探析新疆农产品电子商务的模式选择

在分析农产品电子商务基本模式的基础上,结合新疆农业发展的特点,以及当前农产品电子商务发展面临的问题和机遇,综合阐述了新疆农产品电子商务发展的模式选择。     

Study on The Mode of Sectional Even Mass Cantilever of Silos And the Analysis Method of Infinite Degree of Freedom

In this paper,a new mode of sectional even mass cantilever of silos was established and an analysis of infinite degree of freedom for it was carried out.In the end,a calculation example of this precise,reliable and practical mode was given.     

榆林市大保当镇现代化小镇发展模式探析

以矿产能源集中、经济发展迅速的榆林市为研究对象,分析其快速增长的经济与人居环境高度破坏的核心问题,以大保当镇为例,从地理区位、产业结构、经济形态、镇区格局等方面进行研究分析,总结出一套适合于产业型小城镇建设发展的规划模式,即政企合作、城乡统筹、集中建设“现代化小镇”,确保大保当镇经济、社会、环境的可持续发展,并为其他城镇的发展提供经验与借鉴。     

几种地下水脆弱性评价方法之比较

地下水脆弱性研究是保护地下水环境工作的基础。对地下水脆弱性进行评价,可为合理地保护、开发和利用地下水资源,实现地下水资源的可持续利用提供有益参考。应用熵权系数法、基于RAGA的投影寻踪模型以及多目标模糊模式识别模型等几种模型对三江平原地下水脆弱性进行评价,得出评价结果。将结果进行横向比较,分析几种评价方法各自的优缺点,为地下水脆弱性的评价提供新的思路和方法。     

浅析地埂林草建设技术

地埂林草建设是宁夏山区"三田"和生态建设的一项重要内容,根据小流域综合治理实践,就林草建设方法、配置模式、林草品种等进行了对比分析。试验结果表明,宜选择柠条、柽柳、杞柳作为地埂造林的主要树种,新疆杨作为地埂底部造林的主要树种;在光、热、水条件较好的地方,地埂造林可以考虑种植花椒等经济林木;牧草中紫花苜蓿的耗水量较低,可作为梯田地埂种草的主要草种。     

Germplasm characterization of Sesbania accessions based on isozyme analyses

Twenty-two accessions belonging to seven species of Sesbania Scop. (S. emerus, S. exasperata, S. grandiflora, S. rostrata, S. sesban, S. tetrapteraand S. virgata), were evaluated in order to characterize the isozyme electrophoretic patterns and to estimate their genetic variability and outcrossing rates. Eight isozyme systems were used: acid phosphatase (ACP), isocitrate dehydrogenase (IDH), phosphoglucomutase (PGM), malate dehydrogenase (MDH), phosphoglucoisomerase (PGI), glutamate oxaloacetate transaminase (GOT), peroxidase (PRX) and catalase (CAT), with two gel/electrode buffers and distilled water as the extraction buffer. Cotyledons were chosen for enzyme extraction. The accessions were compared considering the presence/absence of bands for each system. A dendrogram was obtained using the Jaccard similarity index and the UPGMA clustering method, classifying the accessions into eight groups, evidencing both inter- and intraspecific variability. Annual species were classified in one major group separate from the perennials (S. grandiflora, S. sesban, S. virgata), which were allocated into two other main groups. S. virgata accessions (subgenus Daubentonia) were clearly separated from the other species. Isozyme banding patterns for the accessions are presented for each system. A high incidence of intraspecific monomorphism was observed. Interpretation in terms of loci and alleles was made for S. sesbanand S. virgataaccessions, which presented polymorphism for the systems PGI, GOT (S. sesban) and MDH (S. virgata). The average expected heterozygosity estimates varied from 0.0 to 0.231 for S. sesban and 0.0 to 0.20 for S. virgata. A mean number of 2.0 alleles per locus was observed for both species. Population multilocus outcrossing rate (t _m) of 0.62 was estimated for S. sesban, indicating a partial allogamy mode of reproduction. Individual families presented multilocus rates varying from 0.00 to 1.00, indicating both self-pollination and cross-pollination.     

探索水产院校学生信息素质教育与服务创新

信息素质主要表现为信息意识、信息能力、信息知识和信息道德。在分析水产院校学生信息素质现状的基础上,结合实践,对21世纪水产院校信息素质教育的改进及服务创新进行了有益的探索。     

基于装配约束的鹤式起重机模态分析

基于四连杆机构理论,在UG环境下搭建了简化的鹤式起重机三维实体模型,运用ADAMS软件对其进行了装配约束下各零部件的模态振型分析,为改进其结构设计和避免结构共振做了有益探索。     

稳态加载工况(ASM)测试程序运行试验

在系统试验前期准备的基础上,对ASM系统进行运行试验,得出试验结果。系统软件完全根据ASM工况要求设计。系统在软件抗干扰设计中采用了数字滤波技术,从软件方面保证了数据采集的精确性。该软件系统综合了VB串口通讯技术、VB数据库接口技术、SQL Sever2000数据库存储技术、网络技术、数据库远程存储和读取技术。从本系统运行情况判断,系统控制灵活、运行稳定,数据采集精确,完全满足ASM工况测试需求。     

多模式并联机构操作模式变换方法研究

多模式并联机构可通过改变操作模式来满足不同功能性、适应性要求。为更好地实现多模式机构不同模式间的平稳变换,提出一种多模式并联机构的操作模式变换方法。首先,基于Study参数和代数几何对多模式并联机构进行可重构分析,获得机构的各种操作模式和变换位形;其次,对实际需要的操作模式和变换位形的合理驱动空间进行分析求解,将所有变换位形的驱动空间求交集,得到机构的驱动空间,并优选出最优的驱动组合;最后,采用TCI(整体运动/力约束性能指标)确定近似约束奇异空间,在该空间内采用冗余驱动的方式,使机构平稳实现操作模式之间的变换。以SNU 3-UPU机构为例,分析了3T模式与2T1R模式之间的变换过程,并通过仿真验证了该方法的正确性。