碱-酶水解结合分散式固相萃取提高大豆异黄酮活性总量测定的准确性

通过碱性甲醇溶液超声提取,结合杏仁来源β-葡萄糖苷酶水解及聚酰胺分散式固相萃取步骤,建立了超高效液相色谱测定大豆异黄酮活性总量的方法。样品中的丙二酰及乙酰类大豆异黄酮苷在碱性条件下水解成基本型苷,并在β-葡萄糖苷酶的作用下进一步脱去糖基转变为相应的苷元。样品中12种不同形式的大豆异黄酮转变为仅含3种大豆异黄酮苷元(大豆苷元、黄豆黄素、染料木素)后,以聚酰胺粉进行分散式固相萃取,C_(18)反相色谱柱(2.1 mm i.d.×50 mm,1.8μm)分离。结果显示,大豆苷元、黄豆黄素及染料木素在3 min内实现基线分离,3种异黄酮苷元的标准曲线相关系数(r^(2))均大于0.999,总异黄酮的回收率为94.3%~102%,相对标准偏差(RSD,n=6)小于5.0%,具有较高的准确度和精密度。该方法通过检测样品中的全部苷元来计算异黄酮总量,有助于降低异黄酮检测在分离度、准确度及检测成本上带来的挑战;考虑异黄酮在体内的转化吸收机制和生理效应,以苷元总量计能更科学地反映实际的异黄酮活性水平,避免因通过苷和苷元的简单加和而造成对异黄酮含量水平的高估。

Effect of intergranular β phase on the rupture plasticity of the low expansion Inconel 783 superalloy

High temperature rupture specimens with different rapture plasticity are investigated. The rupture fracture failure of Inconel 783 superalloy is researched by analyzing the fracture surface and microstructure of the rupture specimens. The intergranular β phase precipitated sufficiently with favorable morphology can efficiently strengthen grain boundaries that can achieve a full plastic deformation of grains. Additionally, the intergranular β phase can effectively restrain the occurrence and expansion of intergranular cracks during the rupture test. The intergranular β phase insufficiently precipitated can weaken the intergranular cohesion and lead to the occurrence and expansion of cracks; thus, the grains cannot be fully deformed before breaking. Therefore, the β phase precipitated in the grain boundaries can significantly increase the rupture plasticity of Inconel 783 superalloy.

Effect of Substrate Characteristics on Interdiffusion Coefficients of Ni and Al Atoms in β-NiAl Phase of Aluminide Coatings

Interdiffusion coefficients at 950℃ and 1050℃ are calculated by Wagner analysis method as a function of composition of β-NiAI phase. The β-NiAI phase is formed by pack cementation on surface of superalloy. Results of the calculation show that interdiffusion coefficients in β-NiAI phase strongly depend on the compositions and vary over several orders of magnitude. Compared with the interdiffusion coefficients in the stoichiometric β-NiAI phase, the interdiffusion coefficients in β-NiAI phase formed on superalloy is obviously small, probably due to the composition, complicated microstructure and precipitates. However, it could be seen clearly that the shapes of the diffusivity curves are very similar to each other. The similarity of the diffusion curves and the difference between interdiffusion coefficients imply that the compositions, microstructures and precipitates of superalloy have a distinctly adverse effect on the interdiffusion of Ni and Al atoms during aluminization, but do not change the essential characteristics of β-NiAI phase.

Influences of Alloying Elements W, Mo, Cr and Nb on Retained Beta Phase in 47Al Based near γ-TiAl Alloys

The influences of alloying elements W, Mo, Cr, and Nb on retained ft phase in 47AI based near 7-TiAI alloys have been studied. The results reveal that the amount of retained β phase is increased by the addition of Cr, Mo, W in rising rank, although the distribution of β phase in Cr-bearing alloys is different from that of Mo- or W-bearing alloys. For Nb-doped alloys, no retained ft was found even when 5 at. pct Nb was added. The as-cast microstructural features and the distribution of the b phase in the different alloy families were compared and interpreted in terms of the different segregation behaviour of these elements in Ti.

Effects of Stretching Ratio and Temperature on Phase Transition of Melt-spun Poly(Vinylidene Fluoride) Fibers

The effects of stretching ratio and stretching temperature on pbase transition of melt-spun poly （ vinylidene fluoride ） fibers were investigated and analyzed by using scanning electron microscopy, wide angle X- ray diffraction, differential scanning calorimetry and Fourier transfer infrared spectroscopy. The β phase exists in the as-spun fiber. The β phase content increases as the stretching ratio increases. When the stretching temperature is lower than 100 ℃ , enhancing temperature is good for the transition of phase a to ft. By contrast, when the stretching temperature is higher than 100 ℃ , enhancing temperature is unfavourable for the transition of phase a to β. Increasing the draw temperature increases the α-phase content.

Improvement of β-phase crystal formation in a BaTiO3-modified PVDF membrane

In this paper,low temperature plasma is used to modify the surface of barium titanate（BaTiO3）nanoparticles in order to enhance the interfacial compatibility between ferroelectric poly（vinylidene fluoride）（PVDF） and BaTiO3 nanoparticles.The results demonstrate that oxygenic groups are successfully attached to the BaTiO3 surface,and the quantity of the functional groups increases with the treatment voltage.Furthermore,the effect of modified BaTiO3 nanoparticles on the morphology and crystal structure of the PVDF/BaTiO3 membrane is investigated.The results reveal that the dispersion of BaTiO3 nanoparticles in the PVDF matrix was greatly improved due to the modification of the BaTiO3 nanoparticles by air plasma.It is worth noting that the formation of a β-phase in a PVDF/modified BaTiO3 membrane is observably promoted,which results from the strong interaction between PVDF chains and oxygenic groups fixed on the BaTiO3 surface and the better dispersion of BaTiO3 nanoparticles in the PVDF matrix.Besides,the PVDF/modified BaTiO3 membrane at the treatment voltage of 24 k V exhibits a lower water contact angle（≈68.4°） compared with the unmodified one（≈86.7°）.Meanwhile,the dielectric constant of PVDF/BaTiO3 nanocomposites increases with the increase of working voltage.

Preparation of nanometer δ- and β-bismuth trioxide by vacuum vapor-phase oxidation

A stable δ- and β-bismuth trioxide was prepared at room temperature by vacuum vapor-phase oxidation. The average crystal size of products was 14.6 nm (by XRD), the d(0.5) value was in the range from 62 nm to 69 nm, and geometric standard deviation(GSD) was from 1.42 to 1.64. The results show that δ-Bi2O3 is formed when quenching rates is rapid and β-Bi2O3 is formed when it is slow. The size of grains increases with rising reaction temperature, flow rate of carrier gas, residual pressure of system and longer growing time of grains.

X-ray diffraction study of effect of deposition conditions on α-β phase transition and stress evolution in sputter-deposited W coatings

Pure W and W-Cu-W trilayer coatings were deposited on an Fe substrate by d.c. magnetron sputtering. The α-β phase evolution, intragranular stress evolution in sputter-deposited W layer were investigated by x-ray diffraction. They are directly related to the film microstructure, density and adhesion. Therefore, control of the film stress and phase component transition is essential for its applications. The phase component transition from β-W to α-W and intragranular stress evolution from tensile to compressive strongly depend on the deposition parameters and can be induced by lowering Ar pressure and rising target power. The compressively stressed films with α-W phase have a dense microstructure and high adhesion to Fe substrate.

Nuclephilic ring opening of epoxides promoted by multi-site phase-transfer catalyst:An efficient and eco-friendly route to synthesis of β-hydroxythiocyanate

A highly effective and mild protocol for ring opening of epoxides with NH4SCN in the presence of catalytic amount of a multi- site phase-transfer catalyst, α,α＇,α＂-N-hexakis（triethylammoniummethylene chloride）-melamine, is developed. A variety of ^-hydroxy thiocyanates as important intermediates in agricultural and pharmaceutical chemistry were obtained in high yields with excellent regioselectivity and in short reaction times. 2009 Ali Reza Kiasat. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.

MULTIPLE MELTING BEHAVIOR OF β-CRYSTALLINE PHASE POLYPROPYLENE

Differential scanning calorimetry and X-ray diffraction experiments on β-nucleated polypropylene were made on the samples crystallized at different temperatures and processed by injection molding. The crystal perfection was shown to vary with crystallization temperature. The observed multiple peaks could be related to a ill-phase with defective inclination of the chains, a recrystallized or original β_2-phase of more perfect inclination, and the α-phase. Injection molded samples could be analyzed from the established DSC interpretation.

Solid Phase Synthesis of β-Carbolines

Synthesis of β-carbolines on solid phase using TCCA as the key reagent is developed.

Compression behavior and phase transition of β-Si_3N_4 under high pressure

The compressibility and pressure-induced phase transition of β-Si3N4 were investigated by using an angle dispersive x-ray diffraction technique in a diamond anvil cell at room temperature. Rietveld refinements of the x-ray powder diffraction data verified that the hexagonal structure（with space group P63/m, Z = 2 formulas per unit cell） β-Si3N4 remained stable under high pressure up to 37 GPa. Upon increasing pressure, β-Si3 N4 transformed to δ-Si3N4 at about 41 GPa. The initial β-Si3N4 was recovered as the pressure was released to ambient pressure, implying that the observed pressureinduced phase transformation was reversible. The pressure–volume data of β-Si3N4 was fitted by the third-order Birch–Murnaghan equation of state, which yielded a bulk modulus K0= 273（2） GPa with its pressure derivative K0= 4（fixed）and K0= 278（2） GPa with K 0= 5. Furthermore, the compressibility of the unit cell axes（a and c-axes） for the β-Si3N4 demonstrated an anisotropic property with increasing pressure.

Synthesis of （2E）－α，β－Unsaturated Amides Catalyzed by Micro Palladium Under Solid－Liquid Phase－Transfer Conditions

Ｓｙｎｔｈｅｓｉｓｏｆ（２Ｅ）－α，β－ＵｎｓａｔｕｒａｔｅｄＡｍｉｄｅｓＣａｔａｌｙｚｅｄｂｙＭｉｃｒｏＰａｌｌａｄｉｕｍＵｎｄｅｒＳｏｌｉｄ－ＬｉｑｕｉｄＰｈａｓｅ－ＴｒａｎｓｆｅｒＣｏｎｄｉｔｉｏｎｓＤＵＪｉｎ－ｘｉｎｇ（Ｄｅｐａｒｒｍｅｎｔｏ...

Characterization of the β Phase Decomposition in Ti-5Al-5Mo-5V-3Cr at Slow Heating Rates

The influence of slow heating rates: 2, 5, 10 and 30?C/min (0.033, 0.083, 0.166 and 0.50℃/s) on the β phase decomposition of Ti-5Al-5Mo-5V-3Cr (Ti-5553) during continuous heating were characterized by differential scanning calorimetry (DSC) analysis, light microscopy, scanning electron microscopy, X-ray diffraction and hardness testing. Starting microstructure was the β phase obtained by heating the Ti-5553 above the Tβ temperature and a water quench. Results show that heating rate has a significant impact on the precipitation mechanisms and on the β→α transformation in this range of heating rates. The main formation of α precipitates occurs between 500 and 600℃at all heating rates tested.A heating at 2℃/min produces very fine and homogeneously distributed α plate precipitates which have nucleated on the nanometer size ωiso precipitates. The ωiso precipitates between 350 and 400℃. At higher heating rates 10, 15 or 30℃/min, the amount of precipitation of ωiso is lower so an additional formation of nanometer size precipitates occurs between 450 and 500℃ It is supposed that both precipitates act as nucleation sites for α phase precipitation. The resultant microstructure consists in a fine intragranular distribution of α precipitates and a coarser precipitation of α at the grain boundaries. It is shown that the precipitation of ωiso phase retards or prevents the precipitation of nanometer size precipitates occurring between 450 and 500℃. This cannot be generalized to all the β-metastable titanium alloys since Ti-LCB does not exhibit the same heating rate dependence on DSC curves.

基于β-糊精氧化石墨烯管尖固相萃取/高效液相色谱检测生活饮用水中苯并[a]芘

以自制的β-糊精氧化石墨烯(β-CD@GO)装填入10mL移液器吸头作为固相萃取剂,结合高效液相色谱法对生活饮用水中苯并[a]芘进行检测,并对固相萃取条件进行了优化。苯并[a]芘在0.1~50μg/L范围内线性关系良好(r=0.9996),检出限为3ng/L(S/N=3)。在加标水平为0.5、5、40μg/L时,方法回收率为89.2%~92.5%,相对标准偏差为3.7%~5.2%。该方法操作简便快速、选择性好、灵敏度高、有机溶剂消耗少,可用于生活饮用水中苯并[a]芘快速检测分析。

Analysis of α, β, γ-hexachlorocyclohexanes in water by novel activated carbon fiber-solid phase microextraction coupled with gas chromatography—mass spectrometry

A fast and simple method for determination of α, β, γ-hexachlorocyclohexanes (HCHs) in water using activated carbon fiber-solid phase microextraction(ACF-SPME) were studied. Results showed the performance of adsorption and desorption of three HCHs on ACF were excellent. A wide linear range from 10 to 100 μg/L and detection limits of the ng/L level were obtained using ACF-SPME with GC-MS in selected ion monitoring(SIM) acquisition mode. The proposed method was also successfully applied for determination of three HCHs in tap water. Compared to commercial fibers, ACF showed some advantages such as better resistance to solvents, higher thermal stability, longer lifetime and lower cost. The data demonstrated that GC-MS with ACF-SPME is well suitable for the analysis of HCHs in water.

磺丁基-β-环糊精-山奈酚的制备工艺及理化性能

采用相溶解度法研究2-磺丁基-β-环糊精对山奈酚的增溶作用和包合常数;以包合率为考察指标,考察包合工艺及包合过程中的理化性质变化规律。结果表明,磺丁基-β-环糊精-山奈酚包合物的相溶解度曲线为AL型,以n(磺丁基-β-环糊精)∶n(山奈酚)=1∶1形成包合物;最佳包合条件为m(磺丁基-β-环糊精)∶m(山奈酚)=3,t=40℃,t=4 h;t=45℃、c(磺丁基-β-环糊精)=1×10^(-2) mol/L,磺丁基-β-环糊精对山奈酚的增溶效果达到39.45倍;增溶效果在一定范围内与温度正相关;包合过程的热力学参数ΔG、ΔH和ΔS分别为-25.902 kJ/mol(318 K)、41.815 kJ/mol和213.51 J/(mol·K),表明包合反应为吸热反应,升高温度有利于包合反应的进行,反应能够自发进行;磺丁基-β-环糊精对山奈酚是一种较好的增溶载体。

Relationship between CO_2 Sensor Voltage Response and Phase Equilibrium of Solid Electrolyte Na,K-β/β″-Al_2O_3

A type of CO2 sensor based on oxygen concentration cell was designed as following: Cell I: Pt | Au, O2, CO2| Na2CO3(Au)|NKBA(Au)|YSZ|O2, CO2|Pt or Cell lI: Pt|Au, O2, CO2|K2CO3(Au)|NKBA(Au)|YSZ|O2, CO2|Pt. (Na,K-β/β'-AI2O3 is named by NKBA). The sensor signal is consistent with the Nernstian slope within the region of phase equilibrium for Na, K-β/β'-AI2O3 material. The relationship between CO2 sensor voltage response and phase equilibrium of solid electrolyte Na, K-β/β-AI2O3 is discussed in this paper.

(α+β)Dual Phase CuZnAl Shape Memory Alloy

The effect of α phase on CuZnAl shape memo- ry alloy(SMA)has been systematically studied by electrical resistance method,quantitative measure- ment of micrography and transmission electron microscopy(TEM).It is found that,by controlling the amount of α phase in(α+β)-CuZnAl alloy, phase transformation temperatures can be adjusted precisely in a wide range,while the good shape memory effect of CuZnAl is kept.In a word, quenching from(α+β)dual phase region is a rea- sonable method of adjusting phase transformation temperatures for CuZnAl alloy.

Synergistic Effect in Mixed Capillary Gas Chromatographic Stationap Phases Containing Heptakis(2,3,6-tri-o-pentyl)-β-cyclodextrin and Dibenzo-18-crown-6

used－silical capillary columns containing heptakis（2、3、6－tri－o－pentyl）-β-cyclodextrinand dibenzo-18-crown-6 were prepared．By studying the selectivity of mixed stationary phases forsome solute pairs.as well as comparing with the heptakis（2．3、6-tri-O-pentyl）-β-cyclodextrin and thedibenzo-18-crown-6 used as individual stationary phase、the synergistic effects were observed.These effects were affected by the column temperature．mixed ratio and linear velocity of carrier gas．