Showing papers on "Temperature coefficient published in 1982"
TL;DR: In this paper, a dense ceramic with an ordered perovskite structure with chemical formula Ba(Mg1/3Ta2/3)O3 is prepared, aiming at materials for a dielectric resonator with temperature-stable high-dielectric contsant and low loss at microwave frequency.
Abstract: A dense ceramic with an ordered perovskite structure with chemical formula Ba(Mg1/3Ta2/3)O3 is prepared, aiming at materials for a dielectric resonator with temperature-stable high dielectric contsant and low loss at microwave frequency. A small amount of Mn ion is doped to the sample to complete the sintering. The dielectric constant and unloaded Q are 25 and 16800 at 10.5 GHz respectively. The temperature coefficient of resonant frequency is estimated as 2.7 ppm/°C in the vicinity of room temperature. The value of Q we obtained is the highest among those reported so far on ceramics having a similar characteristic.
272 citations
TL;DR: The dissolution rate coefficient at early stage (K1) can be predicted as a function of temperature (T°C) and this equation will also be applied to a new approach for the fate and behavior of biogenous silica settling through a water column by introducing the term temperature into a model.
Abstract: In a study of silica dissolution from diatoms, the rate coefficient (K) h-1 of raw diatom cells was estimated as 4 to 5 times smaller than that of the acid-digested siliceous skeletons. The dissolution rate coefficient at early stage (K1) can be predicted as a function of temperature (T°C): in K1=α+βT, where α is the frequency factor depending on the properties of diatom species, ranging from -7.35 to-`0.38, and the temperature coefficient β is 0.0833 for all species. Activation energies were calculated to be 1.37 to 1.38 Kcal mol-1. This equation suggests that the rate coefficient K1 increases by a factor of 2.27 for each 10 C° rise in temperature. This equation will also be applied to a new approach for the fate and behavior of biogenous silica settling through a water column by introducing the term temperature into a model.
230 citations
TL;DR: A batch-fabricated solid-state capacitive pressure transducer has been developed using silicon integrated-circuit technology as discussed by the authors, which exhibits a dynamic range of 350 mmHg and a pressure sensitivity of about 1100 ppm/mmHg.
Abstract: A batch-fabricated solid-state capacitive pressure transducer has been developed using silicon integrated-circuit technology The fabricated devices exhibit a dynamic range of 350 mmHg and a pressure sensitivity of about 1100 ppm/mmHg The temperature coefficient of zero-pressure offset is about +50 ppm/°C (less than 005 mmHg/°C) and the temperature coefficient of pressure sensitivity over the -20 to +50°C temperature span is about +275 ppm/°C (less than 004 mmHg/°C) when the device is used with an open or vacuum-sealed reference cavity These temperature coefficients are substantially lower than those of previously reported monolithic devices and are low enough that expensive temperature trims can be eliminated for many applications
228 citations
TL;DR: In this paper, solid solution ceramics in the Ba(Zn1/3Nb2/3)O3(BZN) and SZN system have been studied with a view to finding materials for use as dielectric resonators at microwave frequency.
Abstract: Solid solution ceramics in the Ba(Zn1/3Nb2/3)O3(BZN)–Sr(Zn1/3Nb2/3)O3 (SZN) system have been studied with a view to finding materials for use as dielectric resonators at microwave frequency. The relative dielectric constant and the unloaded Q at 10 GHz are respectively 41 and 5400 for BZN, and 40 and 2000 for SZN. The temperature coefficient of the resonant frequency is estimated as 30 ppm/°C for BZN and -38 ppm/°C for SZN. The dielectric constant of 0.3 BZN–0.7 SZN ceramic is nearly independent of temperature, which gives a very small estimated temperature coefficient of the resonant frequency of -5 ppm/°C.
134 citations
TL;DR: In this article, the composition of the TiN films was measured using Rutherford backscattering analysis and the influence of substrate bias on the grain size, lattice parameter, the deposition rate, the resistivity and the temperature coefficient of resistivity was also examined.
97 citations
TL;DR: In this paper, a bandgap-voltage reference implemented with a new accurate circuit configuration for compensating the thermal nonlinearity of the base-emitter voltage is described, achieving a temperature coefficient of 0.5 ppm/spl deg/C over the temperature range -25 to +85/spl/C.
Abstract: A bandgap-voltage reference implemented with a new accurate circuit configuration for compensating the thermal nonlinearity of the base-emitter voltage is described. With this device, a temperature coefficient of 0.5 ppm//spl deg/C over the temperature range -25 to +85/spl deg/C has been achieved. The minimum required supply voltage amounts to only 5.5 V.
86 citations
01 Jan 1982
TL;DR: In this article, the temperature coefficient of delay (TCD) for surface acoustic waves (SAW) on A1N films has been investigated and a negative TCD of −30 ppm/C was reported.
Abstract: Until now, very few papers have appeared on the temperature coefficient of delay (TCD) for surface acoustic waves (SAW) on A1N films. We report that A1N has a negative TCD of \-30 ppm/"C, and that the A1N layer of appropriate thickness cancels the first-order temperature coefficient for sapphire and silicon. A1N films on sapphire substrates. A1N films were single-crystal films grown by metalorganic chemical vapor deposition. The experimental value of TCD at 25OC decreased with increasing kH (k: wave number, H; thickness of A1N film). With the (0001)AlNl (0001) [1100]~1~0~.structure a zero temperature COefficient SAW oscillator of 1.139 GHz was obtained at kH-b3.75, and with the (1120) [0001]A1N/(01~2) [0I11]Al2O3 structure a negative TCD (-7.5 ppm/'C) was obtained at kHn,3.0. Next, by computer fitting, we have determined the first-order temperature COefficients of elastic constants of AlN, and then calculated all the zero TCD characteristics of A1N/A1203, AlN/Si, AlN/SOS and A1N/Si02/Si combinations. We have measured the TCD's for
73 citations
TL;DR: In this article, an acoustic bulk wave resonator with an absolute temperature coefficient of series or parallel resonant frequency of less than 4 ppm/°C over the temperature range −20 to +120
Abstract: This letter reports on an acoustic bulk wave resonator structure having an absolute temperature coefficient of series or parallel resonant frequency of less than 4 ppm/°C over the temperature range −20 to +120 °C comparing favorably with that of conventional AT cut quartz. In addition, the resonant Q was 7600 for parallel and 7300 for series resonance at frequencies near 330 MHz for the fundamental mode. The resonator is composed of a unique composition of an AlN piezoelectric film sputtered on a single‐crystal silicon membrane for a total thickness of less than 10 μ. The resonator coupling coefficient was found to be 2.5% corresponding to film coupling of 12%. The AlN films were prepared in a dc planar magnetron reactive sputtering system.
69 citations
TL;DR: In this paper, the transition from a positive to a negative temperature coefficient of resistivity (TCR) has been studied in the artificially layered metallic system Nb-Cu and it was shown that the TCR can undergo a rather sudden change in sign from positive to negative as the layer thickness is decreased below approximately 10 A. The temperature dependence of the conductivity in the nonmetallic regime can be explained by localization-type theories.
Abstract: The transition from a positive to a negative temperature coefficient of resistivity (TCR) has been studied in the artificially layered metallic system Nb-Cu. We find the TCR to undergo a rather sudden change in sign from positive to negative as the layer thickness is decreased below approximately 10 A. The temperature dependence of the conductivity in the nonmetallic regime can be explained by localization-type theories, and implies that both localization and Coulomb effects are important in this purely metallic three-dimensional system.
64 citations
Patent•
28 Jul 1982TL;DR: In this paper, a known current source arrangement which generates a current whose temperature coefficient is only equal to zero at one specific temperature is considered, and steps are taken, in accordance with the invention, to render the generated current independent of the temperature over a wide temperature range by compensation of the disturbing factor in the relationship between generated current and the temperature.
Abstract: In a known current source arrangement which generates a current whose temperature coefficient is only equal to zero at one specific temperature, steps are taken, in accordance with the invention, to render the generated current independent of the temperature over a wide temperature range by compensation of the disturbing factor in the relationship between the generated current and the temperature.
51 citations
TL;DR: In this article, the density and electrical conductivity of expanded liquid Hg in the temperature and pressure range up to 1500°C and up to 2200 bar have been investigated.
Abstract: Simultaneous measurements of the density and electrical conductivity have been carried out for expanded liquid Hg in the temperature and pressure range up to 1500°C and up to 2200 bar. At densities below 10 g/cm 3 the temperature coefficient of the conductivity at constant volume increases appreciably with decreasing density. Anomalous behaviours are found in the thermodynamic properties such as equation-of-state and isothermal compressibility when the metallic Hg is transformed to a nonmetallic state. Structural changes in the metal-nonmetal transition range are discussed in connection with the observed thermodynamic properties.
TL;DR: In this article, the dielectric properties of amorphous Nd2O3 films prepared by vacuum evaporation using an electron beam were investigated as functions of film thickness (700-3000 A), temperature (78-400 K), and frequency (0.040-100 kHz) for various substrate temperatures.
TL;DR: The dielectric constants of two lithium ternary chalcogenides, LiInSe2 and LiGaSe2, were obtained to be 8.45 and 8.75, respectively, by capacitance measurements at room temperature as mentioned in this paper.
Abstract: The dielectric constants of two lithium ternary chalcogenides, LiInSe2 and LiGaSe2, are obtained to be 8.45 and 8.75, respectively, by capacitance measurements at room temperature. The temperature dependence of dielectric constants of both crystals show linear increase with temperature over the range 77–300 K. The temperature coefficients for LiInSe2 and LiGaSe2 are 2.90×10−4 and 3.80×10−4 K−1, respectively. The bond parameters of LiInSe2 and LiGaSe2 are obtained using the Phillips‐Vechten’s and Levine’s dielectric model. The bond characteristics are discussed within the concepts of ionicity and transverse effective charge.
IBM1
TL;DR: In this article, a series of digital simulations indicates that an accurate measurement of the surface-tension temperature coefficient is important to the understanding of melt flow in Czochralski growth of silicon.
TL;DR: In this article, the structural relaxation of amorphous metal alloys with different Mo content was studied through electrical resistivity measurements between the room temperature and the glass transition temperature Tg, and a simple relation between the variation of α after annealing, and the reduction of the alloys free volume was derived and discussed.
Abstract: The structural relaxation of Fe‐Ni‐Mo‐B alloys with different Mo content is studied through electrical resistivity measurements between the room temperature and the glass transition temperature Tg. The observed behavior of the resistivity during isothermal annealing treatments gives evidence for the presence of competing processes of compositional and topological short‐range ordering, whose nature and role are discussed. The variation of the temperature coefficient of resistivity, α, observed after annealing of ribbons, is related to the variation of the degree of topological short‐range order, and interpreted on the basis of the theories describing the electrical resistivity and the structural relaxation of amorphous metals. A simple relation between the variation of α after annealing, and the reduction of the alloys’s free volume, is derived and discussed.
TL;DR: In this article, the Stockmayer-Fixman extrapolation was applied to the data: it yields the unperturbed dimensions K0 of the chain, which indicates that the polymer molecules are expanded in this solvent as the temperature is raised.
01 Jan 1982
TL;DR: In this paper, the temperature dependence of CH radicals with NO, O2, CO2 and CO2 was studied in the range from 297 to 676K in 100 torr of Ar buffer gas using a two-laser, photolysis/probe technique.
Abstract: The temperature dependence of the reactions of CH radicals with NO, O2, CO2 and CO was studied in the range from 297 to 676K in 100 torr of Ar buffer gas using a two-laser, photolysis/probe technique. The CH radicals were generated by the multiphoton dissociation of CHBr3 at 266 nm and detected by LIF at 429.8 nm. The reactions of CH with No and O2 show very little temperature dependence with k=(1.9±0.3)×10−10 and k=(5.4 ±1.0)×10−11 cm3 molecule−1 s−1, respectively. The rate of reaction of CH with CO2 increases with increasing temperature and can be described in the temperature range studied by k =(5.7±0.9)×10−12exp[(-345±53)/T] cm3 molecule−1s−1. The reaction of CH with CO has a negative temperature coefficient and was also found to be pressure-dependent. The rate constant for the reaction in 100 torr of Ar buffer gas is k=(4.6±1.0) ×10−13 exp [(861±101)/T] cm3 molecule−1 s−1 in the temperature range studied. The rate constant at room temperature increases by a factor of 3 over the range of buffer gas pressure from 50 to 640 torr. These observations are explained in terms of a long-lived complex, the HC2O adduct.
TL;DR: In this paper, the Avrami exponent is an integral number, 3, and is independent of temperature and molecular weight, and the level of crystallinity is dependent on molecular weight.
Patent•
27 May 1982TL;DR: Improved thin film resistors and electrical devices and circuits with thin-film resistors are fabricated utilizing a chromium, silicon, and nitrogen compound formed preferably by reactive sputtering of chromium and silicon in a nitrogen bearing atmosphere.
Abstract: Improved thin film resistors and electrical devices and circuits with thin film resistors are fabricated utilizing a chromium, silicon, and nitrogen compound formed preferably by rf reactive sputtering of chromium and silicon in a nitrogen bearing atmosphere. An annealing step is used to produce time-stable resistance values and in combination with variations in the partial pressure of nitrogen during sputter deposition to control the temperature coefficient of resistivity to have positive, negative or zero values.
TL;DR: In this article, the electrical resistivity ρ and its temperature coefficient α have been measured on amorphous ribbons prepared with different quenching rates and interpreted in terms of a theory based on the Ziman approach to the resistivity of metallic glasses.
TL;DR: In this article, the electrical resistance of metallic glasses was measured as a function of temperature between 1.5 and 300K under pressures of up to 12 GPa (120 kbar).
Abstract: The electrical resistance of metallic glasses was measured as a function of temperature between 1.5 and 300K under pressures of up to 12 GPa (120 kbar). Depending on the system, the resistivity is either found to increase (Mg70Zn30) or to decrease (Cu57Zr43, Ti50Be40Zr10). This behaviour is in contrast to the negative temperature coefficient of resistivity which all the amorphous alloys considered here exhibit. The results are compared with theoretical predictions.
TL;DR: In this article, the authors investigated the effect of the structural phase transition on the band edge structure of Pb 1-x Ge x Te by means of the interband absorption and the Shubnikov-de Haas (SdH) effect.
Abstract: The band edge structure modification of Pb 1- x Ge x Te due to the structural phase transition has been investigated by means of the interband absorption and the Shubnikov-de Haas (SdH) effect. Below the phase transition temperautre ( T c ) the band gap determined by the optical absorption increases with lowering temperatures or at least its temperature coefficient changes. From the SdH effect below T c , we obtained the information of the carrier redistribution among the conduction (or valence) bands caused by the phase transition. These results can be explained only when we take into account the effects of relative sublattice displacement and the homogeneous strain at the same time.
01 Jan 1982
TL;DR: In this article, the growth and characterization of ZnO films having C-axis oriented 40° to the substrate normal was reported, which are of significant importance for shear wave generation for bulk wave delay lines and resonators.
Abstract: This paper reports on the growth and characterization of ZnO films having C-axis oriented 40° to the substrate normal. These films are of significant i nterest for shear wave generation for bulk wave delay lines and resonators. The films were grown on Si wafers or membranes under low pressure and high growth rate conditions in a reactive dc planar magnetron sputtering system having an auxiliary anode structure. resonators were fabricated and used for film evaluation. A ZnO/Si composite resonator exhibited a Q of approximately 4600 at 293 MHz fundamental resonance. The effective coup ing c oefficient of the film alone was found to be 17% (k2=.029) using an edge-only supported ZnO pla e resonator. The temperature coefficient of the ZnO resonator was found to be -36 ppm/CO and -20.5 ppm/CO for the composite structure. Shear wave
TL;DR: In this paper, an exact numerical model of the semiconductor transport equations is used to calculate the output parameters of the cell taking into account temperature effect on the material parameters of a p-n junction solar cell.
TL;DR: In this paper, the material properties are stabilized by modification with Mn. The required positive temperature coefficient of the frequency constant is realized with the aid of elastic anomalies in the region of ferroelectric phase transitions.
Abstract: Piezoelectric ceramics are prepared for fabricating the electromechanical transducers used in the mechanical frequency filters that find application in long-haul communications systems. These ceramics have to satisfy specifications that can only be met by utilizing all the possibilities offered by the physical effects of the ferroelectric material. The material properties are stabilized by modification with Mn. The required positive temperature coefficient of the frequency constant is realized with the aid of elastic anomalies in the region of ferroelectric phase transitions. Complex additives sharply increase permittivity while keeping mechanical losses low. Through the careful coordination of additives for softening and stabilization it is possible to prepare stabilized ceramics with the typically high piezoelectric coupling coefficient of soft ceramics accompanied by a high mechanical quality factor and effective resistance to aging. Moreover, any sharp increase in mechanical losses due to a rise in te...
TL;DR: In this paper, the properties of the as-deposited amorphous (Ti+Si) films were found to be consistent with theories for disordered metal-metal alloys.
Abstract: Films of titanium silicide were deposited on oxidized silicon wafers by means of the coevaporation of titanium and silicon. The atomic concentration range 0?Si/Ti?4 was studied. The films were annealed in hydrogen ambient in the temperature range 300–1000 °C. For Si/Ti≊2, annealing between 800 and 900 °C results in the formation of TiSi2 with a resistivity as low as 15–25 μΩcm and a grain size of 200–500 A. In situ annealing in a transmission electron microscope and differential thermal analysis show that the crystallization of the silicide starts at 350 °C. The properties of the as‐deposited amorphous (Ti+Si) films were found to be consistent with theories for disordered metal‐metal alloys. The resistivity behavior (a low temperature coefficient, which is independent of temperature and composition) can be described in terms of Mooij’s rule. The crystallization temperature of 350 °C is in agreement with a model proposed by Buschow.
TL;DR: In this paper, the morphology and growth rates of poly(1,3-dioxolane) fractions were studied by polarized light microscopy and two different supermolecular structures, dependent on molecular weight and crystallization temperature have been found.
Patent•
20 Oct 1982TL;DR: In this article, a reference voltage generating circuit comprises a circuit (20) for generating a current having a positive temperature coefficient, an additional circuit (30) for synthesizing a current with a negative temperature coefficient and another circuit (Q7, Q13, R3) for converting the synthesized current into the reference voltage.
Abstract: A reference voltage generating circuit comprises a circuit (20) for generating a current having a positive temperature coefficient, a circuit (30) for generating a current having a negative temperature coefficient and a circuit (Q7, Q13, R3) for synthesizing both currents and converting the synthesized current into a reference voltage. The circuit (20) for generating a current having a positive temperature coefficient converts a difference voltage between respective base-emitter voltages of two transistors (Q2, Q3) included therein, both bases of which are connected to each other, into a current through a resistor (R2), while a negative feedback is applied by utilizing a current mirror (Q9˜Q13). The circuit (30) for generating a current having a negative temperature coefficient converts a voltage between a base and an emitter of a single transistor (Q1) into a current through a resistor (R1) while a negative feedback is applied by utilizing a current mirror (Q5˜Q7). The current having a positive temperature coefficient and the current having a negative temperature coefficient are synthesized to become a temperature compensated current which is converted into a reference voltage by a resistor (R3). Temperature coefficients of the resistors (R1, R2, R3) are set to be equal and thus are cancelled.
TL;DR: In this paper, a new positive temperature coefficient (PTC) resistor and its properties are described which utilizes the metal-insulator solid-state transition in (V,Cr) 2 0 3.
Abstract: A new positive temperature coefficient (PTC)resistor and its properties are described which utilizes the metal-insulator solid-state transition in (V,Cr) 2 0 3 . At a transition temperature of 80°C, for example, the specific resistivity of a ceramic body exhibits a · rapid increase to a value 100 times higher than that at 20°C, which is typically 1.5x 10-3 \Omega cm. Due to this low resistivity, thermistors with resistance values between at least 0.1 m \Omega and 0.1 \Omega can be manufactured which can carry rated currents substantially higher than 200 A or lower than 2 A, respectively. The construction of the new device is described, and typical properties and applications are illustrated.
01 Jan 1982
TL;DR: In this paper, the effect of different surface treatments, prior to polysilicon deposition, is investigated by comparing results obtained for a dip etch in hydrofluoric acid with those for an RCA clean.
Abstract: Silicon bipolar transistors have been made with arsenic-implanted or phosphorus-diffused polysilicon emitters. The effects of different surface treatments, prior to polysilicon deposition, are investigated by comparing results obtained for a dip etch in hydrofluoric acid with those for an RCA clean. Detailed electrical results are presented for these two types of device, including transistor characteristics as a function of temperature. Rutherford backscattering is used to provide the arsenic profiles in the polysilicon and single-crystal silicon. It is shown that the dip etch devices have gains three times higher than conventional transistors, and a comparable temperature coefficient of the current gain. In contrast, the RCA devices have gains which are seven to thirty-two times higher than conventional transistors and a temperature coefficient which is superior. These results are explained using theoretical models from the literature.