Fe_3O_4 nano-whiskers by ultrasonic-aided reduction in concentrated NaOH solution

Fe 3 O 4 nano-whiskers were synthesized via ultrasonic-aided reduction of FeCl 2 ·4H 2 O with N 2 H 4 ·H 2 O in concentrated NaOH solution. Phase identification and morphology observation were conducted by X-ray diffraction (XRD) analysis, transmission electron microscopy (TEM) and field emission scanning electron microscopy (FE-SEM). Face scanning energy dispersive spectrum (face scanning EDS) and two-dimensional fast Fourier transform (2DFFT) for element distribution were carried out for confirming compos...     

一种新的库仑微水滴定仪的设计方法

在传统微库仑滴定仪原理的基础上，利用８７５１单片机和微机，采用对电解电流时间调制的方法以及测量精度为准则判断滴定终点，从而大大地提高了仪器的测量精度和重复性。     

耐尔蓝分光光度法间接测定铵

以耐尔蓝为显色剂，采用分光光度法进行铵的测定。选择了ＮａＯＨ碱解蒸馏分离氨的条件，探讨了表面活性剂ＯＰ，ＳＤＳ增敏增溶作用，分别测定了雨水，土壤，绿叶中铵含量，结果满意。     

超浓乳液聚合制备PU/PS的SIPN粉状树脂研究

将聚氨酯予聚体 (PU ) 苯乙烯 (St)的复合体系 ,用超浓乳液聚合方法制备了半互穿聚合物网络(SIPN)复合聚合物 ,得到了用聚氨酯予聚体改性的聚苯乙烯 (PU/PS)SIPN粉状树脂 .研究了分散相的比例(α)和聚合温度对聚合稳定性及聚合转化率 -时间的关系 ;测定了聚合物胶乳粒子的大小、形态 ,玻璃化温度 ,动态力学性能等 .结果表明 ,超浓乳液聚合较之本体聚合具有较高的聚合速率 ,容易控制所制备的胶乳粒径 ,能够制得PU/PS复合聚合物的SIPN粉状树脂 .该粉状树脂便于加工 ,具有良好的强韧性 ,有利于扩大应用     

Simultaneous determination of UV filters and polycyclic musks in aqueous samples by solid-phase microextraction and gas chromatography–mass spectrometry

A simple, precise and accurate method for the simultaneous determination of four UV filters and five polycyclic musks (PCMs) in aqueous samples was developed by solid-phase microextraction coupled with gas chromatography–mass spectrometry (SPME-GC–MS). The operating conditions affecting the performance of SPME-GC–MS, including fiber thickness, desorption time, pH, salinity, extraction time and temperature have been carefully studied. Under optimum conditions (30 μm PDMS fiber, 7 min desorption time, pH 7, 10% NaCl, 90 min extraction time at 24 °C), the correlation coefficients (r²) of the calibration curves of target compounds ranged from 0.9993 to 0.9999. The limit of detection (LOD) and limit of quantification (LOQ) ranged from 0.2 to 9.6 ng L⁻¹ and 0.7 to 32.0 ng L⁻¹, respectively. The developed procedure was applied to the determinations of four UV filters and five PCMs in river water samples and internal standard was used for calibration to compensate the matrix effect. Good relative recoveries were obtained for spiked river water at low, medium and high levels. The proposed SPME method was compared with traditional SPE procedure and the results found in river water using both methods were in the same order of magnitude and both are quite agreeable.     

燕山海泡石的研究及其在C1化学中的应用(英文)

采用化学分析、ＸＲＤ、ＦＴＩＲ、ＤＴＡ、ＴＧＡ、ＳＥＭ、ＴＥＭ以及ＢＥＴ吸附等方法对燕山海泡石的物理化学性能进行了表征。选择了四个反应体系表征海泡石载体催化剂的催化性能,即二氧化碳加氢甲烷化、二氧化碳加氢合成低碳烯烃、甲烷化法挣化合成氨原料气和选择氧化反应。结果表明,海泡石载体催化剂的催化活性优于以氧化铝和二氧化硅为载体的传统催化剂的催化活性。     

Synthesis and property of a novel sulfonated poly(ether ether ketone) with high selectivity for direct methanol fuel cell applications

A novel membrane material based on random copolymer composed of poly(acrylonitrile-([3-(methacryloylamino)propyl]-dimethyl(3-sulfopropyl) ammonium hydroxide)) (PAN–MPDSAH) was synthesized by the water phase suspension polymerization. The zwitterionic PAN-based membranes were prepared through blending PAN and PAN–MPDSAH copolymer by a phase inversion method. The zwitterionic PAN-based membranes have higher hydrophilicity and wettability, and lower protein adsorption in comparison with the control PAN membrane. Ultrafiltration experiments revealed that membrane fouling, especially irreversible membrane fouling, for the zwitterionic PAN-based membranes is remarkably reduced due to the incorporation of zwitterionic PMPDSAH segments on the membrane surfaces. Moreover, the reversible membrane fouling during ultrafiltration process can be easily washed away by simple water cleaning. The zwitterionic PAN-based membranes can run for a long time and be reused without significant decrease of separation performance.     

限域单分子层冰-水两相平衡体系的分子动力学模拟

限域水因有极其丰富的结构物相变化而成为近年来水科学研究的一个热点.然而,不同相限域水之间的相平衡结构与性质却鲜有报道.论文提出一套分子动力学模拟技术,可实现纳米尺度限域条件下冰和水的不同结构相间形成的低维固-液界面（线）的平衡态模拟.应用此模拟技术,我们探索了0.65 nm限域尺寸、5000 bar限域压强条件下,单分子层厚度的冰-水（固-液）两相平衡,计算了该平衡体系一系列热力学量在界线附近的分布.平衡态的分子模拟结果直观地展示了粗糙型固-液界线的热毛细涨落、界线固-液结构转变的微观机制、以及缺陷在固-液相变区附近的形成与输运.各种热力学量分布函数呈现了二维限域冰-水共存界面（线）的特殊性质,如：相平衡区域的尺寸异于块体材料固-液界面,固-液界线处于切向压缩状态等.     

A New Analysis of Volterra-Fredholm Boundary Integral Equations of Second Kind

In this paper, we study the existence, uniqueness and regularity of the solutions to Volterra-Fredholm boundary integral equations of second kind in a kind of boundary function spaces.