外延铁电薄膜相变温度的尺寸效应

考虑外延钙钛矿型铁电薄膜内的等效应力、表面晶格变化和表面电荷引起的退极化效应等机电耦合边界条件,利用铁电薄膜系统的动态金茨堡-朗道方程(DGL),系统分析和讨论了外延铁电薄膜相变温度与临界相变厚度的尺寸效应.结果表明,铁电薄膜相变温度与临界相变厚度完全依赖于各种与薄膜厚度相关的力电耦合边界条件.也给出了BaTiO3外延铁电薄膜相变温度在各种边界条件下随厚度的变化,从结果看出,本文的分析与结论更符合实验数据

单畴外延铁电薄膜的相结构与稳定性

论文采用动态金茨堡-朗道(DGL)方程研究了薄膜厚度与错配应变对(0 0 1)取向单畴外延PbTiO3(PTO)铁电薄膜相结构与稳定性的影响.结合平面内松弛应变(等效应变)、表面效应与退极化场等机电耦合边界条件,通过数值求解DGL方程获得外延单畴铁电薄膜错配应变-厚度相图和错配应变-温度相图.数值分析结果显示,由于生成的界面位错松弛了薄膜内错配应变,在理论高应变区相图与传统分析结果有较大差别,文中发现在更广的理论错配拉应变区出现稳定的四方相(c相)结构和单斜相(r相)结构.结果也显示,随着薄膜厚度的减小,表面效应与退极化效应会把顺电相扩展到更低温度区域,从而压缩稳定的铁电相存在的温度区域

CFE: A Continued Fraction Based on Encoding for Dynamic XML Data

论述了一种基于连分数的动态XMl编码,首先介绍了CfE编码的概念,在此基础上把CfE应用到区间编码和前缀编码,接着对CfE编码的更新算法进行了阐述,最后进行实验对比,说明CfE编码是可行的。This paper introduces a continued fraction based encoding for dynamic XML data.Firstly presents what is CFE encoding.Then applies it to region encoding and prefix encoding.And proposes an algorithm for dynamic update XML data for CFE encoding.Finally,the result shows that CFE encoding is effective.国家自然科学基金资助项目(50604012

Detection of incoherent broadband terahertz light using antenna-coupled high-electron-mobility field-effect transistors

The sensitivity of direct terahertz detectors based on self-mixing of terahertz electromagnetic wave in field-effect transistors is being improved with noise-equivalent power close to that of Schottky-barrier-diode detectors. Here we report such detectors based on AlGaN/GaN two-dimensional electron gas at 77~K are able to sense broadband and incoherent terahertz radiation. The measured photocurrent as a function of the gate voltage agrees well with the self-mixing model and the spectral response is mainly determined by the antenna. A Fourier-transform spectrometer equipped with detectors designed for 340, 650 and 900~GHz bands allows for terahertz spectroscopy in a frequency range from 0.1 to 2.0~THz. The 900~GHz detector at 77~K offers an optical sensitivity about $1~\mathrm{pW/\sqrt{Hz}}$ being comparable to a commercial silicon bolometer at 4.2~K. By further improving the sensitivity, room-temperature detectors would find applications in active/passive terahertz imaging and terahertz spectroscopy.Comment: 4.5 pages, 5 figure

辨别变电站注油设备渗油装置的应用分析

变电站注油设备中油成分起着重要作用,若设备发生渗油可能危害设备绝缘性能而影响电网的安全可靠运行。针对日常运维人员巡视较难发现设备渗漏油情况,设计了一种快速发现变电站内注油设备渗油装置,首先从检测的原理出发,明确装置的结构组成及相关参数,最后进一步通过现场实际检测相关注油设备进行效果分析,研究结果表明此装置能有效地发现变电站中注油设备的微小渗油情况,提高运维人员对设备的日常巡视效率,确保站内渗漏隐患发现的及时性,保证电网设备的安全可靠运行

一种增益自举运算放大器的分析与优化设计

基于开关电容的流水线ADC设计中,运算放大器的建立时间和精度是关键指标。而增益自举运算放大器的建立时间分析比较复杂。本文通过理论推导和模型简化的方法分析其主运放和辅助运放的单位增益带宽及相位裕度对建立时间的影响。提出了一种P型与N型传输函数相同的辅助运放电路,并以此设计了一个高速、低功耗的自举运算放大器

中国海及邻近区域碳库与通量综合分析

中国海总面积约470万平方公里,纵跨热带、亚热带、温带、北温带等多个气候带.其中,南海北依\"世界第三极\"青藏高原、南邻\"全球气候引擎\"西太平洋暖池,东海拥有全球最宽的陆架之一,跨陆架物质运输显著,黄海是冷暖流交汇区域,渤海则是受人类活动高度影响的内湾浅海.中国海内有长江、黄河、珠江等大河输入,外邻全球两大西边界流之一的黑潮.这些鲜明的特色赋予了中国海碳储库和通量研究的典型代表意义.文章从不同海区（渤海、黄海、东海、南海）、不同界面（陆-海、海-气、水柱-沉积物、边缘海-大洋等）,以及不同生态系统（红树林、盐沼湿地、海草床、海藻养殖、珊瑚礁、水柱生态系统等）多层面对海洋碳库与通量进行了较系统地综合分析,初步估算了各个碳库的储量与不同碳库间的通量.就海气通量而言,渤海向大气中释放CO2约0.22Tg Ca-1,黄海吸收CO2约1.15Tg Ca-1,东海吸收CO2约6.92～23.30Tg Ca-1,南海释放CO2约13.86～33.60Tg Ca-1.如果仅考虑海-气界面的CO2交换,中国海总体上是大气CO2的\"源\",净释放量约6.01～9.33Tg Ca-1.这主要是由于河流输入以及邻近大洋输入所致.河流输入渤黄海、东海、南海的溶解无机碳（DIC）分别为5.04、14.60和40.14Tg Ca-1,而邻近大洋输入DIC更是高达144.81Tg Ca-1,远超中国海向大气释放的碳量.渤海、黄海、东海、南海的沉积有机碳通量分别为2.00、3.60、7.40、7.49Tg Ca-1.东海和南海向邻近大洋输送有机碳通量分别为15.25～36.70和43.39Tg Ca-1.就生态系统而言,中国沿海红树林、盐沼湿地、海草床有机碳埋藏通量为0.36Tg Ca-1,海草床溶解有机碳（DOC）输出通量为0.59Tg Ca-1;中国近海海藻养殖移出碳通量0.68Tg Ca-1,沉积和DOC释放通量分别为0.14和0.82Tg Ca-1.总计,中国海有机碳年输出通量为81.72～103.17Tg Ca-1.中国海的有机碳输出以DOC形式为主,东海向邻近大洋输出的DOC通量约15.00～35.00Tg Ca-1,南海输出约31.39Tg Ca-1.综上,尽管从海-气通量看中国海是大气CO2的\"源\",但考虑了河流、大洋输入、沉积输出以及微型生物碳泵（DOC转化输出）作用后,中国海是重要的储碳区.需要指出的是,文章数据是基于中国海各海区碳循环研究报道,鉴于不同研究方法上的差异,所得数据难免有一定的误差范围,亟待将来统一方法标准下的更多深入研究和分析.国家重点研发计划项目(编号:2016YFA0601400);;国家自然科学基金项目(批准号:91751207、91428308、41722603、41606153、41422603);;中央高校基础研究项目(编号:20720170107);;中海油项目(编号:CNOOC-KJ125FZDXM00TJ001-2014、CNOOCKJ125FZDXM00ZJ001-2014)资

Design and implementation of the energy management and intelligent monitoring system of a zero energy consumption house

针对2013中国国际太阳能十项全能竞赛比赛规则及零能耗建筑的特点,结合比赛地点山西大同的气候数据,给出了厦门大学参赛作品,零能耗小屋Sunny InSIdE的能源管理与智能监控系统设计方案。以光伏建筑一体化理论为基础,设计15.25kW光伏并网发电系统,并用相关软件对能耗平衡进行了模拟验证。以三菱PlC为核心,构建了能源管理与智能监控系统,分析了不同条件下空调、相变及遮阳系统的控制策略,并给出具体实现方法。According to the rules of the Solar Decathlon China 2013 and the characteristics of zero energy consumption house, combining with the climate data in competition city—Datong Shanxi, an energy management and intelligent monitoring system for the zero energy consumption house called Sunny Inside from Xiamen University was born.A 15.25kW photovoltaic grid connected power system was designed based on building integrated photovoltaic theory, and used relevant simulation software to test energy balance property.An energy management and intelligent monitoring system was constructed based on Mitsubishi PLC, analyzed the control strategy of heating ventilation and air conditioning, phase-change material and shading system under different conditions, and gave a concrete realization method

Analysis and compensation of the springback of metal wire bending

回弹对于线材折弯加工的精度影响非常明显,为探索线材回弹规律,建立了线材折弯过程的数学模型,以材质45钢的线材为研究对象,进行有限元分析与试验研究。验证了有限元分析与试验方法获得回弹角度数据的一致性,考虑折弯角度和线材直径两个主要参数对回弹的影响,建立了线材折弯回弹角度的双参数数学模型。将回弹角度双参数数学模型应用于弯丝机的补偿模块,进行线材折弯试验,取得明显的折弯补偿效果,使线材折弯加工精度达到了1°,实现了对任意折弯角度和线材直径的线材折弯回弹补偿。It is evidently shown that the springback has an influence on the accuracy of wire bending process.In order to explain the law of springback,a mathematical model of wire bending process was built for 45 steel wire,and finite element analysis and experimental research were carried out.The consistence of springback angle was attained through the finite element simulation and experiments.Considering the influence of the two main parameters of bending angle and wire diameter,a double-parameter mathematical model of springback angle was established.When the double-parameter mathematical model was applied to the compensation module of wire-bending machine for the test of wire bending,a prominent compensation effect was achieved,the processing precision was up to 1° with the springback compensation of arbitrary bending angle and wire diameter realized.厦门市产业技术攻关资助项目(3502Z20131007

Cloning and Expression of the Leukotoxin Gene SH from Fusobacterium necrophorum

坏死梭杆菌白细胞毒素是坏死杆菌病的主要致病因子,白细胞毒素基因(lkT)是其编码基因。以分离到的国内牛源坏死梭杆菌fn(A)菌株f4基因组dnA为模板,应用PCr方法扩增白细胞毒素基因SH片段,克隆至PMd18-T载体上,以bAMHⅠ和HIndⅢ酶切的目的片段SH与相应酶切的PET32A载体连接构建PET32A-SH重组表达质粒,经转化E COlI bl21(dE3)后用IPTg进行蛋白诱导,SdS-PAgE检测重组蛋白表达情况。结果表明:扩增基因序列大小为1800bP,SdS-PAgE检测重组蛋白有效表达,表达得到大小为80.2kdA的目的蛋白,采用镍柱亲和层析方法纯化SH重组蛋白,获得了纯度达95%的重组蛋白;经WEST-Ern-blOT证实,该蛋白对抗坏死杆菌阳性血清具有反应活性。The leukotoxin of Fusobacterium necrophorum(FN) is considered to be one of the main virulence factors.The lkt gene encodes for FN.In this study,the SH fragment of lkt gene was amplified by PCR using the F4 genome as the template,which was isolated from the Chinese Fusobacterium necrophorum strain.The fragment was then cloned to the pMD18-T vector for sequencing.Thereafter,the SH fragment was subcloned into the multiple cloning sites of the pET32 to construct pET32a-SH recombinant plasmid,which was then trans-formed into E.coli BL21(DE3) with IPTG induction for expression.SDS-PAGE was used to analyze the recombinant protein.The results showed that the SH fragment of about 1800 bp was amplified and was about 80.2 kDa.The fusion protein was purified by Ni-NTA affinity chromatography under denature conditions,and their purity was above 95%.Western-blot analysis indicated the SH fragment had anti-genicity against Fusobacterium necrophorum.“十五”国家科技攻关子课题(2002BA518A04);吉林省科技发展计划项目(20070570);吉林市科技发展计划项目(200805