WS2 超细粉体的固相法合成

WS2 超细粉体的固相法合成;WS2;固相反应;过硫系数;高能球磨;粒度     

Mechanism of hydrodynamic separation of biological objects in microchannel devices

In this study, the separation mechanism employed in hydrodynamic chromatography in microchannel devices is analyzed. The main purpose of this work is to provide a methodology to develop a predictive model for hydrodynamic chromatography for biological macromolecules in microchannels and to assess the importance of various phenomenological coefficients. A theoretical model for the hydrodynamic chromatography of particles in a microchannel is investigated herein. A fully developed concentration profile for non-reactive particles in a microchannel was obtained to elucidate the hydrodynamic chromatography of these particles. The external forces acting on the particles considered in this model include the van der Waals attractive force, double-layer force as well as the gravitational force. The surface forces, such as van der Waals attractive force as well as the double-layer repulsive force, can either enhance or hinder the average velocity of the macromolecular particles. The average velocity of the particles decreases with the molecular radius because the van der Waals attractive force increases the concentration of the particles near the channel surface, which is the low-velocity region. The transport velocity of the particles is dominated by the gravity and the higher density enlarges the effect caused by gravity.     

多色蓝在核酸分子上的Langmuir聚集吸附

用微相吸附-光谱修正（MPASC）新技术研究核酸与多色蓝(PCB)探针分子间的相互作用，分析核酸分子内双静电膜的形成与Langmuir吸附的关联性.通过pH 7.24的介质核酸-PCB反应的光谱研究，测定了结合产物的物理化学参数：结合比1PCB:2DNA-PCB、1PCB:3RNA-PCB, 平衡常数KDNA-PCB=5.42×104， KRNA-PCB=2.82×104,摩尔吸收系数ε(DNA-PCB, 625 nm)=5.65×103（mo1－1•L ）•cm－1， ε(RNA-PCB, 625 nm)=3.85×103 （mol－1•L）•cm－1.结果表明， RNA分子仅形成约60％双螺旋结构链，核酸双螺旋每一周期的负静电沟最大聚集10个PCB分子.该吸附反应用于核酸样品测定，结果良好.     

Optimizing Multi-stage Production for an Assembly-Type Supply Chain with Unequal Sized Batch Shipments

This paper studies the multi-stage logistics and inventory problem in an?assembly-type supply chain where a uniform lot size is produced uninterruptedly with a single setup at each stage. Partial lots, or sub-batches, can be transported to next stage upon completion. Unequal sub-batch sizes at each stage follow geometric series and the numbers of sub-batches across stages are allowed to be different. Since the mainline and each branch line of an assembly-type supply chain are series-type supply chains, a model of the series-type supply chain is first established and a model of the assembly-type supply chain is subsequently developed. Optimization algorithms that determine the economic lot sizes, the optimal sub-batch sizes and the number of sub-batches for each stage are developed. The polynomial-time algorithms incorporate the optimality properties derived in the paper to find the lower and upper bounds of the solutions by constructing the solution ranges and then the optimal solutions accordingly.     

A [001]-Oriented Hittorf's Phosphorus Nanorods/Polymeric Carbon Nitride Heterostructure for Boosting Wide-Spectrum-Responsive Photocatalytic Hydrogen Evolution from Pure Water

Red phosphorus is a promising photocatalyst with wide visible-light absorption up to 700 nm, but the fast charge recombination limits its photocatalytic hydrogen evolution reaction (HER) activity. Now, [001]-oriented Hittorf's phosphorus (HP) nanorods were successfully grown on polymeric carbon nitride (PCN) by a chemical vapor deposition strategy. Compared with the bare PCN and HP, the optimized PCN@HP hybrid exhibited a significantly enhanced photocatalytic activity, with HER rates reaching 33.2 and 17.5 μmol h⁻¹ from pure water under simulated solar light and visible light irradiation, respectively. It was theoretically and experimentally indicated that the strong electronic coupling between PCN and [001]-oriented HP nanorods gave rise to the enhanced visible light absorption and the greatly accelerated photoinduced electron–hole separation and transfer, which benefited the photocatalytic HER performance.     

Penimethavone A,a flavone from a gorgonian-derived fungus Penicillium chrysogenum

A novel flavone, penimethavone A (1), possessing a rare unique methyl group at ring-B, was isolated from the fungus Penicillium chrysogenum cultured from a gorgonian Carijoa sp. collected from the South China Sea. The structure was elucidated by extensive spectroscopic analysis and by comparison with related known compound. Compound 1 showed selective and moderate cytotoxicity against cervical cancer (HeLa) and rhabdomyosarcoma cell lines with IC₅₀ values of 8.41 and 8.18 μM, respectively.     

非经典碳正离子简介

非经典碳正离子作为一种特殊的反应中间体,具有重要的理论和实际研究的意义。本文以碳正离子理论的发展为主线,以历史上非经典碳正离子(特别是降冰片基正离子)之争为中心,简要综述了Winstein、Brown和Olah三人的观点,并结合最新进展进行评述。此外,还对除降冰片基正离子之外的非经典碳正离子进行了适当的讨论。