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911.
912.
Female cowpea weevils,Callosobruchus maculatus (F.), emitted a pheromone which excited males. Pheromone release began soon after emergence and continued for one week. Synchronization of pheromone release with calling behavior was demonstrated. Mating reduced pheromone release but not male response. Pheromone obtained by aeration collection was utilized for determining a quantitative dose-response relationship.Mention of a commercial product does not constitute an endorsement by the USDA.Visiting scholar on leave from Shanghai Institute of Entomology, PRC. 相似文献
913.
利用重组NS4抗原及合成肽5-11抗原分别检测5例输血后丙型肝炎患者的系列血清136份,并与HCV总抗体及HCVRNA检测结果比较,发现抗NS4抗体的动态变化虽然有两种模式,但在多数情况下为一种模式,即抗体阳转后很少转阴,并且其动态变化基本与总抗体相似。同时发现2例病人抗NS4抗体阳转时间早于总抗体,因此,推测HCV检测试剂中增加NS4抗原可能对提高HCV诊断试剂的灵敏度有一定意义。 相似文献
914.
Experimental Study of an EMG-Controlled 5-DOF Anthropomorphic Prosthetic Hand for Motion Restoration
Dapeng Yang Li Jiang Qi Huang Rongqiang Liu Hong Liu 《Journal of Intelligent and Robotic Systems》2014,76(3-4):427-441
In this paper, we attempted to evaluate the performance of an electromyography (EMG)-controlled 5-DOF prosthetic hand on ten transradial amputees. The proposed prosthesis is composed of a five-fingered hand, a passive wrist, and a customized socket for each subject. The EMG control methods included both a commonly used pattern recognition-based scheme (DD-SVM) and a novel digital encoding strategy (double-channel template matching (DCTM)). A virtual 3D hand platform was developed for training the subjects and rapidly testing the control methods. For each subject, the performance of the EMG control methods was firstly measured by off-line classification accuracy; then, according to the accuracy, a particular control method was selected and embedded in the EMG controller for further validation on ordinary daily life activities. Our experiments were conducted to test not only the hand’s grasp ability but also other multifinger cooperation skills. The result indicated that the subjects of rich control experience can accomplish several intuitive motion control over their hands. However, the kinds of the motions and their relative recognition accuracy may depend on some individual differences, such as the amputation level, the activity of the residual nerve-muscle system, and the richness of control experience. Meanwhile, the proposed digital encoding method, DCTM, which only utilized two channels of EMG, was necessary for those amputees with few available control signals. This paper suggested that the EMG control method should be differently considered according to the particular condition of each subject. 相似文献
915.
The miscibility and morphology of poly(caprolactone) (PCL) and poly (4-vinylphenol) (PVPh) blends were investigated by using differential scanning calorimetry (DSC), Fourier transform infrared (FTIR) spectroscopy and 13C solid state nuclear magnetic resonance (NMR) spectroscopy. The DSC results indicate that PCL is miscible with PVPh. FTIR studies reveal that hydrogen bonding exists between the hydroxyl groups of PVPh and the carbonyl groups of PCL. 13C cross polarization (CP)/magic angle spinning (MAS)/dipolar decoupling (DD) spectra of the blends show a 1 ppm downfield shifting of 13C resonance of PVPh hydroxyl-substituted carbons and PCL carbonyl carbons with increasing PCL content. Both FTIR and NMR give evidence of inter-molecular hydrogen bonding within the blends. The proton spin-lattice relaxation in the laboratory frame, T1(H), and in the rotating frame, T1ρ(H), were studied as a function of the blend composition. The T1(H) results are in good agreement with thermal analysis; i.e. the blends are completely homogeneous on the scale of 50-80 nm. The T1ρ(H) results indicate that PCL in the blends has both crystalline and amorphous phases. The amorphous PCL phase is miscible with PVPh, but the PCL crystal domain size is probably larger than the spin-diffusion path length within the T1ρ(H) time-frame, i.e. larger than 2-4 nm. The mobility differences between the crystalline and amorphous phases of PCL are clearly visible from the T1ρ(H) data. 相似文献
916.
917.
硫代糠酸乙酯和硫代糠酸糠酯的合成 总被引:2,自引:0,他引:2
以糠酰氯、乙硫醇、糠硫醇为原料,合成了硫代糠酸乙酯和硫代糠酸糠酯,产率分别为77%和74%。测定了硫代糠酸乙酯的沸点、折光率及硫代糠酸糠酯的熔点、沸点。对合成的硫代糠酸乙酯进行了评香鉴定 相似文献
918.
磁性Fe3O4纳米颗粒制备方法的比较 总被引:1,自引:0,他引:1
使用醇-水法、氢氧化钠共沉淀法和氨水共沉淀法制备磁性Fe3O4纳米颗粒.制得的纳米Fe3O4用饱和油酸钠的醇溶液进行改性.采用XRD,SEM,TEM,IR和振动样品磁强计等手段对制备的样品进行了表征研究.实验结果表明三种方法中,醇-水法和氨水共沉淀法所制备的纳米Fe3O4表面改性效果良好;氨水共沉淀法制备的颗粒磁性最强,但实验时间长;醇-水法制备的粉体粒径最小,但颗粒分散情况相对较差;氢氧化钠共沉淀法最简单,实验时间最短,收率也较高,但粉体性能不如其它两种. 相似文献
919.
改性低毒脲醛树脂的合成及性能研究 总被引:1,自引:0,他引:1
采用六亚甲基四胺做催化剂,加入聚乙烯醇(PVA)、三聚氰胺和硫脲作为改性剂,通过降低甲醛与尿素物质的量比、采用尿素分批加入的合成方法,制备出改性低毒的脲醛树脂(UF),使游离甲醛质量分数低于0.30%;采用捏合和模压成型方法,将改性和普通UF树脂分别与剑麻纤维(SF)制备UF/SF共混复合材料,研究了复合材料的力学性能和吸水性能。结果表明,甲醛和尿素物质的量比为1.1时,游离甲醛质量分数降低到0.16%;甲醛和尿素物质的量比为1.2时,三聚氰胺、PVA及硫脲加入量分别为尿素总量的2.0%,1.5%,1.0%(质量分数)时,游离甲醛质量分数降低到了0.10%,粘度达到0.41Pa·S,贮存期大于80d;改性UF/SF复合材料的性能比普通UF/SF复合材料的冲击性能和耐磨性能分别提高了114%和261%。 相似文献
920.
掺粉煤灰的橡塑复合材料研究和开发 总被引:2,自引:0,他引:2
概述了粉煤灰再利用的必要性及掺有粉煤灰的橡塑复合材料的应用研究和开发概况,介绍了国内橡塑粉煤灰复合材料的研究及开发进展,综述了橡塑粉煤灰复合材料的应用。 相似文献