The Application and Research of Computer Network Virtual Experimental Teaching System Based on B/S Framework

随着时代的发展，虚拟教学作为一种新的教学模式己经得到越来越广泛地应用。其中虚拟实验教学已成为近年来研究的重点和难点。传统教学实验难以通过增加设备、扩大实验室规模来满足迅速膨胀的学生规模，而虚拟实验是解决这一问题的有效途径。虚拟实验是指借助于多媒体、仿真和虚拟现实等技术在计算机上营造可辅助、部分替代甚至全部替代传统实验各操作环节的相关软硬件操作环境，实验者可以像在真实的环境中一样完成各种实验项目，所取得的实验效果等价于甚至优于在真实环境中所取得的效果。 实验课程在培养和提高学生动手实践能力、观察能力、理论联系实际能力等方面有着不可替代的作用，实验课程也为学生的研究能力、开拓能力、创新意识等综合...As the times develop, virtual teaching, the new teaching model, has been widely used recently. The virtual experiment teaching has become the important and difficult part to study in recent years. It’s difficult for traditional teaching experiment to satisfy the rapidly increasing number of students by increasing the teaching equipments and expanding the scale of labs, while virtual experiment is ...学位：工程硕士院系专业：软件学院_工程硕士(软件工程)学号：X200923010

助人者成长与职业倦怠

社会工作对于缓解社会矛盾、构建和谐社会具有重大意义,社会的发展越来越离不开社会工作人才,社工人才队伍的建设引起了全社会的关注。然而,社会工作是一项用生命影响生命的情感性工作,它的这种特殊性使得社会工作者面临着严重的职业倦怠问题,很多社会工作者工作了短短几年就离开岗位,造成社工人才的缺失。社会工作者产生职业倦怠的原因主要包括社会和自身两方面,本文着重从社会工作者自身成长的角度分析了产生职业倦怠问题的原因,并提出了相应的解决对策

关于农民工子女教育公平问题的思考

随着社会主义市场经济的发展和城市化进程的不断加快,越来越多的农民工进入了城市,他们成为城市建设的重要力量。然而,农民工在城市中的生活状况不容乐观,尤其是农民工子女的教育问题难以解决。农民工子女的教育问题必须得到有效解决,它是教育公平的重要体现,是提高国民素质的关键,也是社会和谐稳定的有力保障。本文着重阐述了学习资源缺乏、公立学校排斥和家庭环境对农民工子女的影响,从微观层面来分析农民工子女教育问题难以解决的原因,针对原因尝试通过构建农民工子女的社会支持网络来解决问题

Cash Flow Volatility and Liquidity Risk——Evidence from Chinese Open-end Funds Market

开放式基金是我国资本市场上的重要组成部分，最主要特点就是其自由申赎的机制。这无疑是一把“双刃剑”，一方面为投资者提供了“收益-流动性”兼顾的投资方式，另一方面却大大的增加了开放式基金的流动性风险。因此，开放式基金管理者是否能够预测到投资者的申赎行为，并据此调整基金资产组合的流动性就成为了值得研究的课题。本文从我国开放式基金的现状分析入手，运用国外文献中较为普及的资金流量法计算出基金面临的现金流波动，并通过使用价量结合的Amihud法、BDSSL-VaR两类指标测算了我国开放式基金市场上所有披露重仓股信息的基金资产组合流动性，继而使用固定效应面板回归技术分析了基金管理者在面对现金流波动时将如何调...Open-end fund is an important part of domestic capital market, which allows free subscription and redemption. This is no doubt a double-edged sword. Although it provides investors with methods that balance return and liquidity, the liquidity risk is significantly increased at the same time. Thus, whether open-end fund managers can forecast behavior of subscription and redemption and adjust their p...学位：经济学硕士院系专业：王亚南经济研究院_金融学(含保险学)学号：2772010115265

Determination for the Contents of Neu5Ac, Neu5Gc and KDN in Organ Meats and Muscle of Pigs by LC-MS/MS

目的：建立液相色谱-三重四级杆质谱联用法（LC-MS/MS）测定猪内脏和肌肉组织中唾液酸N-乙酰神经氨酸（Neu5Ac）、N-羟乙酰神经氨酸（Neu5Gc）和脱氨神经氨酸（KDN）浓度的分析方法。方法：将内脏肉组织匀浆后,利用三氟乙酸（TFA）将结合态的唾液酸从糖脂或糖蛋白链上解离下来后进样分析。色谱条件：色谱柱为ZORBAX Eclipse Plus C18（5μm,4.6×250 mm,Waters）,流动相为0.1%醋酸铵-100%乙腈（9：1）,柱温：25℃,流速800μL·min~（-1）,进样量20μL。质谱条件：离子源为电喷雾化离子源（ESI）,扫描方式为多重反应监测（MRM）,监测离子对：Neu5Ac：307.7→87.0,Neu5Gc：323.3→116.0,KDN：266.7→87.0,13C3Neu5Ac内标品：310.9→90.0。结果：Neu5Ac、Neu5Gc和KDN分别在0.1~20.0、0.05~10.00和0.005~1.000μmol·L~（-1）的浓度范围内和对照品与内标峰面积比值线性关系良好,重复性平均RSD为1.2%,稳定性平均RSD为1.9%,日间和日内精密度试验RSD均小于6.7%,平均回收率为92.9~106.4%。结论：本方法简便、快速、灵敏度高,可广泛运用于组织和体液中唾液酸的测定。Objective： To establish an LC-MS/MS method for the detection of N-acetylneuraminic acid（Neu5Ac）,N-glycolylneuraminic acid（Neu5Gc） and 2-keto-3-deoxy-D-glycero-D-galactonononic acid（KDN） in organ meats and muscle of pigs.Methods： Tissues were acid hydrolyzed with trifluoroacetic acid（TFA） to get ganglioside-bound and glycoprotein-bound sialic acid,followed by injected and analyzed. The analysis was performed on an ZORBAX Eclipse Plus C18（5 μm, 4.6 ×250 mm, Waters）column, and the mobile phase consisted of 0.1 % ammonium~-100 % acetonitrile（9：1）, the flow rate was 800 μL/min, the temperature was maintained at 25 ℃, injection volume was set up 20 μL. Negative electrospray ionization（ESI） and multiple reaction monitoring（MRM） mode was used, MRM： Neu5Ac： 307.7→87.0, Neu5Gc： 323.3 →116.0, KDN： 266.7→87.0, 13C3Neu5Ac（IS）： 310.9→90.0.Results： The ratio of internal with standard sample peak area and content of Neu5 Ac, Neu5 Gc and KDN showed good linearity in the range of 0.1~20.0, 0.05~10.00, and 0.005~1.000 μmol/L, RSDs of the repeatability and stability were 1.2 % and 1.9 %, Intra-and inter-day RSDs were all lower than 6.7%, the recoveries of sialic acid were 92.9~106.4%. Conclusion： The established method is simple,accurate and rapid, higher sensitivity and can be applied to determination of Neu5 Gc, Neu5 Ac and KDN in tissues and fluid of animals and human.国家自然科学基金项目（31271038

Effects of nutrient limitation on cell cycle,toxin content and composition of Alexandrium tamarense CI01

优化了塔玛亚历山大藻AlEXAndrIuM TAMArEnSE CI01细胞同步化方法,研究了n、P限制对A.TAMArEnSE CI01细胞周期及毒素含量和组成变化的影响。结果表明,采用前期驯化、细胞沉降分离和光限制诱导相结合的同步化方法,细胞同步率提高了约14%。n、P限制条件下,细胞分裂受抑制,分别停滞于g2/M期和g1期。营养盐对毒素合成及组成影响比较明显:n限制下单细胞毒素含量降低,P限制下单细胞毒素含量升高。在正常营养和P限制条件下,C1,2占毒素总量的98%以上,gTX2,3占总毒素量的2%左右;n限制条件下,C1,2所占比例下降到90%左右,而gTX2,3比例增长到约10%。根据C1,2和gTX2,3在一个细胞周期内的变化规律推测,毒素的合成受光诱导并在细胞周期g1期的特定时间内合成,细胞可能先合成gTX2,3毒素,后被转化为C1,2毒素。This study optimized the cell synchronized method of Alexandrium tamarense CI01 and investigated the effects of nutrient limitation on cell cycle,toxin content and composition of A.tamarense CI01.The result showed that the synchronization ratio of A.tamarense CI01 cells increased 14% compared to the traditional darkness induced method.Under nutrient limitation conditions,nitrate-limited cells were arrested at G2/M phase while phosphate-limited cells were arrested at G1 phase.Toxin content and composition of A.tamarense CI01 varied significantly at the different cell cycle phases.Nitrate-limitation decreased toxin content while phosphate-limitation increased toxin content compared to the nutrient replete condition.Compared to nutrient replete and phosphate-limitation conditions,the ratio of C1,2 declined from 98% to 90%,and the ratio of GTX2,3 increased from 2% to 10% under nitrate-limitation.Toxin biosynthesis was induced by light and always occurred during a defined time frame within the G1 phase of the cell cycle.Analyzing toxin biosynthesis time and ratios of C1,2 and GTX2,3 toxins in cells,we postulate that GTX2,3 is synthesized firstly and then is transferred to C1,2 in A.tamarense CI01.国家自然科学基金(40776068;40876059

税务机关与企业:零和博弈还是互助共赢?——基于上市公司信息披露质量视角的研究

从税收征管对上市公司信息披露质量的影响这一视角出发,探讨税务机关与企业间的关系。研究发现:税收征管力度越高的地区,企业的信息披露质量越高。税收征管的这种影响因企业产权性质的差异而有所不同。税收征管能够显著改善民营企业的信息披露质量,但对国有企业的影响并不明显。政企关系、社会资本等"关系机制"的存在会显著削弱税收征管的作用。国家自然科学基金面上项目(71772155);国家自然科学基金面上项目(71572158);国家自然科学基金青年项目(71803204

Advance in research of water-proof liquid band-aid

创可贴是人们生活中最常用的外科用药。传统的创可贴即是一长形胶布,中间附以浸过药物的纱布,从而起保护伤口,暂时止血的作用。传统创可贴适合创伤较为表浅,伤口整齐干净、出血不多而又不需要缝合的小伤口使用。本文所要讲述的液体创可贴可用于大部分的外伤伤口,能够及时止血及防止病原微生物的感染。本文主要讲述了近些年刚刚出现的防水型液体创可贴,包括其主要的作用,材料组成及相关临床研究。Band-aid is the most commonly used surgical medication. The traditional band-aid is a longshaped adhesive,and the intermediate layer accompanied by soaking medicine gauze,thereby used for the wound and temporary hemostasis. The traditional band-aid is suitable for shallow trauma,small wound,clean and tidy wound,less bleeding and the wound that needs no suture. In this article we introduced a liquid band-aid that can be used for most of the traumatic wound,can timely stop bleeding and prevent microbial infection. We mainly described the waterproof liquid band-aid appeared in recent years,including its main effects,material composition and related clinical research