The Experimental Study on Flow Boiling Heat Transfer of Working Fluid R245fa in Horizontal Tube

设计了管内沸腾换热系数及总传热系数测定试验台架,对R245fa工质在内径6 mm水平光管内的流动沸腾换热特性进行试验研究。测试质流密度为50 ~; 150 kg /(m~2·s),工质蒸发温度为50, 60和70℃。结果表明:; 随着工质含汽率的增加,R245fa的流动沸腾换热系数呈先增大后降低趋势。对于304不锈钢套管式换热器,烟气与R245fa工质进行换热的总传热系数; 约在40 ~ 65 W/(m~2·K) 。A bench - scale facility was designed for testing the flow boiling heat; transfer coefficient and the total heat transfer coefficient. The; boiling heat transfer characteristics of the R245fa refrigerant were; studied in a horizontal smooth tube with 6 mm inner diameter. The; parameters investigated were mass flow rate (50 ~ 150 kg /(m~2·s)),; evaporation temperature (50, 60 and 70 ℃). The results showed that the; flow boiling heat transfer coefficient of R245fa increased with the; increase of rate of vapor content, and decreased slightly with the; further increase of rate of vapor content. The total heat transfer; coefficient of the flue gas and the R245fa is about 40 ~ 65 for the 304; stainless steel heat exchanger.国家国际科技合作专项资助项

Studies of Microstructure and ACEL Characteristicsin Zinc Sulfide Thin Films

用电子束研制不同介质膜作绝缘层的掺铒硫化锌交流电致发光薄膜器件，用X射线衍射技术测量薄膜表面结构，发现薄膜多晶的沉积有择优取向的趋势。观察不同绝缘层交流电致发光器件的初始稳定过程，讨论绝缘层质量对交流电致发光器件的影响。The devices of ZnS:Er 3+ thin film of alternating current electroluminescence (ACEL) are prepared with different insulation dielectric film respectivily. Their insulation layers are prepared by electron beam evaporation. The crystallite structure of the ZnS:Er 3+ films are measured by using X ray diffraction (XRD) technology. The results show that the deposited polycrystalline films have a trend of preferred orientation. The originally electroluminescence steady process of the thin film devices with different insulation layers are observed, and the effects of prepared insulation dielectric layer quality on alternating current electroluminescence are discussed as well.福建省自然科学基

试论上市公司高管薪酬的粘性——基于我国金融业上市公司的研究视角

本文以中国股票市场中金融业上市公司为样本,对高层管理人员薪酬粘性问题展开研究。研究发现,高管薪酬存在粘性,即在公司绩效上升时高管薪酬增加幅度显著高于公司绩效下降时的减少幅度。进一步研究还发现,公司规模、股权安排、负债比例等一系列特征对高管薪酬粘性具有显著的影响关系。本文研究不仅揭示我国上市公司高管薪酬变动特征,同时也为学术界进一步研究高管薪酬粘性问题提供理论基础与数据支持

The Characterization of InGaN and InGaN/GaN Quantum Wells Grown by LP-MOCVD

【中文摘要】 利用 MOCVD系统在 Al2 O3衬底上生长 In Ga N材料和 In Ga N/ Ga N量子阱结构材料。研究发现 ,In Ga N材料中 In组份几乎不受 TMG与 TMI的流量比的影响 ,而只与生长温度有关 ,生长温度由 80 0℃降低到 74 0℃ ,In组份的从 0 .2 2增加到 0 .4 5 ;室温 In Ga N光致发光光谱 (PL)峰全半高宽 (FWH M)为 15 .5 nm;In Ga N/ Ga N量子阱区 In Ga N的厚度 2 nm,但光荧光的强度与 10 0 nm厚 In Ga N的体材料相当。 【英文摘要】 InGaN bulk material and InGaN/GaN quantum well were grown by low pressure metal organic chemical vapor deposition(LP MOCVD),and they were characterized by X ray and photo luminescence(PL) maximum at room temperature.The PL full width of half of InGaN grown at 800 ℃ is 15.5 nm at room temperature and the peak wavelength is 437 nm.The In composition in InGaN did not dependent on the ratio of TMG and TMI but on the growth temperature and the In content increases from 0.22 at 800 ℃ to 0.45 at 740 ℃.The In com...福建省自然科学基金资助项目 (E9820001) ; 国家教育部高等学校骨干教师资助计划项目资

Innovation and Practice on the Construction of Marine Biological and Ecological Field Practice Base in the Yangtze Estuary and Adjacent Sea

文章以国家自然科学基金委首个海洋科学类野外实践基地——长江口及邻近海域海洋生物与生态野外实践基地的建设为背景,从充分利用区位优势、突出综合实践功能、有效整合校际资源、积极筹措建设经费、创新基地管理体制、加强基地开放共享、促进科教有效融合、提升平台建设水平等八个方面进行了创新与实践,并对建设过程中的体会与问题进行了探讨。Based on the background of the construction of marine biological and ecological field practice base in the Yangtze estuary and adjacent sea which is the first field practice base of marine science supported by the National Natural Science Foundation of China,we try to make some innovation and practice from the following eight aspects： taking full advantage of location,highlighting the comprehensive practical function,integrating universities＇ resources effectively,raising funds for construction actively,innovating management system of field,strengthening open sharing of bases,promoting effective integration of science and education,and improving the level of platform construction. At last,this paper discusses the experience and problems in the construction process.国家自然科学基金野外实践能力提高项目（项目编号：J1310037）; 浙江省高等教育教学改革项目（项目编号：jg2015090

研究生对生成性课堂的参与(笔谈)——厦门大学教育研究院“高等教育研究方法”第十三次课反思

\"高等教育研究方法\"这门课具有研究型课堂的特征。其第十三次课的主题是对反思日志做一次元研究。反思日志是学习\"高等教育研究方法\"课的重要工具,它不仅是课堂教学的缩影,而且是课堂时效的呈现,更是学生自我成长的印证。反思日志勾勒着整个课堂进程的图景,反映着学生的收获、困惑、不足以及对自己未来改进方向的认识等。第十三次课以生成式教学引导学生主动参与课堂,通过对反思日志重新审视,让学生成为思考的主体、学习的主体、研究的主体,实现自我成长、自我发现、自我唤醒的课堂教学改革目标

The Bee Colony Algorithm Calculation method of the Convective Heat Transfer Coefficient in the Spindle

随着对零件加工精度的要求不断提高,确定机械主轴准确的瞬态温度场显得尤为重要。对流换热系数作为温度模型的重要参数,对机械主轴温度场的准确性有着至关重要的影响。传统的确定对流换热系数的方法具有计算精度差,不能适应变化的工况等问题。因此,针对上述问题以170CP06-DM机械主轴性能测试系统为例,首先采用有限元法建立机械主轴的瞬态温度场数学模型,其次提出了一种基于蜂群算法确定对流换热系数的方法。实验结果表明,采用所提建模方法与传统的建模方法相比计算精度有所提高,其中,最大误差、平均误差、均方差的计算精度分别提高了84.13%,83.70%,85.23%。</p

Selection of working fluid for ORC system to recover low-temperature waste heat

利用有机朗肯循环（ORC）技术高效回收低温余热的关键之一是选用合适的工质。本文针对热源温度介于120~220℃区间内的ORC系统,选用R123,R245fa,R600和R1233zd（E）四种工质为研究对象,通过对50 kW的ORC系统的运行分析并结合模拟计算,详细讨论不同工质的热力特性以及蒸发温度、蒸发压力、蒸发器出口过热度对ORC系统热效率的影响。结果表明,对于透平膨胀机入口工质温度在100~150℃区间、热源温度在120~220℃区间的低温余热回收ORC系统,工质R600性能表现最佳,但易燃;从不可燃性、热力特性、环境友好性及设备成本方面考虑,R1233zd（E）具有优势,但工质价格较高。One of the key point of using the high-efficiency recovery technology of Organic Rankine Cycle（ORC）to recover low-temperature waste heat is to choose suitable working fluid.For the ORC system to recover low-temperature heat source between 120℃ and 220 ℃,four kind of working fluids are studied,which are R123,R245 fa,R600and R1233zd（E）.The effect of the thermodynamic properties,evaporating temperature,evaporating pressure,superheat degree of the outlet of the evaporator of different working fluids on the thermal efficiency of the ORC system is analyzed.The results show that for the ORC system to recover low-temperature waste heat with the inlet temperature of the expander between 100 ℃ and 150 ℃,and the heat source temperature between 120 ℃ and220 ℃,R600 is the most suitable working fluid,but inflammable.Considering from the nonflammablity,thermal property,environmental friendliness and equipment cost,R1233zd（E）has advantages,but the price of working fluid is higher.国家国际科技合作专项（2013DFG60120