Asymmetric dimers can be formed by dewetting half-shells of gold deposited on the surfaces of spherical oxide colloids

Asymmetric dimers consisting of gold microcrystals and spherical silica colloids have been fabricated by depositing thin films of gold onto the spherical colloids to form half-shells, followed by annealing at elevated temperatures. The capability and feasibility of this procedure have been demonstrated with silica and titania beads of 0.2-2 mum in diameter and gamma-Fe2O3/polystyrene@SiO2 core-shell particles 0.5 mum in size. The dimensions of gold microcrystals could be conveniently varied in the range of 100-650 nm by controlling the thickness of gold films and/or the diameter of the spherical colloids. This method provides another route to asymmetric dimers made of colloidal particles that could be different in size, chemical composition, surface functionality, density or sign of surface charge, bulk property, or a combination of these properties.     

不依赖于统计模型的手性毛细管电泳分离多指标同时优化

考虑到手性毛细管电泳分离机理的复杂性，提出了不依赖于统计模型的二进制编码遗传算法多目标优化策略。根据实验参数的多少及其重要性，采用均匀设计安排完成初步实验。并用Derringer功效函数作为多指标同时优化的评价指标，以取得较高的分离度和较快分离速度；通过对实验参数给予编码，转化为二进制字符串，根据得到的总功效函数值大小进行遗传算法操作，产生新的一组实验条件。重复上述过程直到得到最佳分离条件为止。此方法成功地应用于华法令对映体的毛细管电泳分离条件优化。     

Study on the oligomerization of cyclopentadiene and dicyclopentadiene to tricyclopentadiene through diels-alder reaction

Summary The oligomerization of cyclopentadiene (CPD) and its dimer, dicyclopentadiene (DCPD), to tricyclopentadiene (TCPD) through Diels-Alder reaction at temperatures between 120 and 150°C was investigated. The results show that reaction temperature, pressure and solvent influence the product yield; at 150°C up to 50% yield of TCPD was obtained in the absence of solvents. The ratios of isomers A to B in the product can be adjusted by using different solvents. The kinetics indicate that the rate is more sensitive to the concentration of CPD than to that of DCPD.     

开链冠醚Schiff碱-稀土配合物的合成、表征及近红外发光光谱研究

合成了3个新型开链冠醚Schiff碱-稀土离子三元配合物RE(H2L)(Mq)(NO3)3,其中RE=Nd3 ,Er3 ,Yb3 ,配体H2L=N,N-双(邻羟苯亚甲基)-3,6-二氧杂-1,8-二氨基辛烷,Mq为8-羟基喹哪啶.采用元素分析、红外光谱(IR)、紫外-可见吸收光谱(UV-vis)、热重-差热分析(TG-DTG)等手段对配合物的组成结构进行了表征.测定了3种新型结构稀土三元配合物在不同温度(77 K和300 K)时的近红外发光光谱.     

生物质裂解产物的制备及HPLC检测其成分的虚拟仿真实验开发

In order to improve university laboratory teaching and practical education under the background of information technology, as well as overcome the difficulty for practical training, develop a virtual simulation experiment platform for rapid pyrolysis of natal materials and high-performance liquid chromatographic (HPLC) detection of its components. The experiment integrates the actual operation process of the plant to produce cleaved products by rapid pyrolysis of biomass with HPLC detection. The virtual experiment is divided into biomass sample pretreatment, rapid biomass pyrolysis, bio-oil extraction, and HPLC determination of complex components, making the biomass cleavage workshop "real" through simulation. This virtual simulation experiment fully integrates the utilization of biomass resources and basic chemistry courses (such as organic chemistry, instrumental analysis, chemical engineering principles, etc.), which are widely involved in agricultural and forestry majors with advantageous characteristics value.     

High-resolution Hadamard transform microscope fluorescence imaging: quantifying the DNA content in single cells

This study presents a novel miniaturized Hadamard transform fluorescence imaging microscope, by combining a conventional fluorescence microscope with Hadamard transform multiplexing encoding using a one-dimensional movable mask to realize spatial resolution and a linear CCD for multichannel detection. The microscope can provide high-resolution automatically-generated 0–255 gray level HT images for morphological analysis and visualization of a single cell, and normalized HT images for cellular quantitative measurements. The microscopes imaging capability was applied to measure the DNA content in human lymphocyte, chicken erythrocyte and eel erythrocyte, and a comparative study was performed. The results show that the calibrated DNA content in a chicken erythrocyte is 2.32 pg when human lymphocyte is used as the standard, and eel erythrocyte may be a potentially reliable and novel standard for determining DNA contents in other species because it has a stable DNA value of 2.06 pg, with a CV of 4.3% when 20 eel erythrocytes are measured. The results also demonstrate that the HT imaging microscope should be valuable in the fields of medicine and cell biology.     

Water／Oil Biphasic Hydroformylation of Higher Olefins over a TPPTS-Rh／SiO2 Catalyst

A novel TPPTS-Rh/SiO2 catalyst, prepared by directly modifying a heterogeneous high-surface-area Rh/SiO2 catalyst with water-soluble TPPTS ligands, could decrease the resistance of masstransfer in water/oil biphasic media for the hydroformylation of higher olefins. The catalytic performancefor hydroformylation on this biphasic TPPTS-Rh/SiO2 catalyst system was higher than those of thetraditional biphasic HRhCO(TPPTS)3 systems, owing to the chemical bonds between the highly dispersedRh metal particles and the TPPTS ligands. The catalyst system is applicable for hydroformylation ofhigher olefins such as 1-dodecene.     

以万古霉素为流动相添加剂的高效液相色谱法手性分析系统的建立

以丹酰化苯甘氨酸、丹酰化苯丙氨酸、丹酰化丝氨酸、丹酯化丙氨酸为模型化合物，通过对色谱柱类型、缓冲液类型、pH和盐浓度、万古霉素用量、甲醇用量、柱温等色谱参数进行考察，建立了以万古霉素为手性流动相添加剂在普通色谱柱上进行手性分析的色谱系统，并在该系统中成功地拆分了酮洛芬对映体。     

Study of a mathematical model of metal ion complexes in solvent sublation

Separation of metal ion complex, [(C(12)H(8)N(2))(3)Fe(2+)], with surfactant sodium dodecylphrate (DLS) complex from aqueous phase was carried out by solvent sublation, which obeys first-order kinetics. On the base of the complete transport mechanisms, the Langmuir adsorption, and the ion complex equilibrium in the aqueous phase, a mathematical model for the [(C(12)H(8)N(2))(3)Fe(2+)]-surfactant ion complex is obtained with the aid of the Mathematic 4.0 program, 4th Runge-Kutta method, and the Matlab programs. The effects of many parameters, such as K(a), K(l), K(ow), d(i), V(o), V(w), and Q(a), on solvent sublation are investigated. Furthermore, the simulation showed that the model is substantiated for experiments on the solvent sublation of the complex.     

Room-temperature ferroelectric and ferroelastic orders coexisting in a new tetrafluoroborate-based perovskite

The coexistence of multiferroic orders has attracted increasing attention for its potential applications in multiple-state memory, switches, and computing, but it is still challenging to design single-phase crystalline materials hosting multiferroic orders at above room temperature. By utilizing versatile ABX₃-type perovskites as a structural model, we judiciously introduced a polar organic cation with easily changeable conformations into a tetrafluoroborate-based perovskite system, and successfully obtained an unprecedented molecular perovskite, (homopiperazine-1,4-diium)[K(BF₄)₃], hosting both ferroelectricity and ferroelasticity at above room temperature. By using the combined techniques of variable-temperature single-crystal X-ray structural analyses, differential scanning calorimetry, and dielectric, second harmonic generation, and piezoresponse force microscopy measurements, we demonstrated the domain structures for ferroelectric and ferroelastic orders, and furthermore disclosed how the delicate interplay between stepwise changed dynamics of organic cations and cooperative deformation of the inorganic framework induces ferroelectric and ferroelastic phase transitions at 311 K and 455 K, respectively. This instance, together with the underlying mechanism of ferroic transitions, provides important clues for designing advanced multiferroic materials based on organic–inorganic hybrid crystals.

An unprecedented tetrafluoroborate-based perovskite reveals the coexistence of ferroelastic and ferroelectric transitions arising from delicate interplay between stepwise frozen organic cations and cooperative deformation of the framework.