浊度法测定照相明胶的抑制性能

<正> 一、前言照相明胶的抑制性能对乳剂制备的影响很大。在制备乳剂的条件基本相同的情况下,采用不同类型的明胶,可以得出很不相同的照相性能。众所周知,卤化银微晶体的颗粒的大小对乳剂的照相性能有很大的关系。浊度法是测定经一定时间成熟后的卤化银颗粒的分散情况。当悬浮在明胶溶液中的卤化银微晶进行物理成熟(加热)时,其颗粒的分散情况就发生变化:较小颗粒溶解,     

用高聚物改善明胶物性的研究动向

<正> 一、概述自从1871年明胶被应用到卤化银乳剂中,由于明胶具有下列不可比拟的特性:如作为卤化银颗粒的保护胶体,在酸碱介质中具有稳定的胶体性能,对温度的可逆凝胶化特性,明胶内抑制剂抑制物理成熟和化学成熟,降低灰雾,而明胶含的增感剂却使二成熟后的乳剂增感,影响乳剂性能,光解时明胶是卤素的受体,光解后对于潜影中心又是优良的保护载体等,因此,至今它仍是银盐感光材料最好的粘合剂。但是,明胶是一种天然的高分子化合物,其组份十分复杂,工艺重现性差,因而导致质量不易统一;同     

明胶大分子对卤化银乳剂照相过程的影响

<正> 自从1871年Maddox将卤化银晶体分散于明胶制作照相材料以来,到现在一百多年,明胶仍然是卤化银的分散介质和粘合剂的主要原料。明胶具有许多适合于制作照相材料的物理的和化学的性质;这些性质是其它天然的和合成的聚合物所没有的。目前只能用合成聚合物取代部分明胶,以改善照相材料的物理机械性能。明胶聚肽大分子由18种氨基酸组成。认为影响卤化银乳剂照相过程的主要是其中一些含氧、氮、硫的氨基酸残基,如表1所示。 1.明胶在卤化银晶体表面的吸附明胶大分子主要是通过它在卤化银晶体表面的不可逆吸附来影响照相过程的。通常,聚合物分子以其在溶液中的无规线团构象吸附于固体表面,并且大分子只将     

明胶大分子的照相性质研究进展

<正> 目录 1.导言 2.明胶对卤化银乳剂微晶体颗粒性质的影响 3.明胶大分子对卤化银乳剂微晶体晶体习性的影响 4.明胶大分子的还原性与蛋氨酸残基的化学形态 5.明胶大分子作为曝光时的卤素受体 6.明胶大分子的感光性能与还原性关系     

照相明胶物理抑制性的鉴定

<正> 一、前言照相明胶中的微量活性物质对卤化银晶体的生长会产生重要影响。尽管至今尚不能用化学方法鉴定明胶中的全部活性杂质,但借助浊度法间接测定这些活性物质对卤化银乳剂物理成熟的影响是较为成功的。目前,国内感光行业乳剂技术的进展,已促使国产照相明胶进入情胶时代。因此,检验照明胶的抑制性应作为鉴定照相明胶的一个重要参数。在照相明胶史上,用浊度法检验明胶的抑制性可追溯到半个多世纪前。Steigmann首先捐出明胶巾存在抑制剂,并研究和制定检测抑制剂的方法——浊度法。其后,不少科学工作者对此展开了大量研究工作。其     

明胶卤化银乳剂制备的物理化学基础

<正> 十、参考书一、引言明胶是现代照相乳剂重要成分之一。它对照相乳剂多方面的重要作用一直为人们所关注。明胶在乳剂制备过程中明显地影响着乳剂的最终性能。明胶在卤化银上的吸附使颗粒悬浮,特别是沉淀阶段可以防止聚集而不使颗粒沉淀析出;明胶大分子的特性影响着卤化银的结晶休成长速度;明胶中含有某些增感杂质有利于进行化学增感;明胶的还原性与乳剂的敏度密切相关;明胶可逆的     

直接负性胶片

波拉公司最近推出一种新型自显影负片。在胶片中,未曝光区域的卤化银还原成低遮盖力的银,而曝光过的卤化银被还原成高遮盖力的银。底片是由涂有防光晕层的透明片基、负性乳剂层和明胶或乙烯醇的光学保护层组成。扩展纸由涂有酸酐聚合物,如:乙烯酸酐或马来酸酐聚合物丁酯中性层的片基,明胶     

明胶接枝改性及应用

<正> 一、引言有关明胶的接枝改性,很多人是感兴趣的。明胶接枝以后,可以提高它的机械物理性能,具有较高的弹性,热稳定性及耐磨性,因此在感光材料及皮革工业中应用它,可以提高涂层的质量。明胶接枝物还可以作为卤化银的沉降剂,沉降卤化银微晶。本文采用明胶与甲基丙烯酸甲酯和甲基丙烯酸(或丙烯酸)混合单体的辐射接枝,研究明胶接枝物作为沉降剂使用的可能性。     

PA改性明胶在21度胶片乳剂中的应用研究

<正> 一、引言现代感光材料制造工业中,工艺技术上的两大成就是浓缩乳剂和多层一次挤压涂布。浓缩乳剂与挤压涂布相结合,提高了胶片的质量和产量,经济效益显著增加。制备浓缩乳剂的方法很多,如冷冻脱水、电渗析法等,但是现已得到广泛应用的是沉降法。众所周知,老式除盐方法是水洗法。明胶卤化银的药条在冷水中洗去多余的盐分。经过水洗的药条吸水膨张,使卤化银乳剂稀释,因此用水洗法难于制作浓缩乳剂。沉降法则是在乳化前或物理成熟后加入沉降剂,在物理成熟结束后,通过调节 pH 值使明胶     

干牛骨制彩色感光材料用照相明胶

<正> 自从1890年明胶用于卤化银乳剂以来 感光材料工业有了飞速发展,照相明胶一直是感光材料工业关键的原料之一。明胶独特的冷凝性质和成膜性能可以得到很好的涂布质量,它对卤素的接受性能和胶体的保护性能,有助于卤化银感光层稳     

电位法测定明胶的还原性

使用电位滴定法测定了30种不同类型的LAG明胶的还原性,并进行了比较。结果表明:不同工艺过程,不同原料所制造的明胶的还原性大不相同。即使是同属于一种类型的惰胶,它们的还原性仍表现出了很大的差别。由于工艺条件的不同,明胶中还原组份的组成和化学本性可以有较大的差别,从而导致明胶的还原性质也会大不相同。这在一定程度上能解释同一类型的惰胶在照相性能上的差别。     

富氧燃烧烟气净化工艺研究进展

随着工业的快速发展,化石燃料消耗与日俱增,造成了大量温室气体CO₂的排放,全球气候变化形势不容乐观。为了减少CO₂排放,需要对高浓度CO₂进行捕获、利用与封存,而富氧燃烧技术能有效实现碳捕集,是目前最具潜力的碳减排技术之一。富氧燃烧过程中,SO_x、NO_x、Hg等污染物以及惰性气体的存在不利于碳的捕集与封存。烟气中各成分浓度会对管道运输、地质储存和提高采收率(EOR)产生影响,介绍了烟气中CO₂及各种杂质浓度的不同标准,系统综述了国内外脱硫、脱硝、脱汞和惰性气体脱除以及联合脱除技术的研究进展。脱硫部分除介绍传统脱硫技术外,重点描述了富氧燃烧烟气中CO₂气氛对SO_x脱除的影响以及加压条件下SO₂的转化与去除。发现CO₂气氛下SO₂的吸收速率相比N2气氛有所降低,且SO₂吸收过程中临界pH发生变化。脱硝部分重点描述了氧化吸收法脱硝技术以及加压条件下NO的氧化机理,并对高压下NO的氧化动力学进行阐述。随着压力的增加,NO氧化速率常数呈先下降后上升的趋势,且证明了反应器压力对液体夹带率的影响比较显著。总结了Hg脱除技术中不同烟气成分对Hg氧化的影响,HCl与Cl2起到了明显的促进作用。对活性炭进行改性,增加孔结构比表面积以及吸附剂表面的活性位点,提高Hg的脱除效率。介绍了惰性气体的净化技术,主要采用变压吸附方法来吸附和解吸附,降低了CO₂气流中惰性气体去除的成本,实现一部分惰性气体再次循环回到锅炉中,提高CO₂的捕获。重点讨论了在烟气压缩液化系统中的联合脱除技术,有效利用压缩过程条件将SO_x、NO_x、Hg分别以硫酸、硝酸、Hg(NO₃)₂形式协同去除,随着压力的增加,SO_x与NO_x去除效率提高,有利于SO₄^-2、NO₃^-、HADS和HAMS(N-S化合物)的生成,同时也导致了N2O生成量增多。证明了Hg与NO₂是气相反应,提出了高压下NO₂与Hg反应产物的不确定性。简单介绍了低温碳捕集技术,有潜力取代洗涤器和其他烟气处理方法,但目前还缺乏可行性的研究。未来需对不同压力下NO氧化速率常数的变化趋势进行解释,高压下NO_x与SO_x联合脱除的产物以及NO₂与Hg的反应产物进行分析。     

Physical and mathematical models of an inert macroelectrode modified with active hemispherical microelectrodes

The physical model of an inert electrode partially activated with hemispherical microelectrodes was formed by the deposition of silver grains on a graphite substrate. It is shown that the process on the microelectrodes can be under activation control despite the fact that the overall rate is determined by the diffusion layer of the macroelectrode. On the basis of this conclusion a mathematical model of mass transfer on an inert electrode partially covered with active hemispherical particles (microelectrodes) is given and verified qualitatively by appropriate experiments. It was found that the degree of activation does not depend on the size of the particles, but on the ratio of the radius of the particles to the interparticle distance. This means that the quantity of catalyst required for the transformation of an inert electrode into an active one decreases strongly with decreasing active particle size. It was also shown that the maximum current density to the activated inert electrode was equal to the limiting diffusion one to the massive active electrode, as well as that the activity of the modified inert electrode at the same coverage of catalyst strongly depends on the exchange current density of the electrochemical process taking place on it. The larger is the exchange current density, the lower is the quantity of catalyst required for the same effect on the activity of the modified electrode.     

5-氟尿嘧啶/明胶纳米载药微球的制备及体外性能研究

目的：以5-氟尿嘧啶(5-FU)为模型药物,明胶为载体材料,制备5-氟尿嘧啶/明胶纳米载药微球,探究药物的缓释效果和抗肿瘤性能。方法：“单凝聚相法”制备明胶纳米载药微球;透射电镜（TEM）和粒径分析仪（DLS）分析纳米微球的形貌、粒径分布情况;计算其包封率和载药量,并对其体外缓释效果和抗肿瘤性能进行研究。结果：明胶纳米微球的表面形态良好,分散均一,平均粒径65.1?2.1 nm,明胶纳米微球的包封率为23.5?1.9 %,载药量为69.7?0.5 %;明胶微球具有良好的缓释性能,Higuchi方程对微球的体外药物释放情况拟合度较高。四甲基偶氮唑蓝实验结果表明,5-FU/明胶微球对胃癌细胞(SGC7901)具有明显的抑制作用。结论：5-FU/明胶微球缓释性好,抗肿瘤活性显著,可作为抗癌药物的缓释制剂。     

Dielectric analysis for in‐situ monitoring of gelatin renaturation and crosslinking

This article probes the use of dielectric analysis (DEA) to monitor the physical changes that occur during gelatin renaturation and crosslinking. An interdigitated dielectric sensor was used to monitor ionic mobility in gelatin. In spite of the large concentration of water and ions in the gelatin model systems, a range of frequencies was found where DEA met all the requirements for ion viscosity measurements necessary to monitor aging gelatin. DEA was successful at detecting gelatin renaturation with a remarkably high signal‐to‐noise ratio. DEA was also capable of detecting crosslinking in the presence of formaldehyde, but only in the special case of fish gelatin. Unlike acid bone gelatin, which is semicrystalline at room temperature, fish gelatin remains fluid. Thus, fish gelatin provides a model system where crosslinking can be monitored in the absence of interference by renaturation processes. The dielectric response was also found to be sensitive to water transport between acid bone gelatin and a simulated pharmaceutical fill made of a PEG 600‐water solution. In the case of acid bone gelatin, the kinetics of renaturation as detected from DEA closely matched those measured by monitoring the evolution of the melting point and of the enthalpy of melting as measured by differential scanning calorimetry (DSC). With dynamic mechanical analysis (DMA), the rise in the loss modulus with renaturation also closely tracked the increase in ionic viscosity. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2765–2775, 2006     

Easy detectable isocyanate in the reaction with gelatin

Gelatin reactivity with isocyanate was studied by using the easy detectable 1-naphthyl-isocyanate (NphI). Four different NphI/gelatin feed ratios were investigated with NphI molar amount ranging between 1/10 and 1/1 with respect to the possible reactive groups of gelatin. The reactions were carried out at 45 °C in DMSO as solvent, under nitrogen atmosphere. Modified gelatin samples were characterized by IR, UV–VIS, fluorescence spectroscopies as well as by proton and DOSY NMR. Spectroscopy results allow to evidence the presence of both bonded and unbonded naphthyl derivatives in the gelatin samples. Unbonded species were present particularly at the highest NphI/gelatin feed ratio and their formation was correlated to the increasing competition of the reaction with water since the amount of available reactive groups on gelatin was comparable or smaller than the amount of residuum water in dry gelatin.     

微量活性引发剂促进惰性引发剂引发环氧乙烷的开环聚合速率研究

研究了利用微量更活泼的阴离子引发剂促进具引发惰性的磺胺嘧啶钠引发环氧乙烷开环聚合的反应速度，作了系列比较，并讨论了其影响速率的机制。     

Characteristics and gel properties of gelatin from goat skin as affected by spray drying

Gelatin powder from goat skin prepared by spray drying at various inlet temperatures (160–200°C) was characterized. Predominant particle sizes were in the range of 4.65–5.14?µm. Gelatin powder was mostly concave in shape with varying sizes, depending on inlet temperatures used. All gelatin powders were creamy whitish. Powder generally became more yellowish as the inlet temperature of spray drying increased (p?p?p?p?>?0.05). Goat skin gelatin spray dried with inlet temperatures of 160 or 180°C had higher gel strength than commercial bovine gelatin (p?相似文献   

Mensch-Prozeß-Kommunikation

Man-process communication . Computers are extensively used to control technical processes, but man is still irreplacable as observer and decision maker. The paper gives an overview of the channels existing between man and process. These channels have to deliver as much information as necessary, but as little as possible to allow the right decisions. Good models, concerning the production process and its individual phases, the structure of the control system, and the behaviour of man are required to extract the relevant information out of a large amount of data. Methods of signal processing and pattern recognition help to reduce the dimensionality of the active state vector allowing the control system to provide ?information”? instead of a collection of ?signals”?. The paper also describes the state and future development of important technological aspects, e. g. interactive display systems and real time data base systems.     

新型耐酸耐碱胶黏剂的研制

设计了一种新型呋喃树脂。经过试验确定了新型树脂的合成工艺。并用该树脂与固化剂,惰性添料配制成胶黏剂,测试其常温、热处理及腐蚀后的胶的力学性能、腐蚀率及胶化时间。测试结果表明：该树脂胶具有良好的耐酸耐碱性能。通过性能比较,可以得出如下结论：自制的呋喃树脂胶已接近或超过了国内外呋喃系列树脂胶的性能。可以代替这些胶用于化工防腐施工上。试验证明采用新的配料操作步骤,避免了爆聚现象的发生,改善了施工性能。