APP软件性能效率研究

性能效率是APP软件的重要质量属性，但目前缺乏APP软件性能效率的通用模型。分析了APP软件的性能特征，基于ISO/IEC 25010标准提出了APP软件的性能效率模型，定义了APP软件性能效率的子特性和度量指标。基于提出的APP软件性能效率模型，通过实验对APP软件的性能效率进行了度量及相关分析。     

超级电容器的电性能及其在智能仪表上的应用

超级电容器作为一种新型储能元件,目前应用越来越广泛,但在很多细分市场还处于培育阶段,相关行业标准也不尽完善。文中以超级电容器的等效电路模型引出了电性能的特征参数,对比分析了主要标准中电性能特征参数测试方法的差异,提出了在智能仪表中应用超级电容器的要点,对全面认识超级电容器的电性能,在实际工作中正确的应用超级电容器,有一定的参考价值。     

pH-independent dissolution enhancement for multiple poorly water-soluble drugs by nano-sized solid dispersions based on hydrophobic–hydrophilic conjugates

The objective of this study was to achieve an optimal formulation of hydrophilic–hydrophobic conjugates for nano-sized solid dispersions (SDs) with enhanced dissolution of multiple drugs in different gastrointestinal (GI) tract environments. A new conjugate powder with an optimized process was used to fabricate SDs that contained three poorly water-soluble drugs that were also poorly soluble in different dissolution media. The self-assembled nanoparticle formation, drug crystallinity and SD molecular interactions were investigated by measuring the particle size during dissolution testing and physicochemical property analysis (powder X-ray diffraction and Fourier transform infrared spectroscopy). Drug release studies indicated that SD containing conjugated powder significantly improved the dissolution rates of these poorly water-soluble drugs in the GI tract. In addition, particle size analysis showed nano-sized particles in the dissolution media in the early stage with a tendency to reduce smaller particles over time. Physicochemical characterizations demonstrated almost amorphous drug states and hydrogen bonding interactions between the drugs and conjugates in the SD. This study optimized a promising material for SD, and the material was shown to have a promising performance under various pH medium conditions with poorly water-soluble drugs.     

Impact of oxygenated cottonseed biodiesel on combustion,performance and emission parameters in a direct injection CI engine

In the present study, biodiesel production from the crude cotton-seed oil (CSO) and its feasibility to be used as fuel in compression ignition engine was analysed. Single-stage transesterification at molar ratio of 8:1 on crude CSO yielded 94% of cottonseed biodiesel (CBD). Gas chromatogram/mass spectrometry analysis revealed the presence of 19.5% unsaturated and 80.5% saturated esters in cotton seed biodiesel. Taguchi approach identified the stable fuel blend with oxygenate concentration. Increased oxygen concentration up to 20% were also analysed to understand the variation. Higher peak in-cylinder pressure was observed in D80CBD20 fuel blend. Diesel–biodiesel blend with oxygenate significantly affected the ignition delay and also resulted in varied exhaust gas temperature. D80CBD20nB10 showed an increase in brake thermal efficiency, whereas D80CBD20 exhibited higher brake specific energy consumption at full load. Carbon monoxide, hydrocarbon and smoke emission was found to be high in diesel with higher oxides of nitrogen in D80CBD20nB10. This experimental investigation finally revealed that, D80CBD20nB10 improved the combustion and performance characteristics with minimal emissions.

Abbreviations ASTM: American Society for Testing and Materials; BP: brake power; BSEC: brake specific energy consumption; BTE: brake thermal efficiency; CBD: cottonseed biodiesel; CI: compression ignition; CO: carbon monoxide; CO₂: carbon dioxide; CSO: cottonseed oil; DEE: diethyl ether; DOE: design of experiments; EGT: exhaust gas temperature; FTIR: Fourier transform infrared spectrometry; GC/MS: gas chromatogram/mass spectrometry; HC: hydrocarbon; HRR: heat release rate; HSDI: high speed direct injection; IDI: indirect injection; KOH: potassium hydroxide; MFB: mass fraction burned; NaOH: sodium hydroxide; NMR: nuclear magnetic resonance; N₂O: nitrous oxide; NO: nitric oxide; NO₂: nitrogen dioxide; NO _x : oxides of nitrogen; ROHR: rate of heat release; ROPR: rate of pressure rise; SOC: start of combustion; aTDC: after top dead centre; bTDC: before top dead centre     

A large group linguistic Z-DEMATEL approach for identifying key performance indicators in hospital performance management

In hospital management, performance measurement is of vital importance for improving healthcare service quality. The performance of a healthcare organization is often influenced by numerous indicators, and it is unrealistic to manage them all due to the restriction of resources. In addition, the performance measurement for improvement relates to the benefits of many departments, and it is necessary for large number of experts with different backgrounds to participate in the evaluation process of healthcare indicators. In response, this study develops a large group evaluation approach using linguistic Z-numbers and decision-making trial and evaluation laboratory (DEMATEL) to determine key performance indicators (KPIs) for hospital management. For this approach, the complex and uncertain interrelation evaluations among indicators are given by experts using linguistic Z-numbers. An extended DEMATEL method is proposed to determine KPIs based on the cause and effect relationships of performance indicators. Finally, a case study in a rehabilitation hospital is presented to illustrate the effectiveness and usefulness of the proposed large group linguistic Z-DEMATEL approach. The results indicate that incidents/errors, accidents/adverse events, nosocomial infection, nursing technology pass rate, and length of stay are KPIs for the given application.     

不同掺杂设计对类金刚石涂层海水环境摩擦学性能的影响

采用UDP650型闭合场非平衡磁控溅射系统在硅片及316不锈钢基底表面制备了不同掺杂设计的类金刚石涂层(DLC、Cr/DLC和WC/DLC),通过SEM、Raman、硬度仪和划痕仪研究了涂层的结构及力学性能,利用多功能摩擦试验机考察了涂层在大气及海水环境下的摩擦学性能。结果表明,Cr或WC掺杂能显著促进DLC涂层的石墨化,同时提高涂层的结合力及韧性。在摩擦磨损试验中,由于海水的润滑作用,3种涂层在海水环境下的摩擦因数及磨损率均低于大气环境。同时,WC/DLC在3种涂层中表现出最佳的摩擦学性能,这取决于其高的石墨化程度,良好的结合力及优异的韧性。     

数字化核电厂班组SSA测度方法与实验研究

情景意识(SA)问题在数字化核电厂中更为突出。为识别班组共享情景意识（SSA）水平及行为形成因子（PSF）对班组SSA的影响，基于情景意识全面评估技术（SAGAT）建立一种班组SSA测量和计算方法并进行模拟机实验。结果表明，个体SA（ISA）水平与SSA水平有关，ISA级别越高，SSA级别越高；ISA和班组SSA都受到PSF的影响，PSF的状态水平越高，ISA和SSA的水平越高；对于不同的实验场景，操纵员的ISA水平和班组SSA水平不同，这表明风险场景的症状越明显及知识经验水平越好，ISA和SSA水平就越高。最后，通过被试的自评价识别当前PSF的状态水平，主要不良的PSF是班组沟通和合作水平、压力水平、人-机界面等。这些评估结果为提高数字化核电厂人因可靠性和安全水平提供了理论支持。     

Nonlinear performance evaluation model for throughput of AQM scheme using full factorial design approach

The performance of active queue management (AQM) is measured in terms of throughput, delay, queue size, and loss rate. We have carried out the optimized performance measure of throughput for AQM scheme random early detection (RED) using full factorial design (FDD) technique that is a new approach of performance analysis particularly for congestion control algorithms. We have considered the input factors, viz, buffer size, maximum threshold, and the number of file transfer protocol (FTP) sources for the evaluation of RED that can be used for other AQM schemes, viz, adaptive RED, three‐section RED (TRED), and adaptive queue management with random dropping (AQMRD). The effect of each input factor as well as their interactions are evaluated using factorial design technique that results to obtain the nonlinear equation for performance measure in terms of input factors buffer size, maximum threshold, and the number of FTP sources. Finally, we show the contour plots for variation of performance measure throughput (steady state) from minimum to maximum values with respect to the different setting of input parameters.     

无扩口导管拧紧力矩对其密封性能的影响

以某型飞机中无扩口液压导管为研究对象,结合飞机液压导管实际安装以及保压工况,利用有限元软件ANSYS中多线性随动强化来模拟导管弹塑性本构模型;对处于不同安装力矩以及恒定压力下的导管连接件进行仿真分析,研究安装力矩对导管管接头处的应力应变以及密封性能的影响,并给出参考安装力矩。构建液压导管安装试验台,利用力矩扳手采集拧紧力矩值并使用液压油车对导管进行加压试验,验证不同安装力矩对导管管接头密封性能的影响。结果表明:导管与卡套之间的胀形区域产生的大变形以及应力集中是引起导管管接头渗漏的主要原因之一;所提出的密封性能仿真方法可以较为准确地模拟拧紧力矩与密封性能的关系,为实际工程中导管安装提供依据。     

企业社会责任对跨国并购绩效的影响——基于沪深A股上市企业的实证研究

为了帮助我国企业在跨国并购交易中更好地应对因企业社会责任表现所引起的跨国并购风险，平衡好经济利益诉求与社会责任的履行，论文以2009—2017年沪深A股上市公司109起成功的跨国并购事件为研究对象，基于利益相关者理论、社会契约理论与委托代理理论，研究了企业社会责任对于跨国并购绩效的影响，同时考虑了企业所有制、行业一致性和跨国并购经验的调节作用。采用多元回归模型的实证结果表明：1）企业社会责任对跨国并购绩效存在显著的正向影响；2）企业社会责任与跨国并购之间的正向关系受到国有属性与跨国并购经验的负向调节；3）当并购双方属于同一行业时，行业一致性会显著促进企业社会责任对跨国并购绩效的正向影响。建议企业主动披露企业社会责任履行状况并引入国际通行标准，也可借助国际公关公司制定企业社会责任战略。以上研究结论对中国企业履行社会责任方面具有一定的指导意义，同时也为跨国并购绩效的影响因素研究提供了新的理论视角。