脐橙保鲜方法与技术的研究

本文介绍了脐橙保鲜的意义,并简述了国内外有关脐橙保鲜技术与方法的研究进展和发展趋势。     

生物保鲜技术在果蔬贮藏保鲜中的应用

果蔬贮藏保鲜的发展,具有显著的经济效益和社会效益。生物技术在果蔬贮藏保鲜上的应用是近年新发展起来的具有发展前途的贮藏保鲜方法。本文概述了果蔬贮藏保鲜的原理和技术,同时对生物保鲜技术在果蔬贮藏保鲜中的应用进行了探讨。     

红阳猕猴桃采后贮藏保鲜技术研究进展

从果实的低温伤害、腐烂方面阐述红阳猕猴桃在贮藏过程中存在的问题,通过分析冷害的特点以及腐烂的因素,了解红阳猕猴桃贮藏中的问题,并从物理保鲜技术、化学保鲜技术及生物保鲜技术三方面综述红阳猕猴桃贮藏保鲜技术,通过阐述来掌握各保鲜技术的研究状况,展望了以后对红阳猕猴桃保鲜技术的深入研究趋势,为减少腐烂率,延长果实贮藏期提供理论参考和技术支撑。     

葡萄贮藏保鲜技术研究简介

韶关市工业科学研究所于1984年进行了葡萄贮藏保鲜技术的研究。经过两年多的研究试验,现已取得了较大进展,该所研制出对葡萄贮藏保鲜有明显效果的防脱果剂和SM—CY保鲜剂,探索了一整套对葡萄贮藏保鲜行之有效的技术方法。现将有关结论简介如下:     

果蔬气调贮藏技术

果蔬气调贮藏技术安亚平（中国化工信息中心，北京１０００２９）近年来，世界各国极为重视果蔬贮藏技术的研究开发，各种新颖的现代果蔬保鲜技术应运而生。其中，气调贮藏（ＣｏｎｔｒｏｌｌｅｄＡｔｉｎｏｓｐｈｅｒｅ）被认为是当今最经济最理想的果蔬保鲜技术。１气调...     

中华猕猴桃的保鲜贮藏研究

猕猴桃原产于我国,果实以营养丰富,风味佳美,皮薄汁多,功效特异被誉为果中珍品。但称为“水果之王”的猕猴桃具有生理后熟期,保鲜贮藏十分困难。人们称它“七天软,十天烂,半月以后坏一半”。因此,研究猕猴佻的保鲜贮藏技术,可使猕猴桃的资源优势变为商品优势,使其产生显著的社会经济效益。一、影响猕猴桃贮藏保鲜的因素影响猕猴桃贮藏保鲜的因素包括:品种及其适时采收,贮藏的温、湿度,乙烯含量,环境     

新型二溴二甲海因复合保鲜剂的研制

以二溴二甲海因为杀菌剂、以硬脂酸单甘酯及吐温 80为涂膜剂研制了一种新型水果和蔬菜复合保鲜剂 ,它具有高效低毒的特点。实验证实最佳保鲜条件为 :5 0kg脐橙使用w (二溴二甲海因 ) =0 0 5 %、w (硬脂酸单甘酯 ) =1 0 %和w (吐温 80 ) =2 .0 %～ 4.0 %的水基乳液进行保鲜处理后 ,贮藏三个月腐烂率仅 11% ,四个月后也只有 2 0 %的腐烂率。     

国内简讯

板栗保鲜贮藏技术研究通过了国家林业局组织的鉴定国家林业局重点科研项目“板栗保鲜贮藏技术研究” ,经西北农林科技大学科研人员4年多的努力 ,3月 1 4日通过了国家林业局组织的鉴定。专家认为 ,该技术达到国内领先水平。板栗是我国的主要经济树种之一 ,有“铁杆庄稼 ,木本粮食”之称。板栗果实营养丰富 ,含有多种矿质元素 ,经济价值较高 ,在国际市场受到青睐。但是由于板栗成熟季节比较集中 ,加之保鲜贮藏技术跟不上 ,致使每年有 1 5%～ 2 0 %的板栗发生失水、霉变。针对这种状况 ,西北农林科技大学科研人员从1 997年开始 ,通过对板栗采后…     

柑桔贮藏保鲜试验研究结果

本文介绍了以药剂处理为主的一套柑桔贮藏保鲜技术，在采收时用咪鲜安，异菌脲，２，４－滴的混合药液浸果，配合塑料袋单果包装及通风保温保湿措施，可有效地降低烂果率减少内含物质的变化，提高柑桔保鲜贮藏质量。     

光催化综合保鲜技术研究

果蔬在贮藏期间,由于乙烯的催熟作用、呼吸酶的氧化作用,导致其品质下降,贮藏期缩短。本文通过在油桃的保鲜过程中,对油桃散发出的乙烯进行光催化氧化降解处理,光催化和负离子综合作用抑制油桃果肉的褐变,研究该技术在冷藏条件下对油桃的保鲜效果。结果表明,光催化技术和负离子技术相结合,可以抑制油桃的腐败,有效延长油桃的贮藏时间。     

COMPARISON OF METHODS OF ANALYSIS OF GYPSUM1

The different analytical methods proposed for the evaluation of gypsum have been subjected to an experimental test. A combination method, consisting of a fusion with KHCO₃ and determination of CaO by KMnO₄ titration, the SO₃ by Andrews method of titration of BaCrO₄ has been found to give very reliable results with the least consumption of time.     

SEDIMENTATION OF BINARY MIXTURES OF PARTICLES OF UNEQUAL DENSITIES AND OF DIFFERENT SIZES

A model is developed for the sedimentation from a suspension of two particle species of unequal densities and of different sizes. The composition and the thickness of various layers in the sediments are predicted using graphical and analytical methods. The model predictions were in excellent agreement with experimental results, when the particle size ratio was ≥ 108. When size ratio of the particles was 2.60 and 4.31 the agreement occurred in about 50 percent of the cases.     

HEASUREHENT OF INSTANTANEOUS RATES OF LOSS OF VOIATILE COMPOUNDS DURING DRYING OF DROPS

A novel technique serves to monitor instantaneous rates of loss of a volatile solute from a suspended drop during drying. A highly sensitive electron capture detector is used to monitor concentrations of SF6 released into a flowing gas stream from a suspended, drying drop. Simultaneously, the appearance and morphological development of the drop are monitored with a video camera. This provides the wherewithal of relating instantaneous rates of loss of the volatile solute to particular events during the development of particle morphology.

Initial experiments have been carried out with drops of aqueous solutions of glucose, sucrose, maltodextrin and coffee extract. The results clearly display the onset of the volatiles-retentive selective diffusion phenomenon. There is also substantial loss of the volatile component later in the drying process, when the drops undergo repeated ex ansion, bursting and cratering due to the formation of internaf bubbles. These experiments appear to be the first quantitative demonstration of major losses accompanying changes in drop morphology.     

骑式摩托车油箱喷涂工艺的改进

面对日益激烈的市场竞争,摩托车油箱外观质量越来越成为影响销售的因素之一。文章介绍了改进工艺后的油箱涂装,该涂装体系提高了油箱外观的丰满度,降低了油箱涂装的生产成本。     

ANALYSIS OF RECENT MEASUREMENTS OF THE VISCOSITY OF GLASSES

Viscosity of Simple Soda-Silicate 500° to 1400°C Comparison of the results given by English with those of Washburn, Shelton and Libman, indicates a discrepancy in the absolute values of log₁₀ viscosity amounting to 0.6, those of Washburn et al., being relatively too high. If correction for this is made, the isothermal curves of log₁₀ viscosity as a function of soda content are smooth up to 50% Na₂O, showing no inflection. The observations as a function of temperature T are all represented within accidental error by an equation of the type where all three constants vary regularly with the composition. Change of Viscosity of Glass (6SiO₂, 2Na₂O) due to Molecular Substitution of CaO, MgO and Al₂O₃ for Na₂O The effect is clearly brought out by plotting (from the results of English) the change of log₁₀η due to the substitution as a function of temperature. The curves each show a sharp bend at a temperature between 840° and 1050°C, which is designated the aggregation temperature T_a. If we divide these curves by the corresponding percentage substituted, we get curves for each oxide which are straight and parallel below the aggregation temperatures, the slopes (increase of change of log₁₀η per 100°C) being −0.056 (CaO), −0.055 (MgO), −0.018 (A1₂O₃) per per cent oxide substituted. For substitution of 1/2 molecule the slopes are −0.325 (CaO), −0.23 (MgO) and −0.18 (Al₂O₃) per 100°. At the aggregation temperature the change of log₁₀η per per cent is a minimum, 0.03 to 0.06 for CaO, 0.12 for MgO, 0.07 for Al₂O₃. Evidence of Aggregation in Glasses, from viscosity Measurements The sharp bends in the plots of change of log₁₀η due to substitution of an oxide for Na₂O, suggest the beginning of molecular aggregation at these temperatures. These aggregation temperatures are close to the devitrification temperatures, but the effect on the viscosity curves cannot be due to actual devitrification since it does not change with time. Taking the aggregation temperatures as equal to devitrification temperatures, additional isotherms are roughly sketched into the equilibrium triangle of the system Na₂O-CaO-SiO₂. Change of Viscosity of Glass (4SiO₂, 2Na₂O) due to of Substitution of B₂O₃ for SiO₂ The change of log₁₀η (from the results of English) is plotted as a function of temperature, and also the change of log₁₀η per per cent B₂O₃. The curves are more complex than for the substitution for Na₂O.     

茶多酚提取方法进展

本文综述了国内外现有茶多酚提取方法的现状以及近期的研究进展，并对其优缺点进行了评价。这将有助于中低档茶的综合利用和茶多酚的进一步开发应用。     

己内酰胺水解聚合过程模拟──双官能团酸调节剂与尼龙6组成分布

提出了有双官能团酸相对分子质量调节剂存在时己内酰胺水解聚合过程动力学模型 ,并进行了实验验证 .对不同温度下聚合产物组成和各影响因素对数均聚合度的影响进行了模拟 .结果表明 ,数均聚合度随进料中水、氨基己酸及相对分子质量调节剂浓度的增加而减小 ,其中水的浓度影响较显著 ,且在考察浓度范围内相对分子质量调节剂浓度 [R]0 ≤ 0 0 0 68mol·kg- 1 时数均聚合度基本不变 ,而 [R]0 >0 0 0 68mol·kg- 1 时数均聚合度则显著减小 .无氨基己酸及相对分子质量调节剂时数均聚合度亦随水浓度增加而减小 .     

环氧树脂羟基值测定方法的研究

利用乙酸酐、吡啶和浓硫酸混合的乙酰化试剂测定环氧树脂中羟基值含量的方法具有操作简便、滴定终点明显和分析结果误差小等优点。     

气化工艺特性对IGCC效率的影响

影响煤气化联合循环总效率的五个主要因素为煤转化率、燃气轮机循环,蒸汽循环,热旁路比率和发电效率。其中以煤转化率影响最大,它将包括产品气的显热和剩余蒸汽。在任何气化装置中气化炉是最主要单元并极大地影响气化性能。为改善气化效率,所有第二代气化方法均已引入加压操作。本文讨论了高温操作、生严能力放大、负荷跟踪能力、加煤方式、气化剂和煤气净化,同时提出仍待开发的某些值得注意的问题。     

HYDRODYNAMIC CHARACTERISTICS OF THE PROCESS OF DEPRESSURIZATION OF SATURATED WATER

Experiments were carried out to find the effects of dissolved gas pressure,liquid flow rateand nozzle geometry on the bubble generation when saturated water was depressurized through anozzle.A new method,high speed camera system was developed to measure the generated microbubblesdynamically.On the basis of the laws of ideal gas and solution,theoretical generated gas flow ratewas deduced,while the Smoluchowski′s equation was applied to describe the kinetics of bubblenucleation.It was found that the size distribution of nucleated bubbles was of skewed distribution.An explanation to this phenomenon was made and the Gamma function distribution was employedfor mathematical simulation.The results show good agreement between the experimental data and thepredictions by proposed model.