苯酚型成青成色剂的活性和结构的关系

本文研究了11个苯酚型成青成色剂的活性和其结构的关系。以T.S.S.(N,N-二乙基对苯二胺硫酸盐)为显影剂,采用外偶法对这些成色剂进行彩色显影,结果证明,其彩色显影动力学符合Elvegard关系式。本研究中,用HMO方法计算了这些成色剂的偶合位置的超离域度S_r^(E)。作为化学活性的表征,研究中发现,此参数能较好地反应成色剂的偶合活性,并发现,成色剂偶合位置的邻位取代基对彩色显影的偶合反应有空间障碍作用。     

释放显影抑制剂型成色剂在彩色影像形成过程中的动力学研究 Ⅱ.DIR和DIAR成色剂对染料影像形成的主反应的影响

继前文测定了成染料成色剂、DIR和DIAR成色剂与QDI的偶合反应的速率常数的基础上,本文进一步研究了DIR和DIAR成色剂对染料影像形成的主反应的作用.研究结果表明其作用(1)DIR或DIAR参与与成染料成色剂竞争QDI的反应,从而控制了QDI在显影银周围的扩散距离,同时也影响了染料的形成速率;(2)DIR和DIAR成色剂在与QDI反应后所释放的显影抑制剂抑制了卤化银的显影进程,从而控制了QDI的形成速率.两种作用的结果都使染料云的尺寸减小.本文还比较了体系中加入等摩尔(mol)量的带有相同抑制基团的DIR或DIAR成色剂的情况下,它们对主反应的影响,结果表明无论是对QDI的竞争作用或对显影的抑制作用,其作用大小都取决于它们与QDI反应的表现速率常数K值.     

明胶层中的扩散和反应的动力学研究——(Ⅲ)水溶性成色剂的偶合反应动力学

利用流动动力学装置跟踪测量技术和数值模拟技术研究了明胶层中水溶性成色剂的偶合反应动力学过程。通过实验结果与反应物在明胶层中边扩散边发生化学反应动力学过程的数值模型计算结果的吻合表明:在明胶层中,当pH不变时,水溶性成色剂的偶合反应是二级反应,并且它虽然带有—C₁₈H₃₇基团,但在明胶中不会形成胶束。本文还分别测定了彩色显影剂CD-2和CD-4的氧化产物在明胶层中的扩散系数以及它们分别与水溶性成色剂WC-1的偶合反应的速率常数。     

有组织介质中的偶合反应Ⅰ.油溶性成色剂的偶合活性

本文采用连续流动装置测量,并配合数值模拟法得到表征五种油珠分散状叔戊酰苯胺型成色剂的油珠偶合活性的偶合反应比速率常数和表观偶合速率常数,同时测定了叔戊酰苯胺型成色剂油珠在胶片层中的照相活性以及表征它们在非水溶液中分子偶合活性的解离常数pKa值,并且比较了上述结果。研究表明,油珠状成色剂的反应规律与分子状成色剂的反应规律是不相同的,这是由于经过“分子组装”后的成色剂油珠在反应时不再以分子为反应单元而是以分子组装体为单元。     

金属离子对彩色成像过程的影响

通过测量和计算彩色单层片中成色剂的照相活性、偶合效率以及漂白前银密度等参数,研究了在分散四当量成色剂青(Ⅰ)时掺入金属离子Mg²⁺、Zn²⁺、Fe³⁺和Cu²⁺对彩色青单层片的成像过程中各个化学反应的影响。本实验的结果表明,成色剂中加入的金属离子Cu²⁺和Fe³⁺对成像过程的初始反应中的Ag影像形成产生不利的影响,但它们能促进偶合过程中青(Ⅰ)与显影剂氧化产物作用所生成的隐色体转变成染料的速率。Mg²⁺和Zn²⁺的加入主要是对偶合过程中青(Ⅰ)的偶合效率产生不利的影响。上述原因的综合影响,最终降低了彩色单层片的感光度。     

二当量成色剂的近代发展

近年来彩色胶卷质量不断提高,体现了高感、微粒、高清晰度及彩色还原好等等优良性能,其中二当量成色剂技术、DIR技术和色罩技术起了重要作用。 众所周知,现代彩色胶片的彩色影像的形成,使用的是彩色显影法。彩色显影的基本反应是四分子的卤化银形成一分子的染料。这样的成色剂称四当量成色剂。     

品马斯克(Mask)成色剂应用研究

彩色负片用品红成色剂在彩色显影时与显影剂氧化物反应形成品红染料。它对绿光有选择吸收,同时对蓝光也存在较大的有害吸收(约占30%)。为了防止由于品红成色剂有害吸收而造成的彩色还原失真,多采用自动马斯克(Mask)技术,即用带色成色剂进行内部校色。     

释放显影促进剂的成色剂(DAR成色剂)的合成和照相性能研究

释放显影促进剂的成色剂即DAR成色剂,是一类以提高感光度为目的的功能性成色剂.DAR成色剂自20世纪80年代初期开发研究至今,对彩色感光材料向高感、微粒方面发展起了举足轻重的作用.DAR成色剂的典型结构可表示为:Cp-L-A,其中Cp代表成色剂母体、L是吸附基团、A是显影促进基团.成色剂母体可以是黄、品、青成色剂和无色化合物4种;吸附基团一般为含氮杂环衍生物,它的主要作用是吸附在卤化银颗粒表面,吸附基团吸附能力的强弱直接影响DAR成色剂的使用效果;显影促进基团常用的是β酰基苯肼类化合物,它的作用是促进显影.     

彩色影像形态学的研究——染料云的形成过程与形态变化

在大颗粒(30—40μm)溴化银晶体上,使用高分散的油溶青成色剂,以CD-3为显影剂进行彩色显影,用显微摄影的方法,观察染料云在形成过程中的形态变化,并用显微密度计对图像进行了扫描。同时,研究了竞争成色剂和DIR成色剂对染料云形态的影响。     

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。     

Multiply Charged Anions,Maximum Charge Acceptance,and Higher Electron Affinities of Molecules,Superatoms,and ClustersSCI北大核心CSCD

The addition of electrons to form gas-phase multiply charged anions (MCAs) normally requires sophisticated experiments or calculations.In this work, the factors stabilizing the MCAs, the maximum electron uptake of gas-phase molecules, X, and the electronic stability of MCAs X^Q-, are discussed. The drawbacks encountered when applying computational and/or conceptual density functional theory (DFT) to MCAs are highlighted. We develop and test a different model based on the valence-state concept. As in DFT, the electronic energy, E(N, v_ex), is a continuous function of the average electron number, N, and the external potential, v_ex, of the nuclei. The valence-state-parabola is a second-order polynomial that allows extending E(N, v_ex) to dianions and higher MCAs. The model expresses the maximum electron acceptance, Q_max, and the higher electron affinities, A_Q, as simple functions of the first electron affinity, A₁, and the ionization energy, I, of the "ancestor" system. Thus, the maximum electron acceptance is Q_{max, calc} = 1 + 12A₁/7(I -A₁). The ground-state parabola model of the conceptual DFT yields approximately half of this value, and it is termed Q_{max, GS} = ${}^{1}\!\!\diagup\!\!{}_{2}\; $ + A₁/(I -A₁). A large variety of molecules are evaluated including fullerenes, metal clusters, super-pnictogens, super-halogens (OF₃), super-alkali species (OLi₃), and neutral or charged transition-metal complexes, AB_mL_n^0/+/-. The calculated second electron affinity A_{2, calc} = A₁-(7/12)(I -A₁) is linearly correlated to the literature references A_{2, lit} with a correlation coefficient R = 0.998. A₂ or A₃ values are predicted for further 24 species. The appearance sizes, n_ap^3-, of triply charged anionic clusters and fullerenes are calculated in agreement with the literature.     

EPR and ESEEM study of the plastoquinone anion radical QA in photosystem II treated at high pH

The effect of treatment at pH = 11 on the photosystem II was studied by EPR and electron spin echo envelope modulation (ESEEM). The magnetic interaction between the semiquinone Q_A^−. and the non-heme Fe²⁺ (S = 2) was absent. ESEEM showed that the Q_A^−. interacts magnetically with two ¹⁴N nuclei. The first interaction has a hyperfine coupling tensor (A_XX, A_YY, A_ZZ)=(2.0, 1.7, 2.3 MHz) and nuclear quadrupole interaction parameters e²qQ/h=3.24 MHz and η = 0.45 while those of the second are (A_XX, A_YY, A_ZZ)=(1.2, 1.5, 2.3 MHz), e²qQ/h = 1.56 MHz and η = 0.71. These are assigned to an amide nitrogen of the peptide backbone and the amino nitrogen of an imidazole respectively. By analogy to the bacterial reaction centre, these nitrogens are attributed to the Ala 261 and His 215 of the D2 protein. It was shown earlier that the imidazole coupling is absent in cyanide-treated PSII, its presence here is attributed to a difference in the position of the imidazole group itself.     

基团贡献法在估算反应热过程中的系统性验证及校正

在进行化工过程危险评估和安全设计时,反应热是一项非常重要的热力学参数。通常情况有两种方法获得反应热：量热法与估算法。相比来说,量热法的结果更精确,但所需时间和费用较多,也经常由于实验条件的限制无法进行;而估算法相比来说更便捷,但结果却不够准确。基团贡献法(GCM)就是一种常见的估算法。为了系统地研究估算法的准确度,从而使其能够在工业生产中对反应热进行初筛,本文分别通过量热实验法和GCM估算得到了包括11种常见反应类型在内的33个反应的反应热,并对结果进行了详细对比;按照反应类型对量热结果(Q_calorimetry)和估算结果(Q_GCM)之间的误差进行了总结;根据相对误差范围,反应类型被分为不同的组从而能够将Q_GCM校正为Q_calorimetry;并且针对不同的反应类型,提出了一些校正系数将QGCM校正为Q_recommended (Q_r),使得GCM在工业应用中,量热方法不方便的时候可以服务生产。最后,本文对误差来源进行了详细的分析,并且为如何能够估算得更准确提出了一些建议。     

Stress relaxation behaviour of dipalmitoyl phosphatidylcholine monolayers spread on the surface of a pendant drop

Dipalmitoyl phosphatidylcholine (DPPC) monolayers were characterised by surface pressure/area isotherms (π/A) and surface dilational rheological parameters at temperatures 20–40°C. The methods used were the Langmuir trough and the pendant drop micro-film balance. The latter allows accurate measurements at higher temperatures and transient drop deformation. Stable DPPC monolayers were found only for low surface pressures, π<15 mN m⁻¹. At higher monolayer compression π decreases over a long time, mainly caused by molecular rearrangement processes in the monolayer starting in the coexisting region. At π>25 mN m⁻¹ and 20°C relaxation experiments give evident of rupturing, brittle monolayer structures. At higher temperatures the monolayers became more fluid-like. π/A-isotherms determined by using both methods principally agree with each other, but show also remarkable differences, which cannot be explained so far satisfactory. Transient drop relaxation experiments were analysed for the short time range (600 s). At 20°C the dilational modulus (_r) and the surface dilational viscosity (ξ_r) passes a stationary maximum at 0.54 nm² molecule⁻¹ and increase strongly at higher surface coverage, thus indicating crystalline monolayer structure. Increasing temperature from 20 to 30°C causes a rapid decrease of _r and ξ_r and a shift of the stationary maximum to lower surface coverage. No evidence for crystalline structure is found. Further increase of temperature causes _r and ξ_r increase again. This increase is caused by a rising relaxation time, while the elasticity does not change in the same manner. Such intermediate decrease of _r and ξ_r in the range 30–40°C appears to be unusual and can be interpreted as a consequence of strong DPPC interactions and strongly pronounced retardation of monolayer deformation. The study is discussed in connection to the physiology of breathing. For pulmonary surfactants the observed behaviour seems to be understandable. It is however interesting that such complex behaviour is observed for monolayers consisting of DPPC only.     

Conformational identification of cyclohexylphosphine by microwave spectroscopy

The microwave spectra of cyclohexylphosphine have been recorded in the 18.0–26.5 GHz region. A-type rotational transitions have been assigned. The ground state rotational constants were determined to be A = 4153.75 ± 0.23, B = 1362.31 ± 0.01 and C = 1104.14 ± 0.01 MHz for C₆H₁₁PH₂, and A = 4030.03 ± 0.25, B = 1312.72 ± 0.01 and C = 1072.33 ± 0.01 MHz for C₆H₁₁PD₂. From the experimental rotational constants, it is suggested that the assigned spectra have resulted from the chair conformation with the gauche phosphine group in an equatorial position (CESG). This form is believed to be the most populated conformational isomer in the gas phase.     

The effect of replacing a benzene ring with a saturated six-membered ring on the mesomorphic properties of 4,4'-disubstituted diphenyldiacetylenes

A limited selection of ring modified diphenyldiacetylenes of the type where A=, Y=C_nH_2n+1, CF₃, F, COMe, NH₂, and NMe₂, and A=, trans and cis with Y=F and trans with Y=C₃H₇, were synthesized. Mesomorphic properties were determined by hot stage polarizing microscopy and DSC. These properties were generally poorer than those found in the parent benzene compounds. This was also true of some pyrimidine analogues reported earlier. Birefringence values also decreased as expected.     

Amphiphile bilayer films from DPPC: bilayer lipid membranes and Newton black films

Amphiphile bilayer films are obtained from 1,2 dipalmitoyl-glycero-3-phosphocholine (DPPC): bilayer lipid membranes (BLM) and Newton black films (NBF), through thinning of the respective thin liquid films, thus allowing for a very precise determination of the moment of their formation. Stability (or rupture) and formation of BLM and NBF are considered from a unified point of view with the microscopic theory of Kashchiev–Exerowa [J. Colloid Interface Sci., 77 (1980) 501–511], based on the formation of nanoscopic holes in them. BLM and NBF are obtained and studied with the microinterferometric method of Scheludko–Exerowa in its contemporary version. The equivalent thickness of both BLM (in benzene solution between two water phases with 0.1 M NaCl) and NBF in aqueous DPPC solution (in the presence of 0.1 M NaCl) is determined as being h_w = 7.0 nm for BLM and h_w = 7.8 nm for NBF. By means of the dependences: BLM lifetime versus DPPC concentration and probability for BLM formation versus DPPC concentration, it is established that there exist metastable BLM and stable NBF. The good fit between the experimental results of τ(C) dependence and theory in the case of BLM allow to determine the three constants: pre-exponential factor A = 1.5 × 10⁻³ s, related to the process kinetics; constant B = 20.2 ± 0.2, related to the specific hole energy γ = 1.7 × 10⁻¹¹ J/m and the equilibrium concentration C_e = 6 × 10⁻⁴ ± 7.2 × 10⁻⁶ m/l. The specific hole linear energy γ = 1.7 × 10⁻¹¹ J/m determined as well as the binding energy Q between first neighbor molecules in the bilayers Q = 1.48 × 10⁻¹⁹ J (36 kT) are lower than the ones determined for DPPC foam bilayer in gel state γ = 9.1 × 10⁻¹¹ J/m and Q = 55 kT. This means that interaction is weaker in the case of BLM. The critical concentration C_c at which bilayer formation starts is: for BLM C_c = 30 μg/ml and for NBF C_c = 70 μg/ml. This concentration characterizes quantitatively the formation of the amphiphile bilayer and is a very useful parameter that can be used for various purposes.     

碰撞能对K(2S)+HF(X1Σ+)→KF(X1Σ+)+H(2S)反应的影响

基于Sayós等构建的基态势能面, 运用准经典轨线方法对原子-分子反应K(²S)+HF(X¹∑⁺)→KF(X¹∑⁺)+ H(²S)的立体动力学性质进行了研究. 计算了该反应的极化微分反应截面、 两矢量k?j'相关分布函数P(θ_r)、 三矢量k?k'?j'相关分布函数P(?_r)和空间分布函数P(θ_r,?_r). 结果表明, 产物KF的转动角动量j′不仅在垂直于反应物相对速度矢量k的方向上有强烈的取向效应, 而且还定向于y轴的负方向, 转动角动量j′敏感地依赖于碰撞能.     

Influence of molecular weight on the thermal decomposition of hydroxyl terminated polybutadiene

Thermogravimetric analysis of hydroxyl terminated polybutadiene (HTPB) and its fractions of different molecular weights separated by preparative GPC shows two major stages of weight loss of different nature in a nitrogen atmosphere. The first stage is primarily depolymerisation, cyclisation and crosslinking of molecules and the second stage is mainly the decomposition of the residue from the first stage. The kinetic parameters, viz. activation energy E and pre-exponential factor A using four different non-isothermal integral equations show a systematic increase with increase in molecular weight for the first stage, whereas for the second stage, the effect of molecular weight on E and A values is not prominent. The increase in E and A values for the first stage is attributed to the formation of greater number of cyclised and crosslinked products from molecules of higher dimensions. Quantitative correlations between the kinetic constants and the molecular weight parameters were derived for the first stage as a quadratic curve following the equation: E or ln A = K₁ − K₂/M (where K₁ and K₂ are empirical constants whose values are different for the different molecular weight averages, viz. M_n, M_w and M_z and for the different equations).