CS2和O(3P)及N(4S)原子化学反应动力学

含硫化合物的氧化是大气化学中特别感兴趣的领域之一。研究较多的含硫化合物有SO_2、OCS和CS_2。其中O(~3P)+CS_2化学反应动力学研究在文献中已见过报导。通常认为O(~3P)和CS_2反应有三个反应通道:     

激光作用氮化铝产生的铝原子簇正负离子

为了继续关于ⅣA与ⅤA族元素二元原子簇的研究,我们最近选取了AlN为样品,在自制的装置上记录了其激光等离子体中正负离子的质谱.该装置的原理与构造已有另文介绍.实验时的激光波长是532nm,作用在样品上的激光功率密度有10~7W·cm~(-2).仪器可以同时记录正负离子的飞行时间质谱.图1所示的正负离子的质谱由连续200次采集的数据叠加而成。     

New scheme of two-channel WDM modulation with cascaded attenuated-total-reflection modulators

In this paper, we propose a two-channel WDM modulation system by cascading attenuated-total-reflection (ATR) modulators. This system is free from channel demultiplexing and multiplexing elements. Two independent light signals with 20 nm channel spacing are experimentally demonstrated with modulation crosstalk less than −20 dB between the channels.     

Energy reduction: a technique for seed-injection locking of single-axial-mode Q-switched Nd:YAG laser

A new technique for seed-injection locking of single-axial-mode (SAM) Q-switched Nd:YAG laser is reported. The technique called energy reduction (ER) is utilized when SAM operation is locked to design its feedback scheme. This method ensures long-term 100% seed-injection locking performance and the pulsed SAM output energy can reach as high as 200 mJ. Both temporal and spatial interferometric experiments have been executed to confirm the SAM oscillation.     

Backward/Hopf bifurcations in SIS models with delayed nonlinear incidence rates

The classical SIS model with a constant transmission rate exhibits simple dynamic behaviors fully determined by the basic reproduction number. Behavioral changes and intervention measures influenced by the level of infection, likely with a time lag, require the transmission rate to be a nonlinear function of the total infectives. This nonlinear transmission, as shown in this paper via a combination of qualitative and numerical analysis, can generate interesting dynamical behaviors at the population level including backward and Hopf bifurcations. We conclude that sustained infections and periodic outbreaks can be consequences of delayed changes in behaviors or human intervention.      

Preparation and electrochemical properties of V<Subscript>2</Subscript>O<Subscript>5</Subscript> submicron-belts synthesized by a sol–gel H<Subscript>2</Subscript>O<Subscript>2</Subscript> route

One-dimensional (1D) submicron-belts of V₂O₅ have been prepared by a sol–gel route using V₂O_5, H₂O₂ and aniline as starting materials. Thermogravimetric and differential thermal analysis, X-ray diffraction, Fourier transform infrared spectroscopy and scanning electron microscopy were employed to characterize the samples. Electrochemical behaviors as cathode material in rechargeable lithium-ion batteries were investigated by galvanostatic charge–discharge measurement and cyclic voltammeter. The results showed that the synthesized V₂O₅ appeared to be submicron-belts and orthorhombic structure. The V₂O₅ submicron-belts exhibited a high initial discharge capacity of 346 mAh/g and stayed 240 mAh/g after 20 cycles at 0.1 C discharge rate in the potential region 1.8–4.0 V.     

约束非线性ι1问题的光滑近似算法

针对约束非线性ι1问题不可微的特点,提出了一种光滑近似算法.该方法利用“ “函数的光滑近似函数和罚函数技术将非线性ι1问题转化为无约束可微问题,并在适当的假设下,该算法是全局收敛的.初步的数值试验表明算法的有效性.     

Preparation and anti-tumor evaluation of polyactin A microparticles from supercritical CO2 processing

This paper reports the use of a coating process based on supercritical fluid technology to prepare a solvent-free microparticles, loaded with a polymannopeptide (polyactin A, PAA) for enhancing optimal host response in cancer immunotherapy. Microparticles were characterized as regards their morphology, drug content and in vitro release. A prolonged release of the PAA had been achieved over a 24 h period from microparticles coated with the lipidic compound, which produced a more homogeneous, film-forming coating. Furthermore, it was shown that PAA did not undergo any degradation under the supercritical conditions used in the coating process. In vitro immunoactivity and anti-tumor effect analysis results showed that the PAA microparticle could efficiently trigger the induction of cytotoxic T lymphocytes (CTLs) in a sustained manner.     

Spherical particles from tetraorthosilicate (TEOS) sol–gel process with dimethyldiethoxysilane (DDS) and diphenyldiethoxysilane (DPDS) addition

In acid-catalyzed tetraorthosilicate(TEOS) sol–gel process, dimethyldiethoxysilane (DDS) and diphenyldiethoxysilane (DPDS) were added to obtain TDP spherical particles which, according to scanning electron microscopy (SEM) and thermogravimetric (TG) analysis, showed smooth surface and good thermal stability. The formation of the final TDP particles are discussed following three steps, which were much related with the formation of TEOS oligomer and TEOS–DDS reactive skeleton.     

Persistence of wavefronts in delayed nonlocal reaction-diffusion equations

We develop a perturbation argument based on existing results on asymptotic autonomous systems and the Fredholm alternative theory that yields the persistence of traveling wavefronts for reaction-diffusion equations with nonlocal and delayed nonlinearities, when the time lag is relatively small. This persistence result holds when the nonlinearity of the corresponding ordinary reaction-diffusion system is either monostable or bistable. We then illustrate this general result using five different models from population biology, epidemiology and bio-reactors.