Showing papers by "Sun Yat-sen University published in 1992"
TL;DR: In this article, the emission parameters for Eu 3+ (Tb 3+ ) complexes with 1-indoleacetylacetone (HL 1), 3-indolabeled e.g., 3-influenced Eu-3+ and Eu 2+ diketones and the energy levels of excited triplet states for the three ligands were determined.
53 citations
TL;DR: In this paper, the authors used a combined treatment system, which includes an aquatic treatment pond withTypha latifolia Linn. (Typhaceae) as the dominant species and a stabilization pond, to treat the wastewater from a Pn/Zn mine at Shaoguan, Guangdong Province, China.
Abstract: This article describes the use of a combined treatment system, which includes an aquatic treatment pond withTypha latifolia Linn. (Typhaceae) as the dominant species and a stabilization pond, to treat the wastewater from a Pn/Zn mine at Shaoguan, Guangdong Province, China. In 1983, it was noted thatT. latifolia bloomed in areas affected by the wastewater emitted from the mine, hence a combined purification system was subsequently built. The influent contained high levels of total suspended solids (4635 mg/liter), chemical oxygen demand (14.5 mg/liter) as well as Pb (1.6 mg/liter) and Zn (1.9 mg/liter). The results of the effluent after treatment showed that the total suspended solids, chemical oxygen demand, Pb, and Zn had been reduced by 99%, 55%, 95%, and 80% respectively. The results of plant tissue analysis indicled thatT. latifolia assimilated significant amounts of Pb and Zn, especially in the root portion. During 1986 several species of algae and fish were present in the pond, usually with a higher density in areas containing lower metal concentrations in the water.
38 citations
TL;DR: The increase in routine oxygen consumption associated with dark periods and feeding emphasize the importance of sufficient dissolved oxygen in production ponds during the night and when the shrimps are being fed, and insufficient dissolved oxygen during these periods would improve production.
35 citations
TL;DR: In this paper, it was shown that with an increase of reaction time or concentration of agent, the conversion of nitrile groups in PAN increases rapidly at first, and then more slowly.
33 citations
TL;DR: In this article, a comparison between the states of a 3-valence-electron system and a 3vence-neutron system was made, and it was shown that the symmetry governing the particular quantum system plays an essential role.
Abstract: A comparison has been made between the states of a 3-valence-electron system and a 3-valence-neutron system. The fermions are supposed to move in a sphere. The structures and internal motions of the head-states (the lowest of a given2S+1Lπ) of these systems havingL=0,S=1/2 and 3/2, and even and odd parity have been investigated. We have found that the symmetry governing the particular quantum system plays an essential role. In particular, all the nodal surfaces in the head-states originate from symmetry but not from dynamics. Consequently, the head-states of different dynamic systems have similar structures and similar internal motions.
31 citations
TL;DR: In this paper, a differential-pulse polarography (DPP) method was used to determine the amount of ethanol in a sample of a single malt with a specified detection limit of 0.02% or 0.2 mg.
Abstract: Ethanol, after in situ derivatization to ethyl dithiocarbonate under phase-transfer catalysis, was determined in aqueous solution by differential-pulse polarography. A supporting electrolyte of NH4Cl—KH2PO4—NaOH containing eosin was found to be essential in this determination. For the microdetermination of ethanol, this method was proved to be precise, and the detectionlimit was 0.02% or 0.02 mg (absolute amount of ethanol). The viability of the proposed method for beer analysis has also been established.
23 citations
TL;DR: Four new sesquiterpenes, angulatueoids A-D, have been isolated from the seeds of Celastrus angulatus by spectroscopic means, including an X-ray diffraction analysis of angul atueoid A.
23 citations
TL;DR: Five new 20,24-bishomoscalarane sesterterpenes, phyllactones A and B, are reported from the sponge Phyllospongia foliascens collected in the waters of the Nansha Islands in the South China Sea.
Abstract: Five new 20,24-bishomoscalarane sesterterpenes, phyllactones A [1], B [2], C [3], D [4], and E [5], are reported from the sponge Phyllospongia foliascens collected in the waters of the Nansha Islands in the South China Sea. Structural elucidation of these compounds is based on spectral data and chemical conversions. Phyllactones A and B show moderate cytotoxicity against KB cells (IC50 20 micrograms/ml).
21 citations
TL;DR: In this paper, a new solvent, 4-chlorophenol, has been used to dissolve poly(ether ether ketone), PEEK, over an extended concentration range, and some properties of the solution were measured and possible effects of the solvent on PEEK were investigated.
21 citations
TL;DR: In this paper, a variational technique for determining the parameters of the three different approximate solutions for the fundamental mode field distribution of Ti:LiNbO/sub 3/ optical waveguides by using variational techniques is presented.
Abstract: Methods for determining the parameters of the three different approximate solutions for the fundamental mode field distribution of Ti:LiNbO/sub 3/ optical waveguides by using the variational technique are presented. This analysis gives closer approximation not only to the field distribution, but also to the propagation constant. Comparison with the exact results for the exponential index distribution in depth shows that these trial functions are closer to the real solution. It is also shown that these solutions are as accurate as the effective index method for Ti:LiNbO/sub 3/ strip waveguides. The analysis provides an approach for comparing and assessing these solutions. >
19 citations
25 May 1992
TL;DR: In this paper, a new method for optimizing the output of a solar cell array is presented Several curves printed under different solar radiation levels and temperatures are given out It is confirmed by an experimental setup that introducing this output control method, compared with using the traditional charging method, can obtain notably more power from the same solar cell arrays.
Abstract: A new method for optimizing the output of a solar cell array is presented Several curves printed under different solar radiation levels and temperatures is given out It is confirmed by an experimental setup that introducing this output control method, compared with using the traditional charging method, can obtain notably more power from the same solar cell array >
TL;DR: In this article, the phase morphologies, melting and crystallization behaviors of poly(ether ether ketone) (PEEK) with a thermotropic liquid crystal copolyester (LCP-111), obtained by solution precipitation, were investigated by optical microscopy and differential scanning calorimetry.
Abstract: Blends of poly(ether ether ketone) (PEEK) with a thermotropic liquid crystal copolyester (LCP-111), obtained by solution precipitation, were investigated by optical microscopy and differential scanning calorimetry. The as-precipitated blends underwent phase segregation on heating, as being evident by the microscopy observation. The phase morphologies, melting and crystallization behaviors of the blends were found to be affected by the LCP composition, showing smaller crystal size, slight depression of Tm and higher degree of crystallinity with increasing LCP content. When isothermally crystallized from the melt, a maximum overall rate of crystallization was found for the blend containing about 20 wt% of LCP. The results were discussed in terms of competition between the nucleation and dilution effects of LCP on the crystallization of PEEK.
TL;DR: Preparations of exochitinase which were electrophoretically homogeneous have been prepared from seeds of Zea mays and Coix lachryma-jobi by extraction, ammonium sulphate fractionation and gel filtration, and the purified preparations did not exhibit lysozyme activity.
TL;DR: In this paper, the interaction between narrow wave beam-type high frequency gravitational radiation of crystal space array and electromagnetic fields was discussed and the perturbed solutions have been obtained, and it was shown that this gravitational wave beam with optimal radiation direction is purely + type polarized in TT coordinate system, and can make electromagnetic wave which has the same frequency, to generate perturbed effects of frequency doubling, make static electromagnetic fields to generate cumulative effect linear in time.
Abstract: Starting with the Einstein-Maxwell equations of weak gravitational field, we discussed the interaction between narrow wave beam-type high frequency gravitational radiation of crystal space array and electromagnetic fields. The perturbed solutions have been obtained. By our calculation, it is shown that this gravitational wave beam with optimal radiation direction is purely + type polarized in TT coordinate system, and it can make electromagnetic wave, which has the same frequency, to generate perturbed effects of frequency doubling, make static electromagnetic fields to generate cumulative effect linear in time. For the gravitational radiation wave beam with an arbitrary direction, it is also purely+type polarized in the plane perpendicular to the gravitational wave vector. Under the condition of high frequency radiation and laboratory's typical size, difference between TT coordinate and Fermi coordinate systems can be neglected.
Journal Article•
TL;DR: There is a need for additional studies examining the specific topographical relationship between H. pylori, the histology, and gastroduodenal disease.
TL;DR: The crystallization kinetics of blends of poly(aryl ether ether ketone) (PEEK) and thermotropic liquid-crystalline copolyesters have been studied by differential scanning calorimetry and optical microscopy.
TL;DR: In this article, a model where three electrons move in the surface of a sphere is used to simulate the 2S e states of three (valuence) electron atoms with all three electrons at the same shell.
Abstract: A model where three electrons move in the surface of a sphere is used to simulate the2S e states of three (valuence) electron atoms with all three electrons at the same shell. A non-co-plane structure and a number of co-plane structures (triangle, straigh rod, and sharp wedge) together with associated modes of motions have been found. It is found that the symmetry has decisive effects on the structure of quantum states. Besides, in the case that the number of the spin-up electrons does not equal to that of the spin-down electrons, the up and down electrons may play different role in constituting the internal motions.
TL;DR: In this article, a modified version of the KBM method was used to generate limit cycle phase portrait, amplitude, period and to indicate stability of the limit cycle, which can be used to indicate the stability of a limit cycle.
Abstract: The problem of periodic solutions of nonlinear autonomous systems with many degrees of freedom is considered. This is made possible by the development of a modified version of the KBM method[1]. The method can be used to generate limit cycle phase portrait, amplitude, period and to indicate stability of the limit cycle.
TL;DR: The root-bark of Tripterygium forrestii afforded wilfordine, wilforine and a new sesquiterpene alkaloid, named forrestine, shown to be a benzoyleuonymine by comparison of its 1 H NMR data with those of known compounds.
TL;DR: In this article, a nonlinear time transformation method is presented for the analysis of strong nonlinear oscillation systems, which can be used to study the limit cycle behavior of the autonomous systems and to analyze the forced vibration of a strong non-linear system.
Abstract: In this paper, a nonlinear time transformation method is presented for the analysis of strong nonlinear oscillation systems. This method can be used to study the limit cycle behavior of the autonomous systems and to analyze the forced vibration of a strong nonlinear system.
TL;DR: In this article, the spherulitic morphology of poly(ether-ether-ketone) has been studied by using polarizing light microscopy, IR and differential scanning calorimetry.
Abstract: The spherulitic morphology of poly(ether-ether-ketone)1 (PEEK) has been studied by using polarizing light microscopy, IR and differential scanning calorimetry. It has been found that in distinct cases the spherulites of PEEK show radiated or banded morphology, which can change from one to another upon thermal treatment. The process was found to be reversible and also affected by the film thickness.
TL;DR: Two polyhydroxylated steroids have been isolated from the South China Sea soft coral Sinularia microclavata, and their structures were established as 24-methylenecholestane-1 alpha, 3 beta,5 alpha,6 beta-tetrol and 1 alpha,3 beta, 5 alpha-trihydroxy-24- methylene cholestan-6-one.
TL;DR: In this paper, a Fourier transform dielectric spectrometer is described, which leads to simplifying the process of solving spectrum and to save the memory capacity for data, and it is shown that the free and random relaxation will appear under different conditions in the time range of 10 6 to 10 -4 seconds.
Abstract: A method of Fourier transform dielectric spectrometer is described, it leads to simplifying the process of solving spectrum and to save the memory capacity for data. Using this method, it is shown that for the same dielectric sample the free and random relaxation will appear under different condition in the time range of 10 6 to 10 -4 seconds, that was predicted by the phe-nomenoiogical theory. The relaxation times are related to the resistance R of the measurement circuit joinning the two electrodes of the sample.. Large value of R leads to a relaxation time of open circuit, and small ones lead to the limit of short circuit; the relaxation time of open ciecuit may be as large as 10 6 times of the short circuit one. The variation in frequancy domain spectrums of complex dielectric constant is given from open to short circuit cases.
TL;DR: The recent developments and achievements of the application of Mossbauer spectroscopy to archaeological problems are reviewed in this paper, where the relevances of the use of MOS in studies of provenance, manufacturing technology and age dating of ancient pottery, as well as the ancient bronzes are discussed.
Abstract: The recent developments and achievements of the application of Mossbauer spectroscopy to archaeological problems are reviewed. The relevances of Mossbauer spectroscopy in studies of provenance, manufacturing technology and age dating of ancient pottery, as well as the ancient bronzes are discussed.
TL;DR: It is proved that Fork-prefix andk-suffix codes withk≥2,k-infix, k-outfix, p- infix, right semaphore codes and left semaphor codes, etc., are group codes if and only if they are uniform codes.
Abstract: In this paper, we study the following problem: Which characteristics does a codeC possess when the syntactic monoidsyn(C *) of the star closureC * ofC is a group? For a codeC, if the syntactic monoidsyn(C *) is a group, then we callC a group code. This definition of a group code is different from the one in [1] (see [1], 46–47). Schutzenberger had characterized the structure of finite group codes and had proved thatC is a finite group code if and only ifC is a full uniform code (see [5], [8]). Fork-prefix andk-suffix codes withk≥2,k-infix,k-outfix,p-infix,s-infix, right semaphore codes and left semaphore codes, etc., we obtain similar results. It is proved that the above mentioned codes are group codes if and only if they are uniform codes.
TL;DR: In this paper, the approximate quantum numbers of doubly excited helium states have been evaluated and a strong mixing of the symmetrized and antisymmetric components has been found in the {ital A}=0 states.
Abstract: The approximate quantum numbers {ital A} and {ital T} in the ({ital K},{ital T}){sup {ital A}} classification scheme of doubly excited helium states have been evaluated. A strong mixing of the symmetrized and antisymmetrized components has been found in the {ital A}=0 states. A direct verification supporting rotorlike structures has also been found.