共查询到20条相似文献，搜索用时 218 毫秒
1.
A cluster analyzing algorithm based on grids is introduced in this paper,which is applied to data mining in the city emergency system. In the previous applications, data mining was based on the method of analyzing points and lines, which was not efficient enough in dealing with the geographic information in units of police areas. The proposed algorithm maps an event set stored as a point set to a grid unit set, utilizes the cluster algorithm based on grids to find out all the clusters, and shows the results in the method of visualization. The algorithm performs well when dealing with high dimensional data sets and immense data. It is suitable for the data mining based on geographic information system and is supportive to decision-makings in the city emergency system. 相似文献
2.
The integration of water quality analysis simulation program （WASP） with a geographical information system （GIS） is presented.This integration was undertaken to enhance the data analysis and management ability of the widely used water quality model.Different types of data involved in WASP modeling were converted and integrated into GIS using a database method.The spatial data modeling and analysis capability of GIS were used in the operation of the model.The WASP water quality model was coupled with the environmental fluid dynamics code （EFDC） hydrodynamic model.A case study of the Lower Charles River Basin （Massachusetts,USA） water quality model system was conducted to demonstrate the integration process.The results showed that high efficiency of the data process and powerful function of data analysis could be achieved in the integrated model,which would significantly improve the application of WASP model in water quality management. 相似文献
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A power system with proton exchange membrane fuel cells (PEMFC) was designed for thermal underwater glider.Heat generated by PEMFC is used as the propulsion power of the glider,and the electricity is used in the control and sensor system.An electric energy storage system (ESS) is required which possesses high power density with good cycle life.Ultracapacitors which exhibit high power density and cycle life are considered as energy storage devices.Simulations based on a specific voyage condition indicate that ESS with ultracapacitors has positive effects on reducing the output power demand of PEMFC and lightening the power system.Experimental results show that the state of charge (SOC) is related to the capacitance and resistance in ultracapacitor ESS. 相似文献
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Objective: To construct a eukaryotic expression plasmid pcDNA3.1 (-)-Humanin. Methods: The recombinant plasmid pGEMEX-1-Humanin was digested with restriction endonucleases BamH I and Hind III and the Humanin gene fragments, about 100 bp length, were obtained. Then the Humanin gene fragments were inserted into eukaryotic expression vector pcDNA3.1 (-) and the recombinant plasmids pcDNA3, l(-)-Humanin were identified by sequencing. Results: Recombinant plasmid DNA successfully produced a band which had the same size as that of the Humanin positive control. The sequence of recombinant plasmids accorded with the Humnain gene sequence. Conclusions: A eukaryotic expression plasmid of Humanin was successfully constructed. 相似文献
5.
光栅投射技术在逆向工程中的应用 总被引：1，自引：0，他引：1
Acquisition of physical data with high precision is a key step in reverse engineering ( RE). It is an important stimulative for the progress of reverse engineering with which various digitizing devices are invented, developed and made applicable. This paper introduces a three dimensional optical measurement method based on digital fringe projection technique in RE to improve the technique through its application. A practical example is presented and the result demonstrates the applicability and feasibility of the measurement system as well as the reliability and validity of relevant methods and algorithms. 相似文献
6.
裘春晗 《上海大学学报(英文版)》2005,9(2):124-126
A computational model of water migration flux of fine porous soil in frost heave was investigated in a closed system. The model was established with the heat-mass conservation law and from some previous experimental results. Through defining an auxiliary function an empirical function in the water migration flux, which is difficult to get, was replaced. The data needed are about the water content along the soft colunm after test with enough long time. We adopt the test data of sample soil colunms in [1] to verify the model. The result shows it can reflect the real situation on the whole. 相似文献
7.
Portable 4-channel electrochemical noise test system 总被引：1，自引：1，他引：0
A portable 4-channel electrochemical noise(EN) test system with high precision was developed.The modular instrument cRIO was used as its core and the signal conditioning module included zero resistance ammeter(ZRA),fly line,screening box and shielded wire.The EN data were acquired from two Q235 carbon steel specimens placed in 0.5 mol/L H2SO4 solution and 0.1 mol/L NaCl solution.The experimental result shows that this system can achieve an accuracy of 10 pA and 10 μV,and it can be applied to on-site multi-channel EN test. 相似文献
8.
Yang Yiying Sun Qingqing Liu Yang Yin Hanzhi Yang Wenping Wang Yang Liu Ying Li Yuxian Pang Shen Liu Wenxi Zhang Qian Yuan Fang Qiu Shiwen Li Jiong Wang Xuefeng Fan Keqiang Wang Weishan Li Zilong Yin Shouliang 《Journal of Zhejiang University. Science. B》2021,22(5):383-396
Streptomyces produces many valuable and important biomolecules with clinical and pharmaceutical applications. The development of simple and highly efficient gene editing tools for genetic modification of Streptomyces is highly desirable. In this study, we developed a screening system for targeted gene knockout using a uracil auxotrophic host(Δpyr F) resistant to the highly toxic uracil analog of 5-fluoroorotic acid(5-FOA) converted by Pyr F, and a non-replicative vector p KC1132-pyr F carrying the complemented pyr F gene coding for orotidine-5'-phosphate decarboxylase. The pyr F gene acts as a positive selection and counterselection marker for recombinants during genetic modifications. Single-crossover homologous integration mutants were selected on minimal medium without uracil by reintroducing pyr F along with p KC1132-pyr F into the genome of the mutant Δpyr F at the targeted locus. Double-crossover recombinants were generated, from which the pyr F gene, plasmid backbone, and targeted gene were excised through homologous recombination exchange. These recombinants were rapidly screened by the counterselection agent, 5-FOA. We demonstrated the feasibility and advantage of using this pyr F-based screening system through deleting the otc R gene, which encodes the cluster-situated regulator that directly activates oxytetracycline biosynthesis in Streptomyces rimosus M4018. This system provides a new genetic tool for investigating the genetic characteristics of Streptomyces species. 相似文献
9.
We presented a wireless endoscope system developed on the embedded Linux platform. This wireless endoscope system consists of three parts： the endoscope capsule, the portable equipment and the image workstation, which make this system wireless and portable. Hardware design of this system and software design of the portable equipment are described. In clinical use, patients swallow the endoscope capsule for gastrointestinal inspection. The portable equipment receives images of gastrointestinal tract via the radio frequency module while it sets and reads back parameters of the capsule via the low frequency module. Acquired image data can be saved as a FAT32 format file in an universal serial bus disk. Images can be processed and reviewed at an Microsoft Windows PC workstation in the next stage. The image acquired by this wireless endoscope system is quite effective with clear details of gastrointestinal tract. However, the endoscope capsule was large, making it difficult to swallow. So the printed circuit board design of endoscope capsule needs to be improved. 相似文献
10.
There has not been life cycle assessment (LCA) software applicable to China's products. To faciliate the development of LCA software system in China, we built an object-oriented LCA software system plantform based on LCA international standards ISO 14040 to ISO 14043 and the commonness of diverse products. The system includes six modules: disassembly module, data collection module, arithmetic module, drawing module, database module and control module. It evaluates all economic and environmental impacts during the whole life cycle of a product. The integrated life cycle inventory database system allows dynamic expansion, which makes the effort required for data collection reduce with the increase of the system's application. With the improvement of human environmental-awareness, the demand of environment-friendly products is increasing, and ecological design of products has become a critical part in products development. Consummation of the LCA software system will provide a powerful tool for designing and developing Chinese ecological products. 相似文献
11.
目的：克隆蚓激酶基因并在GENEBANK中进行序列分析．方法：采用RT—PCR技术，以蚯蚓总．RNA为模板进行扩增，克隆蚓激酶基因、用Blast软件对基因进行同源性分析．结果：克隆了一个cDNA片段，与GENEBANK中蚓激酶基因序列最高同源性为99％．结论：本方法实用可行，同源性分析表明克隆的cDNA片段具备完整的蚓激酶编码区，为下一步进行蚓激酶的表达研究奠定了良好的基础． 相似文献
12.
本系统采用STC89C52RC单片机为主控芯片,JSY-MK-163单相互感计量模块为辅助,将开关电源提供的5V直流电压通过升压电路升压,再经过NE555芯片和滤波电路转换为一定频率输出的正弦交流电压信号,为待测RLC元器件提供测试信号源。单相互感计量模块通过其内部A/D对被测元件参数进行处理,通过MODBUS通信规约与单片机进行数据传输,单片机对数据进行处理和显示。实验表明:该简易测试系统具有响应速度快、显示稳定、测量精度高等优点,有较高的应用价值。 相似文献
13.
根据UPS原理,制作基于FPGA和单片机的24 V交流单相在线式UPS电源。系统主要由整流模块、蓄电池充电模块和逆变模块组成,以单片机和FPGA为核心,进行数据采样,控制输出SPWM波和反应动作控制,并具有过流保护、低压保护、电池电量检测等功能。电路总体结构简单,系统可靠性高,实用性强,能很好地实现持续供电功能,适用于中小型功率电路。 相似文献
14.
Transfection and expression of exogenous gene in laying hens oviduct in vitro and in vivo 总被引：2，自引：0，他引：2
Gao B Sun HC Song CY Wang ZY Chen Q Song HQ 《Journal of Zhejiang University. Science. B》2005,6(2):137-141
To examine whether or not the regulatory sequence of chicken ovalbumin gene can drive transgene expression specifically in hen oviduct, the authors constructed an oviduct-specific expression vector (pOV), containing 3.0 kilobases (kb) of the 5'-flanking sequence and 3.0 kb of the 3'-flanking sequence of the chicken 相似文献
15.
以NCBI中的EST数据库为主要数据来源,以一系列生物信息学软件为工具,进行了超氧化物歧化酶（SOD）基因的电子克隆及生物信息学分析。结果表明：通过电子克隆方法获得了SOD基因的编码区全长序列,该预测的SOD蛋白质氨基酸序列与数据库中同类基因的蛋白质氨基酸序列具有极高的相似性,并且含有完整的保守结构域;电子克隆到的SOD基因编码的不是分泌蛋白,也不是膜蛋白,而是胞质蛋白。通过某个基因的一个EST序列采用电子克隆的手段进行基因全长的电子拼接是可行的。 相似文献
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SoC芯片通常包含有复杂的数据通路,对复杂的数据通路的验证非常具有挑战性。无线通信SoC中包括很多功能模块,为了验证其复杂的数据通路的正确性,需要对每个功能模块进行模块级的验证。由于SoC验证已经成为整个流程中的重心,所以努力研发新的验证方法及设备,不断完善SoC验证计划和平台是当前的主要任务。以SD控制器和芯片系统(SoC)为例,探讨SoC模块级和系统级的验证,先确定验证策略并编写测试计划,再创建测试平台,最后对复杂的数据进行测试。 相似文献
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GPS定位数据采集器的设计与实现 总被引：1，自引：0，他引：1
给出了一种全球定位系统定位数据的采集模块,该模块能实时地采集定位载体的位置、速度等物理参量,并对其进行存储和再现;分析了GPS定位系统的基本定位原理,介绍了Fastrax iT rax02模块的特性、数据输出格式及其在本系统中的应用.该模块在设计过程中留有较多的扩展口,具有较好的扩展性. 相似文献
20.
微逆变器可实现独立的光伏模组最大功率点追踪控制,极大优化并网光伏发电系统的光伏能量转换,提供即插即用概念。光伏微逆变器在功率变换中,常采用高频变压器升压产生期望的输出交流电压,根据直流链配置可以分为直流链、伪直流链和无直流链3种微逆变器拓扑结构。微逆变器控制技术包括最大功率点追踪控制技术、输出电流控制技术、孤岛效应侦测与保证技术等,且功率开关对于改善微逆变器的转换效率至关重要。 相似文献