纳秒强脉冲粒子束与纳米科技

高功率密度（１０＾６－１０＾１０）Ｗ／ｃｍ＾２脉冲电子束、离子束和激光束与靶物质相互作用产生态高温、高压和烧蚀作用，其过程已被用于材料改性、表面涂复及低维材料研究等广泛领域。重点介绍赝火花（Ｐｓｅｕｄｏｓｐａｒｋ）脉冲粒子束在纳米科技中的应用。     

大化水电站二期导流工程导流明渠泥沙冲淤

大化水电站１９８０年１０月下旬二期导流工程截流前，导流明渠淤积泥沙２５２０９０ｍ＾２，将导流明渠基本堵塞，靠人力及机械清淤无法实现按计划截流。经过对泥沙运动的研究，采用主河槽予抛方案提高上游水位，使导流明渠水流流速由１．０ｍ／ｓ遂渐增大到３．２５ｍ／ｓ，在短短的１７天内冲走２５２０９０ｍ＾３淤积泥沙，实现了按计划截流。     

钴取代的BaNi2W六角铁氧体

研究了ＢａＮｉ２－ｘＣｏｘＦｅ１６Ｏ２７（ｘ＝０,０．２,０．２５,０．４,０．４２,０．５,０．８４）六角铁氧体多晶材料的磁特性。结果,取向度大于７５％,介电损耗小于５×１０＾－３,饱和磁化强度为３６６ＫＡ／ｍ几乎不变。磁晶各向异性场为２００ｋＡ／ｍ≤Ｈａ≤１１４０ｋＡ／ｍ,这类材料可应用于Ｘ至Ｋａ波段的微波器件。     

硅整流管表现保护材料负电晕带电特性的研究

研究了负针－板电晕电对台面型高压硅整流管管芯上保护材料的影响，负电晕的注入。使Ｓｉ－ＳｉＯ２－绝缘材料的界面等效电荷为负电荷，它引起管芯表面耗尽区的展宽。数值计算表明，电晕带电使界面等效电荷为－１０＾１１ｃｍ＾－２范围。     

潜水电泵的主要系列简介(一)

１ ＱＹ系列ＱＳ系列和Ｑ系列小型潜 水电泵 （１）型号表示方法 产品型号举例： Ｑ１０－４４／２－３表示三相干式上泵型潜水电泵，流量１０ｍ３／ｈ，扬程４４ｍ，２级泵，额定功率３ｋＷ； ＱＹ２５－１７－２．２表示三相充油式上泵型潜水电泵，流量２５ｍ３／ｈ，扬程１７ｍ，额定功率２．２ｋＷ； ＱＳ６５－１８－５．５表示三相充水式上泵型潜水电泵，流量 ６５ｍ３／ｈ，扬程１８ｍ，额定功率５．５ｋＷ。 （２）使用条件 （ａ）主要使用于一般清水，如河水、湖水和井水等场合； （ｂ）水温不超过４０℃ ； （ｃ）水的ｐＨ值为６…     

异丙醇在 Pt 微盘电极上的电化学氧化

采用微电极伏安技术,研究异丙醇在Ｐｔ微盘电极（ｒｄ＝１０μｍ）上氧化的稳态和暂态的电化学行为,得出一系列重要的动力学参数：异丙醇氧化反应的反应电子数ｎ为１．９５,扩散系数Ｄ为３．２２×１０－５ｃｍ２／ｓ,传递系数β值为０．１２,电极体系的交换电流密度Ｊ０为３．０×１０－４Ａ／ｃｍ２,标准速度常数Ｋｓ为１．６０×１０－４ｃｍ／ｓ。由计算结果我们可以推测,异丙醇在Ｐｔ微盘电极上酸性水溶液体系中的氧化过程由稳态传质扩散及电化学极化联合控制,其中,异丙醇分子到电极表面的扩散吸附为快速步骤,吸附的异丙醇分子在电极表面脱氢为慢步骤;异丙醇在Ｐｔ微盘电极上的电化学氧化为异丙醇脱氢生成丙酮的２电子转移反应,并由此推测其可能的反应途径。     

合金凝固组织对氢扩散和 MH 电极性能的影响

用电位阶跃法和恒流充放电法研究了贮氢合金凝固组织中氢的扩散行为和合金氢化物电极放电的速度特性。研究表明，合金ＭｌＮｉ３．４５（ＣｏＭｎＴｉ）１．５５各凝固组织中氢的扩散系数Ｄｈ和其氢化物的电极性能均明显不同。随合金凝固时冷却速度增大，晶胞体积和氢扩散系数减小。雾化快凝合金粉末随颗粒尺寸由２００目变化至３６０目（冷却速度增大）时，其Ｄｈ由３．０６×１０－７（ｃｍ２·ｓ－１）减小至７．４７×１０－９（ｃｍ２·ｓ－１）；定向凝固组织随凝固速率Ｒ＝４８μｍ／ｓ增大时，Ｒ＝２２０μｍ／ｓ时，其Ｄｈ则由７．０３×１０－９（ｃｍ２·ｓ－１）增大至１．３１×１０－８（ｃｍ２·ｓ－１）。合金电极的高倍率放电效率主要取决于氢在合金中的扩散速度和电极表面的电催化活性。定向凝固组织具有良好的放电速度特性与Ｎｉ元素在其凝固组织中富集和偏析以及晶体沿一定方向结晶生长关系密切     

6H—SiC平面状及圆柱状p^＋n结击穿电压的分析

采用有效电离系数导出了６Ｈ－ＳｉＣ平面状及圆柱状ｐ＾＋ｎ结击穿电压的分析表达式，有效电离系数是由电子和空穴的电离系数获得的。示出在平面状情况下，基区掺杂浓度在１０＾１６￣４×１７＾１７ｃｍ＾－３区间内，所计算的击穿电场和击穿电压与所公布的实验结果完全一致。所得分析结果可用于对６Ｈ－ＳｉＣ器件中击穿电压作出简单的预测。     

锂铝-二硫化铁热电池发展现状

简要论述了天津电源研究所（ＴＩＰＳ）锂铝合金－二硫化铁热电池发展现状。采用新型ＦｅＳ２阴极添加剂及独特的添加工艺,有效消除了放电初期电压峰,显著地提高了电池工作电压精度。介绍了在缩短激活时间、降低内阻、提高电池大电流工作能力和脉冲放电能力等方面取得的进展。在１．５Ａ／ｃｍ２电流密度下,其内阻一般不超过０．３Ω,在４Ａ／ｃｍ２～５Ａ／ｃｍ２电流密度下,其内阻可控制在０．６Ω～０．８Ω范围内。此外,本文还介绍了锂铝合金－二硫化铁热电池的环境适应能力。电池可在－５０℃～＋８５℃温度环境下正常工作,在激活状态下,电池可承受１０７８ｍ／ｓ２的离心作用和３００００ｍ／ｓ２～３５０００ｍ／ｓ２作用时间６ｍｓ～８ｍｓ的瞬时冲击。在非工作态下,可承受１５００００ｍ／ｓ２～１８００００ｍ／ｓ２的冲击。     

焊接技术的新进展

激光的能量密度达１０＾７～１０＾９Ｗ／ｃｍ＾２,汽车制造业中激光焊接生产线广泛应用是２０世纪突出的成就。电子束的能量密度达１０＾８～１０＾９Ｗ／ｃｍ＾２,电子束焊机日趋大型化,电子枪加速电压已高达５００ｋＶ,焊透厚度可达５００ｍｍ,在大厚度构件、高熔点活性材料的焊接中长期应用。近年激光焊和电子束焊在高精度自动化生产中也得到应用。适用中厚板钢结构的ＴＩＭＥ焊接电流密度大、送丝速度快、熔数率可达３０ｋ     

Repetition rate scaling up to 100 kHz of a small-scale (50 W) kinetically enhanced copper vapor laser

We report on the pulse repetition frequency (PRF) scaling of a small-scale (25 mm bore and 0.61 m long) copper vapor laser (CVL). When operated as an elemental CVL, the laser had a stable output power of 15 W at 15 kHz PRF (9.6% efficiency). After the addition of small quantities of hydrogen and hydrogen chloride to the neon buffer gas, the maximum recorded stable output power increased to 41 W at 25 kHz PRF (1.4% efficiency). This represents a record stable specific output power of 0.14 W cm/sup -3/. Pulse repetition frequency scaling of the laser was demonstrated up to 100 kHz where the output power was 9.0 W. By operating the laser at elevated input powers, transient output powers of over 50 W were achieved between PRFs of 25-40 kHz. These results are the highest recorded specific output powers (0.17 W cm/sup -3/) for a CVL with this tube diameter.     

Dielectric Relaxation Behavior and High Tunability in Cd 2 Nb 2 O 7

Dielectric behavior of Cd 2 Nb 2 O 7 has been studied from room temperature down to 10 K with and without dc electric fields. Three dielectric relaxation modes I, II, and III were reexamined. By using the Cole - Cole equation fitting of the frequency dependence of the dielectric constant and loss of Cd 2 Nb 2 O 7 , we have obtained more precise relaxation time data, compared to the data reported in the literature. The results indicate that the relaxation time follows both the Arrhenius law and Vogel - Fulcher relation in the frequency range of 10 2 - 10 5 Hz. With increasing dc bias, the relaxation modes were suppressed and eventually eliminated. The results show a significant suppression of the dielectric constant and loss by the application of dc fields. At above 10 kV/cm, only a dielectric peak remains. The high tunability (37 - 64%) under 15 kV/cm at 5 kHz in the wide temperature range of 50 - 180 K and very low dielectric loss (0.4 - 6 2 10 m 3 )) are observed.     

基于激光诱导荧光法诊断大气压低温等离子体射流中OH自由基和O原子的时空分布

由于传统辐射光谱法无法对大气压低温等离子体射流中OH自由基和O原子进行定量检测,本文利用自主研制的纳秒脉冲激励针筒型等离子体射流装置,基于单光子和双光子激光诱导荧光法分别对OH自由基和O原子的时空分布进行诊断。结果发现,OH自由基和O原子的寿命时间分别为1ms和3ms,远大于脉冲放电持续时间;采用拟合衰减曲线法,得到OH自由基的绝对密度为1012~1013cm-3;发现离喷嘴口越远,OH自由基和O原子密度越低。然而,即使距离喷嘴口数cm的地方,仍然存在大量的OH自由基和O原子;OH自由基和O原子的密度随激励频率和脉冲电压幅值的增加而升高,随H_2O含量和O_2含量的升高而出现先增大后减小的趋势。其中,当氦气中H_2O含量为0.012%时,OH自由基密度达到最大值。当氦气中O2含量为0.5%时,O原子密度达到最大值。本文研究为调控和优化低温等离子体射流中OH自由基和O原子密度提供重要科学依据。     

A high-capacitance PZT-on-Ta2O5 memory cell with a chemically stable electrode suitable for sub-micron processing

A high-capacitance Pb (Zrx, Ti1-x)O3 (PZT)-on-Ta2O5 memory cell suitable for sub-micron processing is proposed, and an experimental capacitor of PZT (Zr/Ti= 52/48)-on-Ta2O5 with Ta electrode was prepared. The X-ray diffraction and XMA analysis of the sample showed that PZT reacted with neither Ta nor Ta2O5. The capacitor with 500 nm PZT thickness shows current density of 10-8 A/cm2 at 4MV/cm, the breakdown field of 8MV/cm, and the effective dielectric constant of 40.     

Boundary effects on the optical properties of InGaN multiple quantum wells

We examine the issues of spontaneous and piezoelectric polarization discontinuity on the optical properties of 3.0-nm-thick indium gallium nitride (InGaN) multiple quantum wells (MQWs). A quench of band-edge emission from the cap GaN layer is observed when the photoexcitation source is changed from a 355- to a 248-nm laser. The interband transitions from the InGaN wells exhibit a linear dependence on the 1) spectral blue shift of /spl sim/8.5/spl times/10/sup -18/ meV /spl middot/ cm/sup 3/ and 2) change of the internal field of /spl sim/3/spl times/10/sup -14/ meV /spl middot/ cm/sup 2/ with the injected carrier density up to N/sub inj//spl sim/10/sup 19/ cm/sup -3/ at 77 K. These observations are attributed to the redistribution of photogenerated carriers in the InGaN wells due to the polarization discontinuity at the QW interface and the surface band bending effect. By incorporating an additional boundary condition of surface Fermi-level pinning into the Poisson equation and the band-structure analysis, it is shown the emission from the InGaN-GaN MQWs is dominant by the recombination between the high-lying subbands and the screening of internal field effects.     

Charge density variation with fin width in FinFETs: an application of supersymmetric quantum mechanics

FinFETs have become of great interest since it appears that they will be implemented within the next generation of integrated circuits. One point of interest is the transition from surface inversion on the faces of the fin to bulk inversion as the fin width is reduced. We have found that a good scaling approach can give estimates of this transition, with the scaling theory based upon supersymmetric quantum mechanics. For this, a double well potential is chosen whose supersymmetric partner is the harmonic oscillator potential. The depths and the separation between the wells were varied to simulate the change in fin widths. The fraction of charge residing inside the bulk, calculated as a function of fin width and electron density, was determined by calculating overlap area between the squared wave function magnitude of any state and that of a pure bulk state. More charges reside in the bulk for any electron density as the fin width decreases. On the other hand, for a fixed fin width, increasing electron density moves charge to the surface. It was found that in a Si FinFET, bulk inversion occurs at a fin width of about 8 nm for an inversion density of 3×10¹² cm⁻².     

Ferroelectric Characteristics of Bi 4−x La x Ti 3 O 12 Thin Films Crystallized at Low Temperetures

Recently, Bi 4 m x La x Ti 3 O 12 (BLT) has received much attention because it enables low crystallization temperature with a large remanent polarization. BLT films were prepared using a metal organic decomposition technique followed by a rapid thermal annealing (RTA) and a furnace annealing. The annealing of BLT was performed in the temperature range from 550 to 700C. In particular, BLT film annealed at 600C using the RTA tool and the furnace shows good ferroelectric characteristics. The BLT film annealed at 600C exhibits a large value of remanent polarization (22 w C/cm 2 at 250kV/cm), and a low leakage current density (7 2 10 m 7 A/cm 2 at 250kV/cm), a good endurance characteristics for up to 3.2 2 10 11 cycles at 250kV/cm at 85C. From an accelerated imprint test, the lifetime of hysteresis integrity is estimated to be over 10 years at 85C. In conclusion, BLT is the one of the promising material to achieve the high density FeRAMs.     

管状空气自呼吸直接甲醇燃料电池的研制

制备了一种新型的直接甲醇燃料电池,即管状空气自呼吸直接甲醇燃料电池,采用弯曲热压法制备出管状膜电极。将管状膜电极固定在一个具有导电性能的多孔管上,制作出管状空气自呼吸直接甲醇燃料电池。燃料的供给根据使用目的不同,既可以用泵连续输送,作为固定电源,也可以采用间歇式补充甲醇溶液,作为便携式电源。同时对影响电池性能的因素,如阴极催化剂的用量,甲醇的浓度和甲醇的温度等进行了考察。阴极表面催化剂的用量可以显著地影响电池的功率密度,甲醇溶液的温度也是影响电池性能的一个关键因素。在阳极催化剂的用量为2mg/cm2Pt-Ru,阴极催化剂用量为3mg/cm2Pt,甲醇溶液浓度为4mol/L,温度为80℃时,采用空气自呼吸方式,电池的功率密度达到10mW/cm2。在管的内部一次加入4mol/L的甲醇溶液,在没有任何外围设备时,常温常压下工作,一个10cm2的管状空气自呼吸直接甲醇燃料电池可以稳定提供40mW功率的时间超过5h。     

Study on the electrical and optical properties of ITO and AZO thin film by oxygen gas flow rate

Transparent conductive oxide (TCO) thin films such as tin doped indium oxide (ITO), zinc doped indium oxide (IZO) and Al doped zinc oxide (AZO) have been widely used as transparent electrode for display. ITO and AZO thin films for display was prepared by the facing targets sputtering (FTS) system. The FTS method is called a plasma-free sputter method because the substrate is located apart from plasma. This system can deposit the thin film with low bombardment by high energetic particles in plasma such as γ-electrons, negative ions and reflected Ar atoms. ITO and AZO thin films were deposited on glass substrate at room temperature with oxygen gas flow rate and input power. And the electrical, structural and optical properties of the thin films were investigated. As a result, the resistivity of ITO, AZO thin film is 6?×?10^?4 Ω cm, 1?×?10^?3 Ω cm, respectively. And the optical transmittance of as-deposited thin films is over 80% at visible range.