High air stability of threshold voltage on gate bias stress in pentacene TFTs with a hydroxyl-free and amorphous fluoropolymer as gate insulators

We investigated the air stabilities of threshold voltages (V_th) on gate bias stress in pentacene thin-film transistors (TFTs) with a hydroxyl-free and amorphous fluoropolymer as gate insulators. The 40-nm-thick thin films of spin-coated fluoropolymer had excellent electrical insulating properties, and the pentacene TFTs exhibited negligible current hysteresis, low leakage current, a field-effect mobility of 0.45 cm²/Vs and an on/off current ratio of 3 × 10⁷ when it was operated at −20 V in ambient air. After a gate bias stress of 10⁴ s, a small V_th shift below 1.1 V was obtained despite non-passivation of the pentacene layer. We have discussed that the excellent air stability of V_th was attributed to the insulator surface without hydroxyl groups.     

白光光源驱动与控制系统的设计与实现

现代光电检测技术中,光源光谱的稳定性对实验结果的影响很大.研究设计了一种白光光源的驱动与控制系统,该系统包括可控恒流源、保护电路、光功率自动控制和温度监控等部分.整个系统以单片机AT89C52为核心,结合外围电路,用数字控制技术代替模拟电路控制.软件设计中采用了PID控制算法,有效地抑制了输出光功率的漂移,改善了输出光功率的稳定性.     

一种新的最优小波基选择准则及其应用

针对分数低阶口稳定分布信号具有显著脉冲这一特性,参照最优小波包基选择的熵准则,提出了一种针对该类噪声的最优小波基选择新准则,解决了以往最优小波基选择的熵准则中,由于需计算二阶统计量而不适合分析分数低阶口稳定分布信号的问题.还得出了针对该类信号,在运用该新准则进行判别最优小波基时,只需对各个小波基函数在第1层尺度下的变换系数进行对比判别的结论,极大地减化了以往多尺度的判别过程.将新准则应用于医学超声图像消噪时,获得了较好的效果.     

Ising模型在经济物理学中的应用

利用Ising模型模拟了金融市场价格的变化,对相应的收益率序列分析发现,概率密度函数具有标度关系、定性符合L6vy稳定分布;序列又具有多重分形的特征。模拟结果与实证研究相一致,表明Ising模型能够有效地描述金融市场价格的形成机制。     

PALAEO‐EXPOSURE SURFACES IN THE APTIAN DARIYAN FORMATION,OFFSHORE SW IRAN: GEOCHEMISTRY AND RESERVOIR IMPLICATIONS

Palaeo‐exposure surfaces within and at the top of the carbonate‐dominated Aptian Dariyan Formation have been poorly studied in the Iranian sector of the Persian Gulf. This paper presents an integrated sedimentological and geochemical study of the Dariyan Formation at four oil and gas fields located in the western, central and eastern parts of the Gulf. Facies stacking patterns in general indicate shallowing‐upwards trends toward the exposure surfaces, which are interpreted to correspond to unconformities. The Dariyan Formation in the study area is divided into upper and lower carbonate units by a deep‐water, high‐gamma shale‐marl interval. At fields in the western and central Gulf, significant diagenetic changes were recorded in the top of the upper carbonate unit, including meteoric dissolution and cementation, brecciation and paleosol formation. An exposure surface is also present at the top of the lower carbonate unit in all the fields in the study area, and is associated with meteoric dissolution and cementation of grain‐dominated facies. Age calibration of studied intervals was carried out using microfossil assemblages including benthic and planktonic foraminifera. Negative excursions of both δ¹⁸O (?10‰ VPDB) and δ¹³C (?0.66‰ VPDB) were recorded in weathered intervals located below the unconformity surfaces. A sequence stratigraphic framework for the Dariyan Formation was established by integrating sedimentological, palaeontological and geochemical data. The δ¹³C curve for the formation in the Iranian sector of the Persian Gulf can be correlated with the reference curve for the northern Neotethys and used as a basis for regional stratigraphic correlation. Where the top‐Aptian unconformity is present, it has resulted in an enhancement of the reservoir characteristics of the underlying carbonate succession. Accordingly, the best reservoir zones in the Dariyan Formation occur in the upper parts of the lower and upper carbonate units which are bounded above by significant palaeo‐exposure surfaces.     

稳定同位素及矿物元素分析在谷物产地溯源中应用的研究进展

产地溯源是谷物真伪鉴别的重要研究内容之一。稳定同位素及矿物元素分析技术具有灵敏度高、可靠性强等优点,通过关联分析谷物中的稳定同位素、矿物元素信息与谷物的产地环境、种植方式等,并借助化学计量学手段进行分类、判别、建模等,可达到产地溯源的目的。本文系统分析了近10余年国内外有关稳定同位素及矿物元素分析技术在谷物产地溯源中的研究进展,在此基础上提出当前谷物产地溯源存在的问题,及今后稳定同位素和矿物元素分析技术在谷物产地溯源中的发展方向和研究重点。     

西藏青稞碳、氢、氧、氮同位素在不同生态域中差异性研究

目的研究青稞中稳定同位素在不同生态域的差异性。方法 2016年在西藏不同生态域种植不同基因型的青稞品种,利用同位素质谱仪测定不同生态域的青稞样品的稳定碳、氢、氧、氮同位素,结合Kolmogorov-Smirnov和Levene统计量分别检验所有数据的正态性和方差同质性,满足方差齐性时采用LSD多重比较,不满足方差齐性时采用Games-Howell多重比较法进行分析,解析不同生态域青稞样品中稳定碳、氢、氧、氮同位素。结果不同区域种植的青稞δ~(13)C值、δ~(15)N值、δ~(18)O值和δD值差异均极其显著(P0.01)。结论稳定碳、氢、氧、氮同位素指纹可用于青稞的产地溯源,可以进一步研究青稞中多元素组成特征及其用于青稞产地溯源的可行性。     

孢粉稳定同位素研究进展初探

孢粉作为环境演变的指示剂,在开展古气候、古环境变化研究方面具有重要的研究意义和研究价值,但在孢粉研究过程中受到孢粉鉴定分类水平及鉴定者的鉴定水平等方面的影响,对古环境、古气候的研究就很难达到准确的定量研究的标准,对孢粉稳定同位素进行研究反而很好的解决孢粉研究过程中出现的不足。概括了目前国内外对孢粉稳定同位素的研究现状,对现在应用于孢粉同位素中的方法进行分析归纳,结合其它应用同位素的所获得的最新成果进行对比,从而指出现在孢粉稳定同位素研究过程中存在的问题和不足,提出未来孢粉稳定同位素发展的新趋势。     

1.5 MPa多喷嘴对置式水焦浆气化炉的模拟与优化

针对w（水焦浆）和氧焦比预测优化过程未采用严格反应机理模型,工艺参数的预测优化与实际生产存在较大偏差的情况,以UniSim Design流程模拟软件为工具,采用Gasifier反应器严格机理模型建立了1.5 MPa多喷嘴对置式水焦浆气化炉模型,并根据工业数据对水焦浆气化炉进行标定,标定结果相对误差小于2%,同时研究了氧焦比和w（水焦浆）对焦煤气化工艺参数的影响。结果表明：w（水焦浆）和氧焦比是影响水焦浆气化过程和粗煤气组成的关键因素,通过气化炉模型标定和优化分析,石油焦的氧焦比控制范围为0.95~1.10,为焦煤浆气化工艺生产实践指导提供了理论依据。