickness and specific resistivity) are selected to meet the requirements of the specific application.
The present invention relates to domestic, industrial and other heating devices suitable for a wide range of applications including, but not limited to, heating enclosed spaces, heating food, therapeutic purposes and the like, and relates to electric heating elements for use therewith.
In the following, the term xe2x80x9cheating devicexe2x80x9d will be used at times. This term should be construed in a broad manner mainly to relate to any device or object wherein one or its intended uses is heating. In accordance with the prior art, a heating device is typically a dedicated device designed for a single function, namely heating. However, in accordance with the invention, by some embodiments thereof, the heating device is embedded in or forms parts of objects having an entirely different purpose. For example, the heating element may form a structural component in a piece of furniture thus having a dual role in such an object. Thus, the term xe2x80x9cheating devicexe2x80x9d should be understood, depending on the context, as referring also to such dual-role objects.
The present invention allows in fact to design heating elements for every purpose, need and in any desired form. This unique feature of the invention allows to incorporate the heating element as a structural element or as an add-on element in a large variety of objects, including various domestic constructional units (e.g. door frames) furniture, etc.
The heating element of the invention dissipates heat at practically any desired power rating, with a working temperature of the element which is way below the working temperature of the heating element of prior art devices operating with a comparable power rating. For example, in a heating device of the invention suited for domestic interior heating, the 4V heating element may be designed to operate with a working temperature of 70-80xc2x0, which is the conventional output temperature of heating devices, and accordingly, the heating element may be placed and form the external, output surface of the heating device.
In order to avoid electric shock hazards, the heating element of the invention may be designed to operate under relatively low voltage, ranging, depending on the application, between 1V and 24V (which is the conventional upper limit in low voltage systems).
In accordance with the present invention, the heating element to suit a specific application is designed on the basis of novel developed relationships which allow to match the physical parameters of the heating element (dimensions and specific resistivity), to the electrical parameters of the heating element (desired voltage and power rating). These relations allow to choose the appropriate heating element to suit a specific application. Given the fact that the heating element operates at a relatively low temperature, it may be made from a wide variety of alloys, which cannot be used in conventional (prior art) heating devices, such as aluminum, stainless steel, copper, etc.
According to the general teaching of the invention, there is thus provided a heating device for heating an object to a required temperature, the heating device comprising a heating element and a power source for supplying voltage to the heating element, wherein:
the voltage U to be supplied to the heating element is selected in accordance with a predetermined application of the heating device;
the heating element is made of a selected electric conductive material of a specific resistivity xcfx81, is substantially flat, and has a substantially rectangular cross section, so as to define at least one major outer surface through which a given heating power required for heating said object to said required temperature is dissipated, length l, width b and thickness xcex4 of the heating element being selected such as to satisfy the following relations:       b    ≥          k      ·      I      ·                        ρ          δ                          l    ≥          k      ·      U      ·                        δ          ρ
xe2x80x83wherein I is the electric current passing through the heating element; xcfx81 is the specific resistivity (Ohmxc2x7mm2/m); xcex4 is the thickness of the heating element in millimeters; k is a correction coefficient providing the units of length and width in meters and millimeters, respectively, and selected such that an increase in the value of k results in an increase in the surface area of the heating element and decrease in the surface temperature of the heating element;
the heating device thereby providing a desired temperature gradient between said at least one major surface of the heating element and said required temperature.
Where the electric heating device is employed to heat air at an initial ambient temperature of about 20xc2x0 C. (room temperature) to a temperature of 100xc2x0 C. or more, or to heat a water based medium consisting of at least 50% water which is initially at room temperature, to a temperature up to about 50xc2x0 C., k will preferably be within the range of 0.2-0.6.
In case the heating device of the invention is employed to heat air at room temperature to a temperature of up to about 90xc2x0 C. or less, k will preferably be above 0.6.
The present invention allows to design a heating element to suit, practically, any desired need. At times, the length and width of the elements are predetermined by the shape of the heating device, leaving a certain degree of freedom in the choice of alloy (and hence of the specific resistivity xcfx81) and thickness of the element. This may be the case, for example, in heating devices in which the heating element is incorporated in another object, e.g. a piece of furniture. In other cases, the material and hence the specific resistivity xcfx81 is predetermined, leaving a degree of freedom for other physical parameters, being one of the length, width and thickness. This may be the case, for example, in heating devices where the heating element is intended to come into direct contact with a food item where the alloy from which the heating element is made will typically be stainless steel. These are only examples, but it is clear that it is possible, for practically all applications, to find, based on the above relations for length and width, a combination of parameters which allow to design an appropriate heating element, namely, a heating element which provides as low as desired temperature gradient between the outer surface of the heating element and the required temperature of the heated body.
By a specific aspect of the invention there is provided a heating device comprising a heating element incorporated as a structural element in a stationary object such as a piece of furniture, door or window frames, etc. In accordance with a further specific aspect of the invention, there is provided a heating device comprising a heating element embedded in or enclosed within such a stationary object.
Another specific aspect of the invention concerns a device for food heating. The term xe2x80x98food heatingxe2x80x9d should be understood as referring to one of a variety of heat-based food processing techniques including cooking, baking or grilling.
The novelty in the cooking device of the invention is in that it comprises a metal body which is either in contact with food or which is in proximity with food without any object between it and the food, said metal body serving as a heating element being thus connected to a power source for passing heating electric current therethrough.
In accordance with one embodiment of this latter aspect, there is provided a cooking device for heating of liquid food, comprising a metal vessel for holding the food having metal walls serving as heating elements, and comprising a power source for passing low voltage, high electric current therethrough, thereby heating the liquid food contained therein. The electrical current parameter useful for such an application is typically voltage ranging from 1.0V to 12V with a power rating of 1-2 KWatt.
In accordance with another embodiment of the latter aspect, there is provided a device for heating solid food items, in which the solid food items are placed in direct contact with a metal plate, said metal plate serving also as a heating element and being connected to an electric power source for passing a heating electric current therethrough.
In accordance with yet another embodiment of the latter aspect, there is provided a device for heating food by means of heat irradiation onto the food, comprising a food-containing enclosure having one or more metal walls, at least one of said metal walls serving as a heating element to heat said enclosure and being connected to a power source for passing a heating electric current therethrough.
By a further aspect, the present invention provides a heating device adapted to be worn or held on a body part for heating of that body part. By one embodiment of this aspect, such a device comprises a cloth or a cloth base matrix with a heating element embedded therein, the heating element having the above specifications. In accordance with another embodiment, the device comprises a liquid or gel-containing enclosure having pliable walls and containing therein a heating element, being a heating element having the above characteristics.
By yet another aspect of the invention, there is provided a method for designing a substantially flat heating element having a substantially rectangular cross-section for implementing into a heating device for a predetermined application consisting of heating an object to a required temperature, the method comprising the steps of:
(a) defining a power rating W in accordance with the predetermined application;
(b) defining a range of operating potential U of the heating element in accordance with the predetermined application;
(c) selecting physical parameters of the heating element, so as to dissipate therethrough a heating power substantially equal to said power rating W, when the operating potential U falls onto the heating element, thereby providing a desired temperature gradient between the temperature of an outer surface of the heating element through which power is dissipated and said required temperature, wherein the selecting of the physical parameters comprises:
selecting an electrically conductive material with a specific resistivity xcfx81 for fabricating therefrom said heating element, and selecting dimensions of the heating element, so as to satisfy the following       b    ≥          k      ·      I      ·                        ρ          δ                          l    ≥          k      ·      U      ·                        δ          ρ
xe2x80x83wherein I is the electric current passing through the heating element; xcfx81 is the specific resistivity (Ohmxc2x7mm2/m); l is the length of the heating element in meters; b is the width of the heating element in millimeters; xcex4 is the thickness of the heating element in millimeters; k is a correction coefficient providing the units of length and width in meters and millimeters, respectively, and selected such that an increase in the value of k results in an increase in the surface area of the heating element and a decrease in the surface temperature of the heating element.
It will be appreciated that the actual working temperature in a heating device depends on a variety of factors, including the nature of the heating device environment, the exact geometry, etc., and therefore it is not always possible to predict the working temperature entirely on theoretical considerations.
Owing to the fact that the voltage to be supplied to the heating element is a varying parameter selected in accordance with a specific application, a step-down transformer should be used in a heating device according to the invention. However, at the frequencies of the existing power networks (i.e., 50 Hz and 60 Hz), the weight and dimensions of such a transformer are significantly high, which sometimes makes the use of the transformer inefficient. The development of modem inverters practically allows for eliminating weight and dimensions related problem, since the weight and dimensions of a transformer are in inverse proportion to the working frequency thereof.
The heating band according to the invention, due to its task, occupies a significantly large area, and consequently, the induction C of its electric circuit will be significantly high. On the one hand, since the inductive resistance, Rc, is proportional to the frequency f (Rc=kf), this problem must be overcome. On the other hand, due to the substantially large area and relatively high electric currents (as compared to those flowing in conventional heating devices), the heating band may behave like an antenna that produces an electromagnetic field presenting noise for electronic equipment in its vicinity.
The present invention also provides the solution for the above problem. This is implemented by accommodating wires connecting the heating band to a power source in the following manner. One of the wires is connected directly to one of the outputs of the heating band. The other wire, on its way to the other output of the heating band, passes along the entire circuit of the band so as to be substantially symmetrical to the band along its longitudinal axis. This enables to sharply reduce both the inductive resistance and the electromagnetic field.
Another problem arises when the condition for obtaining low-gradient heating is associated with the need to work with substantially high electric currents, and consequently, substantially low voltages. Hence, the wire connecting the power source to the heating element has to be made with a substantially high cross section, which may affect the flexibility of the wire and thus may be undesirable in some applications (e.g., physiotherapy). This problem can be solved in the following manner. Since the weight and dimensions of a transformer operating with high frequencies are significantly low, an output transformer can be taken out of the inverter and mounted in a heating element. As a result, a substantially low electric current flows through the wires connecting the power source to the heating element, thereby providing desired flexibility of the electrically conductive wires.
The case may be such that the supply of 220V or 110V to the heating element is undesirable for industrial safety provisions. In this case, an intermediate transformer reducing the voltage to 12V will function inside the inverter, while a transformer reducing the voltage to 1V and less will function inside the heating element. By this, the problem associated with the need to operate with substantially high currents, and consequently, relatively low voltages, can be solved.

Bar-Keser Project Management Initiatives and Economic Consultants


Extracts from an indigenous Jamaican plant that exhibit an anti-tumor activity and/or an anti-inflammatory activity and, more particularly, an extract of Jamaican Ball Moss (Tillandsia Recurvata) that has a therapeutic pharmacological activity, in particular an anti-cancerous activity by inducing tumorous cell death by apoptosis, and active compounds isolated thereof are described. Furthermore, methods for the extraction of the extracts are disclosed. Also, a pharmaceutical composition or product for the treatment of cancer which includes an effective amount of the described extract or an active compound thereof, a therapeutic compound and optionally a pharmaceutical acceptable carrier are described.

1. Field of the Invention
The present invention relates to a therapeutic extract derived from plant biomass for use in regressing cancerous tumors and/or for anti-inflammatory effect and, specifically, to a pharmacologically active compound extracted from the indigenous Jamaican plant Ball Moss (Tillandsia Recurvata) that has beneficial activity principally in destroying cancer cells.
2. Description of the Background
There is great growth in the overlapping fields of biology, technology, and medicine, including remarkable advances in cellular biology that have given a new understanding of the molecular basis for some diseases. Nevertheless, the incidence of some forms of cancer continues to rise. This is particularly true of breast cancer, a leading cause of death in women. Considerable effort has focused on the early detection of cellular transformation and tumor formation in breast tissue.
The increased focus on cellular biology has led to a profusion of drugs to treat cancer patients are drugs, which more or less directly target the growth mechanism. These drugs include alkylating agents, intercalating agents, antimetabolites, etc., most of which target DNA or enzymes regulating the DNA duplication and elongation process. However, rapidly growing tumors do not always exhibit high levels of cell proliferation, but may also exhibit low levels of cell death compared to the normal cell population from which these tumor cells issue. For these types of rapidly growing tumors, the mentioned drugs are not effective. In addition, the great majority of the drugs currently available for treatment of cancer are toxic and involve detrimental side-effects on healthy cells, tissues and organs.
The high-technology approach has obfuscated many promising therapeutic drugs derived from natural origins. A successful anticancer drug should kill or incapacitate cancer cells without causing excessive damage to normal cells. This ideal situation is achievable by inducing apoptosis in cancer cells without undue side effects, and organic drugs are well-suited. Apoptosis is a programmed cell death initiated by the nucleus. Apoptosis is a mechanism of cell death that incurs little or no inflammatory response. Currently, radiation is effective in producing cell death by apoptosis but is dependent on dose rate as well as ionization density, and this subjects other non-tumor cells to radiation risks.
Natural products are the most consistently successful source of drug leads. They are likely to continue to be sources of new commercially viable drug leads. Plants supply most of the active ingredients of traditional medicinal products. Advances in the treatment of cancer will require the continued development of novel and improved chemotherapeutic agents.
Therefore, there remains a need in the art for finding organic anti-cancer drugs that overcome at least some of the above-mentioned drawbacks.

Anti-tumor and anti-inflammatory extracts of plant biomass and their uses


Novel bisphenol carboxylic acid tertiary ester derivatives having two aromatic ether groups and an ester group which are all replaced by acid labile groups are provided. The derivatives are used as a dissolution inhibitor in a chemically amplified positive resist composition comprising an organic solvent, an alkali soluble resin, and a photo-acid generator. Since the dissolution inhibitor has a highly reactive acetal group as an acid labile group, its coupling-off rapidly takes place after exposure. The dissolution inhibitor itself is less alkali soluble and its acid decomposition product is a phenol derivative having a carboxylic acid group with high alkali solubility, leading to a high dissolution contrast.

1. Field of the Invention
This invention generally relates to a chemically amplified positive resist composition which is highly sensitive to actinic radiation such as deep-UV, electron beam and X-ray, can be developed with alkaline aqueous solution to form a pattern, and is thus suitable for use in a fine patterning technique. More particularly, it relates to a bisphenol carboxylic acid tertiary ester derivative which is useful as a dissolution inhibitor in such chemically amplified positive resist compositions.
2. Prior Art
As the LSI technology tends toward higher integration and higher speed, further refinement of pattern rules is required. The current patterning technology mostly relies on light exposure which is now approaching the essential limit of resolution which is dictated by the wavelength of a light source. It is generally recognized that in light exposure using g-line (wavelength 436 nm) or i-line (wavelength 365 nm) as a light source, a pattern rule of about 0.5 .mu.m is the limit. For LSIs fabricated by such light exposure technique, a degree of integration equivalent to 16 mega-bit DRAM is the limit. At present, LSIs fabricated in the laboratory have reached this stage. It is urgently required to develop a finer patterning technique.
Under such circumstances, deep-ultraviolet lithography is regarded promising as the next generation of fine patterning technology. The deep-UV lithography is capable of working on the order of 0.3 or 0.4 .mu.m. If a less light absorbing resist is used, it is possible to form a pattern having a side wall nearly perpendicular to the substrate. Attention is now paid to the technique of utilizing a high illuminance KrF excimer laser as a light source for deep-UV. In order that an excimer laser be utilized in mass-scale manufacture, a resist material featuring low light absorption and high sensitivity is desired.
Chemically amplified, positive working resist materials using acid catalysts were recently developed as disclosed in JP-B 27660/1990, JP-A 27829/1988, U.S. Pat. No. 4,491,628 and No. 5,310,619. These materials have high sensitivity, resolution and dry etching resistance and are promising as resist materials especially suited for deep-UV lithography.
With respect to the chemically amplified positive resist materials, it is known that their function is largely governed by the dissolution inhibitor used. One typical example of the known dissolution inhibitors is given below. ##STR1##
This compound itself is an oil soluble compound. When it is blended as one component of resist material, it serves for three functions of reducing the solubility of the resist material in aqueous base, suppressing film thinning upon development, and in exposed areas, releasing an acid-labile group in the presence of an acid generated so that the resist material becomes soluble in an alkaline developer to increase the dissolution rate of exposed areas.
Chemically amplified positive resist materials using the above-specified compound as a dissolution inhibitor, however, fail to provide high resolution upon alkaline development and undergo profile deterioration due to scum generation. The following two facts account for these drawbacks.
First, decomposition of an acid-labile group is insufficient even after exposure. In the above-specified compound, the acid-labile group which protects phenol is a tert-butoxycarbonyl group. Since this protective group has relatively low acid lability, acid decomposition can be insufficient even after exposure when the above-specified compound is combined with particular resist components.
Secondly, the difference in alkali dissolution rate between the above-specified compound and its acid decomposed product is not so significant. It is noted that the ratio of alkali dissolution rate of the latter to the former is referred to as a dissolution contrast. Since the acid decomposed product of the above-specified compound is a phenol derivative, its increase of dissolution rate in aqueous base is insufficient as compared with carboxylic acid derivatives.
JP-A 167811/1994 discloses a dissolution inhibitor of a similar structure to formula (1) to be defined below in which the hydrogen atom of carboxylic acid is replaced by an alkoxyalkyl, cyclic ether, vinyloxyalkyl or tert-alkoxycarbonylalkyl group. This dissolution inhibitor, however, is unstable in resist material in the presence of a phenolic alkali-soluble resin (that is, under faintly acidic conditions).

Bisphenol carboxylic acid tertiary ester derivatives and chemically amplified positive resist compositions


A glazing made of at least one glass layer and at least one transparent layer of ionomer resin, wherein at least a portion of one face of the at least one transparent layer of ionomer resin is adhered to at least a portion of one face of another layer of the glazing using at least one metal chelate, preferably a metal chelate based primer composition, and the primer composition for use in such a glazing are described, to provide laminated glazings which have improved chock resistance, good optical properties, improved resistance to lamination even during cutting operations, and is economical to produce.

1. Field of the Invention
The present invention relates to a laminated glass (glazing) comprising at least one layer (sheet) of transparent glass and at least one transparent layer (sheet) of ionomer resin, where one of these layers is at least partly coated with a primer, and the primer used to make the glazing.
2. Discussion of the Background
Laminated glasses are frequently used in the building industry and in the transportation industry as glass having "protection security" characteristics and for reducing the probabilities of breakage and accidents by shock. One conventional example of laminated glass particularly resistant to shock, is a laminated glass containing at least one layer of glass and at least one layer of polycarbonate. However, those glasses have significant problems in adhering the polycarbonate onto the glass or cracking (due to the difference between thermal expansion coefficients) when the glass and the polycarbonates are directly connected. One method to remedy those problems, has been to insert between the glass and the polycarbonate at least one layer of polyurethane. However, the use of such material considerably increases the cost of the product.
Another less expensive laminated glass used in the same type of applications contains a layer of glass and a transparent layer of ionomer resin. Such a laminated glass has been described in the patents EP-191,088, U.S. Pat. No. 4,619,873, U.S. Pat. No. 4,732,944, U.S. Pat. No. 4,906,703 and EP-483,087. In order to increase the adhesion between the glass and the layer of ionomer resin, it is known to prime the glass' surface with a coupling agent, such as a silane, organic amine (aliphatic amine, ethanolamine . . . ) or diisocyanate, before applying the layer of ionomer resin. However, these coupling agents can sometimes be insufficient to provide adequate adhesion between the glass and ionomer resin, with delamination possibly occurring during processing such as cutting operations of the obtained laminated glazing. Thus, there is a need to further increase the adhesion between the ionomer resin layers and the substrates, notably the glass substrates, which are associated with them in the laminated glazings.

Laminated glass and primer used for its production


A plurality of semiconductor devices provided on a silicon carbide substrate are provided with electrode layers, respectively. The silicon carbide substrate is cut at a region of an exposed surface of the silicon carbide substrate that separates the electrode layers to individually separate the semiconductor devices. A stress relaxation resin is applied to each individually separated semiconductor device to cover the exposed surface at a peripheral end portion of that surface of the semiconductor device which has the electrode layer thereon. A semiconductor apparatus can thus be obtained that also allows a semiconductor device with a silicon carbide or similar compound semiconductor substrate to adhere to a sealant resin via large adhesive strength and thus allows the sealant resin to be less crackable, less peelable and the like by thermal stress caused in operation.

A semiconductor apparatus that employs a power semiconductors device includes that having a semiconductor device sealed with epoxy resin or a similar thermosetting resin, i.e., a mold sealed type, and that having a semiconductor device sealed with gelated resin, i.e., a gel sealed type. In particular, the mold sealed semiconductor apparatus is small in size and excellent in reliability, and handleable, and it is thus used widely for controlling air conditioners and the like. Furthermore, in recent years, it is also used to control an automobile's motive power to drive a motor.
Normally, a semiconductor device is produced as follows: a large number of semiconductor devices provided on a semiconducting crystal substrate (hereinafter referred to as a semiconductor substrate) are diced into individual pieces (or chips). A semiconductor device receiving high voltage exceeding several hundreds volts for operation, seeks insulation between an upper electrode pad serving as a major electrode and a metal frame's side, and accordingly, the upper electrode pad is surrounded by an insulating film formed of a resin material. Note, however, that the semiconductor devices are diced with a dicing blade, and to avoid clogging the dicing blade, the insulating layer is not provided in the dicing region. The semiconductor device is bonded to the metal frame, and thereafter wired and sealed with thermosetting resin, and a semiconductor apparatus is thus completed.
When the above semiconductor apparatus is in operation, the semiconductor device generates heat, which causes thermal stress between the semiconductor device and the sealant resin. This thermal stress is caused as the semiconductor chip and the sealant resin have their respective coefficients of thermal expansion with a difference therebetween, and the thermal stress is also caused as the sealant resin sets and thus shrinks. Normally, the semiconductor device is a square semiconductor chip and has four corners with their ends experiencing maximum stress, and accordingly, may have the four corners defectively peeled off at an adhesive interface.
A conventional semiconductor apparatus has a semiconductor chip exposed in a dicing region covered with a silane based resin film to allow the chip to adhere to a sealant resin via enhanced adhesive strength.

Semiconductor apparatus and method for producing the same


An intrusion detection system employs a pointer fingerprint method for detecting attempted or successful intrusions into an information system or network. In a pointer fingerprint method, the specific stream of bits searched from the traffic streams is a pointer or part of it that must be included in all working buffer overflow (bof) attacks. This makes it possible to detect also the previously unknown bof attacks.

Intrusion detection systems (IDS) are systems that try to detect and alert on attempted or successful intrusions into an information system or network, where the intrusion is considered to be any unauthorized or unwanted activity on that system or network.
Buffer overflows (BOFs) in user input dependent buffers have become one of the biggest security hazards on the Internet and to modern computing in general. This is because such an error can easily be made at programming level, and while invisible for the user who does not understand or cannot acquire the source code, many of those errors are easy to exploit.
The principle of exploiting a buffer overflow is to overwrite parts of memory, which aren't supposed to be overwritten by arbitrary input, and making the process execute this code. To see how and where an overflow takes place, lets take a look at how memory is organized.
In the following one type of a BOF attack is explained in more detail. It should be appreciated that this is only an example and the details of the attack may vary from one attack to another. For example, the pointer may be some other pointer than a pointer to stack address space. (Below a term stack pointer is used for referring to a pointer to stack address space.) Memory addresses can be physical addresses of the memory or virtual/logical addresses used by processes running in a computer. A page is a part of memory that uses its own relative addressing, meaning the kernel allocates initial memory for the process, which it can then access without having to know where the memory is physically located in RAM. The processes' memory consists of three sections: The address space of processes is divided into at least three regions: Code, Data, and Stack. Data in the code segment are machine instructions that the processor executes. The code execution is non-linear, it can skip code, jump, and call functions on certain conditions. Therefore, we have a pointer called EIP, or instruction pointer. The address where EIP points to always contains the code that will be executed next. The data region is a memory space for variables and dynamic buffers. Static variables are stored in this region. The stack is a contiguous block of memory containing data and possibly also some executable code. The bottom of the stack is at a fixed address and fixed size of memory is allocated for the stack. How much of this memory space is used, is dynamically adjusted by the kernel at run time. Depending on the implementation the stack will either grow down (towards lower memory addresses), or up. The stack has the property that the last object placed on the stack will be the first object removed. This property is commonly referred to as last in, first out queue, or a LIFO. The stack consists of logical stack frames that are pushed when calling a function and popped when returning. A stack frame contains the parameters to a function, its local variables, and the data necessary to recover the previous stack frame, including the value of the instruction pointer at the time of the function call address after the stack. The CPU implements instructions to PUSH onto and POP off of the stack. PUSH adds an element at the top of the stack. POP, in contrast, reduces the stack size by one by removing the last element at the top of the stack. A register called the stack pointer (SP) points to the top of the stack. The stack pointer (SP) is also implementation dependent. It may point to the last address on the stack, or to the next free available address after the stack.
A buffer is simply a contiguous block of computer memory that holds multiple instances of the same data type. A buffer overflow is the result of stuffing more data into a buffer than it can handle, i.e. to overflow is to flow, or fill over the top, brims, or bounds. Buffer overflow (bof) is also a term used for a programming error that enables miss-use of a program in such a way that program overwrites some data in the memory. Buffer overflow attack (bof-attack) is a way to exploit bof-weakness in program to execute arbitrary code or to alter the control flow in a malicious manner in a target system where the code is running.
Shell code is simply machine instructions, which we write on the stack and then change the return address to return to the stack. Using this method, a code can be introduced into a vulnerable process and then execute it right on the stack. The return address can be changed to point to a shell code put on the stack by, for example, adding some NOP (no operation) instructions before the stack. As a result it is not necessary to be 100% correct regarding the prediction of the exact start of our shell code in memory (or even brute forcing it). The function will return onto the stack somewhere before our shell code and work its way through the NOPs to our new return address and run our code on the stack.
General fingerprinting is used in most of intrusion systems that use fingerprinting as one of their intrusion detection methods. It is usually a simple pattern matching which searches for some piece of publicly known attack (piece of shell code or whole attack code). There are some weaknesses in these prior art IDS methods. Firstly, because it is possible to write bof-attack (shell code- and nop-part of bof-attack) for exploitable service in many ways (bof-attacks do not resemble each other), general fingerprinting is not sufficient method for detecting bof-attacks. Secondly, it is a heavy operation to process huge amount of data to be analysed because of the large size of the fingerprint. In the prior art methods a bit sequence in data packet has been compared to a high number of long fingerprint patterns. On the other hand, due to the long fingerprint patterns, there have typically not been needs for comparing the fingerprints to "many points" in the bit stream in the data packet. However, since the number of the different fingerprints to be checked is very high (equal to different known attack types), much processing capacity is used. So there is need for a better technique to find both publicly known and yet unknown bof-attacks in a TCP stream.


A PWM (Pulse Width Modulation) signal outputting circuit includes a counting unit for counting a number of clocks to output a counter value, and for resetting the counter value to resume counting when a reset signal is input to the counting unit; a dead time value storage unit for storing a dead time value; and a plurality of PWM signal outputting units for setting a start setting value and a termination setting value. The PWM signal outputting unit generates a termination signal and a start signal. Further, the PWM signal outputting unit is configured to output a PWM signal, which is raised according to the start signal generated by itself and is decreased according to the termination signal generated by itself. Further, the PWM signal outputting units is configured to generate the termination signal when the counter value matches to the termination setting value generated by itself.

The present invention relates to a PWM (Pulse Width Modulation) signal outputting circuit and a method of controlling an output of a PMW signal. More specifically, the present invention relates to a PWM signal outputting circuit and a method of controlling an output of a PMW signal capable of efficiently adding a dead time (a period of time during which each PMW signal is not turned on simultaneously) to each PWM signal having a cyclic period and a duty arbitrarily defined thereto.
In general, a PWM (Pulse Width Modulation) signal has been used for controlling an IGBT (Insulated Gate Bipolar Transistor) and the like disposed for controlling an inverter circuit of an IH (Induction Heating) cooking device and a non-power outage power source device.
For example, an inverter circuit disposed in the IT cooking device is formed of two switching elements, so that the two switching elements are controlled to turn on and off through the PWM signal. In the inverter circuit with such a configuration, when the two switching elements are turned on simultaneously, a through current may flows, thereby causing damage in an inverter control circuit.
In order to prevent the inverter control circuit from being damaged, Patent References 1 to 3 have disclosed technologies, in which an inverter control micro-computer is configured to output a PWM signal with a dead time.    Patent Reference 1: Japanese Patent Publication No. 2004-187492    Patent Reference 2: Japanese Patent Publication No. 2004-357450    Patent Reference 3: Japanese Patent Publication No. 2007-202329
For example, according to Patent Reference 1, a semiconductor device is configured to generate a mutually compensated PWM signal for controlling an inverter circuit. The semiconductor device has a configuration that is configured to make it possible to easily and flexibly add a period of time during which each PMW signal is not turned on simultaneously (the dead time) relative to each of the two PWM signals.
More specifically, the semiconductor device disclosed in Patent Reference 1 includes a first mutually compensated PWM signal generation unit for generating a first PWM signal and a second PWM signal as an inverted signal of the first PWM signal, and a dead time adding unit for adding a first dead time when the first PWM signal is raised and a second dead time when the second PWM signal is raised. Further, the dead time adding unit is configured to be capable of setting the first dead time and the second dead time individually.
Further, in the semiconductor device disclosed in Patent Reference 1, the dead time adding unit includes a dead timer, a first dead time setting register, and a second dead time setting register. Accordingly, the dead time adding unit is configured to be capable of adding a period of time that a value of the dead timer reaches a setting value of the first dead time setting register as the first dead time when the first PMW signal is raised. Further, the dead time adding unit is configured to be capable of adding a period of time that the value of the dead timer reaches a setting value of the second dead time setting register as the second dead time when the second PMW signal is raised.
With the configuration of the dead time adding unit described above, it is possible to set the different dead times relative to the PWM signal and the inverted signal thereof. Accordingly, it is not necessary to change and set the optimal value of the dead time in the semiconductor device. At the same time, it is possible to individually set the optimal dead time, thereby making it possible to accurately control the inverter circuit without increasing power consumption.
In the semiconductor device disclosed in Patent Reference 1, however, it is difficult to solve the following problems.
For example, the semiconductor device includes an IC (Integrated Circuit) for outputting the PWM signal. However, the IC is not necessarily configured to output the mutually compensated signals (the signals with the inverted phases). The IC is desired to have a configuration capable of controlling two phases regardless of outputting the mutually compensated signals or totally different signals. To this end, it is necessary to configure the IC to be able to arbitrarily control a cyclic period and a duty.
A conventional PWM signal outputting circuit will be explained next with reference to FIGS. 1 and 2. The conventional PWM signal outputting circuit has a configuration capable of arbitrarily controlling the cyclic period and the duty relative to each of a plurality of PWM signals.
FIG. 1 is a block diagram showing the configuration of the conventional PWM signal outputting circuit capable of arbitrarily controlling the cyclic period and the duty. FIG. 2 is a timing chart showing an example of an operation of the conventional PWM signal outputting circuit.
As shown in FIG. 1, the conventional PWM signal outputting circuit is formed of, for example, a semiconductor device such as a micro-computer and the like. The conventional PWM signal outputting circuit includes a counter 11; a channel 1 cyclic period setting register 12; a channel 1 duty setting register 13; a channel 2 cyclic period setting register 14; a channel 2 duty setting register 15; a first comparing unit 16a; a second comparing unit 16b; a third comparing unit 16c; a fourth comparing unit 16d; a channel 1 output control circuit 17; and a channel 2 output control circuit 18.
In the conventional PWM signal outputting circuit, the counter 11 is configured to operate synchronizing with a clock output from, for example, a timer and the like disposed in the micro-computer, so that the counter 11 counts the number of the clocks and outputs the number as a counter value.
In the conventional PWM signal outputting circuit, the channel 1 cyclic period setting register 12, the channel 1 duty setting register 13, the first comparing unit 16a, the second comparing unit 16b and the channel 1 output control circuit 17 constitute a first PWM signal generating unit for outputting a first PWM signal (PWM1). Similarly, the channel 2 cyclic period setting register 14, the channel 2 duty setting register 15, the third comparing unit 16c, the fourth comparing unit 16d and the channel 2 output control circuit 18 constitute a second PWM signal generating unit for outputting a second PWM signal (PWM2).
In the conventional PWM signal outputting circuit having the configurations described above, the first PWM signal generating unit and the second PWM signal generating unit are configured to generate and output the PWM signal with the duty value corresponding to the values set in the channel 1 cyclic period setting register 12, the channel 1 duty setting register 13, the channel 2 cyclic period setting register 14, and the channel 2 duty setting register 15, respectively, according to the counter value output from the counter 11.
In the conventional PWM signal outputting circuit, the first comparing unit 16a has a function as a reset circuit for resetting the counting operation of the counter 11 when the counter value output from the counter 11 reaches a specific value defined in advance.
In the conventional PWM signal outputting circuit, the first PWM signal generating unit and the second PWM signal generating unit are configured to store the values set in the channel 1 duty setting register 13 and the channel 2 duty setting register 15 as a start setting value, respectively. Further, the second comparing unit 16b and the fourth comparing unit 16d are configured to compare the counter value output from the counter 11 with the start setting values stored in the channel 1 duty setting register 13 and the channel 2 duty setting register 15, respectively. Further, the first PWM signal generating unit and the second PWM signal generating unit are configured to generate and output a start signal when the counter value matches to the start setting values.
Accordingly, when the second comparing unit 16b and the fourth comparing unit 16d output the start signals, the channel 1 output control circuit 17 and the channel 2 output control circuit 18 of the first PWM signal generating unit and the second PWM signal generating unit generate and output the first PWM signal (PWM1) and the second PWM signal (PWM2), respectively.
In the conventional PWM signal outputting circuit, the first PWM signal generating unit and the second PWM signal generating unit are configured to store the values set in the channel 1 cyclic period setting register 12 and the channel 2 cyclic period setting register 14 as a termination setting value, respectively. Further, the first comparing unit 16a and the third comparing unit 16c are configured to compare the counter value output from the counter 11 with the termination setting values stored in the channel 1 cyclic period setting register 12 and the channel 2 cyclic period setting register 14, respectively. Further, the first PWM signal generating unit and the second PWM signal generating unit are configured to generate and output a termination signal when the counter value matches to the termination setting values.
Accordingly, when the first comparing unit 16a and the third comparing unit 16c output the termination signals, the channel 1 output control circuit 17 and the channel 2 output control circuit 18 of the first PWM signal generating unit and the second PWM signal generating unit stop generating and outputting the first PWM signal (PWM1) and the second PWM signal (PWM2), respectively.
The operation of the first PWM signal generating unit and the second PWM signal generating unit will be explained next with reference to FIG. 2.
In the operation shown in FIG. 2, the termination setting value "7" is set in the channel 1 cyclic period setting register 12; the start setting value "2" is set in the channel 1 duty setting register 13; the termination setting value "4" is set in the channel 2 cyclic period setting register 14; and the start setting value "1" is set in the channel 2 duty setting register 15, respectively. With the setting values set as described above, the counter 11 operates synchronizing with the clock. When the counter value of the counter 11 matches to the start setting value "2" set in the channel 1 duty setting register 13, the second comparing unit 16b generates and outputs the start signal to the channel 1 output control circuit 17.
Accordingly, the PWM1 output from the channel 1 output control circuit 17 is changed from "L" (low) to "H" (high). Afterward, when the counter value of the counter 11 matches to the termination setting value "7" set in the channel 1 cyclic period setting register 12, the first comparing unit 16a generates and outputs the termination signal to the channel 1 output control circuit 17. Accordingly, the PWM1 output from the channel 1 output control circuit 17 is changed from "H" (high) to "L" (low). Further, the value of the counter 11 is cleared.
Further, when the counter value of the counter 11 matches to the start setting value "1" set in the channel 2 duty setting register 15, the fourth comparing unit 16d generates and outputs the start signal to the channel 2 output control circuit 18. Accordingly, the PWM2 output from the channel 2 output control circuit 18 is changed from "L" (low) to "H" (high). Afterward, when the counter value of the counter 11 matches to the termination setting value "4" set in the channel 2 cyclic period setting register 14, the third comparing unit 16c generates and outputs the termination signal to the channel 2 output control circuit 18. Accordingly, the PWM2 output from the channel 2 output control circuit 18 is changed from "H" (high) to "L" (low). Further, the PWM2 output is maintained at "H" (high) until the counter value of the counter 11 matches to the termination setting value "7" set in the channel 1 cyclic period setting register 12, that is, the value of the counter 11 is cleared.
Through the process described above, in the conventional PWM signal outputting circuit having the configuration shown in FIG. 1, it is possible to arbitrarily set the cyclic period and the duty with respect to the two channels.
As described above, in the first PWM signal generating unit and the second PWM signal generating unit, it is possible to arbitrarily set the start setting values and the termination setting values. As shown in FIG. 2, however, when the start setting values and the termination setting values are set, there is a period of time when both the first PWM signal PWM1 and the second PWM signal PWM2 output from the first PWM signal generating unit and the second PWM signal generating unit become "H".
In the conventional PWM signal outputting circuit, when both the first PWM signal PWM1 and the second PWM signal PWM2 become "H", and the first PWM signal generating unit and the second PWM signal generating unit are turned on (ON) during the period of time when both the first PWM signal PWM1 and the second PWM signal PWM2 become "H", there is a period of time when the two channels are simultaneously turned on. For example, when both the first PWM signal PWM1 and the second PWM signal PWM2 are used for controlling the IGBT and the like, a component of the IGBT may be damaged.
As described above, in the conventional PWM signal outputting circuit having the configuration shown in FIG. 1, it is possible to arbitrarily set the cyclic period and the duty with respect to the two channels. However, when the conventional PWM signal outputting circuit is used for controlling the IGBT and the like, the two channels are simultaneously turned on accidentally due to wrong setting.
In view of the problems described above, an object of the present invention is to provide a PWM signal outputting circuit and a method of controlling a PWM signal output capable of solving the problems of the conventional PWM signal outputting circuit. In the present invention, it is possible to set a plurality of PWM signals with a higher degree of flexibility. Further, it is possible to perform a proper operation even when each of the PWM signals is used in a mutually compensating manner.
Further objects and advantages of the present invention will be apparent from the following description of the present invention.

PWM (pulse width modulation) signal outputting circuit and method of controlling output of PMW signal


A multi-grained network includes edge modules that switch high-variance multi-rate data traffic, and independent core modules that switch paths having different granularities. The core may include core modules that switch fixed-size data blocks, core modules that switch channels or bands of channels, core modules that switch entire links, and core modules that cross-connect channels or links. To simplify the control functions, the core modules operate independently from each other. Direct link, band or channel connections may be established for selected ingress-egress edge module pairs, if traffic volumes warrant. The use of graded granularity in the core simplifies the control function and reduces network cost.

Data networks are generally constructed using a number of edge switches, also referred to as "edge modules", that are connected to local data sources and data sinks. The edge modules are interconnected by a network core that switches traffic between edge modules, as required. The network core may be a distributed core that includes a plurality of geographically distributed core modules. The network core may also be an agile core that is reconfigured to satisfy fluctuating traffic demands.
Links interconnecting the edge modules and the core modules support communications paths for transferring data between edge modules. Each of the communications paths has a predetermined granularity defined as an integer multiple of a capacity unit. A capacity unit is the minimum capacity, in bits per second, that may be assigned to a traffic stream. Traditionally, the granularity of links interconnecting edge modules with core modules is uniform. Several examples of architectures for modern data networks with links of uniform granularity are described in Applicant's copending United States patent applications referenced below.
In Applicant's copending U.S. patent application Ser. No. 09/286,431, filed on Apr. 6, 1999, and entitled SELF-CONFIGURING DISTRIBUTED SWITCH, a network architecture is described in which high-capacity electronic edge modules are interconnected by an agile channel-switching optical core. A global controller selects paths through the channel switched core and reconfigures the paths in response to dynamic changes in data traffic loads. Reconfiguration timing between the edge modules and the channel switch core modules is performed to keep reconfiguration guard time minimized.
In Applicant's copending U.S. patent application Ser. No. 09/475,139, filed on Dec. 30, 1999, and entitled AGILE OPTICAL-CORE DISTRIBUTED PACKET SWITCH, an architecture for an optical-core network in which a core module controller selects paths through an associated core module and reconfigures the paths in response to dynamic changes in data traffic loads is described. Switching latency in the core modules is masked so that the source edge modules need not disrupt data transmission during core reconfigurations. A slight surplus capacity is provided in the core modules to facilitate core reconfigurations. The reconfiguration functions of the edge modules and the core modules are coordinated to keep reconfiguration guard time minimized. This yields a high capacity, load-adaptive, self-configuring switch that can be widely distributed to serve a large geographical area.
In Applicant's copending U.S. patent application Ser. No. 09/550,489, filed Apr. 17, 2000, and entitled HIGH CAPACITY WDM-TDM PACKET SWITCH, a network architecture is described in which electronic edge modules are interconnected by space switches that are operated in a time division multiplexed (TDM) mode. The use of TDM permits a channel (typically a wavelength in a WDM transport medium) to be split into several sub-channels. This increases the number of edge modules that can be directly reached without a requirement for tandem switching. The network comprises a distributed channel switching core, the core modules being respectively connected by a plurality of channels to a plurality of high-capacity packet switch edge modules. Each core module operates independently to schedule paths between edge modules, and reconfigures the paths in response to dynamic changes in data traffic loads reported by the edge modules. Reconfiguration timing between the packet switch edge modules and the channel switch core modules is performed to keep reconfiguration guard time minimized.
In Applicant's copending U.S. patent application Ser. No. 09/624,079, filed Jul. 24, 2000, and entitled MULTI-DIMENSIONAL LATTICE NETWORK, a multi-dimensional lattice network that scales to capacities of the order of a Yotta b/s (1024 bits per second) includes a plurality of sub-nets of edge module switches interconnected by an agile switching core. A sub-net may be constructed as an agile optical-core network as described in patent applications referenced above, or as an agile electronic-based core, as described in U.S. patent application Ser. No. 09/550,489 referenced above.
Each of the above-described network architectures was designed around network links that support paths of a uniform granularity. It is well known that the elasticity and granularity of a path can have a considerable impact on a network's efficiency and control complexity. It is also well known that coarse paths (paths in which the capacity unit is very large, e.g., 10 Gb/s) reduce the number of control variables and thus simplify network control functions. However, if traffic volume does not warrant coarse path granularity, the use of coarse paths may dramatically reduce network efficiency. On the other hand, paths having a fine granularity (paths in which the capacity unit is relatively small, e.g., 100 Kb/s) tend to increase network efficiency since more direct paths can be established from each edge module to other edge modules in the network. This reduces the mean number of hops between edge modules. However, control complexity is increased, especially if the core modules are agile core modules, as described in Applicant's copending patent applications referenced above.
It is generally believed that the diversity of data traffic in modern data networks is increasing. Transfer rate requirements in networks with diverse traffic loads may vary from a few Kb/s to a few Gb/s, or even up to a Tb/s. In addition, data traffic patterns typically show that the bulk of data traffic originating from any edge switch is often directed to only a few other edge switches, the balance of the data traffic being widely distributed to a very large number of other edge switches. While existing networks can be configured to service such distributions of data traffic, they are not adapted to provide such service efficiently. Consequently, there is a need for a "multi-grained" network that is capable of economically handling extremes in transfer rate and distribution of traffic without unmanageable control complexity.


A CMOS transconductor for cancelling third-order intermodulation is provided. The transconductor includes a transconductance circuit and a tuneable distortion circuit. The transconductance circuit takes an input voltage and generates an output current having a transconductance element and an IM3 element. The distortion circuit takes the same input voltage and generates a current having an IM3 element of equal amplitude and opposite phase to the IM3 element of the transconductance circuit. A controller circuit tunes the distortion circuit to adjust its IM3 element to substantially equal the amplitude of the IM3 of the transconductance circuit. The distortion and transconductance circuits are arranged to sum their output currents thereby effectively cancelling the IM3 elements, leaving the transconductance relatively unmodified.

Wireless devices have been in use for many years for enabling mobile data and communication. Such devices can include mobile phones and wireless enabled personal digital assistants (PDAs) for example. FIG. 1 is a generic block diagram of the core components of such wireless devices. The wireless core 10 includes a baseband processor 12 for controlling application specific functions of the wireless device and for generating and receiving voice or data signals to a radio frequency (RF) transceiver chip 14. The RF transceiver chip 14 is responsible for frequency up-conversion of transmission signals, and frequency down-conversion of received signals. The RF transceiver chip 14 includes a receiver core 16 connected to an antenna 18 for receiving transmitted signals from a base station or another mobile device, and a transmitter core 20 for transmitting signals through the antenna 18 via a gain circuit 22. Those of skill in the art will understand that FIG. 1 is a simplified block diagram, and can include other functional blocks that may be necessary to enable proper operation or functionality.
Third-order intermodulation (IM3) is a common interference problem in RF where two or more signals mix in a non-linear phase or "device" to form one or more new signals, and thereby creating intermodulation products. In the RX section of a transceiver chip, these intermodulation signals may fall on top of a desirable signal (in frequency domain) thereby reducing the signal to noise ratio. For the TX section, intermodulation may cause the signal to spread out causing power to leak in a neighbouring band. Various elements within a radio use transconductance cells. These transconductance cells convert voltage into current, but also add third order harmonic distortion. As an example, active mixers typical use transconductance cells as an input stage to the mixing cell and are widely used in modern communication systems in order to achieve frequency translation of the carrier signals. Intermodulation distortion in the mixer affects the dynamic range of most communication systems. The IM3 of transconductance cells is governed by the voltage to current transfer function produced by elements within the cell (i.e. transistors) and the amount of feedback in the circuit
A typical output of a transconductance circuit is given by:iout=A1vin+A3vin3+ . . .where iout is the output current, A1 is the transconductance gain of the circuit, vin is the input voltage, and An are distortion terms where n>3. However, a nearly linear relationship between iout and vin is desirable since many communications standards specify the amount of distortion that is acceptable. Failure to comply with such standards may result in non-certification of a device. It is therefore desirable to eliminate distortions.
In the past, distortion cancellation was accomplished by techniques employing bipolar transistors as shown in such references as U.S. Pat. No. 6,781,467 (Sun), U.S. Pat. No. 5,497,123 (Main et al), S. Otaka, M. Ashida, M. Ishii, T. Lakura, "A+10 dBm IIP3 SiGe Mixer with Cancellation Technique," ISSCC2004, and B. Gilbert, "The MICROMIXER: A highly linear variant of the Gilbert mixer using a bisymmetric class-AB input stage" in J. Solid-State Circuits, vol. 32, pp. 1412-1423, September 1997. The general approach of linearization is to add circuitry such that the terms An are brought to zero and A1 remains approximately the same (in most cases A1 reduces); note, for an ideal amplifier An=0, where n is greater than or equal to 3. In Main et al and Otaka, A3 is made up of two terms that oppose each other; i.e.A3=A3+−A3−where A3+ and A3− are made equal using component values in the circuit. In Main et al a phase shifting technique is used and is applied to a mixer architecture. In Otaka, a resistor value is used set the A3 to zero. The linearization technique used by Gilbert consists of pre-distorting the signal so that the terms An are set to zero at the output after it passes thru a distorting amplifying stage, which will introduces excessive noise. Sun uses bipolar transistor technology for a low noise amplifier. All these methods reduce the amount of third order distortion, but these past implementations are bipolar based, opposed to Complementary Metal Oxide Semiconductor (CMOS) based. The advantages of CMOS technology are cost and the fact the technology improves at a rate given by Moore's Law. These techniques are also susceptible to manufacturing variations in device parameters. Specifically, the IM3 may not be reduced because of variations in transistors parameters from part to part. Other techniques use feedback to reduce the amount of IM3 in a circuit. However feedback circuits introduce noise and increase the total amount of current and area required by the circuit.
Such techniques also employ SiGe or GaAs devices and technology, which although they exhibit highly linear characteristics, the technologies are new and expensive. Consequently, the cost of manufacturing often outweighs the benefits of using such devices.
It is therefore desirable to provide CMOS technology for tuning out IM3 products in transconductance circuits. The invention described below is a tuneable method for reducing the IM3 tone in a transconductance element so to make it less susceptible to manufacturing variations and the transconductance implementation is described within CMOS technology.

Tuneable circuit for canceling third order modulation


A modified polyacetal is obtainable by heating 0.1 to 30 parts by weight of (B) a polymerizable compound having a modifying group such as an epoxy group, a carboxyl group or an acid anhydride group relative to 100 parts by weight of (A) a base polyacetal and introducing the modifying group of the polymerizable compound to the base polyacetal. The base polyacetal (A) includes (A1) a polyacetal selected from polyoxymethylene homopolymers and copolymers, and (A2) a polymerizable polyacetal having a functional group comprising a polymerizablly unsaturated bond. The introduction efficiency of the modifying group can be enhanced by adding 0.01 to 2.5 parts by weight of (C) a free-radical initiator relative to 100 parts by weight of the total amount of the components (A) and (B), and mixing the resultant mixture under a molten state of the polyacetal. According to such method, the affinity of the polyacetal is improved by introducing the modifying group to the base polyacetal with ease and high efficiency.

A polyacetal has excellent mechanical strength, slidability, heat resistance, chemical resistance, moldability (formability) and electrical characteristics, and hence is used as an engineering plastic in many fields. Further, a variety of performances have been practically required of such polyacetal accompanied with expanding applications.
On the other hand, the polyacetal has a high crystallinity and hence remarkably poor in affinity or compatibility for other materials. Therefore, it is difficult to modify or reform the polyacetal by means of blending and compounding with other polymers, additives or reinforcing agents and the like, and adhesive properties of the polyacetal with respect to a paint, a printing ink, a coloring agent or an adhesive can hardly be improved. By way of illustration, when an elastomer is blended with the polyacetal for improving impact resistance, satisfactory impact characteristics can not be imparted to the resultant molded article because of poor affinity and compatibility of the polyacetal for the elastomer. Further, the surface of the molded article is peeled off due to poor dispersibility of the elastomer, and hence the external appearance of the molded article is significantly sacrificed. Moreover, addition of a stabilizer, lubricant or other additive to the polyacetal for modification or reforming results in leaching of the additive to the surface of the molded article, and hence the appearance of the molded article is markedly deteriorated and functions of the additive can not be utilized effectively. Accordingly, application or use of the polyacetal may practically be limited to a great extent.
For the purpose of improving affinity of the polyacetal, it is useful to modify the polyacetal by introducing a modifying group into the polyacetal. As such modifying method of the polyacetal by introduction of a modifying group, there have been proposed a variety of technologies. By way of an example, Japanese Patent Publication No. 23467/1968 (JP-B-43-23467) proposes a process which comprises introducing an amino group into a base polyacetal with the use of aminoaldehyde as a comonomer. According to this process, however, boron trifluoride or other Lewis acid used as a polymerization catalyst is easily or readily reacted with the amino group, so that polymerization efficiency and hence characteristics as an engineering plastic are sacrificed.
Japanese Patent Publication No. 19425/1972 (JP-B-47-19425) proposes a process which comprises preparing a polymer with the use of a cyclic ether or cyclic acetal each having a nitro group as a comonomer, and reduction the resultant polymer to convert the nitro group into an amino group. However, in this process, the polymer is liable to be decomposed in the reducing step, and hence the characteristics of the obtained polymer are not satisfactorily high as an engineering plastic.
Japanese Patent Application Laid-open No. 21618/1991 (JP-A-3-21618) and Japanese Patent Application Laid-open No. 21619/1991 (JP-A-3-21619) propose production of a polyacetal copolymer having a hydroxyl group, an acyloxy group, for instance, with the use of a comonomer. Japanese Patent Application Laid-open No. 25238/1993 (JP-A-5-25238) offers a process which comprises copolymerizing trioxane and a cyclic ether or cyclic formal each having a nitrile group, a carboxyl group, an ester group or an amide group. According to these technologies, however, polymerization reactivity is poor so that a copolymer having a high molecular weight can hardly be obtained in a high yield. Japanese Patent Application Laid-open No. 93822/1991 (JP-A-3-93822) proposes a polyacetal copolymer having a nitrile group. However, this process requires an extremely large quantity of a polymerization catalyst and hence is not suitable for practical use.
As described above, in the processes in which copolymerization is conducted using a comonomer having a modifying group, the comonomer adversely affects on the polymerization reaction and, thereby, a smooth proceeding of the copolymerization is deteriorated and the polymerization degree can hardly be enhanced. In other words, the technologies, which comprise introducing a modifying group directly into a polyacetal with the use of a comonomer having a modifying group, each provide a decreased polymerization reactivity and a copolymer having a high molecular weight can hardly be provided in a high yield.
There has been also proposed incorporation of a polymerizable compound into a reinforced polyacetal resin composition for the purpose of improving reinforcing effect by means of a reinforcing agent. By way of an example, Japanese Patent Publication No. 6969/1985 (JP-B-60-6969) discloses a production method of a reinforced polyoxymethylene resin composition which comprises melting and kneading concurrently, in substance, a mixture prepared by adding, to 100 parts by weight of a polyoxymethylene resin, 5 to 150 parts by weight of an inorganic filler, and 0.1 to 20 parts by weight of an unsaturated polyester. This literature also describes that a radical polymerization initiator may preferably be molten and kneaded concurrently with the above mixture. Japanese Patent Publication No. 18383/1983 (JP-B-58-18383) discloses a production method of a carbon fiber-reinforced polyacetal resin composition which comprises kneading, in substantial concurrence, a mixture comprising 5 to 150 parts by weight of a carbon fiber, 0.1 to 20 parts by weight of an unsaturated polyester, 0 to 5 parts by weight of a radical polymerization initiator and 100 parts by weight of a polyacetal resin.
However, since the composition previously comprises the specific reinforcing agent, it is necessary to prepare the resin composition for each of applications. By way of an example, the carbon fiber-reinforced polyacetal resin composition shows gray through black color depending on the content of the carbon fiber so that it can not be applied to a chromatic colored molded article. Further, the molding conditions must be strictly controlled since the unsaturated polyester is apt to be cross-linked in the melting and kneading step, and appearance and quality of the molded article are deteriorated due to a granule, typically speaking, formed by crosslinking of the unsaturated polyester.
Japanese Patent Publication No. 18384/1983 (JP-B-58-18384) discloses a carbon fiber-reinforced polyacetal resin composition as produced by heating and kneading, concurrently in substance, 100 parts by weight of a polyacetal resin, 5 to 150 parts by weight of a carbon fiber, 0.01 to 5 parts by weight of a radical polymerization initiator and 0.1 to 20 parts by weight of acrylamide, N-methylolacrylamide or divinylbenzene. When the crosslinkable divinylbenzene is used in this process, disadvantages similar to the composition as produced using the unsaturated polyester would be present.
Furthermore, Japanese Patent Publication No. 36644/1984 (JP-B-59-36644) discloses a reinforced polyoxymethylene resin composition comprising a heated and kneaded product containing 100 parts by weight of polyoxymethylene, 5 to 150 parts by weight of a non-carbonaceous inorganic filler, 0.01 to 5 parts by weight of a radical polymerization initiator and 0.1 to 20 parts by weight of acrylamide or N-methylolacrylamide. Japanese Patent Application Laid-open No. 219252/1985 (JP-A-60-219252) discloses a glass fiber-reinforced polyacetal resin composition as produced by adding a glass fiber, a peroxide and a silane-based coupling agent to a polyacetal resin.
Since the unmodified polyacetal is poor in wettability with respect to a reinforcing agent or filler, the above mentioned composition can hardly provide a homogeneous dispersion of the reinforcing agent or filler with a high efficiency even when kneaded. Further, coexistence of the reinforcing agent or filler significantly sacrifices modification efficiency. Therefore, even when the composition is molded, functions or properties of the reinforcing agent or filler can not effectively be exhibited and the molded article may occasionally be imparted with excellent mechanical characteristics, electrical characteristics or other characteristics.
In particular, these technologies, in which the filler or radical polymerization initiator is employed, can hardly be referred to as effective modifying processes, since introduction efficiency of the modifying group is extremely poor and the polyacetal is decomposed or degraded.
Moreover, when the radical polymerization initiator and the polyacetal are molten and kneaded, the polyacetal resin is decomposed and degraded, due to the radical polymerization initiator, to give a decreased molecular weight. For instance, the above-mentioned Japanese Patent Application Laid-open No. 219252/1985 (JP-A-60-219252) discloses that melting and kneading of the peroxide and the polyacetal results in oxidative decomposition of the polyacetal resin due to the radical polymerization initiator. Further, Japanese Patent Application Laid-open No. 74790/1974 (JP-A-49-74790) discloses a process for controlling an average molecular weight of a polyacetal resin which comprises decomposing a polyoxymethylene by contacting the same with an organic peroxide in a molten state of the polyoxymethylene, and British Patent No. 1172741 discloses a process for reducing an average molecular weight which comprises treating a polyacetal with a peroxide in the presence of a dispersing agent or a solvent. As described above, the use of a radical polymerization initiator, in particular an organic peroxide, results in decomposition of the polyacetal, so that it is difficult to modify or reform the polyacetal by means of the radical polymerization initiator with retaining its high molecular weight, mechanical characteristics and electrical characteristics. Probably for this reason, Japanese Patent Application Laid-open No. 214212/1993 (JP-A-5-214212) proposes reforming (modification) of a polyoxymethylene resin by adding a modified polyolefin modified with a polymerizable monomer having a glycidyl group and an amide bond, without direct modification of the polyacetal.
Still more, N-methylolacrylamide may easily be self-condensed to form a dimer and be liable to be crosslinked, so that moldability or formability of the composition is deteriorated or appearance and quality of the molded article are sacrificed due to crosslinking. Further, since acrylamide is reacted with formaldehyde formed in kneading with the polyacetal to give the above N-methylolacrylamide, similar problems to the above would arise.
It is, therefore, an object of the present invention to provide a modified polyacetal which is imparted with high affinities for a polymer, reinforcing agent and/or filler and a method of producing the same.
It is another object of the invention to provide a modified polyacetal having a high molecular weight despite being introduced with a modifying group, and a method of producing such modified polyacetal.
A further object of the present invention is to provide a modified polyacetal with inhibiting a molding processabilities and recycling properties (reutility), and its production method.
It is a yet another object of the invention to provide a modified polyacetal which is introduced with a comparatively large quantity of a modifying group with a high efficiency into a base polyacetal, and a method of producing the modified polyacetal.
A still further object of the invention is to provide a production method of a modified polyacetal which insures inhibition of deterioration of its performance due to decomposition and/or degradation without interfering with formation reaction of a polyacetal, and provides an efficient modification (reforming) of the polyacetal with retaining inherently excellent performances of such polyacetal.
It is a further object of the present invention to provide a method of producing a modified polyacetal which insures, despite using a radical initiator, modification of a polyacetal with a high efficiency by the compound having a modifying group, to inhibit decrease of its molecular weight.
A yet further object of the invention is to provide a production method of a modified polyacetal which is able to provide a polymer having a molecular weight within a comparatively broad range.
It is a still another object of the invention to provide a method of producing a modified polyacetal which insures direct introduction of a modifying group into a polyacetal with a high efficiency in a simple and easy manner without the coexistence of a reinforcing agent or filler.

Modified polyacetal and method of producing the same


A system and a method for controlling temperature in different zones of a premises. A method includes receiving a measurement of temperature sensed by a first fire detector positioned at a first zone of a premises. The method further includes receiving a measurement of temperature sensed by a second fire detector positioned at a second zone of the premises. The method also includes controlling the temperature by a thermostat in the first zone based on the measurement of the sensed temperature received from the first fire detector and in the second zone based on the measurement of the sensed temperature received from the second fire detector.

Different zones/rooms/areas of a premises have individual temperature sensors to sense temperature in each zone. The temperature sensors positioned in each of the zones can transmit readings of the sensed temperature to a thermostat. Based on the readings received from the sensors, the thermostat controls the temperature in each zone. Further, thermostats having in-built temperature sensors may also be installed in each zone for sensing temperature. Based on the sensed temperature, the thermostats may control temperature in each zone. Therefore, a separate thermostat or a separate temperature sensor is required to be installed in each zone for sensing and controlling temperature in each zone. Such an existing solution for sensing temperature in each zone is a costly solution as a separate thermostat or a separate temperature sensor needs to be purchased and installed.
In view of the afore-mentioned problems, there is a need of an efficient and effective system and a method for sensing and controlling temperature in different zones of a premises. There is also a need to provide cost-effective solution for eliminating the need of using a separate thermostat or a separate temperature sensor for sensing temperature in each zone. In order to solve the problems in the existing solutions, a system and a method are disclosed.

Method and a system for controlling temperature in different zones of a premises