Showing papers by "Chinese Academy of Sciences published in 1992"
Book•
01 Jan 1992TL;DR: A review of the properties of hydrogen in crystalline semiconductors is presented in this paper, together with the reactions of atomic hydrogen with shallow and deep level impurities that passivate their electrical activity.
Abstract: A review of the properties of hydrogen in crystalline semiconductors is presented. The equilibrium lattice positions of the various states of hydrogen are detailed, together with the reactions of atomic hydrogen with shallow and deep level impurities that passivate their electrical activity. Evidence for several charge states of mobile hydrogen provides a consistent picture for both the temperature dependence of its diffusivity and the chemical reactions with shallow level dopants. The electrical and optical characteristics of hydrogen-related defects in both elemental and compound semiconductors are discussed, along with the surface damage caused by hydrogen bombardment. The bonding configurations of hydrogen on semiconductor surfaces and the prevalence of its incorporation during many benign processing steps are reviewed. We conclude by identifying the most important areas for future effort.
530 citations
491 citations
TL;DR: A possible involvement of NO in the DA release process in rat striatum is suggested, which is a widespread mechanism for the regulation of cell function and communication.
Abstract: It is becoming apparent that the synthesis of nitric oxide (NO) from L-arginine not only explains endothelium-dependent vascular relaxation, but is a widespread mechanism for the regulation of cell function and communication. We examined the role of NO on the endogenous dopamine (DA) release from rat striatum. Nitroprusside, in the concentration range of 3-100 microM, induced a dose-dependent increase in the endogenous DA release from rat striatal slices. The maximal response was 330% over the baseline release. A higher concentration of nitroprusside (300 microM) produced an inhibitory effect on the spontaneous release of DA. L-Arginine (10 and 100 microM), a substrate in the NO-forming enzyme system, also produced an elevation of DA release. L-Arginine-induced DA release was attenuated by NG-monomethyl-L-arginine, an inhibitor of NO synthase. NADPH (1 microM), a cofactor of NO synthase, enhanced L-arginine-induced DA release. These results suggest a possible involvement of NO in the DA release process in rat striatum.
269 citations
TL;DR: A one-dimensional quantum waveguide theory for mesoscopic structures is proposed, and the boundary conditions of the wave functions at an intersection are given, and it is found that the oscillating current consists of a significant component of the second harmonic.
Abstract: A one-dimensional quantum waveguide theory for mesoscopic structures is proposed, and the boundary conditions of the wave functions at an intersection are given. The Aharonov-Bohm effect is quantitatively discussed with use of this theory, and the reflection, transmission amplitudes, etc., are given as functions of the magnetic flux, the arm lengths, and the wave vector. It is found that the oscillating current consists of a significant component of the second harmonic. This theory is also applied to investigate quantum-interference devices. The results on the Aharonov-Bohm effect and the quantum-interference devices are found to be in agreement with previous theoretical results.
207 citations
TL;DR: Results show that postsynaptic PKC is essentially involved in both the initial induction and the subsequent maintenance of LTP, contrary to current views on the subject.
Abstract: Previous studies on the effects of protein kinase C (PKC) inhibitors intracellularly introduced into the postsynaptic neuron on long-term potentiation (LTP) in the hippocampal CA1 region showed that given before the tetanic stimulation they only blocked the development of the maintenance phase of LTP and that given after the tetanus they did not affect the continued maintenance of established LTP. We now report different results in such experiments obtained by looking into the dose-effect relationship of the inhibitors given to the postsynaptic neuron and making use of a synergistic effect of two inhibitors given together. We used the following three PKC inhibitors: polymyxin B (PMB), PKC-(19-31), and H7. With the intracellular delivery of the inhibitor(s) beginning 30 min before the tetanus, PMB in adequate dosage or a combination of PMB and PKC-(19-31), each at a low dosage, could block the development of LTP completely including its initial induction phase. With the delivery beginning at the time of the tetanus, PKC-(19-31) or H7 slowly caused the established LTP to decline to the baseline; this decline was greatly accelerated when PMB and PKC-(19-31) or PMB and H7 were given together. PMB and PKC-(19-31) given together 75-90 min or even 3 h after the tetanus caused a decline of the maintained LTP similar to the decline observed when both inhibitors were given at the time of the tetanus. These results show that postsynaptic PKC is essentially involved in both the initial induction and the subsequent maintenance of LTP, contrary to current views on the subject.
156 citations
TL;DR: In this article, an orography-cold surge-albedo-temperature feedback mechanism is developed in explaining the harsher climate over East Asia during glacial time and is thought to be one of the major contributors in promoting glacial development on the globe.
138 citations
TL;DR: In this article, the crystal structure, superconductivity and magnetic properties of the title compounds have been investigated and the results revealed that with the concentration of Pr being constant, the transition temperatureTc of this system decreases with the increasing of La, or rather with an increasing of effective ionic radii of rare earth elements and disappears at aboutx=0.6.
Abstract: The crystal structure, superconductivity and magnetic properties of the title compounds have been investigated. The results revealed that with the concentration of Pr being constant, the transition temperatureTc of this system decreases with the increasing of La, or rather with the increasing of effective ionic radii of rare earth elements and the superconductivity disappears at aboutx=0.6. The coefficient of electron specific heat and the density statesN (0) which were infered from the magnetic measurements also decrease with the increasing of the effective radii. The relation between the radii of rare earth elements and hybridization is briefly discussed.
134 citations
University of Turin1, University of Perugia2, Indiana University3, Chinese Academy of Sciences4, University of Bologna5, Russian Academy of Sciences6, University of Florence7, State University of Campinas8, Brown University9, Massachusetts Institute of Technology10, University of Urbino11, Saitama University12, University of Houston13, Northeastern University14, Ashikaga Institute of Technology15, Okayama University16, Okayama University of Science17, CERN18
TL;DR: The Large Volume Detector (LVD) as discussed by the authors is a multipurpose detector consisting of a large volume of liquid scintillator interleaved with limited streamer tubes.
Abstract: The Large Volume Detector (LVD) in the Gran Sasso underground Laboratory is a multipurpose detector consisting of a large volume of liquid scintillator interleaved with limited streamer tubes. In this paper we discuss its power to study low-energy cosmic neutrinos. The results show that the first LVD tower (368 tons of liquid scintillator) is well suited to detect neutrinos from gravitational stellar collapses within all of our Galaxy over a wide range of burst duration (up to a few hundred seconds). No burst candidates have been observed in the first two months of data taking.
116 citations
TL;DR: In the presence of the protective polymer poly(N-vinyl-2-pyrrolidone)(PVP), PVP-protected palladium, gold bimetallic colloids were obtained by refluxing a CH3OH H2O (1:1 by volume) solution of palladium chloride and chloroauric acid.
95 citations
TL;DR: In this article, 10 new kaurane-type diterpene glycosides named suaviosides were isolated from the leaves of Rubus suavissimus and their structures were determined mainly on the basis of NMR spectral evidence.
94 citations
01 Jan 1992
TL;DR: A glucose oxidase (GOD) electrode with ferrocene (Fc) used as an electron transfer mediator has been described in this article, where Fc was modified on a glassy carbon (GC) electrode surface, and the enzyme was then immobilized on the Fc-Nafion film.
TL;DR: In this article, a two-dimensional decagonal quasicrystal (DQC) has been found in binary Al-Co alloys in the composition range Al11Co4 to Al10Co4 after slow solidification from the melt.
Abstract: A two-dimensional decagonal quasicrystal (DQC) has been found in binary Al-Co alloys in the composition range Al11Co4 to Al10Co4 after slow solidification from the melt. The crystalline phase found most frequently coexisting with this DQC is two new structure variants, oneC-centered and the other primitive, of the monoclinic layer compound Al13Co4. Theira andc parameters are roughly τ2 times (τ = (1 + √5)/2 = 1.6180…) larger than the corresponding ones in Al13Co4. Moreover, a new orthorhombic phase Al3Co or Al11Co4 (Pnmn, a = 1.25 nm,b = 0.81 nm, andc = 1.46 nm) has also been found. As shown by the characteristic electron diffraction patterns (EDPs), these crystalline phases can be considered as approximate structures of the DQC. The lattice relationship between these phases has been discussed.
TL;DR: Juvenile white sturgeon (Acipenser transmontanus) were fed different levels (0, 7, 14, 21, 28, 35) of dietary D-glucose for 8 weeks as mentioned in this paper.
TL;DR: The principal refractive indices and the thermal coefficients for a LiNbO(3) crystal doped with 5 mol.
Abstract: The principal refractive indices and the thermal coefficients for a LiNbO(3) crystal doped with 5 mol. % MgO have been measured by a minimum-deviation method for the wavelengths of 0.53975, 0.6328, 1.0795, and 1.3414, microm in the temperature range 20-154.5 degrees C. The constants of modified Sellmeier equations are all given in the described temperature range. The measured results were used to calculate the type I critical phase-matching angles for 1.0795- and 1.3414-microm second-harmonic generation at room temperature and the noncritical phase-matching temperature for 1.0795-microm second-harmonic generation for LiNbO(3) crystal doped with 5 mol. % MgO. The values obtained agree well with the experimental results.
TL;DR: In this article, a new photocatalyst, ZnFe2O4 spinel powder without any noble metal loading, was studied in a dispersion system irradiated with visible light and under different conditions.
TL;DR: In this paper, the relationship between mountain permafrost and climate is still relatively unknown and the implications of zonation (latitude, continentality), the various climatic parameters (MAAT; freezing and thawing indices; basal snow temperature, BTS; solar radiation; and surface heat balance) and climate change are outlined for mountain permaffrost.
Abstract: The relationship between mountain permafrost and climate is still relatively unknown. The implications of zonation (latitude, continentality), the various climatic parameters (MAAT; freezing and thawing indices; basal snow temperature, BTS; solar radiation; and surface heat balance) and climate change are outlined for mountain permafrost. Some research priorities are suggested.
TL;DR: In this paper, a spinel of composition LiMn2-xCrxO4.35 (x approximately 0.2-0.4), prepared at 350-370-degrees-C, has a defective structure of low-crystallinity and a high surface area and can be cycled at 1 mA/cm2 (approximately C/3) with a stabilized capacity of 0.13 Ah/g.
Journal Article•
TL;DR: The cytotoxicities of 2 derivatives of artemisinin B and 2 derivativesof artemisic acid (designated as Compound A, B, C, and D) were investigated, using trypan blue dye exclusion test and colony-forming units assay.
Abstract: The cytotoxicities of 2 derivatives of artemisinin B and 2 derivatives of artemisic acid (designated as Compound A, B, C, and D) were investigated, using trypan blue dye exclusion test and colony-forming units assay. At the concentration of 5 micrograms.ml-1, the inhibition rates of these 4 compounds against murine leukemia cell line P388 were > 85%. When tested against human hepatoma cell line SMMC-7721 at 25 micrograms.ml-1, the inhibition rates of Compound A, B, C, and D were found to be 92.3%, 96.9%, 84%, and 82.1%, respectively, and 27%, 8%, 37.8%, 1.7% against normal human embryonic lung cell line WI-38, respectively. These 4 compounds all showed an inhibition rate of 100% against human gastric cancer cell line SGC-7901 at 50 micrograms.ml-1.
TL;DR: In this article, the positions of metallic atoms in crystal of K2O have been determined from a single high-resolution electron microscope image and from the combination of the image and the electron diffraction pattern.
TL;DR: Disinhibition appeared and developed concurrently with surround inhibition at stimulus intensities between 3 and 30 cd/m2, being represented in the phasic or the tonic component of responses depending on the cell type recorded.
TL;DR: A new imidazolate bridged Cu 2+, Zn 2+ binuclear complex [(dtma) CuImZn (dtma)]ClO 4 · 2.5H 2 O taken as an active site model for Cu,Zn-SOD has been synthesized and its crystal structure has been determined as mentioned in this paper.
TL;DR: A Prussian Blue-modified glassy carbon electrode prepared by simple adsorption exhibited excellent electrocatalytic activity in the oxidation of hydrazine in acidic media.
TL;DR: In this article, the authors present an explicit complex variable representation for orthotropic materials and a solution to a dislocation interacting with a crack is presented in two self-contained Appendices.
TL;DR: In this article, a Penrose-tiling approximant of the Al-Mn decagonal quasicrystal was derived from the structure of two sets of Penrose type tiles.
Abstract: A new Al-Mn orthorhombic crystalline phase isostructural with Al60 Mn11 Ni4, Al20 Mn3 Cu2, and the T3 AlMnZn phase has been found in coexistence with the decagonal quasicrystal in a rapidly solidified Al-Mn alloy. From the structure of this Penrose-tiling approximant two sets of Penrose-type tiles were derived. A structural model of the Al-Mn decagonal quasicrystal based on these tiles was proposed. This model agrees well with the recent experimental X-ray structural determination of the Al-Mn decagonal quasicrystal.
TL;DR: In this article, the background values of trace elements were studied in the source area of the Yangtze River and the geochemical characteristics of trace element distributions and the factors influencing the natural contents of these elements were discussed.
TL;DR: In this article, a two-dimensional numerical model for simulation of the effects of mulches was developed, and the governing equations were solved by the finite element approach of Galerkin-type together with the Douglas-Dupout prediction-correction method.
TL;DR: In this article, a comparison of vector magnetograms obtained at three different stations showed a high degree of consistency in the morphology of both longitudinal and transverse fields, and the presence of cross-talk between longitudinal fields and transversal fields, Faraday rotation and signal saturation effects in the magnetograms.
Abstract: Joint vector magnetograph observations were carried out at Big Bear Solar Observatory (BBSO), Huairou Solar Observing Station (Huairou), and Mees Solar Observatory (MSO) in late September 1989. Comparisons of vector magnetograms obtained at the three stations show a high degree of consistency in the morphology of both longitudinal and transverse fields. Quantitative comparisons show the presence of noise, cross-talk between longitudinal field and transverse field, Faraday rotation and signal saturation effects in the magnetograms. We have tried to establish how the scatter in measurements from different instruments is apportioned between these sources of error.
TL;DR: In this paper, the effect of Cu on the anodic dissolution behavior of stainless steel in acidic 3.5% NaCl solution at 80°C was studied by electrochemical and AES techniques.
TL;DR: Four new steroid saponins, kingianosides A-D, were isolated from the rhizome of Polygonatum kingianum, together with two known steroid Saponins.