Critical-point wetting at the metastable chemical binodal in undercooled Fe–Cu alloys

Complementary results of differential thermal analysis and microstructural examination on Fe–Cu alloys provide the first evidence for critical-point wetting occurring at a completely metastable miscibility gap. The perfect wetting conditions hold for a composition range of 50–65 at.% Fe in the vicinity of the critical concentration. For samples encased with a glass slag, the Cu-rich liquid completely wets the glass upon undercooling to the metastable miscibility gap. In the perfect-wetting range, the metastable homogeneous liquid phase exhibited phase separation without undercooling below the chemical binodal. At deep undercooling, solidification of alloys with phase separated liquids results in a coarse scaled two-phase microstructure. In contrast, the homogeneous liquid phase of samples with compositions outside the perfect wetting range did undercool below the equilibrium onset of the metastable phase separation reaction. The phase separation in these samples occurred on a much finer scale. For samples without a glass encasement and thus in the presence of the Al₂O₃ crucible and an iron oxide layer, perfect wetting occurred near the consolute point on both sides of the metastable miscibility gap. This demonstrates that critical-point wetting is independent of the surface environment, but the wetting phase selected is surface sensitive.     

工件定位误差的尺寸链解法分析

本文应用尺寸链原理,对工件在机床夹具中常见的定位方式的基准不重合误差和定位副制造不准确误差进行分析计算。该分析计算简便、直观、统一,易于掌握。     

Extracting bio-zinc and taurine from Pinctada martensii meat

Recently, intensive processing of marine resources has attracted considerable attention. In order to further utilize the byproducts of aquatic shellfish (Pinctada martensii meat) with high value, this study proposes a method of extracting zinc and taurine from P. martensii meat. Zinc was first extracted from P. martensii meat with an ultrasonic crusher, and then taurine was further extracted by ultrasonic-assisted water extraction from the remaining shellfish. After optimization, the biological zinc extraction rate reached 8.63%, and the taurine extraction rate reached 0.71%. Meanwhile, the parameters for cation exchange separation and taurine purification were optimized, in which the injection volume, pH value, and elution rate were set to 8.0 mL, 4.5, and 3.0 mL/min, respectively. Ultimately, the purity the extracted taurine reached 98.16%. This study provides a novel method for the extraction of biological zinc and taurine by deep processing of shellfish meat.     

高效液相色谱法测定肉桂醛生物转化体系中10种苯基香料

建立一种同时测定微生物转化肉桂醛体系中10种天然苯基香精香料(苯甲醇、苯甲醛、苯甲酸、苯乙醇、苯乙酮、肉桂醇、肉桂醛、肉桂酸、3-苯丙醇和3-苯丙醛)的高效液相色谱分析方法。试样经无水乙醇提取,离心,过滤后进样。色谱分析采用SunFireTMC18色谱柱(250 mm×4.6 mm,5μm),以甲醇∶乙腈∶水∶冰醋酸=28.4∶18∶53.6∶0.04(体积比)为流动相,流速1.0 mL/min,紫外检测器检测。10种待测物在2.00 mg/L^318.60 mg/L范围内线性关系良好(0.9987≤R2≤0.9996),方法检出限(method detection limit,LOD,S/N=3)为0.36 mg/L^1.16 mg/L,在低、中、高3个加标水平下的平均回收率为92.13%~102.90%,RSD为0.62%~4.01%。该方法可用于微生物转化肉桂醛合成天然苯基香料的生物反应体系的成分分析,也可用于生物转化肉桂醛合成天然香料的菌种选育工作中。     

Synthesis and complexing properties of resins containing aminocarboxylic acid as functional groups from diethylenetriaminepentaacetic acid bisanhydride and polyvinyl alcohols

The one-step reaction of diethylenetriaminepentaacetic acid bisanhydride with polyvinyl alcohols of different molecular weights produces chelating resins containing aminocarboxylic acids as functional groups. Metal sorption in different hydrochloric acid concentrations media and desorption studies were carried out and the results compared according to the density of complexing groups. The resins show a great sorption affinity towards Au(III). The desorption of Au(III) from the resins carried out by applying perchloric acid or thiourea as eluting agents led to the assumption that gold is strongly complexed indicating a particular mechanism of metal sorption.     

Cobaltacarboranes [closo-(9-R2N-1,7,9-C3B8H10)-commo-2,(3′)-Co-(1′,2′-C2B9H11)] (where R=H and Me) — crossover complexes between metallatricarbollides and metalladicarbollides

Reactions between 7-L-nido-7,8,9-C₃B₈H₁₀ compounds (where L=Bu^tNH₂ and Me₂NH) and [NMe₃H]⁺[7,8-C₂B₉H₁₂]⁻ in the presence of NaH, followed by the addition of anhydrous CoCl₂ and prolonged heating in diglyme at reflux, resulted in the isolation of mixed-ligand 12-vertex cobaltacarboranes [closo-(9-R₂N-1,7,9-C₃B₈H₁₀)-commo-2,(3′)-Co-(1′,2′-C₂B₉H₁₁)] (where R=H or Me). These represent neutral, crossover complexes between metallatricarbollides and metalladicarbollides and contain amino groups attached to p-positions with respect to the metal centre.     

Al-W二元系的机械合金化

用机械合金化方法由元素粉末制备了Ａｌ１ － ｘ Ｗｘ（ ｘ ＝ ０ ．１ ,０ ．２ ,０ ．５ ,０ ．９） 合金。用Ｘ 射线衍射法对球磨后的粉末进行了分析, 并用扫描电镜和透射电镜观察了形貌并研究了晶相结构。结果表明, 球磨后Ａｌ 在Ｗ 中的固溶度大大扩展, 但球磨到２５０ｈ 该系统仍未形成非晶; Ａｌ０ ．５ Ｗ０ ．５ 粉末经２５０ ｈ球磨后出现一结构为体心四方的新相。热力学计算表明该系统不能形成非晶     

马氏珠母贝综合利用的研究进展

马氏珠母贝是我国南方沿海地区人工养殖生产珍珠的主要贝类,目前已在养殖生态、插核育珠、营养成分和生物活性等方面对其进行了广泛的研究。文章综述马氏珠母贝所育珍珠、贝壳和贝肉营养成分、生物活性分析及其应用等方面的研究进展,为马氏珠母贝的进一步研究利用提供理论依据。     

Effects of pH on a fluorogenic vital dyes assay (4′,6′-diamidino-2-phenyl-indole and propidium iodide) for Cryptosporidium sp. oocysts

The fluorogenic vital dyes assay utilizing 4′,6′-diamidino-2-phenyl-indole (DAPI) and propidium iodide (PI) can be used for determining the viability of individual Cryptosporidium parvum oocysts isolated from environmental samples; however this assay can be affected by the pH of the oocyst suspending medium, resulting in formation of fluorescent yellow DAPI crystals at neutral or alkaline pH. Interference from DAPI crystals can lead to oocyst occlusion, making their viability assessment difficult or subjective. When the oocyst suspending medium is rinsed with HBSS adjusted to pH 4, DAPI crystallization is reduced or prevented without affecting oocyst staining characteristics with these two dyes or with fluorescein isothiocyanate conjugated anti-Cryptosporidium monoclonal antibody.     

Macroscopic synthesis of onion-like graphitic particles

In this paper, we present a method for macroscopic synthesis of onion-like graphitic particles, which may be used to study physical properties. This method is based on annealing carbon nanotubes under high pressure. By transmission electron microscopy (TEM), the microstructure of carbon nanotubes is found to transform into quasi-spherical graphitic structures when the sample has been treated at 770 °C and 950 °C under 5.5 GPa. The high pressure assumes an important role in this transformation.