有机分子的自洽场分子轨道从头计算的通用程序和C,H基组的选择

本文介绍一个适用于中小有机分子的自洽场分子轨道(SCFMO)从头计算通用程序,并对各种C、H基组作了比较研究,提出一个新的最小原子轨道基组。用它试算甲烷分子的电子结构,仅用9个原子轨道(AO)和41个GTO,得到的分子总能量为E=-40.1662hartree,比STO-KG的结果为优。例如STO-6G用9AO-54GTO得到E=-40.1011hartree。甚至比国际通用的Gaussian-70程序所采用的4-31G双ζ基组也有改进,后者用17AO-36GTO得到E=-40.1395hartree。此外,还在S.B.双ζ基组的基础上,在C-H键中间外加浮动键轨道,得到E=-40.1930hartree。     

Investigation of the thermal performance in lithium-ion cells during polyformaldehyde nail penetration

Journal of Thermal Analysis and Calorimetry - The nail penetration test on lithium-ion cells with a tungsten steel nail can cause significant heat sinking to the nail. In this work, a...     

第三届全国环境力学研讨会简介

近半个世纪以来,由人类社会采取高投入、高消耗的发展模式所导致的综合性的环境问题频繁发生,越来越危及人类自身的健康和生存安全,成为影响社会和经济发展的重要因素.     

Chelation-mediated in-situ formation of ultrathin cobalt (oxy) hydroxides on hematite photoanode towards enhanced photoelectrochemical water oxidation

In this work,a facile chelation-mediated route was developed to fabricate ultrathin cobalt(oxy)hydroxides(CoOOH)nanosheets on hematite photoanode(Fe₂O₃).The route contains two steps of the adsorption of[Co-EDTA]^2-species on Fe₂O₃ nanorod array followed by the hydrolysis in alkaline solution.The resulting CoOOH/Fe₂O₃ exhibits a remarkably improved photocurrent density of 2.10 mA cm^-2 at 1.23 V vs.RHE,which is ca.2.8 times that of bare Fe₂O₃.In addition,a negative shift of onset potential ca.200 mV is achieved.The structural characterizations reveal the chelate EDTA plays important roles that enhance the adsorption of Co species and the formation of contact between CoOOH and Fe₂O₃.(Photo)electrochemical analysis suggests,besides providing active sites for water oxidation,CoOOH at large extent promotes the charge separation and the charge transfer via passivating surface states and suppressing charge recombination.It also found CoOOH possesses some oxygen vacancies,which could act as trapping centers for photogenerated holes and facilitate the charge separation.Intensity modulated photocurrent spectroscopy(IMPS)shows that,under low applied potential the water oxidation mainly occurs on CoOOH,while under high applied potential the water oxidation could occur on both CoOOH and Fe₂O₃.The findings not only provide an efficient strategy for designing ultrathin(oxy)hydroxides on semiconductors for PEC applications but also put forward a new insight on the role of CoOOH during water oxidation.     

用HPLC测定虫草酒中的黄芪甲甙

为了控制虫草酒质量,采用高效液相色谱（ＨＰＬＣ）法以ＹＷＧ－Ｇ１８为固定相,乙腈－水（１：２）＋０．１５％磷酸为流动相,ＵＶ检测,波长为２０５ｎｍ。测定了虫草酒中黄芪甲甙的含量,方法简便,结果准确,回收率分别为９２．３７％～９７．２７％。ＲＳＤ为１．４７％,能满足质量标准控制要求。     

小儿肾病综合征患儿血中锌,铜,铁,钙,铅的研究

为探讨小儿肾病综合征患儿血中锌,铜,铁钙,铅的变化规律,对６０例小儿肾病综合征和６０例正常儿童全血中锌,铜,铁、钙,铅含量进行了对比观察。结果表明,小儿肾病综合征患儿以上５种元素均比正常儿童降低,     

水合苯并—15—冠—5四溴合铟(Ⅲ)酸钠(NaInBr_4)_2(C_(14)H_(20)O_5)_3·2H_2O的晶体结构

本文报道了在乙醇—氯仿混合溶剂中首次获得组份为(NaInBr_4)_2(C_(14)H_(20)O_5)_3·2H_2O的晶体配合物.用元素分析确定了其组份.通过红外光谱的研究证实配合物晶体中的阳离子与醚氧原子及水分子发生了配合作用。 用X-射线衍射法测定了配合物的晶体结构,晶体属单斜晶系,M=1755.3,a=14.393(8)A,b=28.494(9)A,c=15.191(8)A,β=96.63(5)°,V=6189A~3’,D_c=1.88g·cm~(-3),Z=4,空间群为C_(2h)~5——P2_1/n。晶体结构研究表明不对称单位中包含两个配阳离子Na~(+)(B15C5)(B15C5)代表C_(14)H_(20)O_5分子)。两个配阴离子InBr_4~-、两个H_2O分子和一个未被金属离子配合的B15C5分子。配合物的晶体结构测定结果对于阐明与该晶体相对应的萃取体系In(Ⅲ)/NaBr/B15C5—1,2C_2H_4Cl_2的萃取机理提供了理论依据。     

Turn-on fluorometric immunosensor for diethylstilbestrol based on the use of air-stable polydopamine-functionalized black phosphorus and upconversion nanoparticles

The preparation of air-stable black phosphorus (BP) is challenging because atomic layers of BP degrade rapidly on exposure to oxygen. A strategy is presented for the synthesis of BP functionalized with polydopamine (PDA/BP). Dopamine was self-polymerized to yield polydopamine (PDA) which then was used to coat the surface of BP. PDA can be easily reduced and this prevents BP degradation. PDA/BP also is a viable matrix for the adsorption of proteins due to the presence of functional groups. Without any chemical activation, diethylstilbestrol (DES)-specific monoclonal antibody was adsorbed on the PDA/BP surface. PDA/BP quenches the fluorescence antigen-modified NaYF₄:Yb,Ho,Nd upconversion nanoparticles (UCNPs; photoexcited at 808 nm) via specific immuno recognition. Exposure to DES causes the dissociation of UCNP from the PDA/BP surface and fluorescence at 475, 525, 545 and 660 nm to recover. This is due to the DES competition with antigen for binding to the antibody. Based on this competitive immuno mechanism, a turn-on fluorometric immunoassay was constructed. It has a response that covers the 0.1 to 1000 ng mL^?1 DES concentration range with a detection limit of 83 pg mL^?1. This method was successfully applied to the determination of DES in spiked food and human urine samples.

Open image in new window

Graphical abstract Air-stable polydopamine-functionalized black phosphorus was obtained by modification of black phosphorus with polydopamine and then was coupled with specific monoclonal antibody. Combined with antigen-modified upconversion nanoparticles, a turn-on fluorometric immunoassay was constructed to detect diethylstilbestrol.

     

冠醚萃取苦叶酸钪与配合物的晶体结构研究

研究了苯并１５冠５（Ｂ１５Ｃ５）和二苯并１８冠６（ＤＢ１８Ｃ６）萃取苦味酸钪的萃取平衡。在ｐＨ２～３，用斜率法确定了两种萃合物的组成，并由此计算了它们的表观萃取平衡常数。通过苯并１５冠５苦味酸钪配合物的合成、表征及晶体的结构测定，讨论了萃取机理。     

Studies on biotin–avidin indirect conjugated technology for a piezoelectric DNA sensor

Because of their high sensitivity, piezoelectric sensor techniques are extremely useful for environmental or clinical analysis. We developed a piezoelectric crystal DNA biosensor for the detection of the hybridization reaction based on the self-assembled monolayer technology and biotin–avidin system. 3,3′-Dithiopropionic acid was applied to form a self-assembled monolayer (SAM) on the gold surface of the quartz crystal. Avidin was coated on the gold electrode conjugated with 1-ethyl-3-[3-(dimethylamino)propyl]-carbodiimide (EDC) and N-hydroxysuccinimide (NHS), and then biotinylated nucleotide acids were immobilized on the gold electrode surface through the specific interaction of biotin and avidin. Our results indicated that, using this immobilization method, the piezoelectric DNA sensor shows a higher sensitivity and specificity in detecting the hybridization reaction. The sensor can be used repeatedly by electrode regeneration.