Analytical potential energy function and spectroscopy parameters for B~1Π state of KH

Multi-reference configuration interaction is used to produce potential energy curves(PECs) for the excited B1Π state of KH molecule.To investigate the correlation effect of core-valence electrons,five schemes are employed which include the different correlated electrons and different active spaces.The PECs are fitted into analytical potential energy functions(APEFs).The spectroscopic parameters,ro-vibrational levels,and transition frequencies are determined based on the APEFs and compared with available experimental and theoretical data.The molecular properties for B1Π obtained in this letter,which are better than those available in literature,can be reproduced with calculations using the suitable correlated electrons and active space of orbitals.     

Global Existence and the Optimal Decay Rates for the Three Dimensional Compressible Nematic Liquid Crystal Flow

The present paper is dedicated to the study of the Cauchy problems for the three-dimensional compressible nematic liquid crystal flow. We obtain the global existence and the optimal decay rates of smooth solutions to the system under the condition that the initial data in lower regular spaces are close to the constant equilibrium state. Our main method is based on the spectral analysis and the smooth effect of dissipative operator.     

Solvothermal synthesis of PbTe/SnTe hybrid nanocrystals

PbTe/SnTe hybrid nanocrystals with designed shape, chemical composition and narrow size distribution were synthesized by an efficient solvothermal approach. This approach enables mass and economical synthesis of PbTe-based nanocrystals. The organic ligands were completely removed by pretreatment with a super-hydride solution, making it possible to fabricate fully dense and robust thermoelectric devices with increased electrical conductivity.     

Theoretical Prediction on the Germylenoid HB=GeLiF and Its Insertion Reaction with R-H（R = F,OH,NH_2）

In the present work we investigated a novel triplet ground-state germylenoid HB=GeLiF as well as its insertion reactions with RH(R = F,OH and NH2) using the DFT B3LYP and QCISD methods for the first time.Geometry optimization calculations show that the triplet HB=GeLiF has three equilibrium structures,in which the four-membered ring structure is the most stable with the lowest energy.All mechanisms of the three insertion reactions of germylenoid HB=GeLiF with RH(R = F,OH,and NH2) are identical to each other.Based on the calculated results,it is concluded that under the same conditions the insertion reactions should occur easily in the order of H-F > H-OH > H-NH2.In THF solvent the insertion reactions get more difficult than in the gas phase.     

Theoretical study of the interaction between LiNH2 and HMgH

The lithium bond between HMgH and LiNH₂ has been predicted and characterized with quantum chemical calculations at the MP2/6‐311++G(d,p) level. Upon formation of the lithium bond, both the Mg? H and Li? N bonds are stretched. The Li? N bond undergoes a red shift, whereas the Mg? H bond exhibits a blue shift. The lithium‐bonded complex is controlled mainly by electrostatic and polarization interactions. The binding energy of HMgH with LiNH₂ is computed to be 12.47 kcal/mol. The binding of the two molecules is enhanced by the substitution with the methyl group in the Li acceptor, whereas it is weakened by the replacement with whether the electron‐withdrawing group such as F, Cl, CN, NC, or the electron‐donating group (OH and HN₂). A negative cooperativity is present in the ternary system of 2LiNH₂ and HMgH. The polarization interaction plays an important role in the negative cooperativity. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2011     

Ultrasound-Assisted Dispersive Liquid�CLiquid Microextraction Combined with Low Solvent Consumption for Determination of Polycyclic Aromatic Hydrocarbons in Seawater by GC�CMS

Ultrasound-assisted dispersive liquid?Cliquid microextraction (USA-DLLME) with low solvent consumption was demonstrated for gas chromatography-mass spectrometry (GC?CMS) determination of 16 typical polycyclic aromatic hydrocarbons (PAHs) in seawater samples. Factors affecting the extraction process, such as extraction and dispersive solvent, phase ratio, temperature, extraction and centrifugation time, were investigated thoroughly and optimized. The linear range was 20?C2,000 ng L^?1 except for acenaphthylene (Acy) at 10?C2,000 ng L^?1 and phenanthrene (Phe), fluoranthene (Flu) and pyrene (Py) all at 5?C2,000 ng L^?1. Enrichment factors (EFs) ranging from 722 to 8,133 were obtained, achieving limits of detection at 1.0?C10.0 ng L^?1. The method attained good precision (relative standard deviation, RSD) from 3.4 to 14.2% for spiked 50 ng L^?1 individual PAHs standards. Method recoveries were in the range 87?C124% and 70?C127% for spiked samples from simulated seawater and beach seawater, respectively. The proposed USA-DLLME helped to obtain about 1.1?C10 times higher EFs in a minimum amount of solvent and in less time than traditional DLLME.     

基于Schiff-base结构化合物载体的汞离子选择性电极的制备与表征

高产率合成了一种新的Schiff-base结构化合物,并将其表征为高选择性聚合物膜汞离子选择性电极载体。考察了不同增塑剂及离子交换剂对膜电极响应性能的影响,在最佳膜组分条件下测得该电极对汞离子的线性响应范围为1.0×10-6~3.0×10-4mol/L,响应斜率为(29.3±0.3)mV/dec,检出限为2.6×10-7mol/L;该电极响应速率快(小于12 s),可在较宽的pH范围内(pH2.8~5.6)使用,且其它常见碱金属、碱土金属以及过渡金属离子对该测试电极的干扰小;可准确检测自来水中汞离子的浓度。     

Atom transfer radical polymerization with activators regenerated by electron transfer of acrylonitrile from silica nanoparticles,and adsorption properties of the resin for Hg2+ after amidoximation with hydroxylamine

Polyacrylonitrile (PAN) was grafted from surfaces of chloro‐modified silica‐gel with their surface chlorines as initiation sites, using an iron (III)‐mediated surface‐initiated atom transfer radical polymerization (ATRP) with activators regenerated by electron transfer (SI‐ARGET ATRP) method. The graft reaction exhibits first‐order kinetics with respect to the polymerization time in the low‐monomer‐conversion stage. The conversion of monomer (C%) and the percentage of grafting (PG%) increased with increasing of the polymerizing time and reached 23 and 730% after a polymerizing time of 24 hr, respectively. Hydroxylamine (NH₂OH·HCl) was used to modify the cyano groups of SG‐g‐PAN to obtain amidoxime (AO) groups. The AO SG‐g‐PAN was used to remove Hg²⁺. The adsorption kinetics indicated that the pseudo‐second‐order model was more suitable to describe the adsorption kinetics of AO SG‐g‐PAN for Hg²⁺. The adsorption isotherms demonstrated that Langmuir model was much better than Freundlich model to describe the isothermal process. Copyright © 2010 John Wiley & Sons, Ltd.     

Determination of Hydrocortisone in Cosmetics by CdSe/CdS Quantum Dots-Based Fluoroimmunoassay Using Magnetic Fe3O4/Au Nanoparticles as Solid Carriers

This work demonstrated the feasibility of detecting hydrocortisone in cosmetics using a novel CdSe/CdS quantum dots‐based competitive fluoroimmunoassay with magnetic core/shell Fe₃O₄/Au nanoparticles (MCFN) as solid carriers. Hydrocortisone antigen was labeled with the synthesized core/shell CdSe/CdS quantum dots (QDs) to form the antigen‐QDs conjugate. Meanwhile, hydrocortisone antibody was incubated with MCFN and the immobilized antibody was obtained. The immobilized antibody was then mixed sequentially with hydrocortisone and a slightly excess amount of the QDs‐labeled hydrocortisone antigen, allowing their competition for binding with the antibody immobilized on MCFN. The bound hydrocortisone and the antigen‐QDs conjugates on MCFN were removed subsequently after the mixture was applied to a magnetic force. The analyte concentration was obtained by measuring the fluorescence intensity of the unbound hydrocortisone antigen‐QDs conjugates. The proposed method was characterized by simplicity, rapidity, and high sensitivity with a wide linear working range of 0.5 to 15000 pg·mL^?1 and a low detection limit of 0.5 pg·mL^?1. The proposed method was successfully applied to the determination of hydrocortisone in cosmetics with satisfactory results.     

铽-环丙沙星-SDS敏化荧光猝灭法检测雷公藤红素

在pH=9.26的氨-氯化铵缓冲溶液中,铽Ⅲ与环丙沙星反应形成络合物,而后加入十二烷基硫酸钠(SDS)形成了三元体系,其最佳激发、发射波长分别为λex= 330nm、λem=545 nm.在该反应体系中加入适量雷公藤红素溶液,铽Ⅲ与环丙沙星络合物的激发、发射波长位置不变,但荧光强度有规律下降.利用这一现象,建立了测定雷...