A dispersion compensator is formed by an angular dispersion element, a diffracting optical element, and a reflecting mirror. By forming a reflecting surface in free-formed surfaces which are different between Y-Z plane and X-Z plane and shifting a reflecting position on a reflecting surface per wavelengths, dispersion and dispersion slope are compensated by having an optical path length difference per wavelengths. By doing this, it is possible to realize a dispersion compensator which can compensate dispersion and dispersion slope simultaneously with low loss.

The present application is based on patent application No. 2002002-194760 filed in Japan, the content of which is incorporated herein by reference.
1. Field of the Invention
The present invention relates to a dispersion compensator for compensating for a deterioration in an optical signal which is caused by a dispersion of a light which is transmitted in an optical transfer element such as an optical fiber which is used for an optical communication. The present invention particularly relates to a dispersion compensator which can compensate a chromatic dispersion and a dispersion slope which are caused in the optical transfer element.
2. Description of Related Art
There has been an increasing requirement for larger capacity in an optical communication system as a traffic in a communication increases according to an Internet which is rapidly used commonly. Conventionally, larger communication capacity has been realized by increasing a transmission speed based on a faster processing speed in an electronic circuit. However, a recent request for increasing the communication traffic exceeds what can be realized by making use of faster processing speed in such an electronic circuit. Presently, it is inevitable to use a wavelength division multiplexing (hereinafter called WDM) method together with the higher speed processing operation by an electronic circuit.
Presently, an optical transmission speed which is commercially realized has a limit such as 10 Gb/s. According to the latest status in this area in the art, a transmission speed such as 40 Gb/s has already been realized under non-commercial condition such as under a Research and Development condition because of an improved electronic device using a composite-semiconductor. Regarding a medium which us used for an optical communication, there is a serious problem wider width in a transmission pulse width caused by a dispersion in that a transmission speed of a light which exists in a transmission medium alters based on a wavelength or a polarization condition of a light in case of a high transmission over 10 Gb/s. It is understood that it is necessary to reduce a decrease an entire system for transmitting a light to zero.
For Methods for decreasing such a dispersion, following methods can be commonly used for example. In a method, dispersion in an optical fiber is reduced by using a dispersion shift fiber which adjust a zero-dispersion wavelength in a fiber to a transmission wavelength. In other method, a dispersion compensation fibers (hereinafter called DCFs) which have an opposite characteristics to an optical fiber such as a single mode fiber (hereinafter called SMF) are disposed in constant intervals have been used commonly.
On the other hand, more strict control for dispersion is required under condition of transmission speed such as 40 Gb/s; thus, it is necessary to correct the dispersion in an optical fiber which is caused by a temperature condition dynamically.
In order to solve such problems, a fiber brag-grating (hereinafter called an FBG) and a virtually-imaged-phased-array (hereinafter called a VIPA) have been proposed. For a dispersion compensator using a VIPA, a dispersion compensator can be named which is disclosed in a patent document such as Published Japanese Translation No. 2000-511655 of PCT. In this dispersion compensator, a light which is ejected from an optical fiber is collimated. After that, the collimated light is condensed and transmitted through a VIPA which is disposed in a focal point of the transmitted light. Thus, a light flux which can be identified according to each wavelength therein is generated so as to be a parallel light. The parallel light is condensed and reflected by a reflection mirror which is disposed in a focal point. The reflected light returns to an optical fiber by reversing the reflected light in the same optical system thereabove.
According to such a dispersion compensator, a light which is outputted from the VIPA is condensed in a different point on the reflecting mirror, and a surface on on the reflection is formed in a certain shape. By doing this, it is possible to generate an optical path length difference. Thus, a chromatic dispersion is compensated because different wavelengths transmit for different distances.
For a member to compensating the dispersion slope, a dispersion compensator which is disclosed in a patent document such as U.S. Pat. No. 6,301,048 is proposed. According to the document, a method is disclosed by which a dispersion and a dispersion slope are compensated concurrently by using a VIPA and a diffracting grating.
An object of the present invention is to provide a dispersion compensator which can compensate a chromatic dispersion and a dispersion slope under condition that an insertion loss can be restricted in a minimum level.
Another object of the present invention is to provide a dispersion compensator and a dispersion compensating system which do not need a large space for realizing functions for varying a dispersion to be compensated and a dispersion slope.
A dispersion compensator according to the present invention is characterized in comprising an angular dispersion element for changing an angle of a light which is ejected from an optical transfer element according to a wavelength in the ejected light, a diffracting optical element having at least a concave reflecting surface so as to diffract the ejected light, and a reflecting mirror having a reflecting surface which is disposed near a focal point in an entire optical system of which surface shape of the reflecting mirror changes in a dispersing direction of the ejected light according the wavelength in the ejected light.
Also, a dispersion compensator according to the present invention is characterized in comprising an angular dispersion element for changing an angle of a light which is ejected from an optical transfer element according to a wavelength in the ejected light, an optical element having a light-condensing function, a diffracting optical element having at least a concave reflecting surface so as to diffract the ejected light, and a reflecting mirror having a reflecting surface which is disposed near a focal point in an entire optical system of which surface shape of the reflecting mirror changes in a dispersing direction of the ejected light according the wavelength in the ejected light.
Also, it may be acceptable that the focal point in which an image is focused by the optical element and the reflecting surface of the reflecting mirror are disposed on a circumference which is formed according to a radius of curvature in the concave reflecting surface in the diffracting optical element.
Also, according to the present invention, a dispersion compensator is characterized in comprising an angular dispersion element for changing an angle of a light which is ejected from an optical transfer element according to a wavelength in the ejected light, an optical element having a light-condensing function, an optical deflecting device for deflecting a light which is ejected from the optical element near a focal point in which the light which is ejected from the optical element is focused, a diffracting optical element having at least a concave reflecting surface so as to diffract the ejected light, and a reflecting mirror having a reflecting surface which is disposed near a focal point in an entire optical system of which surface shape of the reflecting mirror changes in a dispersing direction of the ejected light according the wavelength in the ejected light.
Also, according to the present invention, it may be acceptable that the reflecting surface on the optical deflecting device and the reflecting surface on the reflecting mirror are disposed on a circumference which is formed according to a radius of curvature in the concave reflecting surface in the diffracting optical element.
Also, it may be acceptable that the diffracting optical element is a concave-surfaced diffracting grating, and a grating pitch in the concave-surfaced diffracting grating differs according to an area on a concave-surfaced reflecting surface. Also, it may be acceptable that the grating pitch in the concave-surfaced diffracting grating differs according to an area in a direction orthogonal to a direction of chromatic dispersion by the angular dispersion element which is disposed on the concave reflecting surface.
Also, it may be acceptable that the diffracting grating is provided with a blaze angle.
Also, it may be acceptable that the focal point in which an image is focused by the optical element and the reflecting surface of the reflecting mirror are movable such that the focal point in which an image is focused by the optical element and the reflecting surface of the reflecting mirror maintain such a relationship to be disposed on a circumference which is formed according to a radius of curvature in the concave reflecting surface in the diffracting optical element.
Also, it may be acceptable that the diffracting optical element can be rotated around a fulcrum which is disposed in a center of a curvature in the reflecting surface of the diffracting optical element.
Also, it may be acceptable that the reflecting surface on the reflecting mirror has a power at least in a surface orthogonal to a direction of chromatic dispersion by the angular dispersion element.
Also, it may be acceptable that the reflecting surface on the reflecting mirror has a power at least in a plane which includes a direction of chromatic dispersion by the angular dispersion element.
Also, it may be acceptable that the reflecting surface on the reflecting mirror is formed in rotatively an asymmetrical free-form surface.
Also, it may be acceptable that the reflecting surface on the reflecting mirror is provided with a surface which is disposed diagonally in an incident optical axis at least in a plane which includes a direction of chromatic dispersion by the angular dispersion element.
Also, it may be acceptable that the reflecting surface on the reflecting mirror is movable in a direction approximately orthogonal to an incident optical axis.
Also, it may be acceptable that the reflecting surface on the reflecting mirror is movable at least in a surface orthogonal to a direction of chromatic dispersion by the angular dispersion element.
Also, it may be acceptable that the reflecting surface on the reflecting mirror is movable in a plane which includes a direction of chromatic dispersion by the angular dispersion element.
Also, it may be acceptable that an optical surface or an optical member which has a positive power is disposed in a plane which includes at least a surface in a direction in which a wavelength is dispersed by the angular dispersion element in an optical path between the angular dispersion element and the reflecting surface on the reflecting mirror.
Also, it may be acceptable that the optical surface which has a positive power in a plane which includes a direction of chromatic dispersion by the angular dispersion element is a reflecting surface made by the concave-surfaced diffracting grating.
Also, it may be acceptable that the reflecting surface made by the concave-surfaced diffracting grating is an anamorphotic surface.
Also, it may be acceptable that the reflecting surface made by the concave-surfaced diffracting grating is rotatively an asymmetrical free-form surface.
Also, it may be acceptable that the optical member which has a positive power in a plane which includes a direction of chromatic dispersion by the angular dispersion element is a cylindrical lens which is disposed between the angular dispersion element and the reflecting mirror.
Otherwise, it may be acceptable that the optical member which has a positive power in a plane which includes a direction of chromatic dispersion by the angular dispersion element is an anamorphotic lens or a free-form-surfaced lens which is disposed between the angular dispersion element and the reflecting mirror.
Also, it may be acceptable that the optical element is an optical deflecting device which is provided with a reflecting surface which has a positive power. In the present invention, it may be acceptable that the optical deflecting device is a reflecting diffracting grating.
Also, it may be acceptable that the optical element is a concave-surfaced mirror having a positive power which is disposed between the angular dispersion element and the diffracting optical element.
Also, according to the present invention, it may be acceptable that the concave-surfaced mirror is an anamorphotic concave-surfaced mirror.
Also, it may be acceptable that the optical element is provided with a free-form reflecting surface which is disposed between the angular dispersion element and the diffracting optical element.
In the present invention, an interferometer, a Fabry-Pxc3xa9rot-interferometer, an etalon, a VIPA, a diffracting grating, or a prism can be used for an angular dispersing element.
Also, in the present invention, it may be acceptable that the diffracting grating is provided with a surface having a blaze angle.
According to the present invention, a dispersion compensating system is characterized in comprising a dispersion compensator of the above aspect of the present invention, a signal monitor which monitors a light which is ejected from the dispersion compensator and outputs a signal which contains at least an information for a dispersion of the light or an information for a dispersion slope, and a control device which controls a movement of the reflecting mirror such that at least a dispersion or a dispersion slope is reduced according to the signal which is outputted from the signal monitor.
Also, in a dispersion compensating system, it may be acceptable that a deflecting angle by an optical deflecting device is controlled instead of using a reflecting mirror so as to adjust at least one of the chromatic dispersion or the dispersion slope automatically. Otherwise, it may be acceptable that a position of the diffracting optical element is controlled.

Dispersion compensator and dispersion compensating system


The invention, belongs to the field of wastewater treatment technology, is a two-phase anaerobic reactor enhanced by addition of zero valent iron (ZVI). In the reactor, 2˜4 ZVI-filling layers are settled in the middle of the anaerobic hydrolysis-acidification tank, the effluent of which is fed into the rear anaerobic methanogenic tank. The degradation of organics is effectively enhanced in the anaerobic hydrolysis-acidification tank with dosing of ZVI, which may produce more acetic acid that is a desired substrate for the subsequent methanogenesis. Meanwhile, the acidic environment of the hydrolysis-acidification tank is helpful for the dissolution of ZVI to maintain its activity. The reactor is reasonably designed with high performance and strong shock resistance in anaerobic treatment of various wastewaters. Tests in lab-scale showed that hydrolysis-acidification and methanogenesis in this combined system were significantly improved compared with a reference reactor without addition of ZVI.

Most of chemical, pharmaceutical and coking industries discharge high-strength organic wastewaters with low biodegradability. These effluents are difficult to treat because of containing toxic substances and its high chemical stability. It poses a great risk to the environment and human health once these effluents enter into water body.
Anaerobic wastewater treatment process has obvious advantages in treatment of high-strength organic wastewater due to its high volume load, low energy consumption and even generating energy gas (i.e., CH4). The volume load of anaerobic process can reach several to dozens kilograms of COD/m3 d, which is generally more than ten times of aerobic process. Therefore, anaerobic technology is considered as a suitable method to treat high concentration of organic wastewater.
However, anaerobic process is susceptible to the operational conditions, such as pH, oxidation-reduction potential (ORP) and temperature. Especially, maintaining a neutral pH value is crucial for anaerobic methanogenesis, but pH balance between acidification and methanogenesis is easily destroyed because acidification generates acidity fast while methanogenesis consumes acidity slowly. As a result, the anaerobic performance will decrease when the anaerobic reactor presents acidity.
In order to improve the stability of anaerobic wastewater treatment, it is necessary to create a favorable pH condition for methanogenesis. So far, adding alkaline in the inlet or the anaerobic reactor is frequently used to control acidic pH. However it not only increases the complexity of the operation, but also makes the alkaline concentration in the dosing point much higher than other parts, which may cause serious damage (alkalinity, salinity, anion, etc.) to the anaerobic system.
As a cheap and environmentally friendly reductant, zero-valent iron (ZVI) has received much attention in the field of pollution control in recent years. It was reported that in the anoxic groundwater, ZVI could not only directly decompose organic chlorine as electron donor, but also promote the metabolism of methane-producing bacteria and then speed up the mineralization of organic chlorine. Permeability activity grille (PRB), based on this principle, has been applied in the groundwater treatment and soil remediation. In wastewater treatment, ZVI is mainly used in the preprocessing to improve the biodegradability prior to biotreatment. In our patent application CN200910012293.4, ZVI is put in a single anaerobic reactor, in which releasing ferrous ion compressed the electric double layer to reduce the Zeta potential. As a result, the methanogenesis was enhanced and the anaerobic sludge granulation was accelerated. In addition, ZVI could reduce the ORP in the anaerobic reactor to create a more reductive environment for the growth of methanogenesis.

Zero-valent iron two-phase anaerobic reactor


A measurement pickup, or transducer, includes at least one measuring tube for the conveying of a fluid. The measuring tube has an inlet end and an outlet end and vibrates at least at times. For enabling the fluid to be measured to flow through the measuring tube, the measuring tube communicates, via a first tube segment opening into the inlet end and via a second tube segment opening into the outlet end, with a pipeline connected therewith. For the oscillatable holding of the measuring tube, the measurement pickup further includes a support element having a first end piece containing a passageway for the securement of the first tube segment and having a second end piece containing a passageway for the securement of the second tube segment. Each of the two tube segments extends through its respective one of the two passageways and each of the two passageways has an inner diameter, which is greater than an outer diameter of its associated tube segment, so that an intermediate space is formed between each of the associated tube segments and end pieces. The measurement pickup further includes at least one, preferably metal, first spring element pushed onto one of the two tube segments. The spring element fills the intermediate space formed between tube segment and end piece at least partially, with the spring element being arranged in the intermediate space in such a manner that it contacts, at least sectionally, both its associated tube segment and also its associated end piece in such a manner that it is subjected, at least sectionally, to radially acting, deformation forces. As a result of elastic deformations accompanying such deformation forces, the spring element is held pressed against the associated tube segment and the associated end piece, whereby such tube segment is locked securely in the associated passageway.

For the measuring, or registering, of a process variable of a media flowing in pipelines, especially for the registering of flow-dynamic and/or rheological, measured variables of fluids, inline measuring devices working according to the most varied of physical principles are used in measurements and automation technology. For registering the particular process variable, for example a mass flow, a density and/or a viscosity of a fluid, the inline measuring device has a corresponding, most often physical-to-electrical, measurement pickup, or transducer, which is inserted into the course of the line conveying the medium and which serves for producing at least one measurement signal, especially an electrical measurement signal, representing, as accurately as possible, the primarily registered, process variable. The measurement pickup is, in such case, connected with the pipeline e.g. by means of flanges, tightly against leakage of the medium, especially pressure-tightly, and, mostly, also lastingly.
For operating the measurement pickup, especially also for the further processing or evaluating of the at least one measurement signal, such is additionally attached to a corresponding measuring device electronics. In the case of inline measuring devices of the described type, the measuring device electronics is, in turn, usually connected via an attached data transmission system, with other inline measuring devices and/or with appropriate process control computers, to which they transmit the measured signals e.g. via (4 mA to 20 mA)-current loops and/or digital data bus. Serving often, in such case, for data transmission systems are, especially serial, fieldbus systems, such as e.g. PROFIBUS-PA, FOUNDATION FIELDBUS, together with the corresponding transmission protocols.
By means of the process control computer, the transmitted, measured-value signals can be processed further and visualized e.g. on monitors as corresponding measurement results and/or they can be converted into control signals for process-influencing actuators, such as e.g. solenoidal valves, electric motors, etc. For the accommodating of the measuring device electronics, such inline measuring devices include further an electronics housing, which, as proposed e.g. in WO-A 00/36 379, can be arranged remotely from the measurement pickup and connected with such only over a flexible line, or which, as shown e.g. also in EP-A 1 296 128 or WO-A 02/099363, is arranged directly on the measurement pickup, especially in the form of a measurement pickup housing, which houses the measurement pickup.
For the measuring of, especially, mass flows, e.g. flow rates, densities and/or viscosities of flowing media, inline measuring devices having a vibration-type measurement pickup for insertion into the course of a pipeline conveying the fluid to be measured have become established over a considerable period of time. Such inline measuring devices, or measurement pickups, their mechanical construction or also measuring and evaluation processes producing corresponding measurement signals are described e.g. in EP-A 189 230, EP-A 527 176, EP-A 1 154 243, EP-A 1 158 289, EP-A 1 223 412, EP-A 1 296 128, U.S. Pat. Nos. 4,524,610, 4,768,384, 4,801,897, 4,823,614, 5,231,884, 5,359,881, 5,602,345, 5,661,232, 5,687,100, 6,006,609, 6,327,915, 6,343,517, 6,354,154, 6,487,917, 6,513,393, 6,634,241, US-A 2003/0154804, US-A 2003/0097881, US-A 2003/0097884, WO-A 88 02 476, WO-A 95/16 897, WO-A 01/02813, WO-A 01/02816, WO-A 02/099363, WO-A 03/048693. Especially, in U.S. Pat. Nos. 6,634,241, 6,487,917, 6,354,154, 6,343,517, 6,327,915, vibration-type measurement pickups, especially Coriolis mass flow pickups, are shown, which, in each case, include:                at least one measuring tube for the conveying of a fluid, which measuring tube has an inlet end and an outlet end and vibrates at least at times,        wherein the measuring tube, for enabling the fluid to flow through the measuring tube, communicates, via a first tube segment opening into the inlet end and via a second tube segment opening into the outlet end, with a pipeline connected therewith, and        wherein the measuring tube executes, during operation, mechanical oscillations about an imaginary oscillation axis connecting the two tube segments; and        a support element for the oscillatable holding of the measuring tube,        having a first end piece containing a passageway for the securement of the first tube segment and        having a second end piece containing a passageway for the securement of the second tube segment;        wherein each of the two tube segments extends through its respective one of the passageways and each of the two passageways has an inner diameter, which is greater than an outer diameter of its associated tube segment, so that an intermediate space is formed between each of the associated tube segments and end pieces.
Additionally, measurement pickups of the described type include an exciter mechanism electrically connected with a corresponding measuring device electronics and serving for the driving of the at least one measuring tube. The exciter mechanism includes an oscillation exciter, especially an electrodynamic, or electromechanical, oscillation exciter, mechanically acting on the measuring tube. Such measurement pickups also include a sensor arrangement for delivering oscillation measurement signals. The sensor arrangement includes at least two sensor elements spaced from one another for reacting to vibrations of the measuring tube. During operation, the exciter mechanism is so actuated in suitable manner by the measuring device electronics by means of corresponding exciter signals, that the measuring tube executes, at least temporarily, vibrations, especially bending oscillations. For the sake of completeness, it is noted here that the illustrated support elements are usually completed to form a measurement pickup housing, which houses the at least one measuring tube, together with the oscillation exciters and sensors arranged thereon, as well as possible other components of the measurement pickup.
In principle, such measurement pickups, or transducers, come with two types of tube geometries, namely, on the one hand, straight measuring tubes and, on the other hand, bent measuring tubes, among which the U-shaped, or U-like, tubes are preferred tube shapes. Especially in the case of Coriolis pickups measuring mass flow, for reasons of symmetry, both types of tube geometries are most often used in the form of two measuring tubes extending in two parallel planes parallel to one another and, most often, also both containing fluid flowing through, naturally, also in parallel. For the one of the two variants having two parallel, straight tubes, reference can be made to, for example, U.S. Pat. Nos. 4,768,384, 4,793,191 and 5,610,342, and, for the other variant having two parallel, especially identically formed, U-shaped tubes, reference can be made e.g. to U.S. Pat. No. 4,127,028. Besides these types of mass flow pickups of double measuring tube arrangement working on the Coriolis principle, another type of measurement pickup has long been established in the market, namely those with a single straight or bent measuring tube. Measurement pickups of this type are described e.g. in U.S. Pat. Nos. 4,524,610, 4,823,614, 5,253,533, 6,006,609 or WO-A 02/099363.
For the case in which the measurement pickup being used involves one with a single, straight, measuring tube, the measurement pickup further includes a counter-oscillator affixed to the measuring tube and suspended, especially oscillatably, in the measurement pickup housing. The counter-oscillator serves, apart from holding the oscillation exciter and the sensor elements, for oscillatory decoupling of the vibrating measuring tube from the connected pipeline. This compensation cylinder can, in such case, be embodied e.g. as a tubular compensation cylinder, or box-shaped support frame, arranged coaxially with the measuring tube. To the referenced ensemble of features of the individual, above-described measurement pickups can also be added that a straight measuring tube, or the straight measuring tubes, as the case may be, is/are preferably made of pure titanium, a titanium alloy of high titanium content, pure zirconium or a zirconium alloy of high zirconium content, since, compared to measuring tubes of stainless steel, which is, per se, possible for straight measuring tubes, shorter installed lengths result, while a bent measuring tube, or bent measuring tubes, as the case may be, is/are preferably made of stainless steel, although titanium or zirconium, or their alloys, are also possible, in such case, as material of the measuring tubes.
In the case of inline measuring devices of the described kind, which are applied as Coriolis mass flow meters, their measuring device electronics determine, in operation, among other things, a phase difference between the two oscillation measurement signals delivered from the sensor elements and issue at their outputs a measurement signal derived therefrom, which presents a measured value corresponding with the behavior, over time, of the mass flow rate. If, as is usual for such inline measuring devices, also the density of the medium is to be measured, then the measuring device electronics determines additionally on the basis of the oscillation measurement signals an instantaneous oscillation frequency of the measuring tube. Moreover, also, for example, the viscosity of the medium can be measured on the basis of the power, especially a corresponding exciter current, for the exciter mechanism needed to maintain the oscillations of the measuring tube.
Besides the possibility of simultaneous measurement of a plurality of such process variables, especially mass flow, density and/or viscosity, by means of one and the same measuring device, there is another, significant advantage of inline measuring pickups of vibration-type, that they exhibit, among other things, a very high accuracy of measurement coupled with relatively little susceptibility to disturbances. Beyond this, such measuring devices can be used for practically any flowable medium and practically in any area of application in measurement and automation technologies.
In the manufacture of such measurement pickups of vibration-type, as already discussed in detail in U.S. Pat. Nos. 5,610,342, 6,047,457, 6,168,069, 6,598,281, 6,634,241 or also WO-A, the securement of the measuring tube within the support element, be it by welding, brazing, soldering and/or pressing, can be a special problem, especially with regard to the stability of the zero point and/or the availability of the measurement pickup. Additionally, as perceivable from U.S. Pat. Nos. 6,047,457, 6,168,069, 6,598,281, 6,634,241 or 6,523,421, considerable problems can also arise in the securement of the measuring tube inside of the support element, when measuring tube and support element are of different materials, for example titanium and high-grade steel, especially high-grade stainless steel.
As, furthermore, explained in, among others, also in U.S. Pat. Nos. 5,610,342, 6,047,457 or WO-A 03/048693, a suitable solution of the problem can be realized by affixing the measuring tube terminally in the support element by force- and/or interlocking-fit, with this force and/or interlocking fit being brought about by means of cold forming of the end pieces and/or of the tube segments. Studies of measurement pickups manufactured in this way have, however, shown, that the usually different expansion characteristics of the above-mentioned end pieces and the tube segments of the measuring tube held therein can lead to the fact that the clamping forces exerted by the end pieces on the measuring tube fall, in the case of temperature fluctuations, especially in the case of possible temperature shocks, such as can arise e.g. in the case of regularly performed cleaning operations with extremely hot washing liquids, below a critical value. This can, in turn, mean that the end piece and measuring tube lose, because of thermally-related expansions, the mechanical contact brought about by the rolling and, consequently, the support element becomes rotatable about the above-mentioned oscillation axis, relative to the measuring tube. After that, especially in the case of measurement pickups executing, during operation, also torsional oscillations about the oscillation axis, with a slipping of the support being an event that is no longer, with certainty, out of the question, a replacement of the entire measuring device becomes practically unavoidable. Comparable effects have been discussed in this connection also in WO-A 03/048693 and U.S. Pat. No. 6,598,281.

Vibration-type measurement pickup and its measuring tube


A method of lighting a high-pressure discharge lamp is configured to change a power to be supplied to the high-pressure discharge lamp in accordance with a luminance parameter of an image content. The method includes switching between a low temperature operation and a high temperature operation so as to maintain a condition that mercury encapsulated into an arc tube part of the high-pressure discharge lamp constantly partially deposits without evaporating. The low temperature operation is performed where the temperature in the arc tube part is less than or equal to the deposition temperature of the mercury, whereas the high temperature operation is performed where the temperature in the arc tube part is greater than the deposition temperature of the mercury.

1. Field of the Invention
The present invention relates to a lighting method of a high-pressure discharge lamp and a lighting circuit for the same, whereby occurrence of deficit and distortion of a projected image can be avoided in applying the high-pressure discharge lamp to a projector or so forth.
2. Background Art
A high-pressure discharge lamp has been widely used for a projector and so forth, and is characterized in that quite a large amount of light is obtainable from a single high-pressure discharge lamp. In the high-pressure discharge lamp, a pair of electrodes is disposed in the internal space of an arc tube part made of silica glass, and mercury is encapsulated into the internal space. When voltage is applied to the electrodes, an arc discharge is generated. Accordingly, evaporated mercury is excited and emits light.

Method and circuit for lighting high-pressure discharge lamp


A method for treating a cellulose-containing substrate is provided in the present invention, the method comprising contacting a silicone composition comprising at least one polysiloxane or silicone resin containing at least one functional group comprising at least one dialkylacetal group, at least one anhydride group, at least one reactive group, or combinations thereof with the cellulose-containing substrate; and curing the silicone composition on the cellulose-containing substrate at a temperature in a range between about 25xc2x0 C. and about 200xc2x0 C. A further embodiment of the present invention includes a formulation containing the aforementioned silicone composition.

The present invention relates to compositions for textile applications. More particularly, the present invention relates to silicone compositions which adhere durably to textiles.
Silicones are used in the textile industry due in part to the unique benefits that they impart to the materials, such as softness. One problem in the industry is lack of durability in fabric treatments. In many applications, the silicone is deposited on textile surfaces and is often held only by weak physical forces. For instance, treatment of textiles with silicones containing amino or quaternary functional groups can result in benefits that display some durability. However, these polymers are believed to bond ionically or through hydrogen bonding with cellulosic surfaces. Because the interactive forces are weak, the benefits of silicone treatments are often short lived.
It is therefore desirable to produce silicone compositions which can be used to treat textiles and provide durable benefits. Thus, silicone products are constantly being sought which can both adhere durably to textiles as well as impart textile benefits appreciated by consumers.
The present invention provides a method for treating a cellulose-containing substrate comprising contacting a silicone composition comprising at least one polysiloxane or silicone resin containing at least one functional group comprising at least one dialkylacetal group, at least one anhydride group, at least one reactive group, or combinations thereof with the cellulose-containing substrate; and
curing the silicone composition on the cellulose-containing substrate at a temperature in a range between about 25xc2x0 C. and about 200xc2x0 C.
The present invention further provides a formulation comprising an aqueous mixture or non-aqueous mixture of at least one polysiloxane or silicone resin containing at least one functional group comprising at least one dialkylacetal group, at least one anhydride group, at least one reactive group, or combinations thereof and optionally, at least one catalyst;
wherein the formulation adheres to a cellulose-containing substrate when the formulation is cured at a temperature in a range between about 25xc2x0 C. and about 200xc2x0 C. when the formulation is applied to the cellulose-containing substrate.
The present invention includes a silicone composition which includes at least one polysiloxane or silicone resin containing at least one functional group capable of interacting with cellulose. The functional group in the silicone composition of the present invention enables adhesion of the polysiloxane or silicone resin to cellulose-containing surfaces under surface treatment conditions. The functional group comprises at least one dialkylacetal group, at least one anhydride group, at least one reactive group, or combinations thereof.
The present invention includes silicone compositions having the formula:
MaMxe2x80x2bDcDxe2x80x2dTeTxe2x80x2fQg
where the subscripts a, b, c, d, e, f and g are zero or a positive integer, subject to the limitation that the sum of the subscripts b, d and f is at least one; where M has the formula:
R13SiO1/2,
Mxe2x80x2 has the formula:
xe2x80x83(X)hR23-hSiO1/2,
D has the formula:
R32SiO2/2,
Dxe2x80x2 has the formula:
(X)(2-i)Ri4SiO2/2,
T has the formula:
R5SiO3/2,
Txe2x80x2 has the formula:
(X)SiO3/2,
and Q has the formula SiO4/2, where subscript h is in a range between 1 and 3; subscript i is 0 or 1; each R1, R2, R3, R4, R5 is independently at each occurrence a hydrogen atom, C1-30 alkyl, C1-22 alkoxy, C2-22 alkenyl, C6-14 aryl, C6-22 alkyl-substituted aryl, or C6-22 aralkyl, any of which groups may be halogenated, for example, fluorinated to contain fluorocarbons such as C1-22 fluoroalkyl, or may contain amino groups to form aminoalkyls, for example aminopropyl or aminoethylaminopropyl, or may contain polyether units of the formula (CH2CHR6O)k where R6 is independently in each repeat unit CH3 or H and xe2x80x9ckxe2x80x9d is in a range between about 4 and about 50; X, independently at each occurrence, represents a functional group that is capable of causing durable interactions with cellulose-containing substrates. The term xe2x80x9calkylxe2x80x9d, as used in various embodiments of the present invention, is intended to designate both normal alkyl, branched alkyl, aralkyl, and cycloalkyl radicals. Normal and branched alkyl radicals are preferably those containing in a range between about 1 and about 30 carbon atoms, and include as illustrative non-limiting examples methyl, ethyl, propyl, isopropyl, butyl, tertiary-butyl, pentyl, neopentyl, hexyl, and dodecyl. Cycloalkyl radicals represented are preferably those containing between about 4 and about 12 ring carbon atoms. Some illustrative non-limiting examples of these cycloalkyl radicals include cyclobutyl, cyclopentyl, cyclohexyl, methylcyclohexyl, and cycloheptyl. Preferred aralkyl radicals are those containing between about 7 and about 14 carbon atoms. These include, but are not limited to, benzyl, phenylbutyl, phenylpropyl, and phenylethyl. Aryl radicals used in the various embodiments of the present invention are preferably those containing between about 6 and about 20 ring carbon atoms and contain at least one monocyclic or polycyclic moiety wherein a polycyclic may comprise fused or linked rings. Some illustrative non-limiting examples of these aryl radicals include phenyl, biphenyl, and naphthyl. An illustrative non-limiting example of a suitable halogenated moiety is trifluoropropyl.
According to the present invention, one important class of functional groups that is capable of causing durable interactions with cellulose-containing substrates is the dialkylacetal group. These groups have the general formula:
wherein R7 and R8 are alkyl groups as defined above for R1, R2, R3, R4 and R5 and where j is in a range between about 2 and about 10. The carbon-carbon bonds can be interrupted by aryl groups or other ring structures. Aryl groups used in the various embodiments of the present invention are preferably those containing in a range between about 6 and about 20 carbon atoms and containing at least one monocyclic or polycyclic moiety wherein a polycyclic may comprise fused or linked rings. The aryl groups also may incorporate one or more substituents that are compatible with the applications described in this invention. Exemplary substituents include but are not limited to halogens, alkyls, aralkyls, alkaryls, aryls, alkoxy groups, and aryloxy groups.
In another embodiment of the present invention, xe2x80x9creactive groupxe2x80x9d as used herein includes any C1-C250 alkyl, aryl, or alkylaryl group where the C1-250 group can be interrupted by or substituted with aromatic groups or aromatic-containing groups and which contains a leaving group that is capable of interacting with cellulose. The C1-250 group may also contain one or more heteroatoms such as O, N, or S. Furthermore, the C1-250 group may be unsubstituted or substituted with heteroatoms such as halogen. An exemplary reactive group comprises a chlorobenzyl moiety. Other examples of reactive groups of the present invention include, but are not limited to:
where
r is in a range between about 1 and about 10, preferably 2 or 3;
s is in a range between about 0 and about 100, preferably 4 to 20;
t is in a range between about 0 and about 100, preferably in a range between about 0 and about 20, and most preferably 0;
u is in a range between about 1 and about 10, preferably 1;
v is in a range between about 1 and about 10, preferably 2 or 3;
w is 1 or 2;
x is 1 or 2;
Z is O, NOH, NOR or NR, preferably O;
L is a leaving group;
wherein R is independently at each occurrence hydrogen (H), C1-30 alkyl, C1-22 alkoxy, C2-22 alkenyl, C6-14 aryl, C6-22 alkyl-substituted aryl, or C6-22 aralkyl where the C can be unsubstituted or substituted with heteroatoms such as oxygen (O), nitrogen (N), sulfur (S) or halogen;
wherein R9 is independently at each occurrence hydrogen (H), C1-30 alkyl, C1-22 alkoxy, C2-22 alkenyl, C6-14 aryl, C6-22 alkyl-substituted aryl, C6-22 aralkyl, or fused ring system which may or may not be fused to the phenyl group where the C can be unsubstituted or substituted with heteroatoms such as O, N, S or halogen. R9 is preferably H. If R9 represents an aryl group, it can be fused to the ring in Formulas (I) through (IV);
A is O, NOH, NOR, NR or S, preferably O;
B is O, NOH, NOR, NR or S, preferably O or NR and most preferably O;
and where the polysiloxane or the silicone resin is bound to the (CR2)r (Formula I and II), (CR2)v (Formula III), or (CR2)w (Formula IV). Any of the linker structures shown in Formulas (I) through (IV) can also be interrupted with cycloaliphatic rings or aromatic rings. Substituents on the phenyl group of formulas (I), (II), (III), and (IV) may be present at any free valence site. The polysiloxane or silicone resin may or may not contain other functionalities by substitution at silicon atoms either the same as or distinct from those bound to the reactive groups described above, such as amine-, polyether-, alkyl-, or heteroalkyl-containing groups.
Illustrative leaving groups (L) include halides such as chloride, bromide and iodide; tosylate, mesylate, phosphate; cyclic leaving groups (that is, those in which the leaving group remains bound to the fragments illustrated as bound to L in formulas I-IV) or other cyclic leaving groups containing at least one heteroatom; and other leaving groups known to those skilled in the art. Preferred leaving groups are bromide, chloride, and iodide.
In an additional embodiment of the present invention, the polysiloxane or silicone resin is substituted with one or more anhydride groups. The anhydride of the present invention typically includes, for example, five membered ring anhydrides and six membered ring anhydrides. Five membered ring anhydrides are preferred. Examples include succinic, maleic and phthalic anhydrides as well as nadic anhydride (cis-5-norbornene-endo-2,3-dicarboxylic anhydride) and benzophenone tetradicarboxylic anhydride. Any group which can be chemically bound to a polysiloxane or silicone resin and which contains a five membered ring anhydride is suitable. Importantly, also covered in the scope of this invention is the substitution of a polysiloxane or silicone resin with one or more groups that are capable of forming an anhydride under substrate treatment or cure conditions.
The number of functional groups on a polysiloxane or silicone resin in the composition that are capable of causing durable interactions with cellulose-containing substrates is at least one. In preferred embodiments the average number of functional groups on a polysiloxane or silicone resin is in a range between about 1 and about 100, more preferably in a range between about 1 and about 20, still more preferably in a range between about 2 and about 10.
The polysiloxanes or silicone resins of the present invention are typically prepared by the hydrosilylation of an organohydrogen silicone and an unsaturated molecular precursor to the dialkylacetal group, reactive group, anhydride functional group, or combination thereof wherein the organohydrogen silicone has the formula:
MaMHbDcDHdTeTHfQg
where the subscripts a, b, c, d, e, f and g are zero or a positive integer, subject to the limitation that the sum of the subscripts b, d and f is one or greater; M, D, T and Q are defined as above;
MH has the formula:
R23-hHhSiO1/2,
DH has the formula:
H2-1R41SiO2/2,
TH has the formula:
HSiO3/2,
where each R2 and R4 is independently as defined above; and subscript h and subscript i are defined above.
Hydrosilylation is typically accomplished in the presence of a suitable hydrosilylation catalyst. The catalysts preferred for use with these compositions are described in U.S. Pat. Nos. 3,715,334; 3,775,452; and 3,814,730 to Karstedt. A preferred catalyst contains platinum. Persons skilled in the art can easily determine an effective amount of platinum catalyst. Generally, an effective amount is in a range between about 0.1 parts per million and about 100 parts per million of the total silicone composition.
The organohydrogen silicone compounds that are the precursors to the compounds of the present invention may be prepared by the process disclosed in U.S. Pat. No. 5,420,221. The ""221 patent discloses the redistribution of polydimethylsiloxane polymers with organohydrogen silicone polymers and optionally, added chain stopper, to provide a silicone with randomly-distributed hydride groups using a Lewis acid catalyst, preferably a phosphonitrilic compound. Hydride-terminated polymers can be made in related equilibration reactions.
Synthesis of the polysiloxane or silicone resin may also be performed by other methods known to those skilled in the art, for example, the hydrosilylation of a monomer such as methyldichlorosilane could be followed by co-hydrolysis with the appropriate dialkyldichlorosilane and optionally, chlorotrimethylsilane.
It is to be noted that as pure compounds, the subscripts describing the organohydrogen siloxane precursor and the hydrosilylation adduct of the present invention are integers as required by the rules of chemical stoichiometry. The subscripts will assume non-integral values for mixtures of compounds that are described by these formulas. The restrictions on the subscripts heretofore described for the stoichiometric subscripts of these compounds are for the pure compounds, not the mixtures.
The polysiloxane or silicone resin typically has a molecular weight in a range between about 100 and about 6,000,000, preferably in a range between about 250 and about 150,000, more preferably in a range between about 500 and about 100,000, and most preferably in a range between about 500 and about 75,000.
In one embodiment of the present invention, a polysiloxane- or silicone resin-containing composition includes a preponderance of a specific linear, branched, cross-linked, or cyclic polysiloxane or silicone resin. In other embodiments of the present invention, a polysiloxane- or silicone resin-containing composition comprises a mixture of polysiloxanes, mixture of silicone resins, or mixtures of polysiloxanes and silicone resins which may include linear, branched, cross-linked, and cyclic species. Also, suitable compositions may comprise one or more polysiloxanes, silicone resins, and mixtures thereof which may contain adventitious amounts of other species at a level in a range between about 0.0001 wt % and about 5 wt % based on total silicon-containing species, for example, arising during the synthesis process for said polysiloxanes or silicone resins. In illustrative examples, suitable compositions may contain adventitious amounts of D4, or species containing Sixe2x80x94H, Sixe2x80x94OH, Sixe2x80x94O-alkyl bonds, and mixtures thereof.
Silicone compositions of the present invention that include at least one polysiloxane or silicone resin and at least one functional group typically impart durable benefits to materials such as textiles, including cellulose-containing surfaces such as natural fibers and regenerated fibers including blends. A particular advantage of the present invention is that the described functional groups enable the silicone composition to adhere to a cellulose-containing surface.
The silicone compositions can be delivered to a substrate, for example a cellulose-containing surface, from any appropriate aqueous or non-aqueous formulation, for example a water mixture or a water and catalyst mixture which can contain the silicone composition in a range between about 0.01% by weight and about 99% by weight based on the total formulation. The silicone composition may also be applied to the substrate as the neat material. Typically, the formulation may also include a catalyst, a typical example of which is an acid or a base. The catalyst is typically present in a range between about 0.01% and about 15% by weight based on the total formulation.
After application of the silicone composition onto the substrate, the composition can be cured over a period in a range between about 5 minutes and about 2 hours. Typically, the cure temperature is in a range between about 25xc2x0 C. and about 200xc2x0 C. Alternatively, the substituted silicone or silicone resin can be applied to the substrate neat and cured in the same manner.

Silicone compositions for textile applications


Described herein are compounds that are farnesoid X receptor agonists, methods of making such compounds, pharmaceutical compositions and medicaments comprising such compounds, and methods of using such compounds in the treatment of conditions, diseases, or disorders associated with farnesoid X receptor activity.

Farnesoid X receptor (FXR) is a nuclear receptor highly expressed in the liver, intestine, kidney, adrenal glands, and adipose tissue. FXR regulates a wide variety of target genes involved in the control of bile acid synthesis and transport, lipid metabolism, and glucose homeostasis. FXR agonism is a treatment modality for many metabolic and liver conditions.

This patent is subject to a terminal disclaimer.

Farnesoid X receptor agonists and uses thereof


An ESD protection structure has: a first P-type semiconductor region connected to a pad; a first N-type semiconductor region coupled with the first P-type semiconductor region; a second P-type semiconductor region coupled with the first N-type semiconductor region and connected to a ground terminal; a second N-type semiconductor region coupled with the second P-type semiconductor region and connected to a ground terminal; and a trigger circuit configured to draw a trigger current from the first N-type semiconductor region when a surge is applied to the pad. The trigger circuit is connected to the first N-type semiconductor region through a resistive element.

1. Field of the Invention
The present invention relates to a semiconductor device. In particular, the present invention relates to a semiconductor device provided with an electrostatic discharge (ESD) protection circuit that protects destruction of an internal circuit due to an ESD stress or an application of a surge.
2. Description of the Related Art
An ESD protection circuit is incorporated in a semiconductor integrated circuit so as to protect an internal circuit against a surge applied to an input and output pad. One of well-known topologies of the ESD protection circuit is a circuit topology using a silicon controlled rectifier (SCR). Japanese Laid Open Patent Application (JP-P2003-203985A) discloses an ESD protection circuit using an SCR. FIG. 1 is a cross-sectional view showing a structure of the ESD protection circuit disclosed in the patent document.
As shown in FIG. 1, the ESD protection circuit within the public domain has an SCR region 2 and a trigger circuit region 3 which are integrated on a P-type semiconductor substrate 1. The trigger circuit region 3 is isolated from the SCR region 2 by an STI (shallow trench isolation) layer 4 as an insulator.
An N-well 5 is formed in the SCR region 2, and an N+ diffusion layer 6 and a P+ diffusion layer 7 are formed in a surface portion of the N-well 5. Further, an N+ diffusion layer 8 and a P+ diffusion layer 9 are formed in a portion of the SCR region 2 outside of the N-well 5. The N+ diffusion layer 6, the P+ diffusion layer 7, the N+ diffusion layer 8 and the P+ diffusion layer 9 are isolated from one another by STI layers 10 as insulators. The P+ diffusion layer 7, the N-well 5, a portion near a surface of the P-type semiconductor substrate 1, and the N+ diffusion layer 8 function as an SCR having a pnpn structure. More specifically, the P+ diffusion layer 7 functions as an anode of the SCR, the N-well 5 functions as a base thereof, and the N+ diffusion layer 8 functions as a cathode thereof. On the other hand, the N+ diffusion layer 6 and the P+ diffusion layer 9 function as contact layers for realizing electrical connections to the N-well 5 and the P-type semiconductor substrate 1, respectively. The P+ diffusion layer 7 is connected to an input and output (I/O) pad 11 used for inputting and outputting a signal to and from an internal circuit (not shown). The N+ diffusion layer 8 and the P+ diffusion layer 9 are connected in common to a grounding terminal 12.
The trigger circuit region 3 is a region in which a trigger circuit that turns on the above-mentioned SCR when a surge is applied to the I/O pad 11 is formed. In the ESD protection circuit shown in FIG. 1, an NMOS transistor 13 having a source and a gate connected in common to the grounding terminal 12 is used as the trigger circuit. More specifically, a source region 14 and a drain region 15 of N+ conductive type are formed in a surface portion of the P-type semiconductor substrate 1. Further, a gate insulating layer 16 is formed on the surface of the P-type semiconductor substrate 1, and a gate electrode 17 is formed on the gate insulating layer 16. The gate electrode 17 typically includes a polysilicon layer 17a and a silicide layer 17b formed on the polysilicon layer 17a. Examples of the silicide layer 17b include a titanium silicide layer, a cobalt silicide layer, and a tungsten silicide layer. The drain region 15 is electrically connected to the N+ diffusion layer 6 in the SCR region 2 through a metal wiring 18. The source region 14 and the gate electrode 17 are connected to the grounding terminal 12.
FIG. 2 shows an equivalent circuit of the ESD protection circuit shown in FIG. 1. The ESD protection circuit shown in FIG. 1 equivalently functions as a circuit that includes a PNP transistor 21, an NPN transistor 22, a substrate resistance RSUB, an N-well resistance RNW and the NMOS transistor 13. An emitter of the PNP transistor 21 is connected to the I/O pad 11, a collector thereof is connected to the grounding terminal 12 through the substrate resistance RSUB, and a base thereof is connected to a collector of the NPN transistor 22. A base of the NPN transistor 22 is connected to the collector of the PNP transistor 21, and an emitter thereof is connected to the grounding terminal 12. With regard to the NMOS transistor 13 that functions as the trigger circuit, a drain thereof is connected to the base of the PNP transistor 21 through the N-well resistance RNW and the metal wiring 18, and a source and a gate thereof are connected to the grounding terminal 12.
When a surge voltage is applied to the I/O pad 11, the ESD protection circuit shown in FIG. 1 operates as follows to protect the internal circuit. When the surge voltage is applied to the I/O pad 11, the surge voltage is applied to the drain of the NMOS transistor 13 through the emitter and base of the PNP transistor 21. If the surge voltage causes breakdown of the NMOS transistor 13, then a trigger current flows from the base of the PNP transistor 21 toward the grounding terminal 12, and the PNP transistor 21 is thereby turned on. When the PNP transistor 21 is turned on, an emitter-collector current flows from the emitter to the collector of the PNP transistor 21. The emitter-collector current flows into the grounding terminal 12 through the substrate resistance RSUB. When the emitter-collector current flows through the substrate resistance RSUB, a base potential of the NPN transistor 22 is increased due to a voltage drop at the substrate resistance RSUB. When the base potential of the NPN transistor 22 is increased, a base current flows in the NPN transistor 22, and the NPN transistor 22 is thereby turned on. When the NPN transistor 22 is turned on, the surge voltage applied to the I/O pad 11 is discharged through the NPN transistor 22, and thus the internal circuit is protected.
The ESD protection circuit shown in FIG. 1 is advantageous in that a high discharge capability and a low trigger voltage can be simultaneously ensured because the SCR and the trigger circuit are isolated from each other. Specifically, the ESD protection circuit shown in FIG. 1 has the following advantages. First, since the SCR is isolated from the trigger circuit, a length of the base of the SCR can be designed to be small. This can enhance the discharge capability of the ESD protection circuit. Secondly, since the trigger circuit can be designed irrespective of the SCR, the trigger voltage can be arbitrarily designed in the ESD protection circuit shown in FIG. 1. This means that the ESD protection circuit shown in FIG. 1 satisfies both the high discharge capability and the low trigger voltage.

ESD protection circuit with SCR structure for semiconductor device


An electronic device may include an elongated dielectric substrate having opposing first and second ends, a plurality of conductive pads longitudinally spaced apart along the elongated dielectric substrate, and a plurality of silicon carbide (SiC) (e.g., PiN) diode dies. Each SiC die may have bottom and top diode terminals and may be mounted on a respective conductive pad with the bottom diode terminal in contact therewith. The electronic device may further include at least one internal wirebond between the corresponding conductive pad of one SiC diode die and the top diode terminal of a next SiC diode die, a first external lead electrically coupled to the top diode terminal of a first SiC die and extending longitudinally outwardly from the first end, and a second external lead electrically coupled to the corresponding contact pad of a last SiC diode die and extending longitudinally outwardly from the second end.

Voltage multipliers are used to create a relatively high DC voltage from an AC power source. Such devices are used in a variety of applications ranging from particle accelerators to more commonplace electronic devices such as photocopiers.
One particular application in which particle accelerators are used is for nuclear-based borehole logging measurements in hydrocarbon resource wells (e.g., oil or natural gas wells). One such miniature, borehole-size particle accelerator is a neutron generator which utilizes the fusion of deuterium and tritium ion at high (100 keV) energies. This device irradiates the formation with 14 MeV neutrons which can be reflected and/or attenuated and, when measured, provide an indication of the hydrogen content of the formation; alternately, the stimulated gamma radiation response from the formation can be measured to provide, among other, an elemental composition of the formation.

Electronic device including silicon carbide diode dies


Disclosed herein is a release paper comprising:

The present invention relates to a release paper. More particularly, the present invention relates to a release paper which comprises a release layer of a specified 4-methyl-1-pentene resin and which can be appropriately used in, for example, production of a synthetic leather.
Generally, synthetic leathers are produced by first coating a release paper having a relief pattern on its surface with a base resin such as polyurethane resin in liquid form, subsequently effecting drying to thereby obtain a resin layer on the release paper, thereafter bonding a base material such as cloth to the resin layer, and finally removing the release paper. The surface of thus produced synthetic leathers is in such a condition that the relief pattern of the surface of release paper has been transferred thereto.
The release paper for use in the above production of synthetic leathers must have excellent heat resistance and release capability. Therefore, in the release paper, a 4-methyl-1-pentene polymer whose melting point is as high as about 220 to 240xc2x0 C. is used as a principal component of a release layer formed on a base such as paper.
For example, a paper base overlaid with poly-4-methyl-1-pentene by extrusion laminating is used as the release paper for synthetic leather. In the production of this release paper for synthetic leather, the release layer is embossed so that desired pattern is provided on the surface of the release layer. The intended synthetic leather can be produced by casting a resin for synthetic leather over the surface of the release layer and hardening the resin.
A release paper for synthetic leather production comprising a paper base laminated with a release layer constituted of a 4-methyl-1-pentene polymer composition comprising 80 to 97 parts by weight of 4-methyl-1-pentene polymer (A) and 3 to 20 parts by weight of ethylene/ethyl acrylate copolymer (B), was proposed in Japanese Patent Laid-open Publication No. 8(1996)-25580. According to this publication, the release layer of the release paper has excellent heat resistance and wettability, so that the release paper can be appropriately used even in the production of a synthetic leather from a water soluble or water dispersible resin.
There has been such a problem that, when the release paper is repeatedly used in the production of a synthetic leather or the like, the release paper curls into cylindrical form. Upon curling of the release paper, the work efficiency is poor in the reuse of the release paper, and, when forced elimination of curling is intended, the surface of the release paper may suffer from flaw or microcracking to thereby cause the reuse thereof to be difficult. The greater the thickness of the release layer of the release paper, the more serious the tendency toward these problems.
Therefore, there has been a strong demand for the development of a repeatedly usable release paper which is excellent in heat resistance and exhibits less curling tendency in repeated use and which exhibits a high bonding strength between resin and paper.
It is an object of the present invention to provide a release paper which is excellent in heat resistance and exhibits less curling tendency in repeated use, which exhibits a high bonding strength between resin and paper and is excellent in durability, and which is suitable for use in, for example, production of a synthetic leather.
The release paper of the present invention comprises:
a paper base laminated with a release layer,
the release layer comprising a 4-methyl-1-pentene resin being a copolymer of 4-methyl-1-pentene and an xcex1-olefin other than 4-methyl-1-pentene wherein the xcex1-olefin is contained in a proportion of 6 to 8% by weight.
With respect to the release paper of the present invention, it is preferred that the xcex1-olefin have 10 to 20 carbon atoms. Preferably, the release paper is for use in production of a synthetic leather.
The present invention will be described in detail below.
The release paper of the present invention comprises a paper base laminated with a release layer. Only one side of the paper base may be laminated with the release layer. Alternatively, both sides of the paper base may be laminated with the release layer.
 less than Release Layer greater than
The release layer as a constituent of the release paper of the present invention comprises a 4-methyl-1-pentene resin being a copolymer of 4-methyl-1-pentene and an xcex1-olefin other than 4-methyl-1-pentene wherein the xcex1-olefin is contained in a proportion of 6 to 8% by weight.
The xcex1-olefin other than 4-methyl-1-pentene for constituting the 4-methyl-1-pentene resin can be, for example, any of xcex1-olefins having 2 to 20 carbon atoms, such as ethylene, propylene, 1-butene, 1-hexene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene and 1-eicocene. At least one of these can be employed. Among them, an xcex1-olefin having 10 to 20 carbon atoms is preferred. In particular, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene and 1-eicocene are especially preferred.
It is preferred that the 4-methyl-1-pentene resin be a copolymer of 4-methyl-1-pentene and an xcex1-olefin having 2 to 20 carbon atoms, especially 10 to 20 carbon atoms, from the viewpoint that the obtained release paper is highly flexible and is excellent in heat resistance.
In the 4-methyl-1-pentene resin for constituting the release layer in the present invention, the xcex1-olefin is contained in a proportion of 6 to 8% by weight, preferably 6 to 7% by weight.
When the xcex1-olefin content of the 4-methyl-1-pentene resin is as low as less than 6% by weight, the crystallinity and orientation coefficient of the 4-methyl-1-pentene resin tend to exhibit unfavorably large values. When the release paper including the release layer constituted of such 4-methyl-1-pentene resin is used in the production of a synthetic leather, the release layer may unfavorably be shrunk by heating in the process for producing the synthetic leather to thereby cause the release paper to curl.
On the other hand, when the xcex1-olefin content of the 4-methyl-1-pentene resin is as high as more than 8% by weight, the heat resistance of the release layer resin may be unsatisfactory. When the release paper including the release layer constituted of such resin is used in the production of a synthetic leather, the embossed pattern provided on the release layer may unfavorably be flowed by heating in the process for producing the synthetic leather to thereby cause the repeated use of the release paper to be infeasible.
When the xcex1-olefin content of the 4-methyl-1-pentene resin is in the range of 6 to 8% by weight, these problems can favorably be avoided to thereby enable the repeated use of the release paper.
With respect to the 4-methyl-1-pentene resin for use in the present invention, it is preferred that the melt flow rate (MFR) thereof as measured under a load of 5.0 kg at 260xc2x0 C. according to ASTM D1238 be in the range of 1 to 400 g/10 min, especially 20 to 300 g/10 min, and still especially 50 to 200 g/10 min. The use of such 4-methyl-1-pentene resin is preferred from the viewpoint that laminating can be efficiently conducted at a high speed to thereby enhance the productivity of release paper, that a uniform thickness can be realized and the release layer can be free from cracking, and that a release paper which is excellent in the bonding strength between the release layer and the paper base layer can be easily produced.
In the present invention, the 4-methyl-1-pentene resin for constituting the release layer can be produced by copolymerizing 4-methyl-1-pentene and at least one of the above xcex1-olefins according to known processes.
In the present invention, the 4-methyl-1-pentene resin may contain various additives customarily incorporated in polyolefins according to necessity in an amount not detrimental to the object of the present invention. Also, the 4-methyl-1-pentene resin may contain a small amount of resins other than the 4-methyl-1-pentene resin. Examples of the additives include a silane coupling agent, a weathering stabilizer, a thermal stabilizer, a slip agent, a nucleating agent, a pigment and a dye.
The thickness of the release layer of the 4-methyl-1-pentene resin, although not particularly limited, is preferably in the range of generally 5 to 200 xcexcm, especially 20 to 100 xcexcm. When the thickness of the release layer is in these preferable ranges, there may be obtained a satisfactory release property to a resin, such as the resin for synthetic leather, and, even if the smoothness of paper base is poor, the release layer can have smooth surface with the result that a synthetic leather of good surface condition can be obtained by the use of the release paper.
Thus formed release layer is excellent in the adherence to a paper base and in heat resistance, and exhibits a low resin orientation and a low crystallinity. The release paper of the present invention having such release layer is characterized by low shrinkage when exposed to heat in the production of a synthetic leather, less curling tendency upon repeated use, less pattern disappearing tendency, high bonding strength and prolonged durability.
 less than Paper Base greater than
In the present invention, a kraft paper, a wood free paper, a simili paper, an art paper, a coated paper or the like is used as the paper base. The thickness of the paper base, although not particularly limited, is preferably in the range of generally about 50 to 1000 xcexcm, especially 100 to 350 xcexcm.
 less than Release Paper greater than
The release paper of the present invention comprises the above paper base laminated with the release layer of the 4-methyl-1-pentene resin. Only one side of the paper base maybe laminated with the release layer. Alternatively, both sides of the paper base may be laminated with the release layer. The release paper of the present invention, although may be produced by any method, is preferably produced by laminating the paper base with the resin for constituting the release layer according to the extrusion laminating method. Further, the release paper of the present invention may have embossed pattern. The embossed pattern may be provided during the laminating of the paper base with the release layer or after the laminating. The embossed pattern can appropriately be provided by the use of customary embossing techniques.
According to necessity, the mixing of 4-methyl-1-pentene resin for constituting the release layer and optionally incorporated various additives can be performed by conventional methods using a mixer or a kneader. The employable mixer can be, for example, a V blender, a ribbon blender, a Henschel mixer or a tumbler blender. The employable kneader can be, for example, a single-screw extruder, a double-screw extruder, a kneader or a Banbury mixer.
The release paper of the present invention is preferably prepared by laminating the paper base with the release layer. In particular, it is preferred that the paper base be overlaid with the 4-methyl-1-pentene resin for constituting the release layer by extrusion lamination molding. The extrusion lamination molding can be accomplished by, for example, extruding the 4-methyl-1-pentene resin in molten form on the paper base by extrusion coating by means of customary extrusion laminators such as a single extrusion laminator or a coextrusion laminator. By this manner, the paper base can be laminated with the 4-methyl-1-pentene resin. The release paper obtained by laminating the paper base with the release layer by the extrusion lamination molding exhibits especially excellent bonding strength to thereby exhibit less tendency to invite peeling or other drawbacks even in the repeated use as the release paper for synthetic leather production or the like. Hence, the release paper ensures excellent durability.
The release paper of the present invention, by virtue of the structure wherein the paper base is laminated with the release layer constituted of the 4-methyl-1-pentene resin having an xcex1-olefin content of 6 to 8% by weight, is characterized by reduced orientation of the release layer resin, low crystallinity thereof, less shrinkage when exposed to heating in the use in synthetic leather production or the like, satisfactory release property, excellent heat resistance, reduced curling even after repeated use and excellent durability.
The above release paper of the present invention is suitable for use in the production of a synthetic leather.
The present invention enables providing a release paper which is excellent in heat resistance and exhibits less curling tendency in repeated use, which exhibits a high bonding strength between resin and paper, and is excellent in durability, and which is suitable for use in, for example, production of a synthetic leather.

Abstract: this release layer comprising a 4-methyl-1-pentene resin being a copolymer of 4-methyl-1-pentene and an xcex1-olefin other than 4-methyl-1-pentene wherein the xcex1-olefin is contained in a proportion of 6 to 8% by weight. This release paper is excellent in heat resistance and exhibits less curling tendency in repeated use. Further, the release paper exhibits a high bonding strength between resin and paper, and is excellent in durability. The release paper is suitable for use in, for example, production of a synthetic leather.


A combination blade assembly is designed for use with a riding type lawn mower and the like. The combination blade assembly modifies the riding type lawn mower into a mulcher and chipper without prohibiting the lawn mower from being used for cutting grass. The combination blade assembly is permanently installed on the riding type lawn mower which eliminates the need for additional equipment. Due to the nature of the riding type lawn mower, the combination blade assembly creates a very mobile mulcher and chipper.

1. The Field of Invention
The present invention relates generally to a combination blade assembly that is attached to the blade shaft of a riding type power lawn mower to modify the mower for mulching and chipping. More specifically, the present invention relates to a combination blade assembly which modifies the riding type power lawn mower to be used for mulching and chipping of branches, brush and tough organic materials in addition to the grass cutting capabilities of the mower, without repeated conversion of the mower after the initial installation of the combination blade assembly on the mower.
2. History of Prior Art
The present prior art provides devices designed primarily for relatively lightweight use in a home garden of soft refuse, yet at the same time provides an efficient shredding and mulching machine enabling such refuse to be chopped finely enough to be incorporated back into the garden if desired, and is also readily converted for use as a lawn mower when desired.
It is often desirable that a riding type power lawn mower is capable of not only cutting grass, leaves and lightweight organic matter, but also possess mulching and chipping capabilities for heavy-weight branches, brush and tough organic materials.
Patents reviewed have disclosed several devices for mulching and chipping organic matter. Many such devices are free standing mulchers and chippers, while other devices are designed to be used with or to modify rotary type power lawn mowers.
The Bendig U.S. Pat. No. 4,796,416, shows a mulching attachment having an upper blade with a spacer coupled to a lower blade and base plate. This blade assembly is used with a rotary type power lawn mower for mulching light-weight organic matter. However, the Bendig patent requires extensive disassemblage of the mower when it is desirable to attach the blade assembly for the conversion of the mower to a mulcher. This conversion prohibits the mower to be used consecutively for cutting grass. Additionally, the Bendig patent requires partial removal of the blade assembly from the mower when it is desirable to use the mower for cutting grass. The required conversion of the mower to a mulcher and back to a mower is time consuming and too laborious for the operator.
The Leuz U.S. Pat. No. 4,901,509, shows a funnel-shaped chute attachment for a rotary type power lawn mower. The device converts the mower to a garden mulcher. This conversion does not allow the mower to be used consecutively for cutting grass. The funnel-shaped attachment must first be removed from the mower, and a coverplate placed over the opening in the mower deck and further disassembling of the mower blade and reassembling of the blade when it is desirable to use the mower for cutting grass. Additionally the Leuz patent was designed specifically for modifying a rotary type power lawn mower to a mulcher of light-weight garden materials.
The Brokaw U.S. Pat. No. 4,057,952, shows a rotary type power lawn mower with chipping and mulching capabilities due to a set of three blades attached to a vertical drive shaft. The three blades include a top chopping blade, a middle shredder blade, and bottom mower blade. The chipping blade is described as being much heavier than the mower blade and acts as a fly wheel to provide increased cutting energy as compared to the horse power of the mower. However, the Brokaw patent assemblage involves a number of parts making the adaption cost prohibitive and too difficult for the average mower owner to assemble. A bottom plate is secured to the mower while being used as a mulcher, this bottom plate prohibits the mower from being used consecutively for cutting grass. The Brokaw patent is also susceptible for organic materials to become lodged in the chopping assembly of the feed roller, as well as the chopping blades. Additionally, due to the complex design, the blade assembly is not suitable for utilization with a riding type power lawn mower.
The Haas U.S. Pat. No. 4,083,166, shows a mulcher attachment comprised of a lightweight circular disc blade with a plurality of openings and blade portions for use with a rotary type power lawn mower that shreds and mulches the lightweight organic materials produced during operation of the mower. However, due to the upward suction of organic materials through the openings of the circular disc blade, the Haas patent is not capable of mulching or shredding large, heavy-weight materials. Whatever the precise merits, features and advantages of the above cited references, none of them achieves or fulfils the purposes of a combination blade assembly as accomplished by the present invention.

Combination chipper and grass cutting blade assembly for riding type lawn mowers and the like


Techniques for establishing a fine timing measurement (FTM) session of infinite duration between wireless devices is provided. A method according to these techniques includes generating, at a first wireless device, a first request to establish an FTM session with a second wireless device using an FTM protocol, the first request comprising one or more session parameters having a value indicative that the first wireless device is requesting the FTM session have an infinite session duration, receiving one or more FTM measurement messages from the second wireless device, and sending a second request to the second wireless device requesting that the FTM session be terminated.

Mobile wireless devices can use ranging techniques to determine their location relative to other wireless devices at known locations. Ranging information can be used to provide for location-based services to the mobile wireless device, to select a wireless access point or wireless base station to provide network connectivity to the mobile wireless device, to determine the location of the mobile device where range information to multiple wireless access points, wireless base stations, or other mobile wireless devices at known locations is available. Ranging information can also be used provide other types of services to the mobile wireless device.


A spandex comprising a polyurethane or polyurethaneurea reaction product of at least one diisocyanate compound and a poly(tetramethylene-co-ethyleneether) glycol comprising constituent units derived by copolymerizing tetrahydrofuran and ethylene oxide wherein the percentage of ethylene ether moieties is from about 16 to about 70 mole percent with at least one chain extender selected from the group consisting of diamines and diols and at least one chain terminator wherein the spandex is spun at a speed in excess of about 750 meters per minute.

1. Field of the Invention
This invention relates to new spandex compositions comprising poly(tetramethylene-co-ethyleneether) glycols comprising constituent units derived by copolymerizing tetrahydrofuran and ethylene oxide, wherein the portion of the units derived from ethylene oxide is present in the poly(tetramethylene-co-ethyleneether) glycol from about 16 to about 70 mole percent and wherein the spandex filaments are spun at high speed, typically greater than 750 meters per minute.
2. Description of the Related Art
Poly(tetramethylene ether) glycols, also known as polytetrahydrofuran or homopolymers of tetrahydrofuran (THF, oxolane) are well known for their use in soft segments in polyurethaneureas. Poly(tetramethylene ether) glycols impart superior dynamic properties to polyurethaneurea elastomers and fibers. They possess very low glass transition temperatures, but have crystalline melt temperatures above room temperature. Thus, they are waxy solids at ambient temperatures and need to be kept at elevated temperatures to prevent solidification.
Copolymerization with a cyclic ether has been used to reduce the crystallinity of the polytetramethylene ether chains. This lowers the polymer melt temperature of the copolyether glycol and at the same time improves certain dynamic properties of the polyurethaneurea that contains such a copolymer as a soft segment. Among the comonomers used for this purpose is ethylene oxide, which can lower the copolymer melt temperature to below ambient, depending on the comonomer content. Use of poly(tetramethylene-co-ethyleneether) glycols may also improve certain dynamic properties of polyurethaneureas, such as elongation at break and low temperature performance, which is desirable for some end uses.
Poly(tetramethylene-co-ethyleneether) glycols are known in the art. Their preparation is described in U.S. Pat. Nos. 4,139,567 and 4,153,786. Such copolymers can be prepared by any of the known methods of cyclic ether polymerization, such as those described in "Polytetrahydrofuran" by P. Dreyfuss (Gordon & Breach, N.Y. 1982), for example. Such polymerization methods include catalysis by strong proton or Lewis acids, heteropoly acids, and perfluorosulfonic acids or acid resins. In some instances it may be advantageous to use a polymerization promoter, such as a carboxylic acid anhydride, as described in U.S. Pat. No. 4,163,115. In these cases, the primary polymer products are diesters, which then need to be hydrolyzed in a subsequent step to obtain the desired polymeric glycols.
Poly(tetramethylene-co-ethyleneether) glycols offer advantages over poly(tetramethylene ether) glycols in terms of certain specific physical properties. At ethyleneether contents above 20 mole percent, the poly(tetramethylene-co-ethyleneether) glycols are moderately viscous liquids at room temperature and have a lower viscosity than poly(tetramethylene ether) glycols of the same molecular weight at temperatures above the melting point of poly(tetramethylene ether) glycols. Certain physical properties of the polyurethanes or polyurethaneureas prepared from poly(tetramethylene-co-ethyleneether) glycols surpass the properties of those polyurethanes or polyurethaneureas prepared from poly(tetramethylene ether) glycols.
Spandex based on poly(tetramethylene-co-ethyleneether) glycols is also known in the art. For example, U.S. Pat. No. 4,224,432 to Pechhold et al. discloses the use of poly(tetramethylene-co-ethyleneether) glycols with low cyclic ether content to prepare spandex and other polyurethaneureas. Pechhold teaches that ethyleneether levels above 30 percent are preferred. Pechhold does not teach the use of coextenders, though it discloses that mixtures of amines may be used.
U.S. Pat. No. 4,658,065 to Aoshima et al. discloses the preparation of several THF copolyethers via the reaction of THF and polyhydric alcohols using heteropolyacid catalysts. Aoshima also discloses that copolymerizable cyclic ethers, such as ethylene oxide, may be included with the THF in the polymerization process. Aoshima discloses that the copolyether glycols may be used to prepare spandex, but contains no examples of spandex from poly(tetramethylene-co-ethyleneether) glycols.
U.S. Pat. No. 3,425,999 to Axelrood et al. discloses the preparation of polyether urethaneureas from poly(tetramethylene-co-ethyleneether) glycols for use in oil resistance and good low temperature performance. The poly(tetramethylene-co-ethyleneether) glycols have ethyleneether content ranging from 20 to 60 percent by weight (equivalent to 29 to 71 mole percent). Axelrood does not disclose the use of these urethaneureas in spandex. Axelrood discloses that "the chain extenders most useful in this invention are diamines selected from the group consisting of primary and secondary diamines and mixtures thereof." Axelrood further discloses that "the preferred diamines are hindered diamines, such as dichlorobenzidine and methylene bis(2-chloroaniline)." Use of ethylene diamine is not disclosed.
U.S. Pat. No. 6,639,041 to Nishikawa et al. discloses fibers having good elasticity at low temperature that contain polyurethaneureas prepared from polyols containing copolyethers of THF, ethylene oxide, and/or propylene oxide, diisocyanates, and diamines and polymers solvated in organic solvents. Nishikawa teaches that these compositions have improved low temperature performance over standard homopolymer spandexes. Nishikawa also teaches that "above about 37 mole % ethyleneether content in the copolyether glycol, unload power at low elongations is unacceptably low, elongation-at-break declines, and set rises, though very slightly." The examples in Nishikawa show that as the mole percent of ethylene ether moiety in the copolyether increases from 22 to 31 to 37 mole percent, the elongation at break rises, but upon increasing to 50 mole percent, the elongation at break then drops. In contrast, the spandex of the present invention exhibits a trend of increasing elongation at break as mole percent of ethylene ether moiety in the copolyether increases from 27 to 49 mole percent. All of the examples in this patent were spun at 650 meters/min. or less.
Spinning spandex faster to make more fiber in a given amount of time and thus reduce manufacturing cost is obvious to any fiber producer, but the spinning speed is limited by the negative effect on some of the fiber properties. It is well known to those skilled in the art that increasing the spinning speed of a spandex composition will reduce its elongation and raise its load power compared to the same spandex spun at a lower speed. Thus, the faster a spandex fiber is spun the more the elongation is reduced and the load power is increased, resulting in reduced draftability of the fiber. Reduced draftability results in requiring more spandex to be used in garment construction and thus increases the cost of garment manufacture. Therefore, it is common practice to slow spinning speeds in order to increase the elongation and reduce the load power of a spandex in order to increase its draftability in circular knitting and other spandex processing operations.
One approach to increasing productivity based on spinning techniques is disclosed in U.S. Pat. No. 6,916,896 to Selling et al. Selling describes using polyurethaneurea compositions with mixed diisocyanates to increase polymer solution solubility so that a higher solids polyurethaneurea solution may be spun. Even though higher spinning speeds are not used, productivity as measured by weight of spandex yarn produced in a given time is increased. The polyurethaneureas of the present invention also have high solution solubility without mixed diisocyanates and have much higher productivities than Selling.
Yet another approach to increased productivity through optimal spinning conditions is disclosed in JP2002-155421A "Dry-Spinning Process." JP2002-155421A discloses a method for increasing productivity in dry spinning polyurethanes. This method is based on adjusting cell spinning conditions to avoid the upward flow of drying gas in the spinning cell and avoiding threadline lateral instability. The two examples of JP2002-155421A both employ poly(tetramethylene ether) glycol-based spandex. JP2002-155421A does not disclose the types of spandexes suitable for the invention. The process of the present invention appears to be independent of spinning cell conditions beyond those necessary to produce a suitably dry fiber (e.g., 0 to 0.5 percent dimethylacetamide solvent remaining in the fiber). In addition, no additives are necessary.
The applicants have observed that spandex with poly(tetramethylene-co-ethyleneether) glycols having from about 16 to about 70 mole percent, for example from greater than about 37 to about 70 mole percent, of its constituent units derived from ethylene oxide as the soft segment base material and which is also spun at high speeds, i.e., greater than 750 meters/min., provides improved physical properties over other spandexes spun at similarly high speeds. Spandex based on other copolyether glycols such as poly(tetramethylene-co-2-methyltetramethyleneether) or polyester glycols such as the copolyester of ethylene glycol, 1,4-butylene glycol and adipic acid also have low load power. However, these spandexes also generally have low tenacity or low elongation or both that limits their ability to be spun at speeds in excess of 1000 meters/min.
The poly(tetramethylene-co-ethyleneether) glycol-based spandex of the present invention possesses the combination of low load power, high elongation, and adequate tenacity that allows it to be spun at speeds in excess of 1300 meters/min., producing a fiber with excellent draftability in circular knitting operations. In addition, the spandex of the present invention shows a desirable reduction in shrinkage in hot wet processing when it is spun at windup speeds greater than 1000 meters/min.

Spandex compositions for high speed spinning


A technique for generating virtual models of plants in a field is described. Generally, this includes recording images of plants in-situ; generating point clouds from the images; generating skeleton segments from the point cloud; classifying a subset of skeleton segments as unique plant features using the images; and growing plant skeletons from skeleton segments classified as unique plant feature. The technique may be used to generate a virtual model of a single, real plant, a portion of a real plant field, and/or the entirety of the real plant field. The virtual model can be analyzed to determine or estimate a variety of individual plant or plant population parameters, which in turn can be used to identify potential treatments or thinning practices, or predict future values for yield, plant uniformity, or any other parameter can be determined from the projected results based on the virtual model.

Identifying plants from captured images is beneficial for a number of agricultural purposes. However, individual plants are generally planted close in proximity to each other in order to maximize a desired outcome (e.g., maximize yield, protein percentage, or some other measurable quantity) while minimizing the amount of land that is needed to grow the crops. Based on this, it is common for the leaves, branches, and other growths of a plant to overlap with other nearby plants. As these growths are usually both numerous and roughly similar in appearance from plant to plant, existing image recognition systems experience difficulty when trying to identify plant matter than may appear to belong to multiple nearly overlapping plants. Often, they will mischaracterize plant growths as belonging to the wrong plant, or will misidentify how many plants are present in the field.

System and method of virtual plant field modelling