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.     

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...     

新型卟啉及其锌配合物的合成与性质研究

设计合成了一种新型的不对称卟啉(5,10,15-三苯基-20-{4-[6′-(4″-o-亚水杨基)-苯亚胺基]己氧基}苯基卟啉)及其锌配合物,并用¹H NMR、质谱及紫外-可见光谱进行表征。采用紫外-可见光谱滴定法,对锌卟啉与4种咪唑类小分子间的轴向配位反应热力学性质的研究表明：反应为放热、熵增加过程,4种咪唑类配体对锌卟啉的配位平衡常数按K^Θ(2-MeIm)>K^Θ(N-MeIm)>K^Θ(2-Et-4-MeIm)>K^Θ(Im)顺序依次减小。运用Z-扫描技术研究了新型卟啉及其锌配合物的非线性光学性质。     

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…     

Crystal and Molecular Structure of N-(1-Ethoxycarbonyl- ethyl)1-Ethoxycarbonylmethyl-3-ethyl-1,2,3,4- tetrahydro-4-oxo-1,3,2-benzodiazaphosphorin- 2-carboxamide 2-Oxide

1 INTRODUCTIONOrganophosphorus compounds are ubiquitous in nature and they have broad applications in the fields of agriculture and medicine. During the past two decades, (-ketophosphonates and their derivatives have attracted considerable attention because these compounds are endowed with special physical, chemical and pharmacological properties due to the proximity of the carbonyl and the phosphoryl groups[1～6]. For example, it is well known that phosphonoformic acid (PFA) is effectiv…