Temperature dependant flash memory erase transient simulation (Part I)

We present a detailed and accurate physics based transient simulation for modeling flash memory erasing at ambient and non-ambient temperatures. Typical cells are erased by moving electrons from the floating gate to the drain, source or substrate. Part I of this paper addresses substrate erase modeling using a simulation based on the solution to Poisson’s equation with temperature as an independent variable. The goal of this paper is to demonstrate the derivation of an accurate erase simulation and show the effects of temperature on the threshold voltage shift during the erase process. Several papers have been published on this topic but fail to present detailed derivations and none using this exact set of equations to model the temperature dependent erasing process.     

利用有限差分法计算空间目标红外特征

空间目标的红外辐射特性是对空间目标进行探测与识别的重要依据.首先分析了空间目标与外界环境的热交换关系,确定了目标表面的边界条件,推导出边界单元的有限差分形式,针对空间目标的遮挡问题.开展了判断方法的讨论,为准确计算目标的表面温度场奠定了基础.其次利用有限差分法求解其导热微分方程,获得了目标表面温度场分布特性;将总红外辐射分解为自发辐射和反射辐射两部分,分别给出了计算自发辐射强度和反射辐射强度的计算式.最后以某空间目标为例,利用数值方法计算表面温度场,并在此基础上计算了红外辐射强度的空间分布,对计算结果进行了分析.     

基于辐射特征的干扰弹检测方法研究

根据干扰弹在起燃时间内辐射能量急剧增加的特点,利用图像序列中图像灰度斜率的突变进行干扰检测是一种比较有效的方法。利用仿真选择有效的数据平滑方法对灰度变化斜率进行估计,以消除焦平面探测器采样特性和噪声的影响,定量分析了影响干扰弹检测概率的各种因素,评价了利用辐射特征检测干扰弹的优点与不足。     

Radiation polymerization of thermo-sensitive poly (N-vinylcaprolactam)

Temperature-sensitive poly (N-vinylcaprolactam) both in water-soluble state and in gel was prepared by γ-radiation polymerization. The effects of radiation dose, radiation dose rate and monomer concentration on polymerization and the low critical solution temperature characteristics of the polymer were studied. The results show that the polymer prepared within certain radiation dose (beyond 2 kGy) and dose rate range (2–14 Gy/min) has good temperature sensitivity and uniformity.     

Temperature Effect on Hydrogen Evolution Reaction at Au Electrode

The temperature dependence of hydrogen evolution reaction (HER) at a quasi-single crys-talline gold electrode in both 0.1 mol/L HClO₄ and 0.1 mol/L KOH solutions was investigated by cyclic voltammetry. HER current displays a clear increase with reaction overpotential (η) and temperature from 278～333 K. In 0.1 mol/L HClO₄ the Tafel slopes are found to increases slightly with temperature from 118 mV/dec to 146 mV/dec, while in 0.1 mol/L KOH it is ca. 153±15 mV/dec without clear temperature-dependent trend. The apparent activation energy (Ea) for HER at equilibrium potential is ca. 48 and 34 kJ/mol in 0.1 mol/L HClO₄ and 0.1 mol/L KOH, respectively. In acid solution, Ea decreases with increase in η, from Ea=37 kJ/mol (η=0.2 V) to 30 kJ/mol (η=0.35 V). In contrast, in 0.1 mol/L KOH, Ea does not show obvious change with η. The pre-exponential factor (A) in 0.1 mol/L HClO₄ is ca. 1 order higher than that in 0.1 mol/L KOH. Toward more negative potential, in 0.1 mol/L HClO₄ A changes little with potential, while in 0.1 mol/L KOH it displays a monotonic increase with η. The change trends of the potential-dependent kinetic parameters for HER at Au electrode in 0.1 mol/L HClO₄ and that in 0.1 mol/L KOH are discussed.     

负载Pd催化剂的表面碱性和NO吸附关系

催化消除汽车尾气中氮氧化物（ＮＯｘ）物种在大气环境保护方面有着重要意义．随着环保法规的越来越严格,研制活性更高,稳定性更好的 ＮＯｘ催化剂势在必行．贵金属 Ｐｔ、Ｐｄ、Ｒｈ三效催化剂（ＴＷＣ）能够同时去除 ＮＯｘｓ、ＣＯ、ＨｘＣｙ三种污染物,生产工艺比较成熟．其中Ｒｈ是公认的促使ＮＯｘ还原为Ｎ２的最有效组分,但Ｒｈ的价格较高且资源贫乏,限制了其实际应用．所以人们一直尝试采用一种廉价的替代品．单Ｐｄ的三效催化剂,由于其相对低廉的价格,较好的耐高温性能,有可能是合适的选择［１－２］．此外,以ＮＨ３为还…     

Development of GC–MS/MS method with programmable temperature vaporization large volume injection for monitoring of 17β-estradiol and 2-methoxyestradiol in plasma

Monitoring of estradiol and its metabolites in biological samples is essential for the accurate diagnosis of a number of endocrine diseases. In this study, a sensitive, precise and specific GC–MS/MS method for the quantification of 17β-estradiol (17-BE) and its main metabolite, 2-methoxyestradiol (2-MEOE), in plasma was developed and validated. Plasma concentrations of these steroids are currently investigated as diagnostic markers for pre-eclampsia, a systematic disorder of pregnancy and a leading cause of maternal and fetal morbidity and mortality worldwide.     

高分子基PTC复合材料的研究及其应用

本文概述了高分子基PTC复合材料最近的研究动态，阐述了其作为热敏材料在自控温加热系统和过流保护元件方面的广泛应用。     

C12-s-C12·2Br与低碳醇混合水溶液胶团化行为的温度效应和焓/熵补偿

季铵盐Gemini表面活性剂C12-s-C12·2Br(s=2,3,4,6)与丙醇、丁醇、戊醇、己醇混合水溶液的In(cmc)随温度升高而逐渐增大.计算所得热力学数据表明,C12-s-C12·2Br与醇混合胶团化过程服从熵驱动机理,也出现了焓/熵补偿现象.随着温度上升,熵驱动力增大,在指定温度时,醇分子烷烃链上碳原子数n增大使△Gm0值减小,胶团结构更加稳定;而增加s使值增大,胶团稳定性下降.     

Characterization of a 4-miktoarm star copolymer of the (PS-b-PI)3 PS type by temperature gradient interaction chromatography

Temperature gradient interaction chromatography (TGIC) was applied for the separation of a complex miktoarm star copolymer which has one polystyrene (PS) arm and three polystyrene-b-polyisoprene (PS-b-PI) diblock copolymer arms. Such miktoarm star polymers are much more difficult to characterize than branched homopolymers since the byproduct, typically polymers with missing arm(s) or coupled products, have not only different molecular weights but also different compositions. TGIC was able to fully separate the byproducts, and the composition of the molecular species corresponding to the different separated elution peaks was determined by two methods, fractionation/NMR and multiple detection (UV and RI). A reasonable agreement between the results of the two methods was obtained. By using the composition found, the corresponding molecular weights were determined by multi-angle light scattering detection. Based on the composition and the molecular weight we were able to identify the structure of the different molecular species.