Design and Implementation of Instant Messenger Based on DES and RSA HybridEncryption

随着计算机网络和移动互联网的发展，即时通信系统（InstantMessenger，即IM）在人们生活工作中扮演着越来越重要的角色，政府、企业都需要使用即时通信软件来提高工作效率，降低运作成本。最早的即时通信软件能够实现互联网、局域网内的信息沟通、文件传输等功能。随着时代的发展，即时通信软件的功能越来越丰富，可以进行语音、视频聊天，群聊天以及分享心情等等。但是对软件安全性能的关注并没有跟上，用户信息遭到泄露，对即时通信行业造成不良影响，应引起我们的重视。不少企业开始加强对即时通信安全性的研究和开发。本论文就是着眼于此，对安全的IM系统进行设计与实现，以供学习借鉴。 论文主要介绍了即时通信系统的...With the development of computer and Internet, Instant Messenger (IM) plays an increasingly important role in people's lives. The government and enterprises need Instant Messenger to improve work efficiency and reduce costs. The earliest Instant Messenger can connect to the Internet, support information communication, file transfer and other functions. As time flows, IM got more and more functions...学位：工学硕士院系专业：软件学院_工程硕士(软件工程)学号：X201423000

The Approach For Mechanism Research Of TCM Single Prescription’s ADR

中药不良反应的预测与机理研究已经成为当前药物研究中的一个热点，然而目前却没有一种有效的方法能在分子机制上对中药不良反应进行预测并阐明其机理，本文进行的是相关方法论方面的研究。本文选取了8种常见中药单方作为研究对象，以鸦胆子为例子进行深入研究分析。本文采用的不良反应预测方法是通过计算机辅助小分子潜在靶点搜寻的方法，寻找鸦胆子各化学组分对应的不良反应相关蛋白，利用不良反应相关蛋白来预测其对应的不良反应。通过将预测结果与实际文献中报道的不良反应进行对比来评估预测结果的准确性。文献报道的28个实际不良反应中的26个都能通过该方法得到有效预测，预测结果的准确率达92.9%。通过寻找鸦胆子所重点作用代谢路...Adverse Drug Reaction(ADR) of Traditional Chinese Medicine (TCM) draws more and more attention in the world. However, current knowledge and methodology for TCM ADR research still remain inefficient and limited. In this work, a new computer-aided approach was introduced to explore molecular mechanisms underlying TCM induced ADR using a traditional herb Yadanzi (Brucea javanica (L.) Merr) as example...学位：理学硕士院系专业：生命科学学院生物学系_细胞生物学学号：2162007115421

Study on the Closed-Loop Driving & Detecting Interface Circuit for Resonant Pressure Sensor

谐振式微机械压力传感器具有尺寸小、精度高、稳定性好、易与数字电路接口等优点，在压力检测领域有着广阔的应用前景。精确测量是谐振式微机械压力传感器研究的目标，驱动检测电路的性能优劣直接影响整体器件测量效果，本论文主要针对谐振式微机械压力传感器驱动检测电路展开研究。 论文首先简单回顾了MEMS技术及压力传感器的分类，对谐振式压力传感器的激励方式及接口电路做了简要介绍；其次分析了微机械谐振式压力传感器的结构和工作原理，比较了不同的变电容检测方式，并讨论了各自的优缺点；在此基础上，理论分析了谐振式压力传感器基于AGC控制技术和基于PLL控制技术的两种闭环驱动方式的基本原理和运行特性，通过建立传感器与驱...Resonant micro-mechanical pressure sensor has many advantages such as the small size, high precision, good stability and compatibility to digital circuit, so it has a broad application prospect in the field of pressure testing. Accurate measurement is the goal of the study to the resonant micro mechanical pressure sensor. The performance of the driving and detecting circuit has a direct influence ...学位：工学硕士院系专业：物理与机电工程学院_机械工程学号：1992010115274

Empirical Research on Chinese Banking System: Macroeconomic Credit Risk Stress-Testing

作为压力测试方法在宏观经济分析中的运用，宏观压力测试应运而生。随着各国金融监管当局对金融风险的日益重视，宏观压力测试逐渐成为检验一国金融体系脆弱性的首选工具。本文的研究目的就是为了探索我国银行体系信贷违约率与宏观经济因素之间的关系，并在此基础上运用宏观压力测试评估我国银行体系的抗风险能力。 本文在借鉴和分析国外成熟模型的基础上，构建了适合我国经济环境的宏观压力测试模型。首先使用Logit变换和一阶差分将不良贷款比率转化为“不良贷款指标”〖∆y〗_t，以指标〖∆y〗_t作为因变量与宏观经济因素进行多元线性回归分析，尽可能使这一指标能够充分反映各宏观经济指标所提供的信息。...As stress-testing in the use of macroeconomic analysis, macroeconomic stress tests came into being. Since the authorities take importance to the financial risk, macroeconomic stress-testing is becoming the first choice to test the vulnerability of a country's financial system. The purpose of this paper is to explore the relationship between the credit default rates of Chinese banking system and ma...学位：经济学硕士院系专业：经济学院金融系_投资学学号：1562007115149

Experimental Boosting of the Oxygen Reduction Activity of an Fe/N/C Catalyst by Sulfur Doping and Density Functional Theory Calculations

向Fe/N/C非贵金属催化剂中再引入S掺杂是进一步提高其氧还原催化活性的有效方法。为了探究活性提高的原因,本文以三聚氰胺-甲醛树脂为前驱体,氯化; 钙为模板,氯化铁为铁源,通过添加硫氰化钾(KSCN)来控制热解催化剂的S掺杂量。通过对比分析催化剂的物化性质,结合密度泛函理论(DFT)计算,分; 析S掺杂促进Fe/N/C催化剂氧还原活性的原因。透射电子显微镜(TEM)和N_2吸脱附等温线测试结果表明,S元素可抑制含铁纳米粒子的形成,促使形; 成多孔碳结构,提高比表面积。X射线光电子能谱(XPS)结果表明,适量S前驱体可实现较高的S掺杂含量,得到最优的活性,过量的S反而会导致Fe和S的; 掺杂量同时降低,影响活性。DFT计算结果表明在Fe-N_4大环中引入S掺杂,可增强O_2分子和中间体OOH与Fe-N_4结构中的Fe的相互作用,; 促进形成Fe―O键,从而导致O―O键的键能显著降低,为后续反应O―O键的断裂提供可能,促进ORR反应的进行。S doping in Fe/N/C non-precious metal catalysts is an effective approach to further improve their catalytic activity for the oxygen reduction reaction (ORR). However, the enhancement mechanism is not yet clear. Here, we synthesized an Fe/N/C catalyst using melamine-formaldehyde resin as the N and C precursors, CaCl2 as the template, and FeCl3 as the Fe precursor. The effects of S doping on the morphology, textural property, composition, and ORR catalytic activity were investigated by adding various amounts of KSCN as a precursor. Transmission electron microscopy (TEM) and N-2 adsorption-desorption isotherm results revealed that S prevented the growth of Fe-containing nanoparticles, and facilitated the formation of a porous structure, which increased both the catalyst surface area and mass transfer rate. X-ray photoelectron spectroscopy (XPS) results indicated that a suitable amount of S precursor led to a high doping level of S and provided the highest ORR activity. However, too much S in the precursor decreased the doping levels of both Fe and S, due to the formation of FeS, which could be completely removed by acid leaching. Density functional theory (DFT) calculations showed that the addition of S in an Fe-N-4 macrocycle could enhance the interaction strength of the Fe-O bond between the O-2 molecule or the intermediate OOHspecies and Fe in the Fe-N-4 structure, resulting in a significant decrease in the O-O bond energy, and may help in bond breaking in subsequent reactions, facilitating the ORR process.National Natural Science Foundation of China [21373175, 21621091

基于AGC闭环控制的谐振式压力传感器驱动仿真及接口电路设计

谐振式压力传感器利用正反馈原理,构成包括机械谐振子在内的机电一体的高品质闭环谐振系统,闭环拓扑结构对保持机械谐振器振荡的稳定性和可靠性起着重要作用。本文针对一种典型结构的静电驱动电容检测谐振式压力传感器,在分析工作原理的基础上,构建了其行为级闭环自激仿真模型,在MATlAb中对自激回路的起振情况进行了仿真;最后设计了基于AgC的闭环控制电路。he theory of positive feedback is used by resonant pressure sensor to form highquality mechanical and electrical integration close-loop resonant system including mechanical harmonic oscillator,closed loop topology structure plays an important role to keep the stability and reliability of the mechanical resonator oscillation.In this paper,a kind of typical structure of the electrostatic drive and capacitance detection resonant pressure sensor is analyzed.The behavior model of the closed-loop simulation of self-excitation is constructed based on analyzing the working principle,excitation circuit of the oscillation starting are simulated using MATLAB.Finally,the closed-loop control circuit based on AGC is designed

从外籍学生角度看大陆高校对外籍学生的管理——以厦门大学为主,兼与台湾高校对比

作者简介：郑晓，厦门大学人文学院人类学与民族学系2010级本科生；涨驰，厦门大学人文学院中文系2010级本科生；浏畅，厦门大学人文学院中文系2010级本科生；吴院琴，厦门大学人文学院人类学与民族学系2010级本科生。大陆高校对外籍学生的管理,是自新中国成立以来,特别是改革开放以来,我国教育事业面临的一个新课题。外籍学生的不断增多,一方面代表我国文化教育事业的蓬勃发展,另一方面,也使大陆高校在学生管理上面临更多挑战。本文选取有"南方之强"之称的厦门大学作为范例,采用文化人类学半结构式访谈的方法,对大陆高校在外籍学生管理方面遇到的困难进行分析,并提出相关对策。此外,本文在保持相对客观的基础上,还注重从外籍学生的视角进行观察和思考,并与台湾的相关高校进行对比,以期能够总结出一套更加有效、人性的管理模式

基于矢量螺旋推进舵的新型主动式减摇装置的仿真研究

本文介绍了一种基于矢量螺旋推进舵的主动式船舶减摇装置,并在分析随机海浪的波能谱和波倾角以及船舶运动受力的基础上,建立了随机海浪的仿真模型,利用Matlab对海浪波倾角及有无减摇装置的船舶横摇运动进行了建模及仿真研究,研究表明该减摇装置具有可控性强、易改装的特点,能够提高船舶的耐波性。福建省海洋高新产业发展专项资金项目[2016]13

Oxidative dehydrogenation of ethane to ethylene in the presence of HCl over CeO_2-based catalysts

报道了一种HCl存在时温和条件下的乙烷氧化脱氢制乙烯催化转化新途径.研究发现,在多种金属氧化物催化剂中,CEO2呈现最佳乙烯生成的催化性能.与纳米粒子相比,具有棒状和立方体状形貌的CEO2纳米晶具有较高的乙烷转化率和乙烯选择性.以MnOX修饰CEO2可进一步提高催化性能.在8 WT%MnOX-CEO2催化剂上,723 k反应2 H时乙烷转化率和乙烯选择性分别为94%和69%.该催化剂性能稳定,反应100 H乙烯收率可保持在65%–70%.HCl的存在对乙烯的选择性生成起着至关重要的作用,一部分乙烯来自于氯乙烷的脱HCl反应.This article reports a new catalytic route for the oxidative dehydrogenation of ethane to ethylene in the presence of HCl at moderate temperatures.CeO2 was found to be the most efficient catalyst for the production of ethylene from the variety of metal oxides examined in this work.CeO2 nanocrys‐tals with rod and cube morphologies showed higher ethane conversions and ethylene selectivities than CeO2 nanoparticles.The modification of CeO2 by MnOx further enhanced the catalytic perfor‐mance.Ethane conversion of 94% and ethylene selectivity of 69% were obtained after 2 h of reac‐tion at 723 K over an 8 wt% MnOx-CeO2 catalyst.This catalyst was stable and the ethylene yield could be sustained at 65%–70% over 100 h of reaction.The presence of HCl played a key role in the selective production of C2H4, and some of the C2H4 was probably formed from chloroethane by de‐hydrochlorination.supportedbytheNationalBasicResearchProgramofChina(973Program;2010CB732303); theNationalNaturalScienceFoundationofChina(21033006); theProgramforChangjiangScholarsandInnovativeResearchTeaminUniversity(IRT1036)~

矢量减摇装置及其控制系统设计

为实现船舶减摇系统的灵活性、快速响应特性、高效率、强环境适应性的要求,在水下矢量螺旋桨推进器的基础上,提出了一种基于二元矢量螺旋桨的主动矢量减摇装置。首先对该装置的结构设计方法进行了阐述,对螺旋桨推力进行了评估,并通过搭建基于组合导航系统的姿态检测模块,对船体姿态自平衡控制系统方案进行了设计。通过滑台重物往复移动模拟横摇激励,利用船模进行了零航速下的模拟减摇试验,并对该种减摇装置的特点进行了总结。福建省海洋高新产业发展专项资金项目[2016]13