“长安之星”微型客车车架刚度研究

通过试验和数值模拟,反求“长安之星”车架结构的弯曲和扭转刚度,建立了适用于“长安之星”车架结构的弯曲和扭转刚度测试的试验台,对其弯曲和扭转刚度进行了试验研究。在试验基础上,模拟了刚度测试过程中的约束和加载条件,进行了车架结构刚度的有限元分析。计算和试验结果的对比表明,二者吻合得较好。该研究结果为同类车型开发、改型及优化设计提供了技术手段和依据。

复方银黄微型灌肠剂对发热大鼠下丘脑前列腺素E_2受体表达的影响

目的:观察复方银黄微型灌肠剂(YHCE)对发热大鼠下丘脑中前列腺素E2受体EP1、EP4mRNA表达的影响。方法:大鼠皮下注射20%酵母混悬液造发热模型,复方银黄微型灌肠剂按35.84g/kg于造模1h后灌肠给药;给药后4h取大鼠下丘脑组织,用实时荧光定量聚合酶链反应检测各组大鼠下丘脑中EP1、EP4受体mRNA表达的相对差异。结果:与发热对照组比,YHCE组的EP1、EP4受体mRNA相对表达量减少。结论:复方银黄微型灌肠剂可抑制发热组大鼠下丘脑中前列腺素E受体EP1、EP4mRNA的表达。

走向战场的微型“空中飞鸟”

在3月20日开始的美、英对伊战争中，在伊上空不时出现一些不明身份的像鸟一般大小的飞行物，它就是20世纪90年代初期开始发展起来的微型空中飞行器。其基本特征是：重量为10-100克，有效载荷1—18克，续航时间20—60分钟．巡航速度35—70千米/小时，航程1—10千米(用机炮发射可达20千米以上)。外形采用固定翼、旋翼或其布局，酷似各种昆虫或小飞鸟。最佳使用高度为几十—几百米，单价不超过1000美元。

空中迷你魔幻杀手大透视

随着现代科技的迅猛发展，微型技术开始用到新型战机和导弹上，使新世纪战机和导弹显得更为“精练”，但威力依然不小，让人不得不刮目相看。

Microsatellite Genotyping for Four Expected Inbred Mouse Strains from KM Mice

Chinese Kun Ming （KM） mouse, an outbreed strain of laboratory animal, has been widely utilized in related pharmaceutical and genetic studies throughout China. However, the value of KM mice to the research community has been severely limited, partially due to the fact that well-characterized inbred strain of KM mice is not available. Several expected inbred strains from KM mice have been bred, but their genetic purity remains uncertain. In this study, four expected inbred strains of KM mice （A1, T2, N2, and N4） were chosen and their inbred degree were compared with two classical inbred mouse lines （BALB/c and C57BL/6） by analyzing the genotypes of about 30 microsatellite markers. In the four strains, A1 and N4 were homozygous at all genotyped loci, but N2 and T2 were only heterozygous at locus D15Mit16. These results indicate that the level of genetic purity/homozygousity of A1, N4, N2, and T2 inbred line is comparable to those of BALB/c and C57BL/6. This study provided the first and solid evidence for genetic purity of four expected inbred strains of KM mice. These 4 inbred mice strains should be well maintained for further characterization and utilization in genetic studies.

Estimated reproductive success of brooders and heritability of growth traits for large yellow croaker (Larimichthys crocea) using microsatellites

We estimated the reproductive success of adult brood fish and the heritability of growthrelated traits for large yellow croaker （Larimichthys crocea）. We created two independent full-factorial cross groups （1 and 2） by crossing 4 malesx4 females and 4 males^3 females, respectively. We measured the body weight （BW）, body length （BL）, and body height （BH） of 281 individuals from group 1 and 318 individuals from group 2 at 20 months post hatch （harvest age）. We also collected a tissue sample from each individual. The parents and offspring were genotyped using six polymorphic mierosatellites. Of the 599 offspring, 99.2% were assigned to a single pair of parents. In both groups, some parent pairs produced a large number of offsprings while other pairs did not produce any offspring. The genetic diversity and putative No were lower in the offsprings than in the parents in both groups. The heritability estimates at 20-month age were 0.13±0.10 for BW, 0.19±0.13 for BL, and 0.09±0.06 for BH. The genetic and phenotype correlation between BW, BL, and BH was close to 1. The results provide basic information for selective breeding and further genetic characterization of large yellow croaker.

Inheritance of 15 microsatellites in the Pacific oyster Crassostrea gigas:segregation and null allele identification for linkage analysis

Microsatellites were screened in a backcross family of the Pacific oyster, Crassostrea gigas. Fifteen microsatellite loci were distinguishable and polymorphic with 6 types of allele-combinations. Null alleles were detected in 46.7% of loci, accounting for 11.7% of the total alleles. Four loci did not segregate in Mendelian Ratios. Three linkage groups were identified among 7 of the 15 segregating loci. Fluorescence-based automated capillary electrophoresis (ABI 310 Genetic Analyzer) that used to detect the microsatellite loci, has been proved a fast, precise, and reliable method in microsatellite genotyping.

Design and analysis of the reliability of on-board computer system based on Markov-model

An on-board computer system should have such advantages as light weight,small volume and low power to meet the demand of micro-satellites. This paper, based on specific characteristics of Stereo Mapping Micro-Satellite (SMMS), describes the on-board computer system with its advantage of having centralized and distributed control in the same system and analyzes its reliability based on a Markov model in order to provide a theoretical foundation for a reliable design. The on-board computer system has been put into use in principle prototype model of Stereo Mapping Micro-Satellite and has already been debugged. All indexes meet the requirements of the design.

Semi-supervised kernel FCM algorithm for remote sensing image classification

These problems of nonlinearity, fuzziness and few labeled data were rarely considered in traditional remote sensing image classification. A semi-supervised kernel fuzzy C-means （SSKFCM） algorithm is proposed to overcome these disadvantages of remote sensing image classification in this paper. The SSKFCM algorithm is achieved by introducing a kernel method and semi-supervised learning technique into the standard fuzzy C-means （FCM） algorithm. A set of Beijing-1 micro-satellite＇s multispectral images are adopted to be classified by several algorithms, such as FCM, kernel FCM （KFCM）, semi-supervised FCM （SSFCM） and SSKFCM. The classification results are estimated by corresponding indexes. The results indicate that the SSKFCM algorithm significantly improves the classification accuracy of remote sensing images compared with the others.

Brazilian Buffalo Genetic Variability by Cross-Specific Microsatellite Set

Buffaloes （Bubalus bubalis） are widely distributed and were introduced to Brazil in 1895. Most of the molecular genetic characterization of buffaloes has been done with cross-specific （cattle） markers, but few of them include Brazilian populations. Nineteen commonly used cattle microsatellites were tested to develop a multiplexed set of microsatellites and characterize Brazilian buffalo. Three PCR mixes were finally developed with the 11 markers that succeed in amplify and were polymorphic （58%）. The average number of alleles was 5.42, with an average observed and expected heterocigozity of 0.441 and 0.695, respectively. As it was expected, Brazilian buffalo variability was lower than the previously reported from the domestication centres （China and India）, but higher than the seriously selected European populations. The exclusion power calculated for the eleven markers in Brazilian buffalo was 0.9999999996, this allows its use in DNA based traceability.

Bifurcation and chaos study on transverse-torsional coupled 2K-H planetary gear train with multiple clearances

A new non-linear transverse-torsional coupled model was proposed for 2K-H planetary gear train, and gear's geometric eccentricity error, comprehensive transmission error, time-varying meshing stiffness, sun-planet and planet-ring gear pair's backlashes and sun gear's bearing clearance were taken into consideration. The solution of differential governing equation of motion was solved by applying variable step-size Runge-Kutta numerical integration method. The system motion state was investigated systematically and qualitatively, and exhibited diverse characteristics of bifurcation and chaos as well as non-linear behavior under different bifurcation parameters including meshing frequency, sun-planet backlash, planet-ring backlash and sun gear's bearing clearance. Analysis results show that the increasing damping could suppress the region of chaotic motion and improve the system's stability significantly. The route of crisis to chaotic motion was observed under the bifurcation parameter of meshing frequency. However, the routes of period doubling and crisis to chaos were identified under the bifurcation parameter of sun-planet backlash; besides, several different types of routes to chaos were observed and coexisted under the bifurcation parameter of planet-ring backlash including period doubling, Hopf bifurcation, 3T-periodic channel and crisis. Additionally, planet-ring backlash generated a strong coupling effect to system's non-linear behavior while the sun gear's bearing clearance produced weak coupling effect. Finally, quasi-periodic motion could be found under all above–mentioned bifurcation parameters and closely associated with the 3T-periodic motion.

Evaluation of Barley Genotypes for Resistance to Pyrenophora Teres Using Molecular Markers

Net blotch disease caused by the fungus Pyrenophora teres belongs to the complex of leaf blotch diseases that decrease the yield and the quality of barley （Hordeum vulgate L.）. This study deals with the use of microsatellites localized nearby the quantitative trait loci, associated with the resistance to P. teres to screen barley lines and varieties that could be introduced into a net blotch resistance breeding program. Thirty-five barley microsatellite loci and 65 barley genotypes, 265 alleles were detected. The number of alleles per locus ranged from 2 to 26. The arrangement of genotypes into clusters based on microsatellite data does not correspond to their resistance level to P. teres even though chosen microsatellite markers have been localized nearby QTLs associated with the resistance to P. teres.

Confirmation of susceptibility gene loci on chromosome 1 in Northern China Han families with type 2 diabetes

Objective To confirm previous effort to identify type 2 diabetes susceptibility genes in a Northern Chinese population by conducting a new genome scan with both an increased number of type 2 diabetes families and a new set of microsatellite markers within the previously localized regions.Methods A genome scan method was applied. After multiplexed PCR, electrophoreses, genescan and genotyping analysis, we obtained size information for all loci , and then a further study was done by both parametric and non-parametric linkage analysis to investigate the P values and Z values of these loci.Results We surveyed 34 microsatellite markers which distributed within 5 regions along chromosome 1, and a total of 12?000 genotypes were screened. Evidence of linkage with diabetes was identified for 8 of the 34 loci. All P values of the 8 loci were lower than 0.05, and the highest Z value was 2.17. A very interesting finding is that all 5 markers at the p- terminal 1p36.3-1p36.23 region, spanning a long range of 16.9?cM, were identified to have a low P value of less than 0.05, which suggests that this region may contain multiple susceptibility genes. Regions 4 and 5 also confirmed the previous findings, and we narrowed these two regions to a 2.7?cM and 2.5?cM regions, respectively.Conclusions We further confirmed the results gained in the previous genome-wide scan using an increased number of NIDDM families and a new set of microsatellite markers lying within the initially localized regions. The fact that all 5 loci at the p- terminal region displayed a low P value of less than 0.05 suggests that more than 1 susceptibility gene may reside in this region.

Attitude stabilization of a pico-satellite by momentum wheel and magnetic coils

The three-axis active attitude control method with a momentum wheel and magnetic coils for a pico-satellite is considered. The designed satellite is a 2.5 kg class satellite stabilized to nadir pointing. The momentum wheel performs a pitch-axis momentum bias, nominally spinning at a particular rate. Three magnetic coils are mounted perpendicularly along the body axis for precise attitude control through the switch control mechanism. Momentum wheel start up control, damping control and attitude acquisition control are considered. Simulation results show that the proposed combined control laws for the pico-satellite is reliable and has an appropriate accuracy under different separation conditions. The proposed strategy to start up the wheel after separation from the launch vehicle shows that its pitch momentum wheel can start up successfully to its nominal speed from rest, and the attitude convergence can be completed within several orbits, depending on separation conditions.

Wind estimation around the shipwreck of Oriental Star based on field damage surveys and radar observations

Based on observational analyses and on-site ground and aerial damage surveys, this work aims to reveal the weather phenomena--especially the wind situation--when Oriental Star capsized in the Yangtze River on June 1, 2015. Results demonstrate that the cruise ship capsized when it encountered strong winds at speeds of at least 31 m s ^-1 near the apex of a bow echo embedded in a squall line. As suggested by the fallen trees within a 2-kin radius around the wreck location, such strong winds were likely caused by microburst straight-line wind and/or embedded small vortices, rather than tomadoes.

Atmospheric density determination using high-accuracy satellite GPS data

Atmospheric drag is the main source of error in the determination and prediction of the orbit of low Earth orbit （LEO） satellites; however, empirical models that are used to account for this often have density errors of around 15%-30%. Atmospheric density determination has thus become an important topic for researchers. Based on the relationship between file atmospheric drag force and the decay of the semi-major axis of the orbit, we derived atmospheric density along the trajectory of challenging mini-satellite payload （CHAMP） satellite with its rapid science orbit （RSO） data. Three primary parameters--the ratio of cross-sectional area to mass, the drag coefficient, and the decay of the semi-major axis caused by atmospheric drag--were calculated. We also analyse the source of the error and made a comparison between the GPS-derived and reference density. The result for December 2, 2008, showed that the mean error of the GPS-derived density could be decreased from 29.21% to 9.20%, if the time span adopted for the process of computation was increased from 10 min to 50 min. The result for the entire month of December indicated that a density precision of 10% could be achieved, when the time span meets the condition that the amplitude of the decay of the semi-major axis is much greater than its standard deviation.

Relationships between Genetic Diversity of Vascular Plant Species and Climate Factors

Genetic diversity is crucial for plants to respond to global climate change,and exploring relationships between genetic diversity and climatic factors may help predict how global climate change will shape the genetic diversity of plants in the future.So far,however,the extent and magnitude of the impact of climatic factors on the genetic diversity of plants has not been clarified.We collected data from 68published papers on two widely used measures of genetic diversity of populations (average expected heterozygosity (He)and average observed heterozygosity (Ho))and on localities of populations of 79vascular plants,and extracted data on 19 climatic factors from WorldClim.We then explored the relationships between measures of genetic diversity and climatic factors using linear regressions.He of plant populations was significantly correlated with climatic factors in 58.7%(44)of the 75 species that used He as a measure of genetic diversity,and Ho was correlated with climatic factors in 65.1% (41)of the 63 species that used this genetic diversity measure.In general,Mean Temperature of Wettest Quarter, Precipitation Seasonality,Precipitation of Driest Quarter and Temperature Seasonality played a vital role in shaping He,and Ho was mostly correlated with Precipitation of Warmest Quarter,Mean Temperature of Wettest Quarter, Precipitation of Driest Quarter and Precipitation of Driest Month.Also,the proportion of the significant correlations between genetic diversity of populations and climatic factors was higher for woody than for herbaceous species, and different climatic factors played different roles in shaping genetic diversity of these two growth forms.Our results suggest that climate may play an important role in shaping genetic diversity of plant populations,that climatic change in the future may alter genetic diversity of plants,and that genetic diversity of different plant forms may respond to climatic change differently.

Variation in sexual dimorphism and assortative mating do not predict genetic divergence in the sexually dimorphic Goodeid fish Girardinichthys multiradiatus

Sexual dimorphism is often used as a proxy for the intensity of sexual selection in comparative studies of sexual selection and diversification. The Mexican Goodeinae are a group of livebearing freshwater fishes with large variation between species in sexual dimorphism in body shape. Previously we found an association between variation in morphological sexual dimorphism between species and the amount of gene flow within populations in the Goodeinae. Here we have examined if mor- phological differentiation within a single dimorphic species is related to assortative mating or gene flow between populations. In the Amarillo fish Girardinichthys multiradiatus studies have shown that exaggerated male fins are targets of female preferences. We find that populations of the species differ in the level of sexual dimorphism displayed due to faster evolution of differences in male than female morphology. However, this does not predict variation in assortative mating tests in the laboratory; in fact dif- ferences in male morphology are negatively correlated with assortative mating. Microsatellite markers reveal significant genetic differences between populations. However, gene flow is not predicted by either morphological differences or assortative mating. Rather, it demonstrates a pattern of isolation by distance with greater differentiation between watersheds. We discuss the caveats of predicting behavioural and genetic divergence from so-called proxies of sexual selection [Current Zoology 58 （3）： 440-452, 2012].

Comparing the VGCG model as the unification of dark sectors with observations

Current observations indicate that 95% of the energy density in the universe is the unknown dark component.The dark component is considered composed of two fluids:dark matter and dark energy.Or it is a mixture of these two dark components,i.e.,one can consider it an exotic unknown dark fluid.With this consideration,the variable generalized Chaplygin gas(VGCG)model is studied with not dividing the unknown fluid into dark matter and dark energy parts in this paper.By using the Markov Chain Monte Carlo method,the VGCG model as the unification of dark sectors is constrained,and the constraint results on the VGCG model parameters are,n=0.00057+0.0001+0.0009-0.0006-0.0006,α=0.0015+0.0003+0.0017-0.0015-0.0015and B s=0.778+0.016+0.030-0.016-0.035,obtained by the cosmic microwave background data from the 7-year WMAP full data points,the baryon acoustic oscillation data from Sloan Digital Sky Survey(SDSS)and 2-degree Field Galaxy Redshift(2dFGRS)survey,and the Union2 type Ia supernova data with systematic errors.At last,according to the evolution of deceleration parameter it is shown that an expanded universe from deceleration to acceleration can be obtained in VGCG cosmology.

Interacting model of new agegraphic dark energy:observational constraints and age problem

Many dark energy models fail to pass the cosmic age test because of the old quasar APM 08279+5255 at redshift z=3.91,the ΛCDMmodel and holographic dark energy models being no exception.Inthis paper,we focus onthe topic of the age problem inthe new agegraphic dark energy(NADE)model.We determine the age of the universe in the NADE model by fitting the observational data,including type Ia supernovae(SNIa),baryon acoustic oscillations(BAO)and the cosmic microwave background(CMB).We find that the NADE model also faces the challenge of the age problem caused by the old quasar APM 08279+5255.In order to overcome such a difficulty,we consider the possible interaction between dark energy and dark matter.We show that this quasar can be successfully accommodated in the interacting new agegraphic dark energy(INADE)model at the 2σlevel under the current observational constraints.