电网分析仪与PC机间串行通讯的设计与实现

文中研究了PC机和电网分析仪组成上位机和下位机之间的通讯过程,该通讯过程采用MODBUS协议。给出了用VB实现上位机监控软件的方法和下位机对上位机的通信实现     

广义四元数群的全自同构群

一个有限群Q4n称为广义四元群,若Q4n=〈a,b|a2n=1,b2＝an,ab=a-1〉,n≥3.根据广义四元群Q4n的结构和性质,利用群的扩张理论,先确定了Q4p与Q4pm的全自同构群的结构,由此归纳出一般的广义四元群Q4n的全自同构群的结构如下:设p1为n的最小素因子,n=pr11 pr22…prkk为n的素数分解,那么(a)当p1＞2时,Aut(G)=〈α〉:(〈η1〉×〈η2〉×…×〈ηk〉);(b)当p1＝2时,Aut(G)=〈α〉:(〈η2〉×…×〈ηk〉), r1＝1〈α〉:(〈γ〉×〈η2〉×…×〈ηk〉), r1＝2〈α〉:(〈μ〉×〈ν〉×〈η2〉×…×〈ηk〉), r1≥3.     

Comments on scaling effect of reciprocity in BRDF study

Reciprocity principle is a common theory in electromagnetics and optics. It is also one of the general principles of the radiation transformation theory. However, in many remote sensing studies, this principle cannot be always supported by experimental data, especially when the scaling effect of the remote sensing image pixel is considered. The debate over the issue of whether the reciprocity principle can be used as a fundamental standard in evaluating the effectiveness of remote sensing observations has lasted for years. Using geometrical optics model, Li and Wan proved the existence of the scaling effect in applying the reciprocity principle to a remote sensing image pixel in 1998. In 2002, Snyder challenged Li's proof, and attempted to prove that reciprocity principle is universally valid without any scale limitation. In this paper, we will argue with Snyder's theory and point out that Snyder's theory had neglected an important condition used in Li's proof and, as a result, drawn the wrong conclusion. Here we will restate Li's condition in his demonstration and offer a further proof to verify that reciprocity principle cannot be applied unconditionally to the study of bi-directional reflectance distribution function (BRDF) of land surfaces in field or satellite remote sensing observation scale.     

Piecewise algebraic varieties

The piecewise algebraic variety is a generalization of the classical algebraic variety. This paper discusses some properties of piecewise algebraic varieties and their coordinate rings based on the knowledge of algebraic geometry.     

Relationship between the exposure dose of high intensity focused ultrasound and the heated necrosis element

Heated necrosis element of tissues is the basis for treating tumor by high intensity focused ultrasound (HIFU), so study on the relationship between the HIFU exposure dose and the heated necrosis element of tissues is of great significance for both HIFU clinical applications and basic research. Using Pennes and Rayleigh formulae the relationship between the exposure dose of an annular focused transducer and the heated necrosis element (I.e. Biological focused region) in a bovine liver in vitro at a depth of 2 cm is simulated in an exposure dose range with radiation sound intensity of 7000～25400 W/cm2 and exposure time of 0～20 s. The theoretical results appear to be in quite good agreement with the experimental ones. It is shown that on the basis of existing theories the heated necrosis element produced by HIFU exposure can be predicted. The deviation of the theory from the experiments under higher exposure dose has also been discussed.     

Comparative physical mapping of rice BAC clones linked to resistance genes Glh,Bph-3 and xa-5 in Oryza sativa L. and O. granulata Nees et Arn. ex Watt.

Oryza granulata Nees et Arn. ex Watt. is one of the three wild relatives of rice,which are the most valuable for study and utilization in China.In this study,the homology and physical locations of three rice resistance genes,Glh,Bph-3 and xa-5 are comparatively analyzed between O.sativa and O. granulata by Southern blotting and fluorescence in situ hybridization (FISH).The results of Southern blotting indicate that there exist homologous sequences of the tested RFLP markers in O. granulata.By using three bacterial artificial chromosome (BAC) clones scanned by the tested RFLP as probes, FISH signals are detected on both mitotic and pachytene chromosomes in O.sativa and O.granulata.Dual-color FISH demonstrates that two of the three BAC clones (14E16 and 38J9) are located on the short arm of the same chromosome pair in O. granulata. Additionally, colinearity is shown for the two clones between O.sativa and O.granulata. Another BAC clone 44B4 is located on the end of the short arm of other chromosome pair in these two species.Although the phylogenetic relationship between O.sativa and O.granulata is the most distinct in Oryza and these two species have evidently different biological features and ecological habits, the relative lengths and arm ratios of the detected chromosomes and the relative positions of the tested clone signals on chromosomes in O. granulata are quite similar to those in O. sativa.     

Simulation of meridional overturning in the upper layer of the South China Sea with an idealized bottom topography

The South China Sea (SCS) is the largest marginal sea in the northwestern Pacific. Several important water gateways exist around the SCS, such as Luzon Strait, Taiwan Strait, etc., that lie in the northeastern SCS, and others like Kalimantan Strait, Balawan Strait, etc., lie in the south. Luzon Strait connects the SCS and Pacific via the Philippine Sea, and its water exchange has significant impact on the interior circulations of the SCS[1]. Since direct observation data about the …     

SEM analysis of the changes of carbon layer structure of mesocarbon microbeads heat-treated at different temperatures

Mesocarbon microbeads (MCMB) with narrow size distribution, excellent sphericity and no obvious conglutination have been prepared with a coal tar pitch containing quinoline insolubles (QI) as the raw material. Optical microscopy and scanning electron microscopy (SEM) are used to examine the structure of the MCMB. It has been found that SEM technique shows the structural information of MCMB clearly in the form of micrographs even when the structure of MCMB is complex, while the optical technique is useful for analysis of the regular structure of the mesophase spheres but cannot be effectively used to analyze either the complex structure of the green MCMB or the structures of the further heat-treated ones at different temperatures. According to the characteristics of the carbon layers, the structures of the as-prepared MCMB in the present experiment could be classified as (I) Parallel Layer type structure and (2) Bent Layer type structure with the carbon layers gathering at one or two points in the MCMB. In the experiments, SEM is also utilized to investigate the structures of MCMB that are heat-treated at different temperatures. It has been found that the MCMB without any further heat-treatment show no layered-carbons, while the ones heat-treated at temperaturehigher than 1000℃ exhibit obvious layered carbons across their sections. When increasing the heat-treatment temperature, the carbon layers become thinner and flatter.     

Induction of nicotine in tobacco by herbivory and its relation to glucose oxidase activity in the labial gland of three noctuid caterpillars

Tobacco Nicotiana tabacum L. is a host plant ofHelicoverpa armigera (Huibner), Helicoverpa assulta Guenee and Spodoptera litura (Fabricius) (Lepidoptera, Noctuidae). The difference in leaf nicotine response to the feeding by these three larvae and the mechanical simulation of their feeding was examined by HPLC. Results indicated that nicotine induction was suppressed by H. armigera and H. assulta larvae feeding or by simulated damage treated with their labial glands extracts. The production of nicotine was also suppressed by the glucose oxidase from Aspergillus niger when it was treated on mechanically wounded leaf area. On the contrary, the nicotine production was stimulated by S. litura larva feeding or by simulated damage treated with its labial gland extract. Heat denature can not counteract the stimulation effect of the S. litura labial gland extracts to tobacco nicotine production. The glucose oxidase activity was detected in labial gland extracts of both H. armigera and H. assulta, but the activity in H. armigera was significantly higher than that in H. assulta. No glucose oxidase activity was detected in labial gland extracts of S. litura. It is shown that the glucose oxidase activity in labial glands of caterpillars plays an important role in the nicotine response to herbivory. The glucose oxidase was mainly contained in the labial gland of H. armigera larva, and had the highest activity at pH 7.0. D-Glucose was the optimal substrate of the glucose oxidase. Labial gland glucose oxidase activities varied daily during larval development with high activities found when larvae were actively feeding.     

Analysis of carbon isotopes in airborne carbonate and implications for aeolian sources

Methods were developed to determine the mass ratios of carbon isotopes in trace amounts of aerosol carbonate. A Finnigan MAT 252 mass spectrometer fitted with an on-line Kiel device was to determine the ^13C/^12C ratio in CO2 produced from the carbonate. A study using these methods was conducted to characterize the carbonate carbon isotopes in aerosol samples collected in Xi‘an on dusty and normal days during March and April 2002. Results of the study demonstrate that insights into the origin of the dust can be deduced from its isotopic composition. That is, the δ^13C ofcarbonate for dust storm samples ranged from -1.4‰ to -4.2‰, and this is consistent with sandy materials in dust source regions upwind. In contrast, for non-dusty days δ^13C ranged from -7.5% to -9.3‰, which is more similar to fine particles emitted from local surface soils. Comparisons of dust storm aerosols with surface soils from source regions and with aerosol samples collected downwind indicate that the δ^13C values did not change appreciably during longrange transport. Therefore, carbon isotopes have the potential for distinguishing among source materials, and this approach provides a powerful new tool for identifying dust provenance.