ZnO对MRP／NE阻燃ABS体系的协同作用

采用微胶囊化红磷（MRP）和酚醛环氧树脂（NE）复配阻燃剂,以ZnO为阻燃增效剂,制备了具有良好阻燃性能的无卤阻燃ABS。研究了ZnO用量对ABS阻燃性能的影响及其协同作用机理。结果表明：添加ZnO即可显著提高材料的阻燃性能。当MRP／NE／ZnO添加量分别为9％、21％和4％时,阻燃PP的氧指数达34％。TGA、FTIR和体视显微镜分析结果表明：添加ZnO可以催化MRP／NE间的酯化交联反应．促进材料成炭,增加残炭含量。提高阻燃性能。     

金属化合物对膨胀阻燃乙丙弹性体的影响

以多聚磷酸铵（APP）与新型三嗪类成炭剂（CNCA-DA）复配成新型膨胀型阻燃剂（IFR）,将其应用在乙丙弹性体中（EP）,并采用氧指数测定仪（LOI）、热重分析仪（TGA）和红外光谱（FTIR）研究了碳酸镍（NC）和硼酸锌（ZB）与EP／IFR体系阻燃性能的影响。结果表明,用1％的金属化合物替代1％的IFR后,复合材料的氧指数值都有一定程度的改善,其中NC的效果较好,达到27．6％;TGA分析结果表明,金属化合物都能促使复合材料保留更多的残炭;FTIR分析表明,金属化合物能促使残炭中形成了聚芳烃和P—O—C、P—O-P的交联结构。     

PP/IFR/ZB体系的热降解动力和残炭结构分析

将硼酸锌(ZB)添加膨胀阻燃聚丙烯体系(PP/IFR)中,利用热重分析仪(TGA)、X-射线荧光光谱仪(EDX)和红外光谱仪(FTIR)分析了该膨胀阻燃体系的热降解动力学和残炭的化学结构。结果表明,添加ZB后,PP/IFR体系提前分解,但保留了更多的残炭;EDX和FTIR分析结果表明,残炭中保留了更多的磷,且少量的ZB能促使IFR发生酯化反应,形成更多P-O-P和P-O-C的交联结构,从而提高材料的阻燃性能。     

4A分子筛对PP/IFR体系性能的影响

研究4A分子筛对膨胀阻燃聚丙烯复合材料力学性能、吸潮性能和热降解性能的影响。结果表明:添加少量的4A分子筛对膨胀阻燃聚丙烯复合材料的力学性能影响不大;阻燃剂的加入对吸潮率有一定的升高;TGA分析结果表明:无论在氮气还是空气气氛下,4A分子筛均改变了PP/IFR的热降解行为,促使PP/IFR在高温阶段加快分解,但在后期能形成更多的炭层,并在残炭中保留更多的磷。     

阻燃羊毛纤维的热稳定性研究

用氟钛酸钾与钒酸盐、钼酸盐组成的阻燃体系对羊毛纤维进行阻燃处理,所得的羊毛纤维用热分析、剩碳率、氧指数等分析方法对其热降解行为进行研究.实验证明：经过阻燃处理的羊毛纤维剩碳率和氧指数升高,阻燃性能增强.根据阻燃羊毛纤维的热降解行为的变化,对不同的阻燃剂的阻燃机理做了初步的探讨.     

金属化合物对LDPE／IFR体系热降解行为的影响

以多聚磷酸铵（APP）与自制齐聚物式成炭剂（OCA）复配成新型膨胀型阻燃剂（IFR）,采用热重分析仪（TGA）研究硼酸锌（ZB）和二氧化锰（MnO2）对LDPE／IFR体系热降解行为的影响。结果表明,氮气气氛下,金属化合物都能促使复合材料形成更多的残炭,但对热降解活化能的影响不明显;空气气氛下,MnO2可减缓材料的初始降解,使复合材料寿命延长,而ZB则使复合材料初始降解延长,寿命缩短。     

碳酸镍协同阻燃聚丙烯的热降解行为

碳酸镍对多聚磷酸蜜胺（MPP）和笼状季戊四醇磷酸酯（PEPA）复配阻燃聚丙烯体系具有较好的阻燃协同作用。采用TGA、FTIR研究了碳酸镍（NC）对阻燃聚丙烯的热降解行为,并用Flynn-Wall方法模拟体系的热降解动力学。TGA测试表明NC能有效地增加材料的残炭含量;FTIR和热降解活化能分析结果表明在降解过程中,NC能促使材料生成更多的P—O—C和P—O—P的交联结构,并提高材料的热降解活化能。     

PP/IFR/ZnO体系的热降解机理研究

采用TGA、EDX和Kissinger法活化能计算分析了ZnO催化阻燃聚丙烯体系的热降解过程并提出其机理。TGA分析结果表明：ZnO使体系的初始降解温度降低,热降解提前,但是热降解速率减缓;Kissinger法活化能计算结果表明：添加1%的ZnO后,体系的表观活化能增大;EDX结果表明：ZnO的加入促使残炭中保留了更多的P。     

膨胀阻燃聚丙烯的热降解动力学研究

利用双辊混炼机制备了共混型阻燃聚丙烯(PP)材料,并用热重(TG-DTG)方法研究了PP、PP/MPP和PP/MPP/PER在N2气氛下以不同升温速度时的热降解动力学行为,以此探讨阻燃性能与热降解行为的关系。试验发现,加入阻燃剂后材料的初始分解温度提前。利用Kissinger法和Flynn-Wall法求取了材料的活化能,发现两种方法求取的结果相一致。添加阻燃剂后,材料的活化能明显提高,说明阻燃剂使PP提前分解成炭,产生隔热、隔氧作用,阻止了PP的进一步氧化分解。采用Crane方程求得材料热降解反应级数均接近1。     

成核剂对聚烯烃的结晶和力学性能的影响

本文利用加入各种类型的成核剂的方法得到了不同结晶形态的聚乙烯(PE)和聚丙烯(PP);用偏光显微镜研究了各种成核剂的成核作用和结晶形态;用显微激光分析仪和差动热分析(DSC)研究了各成核剂对结晶和熔融过程的依赖关系,并测定了它们对结晶度的依赖关系,研究了它们对拉伸力学性能的影响。研究结果表明,成核剂可以明显地使晶粒细而均匀,能改变结晶和熔融速率,以适应各种工艺性要求,但对力学性能的影响较小,因此可以根据工艺和使用要求选用不同的成核剂。     

MPP／PEPA复配阻燃PP的制备及其热降解动力学研究

利用双辊混炼机制备了共混型阻燃聚丙烯（PP）材料,并用热重（TG—DTG）方法研究了PP、PP／MPP、PP／PEPA和PP／MPP／PEPA在N2气氛下以不同升温速度时的热降解动力学行为,以此探讨阻燃性能与热降解行为的关系。试验发现,加入阻燃剂后材料的初始分解温度降低。利用Kissinger法和Flynn-Wall法求取了材料的活化能,发现两种方法求取的结果相一致．添加阻燃剂后,材料的活化能均比PP高。说明阻燃剂使PP提前分解成炭．产生隔热、隔氧作用,阻止了PP的进一步氧化分解。     

多重固化EA/纳米SiO_2杂化涂层的阻燃及热稳定性

以改性纳米SiO2、γ-甲基丙烯酰氧基丙基三甲氧基硅烷(KH-570)、磷酸酯三丙烯酸酯(TEAP)及TDI-TMP加成物作紫外(UV)配方体系的功能成分,制备了含P、N及Si三重固化丙烯酸酯涂层。通过红外、紫外-可见、热重及阻燃性能测试仪等研究了不同阻燃体系下不同固化方式对环氧丙烯酸酯(EA)涂层阻燃及热稳定性能的影响。结果表明:EA体系双键转化率随纳米SiO2含量及固化重数的增加而提高;可见光透过率随KH-570、TDI-TMP的加入而改善;涂层阻燃及热稳定性随阻燃成分与其含量,及固化重数的增加而提高。     

四—（4—氯）苯基卟啉在醋酸中电子吸收光谱研究

研究了四 - (4-氯 )苯基卟啉 [H2 T(4-Cl)PP]在醋酸中电子吸收光谱 .结果表明 ,四 - (4-氯 )苯基卟啉在冰醋酸中以二酸形式 [H4T(4-Cl)PP] 2 和游离碱 [H2 T(4-Cl)PP]形式存在 ,二者之间存在着电离平衡 :[H4T(4-Cl)PP] 2 =[H2 T(4-Cl)PP] 2H     

Biotransformation of nitro-polycyclic aromatic compounds by vegetable and fruit cell extracts

Extracts from various vegetables and fruits were investigated for their abilities to reduce nitro-polycyclic aromatic hydrocarbons (NPAHs). The extracts from grape and onion exhibited an interesting selectivity, yielding corresponding hydroxylamines or amines as major products under mild conditions of 30 °C and pH 7.0. Grape extracts reduced the 4-nitro-1,8-naphthalic anhydride with the highest conversion rate (>99%) and the highest ratio of hydroxylamine to amine (95:5). In contrast, the onion extracts reduced 4-nitro-1,8-naphthalic anhydride with a conversion rate of 94% and a ratio of hydroxylamine to amine of 8:92. The thiol-reducing agent, β-mercaptoethanol, and metal cations, Ca²⁺ and Mg²⁺, greatly increased the reductive efficiency. This work provides an alternative strategy for biotransformation of nitro-polycyclic compounds.     

Influence of surface roughness on the color of dental-resin composites

This study deals with the influence of surface roughness on the color of resin composites. Ten resin composites (microfilled, hybrid, and microhybrid) were each polished with 500-grit, 1 200-grit, 2 000-grit, and 4 000-grit SiC papers. The roughness parameter (R _a) was measured using a Plμ confocal microscope, and field-emission scanning electron microscope (Fe-SEM) images were used to investigate filler morphology. Color was measured using a spectroradiometer and a D65 standard illuminant (geometry diffuse/0° specular component excluded (SCE) mode). Surface roughness decreased with grit number and was not influenced by filler size or size distribution. A significant influence of R _a on lightness (L*) was found. Lightness increased with decreases in roughness, except for specimens that underwent polishing procedure 4 (PP4; 500-grit, 1 200-grit, 2 000-grit, and 4 000-grit SiC papers consecutively). Generally, it was found that surface roughness influenced the color of resin composites. The composites that underwent PP1 (500-grit SiC paper) exhibited significant differences in chroma (C*), hue (h°), and lightness (L*) compared to composites that underwent PP3 (500-grit, 1 200-grit, and 2 000-grit SiC papers consecutively) and PP4. Color difference (ΔE*) between the polishing procedures was within acceptability thresholds in dentistry.     

表面处理对坚果壳粉化学结构和热稳定性的影响

对核桃壳、杏壳和开心果壳3种坚果壳粉分别进行碱、酸和硅烷偶联剂处理,用傅立叶变换红外光谱（FTIR）表征处理前后坚果壳粉化学结构的变化,用热重分析（TGA）测定处理前后坚果壳粉的热稳定性和残炭率的变化．实验结果表明：碱处理可除去半纤维素,使坚果壳粉的木质素质量分数提高,残炭率提高;酸处理可除去部分半纤维素,使残炭率有一定提高;硅烷偶联剂可与核桃壳粉的羟基发生化学反应．     

Anatomy education in a changing medical curriculum in India: Medical student feedback on duration and emphasis of gross anatomy teaching

Authors report here a survey of medical student feedback on the effectiveness of two different anatomy curricula at Christian Medical College, Vellore, India. Undergraduate medical students seeking the Bachelor in Medicine and Bachelor in Surgery (M.B.B.S.) degrees were divided into two groups by the duration of their respective anatomy curriculum. Group 1 students had completed a longer, 18‐month curriculum whereas Group 2 counterparts followed a shorter, 12‐month curriculum. Students' responses to a questionnaire were studied. Analysis of feedback from Groups 1 and 2 contrasted the effectiveness of the two anatomy curricula. The coverage of gross anatomy was rated adequate or more than adequate by 98% of Group 1 and 91% of Group 2. A desire for greater emphasis on gross anatomy teaching was expressed by 24% of Group 1 and 50% of Group 2 (P = 0.000). Two‐thirds of all students felt that the one‐year program was not adequate, and 90% of Group 1 and 74% of Group 2 felt that clinically oriented anatomy teaching required more emphasis. Dissection was helpful or very helpful for 94% of Group 1 and 88% of Group 2. This study suggests that a better understanding of gross anatomy was gained from a course of longer duration (18 months with 915 contact hr vs. 12 months with 671 contact hr). Students who completed the longer anatomy course had greater appreciation of the need for clinically oriented anatomy teaching and dissection. Anat Sci Educ 2:179–183, 2009. © 2009 American Association of Anatomists.     

A novel organosilicon-based ionic plastic crystal as solid-state electrolyte for lithium-ion batteries

A novel organosilicon-based ionic plastic crystal, N,N,N,-diethylmethyl-N-[(trimethylsilyl)methyl]ammonium bistrifluoromethane sulfonimide ([DTMA][TFSI]) was designed and synthesized as solid-state electrolyte for lithium-ion batteries. The chemical structure and the physical and electrochemical properties were characterized in detail. The ionic conductivity of [DTMA][TFSI] was improved significantly by doping with lithium oxalyldifluoroborate (LiODFB) and propylene carbonate (PC). An optimized plastic crystal composite ([DTMA][TFSI]:LiODFB:PC=8:1:1 in molar ratio) as a solid-state electrolyte exhibited a decent cycling stability in LiFePO₄/Li half-cell, with a specific discharge capacity of 144 mA·h/g and capacity retention of 94% after 50 cycles at C/20.     

Effects of partial vs consistent reward in noncontingent pairings of stimuli with reward: A noncontingently produced positive contrast effect

Rats received pairings of two stimuli with reward noncontingently in the Skinner box. During noncontingent pairings, the bar was immobilized. For Group CC 100% of the presentations of both stimuli were rewarded (S₁ ±, S₂ ±), for Group PP 50% of the presentations of each stimulus were rewarded (S₁, ±, S₂±), and for Group PC one stimulus was followed by reward on 50% of its presentations, while the second stimulus was followed by reward on 100% of its presentations (S₁ ±, S₂ ±). A fourth group received the stimuli and reward nonpaired. In a subsequent rewarded test phase, the response facilitating effects of the stimuli were evaluated. In the test phase all groups that received reward paired with S₁, and S₂ performed better in the presence of S₁ and S₂ than the group for which the stimuli were not paired with reward. For groups that received the stimuli paired with reward, a difference due to schedule of reward occurred when schedule of reward was varied within Ss (Group PC), but not when varied between Ss (Group PP vs Group CC). The specific form of this finding was that Group PC’s performance in the presence of S₂ ± was more vigorous than its performance in the presence of S₁ ± and was more vigorous than the performance of Groups PP and CC to S₂. Group PC’s performance to S₁ ± did not differ from that of Groups PP and CC to S₁.     

2-苯甲酰基-4-苯基-2-噁唑啉铜（Ⅱ）配合物的合成和晶体结构

通过实验合成了标题化合物[Cu（L）2]（L=2-苯甲酰基-4-苯基-2-噁唑啉）,并通过元素分析、红外光谱、X射线衍射对其单晶结构进行了测定。该配合物属于三斜晶系,空间群P-1,分子量Mr=594.11,晶胞参数a=0.6099（2）nm,b=1.1082（4）nm,c=1.1331（4）nm,V=0.6753（4）...