Last Passage Time Statistics for Barrier-Crossing Processes

A concept of mean last passage time at the saddle point is proposed in order to compute both the lifetime and the escape rate of a particle in a metastable potential, where the backstreaming across the saddle point is taken into account. It is shown that the mean oscillating time around the saddle point is the longest one among all the time scales at high temperatures and the inverse of the mean last passage time at the saddle point is more close to the steady escape rate.     

Isotope Effects in the Electrochemical Reduction of Oxalic Acid-D2 and Benzoic Acid-D

Abstract

The electrochemical reduction of model carboxylic acid at lead cathodes in deuterated media was studied for potential use in the synthesis of special deuterated compounds.

Oxalic acid-d₂ in D₂O gives good yields of glyoxylic acid-d₂. An unexpected large isotope effect of 5.3 ± 1.7 was found in this reaction, leading to significant depletion of deuterium content in the aldehyde group.

Benzoic acid-d in CD₃OD/diluted D₂SO₄ yields benzyl alcohol-d, 7,7-d₂. The isotope effect of 2.4 ± 1.0 is within the expected range. No deuterium is incorporated into the aromatic nucleus. Essentially unlabelled benzyl alcohol is obtained in CD₃OH/dil. H₂SO₄.     

外形分析-拟合求导法测接触角

在外界来流作用下,液滴在固体表面上呈现周期性振荡特性,接触角的动态变化是表征该过程特性的重要参数, 传统方法不适用此接触角测量。在分析常用接触角测量方法的基础上,提出外形分析-拟合求导法测量动态接触角,同经典测量方法对比表明,外形分析-拟合求导法可很好地满足测量精度要求。     

Performance Test of CW 300?GHz Gyrotron FU CW I

A 300 GHz CW gyrotron FU CW I has been developed and installed in the Research Center for Development of Far-Infrared Region, University of Fukui as a power source of a high frequency material processing system. Its performance was tested and the maximum power of 1.75 kW / CW has been attained at the beam voltage of 15 kV and the beam current of 1A. The maximum window power efficiency of 15.5% has been obtained at the cathode voltage slightly lower than 15 kV. This gyrotron is designed to deliver a Gaussian beam after mode conversion from the oscillation mode TE_22,8 in the cavity with a complex of an internal radiator and beam shaping mirrors. The detailed measurement with an infrared camera has confirmed that a Gaussian beam is radiated when the magnetic field strength B _c at the cavity is adjusted at a proper value. However, within a range of B _c , the output power is emerged into multiple directions, which suggests simultaneous oscillation of competing cavity modes.     

扫描电化学显微镜在功能材料分析中的应用

扫描电化学显微镜是一种扫描探针技术,利用微电极检测发生在固／液、液／液或者气／液界面反应物或者反应产物的连续变化。这里将对该技术原理进行详细说明。过去我们工作主要都集中在固定化酶的活性成像。最近研究的领域开始拓展到与能源转变相关材料上,如染料敏化太阳能电池和（生物）燃料电池的氧气催化还原。起初的尝试已经扩展到如何扩宽研究材料的范围和成像模式的应用范围。扫描电化学显微镜的反馈和产生～收集模式已被用于研究染料敏化太阳能电池半导体／电解质界面的光激发染料阳离子再生过程。现在开始关注更多的与太阳能的再生,燃料电池或染料敏化太阳能电池相关的复杂反应,这些复杂的反应包括外部质量传输过程、内部质量和电荷传输过程、多孔物质反应中心的本身活性等。     

对巯基苯甲酸在电化学沉积金膜表面的SERS研究

SERS技术由于具有高灵敏度的表面效应,能够检测吸附在金属表面的单分子层或亚单分子层的分子,并能给出丰富的分子结构信息,因而己被广泛应用于界面科学以及定性和定量分析科学领域之中。本文在制备电化学沉积金纳米薄膜的基础上,利用扫描电镜观察金纳米薄膜的形貌,通过分析对巯基苯甲酸在电化学沉积金膜表面的SERS光谱,研究对巯基苯甲酸在金纳米薄膜表面的吸附方式。由SERS光谱分析,我们推断出对巯基苯甲酸可能通过羧基和S原子共同作用吸附在金纳米颗粒表面,且苯环平面可能与金薄膜表面成一定倾斜角。     

Internal flow of acoustically levitated drops undergoing sectorial oscillations

We present the experimental observation and theoretical analysis of fluid flow in acoustically levitated water drop undergoing sectorial oscillations. The fluid always flows between the extended sections and the compressed sections. The magnitude of fluid velocity decreases from the equatorial fringe to the centre of levitated drop. The maximum fluid velocity is 60-160 mm/s and the Reynolds number of the oscillations is estimated to be 137-367. The internal flow of the drop is analyzed as potential flow, and the fluid velocity is found to be horizontal. In the equatorial plane, the calculated stream lines and velocity profiles agree well with the experimental observations.     

Probing CPT violation in neutrino oscillation: A three flavor analysis

We have studied CPT violation in neutrino oscillation considering three flavor framework with matter effect. We have constructed a new way to find the oscillation probability incorporating CPT violating terms without any approximation. Then CPT   violation with atmospheric neutrinos for a magnetized iron calorimeter detector considering the muons (directly measurable with high resolution) of the charge current events has been studied for zero and nonzero θ₁₃${\theta }_{13}$ values. It is found that a potential bound of δb₃₂?6×¹⁰⁻²⁴ GeV$\delta b_{32}?6\times {10}^{-24}\text{GeV}$ at 99% CL can be obtained with 1 Mton.year exposure of this detector; and unlike neutrino beam experiments, there is no possibility to generate ‘fake’ CPT violation due to matter effect with atmospheric neutrinos. The advantages of atmospheric neutrinos to discriminate CPT violation from CP violation and nonstandard interactions are also discussed.     

铂黑修饰酶电极测定胆碱

利用电化学方法在玻碳电极上均匀沉积亚微米粒度铂黑并进而修饰一层胆碱氧化酶膜,制成了胆碱酶电极。以计时电流法测定氯化胆碱,检测下限为 ７．４ μｍｏｌ／Ｌ,线性范围２．４×１０－２～ １．０ ｍｍｏｌ／Ｌ,重现性好,使用寿命较长。