Study on electroluminescence from porous silicon light-emitting diode

Porous silicon (PS) light-emitting diode (LED) with an ITO/PS/p-Si/Al structure was fabricated by anodic oxidation method. Photoluminescence (PL) of the PS LED was measured with a peak at 593 nm, and electroluminescence (EL) was measured with a peak at 556 nm under the conditions of 7.5-V forward bias and 210-mA current intensity. The spectral width of EL was measured to be about 160 nm.     

A functional identity involving elliptic integrals

We show that the following double integral

$$\begin{aligned} \int _{0}^\pi \mathrm {d}\, x\int _0^x\mathrm {d}\, y\frac{1}{\sqrt{1-\smash [b]{p}\cos x}\sqrt{1+\smash [b]{q\cos y}}} \end{aligned}$$

remains invariant as one trades the parameters p and q for \(p'=\sqrt{1-p^2}\) and \(q'=\sqrt{1-q^2}\), respectively. This invariance property is suggested from symmetry considerations in the operating characteristics of a semiconductor Hall effect device.

     

On qualitative analysis of delay systems and xΔ = f(t, x, xσ) on time scales

Here we solve two problems presented in paper [9] (C C Tisdell and A Zaidi, Basic qualitative and quantitative results for solutions to nonlinear, dynamic equations on time scales with an application to economic modelling, Nonlinear Anal. 68 (2008) 3504–3524). We study existence and uniqueness of solutions for delay systems and first-order dynamic equations of the form x ^Δ = f (t,x,x ^σ ) on time scales by using the Banach’s fixed-point theorem. Some examples are presented to illustrate the efficiency of the proposed results.     

双路输出超宽谱高功率微波驱动源Tesla变压器

为实现25 GW级双路输出超宽谱高功率微波驱动源的小型化,选择研制了一种与双筒脉冲形成线(Blumlein线)相配一体化的带有开路磁芯的Tesla变压器,作为初级脉冲功率源。进行了Tesla变压器的理论分析,利用简化的磁路模型研究了Tesla变压器初次级线圈电感等电参数的估算方法,给出了Tesla变压器磁芯截面的估算和磁芯制作方法。该Tesla变压器最大输出电压880 kV,充电时间约20 s,耦合系数约0.95,实验结果与理论设计相符。     

Direct Observation of Oxygen Vacancy Self‐Healing on TiO2 Photocatalysts for Solar Water Splitting

Oxygen vacancy (Vo) on transition metal oxides plays a crucial role in determining their chemical/physical properties. Conversely, the capability to directly detect the changing process of oxygen vacancies (Vos) will be important to realize their full potentials in the related fields. Herein, with a novel synchronous illumination X‐ray photoelectron spectroscopy (SI‐XPS) technique, we found that the surface Vos (surf‐Vos) exhibit a strong selectivity for binding with the water molecules, and sequentially capture an oxygen atom to achieve the anisotropic self‐healing of surface lattice oxygen. After this self‐healing process, the survived subsurface Vos (sub‐Vos) promote the charge excitation from Ti to O atoms due to the enriched electron located on low‐coordinated Ti sites. However, the excessive sub‐Vos would block the charge separation and transfer to TiO₂ surfaces resulted from the destroyed atomic structures. These findings open a new pathway to explore the dynamic changes of Vos and their roles on catalytic properties, not only in metal oxides, but in crystalline materials more generally.     

风险社会下我国食品安全刑法保护之完善

随着经济与科技的不断发展,现代社会迎来了经济、政治、生态、技术、化学等诸多风险,德国学者贝克将这种由科技文明带来的反映现代化的反身性认识的社会称为风险社会。在风险社会影响下,食品安全问题也凸显出不同以往的新特点,即发展变化性、经济性、社会性。在此背景下,应当对我国食品安全刑法规范进行反思,在风险社会理念下对我国食品安全的刑法保护进行合理性完善,如适当增加过失型、不作为型食品安全犯罪类型。     

Dynamic kinetic resolution of 2-oxo-3-aryl-succinates by organocatalyzed aldolization

The dynamic kinetic resolution of 2-oxo-3-arylsuccinates was achieved vial-proline-catalyzed addition of acetone in acetonitrile at room temperature, providing the desired adduct in good yield with up to 87 : 13 dr and high ee up to 99%.     

高精度激光陀螺的物理基础

分析讨论了基本物理原理在激光陀螺发展过程中所起的关键作用,从一个侧面揭示了物理学是现代技术的源泉．     

辐射诊断用的光纤传输系统

光纤频带宽、线径细、抗电磁干扰、抗腐蚀。近年来它在高能粒子物理、聚变研究、核爆和核动力学诊断等不利环境中的应用,引起了人们极大的关注。本文将扼要介绍采用光纤传输的快脉冲辐射诊断系统,并以核爆诊断为例说明这类系统的特点及与以往同轴电缆传输系统相比的优越性。