银盐CTP版材物理显影过程及银堆积形态的研究

银盐扩散型CTP(Computer-To-Plate)版材基于银盐扩散转移原理.本文利用高分辨率的场效应扫描电子显微镜及CCD等手段研究了几种因素对该类版材物理显影银堆积状态及物理显影过程的影响.清晰地观察到不同曝光区物理显影银的堆积状态,在弱曝光区,银颗粒堆积紧密,是版材具有亲油性的主要原因.使用不同类型络合剂分别得到了颗粒状、树枝状等各种形态的物理显影银,表明络合剂对银颗粒形态有显著影响.通过CCD装置对版材上物理显影过程的实时原位监测,从动力学的角度解释了络合剂、显影温度对物理显影银堆积状态的影响.     

显影邻界效应的研究

本文研究了显影邻界效应。为了便于比较,无论在黑白显影或彩色显影中都使用了对苯二胺型显影剂。在黑白显影中,大面积密度差(H)和浓边密度增量(δ)之间存在着线性关系: δ=αH+b 直线的斜率α可以用作邻界效应强弱的度量。本文研究了显影剂活性、浓度、显影时间和显影液的pH对邻界效应的影响。在彩色显影中银影像和染料影像的邻界效应的关系呈显出复杂的情况。     

络合剂作用下光催化氧化纳米铁氧化物的生成及机理

进行了空气氧化Fe(OH)₂悬浮液, 络合剂(乙二胺、草酸、柠檬酸)作用下光催化氧化制备FeOOH的研究. 结果表明: 在室光下, 一定量乙二胺、草酸、柠檬酸的加入有利于纯γ-FeOOH的生成; 且随光强的增强, γ-FeOOH的晶化性降低. 机理分析表明: 可见光存在下, 络合剂的加入, 不仅使中间物绿锈GR(II)结晶度变差, 溶解加快; 而且络合剂与Fe^2＋形成的配合物可吸收部分可见光, 生成强氧化型的自由基, 使反应初期Fe^2＋快速氧化为Fe^3＋, 快的氧化速度利于生成低晶化度的γ-FeOOH.     

长链氨羧络合剂萃取稀土饵

研究了长链氨羧络合剂N,N′-二(十二烷基)乙二胺二乙酸钠(Na2R2Y)的氯仿溶液萃取稀土饵的行为;考察了溶液酸度、络合剂浓度、相比和温度对萃取率的影响.用摩尔比法测定了Na2R2Y与Er3+的络合摩尔比为1∶1;结果表明,Na2R2Y的氯仿溶液对饵的萃取率随络合剂浓度的增大而增大,随温度的升高而降低.     

显影抑制剂对银盐CTP版材的提高反差作用

高反差是印刷用感光材料的重要特性.本文着重研究了4种化学显影抑制剂对银盐扩散转移型CTP版材反差的影响.结果发现,硫代水杨酸、2-巯基苯并噻唑、6-硝基苯并咪唑和苯并三氮唑等单独使用时,对版材反差都有不同程度的提高作用;而硫代水杨酸与6-硝基苯并咪唑配合使用时,得到了超高反差效果.通过计算,给出了各个抑制剂最佳浓度时的反差系数值.另外,利用线性CCD技术对物理显影过程的研究表明,添加抑制剂扩大了不同曝光级的显影诱导期和显影速率之间的差别,从而提高了反差.     

用电化学方法研究显影过程——pH对菲尼酮-对苯二酚体系中亚硫酸盐添加效应的影响

应用旋转环盘电极(RRDE)等电化学方法研究了在不同pH条件下,在银/溴化银电极上,亚硫酸盐(SO₃^2-)对菲尼酮-对苯二酚超加合体系(P-H₂Q体系)显影反应速率的影响.结果表明,显影液中的亚硫酸盐不仅起保护显影剂的作用,而且影响显影反应速率.在较低pH下亚硫酸盐起抑制显影的作用,而在较高的pH下,会促进显影反应.这种现象可以认为主要是由于亚硫酸盐存在时,不同pH条件下,对苯二酚的氧化还原性质不同而引起的.     

二氧化碳基聚碳酸环己撑酯电子束光刻胶显影工艺优化

电子束光刻是下一代光刻技术中的有力竞争者,在微纳加工尤其是光刻掩膜制造上具有显著的竞争优势。 开发高性能的光刻胶并优化出最佳的显影条件和工艺是提升电子束光刻效率的基础。 本文在前期开发出的二氧化碳基聚碳酸酯电子束光刻胶的基础上,进一步探究了正性聚碳酸环己撑酯(PCHC)胶的显影条件对电子束光刻性能的影响,具体研究了显影剂以及显影温度和时间等工艺条件,筛选出了最优显影剂正己烷,最佳显影温度0 ℃,最佳显影时间30 s。 在该条件下,PCHC的灵敏度和对比度分别为208 μC/cm²和3.06,并实现了53 nm的分辨率,超过了当下广泛使用的PMMA-950k电子束光刻胶,有望为科研院所和半导体加工车间提供一种性能优异、成本低廉的新型电子束光刻胶。     

三苯基磷对PTG材料照相性能的影响

本文研究了三苯基磷(PPh₃)对以AgSt为银源的亲水型PTG材料照相性能的影响:PTG材料的感光度随PPh₃用量不同而变化,PPh₃用量相对较少时,感光度随PPh₃用量增加而提高;PPh₃用量增加到一定程度,感光度达到极大值;进一步增加PPh₃用量,感光度反而随PPh₃用量增加而下降.据分析结果推测,在PPh₃用量较少时,PPh₃的作用主要是打开AgSt二聚体的八元环而生成一种中间配合物,该中间体对热显影有促进作用;在PPh₃用量较多时,PPh₃的作用主要是与AgSt作用生成稳定的四元环配合物,该配合物对热显影有抑制作用.PPh₃的引入也会影响光敏元中潜影的形成效率,有利于提高感光度.     

光敏BZ振荡封闭体系振荡频率关系的研究

溴离子是振荡反应的抑制剂，其浓度减小的速率决定了振荡周期中自催化诱导期持续的时间，而振荡周期的总时长则取决于自催化诱导期，因此，溴离子能够影响体系振荡周期。而体系初始存在溴离子时，体系振荡频率与光强的动力学关系尚未研究。因此，在这项工作中，建立了Ru(bpy)₃²⁺催化Belousov-Zhabotinsky(BZ)均相封闭体系，研究溴离子存在时，体系振荡频率与光强的动力学关系，探究BZ反应物浓度对体系振荡频率曲线的影响。研究发现，初始存在溴离子时，体系振荡频率与光强之间仍然存在非单调关系。反应溶液中初始溴化钠浓度对于各反应物调制“振荡频率-光强”的效应起到不同作用：随着NaBrO₃浓度和MA浓度增高，体系振荡频率整体上向高频区域移动；随着HNO₃浓度的增加，体系振荡频率先向低频区域移动再向高频区域移动；随着NaBr浓度的增加，体系振荡频率向低频区域移动。这一研究为非线性系统的基础研究提供理论参考。     

酞嗪在苯并三氮唑银光敏热显影体系中的作用研究

本文对调色剂酞嗪(PHZ)在苯并三氮唑银(AgBTA)光敏热显影体系中的作用进行了研究,结果表明:PHZ加入AgBTA体系中可以起到促进显影的作用,并且该作用随着其用量的增加而增大;AgBTA体系中协同使用PHZ与邻苯二甲酸(H₂PA)的显影促进作用要好于单独使用PHZ的作用;在使用PHZ/H₂PA的AgBTA体系中,PHZ的促进作用与AgBTA乳液体系的pH值相关,在较低pH时,几乎没有促进作用,在较高pH值时,PHZ的促进作用较明显;电镜分析表明,PHZ与AgBTA生成银复合物而发挥显影促进作用.     

Facilitated transport mechanism in fixed site carrier membranes

Facilitated transport of gases, such as O₂, has been observed for fixed site carrier membranes. Carrier-impregnated ion-exchange membranes have also been used to produce facilitated transport of CO₂, H₂S and olefins when the carriers are not completely mobile. The actual mechanism for this facilitated transport has not been determined previously. The facilitated transport is provided by the exchange of solute between the free solute region and the bound complexing agent combined with gradients in the free solute and complexed carrier. The ratio of mobility for exchange between the regions is the dimensionless equilibrium constant of the reversible reaction. An expression is also derived for the relationship between the effective diffusion coefficient of the complex in facilitated transport, D_AB, and the diffusion coefficients for exchange between free and complexed solute, D_DH and D_HD. Since D_AB can be determined from experimental results, D_DH and D_HD can be calculated. The results also show the morphology dependence of D_AB. The diffusion coefficient of the free solute D_A also changes with the loading of the complexing agent in the film. This morphology dependence can explain why the gas permeability can decrease when the concentration of the complexing agent increases in the membrane.     

La掺杂钛酸钙光催化剂在可见光下分解水制氢的影响因素

以柠檬酸为络合剂,采用溶胶-凝胶法制备了钙钛矿型光催化剂Ca_{0. 99}La_{0. 01}TiO₃,利用X射线衍射仪(XRD)、扫描电子显微镜(SEM)、紫外-可见漫反射光谱仪(UV-Vis DRS)等对光催化剂材料进行了表征,并考察了N掺杂对光催化剂催化效果的影响,探究了可见光条件下,Ca_{0. 99}La_{0. 01}TiO_3-xN_x在不同Pt负载量及不同种类牺牲剂中光催化分解水的产氢量,并进行相关荧光猝灭分析.结果表明,在可见光条件下,Pt负载量为1%且掺杂N的钙钛矿光催化剂在Na₂SO₃/Na₂S作为牺牲剂时,光催化分解水的产氢量最高.     

负载型铁系钙钛矿催化剂的研究

钙钛矿型复合氧化物是还原烟气中 SO2 的有效催化剂 .对于钙钛矿催化剂的负载化已有过研究报道 [1,2 ] ,但仅限于活性盐溶液对载体或载体改性后的直接浸渍 ,效果并不很好 .本文用溶胶 -凝胶法制备了负载型 Fe系钙钛矿催化剂 ,取得了良好效果 .1　实验部分1 .1　催化剂制备和表征　将工业载体 γ- Al2 O3 破碎筛分为 40～ 6 0目 ,在 6 0 0℃下煅烧 3 h进行活化处理 ,而后分别采用以下 3种方法制备 :(1 )配制适当浓度的 La(NO3 ) 3 和 Fe(NO3 ) 3 溶液 ,用n(La3 + )∶ n(Fe3 + ) =1∶ 1的混合溶液直接对 γ- Al2 O3 浸渍 ,过滤后于 1 2 …     

玻碳电极表面复合配位银电结晶机理研究

以具有实际应用价值的复合配位体系无氰镀银电解液为研究对象, 运用循环伏安和电位阶跃等实验方法, 结合 Scharifker-Hill 经典理论模型分析, 成功获得了Ag在玻碳电极（GCE）表面电沉积的成核机理及成核动力学参数, 并分析了温度对成核方式及成核动力学参数的影响. 结果表明, 该体系下Ag在GCE表面的电沉积是由扩散控制的不可逆过程, 遵循三维瞬时成核生长机理. 随着阶跃电位从-750 mV 负移至-825 mV, 峰值还原电流Im逐渐增大, 达到峰值还原电流所需时间tm逐渐缩短; 扩散系数D变化不大, 基本稳定在（7.61±0.34）×10^-5 cm²·s^-1; 成核密度数N₀则从3.26 ×10⁵ cm^-2提高至10.2×10⁵ cm^-2. 银沉积初期的形貌观察, 验证了其三维瞬时成核生长机理. 提高温度可以显著改善电解液中具备活性的银配位离子的扩散能力, 缩短成核时间, 提升成核密度数N0.     

三正辛胺-二甲苯液膜迁移Cd(Ⅱ)的研究

研究了三正辛胺-二甲苯支撑液膜体系中搅拌速率、反萃剂、三正辛胺浓度、料液中H+浓度等因素对Cd(Ⅱ)离子迁移的影响.用大块液膜测定了不同温度时Cd(Ⅱ)离子跨膜迁移的萃取及反萃取的表观速率常数k₁和k_2.实验表明,温度升高,k₁和k₂均增大(k₁>k₂),且达到膜相最大镉离子浓度时所需的时间逐渐减少.膜相积累的镉离子浓度达最大时,Cd(Ⅱ)离子跨膜传输为稳态传输.根据Arrhenious关系得到膜相萃取反应和反萃取反应的活化能分别为23.8和19.3kJ/mol.     

活度系数法测定A2B型难溶盐的溶度积——以Ag2SO4为例

实验假设水溶液中Ag+和SO42－的浓度非常低时,其活度无论处于同一体系还是在不同体系均相同。依此设计原电池,使该原电池的电池反应为Ag2SO4(s)→2Ag+(aq)+SO42－(aq),采用补偿法测量一定温度下此原电池中AgNO3溶液浓度和K2SO4溶液浓度发生变化时的电池电动势E。依据能斯特方程和Debye-Huckel极限公式,推导出原电池标准电动势E?与电解质的平均活度系数γ±及溶液浓度的关系,用外推法作图得到此电池反应的标准电动势E?。由平衡常数与原电池标准电动势的关系,得到Ag2SO4的溶度积Ksp(Ag2SO4)。     

Mechanism of Phenol Hydroxylation with Hydrogen Peroxide Catalyzed by Iron Complex Oxide

Dihydroxybenzene are both very important chemical products. The oxidation of phenol to produce catechol and hydroquinone has been researched extensively since the 1970s. In this paper, the iron complex oxide was prepared by the air oxidation of aqueous suspension method and the catalytic activities were investigated in the hydroxylation of phenol with H₂O₂ to catechol and hydroquinone. The results showed that the catalyst had higher catalytic activities and the phenol conversion could reach 24% when the phenol/H₂O₂ (mole ratio) was 3 and the catechol/hydroquinone (mole ratio) 1.5 in products. Furthermore, the interaction of the catalyst with H₂O₂ had also been demonstrated by IR spectrometry. In the presence of H₂O₂ a band at 956 cm^-1 appeared and disappeared when the H₂O₂ is replaced by H20 or the catalyst was heated over 373 K, at which temperature decomposition of iron peroxide was very likely. The band at 956 cm^-1 was due to the formation of structure of iron peroxide species and the stretching vibration of surface 0-0 species. The results of IR studies suggested that the catalyst might be react with hydrogen peroxide to form iron peroxide, which decomposed to produce·OOH radical. In the presence of DMPO (5,5-dimethyl-1-pyrroline-N-oxide) the·OH radical was also successfully captured in the hydroxylation of phenol by H₂O₂ over iron complex oxide catalyst in the first time that has been confirmed by means of ESR spectrometry. The results of ESR suggested the process of hydroxylation of phenol with H₂O₂ was probably a radical process. A possible mechanism of the catalytic process was proposed.     

Kinetic–catalytic–spectrophotometric determination of low concentrations of molybdenum in white wines

The paper describes the determination of the molybdenum content in white wines based on its catalytical action on the kalium iodide oxidation by hydrogen peroxide in acid medium.

The optimum reaction conditions (the catalyst, KI and H₂O₂ concentrations, the pH value, the order of the reagent additions, the temperature) have been found by studying the effect of the reaction variables.

The influence of some metallic ions (Ca²⁺, Mg²⁺, Zn²⁺, Cd²⁺, Fe²⁺ and Fe³⁺) and complexing anions (F⁻, C₂O²⁻₄, EDTA⁴⁻) on the catalyzed reaction rate was elucidated.

The molybdenum concentration was estimated by the tangent, fixed-time and fixed-absorbance method. The obtained average values for molybdenum content in white wines are within the 1.77×10⁻⁷–1.83×10⁻⁷ mol l⁻¹ range.     

Synthesis of Silver Nanoparticles Using Complexing Agent Method: Comparing the Effect of Ammonium Hydroxide and Nitric Acid on Some Physical Properties of Nanoparticles

Silver nanoparticles were prepared using complexing agent method in which citric acid was used as the complexing agent. The effect of ammonium hydroxide and nitric acid addition on size, morphology, purity and surface area of nanoparticles were studied and compared. XRD, TEM, EDAX and BET were used for the characterization of synthesized nanoparticles. Addition of ammonium hydroxide led to smaller size of the silver nanoparticles. However, lower purity of nanoparticles was obtained when ammonium hydroxide was added to the mixture. However, the morphology of nanoparticles in both conditions is same. Also the experimental studies of nanoparticles surface areas show their tracking by size as we expected. These effects can be explained by the role of ammonium hydroxide and nitric acid on the direction of equilibrium reaction and affecting the solubility of silver citrate.