Crystallization of binary carboxylic acids characterized with streaming potential measurement

The streaming potential of supersaturated solution of binary carboxylic acids, which have even carbon atoms, was determined to characterize crystallization under different temperatures. The value of the streaming potential was related to the type and solubility of the acids and the starting temperature of crystallization, and was easily influenced by the pressure difference of the liquid or the rate of temperature decline. When the temperature was declined to the point where a crystal nucleus appeared, the streaming potential reached the minimum. Thereafter, as the temperature was sequentially lowered, some minicrystals grew, and the streaming potential presented an ascendant tendency. The higher the starting temperature of the acids saturated solution, the higher is the temperature corresponding to the streaming potential minimum. The less the carbon atoms in the acids and the greater the solubility of the acids are, the higher is the temperature of the streaming potential minimum. Copyright © 2007 John Wiley & Sons, Ltd.     

Li/Garnet Interface Stabilization by Thermal-Decomposition Vapor Deposition of an Amorphous Carbon Layer

Applying interlayers is the main strategy to address the large area specific resistance (ASR) of Li/garnet interface. However, studies on eliminating the Li₂CO₃ and LiOH interfacial lithiophobic contaminants are still insufficient. Here, thermal-decomposition vapor deposition (TVD) of a carbon modification layer on Li_6.75La₃Zr_1.75Ta_0.25O₁₂ (LLZTO) provides a contaminant-free surface. Owing to the protection of the carbon layer, the air stability of LLZTO is also improved. Moreover, owing to the amorphous structure of the low graphitized carbon (LGC), instant lithiation is achieved, and the ASR of the Li/LLZTO interface is reduced to 9 Ω cm². Lithium volatilization and Zr⁴⁺ reduction are also controllable during TVD. Compared with its high graphitized carbon counterpart (HGC), the LGC-modified Li/LLZTO interface displays a higher critical current density of 1.2 mA cm⁻², as well as moderate Li plating and stripping, which provides enhanced polarization voltage stability.     

血清中葡萄糖含量的测定方法及其研究进展

阐述了血清中葡萄糖的检测在临床诊断研究方面的重要意义,较全面地综述了血清葡萄糖常用的检测方法及研究进展。     

Fully quantum mechanical energy optimization for protein-ligand structure

We present a quantum mechanical approach to study protein-ligand binding structure with application to a Adipocyte lipid-binding protein complexed with Propanoic Acid. The present approach employs a recently develop molecular fractionation with a conjugate caps (MFCC) method to compute protein-ligand interaction energy and performs energy optimization using the quasi-Newton method. The MFCC method enables us to compute fully quantum mechanical ab initio protein-ligand interaction energy and its gradients that are used in energy minimization. This quantum optimization approach is applied to study the Adipocyte lipid-binding protein complexed with Propanoic Acid system, a complex system consisting of a 2057-atom protein and a 10-atom ligand. The MFCC calculation is carried out at the Hartree-Fock level with a 3-21G basis set. The quantum optimized structure of this complex is in good agreement with the experimental crystal structure. The quantum energy calculation is implemented in a parallel program that dramatically speeds up the MFCC calculation for the protein-ligand system. Similarly good agreement between MFCC optimized structure and the experimental structure is also obtained for the streptavidin-biotin complex. Due to heavy computational cost, the quantum energy minimization is carried out in a six-dimensional space that corresponds to the rigid-body protein-ligand interaction.     

气相色谱-质谱分析血清葡萄糖的前处理方法研究

用气相色谱-同位素稀释质谱法(GC-ID/MS)测定血清葡萄糖,需要对血清样品进行前处理,为确保测定结果的准确性,比较了乙醇、丙酮、乙腈沉淀及微过滤4种去除蛋白的方法.将用上述4种方法处理的血清样品进行衍生,采用GC-ID/MS测定,得到其精密度、相对回收率和绝对回收率,加以比较.结果表明:4种方法中,乙醇去除血清中蛋白的效果最佳.     

Precursor-directed fungal generation of novel halogenated chaetoglobosins with more preferable immunosuppressive action

Precursor-fed cultivation of endophytic Chaetomium globosum 1C51 afforded nine novel "unnatural" halogenated chaetoglobosins including those with more preferable immunosuppressive activity.     

数字离子阱质谱仪低质量截止值的改进方法

本研究在实验室自制的线形数字离子阱质量分析器上,通过改变数码电源的频率扫描方式,在CID过程中,通过扫描数字束缚方波电源的频率和数字激发方波的频率实现母体解离。例如对于利血平母体离子,当将离子数字束缚方波频率从500 kHz扫描到560 kHz,可以测量到低质荷比的碎片离子,成功实现了串级质谱分析的低质量碎片离子的分析。通过与利血平三重四极质谱串级质谱分析实验结果的比较,发现可以在数字离子阱质谱仪上获得与三重四极质谱相同的串级质谱测量结果。结果表明,本方法可以用于低质量离子的测量,克服了传统离子阱质谱进行串级质谱分析的一个主要难点,显著提高数字离子阱质谱的性能。     

快速腔长扫描光腔衰荡光谱仪及其中痕量气体测量中的应用

基于PZT快速腔长扫描技术和可调谐连续DFB激光器,搭建了一套快速腔长扫描光腔衰荡光谱探测装置,通过PZT快速腔长扫描实现激光单纵模与光腔纵模的模式匹配与破坏,以完成腔内光信号的独立衰减以及对此衰减过程快慢的测量。实验表明该装置不仅测量灵敏度高达10^-9量级,而且稳定性强,装置简单且易于操作。通过对CH₄气体在1653.72 nm 附近的吸收光谱测量,并用HITRAN数据库模拟校准,验证了该装置的定量测量能力。利用该装置通过固定激光波长测量吸收峰中心值方法对大气中CH4气体含量变化进行了探测。     

二次系统奇点的分支问题

本水文研究了(Ⅱ)和(Ⅲ)类的二次系统奇点的分支,并回答了[1]中提出的问题.