丙烯腈与N-乙烯基吡咯烷酮共聚体系对单体竞聚率的影响

利用Kelen—Tudos方法测算丙烯腈(AN)与N—乙烯基吡咯烷酮(NVP)自由基共聚合单体竞聚率，研究了不同反应体系对单体竞聚率的影响。结果发现：在水相悬浮聚合体系中，转化率小于18％时，两单体的竞聚率同DMS0均相溶液聚合结果相近；转化率较大时，同容液聚合结果偏差较大。H2O／DMS0混合溶剂悬浮聚合时，当水含量超过60％(质量比)后，单体竞聚率向水相悬浮聚合结果靠近。溶剂的极性增大，rAN与rNVP值均减小。随反应温度升高，共聚反应向理想共聚方向进行。     

Photocrosslinkable copolymers based on 4‐acryloyloxyphenyl‐3′‐chlorostyryl ketone and methyl methacrylate: synthesis,comonomer reactivity ratios and UV photosensitivity

A new photosensitive acrylate monomer having a pendant chlorocinnamoyl moiety (APCSK) was copolymerized with methyl methacrylate (MMA) in different feed compositions in ethyl acetate solution at 70°C using benzoyl peroxide as a free‐radical initiator. The newly synthesized copolymers were characterized by FTIR, ¹H and ¹³C nuclear magnetic resonance (NMR) spectral techniques, as well as by size‐exclusion chromatography. Their thermal behaviour was assessed by thermogravimetric analysis in air and differential scanning calorimetry under nitrogen atmosphere. The copolymers exhibit no phase separation since there is only one glass transition temperature (T_g) value in the region of copolymer composition studied. The reactivity ratios of the comonomers were calculated by adopting linearization methods such as the Fineman–Ross (F‐R), Kelen–Tudos (K‐T) and extended Kelen–Tudos (ExtK‐T) methods, and by a non‐linear error‐in‐variables model method (EVM) using a computer program (RREVM). The results suggest that MMA is more reactive than APCSK and that their copolymerization leads to the formation of random copolymers. The photosensitivity of the copolymer samples was studied in solution as well as in thin films through UV irradiation. The influence of different factors, including solvent nature, concentration, temperature, photosensitizer and copolymer composition, on the rate of photocrosslinking of the photoreactive copolymers was investigated for effective industrial application of these polymers as negative photoresists. Copyright © 2004 Society of Chemical Industry     

在轻水堆上用模拟机落棒法测量反应性时一种消除空间效应的方法

推出一种以实验为基础，引入理论计算空间通量畸变因子Ｋ的修正公式来消除模拟机落棒法测量反应性空间效应的方法。用两个实例验证了该方法的效果；与脉冲中子源法结果作了比较，符合很好。该修正公式用微机输入参数作在线运算，将使落棒法在保持原有优点的前提下获得满足工程需要的精度。还列举两种典型的Ｋ因子平面分布图来说明其分布的规律，指出寻找到Ｋ在０８至１２之间区域内放置探测器，可得到一次落棒小于±３％的实测精度，而不需作任何修正。     

Differential startle reactivity following central CCK-8S and systemic boc CCK-4 administration in mice: Antecedent stressor history and testing condition.

The influence of intraventricular cholecystokinin-8S (CCK-8S) and systemic N-t-Boc-Trp-Met-Asp-Pheamide (Boc CCK-4) was evaluated in the acoustic and fear-potentiated startle paradigms in CD-1 mice. In the light + tone startle condition, CCK-8S increased startle 168 hrs after administration, compared with saline. In the tone startle condition, CCK-8S decreased startle immediately and 24 hrs after administration, compared with saline. Among nonshocked mice, CCK-8S increased startle at 48 and 168 hrs, compared with saline. In the light + tone condition, 5 μg Boc-CCK-4 did not influence startle, whereas 15 μg Boc CCK-4 decreased startle immediately, 24 hrs, and 48 hrs following administration. Results demonstrate that antecedent environmental experiences interact with subsequent pharmacological challenges in provoking the temporal expression of alterations in startle magnitude. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Psychological Stress Tasks in the Prediction of Blood Pressure Level and Need for Antihypertensive Medication: 9-12 Years of Follow-Up.

Increased blood pressure (BP) reactivity to subtypes of psychological stimuli may differentially predict the development of future BP elevation or hypertension. The authors present the 9-12-year follow-up results of 82 (86%) of 95 male participants with different BP levels. They were healthy, untreated, and age-matched volunteers from a routine health checkup carried out on all 35-, 40-, and 45-year-olds from a medium-sized city. Intra-arterial systolic blood pressure (SBP) during the psychological tasks improved the prediction of future casual SBP and noninvasive 24-hr ambulatory SBP compared with predictions from casual diagnostic measurements. Diastolic blood pressure (DBP) was very useful when added to casual DBP in predicting the need for antihypertensive medication. Reactivity to active tasks especially predicts the need for antihypertensive medication. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The human startle reflex and alcohol cue reactivity: Effects of early versus late abstinence.

This study investigated the human eyeblink startle reflex as a measure of alcohol cue reactivity. Alcohol-dependent participants early (n?=?36) and late (n?=?34) in abstinence received presentations of alcohol and water cues. Consistent with previous research, greater salivation and higher ratings of urge to drink occurred in response to the alcohol cues. Differential salivary and urge responding to alcohol versus water cues did not vary as a function of abstinence duration. Of special interest was the finding that startle response magnitudes were relatively elevated to alcohol cues, but only in individuals early in abstinence. Affective ratings of alcohol cues suggested that alcohol cues were perceived as aversive. Methodological and theoretical implications of the findings are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of iron enrichment with GIC or FeCl3 on the pore structure and reactivity of coking coal

The effect of a Lewis acid addition to a coking coal on the porosity and reactivity towards steam of the resulting iron enriched coal chars are studied. GIC (FeCl₃ graphite intercalation compound) or free FeCl₃ are used as iron containing additives. Coal iron enrichment was performed using either directly FeCl₃ in vapour phase, or by mixing of coal and additives in decaline or by common grinding of coal and additives under argon. Iron enriched coals were carbonized at 750°C (heating RATE = 5°C min) and activation made with pure steam at 800°C to a burn-off off of 50 wt%. The pore structures of coal chars before and after activation were evaluated on the basis of CO₂ and C₆H₆ sorption at 25°C. A significant development of the microporosity is observed in the iron enriched char before activation and its steam reactivity is also increased. After activation, BET surface area values are increased in presence of iron, and porosity is mainly microporous.     

铀氢锆脉冲堆及其在科学技术上的应用

简述了我国铀氢锆脉冲堆的结构和特点及其在科学技术上的应用前景。     

煤结构特征与煤反应活性关系的研究

煤大分子结构特征与煤反应性的关系反映了煤最基本的物理化学性质，对二者关系的研究可为煤加氢、热解等涉及这一领域的煤加工过程研究提供直接的依据和改进操作条件的方案。本文就以上各点综述了近年来对煤结构及煤反应性关系研究的几种主要技术方法及各自的成就，并进行了评述。