Mo/HZSM-5基甲烷非氧化脱氢芳构化催化剂的TPD及TPR研究

在Ｍｏ／ＨＺＳＭ－５基甲烷非氧化脱氢芳构化催化剂中加入促进剂ＺｎＳＯ４，使该催化剂的活性和操作稳定性大为改善．对非促进的Ｍｏ／ＨＺＳＭ－５和促进型的Ｍｏ－ＺｎＳＯ４／ＨＺＳＭ－５甲烷芳构化催化剂的ＮＨ３－ＴＰＤ研究结果表明，促进剂ＺｎＳＯ４的加入大大提高了催化剂表面的Ｂ－酸位浓度；这种Ｂ－酸位能较稳定地存在于催化剂表面，不易流失；催化剂表面高浓度Ｂ－酸位的稳定存在是其甲烷非氧化脱氢催化活性显著提高的关键因素．Ｈ２－ＴＰＲ结果显示，过高的焙烧温度不仅不利于维持催化剂的表面酸性位（尤其是Ｂ－酸位）的浓度，还可能导致催化剂表面Ｍｏ物种的聚集和ＭｏＯ３微晶的生成，使同一Ｍｏ负载量的催化剂中可还原至较低价态的Ｍｏ物种所占比例下降

甲烷脱氢芳构化W/HZSM-5基催化剂EPR研究

利用ＥＰＲ等谱学方法，对Ｗ／ＨＺＳＭ－５基催化剂上Ｗ物种的价态及其在Ｈ２预还原过程中的动态行为进行了表征研究．结果表明，由碱性前驱液制备的Ｗ／ＨＺＳＭ５催化剂在１０７３Ｋ、Ｈ２预还原条件下只能还原产生一类主要Ｗ物种，Ｗ５＋；而由酸性前驱液制备的Ｗ－Ｈ２ＳＯ４／ＨＺＳＭ－５催化剂在相同反应条件下则可还原产生两类共存的Ｗ物种，Ｗ５＋和Ｗ４＋．关联到在相同的甲烷脱氢芳构化（ＤＨＡＭ）反应条件下Ｗ－Ｈ２ＳＯ４／ＨＺＳＭ－５对ＤＨＡＭ反应的催化活性比Ｗ／ＨＺＳＭ－５高得多的实验事实，可以推断，ＤＨＡＭ反应活性与催化剂上较高价态Ｗ物种（Ｗ５＋）的浓度并不存在顺变关系，而与Ｗ４＋物种的浓度则密切相关

FeSi2Ti相重构对工业硅中杂质酸洗行为的影响

为了强化酸洗提纯多晶硅技术,本工作通过FeSi2Ti相重构来提高酸洗的除杂能力。研究结果发现,经Si-Fe-Ti合金精炼之后,工业硅中的主要杂质相由原来的Si-Fe-Al、Si-Al-Fe和Si-Ti-Fe相转变成FeSi2Ti、Si-Ti-F...陕西省“无机高纯硅材料产业创新链”科技项目(2017TSCXL-GY-06-02)~

Removal of Iron During Copper Sulfate Production from Bioleaching Reextraction Solution

［中文文摘］利用三种方法分别对某铜矿山生物浸铜反萃液生产饲料级五水硫酸铜的重要步骤———除铁工艺进行了深入研究,结果表明:采用黄铵铁矾法除铁,控制温度在95℃、pH=1 6,除铁率可以达到91 2%;采用氢氧化铁沉淀法,于70℃,pH=3 8的条件下,除铁率可达98 1%。但上述方法除+、Na+和Ca2+等杂质带入硫酸铜溶液;采用一步结晶法,控制结晶温度在60℃、结铁过程会将NH4晶时间为6h,除铁率可以达98 5%,该工艺操作简单,产品符合饲料级硫酸铜的国家标准。［英文文摘］Iron removal is crucial to the process of feed-additive copper sulfate pentahydrate production from bioleaching reextraction solution.In this paper,three iron removal methods were examined.A series of experiments were conducted in different conditions and the results indicated that when iron was removed by precipitating in the form of ammonium jarosite(95 ℃,pH=1.6),the iron removal efficiency was 91.2%,while by precipitating in the form of ferric hydroxide(70 ℃,pH=3.8),the iron removal efficiency was 98.1% However ,by these two methods ,the use of oxidant and neutralization reagents introduced unwanted NH+4 ,Na + ,Ca2 + into copper sulfate solution. Crystallizating copper sulfate from reextraction solution ,a simple process ,could remove iron effectively without adding any additives and the iron removal efficiency could reach 98.5% under the condition of 60 ℃and 6 h ,and the quality of copper sulfate met national standards of feed additive.福建紫金矿业股份有限公司资助项

Characterization and Electrochemical Investigation of Boron-Doped Mesocarbon Microbeads Anode Materials for Lithium-Ion Battery

本文采用XPS ,SEM ,XRD和电化学充放电测试研究了硼掺杂的中间相碳素微球 (MCMB)的结构和性能 .结果表明掺杂硼提高了MCMB的石墨化程度和晶粒尺寸 ,极大地改变了MCMB的形貌 .电化学充放电实验说明硼掺杂的中间相碳素微球嵌锂过程处于较高的电位 ,并有较大的不可逆容量The anodic performances of boron doped and undoped mesocarbon microbeads(MCMBs) were comparatively studied and the structures were characterized by XPS,SEM,XRD and electrochemical measurements. It was found that boron doping samples greatly increased the degree of graphitization and the crystallite size,leading to quite different morphology. Electrochemical discharge/charge cycle tests indicate that lithium intercalation occurred at a little higher potential for the boron doped MCMBs, being attended by greater irreversible capacity loss.作者联系地址：厦门大学固体表面物理化学国家重点实验室厦门大学化学系!福建厦门361005,厦门大学固体表面物理化学国家重点实验室厦门大学化学系!福建厦门361005,厦门大学固体表面物理化学国家重点实验室厦门大学化学系!福建厦门361005,厦门大学固体表面物理化学国家重点实验室厦门大学化学Author's Address: State Key Lab for Physical Chemistry of Solid Surface, Dept. of Chem., Xiamen Univ., Xiamen 361005, Chin

Preparation and Electrochemical Lithium Intercalation Performance of Segmented Carbon Nanofibers

以泡沫镍为催化剂 ,在 6 0 0和 70 0℃下 ,以CVD法热解乙炔气体制备大量的纳米碳纤维 .随着制备温度增加 ,纳米碳纤维直径变小 ,竹节状含量减少 ,d0 0 2 值减小 ,微晶片层平面Lc 和La 值增大 ,碳材料的可逆容量则下降 .分别用透射电镜、X射线衍射和拉曼光谱观察和测定了纳米碳纤维的形貌、微结构 ,发现在不同条件下生长的纳米碳纤维有不同的形貌和结构 .对纳米碳纤维的电化学嵌锂性能的研究表明 ,纳米碳纤维的结构对其电化学嵌锂容量和充放电循环寿命起重要影响 ,制备温度越低 ,纳米碳纤维的石墨化程度越差 ,可逆嵌锂容量相应要高一些Segmented carbon nanofibers were prepared by pyrolysis of acetylene on foam Ni at 600 and 700℃ in a fixed bed flowed-reactor. The morphology, microstructure and lithium insertion properties of these carbon nanofibers were investigated by TEM, XRD, Raman and electrochemical methods. Through TEM observations, it was found that this kind of carbon nanofibers was composed of lens-like segments with nearly equal separation stacking along the nanofiber axis. When the reaction temperature was 600℃, segmented carbon nanofibers were the major production. However, when the reaction temperature increased to 700 ℃, the content of segmented carbon filaments decreased and their diameter became smaller. The crystallite size d 002 and L c were determined by the 002 carbon Bragg peak of XRD patterns using the Bragg and Scherrer formulas. The intensity ratios of the 1350 cm -1 line and the 1580 cm -1 line (R=I D/I G) was used to evaluate the L a value, which was inversely proportional to the effective crystallite size in the direction of the graphite plane (L a). With the reaction temperature increased, the d 002 value decreased, L a and L c values increased, which indicated the degree of crystallinity increased. Segmented carbon nanofibers were used as positive electrodes of C/Li cells. The first charge capacities of C/Li cells were 480 and 300 mAh/g for samples produced at 600 and 700℃, respectively. The samples at 600℃ showed capacities higher than the theoretical value of graphite, which was attributed to accommodation of more lithium at the edge of graphene layers and on the surface of graphene layers according to the mechanisms of lithium insertion in carbons prepared by low-temperature pyrolysis of hydrocarbons. As confirmed by the XRD and Raman spectra, the samples at 700℃ had larger L a and L c, which led to the capacity decreasing.国家自然科学基金 (6 0 2 710 0 9);; 浙江省自然科学基金 (5 0 110 9,2 0 0 0 5 3)资助项

Preventive effect and mechanisms of 3,3-diindolylmethane on oxidative stress induced by hydrogen peroxide in HaCaT cells

目的:探究3,3'-二吲哚甲烷(dIM)对过氧化氢(H_2O_2)诱导人角质形成细胞(HACAT)氧化应激作用的预防效应及可能机制。方法:体外培养HACAT细胞,用H_2O_2建立氧化应激模型。采用CCk-8法检测不同浓度(1~20μMOl/l)dIM对HACAT细胞生长的抑制作用;流式细胞术检测dIM作用前后细胞内活性氧自由基(rOS)含量的变化;WESTErn blOT检测不同浓度dIM(0、5、10μMOl/l)对HACAT氧化应激相关蛋白核因子(nf-κb)和丝裂原活化蛋白激酶(MAPkS)磷酸化表达水平的影响。结果:成功建立了HACAT氧化应激模型。CCk-8法研究结果显示1-10μMOl/l dIM对HACAT细胞无明显毒性作用(P>0.05);流式细胞术检测结果表明10μMOl/l dIM预处理可有效预防由H_2O_2诱导的HACAT内rOS产生(P0.05).Flow cytometry results indicated that pretreatment with DIM(10 μmol/L) could inhibit the level of intracellular ROS(P<0.05).With increasing concentration of DIM,the levels of p-p38-MAPK,p-JNK and p-NF-κB were significantly depressed.CONCLUSION:DIM could protect HaCaT cells from H_2O_2-induced oxidative stress via suppressing production of ROS levels and down-regulating the expression of NF-κB and members of MAPKs.DIM might be used as an effective drug to treat or reduce oxidative stressmediated injury in skin cells.国家自然科学基金青年基金(81101562); 广东省科技计划项目(2012B060300005); 广东省自然科学基金(S2012010009633

社会系统工程与国家治理体系现代化

2014年3月30日,中国人民大学国家发展与战略研究院社会系统工程研究中心成立暨“社会系统工程与国家治理体系现代化“学术研讨会在中国人民大学逸夫会堂第一会议室举行,来自十余所高校和学术团体的专家、学者和一些媒体的代表参加了会议。现把会议主要发言内容选载如下

Preparation and electrochemical lithium intercalation performance of segmented carbon nanofibers

Segmented carbon nanofibers were prepared by pyrolysis of acetylene on foam Ni at 600 and 700degreesC in a fixed bed flowed-reactor. The morphology, microstructure and lithium insertion properties of these carbon nanofibers were investigated by TEM, XRD, Raman and electrochemical methods. Through TEM observations, it was found that this kind of carbon nanofibers was composed of lens-like segments with nearly equal separation stacking along the nanofiber axis. When the reaction temperature was 600degreesC, segmented carbon nanofibers were the major production. However, when the reaction temperature increased to 700degreesC, the content of segmented carbon filaments decreased and their diameter became smaller. The crystallite size d(002) and L-c were determined by the 002 carbon Bragg peak of XRD patterns using the Bragg and Scherrer formulas. The intensity ratios of the 1350 cm(-1) line and the 1580 cm(-1) line (R =I-D/I-G) was used to evaluate the L-a value, which was inversely proportional to the effective crystallite size in the direction of the graphite plane (L-a). With the reaction temperature increased, the d(002) value decreased, L-a and L-c values increased, which indicated the degree of crystallinity increased. Segmented carbon nanofibers were used as positive electrodes of C/Li cells. The first charge capacities of C/Li cells were 480 and 300 mAh/g for samples produced at 600 and 700degreesC, respectively. The samples at 600degreesC showed capacities higher than the theoretical value of graphite, which was attributed to accommodation of more. lithium at the edge of graphene layers and on the surface of graphene layers according to the mechanisms of lithium insertion in carbons prepared by low-temperature pyrolysis of hydrocarbons. As confirmed by the XRD and Raman spectra, the samples at 700degreesC had larger L-a and L-c, which led to the capacity decreasing

关于“经济发展方式转变进程中的财税政策”的探讨(笔谈)

转变经济发展方式是当前中国的热门话题,而上海在城市发展中又肩负着率先转变的重要任务,在这一意义和背景下,2010年4月24日由上海金融学院学院主办、上海金融学院公共经济管理学院承办的“《中国城市财政发展报告2009/2010:促进‘两个中心’建设的上海城市财政》首发式暨‘经济发展方式转变进程中的财税政策’论坛“在我校举行。与会专家围绕经济发展方式转变进程中的财税政策的“趋势与目标“、“机遇和挑战“、“实施方略“和“地方实践“等四个专题进行研讨,各抒己见,智慧交锋。现将其真知灼见整理摘要与读者分享,以期待更多学者共同关注当前经济发展方式转变进程中的财税政策