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151.
王龙  Cao  Zhiqiang  Tan  Min  Wang  Shuo 《高技术通讯(英文版)》2007,13(4):343-349
A mechanical design method of robot fish is introduced in this paper.Based on this method an antonomous 3-Dimension(3D)locomotion robot fish with two pectoral fins and a caudal fin is developed.The pectoral fin mechanism has 3 degrees of freedom(3-DOFs),which enables the robot fish to realize yawing and pitching motions by controlling two pectoral fins.And the caudal fin mechanism is designed based on fish body wave curve fitting.The forward velocity can be adjusted by changing the caudal mechanism's oscillating frequency.Finally a physical implementation of the robot fish and experimental results are given.  相似文献   
152.
Rigorous proofs are given for the representations of real and complex stability radii of 2-dimensional linear systems. This representations can be used to analyze the robustness of a nominal 2-dimensional linear system under pelturbation of the system parameters, in particular testing the effect of numerical algorithms which are used to calculate the real stability radii of higher dimensional piecewise-linear systems.  相似文献   
153.
Waist-hip ratio (WHR) is a measure of body fat distribution and a predictor of metabolic consequences independent of overall adiposity. WHR is heritable, but few genetic variants influencing this trait have been identified. We conducted a meta-analysis of 32 genome-wide association studies for WHR adjusted for body mass index (comprising up to 77,167 participants), following up 16 loci in an additional 29 studies (comprising up to 113,636 subjects). We identified 13 new loci in or near RSPO3, VEGFA, TBX15-WARS2, NFE2L3, GRB14, DNM3-PIGC, ITPR2-SSPN, LY86, HOXC13, ADAMTS9, ZNRF3-KREMEN1, NISCH-STAB1 and CPEB4 (P = 1.9 × 10?? to P = 1.8 × 10???) and the known signal at LYPLAL1. Seven of these loci exhibited marked sexual dimorphism, all with a stronger effect on WHR in women than men (P for sex difference = 1.9 × 10?3 to P = 1.2 × 10?13). These findings provide evidence for multiple loci that modulate body fat distribution independent of overall adiposity and reveal strong gene-by-sex interactions.  相似文献   
154.
朱晶  Guo  Zheng  Yang  Da  Zhang  Min  Wang  Jing  Wang  Chenguang 《高技术通讯(英文版)》2008,14(4):437-442
In this paper, we firstly identify the functional modules enriched with differentially expressed genes (DEGs) and characterized by biological processes in specific cellular locations, based on gene ontology (GO) and microarray data. Then, we further define and filter disease relevant signature modules according to the ranking of the disease discriminating abilities of the pre-selected functional modules. At last, we analyze the potential way by which they cooperate towards human disease. Application of the proposed method to the analysis of a liver cancer dataset shows that, using the same false discovery rate ( FDR ) threshold, we can find more biologically meaningful and detailed processes by using the cellular localization information. Some biological evidences support the relevancy of our biological modules to the disease mechanism.  相似文献   
155.
The correlation between echolocation sound and morphological features of 18 species of bats, which are subordinated to 3 families including rhinolophidae, hipposideridae and vespertilionidae is studied. Pearson's correlation and regression analysis are adopted to analyze the correlations between noseleaf width (NW) and forearm length (FAL), NW and dominant frequency (DF), FAL and DF. The results show a positive correlation between NW and FAL and a negative correlation between NW and DF in Rhinolophidae. In each family, there is a negative correlation between FAL and DF. Some species have a higher or lower frequency than predicted one according to their body size. There are significant differences of the regression equation of FAL and DF among the three families. For the bats with the same body size, the order in frequency is: hipposiderid bats> rhinolophid bats> vespertilionid bats. The mechanism of interrelationship between FAL and DF of bats, the reason why these deviations occur in correlativity of the three families and the mechanism of the interaction between morphological, physiological and ecological characteristics are discussed.  相似文献   
156.
企业数据仓库与决策支持系统   总被引:4,自引:0,他引:4  
介绍了数据仓库(DW)、联机分析处理(OLAP)和数据挖掘(DM)的概念和功能,提出了将DW,OLAP和DM三种技术相结合的企业决策支持系统结构框架。  相似文献   
157.
Social media like Twitter who serves as a novel news medium and has become increasingly popular since its establishment. Large scale first-hand user-generated tweets motivate automatic event detection on Twitter. Previous unsupervised approaches detected events by clustering words. These methods detect events using burstiness,which measures surging frequencies of words at certain time windows. However,event clusters represented by a set of individual words are difficult to understand. This issue is addressed by building a document-level event detection model that directly calculates the burstiness of tweets,leveraging distributed word representations for modeling semantic information,thereby avoiding sparsity. Results show that the document-level model not only offers event summaries that are directly human-readable,but also gives significantly improved accuracies compared to previous methods on unsupervised tweet event detection,which are based on words/segments.  相似文献   
158.
Trace Na sources, extraction dynamics of trace Na, and influences of calcination temperature on quartz lattice, fluid inclusions, and muscovite were studied in detail herein for trace Na extraction from the quartz ore with water leaching at 90℃. Experimental results suggested that the trace Na sources included quartz lattice, fluid inclusions, and muscovite. The extraction rate of the trace Na in quartz ores can reach 31.0wt% after calcination at 900℃ for 5 h and water leaching at 90℃ for 24 h. The extraction process consisting of the dissolution of unfree Na and diffusion of free Na was dominated by calcination temperature. Calcination at 900℃ for 5 h was effective for extraction of the trace Na in fluid inclusions and muscovite. The extraction of the trace Na was mainly affected by the decrepitation of fluid inclusions when the calcination temperature ranged from 400 to 600℃ and by the damage of muscovite when the calcination temperature ranged from 600 to 900℃. Based on the extraction rates at different calcination temperatures, approximately 20.1wt% of the trace Na occurred in fluid inclusions, approximately 10.9wt% existed in muscovite, and 69.0wt% mainly occurred in quartz lattice.  相似文献   
159.
The influence of Nd addition on the glass-forming ability (GFA), microhardness, and corrosion resistance of Mg60-xCu40Ndx (x=5, 10, 15, 20, and 25, at%) alloys were investigated by differential scanning calorimetry, Vickers-type hardness tests, and electrochemical methods. The results suggest that the GFA and microhardness of the amorphous alloys increase until the Nd content reaches 20at%. The corrosion potential and corrosion current density obtained from the Tafel curves indicate that the Mg35Cu40Nd25 ternary alloy exhibits the best corrosion resistance among the investigated alloys. Notably, nanoporous copper (NPC) was synthesized through a single-step dealloying of Mg60-xCu40Ndx (x=5, 10, 15, 20, and 25) ternary alloys in 0.04 mol·L-1 H2SO4 solution under free corrosion conditions. The influence of dealloying process parameters, such as dealloying time and temperature, on the microstructure of the ribbons was also studied using the surface diffusivity theory. The formation mechanism of dealloyed samples with a multilayered structure was also discussed.  相似文献   
160.
Cu(In,Ga)Se2 (CIGS) thin films were prepared by directly sputtering Cu(In,Ga)Se2 quaternary target consisting of Cu:In:Ga:Se 25:17.5:7.5:50 at%. The composition and structure of CIGS layers have been investigated after annealing at 550 ℃ under vacuum and a Se-containing atmosphere. The results show that recrystallization of the CIGS thin film occurs and a chalcopyrite structure with a preferred orientation in the (112) direction was obtained. The CIGS thin film annealed under vacuum exhibits a loss of a portion of Se, while the film annealed under Se-containing atmosphere reveals compensation of Se. Several solar cells with three different absorber thicknesses were fabricated using a soda lime glass/Mo/CIGS/CdS/i-ZnO/ZnO:Al/Al grid stack structure. The highest conversion efficiency of 9.65% with an open circuit voltage of 452.42 mV, short circuit current density of 32.16 mA cm2 and fill factor of 66.32% was obtained on a 0.755 cm2 cell area.  相似文献   
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