社会性网络服务的特点及其对企业竞争情报工作的影响   总被引：2，自引：0，他引：2  

秦铁辉  桑晓琦 《图书情报知识》2007,33(6):11-15

当前,互联网已成为企业竞争情报工作的重要阵地,人际网络在整个情报循环中的作用已受到相当程度的重视。本文从当前网络热点社会性网络服务(SNS)入手,分析了基于SNS构建的人际网络特点,对由此引发的企业竞争情报工作的变革进行了探讨,重点分析了社会性网络服务对企业竞争情报收集内容及方式的影响。  相似文献   

论图书馆管理的人本主义价值取向   总被引：17，自引：0，他引：17  

桑晓东  宋书星 《图书情报工作》2003,46(9):40-44

在科学管理与人本管理比较的基础上,提出图书馆应坚持科学管理与人本管理、科学精神与人文精神相统一;并简要分析现行图书馆规章制度的缺失及其修订完善所应遵循的基本原则。指出,管理体制“软件”现代化是图书馆现代化建设不容忽视的重要内容。  相似文献   

衰老自由基学说和运动对抗自由基损伤的作用   总被引：2，自引：0，他引：2  

桑琛  李明学 《吉林体育学院学报》2007,23(1):80-81,140

从自由基的产生、清除以及对机体的损害作用几方面概述了衰老的自由基学说.并说明运动对机体自由基的产生和清除随运动方式、运动强度、运动时间的不同而产生相反的效应,指出长期的有氧运动可以抑制自由基的产生并提高机体的抗氧化能力,对延缓衰老有着不可忽视的作用.  相似文献   

中国成人教育之“根”：社区成人教育？——与南海先生“社区说”商榷     

桑宁霞 《河北大学成人教育学院学报》2008,10(2):5-7

针对南海先生提出的“中国成人教育之‘根’：社区成人教育”，本文提出质疑。笔者认为原文在概念厘定、宏观把握、未来预测等方面都存在不同程度的遗憾，特与作者商榷，以推动学术进步。  相似文献   

Centrifugal multiplexing fixed-volume dispenser on a plastic lab-on-a-disk for parallel biochemical single-end-point assays     

Moonwoo La  Sang Min Park  Dong Sung Kim 《Biomicrofluidics》2015,9(1)

In this study, a multiple sample dispenser for precisely metered fixed volumes was successfully designed, fabricated, and fully characterized on a plastic centrifugal lab-on-a-disk (LOD) for parallel biochemical single-end-point assays. The dispenser, namely, a centrifugal multiplexing fixed-volume dispenser (C-MUFID) was designed with microfluidic structures based on the theoretical modeling about a centrifugal circumferential filling flow. The designed LODs were fabricated with a polystyrene substrate through micromachining and they were thermally bonded with a flat substrate. Furthermore, six parallel metering and dispensing assays were conducted at the same fixed-volume (1.27 μl) with a relative variation of ±0.02 μl. Moreover, the samples were metered and dispensed at different sub-volumes. To visualize the metering and dispensing performances, the C-MUFID was integrated with a serpentine micromixer during parallel centrifugal mixing tests. Parallel biochemical single-end-point assays were successfully conducted on the developed LOD using a standard serum with albumin, glucose, and total protein reagents. The developed LOD could be widely applied to various biochemical single-end-point assays which require different volume ratios of the sample and reagent by controlling the design of the C-MUFID. The proposed LOD is feasible for point-of-care diagnostics because of its mass-producible structures, reliable metering/dispensing performance, and parallel biochemical single-end-point assays, which can identify numerous biochemical.  相似文献   

Structural design of a double-layered porous hydrogel for effective mass transport     

Hyejeong Kim  Hyeon Jeong Kim  Hyung Kyu Huh  Hyung Ju Hwang  Sang Joon Lee 《Biomicrofluidics》2015,9(2)

Mass transport in porous materials is universal in nature, and its worth attracts great attention in many engineering applications. Plant leaves, which work as natural hydraulic pumps for water uptake, have evolved to have the morphological structure for fast water transport to compensate large water loss by leaf transpiration. In this study, we tried to deduce the advantageous structural features of plant leaves for practical applications. Inspired by the tissue organization of the hydraulic pathways in plant leaves, analogous double-layered porous models were fabricated using agarose hydrogel. Solute transport through the hydrogel models with different thickness ratios of the two layers was experimentally observed. In addition, numerical simulation and theoretical analysis were carried out with varying porosity and thickness ratio to investigate the effect of structural factors on mass transport ability. A simple parametric study was also conducted to examine unveiled relations between structural factors. As a result, the porosity and thickness ratio of the two layers are found to govern the mass transport ability in double-layered porous materials. The hydrogel models with widely dispersed pores at a fixed porosity, i.e., close to a homogeneously porous structure, are mostly turned out to exhibit fast mass transport. The present results would provide a new framework for fundamental design of various porous structures for effective mass transport.  相似文献   

An unexpected particle oscillation for electrophoresis in viscoelastic fluids through a microchannel constriction     

Xinyu Lu  Saurin Patel  Meng Zhang  Sang Woo Joo  Shizhi Qian  Amod Ogale  Xiangchun Xuan 《Biomicrofluidics》2014,8(2)

Electrophoresis plays an important role in many applications, which, however, has so far been extensively studied in Newtonian fluids only. This work presents the first experimental investigation of particle electrophoresis in viscoelastic polyethylene oxide (PEO) solutions through a microchannel constriction under pure DC electric fields. An oscillatory particle motion is observed in the constriction region, which is distinctly different from the particle behavior in a polymer-free Newtonian fluid. This stream-wise particle oscillation continues until a sufficient number of particles form a chain to pass through the constriction completely. It is speculated that such an unexpected particle oscillating phenomenon is a consequence of the competition between electrokinetic force and viscoelastic force induced in the constriction. The electric field magnitude, particle size, and PEO concentration are all found to positively affect this viscoelasticity-related particle oscillation due to their respective influences on the two forces.  相似文献   

Study for optical manipulation of a surfactant-covered droplet using lattice Boltzmann method     

Se Bin Choi  Sasidhar Kondaraju  Joon Sang Lee 《Biomicrofluidics》2014,8(2)

In this study, we simulated deformation and surfactant distribution on the interface of a surfactant-covered droplet using optical tweezers as an external source. Two optical forces attracted a single droplet from the center to both sides. This resulted in an elliptical shape deformation. The droplet deformation was characterized as the change of the magnitudes of surface tension and optical force. In this process, a non-linear relationship among deformation, surface tension, and optical forces was observed. The change in the local surfactant concentration resulting from the application of optical forces was also analyzed and compared with the concentration of surfactants subjected to an extensional flow. Under the optical force influence, the surfactant molecules were concentrated at the droplet equator, which is totally opposite to the surfactants behavior under extensional flow, where the molecules were concentrated at the poles. Lastly, the quasi-equilibrium surfactant distribution was obtained by combining the effects of the optical forces with the extensional flow. All simulations were executed by the lattice Boltzmann method which is a powerful tool for solving micro-scale problems.  相似文献   

发酵工程实验教改     

胡翠英  李良智  扶教龙  姚雪梅 《科教文汇》2014,(28):63-64

发酵工程实验是一门实践性、应用性课程,这门课程的讲授目的应该是为社会培养具有独立分析问题、解决问题能力的专业人才。文中在分析发酵实验现有问题的基础上,提出发酵相关实验的教学改革：以社会需求为目标,发挥学生学习积极性,调整发酵实验项目和实践体系,改进课程成绩评定方式等。  相似文献   

The Impact of the Teleoaffective Structure of Undergraduate Teach- ing Practices on Students' Information Access: Exploration and Reflection from a Case Study北大核心     

于良芝  刘鸿彬  杨天德 《中国图书馆学报》2023,49(5):26-43

世界高等教育机构普遍认为，信息的获取与利用对人才培养不可或缺，而有关学生信息行为的研究却一再显示，当代大学生对信息的获取与利用存在缺陷。至于为什么人才培养必须依赖信息获取，何为充分的信息获取，如何保证充分的信息获取，学术界少有系统的理论阐释。本研究旨在通过考察学生信息获取与教学实践的关系，探索上述问题的答案。借鉴实践理论的“目的情感结构”概念，以一所大学的某实体学院本科教学实践为案例，通过政策文本、访谈、问卷调研等方式，收集有关案例学院本科教学的数据；将这些数据按归纳思路予以分析，分别得出了该院本科教学的目的目标、讲授任务、学习任务、信息获取驱动；然后依据“目的情感结构”概念的框架，将归纳结果整合为案例学院本科教学的目的情感结构，展现并反思嵌入其中的信息获取动力机制。研究结果显示，特定教学实践的目的情感结构通过嵌入特定的信息获取驱动，影响甚至塑造学生的信息获取；但只有注重知识理解的教学实践，才能凸显信息对人才培养的价值，进而指导教师设计合理的信息获取驱动，提升学生的信息获取与利用。图3。表3。参考文献56。  相似文献