短脉冲激光作用下丙酮液池沸腾现象的瞬态观测

本文对短脉冲激光作用下试件表面的温度变化和丙酮液体汽泡行为进行了瞬态观测,研 究了激光参数和细小金属颗粒等因素对丙酮液体沸腾行为的影响。结果表明：激光参数中,脉宽是 影响温度曲线和汽泡行为的主要因素,随着激光脉宽增大,大汽泡的长大时间和脱离直径减小;汽 泡长大速度与常规沸腾时的完全不同,没有出现等温生长阶段,在激光脉冲后很长时间内汽泡长大 速度快速增大;试件表面覆盖细小金属颗粒后,沸腾过程变得非常剧烈。     

Conformational changes of a polyelectrolyte in mixtures of water and acetone

Samples of a polyelectrolyte poly(methacryloylethyl trimethylammonium methylsulfate), PMETMMS, with molar masses M_w = 22−25 × 10⁶ were examined with viscosity, static light scattering, and conductivity measurements in a water–acetone solvent. Because acetone is a nonsolvent for this polymer the measurements were performed to determine the influence of the solvent composition, the polymer concentration, and the presence of added ions on the conformation of the polyelectrolyte in mixed solvents. The possible influence of a hydrodynamic field on the polymer conformation was also studied. The viscosity of the polymer solutions as a function of polymer concentration, as well as of the solvent composition, was studied using a broad range of shear rates. When the mass fraction of acetone in the solvent, γ, is below 0.5, the solutions show a usual polyelectrolyte behavior. When γ ≥ 0.80, the polymer adopts a compact conformation. This is observed as a decrease of the radius of gyration, R_g, second virial coefficient, A₂, the viscosity, and also as a change in the conductivity of the solution. The change in the polymer conformation may be induced also by dilution. When 0.60 ≤ γ < 0.80, a gradual decrease in the polymer concentration leads to a sudden decrease of the reduced viscosity, which indicates a decrease in the particle size. The values of M_w measured by static light scattering were constant in all experiments. © 1998 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 36: 1107–1114, 1998     

Synthesis,physical characterization,and acetone sorption kinetics in random copolymers of poly(ethylene terephthalate) and poly(ethylene 2,6-naphthalate)

Random copolymers of poly(ethylene terephthalate) (PET) and poly(ethylene 2,6-naphthalate) (PEN) were synthesized by melt condensation. In a series of thin, solvent cast films of varying PEN content, acetone diffusivity and solubility were determined at 35°C and an acetone pressure of 5.4 cm Hg. The kinetics of acetone sorption in the copolymer films are well described by a Fickian model. Both solubility and diffusivity decrease with increasing PEN content. The acetone diffusion coefficient decreases 93% from PET to PET/85PEN, a copolymer in which 85 weight percent of the dimethyl terephthalate in PET has been replace by dimethyl naphthalate 2,6-dicarboxylate. The acetone solubility coefficient in the amorphous regions of the polymer decreases by approximately a factor of two over the same composition range. The glass/rubber transition temperatures of these materials rise monotonically with increasing PEN content. Copolymers containing 20 to 80 wt % PEN are amorphous. Samples with <20% or >80% PEN contain measurable levels of crystallinity. Estimated fractional free volume in the amorphous regions of these samples is lower in the copolymers than in either of the homopolymers. Relative free volume as probed by positron annihilation lifetime spectroscopy (PALS) decreases systematically with increasing PEN content. Acetone diffusion coefficients correlate well with PALS results. Infrared spectroscopy suggests an increase in the fraction of ethylene glycol units in the trans conformation in the amorphous phase as the concentration of PEN in the copolymer increases. © 1998 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 36: 2981–3000, 1998     

基于电喷雾电离质谱(ESI-MS)的丙酮稳定同位素标记对N-糖链的相对定量分析方法的研究

建立了一种基于电喷雾电离质谱的丙酮稳定同位素标记对N-糖链进行相对定量的研究方法. 与传统的PNGase F酶水解N-糖链的方法不同,采用非特异性蛋白酶Pronase E对N-糖蛋白进行处理,使N-糖蛋白被酶解为带有一个氨基酸的糖氨酸（Glycan-Asn）,为N-糖链引入了一个氨基活性基团,然后用丙酮对氨基进行标记. 用d₀/d₆丙酮对Ribo B标准糖蛋白的Pronase E酶解产物进行标记,考察了4对d₀/d₆丙酮标记的Glycan-Asn（Man₅～Man₈-Asn）在电喷雾电离质谱中的线性、动态范围以及重现性. 结果表明,在10倍动态范围内,相对定量方法有良好的线性关系（R=0.9981）和重现性（CV<8.7%）. 并将建立的方法应用于不同含量的鸡卵清白蛋白中,进一步验证了该方法的可行性. 研究结果表明,该方法能准确分析样品中N-糖链的含量,对不同样品中N-糖链进行相对定量. 该方法成本低廉,后处理方法简单方便,适于微量样品通量化分析,对差异糖组的研究有一定的意义.     

MgO/NaY催化糠醛和丙酮合成航空燃料中间体的性能研究

采用"机械混合-焙烧"方法制备了负载型固体碱催化剂MgO/NaY,研究了糠醛与丙酮在水-乙醇体系中的羟醛缩合反应,考察了催化剂负载量、原料配比、反应温度、反应时间等因素对催化剂性能的影响。结果表明,20%MgO/NaY催化剂表现出最佳的催化性能,在85℃条件下反应8 h后,糠醛转化率达到99.6%,亚糠基丙酮(FA)和二亚糠基丙酮(F₂A)选择性分别达到42.2%和57.1%,缩合产物的总收率为98.6%。高温促进反应中间体向产物的转化,有利于提高产物的总选择性。改变糠醛/丙酮的摩尔比可调控两种缩合产物的选择性,较高的糠醛/丙酮摩尔比有利于提高F₂A的选择性,但会降低整体反应速率。重复性评价表明,催化剂具有较好的再生性能。     

叶绿素丙酮溶液中热致暗空间光孤子实验

设计了热致暗空间光孤子的实验光路和偶边界条件的实施方案，在叶绿素丙酮溶液中实现了热致暗空间光孤子实验，并采用分步傅里叶变换法进行了数值模拟，发现两者的结果一致。     

气相色谱—傅里叶变换红外光谱联用技术用于分析工业丙酮中的杂质

本文提出了一种气相色谱－傅里叶变换红外光谱联用技术分析工业丙酮杂质成份的方法，该方法采用ＦＦＡＰ毛细管柱，柱长２５ｍ，内径０．２５ｍｍ，膜厚０．３３μｍ，占总面积１．１６％的１２种杂能够被分离和鉴定。     

2-(E-2-苯乙烯基)喹啉的合成

以苯甲醛为原料在碱性条件下与丙酮缩合得苄叉丙酮（1），1与邻氨基苯甲醛发生Friedlaender缩合反应得到新的目标产物2－（E－2－苯乙烯基）喹啉(2),产率81％。     

The Photochemistry of Acetone: The Primary Decomposition of Acetone and Biacetyl Yields

In the photolysis of acetone at 265nm at 27°C the quantum yield of biacetyl has been determined to be 0.34 and the primary decomposition yield is evaluated to be about 0.68. The fraction of triplet acetone decomposed into methyl and acetyl radicals is estimated to be 0.14 at 313nm. The acetyl radicals undergo reaction to form biacetyl 50 times faster than decomposition to methyl radicals and carbon monoxide.