Showing papers by "Chinese Academy of Sciences published in 1981"
TL;DR: In this article, the authors compared the horizontal and vertical circulation patterns over the Qinghai-Xizang (Tibet) plateau during summer, derived from meteorological observations, with results from rotating annulus experiments.
Abstract: Horizontal and vertical circulation patterns over the Qinghai-Xizang (Tibet) plateau during summer, derived from meteorological observations, are compared with results from rotating annulus experiments. There are several striking features during the season when the plateau acts as a huge elevated heat source: 1) a heat low dominates the planetary boundary layer over the plateau; 2) this heat low is broken up into several cells, giving rise to shear-line development; 3) surrounding the heat low is an anticyclonic belt; 4) the northern and southern portions of this belt approach each other as one proceeds into the upper troposphere and finally merge into a large anticyclone over the plateau; and 5) significant circulation cells appear in meridional and zonal cross sections, attesting to the strong influence of the plateau on the general circulation of the atmosphere.
171 citations
TL;DR: In this article, a study of the problem of a penny-shaped crack in an infinite body of power-law material subject to general remote axisymmetric stressing conditions is carried out.
Abstract: A study is carried out of the problem of a penny-shaped crack in an infinite body of power-law material subject to general remote axisymmetric stressing conditions. The plane strain version of the problem is also examined. The material is incompressible and is characterized by small strain deformation theory with a pure power relation between stress and strain. The solutions presented also apply to power-law creeping materials and to a class of strain-rate sensitive hardening materials. Both numerical and analytical procedures are employed to obtain the main results. A perturbation solution obtained by expanding about the trivial state in which the stress is everywhere parallel to the crack leads to simple formulas which are highly accurate even when the remote stress is perpendicular to the crack.
146 citations
TL;DR: The elemental composition of duplicate aerosol samples from north China, collected in particle size fractions by eight-stage cascade impactors on the Great Wall, near Beijing, is reported for 21 elements measured by particle induced X-ray emission analysis as discussed by the authors.
86 citations
TL;DR: In this paper, a short summary of work being performed at the Lanzhou Institute of Plateau Atmospheric Physics of the Academia Sinica is presented, followed by a description of the main features of annual and diurnal cycles in pressure and circulation patterns.
Abstract: The Qinghai-Xizang (Tibet) Plateau has a profound influence on atmospheric circulation patterns on all time and space scales. This report constitutes a short summary of work being performed at the Lanzhou Institute of Plateau Atmospheric Physics of the Academia Sinica. A short discussion of the climatic characteristics of the plateau is followed by a description of the main features of annual and diurnal cycles in pressure and circulation patterns.
60 citations
TL;DR: The phenomenon of lattice relaxation, namely, that the atomic configuration surrounding a localized center in solids changes with its change of electronic state, leads to various forms of multiphon as discussed by the authors.
Abstract: The phenomenon of lattice relaxation, namely, that the atomic configuration surrounding a localized centre in solids changes with its change of electronic state, leads to various forms of multiphon...
49 citations
TL;DR: Wang et al. as mentioned in this paper established a mathematical model to simulate the vertical one-dimensional flow processes in unsaturated zone, based on the basic equation of soil water movement and the actual layer structure of coniferous forest brown soil on northern slope of Changbai Mountains.
Abstract: This paper established a mathematical model to simulate the vertical one-dimensional flow processes in unsaturated zone, based on the basic equation of soil water movement and the actual layer structure of coniferous forest brown soil on northern slope of Changbai Mountains. The numerical discrete equations of this model were derived, and the procedure for the numerical simulation of the model was programmed. This model was validated with numerical simulation, and the simulation values were consistent well with the measurements.
44 citations
TL;DR: Two graphical rules are presented to deal with the non-steady state enzyme catalysed reaction systems and are useful in order for avoiding the omission of terms during calculations, especially, for complicated mechanisms.
42 citations
TL;DR: In this paper, it was shown that due to the combined relativistic and loss cone effects, the cutoff frequency can be lower than the electron cyclotron frequency, a result in contrast with that obtained with the usual cold plasma approximation.
Abstract: Two cases are investigated. In the first case the electron distribution is assumed to have a loss‐cone feature. It is found that the plasma can amplify electromagnetic waves near the electron cyclotron frequency, as expected. However, the growth rate is significantly larger than that used in an approximate calculation in which a slightly different physical model was considered. The present discussion is restricted to the fast extraordinary‐ mode radiation. One of the important conclusions is that, due to the combined relativistic and loss‐cone effects, the cutoff frequency can be lower than the electron cyclotron frequency, a result in contrast with that obtained with the usual ’’cold plasma’’ approximation. In the second case a drift motion along the ambient magnetic field is studied. It is found that the cyclotron damping can occur under certain conditions.
39 citations
TL;DR: In this article, a quasi-linear theory is used to study the saturation level of the auroral kilometric radiation, which is based on the assumption that the emission is due to a cyclotron maser instability.
Abstract: A quasi-linear theory is used to study the saturation level of the auroral kilometric radiation. The investigation is based on the assumption that the emission is due to a cyclotron maser instability as suggested by Wu and Lee and Lee et al. The thermodynamic bound on the radiation energy is also estimated separately. The energy-conversion efficiency of the radiation process is discussed. The results are consistent with observations.
35 citations
TL;DR: The schematic method, when applied to enzyme kinetics, can establish some direct relations between the calculation rules and the graphs expressing the enzyme-catalysed mechanisms.
29 citations
TL;DR: In this paper, an ellipsoidal model was used to represent the location of the dayside magnetopause and to study the influences of the interplanetary magnetic field and thermal pressure on its location.
Abstract: An ellipsoidal model, in which the size of an ellipsoid of revolution with a constant eccentricity is inversely proportional to the sixth root of the stream pressure of the solar wind, is used to represent the location of the dayside magnetopause and to study the influences of the interplanetary magnetic field and thermal pressure on its location. The effects of the IMF and thermal pressure on the location of the magnetopause are calculated analytically by using the Chapman-Ferraro theory. The changes in magnetopause size, shape and orientation caused by including the thermal pressure are inversely proportional to the square of the sonic Mach number of the solar wind and are sufficient to explain the observed slight departure of the magnetotail from the expected aberration due to the earth's orbital motion. The results suggest that little angular momentum is being carried away from the sun by the solar wind.
TL;DR: In this article, the effects of an external field on the isotropic-nematic transition in liquid-crystalline substances were studied using the "orientationally averaged pair correlations" approximation.
Abstract: We study the effects of an external field on the isotropic-nematic transition in liquid-crystalline substances. The theoretical technique employed is called the "orientationally averaged pair correlations" approximation. It takes into detailed account spatial correlations between the molecules while treating orientational order in a mean-field-like manner. The results obtained for MBBA ($4\ensuremath{-}\mathrm{m}\mathrm{e}\mathrm{t}\mathrm{h}\mathrm{o}\mathrm{x}\mathrm{y}\mathrm{b}\mathrm{e}\mathrm{n}\mathrm{z}\mathrm{y}\mathrm{l}\mathrm{i}\mathrm{d}\mathrm{e}\mathrm{n}\mathrm{e}\ensuremath{-}4\ensuremath{'}\ensuremath{-}n\ensuremath{-}\mathrm{b}\mathrm{u}\mathrm{t}\mathrm{y}\mathrm{l}\mathrm{a}\mathrm{n}\mathrm{i}\mathrm{l}\mathrm{i}\mathrm{n}\mathrm{e}$) are compared to those of the Maier-Saupe theory and the Landau-de Gennes theory. We determine the paranematic-nematic coexistence curve, the temperature-external field phase diagram, the Cotton-Mouton coefficient, the maximum supercooling temperature, critical exponents, and the relation between the transition temperature and the electric field in laser-induced isotropic-nematic transitions. These results are compared to experimental data. Their implications are discussed.
TL;DR: The results calculated with the finite elements method show that the reaction limits will not decrease substantially if van der Waal's forces and a reasonable flexibility during such a juxtaposition are taken into account.
TL;DR: From Solidago decurrens several new benzyl benzoates and two cinnamyl angelates were variously isolated from stems, flower and root as discussed by the authors, and they were used in the extraction of benzyl-benzoates.
TL;DR: In this paper, the impacts on the utilisation of biogas from the aspects of technology, policy, institution, training and education are discussed, and the impacts of these aspects on the performance of digesters are discussed.
TL;DR: The synthesis of DHI from DOI and glycylphenylalanine through the catalytic action of trypsin is reported, which showed insulin activity of 7.5 IU mg−1 in vivo and could be obtained in crystalline form.
Abstract: The semisynthesis of deshexapeptide insulin (DHI) from desoctapeptide insulin (DOI) reported earlier1 showed that DHI was biologically active. However, the product was not quite homogeneous, mainly due to the esterification side reaction and the following saponification2. Recently, the catalytic action of trypsin was successfully used in the preparation of human insulin from porcine insulin3. It was also used in the preparation of insulin analogues with substitutions of B24 or B25 phenylalanine by leucine4,5. Here, we report the synthesis of DHI from DOI and glycylphenylalanine through the catalytic action of trypsin. The product, purified by gel filtration and DEAE-Sephadex ion-exchange chromatography, showed insulin activity of 7.5 IU mg−1 in vivo and could be obtained in crystalline form.
TL;DR: In this paper, a model is developed which takes into account the weight of the sphere and the static resistance of the medium into which penetration occurs, to explain the critical impact angle depends on the impinging velocity.
Abstract: It has been observed experimentally that when a sphere ricochets off water or sand the critical impact angle depends on the impinging velocity.To explain this, a model is developed which takes into account the weight of the sphere and the static resistance of the medium into which penetration occurs. The proposed model can also treat processes in which the angle of impact is large and where the velocity of the sphere undergoes considerable change. Projectile trajectories which have been calculated for various conditions are presented and discussed. Numerical results for steel, aluminium alloy, and lead spheres are in good agreement with such experimental results as are available.
TL;DR: In this article, the authors reported accurate values for the oscillator strength of potassium, and possible resolution of some outstanding discrepancies concerning oscillator strengths and photoionization cross sections of this atom.
Abstract: This Letter reports accurate values for the oscillator strength of potassium, and possible resolution of some outstanding discrepancies concerning the oscillator strengths and photoionization cross sections of this atom. Our results establish a value of (5.2 \ifmmode\pm\else\textpm\fi{} 0.5) \ifmmode\times\else\texttimes\fi{} ${10}^{\ensuremath{-}21}$ ${\mathrm{cm}}^{2}$ for the photoionization cross section at the series limit.
TL;DR: Homoharringtonine and hydroxycamptothecin can inhibit the cell proliferation of murine erythroleukemia cells (MELC) at low concentrations (ng/ml) whereas lycobetaine, cantharidin and oxalysine are less potent.
Abstract: The influence of homoharringtonine, hydroxycamptothecin and lycobetaine on the cell cycle progression of murine erythroleukemia cells was studied by using flow microfluorometry (FMF) technique and centrifugal elutriation to obtain specific fractions of the cell cycle. FMF histogram analysis showed that homoharringtonine could strongly arrest cells in the G1 phase of the immediate cell cycle. This effect was more pronounced and persisted longer with G1 cells than with S or G2 cells. Hydroxycamptothecin mainly delayed the progression of S cells of the subsequent cell cycle (daughter cells). Lycobetaine caused a marked accumulation of G2 cells. These 3 compounds possess a relatively specific action on cell progression through the cell cycle. Homoharringtonine and hydroxycamptothecin can inhibit the cell proliferation of murine erythroleukemia cells (MELC) at low concentrations (mg/ml) whereas lycobetaine, cantharidin and oxalysine are less potent. Among them only hydroxycamptothecin had a weak activity to induce MELC differentiation. These results may provide some basic knowledge for designing new protocols of the combination treatment of neoplastic diseases.
TL;DR: In this paper, the stress-strain relationship of chlorotrifluoroethylene and ethylene (abbr. as F-30) has been determined, and the dose of gelation of crosslinked F30 has been calculated.
TL;DR: In this article, the dependence of T/sub c/ on sputtering conditions, chemical composition, and phase structure for Nb-Ge films has been studied, and it was found that the dependence varied with composition, but was not dependent on exact stoichiometry of the film.
Abstract: The dependence of T/sub c/ on sputtering conditions, chemical composition, and phase structure for Nb--Ge films has been studied. It was found that T/sub c/ varied with composition, but was not dependent on exact stoichiometry of the film; the Nb/Ge ratio was <3 for very high T/sub c/approx.23 K films and approx.4 for films with T/sub c/approx.20 K. X-ray results showed that the films with T/sub c/approx.23 K contained a certain amount of tetragonal Nb/sub 5/Ge/sub 3/ with a lattice parameter of A15 phase approx.5.14 A. The depth profile of very high T/sub c/ films showed no increase of oxygen concentration at the film--substrate interface; no correlation of high T/sub c/ and impurities was found.
29 Jun 1981
TL;DR: This paper discusses a new algorithm for searching the shortest path in VLSIs by propagating wave fronts in four quadrants, which may be more advisable than Lee's algorithm for application to multi-layer wiring.
Abstract: This paper discusses a new algorithm for searching the shortest path in VLSIs by propagating wave fronts in four quadrants. The algorithm has been experimentally programmed in FORTRAN IV on a Hitac M-200H computer. The main advantages of this algorithm are: 1. When there is a shortest path between two points, it can always be found by this algorithm; 2. In this algorithm, searching waves are divided into four quadrants. In each quadrant, waves advance or trace-back independently, according to their own rules. Therefore, in the algorithm only the current waves and the next set of waves need to be remembered, irrespective of their history. Thus much less memory (about 1/10~1/100) is required than for Lee's algorithm [1] 3. During searching for a shortest path in this algorithm, only segments currently defined need to be investigated. This greatly cuts down operation time, when compared to for Lee's algorithm; 4. This algorithm may be more advisable than Lee's algorithm for application to multi-layer wiring.
TL;DR: In this paper, the authors discuss the problem of weighted simultaneous Chebyshev approximation to functions f1,fm ϵ C(X) (1 ⩽ m⩽ ∞), i.e., minimizing the expression ∥{∑ m j = 1 λ j ¦f j − q¦ p } 1 p ∥∞, where λj > 0, ∑m j = √ m j, f j, p ⩾ 1, p √ p, m j
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TL;DR: In this paper, a scheme is developed that allows a chain of power stations discharging into the same river to operate their cooling systems such that the output of total electricity is maximized and water temperature standards are accomodated.
Abstract: In most industrialized countries, environmental standards exist which prescribe the maximum allowable man-made increase in water temperature of a river. Together with flowrate and weather conditions, these standards determine the rate at which waste heat may be discharged into a river at any moment. Power generating stations with variable cooling systems can adjust their heat discharge into the river in compliance with environmental standards and by doing so exert an influence on power generation capacity. In this paper, a scheme is developed that allows a chain of power stations discharging into the same river to operate their cooling systems such that the output of total electricity is maximized and water temperature standards are accomodated. The optimum balance between stations is determined through dynamic programming. From the results of a simulation model using historical data, simple decision rules for day-to-day operation are abstracted. These rules are based solely on the river flow rates at each power station.
TL;DR: A practical system was designed, constructed, and clinically tested to remove the gallstones that remained in the hepatic or common bile ducts after surgical operations and the system was found to be effective.
Abstract: We have used hydroelastic waves to remove small gallstones in hepatic and common bile ducts. These stones were shaken off by the action of progressive and reflected traveling waves. The mechanical properties of the bile ducts were measured and an analysis of the propagation of hydroelastic waves in the liver-bile ducts was made. A practical system was designed, constructed, and clinically tested to remove the gallstones that remained in the hepatic or common bile ducts after surgical operations. The system was found to be effective.
TL;DR: Not only can much computation work be saved but a semianalytic expression for the concentration distribution will be obtained, which is very useful for analysis and discussion of the kinetic characteristics of this kind of reaction system.
Abstract: A semianalytic method is presented for computing the concentration distribution in enzyme–substrate fast reaction systems. By means of this method, not only can much computation work be saved but a semianalytic expression for the concentration distribution will be obtained. This expression is very useful for analysis and discussion of the kinetic characteristics of this kind of reaction system.
TL;DR: Using the μ*-model and the Rothwarf-Taylor equations, a superconductor will oscillate between two nonequilibrium superconducting states with different energy gaps when quasiparticles are injected at the edge of the energy gap through the tunneling effect as mentioned in this paper.
Abstract: Using the μ*-model and the Rothwarf-Taylor equations, this paper predicts that a superconductor will oscillate between two nonequilibrium superconducting states with different energy gaps when quasiparticles are injected at the edge of the energy gap through the tunneling effect. The main sources of origin of this oscillation are the quasiparticle injection at the gap edge and the existance of recombination phonons with energy Ω = 2δ(n). Under certain nonequilibrium conditions, the recombination phonon system does not take part in Cooper pair-breaking processes and can further stimulate the quasiparticles to recombine into pairs. The uncertainty δNp of the number N
pof Cooper pairs has the same order of magnitude as N
pitself in such an oscillating superconductor, so that the phase ϕ of the wave function has a definite value. If superconducting weak coupling is formed between such two oscillating superconductors, this system should be described in the θ-representation.