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971.
如何做好合并高校档案管理工作,整合合并高校的档案资源,建立统一的档案管理制度和模式,提高档案管理工作人员的素质,发挥档案资源的价值,为合并高校实现快速协调的持续发展服务,是档案管理工作者值得认真思考的问题. 相似文献
972.
Event-related potentials (ERPs) were measured to investigate the executive inhibitory processes in mental arithmetic. Subjects had to compute arithmetic expressions visually presented in four chunks. ERP analyses were conducted for the second chunk comparing the “NoCalculate” to the “Calculate” conditions. In the Calculate condition subjects could compute intermediate results. In the NoCalculate condition subjects had to withhold the computation. The results showed a negative effect (N380) over frontocentral regions at about 380 ms, probably reflecting the calculation inhibition demand in the NoCalculate condition. In addition, the dN380 (NoCalculate-Calculate difference) was more pronounced in the right hemisphere, which is consistent with the findings of previous fMRI and PET studies that the right prefrontal cortex is closely associated with response inhibition. The results support the generalization of the frontocentral N2 as a neurobehavioral tool for investigating inhibitory executive control. 相似文献
973.
Gas vesicles provide buoyancy to Microcystis and other common cyanobacterial bloom-forming species. gvpA and gvpC are structural genes encoding gas vesicle proteins. Phylogenetic analyses of 10 Microcystis strains/uncultured samples showed that gvpC and each intergenic segment of the gvpA-gvpC region can be divided into two types. The combination of different types of gvpC and intergenic segments is an important factor that diversifies this genomic region. Some Microcystis strains isolated in China possess a 172 to 176 bp sequence tag in the intergenic segment between gvpA and gvpC. The gvpA-gvpC region in Microcystis can be divided into at least 4 classes and more numbers of subclasses. Compared to rbcLX and other regions, the high variability of the gvpA-gvpC region should be more useful in identifying geographical isolates or ecotypes of Microcystis. 相似文献
974.
Ultrashort lasers have become powerful tools by inducing extremely nonlinear effects in a wide variety of materials. Femtosecond laser data storage in non-photosensitive media is promising for its high density and fast retrieval.We reviewed the progress of three types of femtosecond laser storage in transparent materials:three-dimensional bit-oriented storage by micro-voids,holographic data storage by two beam interference and storage by computer-generated holograms. 相似文献
975.
易鸿 《渝西学院学报(自然科学版)》2007,(6):66-68
提出小波分析对信号奇异性的检测方法,实现小波分析对信号各类奇异间断点的有效检测,并结合仿真实例对小波分析在奇异信号检测上的应用进行实际分析. 相似文献
976.
以60名非英语专业学生的作文为样本,通过统计分析作文中出现的词汇错误,试图解决三个问题:(1)确认学生在写作中所犯词汇错误类型及比例;(2)分析主要错误来源;(3)评估词汇错误的严重程度。结果表明,学生的词汇错误主要集中在词义混淆和词汇搭配。因此,笔者建议在教学中尝试利用语料库以及词汇法教学等手段,提高学生在写作中英语词汇运用的准确性与流利性。 相似文献
977.
WU Song CHEN Hong GU JiaHua YU HongRut 《科学通报(英文版)》2007,52(17):2305-2309
This study deals with the sources of signal distortion of a piezoelectric transducer heated by measured gas flow. These signal distortions originate from both unloading of preload on a piezocrystal because of expansion of a diaphragm in the test apparatus and the pyroelectric effect of a heated piezoelectric crystal. A plastic film on the diaphragm of the transducer can effectively insulate the diaphragm and the piezocrystal within transducer from heating by gas flow, eliminating the sources of distortion. A method for evaluating the thickness of the film is proposed. 相似文献
978.
输出假设理论认为,产出使学习者从理解中的“语义处理”转换到二语开发不可或缺的“句法处理”。深入分析输出假设的心理语言机制,对二语习得具有指导作用。 相似文献
979.
A multi-sensory five-fingered prosthetic hand has been designed on the basis of underactuated mechanism and coupling principle. The hand is much similar to the adult hand. Three motors actuate the thumb, the index finger and the other three fingers each. The hand comprises 13 joints. Actuated by a motor, the thumb can move along a conic surface, which is superior in appearance. Driven by another motor with springs as transmission elements, the mid finger, ring finger and little finger can envelop objects with complex shape. The sensory system and the appearance design are introduced. It was verified by experiments that the hand has strong capacity of self adaptation and can accomplish accurate and powerful grasp for objects with complex shape. 相似文献
980.
两种新型石油磺酸盐基复合驱油剂的研制 总被引:1,自引:0,他引:1
为提高驱油剂降低油水界面张力的能力,提高原油的采收率,在研究了石油磺酸盐表面活性剂表面活性的基础上,研制了改性纳米二氧化硅-石油磺酸盐和磺酸盐型Gemini-石油磺酸盐两种复合驱油剂,采用TX-500界面张力仪考察了两种复合驱油剂降低胜利油田油水界面张力的能力。研究表明,在一定的浓度条件下,石油磺酸盐能降低油水界面张力至1×10-2mN.m-1,改性纳米二氧化硅-石油磺酸盐复合驱油剂能降低油水界面张力至3.2×10-3mN.m-1,磺酸盐型Gemini-石油磺酸盐复合驱油剂能降低油水界面张力至(4~6)×10-4mN.m-1。与传统驱油剂相比,两种复合驱油剂降低油水界面张力的能力显著提高。 相似文献