CHARACTERIZATIONS AND RELATIONSHIPS BETWEEN OUTDOOR AND INDOOR BIOAEROSOLS IN AN OFFICE BUILDING

1.IntroductionBioaerosolsaremicroorganismsorparticles,gases,vapors,orfragmentsofbiologicalorigin(i.e.,aliveorreleasedfromalivingorganism)thatexistintheair.Bioaerosolsareeverywhereintheenvironment.Underfavorableconditions,bioaerosolsareabletogrowandpropagateonavarietyofbuildingmaterialsandindoorsurfaces,causingindoorairpollution.Therefore,owingtotheirubiquitouspresenceinnature,bioaerosolsasapollutionsourcearealmostinevitableinarangeofenclosedenvironmentsandincommunityair(Kodama&McGee,1986;Lig…     

THERMODYNAMIC AND PARTICLE-DYNAMIC STUDIES ON SYNTHESIS OF SILICA NANOPARTICLES USING MICROWAVE-INDUCED PLASMA CVD

1. Introduction1.1 Silica nanoparticles and synthesis methods Silica (SiO2) nanoparticles are widely used in industry asan active filler for polymer reinforcement, a rheologicaladditive in fluids, a free flow agent in powders, and anagent for chemical mechanical polishing during IC (inte-grated circuit) fabrication (Sniegowski & de Boer, 2000).Silica powder is also used for producing silicon carbide(Koc & Cattamanchi, 1998) or opaque silica aerosols (Leeet al., 1995). Many methods can …     

OFDMA中继系统中基于QoS保证的资源分配算法

研究了 OFDMA 中继下行链路通信系统中的动态资源分配问题,提出了一种可以保证用户最低 QoS 需求的资源分配算法.首先在简化资源优化问题的过程中,采用等功率分配方法以降低算法复杂度,然后通过拉格朗日松弛优化方法推导出了子载波分配和中继选择最优解,并在此基础上引入用户速率权衡因子,根据速率权衡因子越大的用户,越具有选择子载波和中继的优先权这一准则进行子载波分配和中继选择.仿真结果表明:新算法能够获得较高的系统容量,同时也能很好地保证不同用户的最低速率需求.     

丙烯酰氯分子的气相光解动力学

利用时间分辨傅立叶变换红外(TR-FTIR)发射光谱研究了气相中CH2=CHCOCl分子的光解动力学.观测到振动激发的光解碎片分子CO(ν≤5),HCl(ν≤6),C2H2和相应的两个光解离通道:C-Cl键断裂和HCl消除通道.通过分析转动分辨的红外发射光谱得到CO和HCl的初始振转能量态分布,由此提出CH2=CHCOCl的气相光解机理并阐明了内转换等非绝热过程在影响反应途径中的关键作用.     

Synthesis and gelation behaviors of five new dimeric cholesteryl derivatives

Five new diacid amides of di-cholesteryl L-glycinates were designed and prepared.The compounds with linkers containing 0,1, 2,3,or 4 methylene units are denoted as 1,2,3,4,and 5,respectively.Their gelation behaviors in 25 solvents were tested as novel low-molecular-mass organic gelators(LMOGs).It was shown that the length of the linker connecting the two-cholesteryl residues in a gelator plays a crucial role in the gelation behavior of the compound.1 gels 11 of the 25 solvents tested at a concentration lowe...     

四氯苯醌与嘧啶类核酸碱基的光化学氢抽取和电子转移反应

采用纳秒时间分辨的激光闪光光解实验技术,研究了四氯苯醌(TCBQ)分子与两种嘧啶核酸碱基(胸腺嘧啶和尿嘧啶)分子在355nm激发下的光化学反应动力学. 355 nm将TCBQ分子布居到激发三重态³TCBQ^*,高反应活性的³TCBQ^*与碱基分子发生两个平行的反应,氢抽取反应和电子转移反应,分别对应生成瞬态光谱上观测到的两个光反应产物TCBQH·和TCBQ·^-. 这两个反应同时生成的碱基自由基和碱基阳     

Two New Diterpene Alkaloids from the Roots of Spiraea japonica var. Acuta

Spiraea japonica L. (Rosaceae) is widely distributed in Yunnan Provence, P. R. China. Previous chemical investigations on S. japonica and its varieties have led to the report of 7 new atisane-type diterpenoids and 38 new diterpene alkaloids of atisine- and hetisine-type1-11. This paper describes the isolation and structure elucidation of two new diterpene alkaloids named spiratines A and B (1-2). Their structures were elucidated on the basis of 1D and 2D NMR experiments (HMQC, HMBC, 1…