碳包覆铁纳米金属颗粒的制备

以酚醛树脂为碳源,硝酸铁为催化剂大量制备碳包覆铁纳米金属颗粒。利用扫描电子显微镜（SEM）、透射电子显微镜（TEM）、高分辨透射电子显微镜（HRTEM）等方法,分析和表征了产物的微观形貌和结构。结果表明：产物为纳米级的准球形碳一铁核壳结构,由同心碳纳米石墨壳层包覆纳米铁组成。产物外径30～100nm,碳层间距为0．34mm,与石墨层间距非常接近。     

碳纤维及无机纤维

20065164碳纳米纤维材料的制法本田摩托;JP2004-211239(2004.7.29)(日)碳纳米纤维与加热可除去的液态热固性粘合树脂混合,该流动的共混物单轴拉伸可得到碳纳米纤维沿着长度方向取向的产品,然后加热处理除去粘合树脂得到碳纳米纤维束。液态热固性树脂在产品成形后固化可作为增强     

季铵盐-高岭石系列插层复合物的制备及结构表征

通过多次置换插层反应,以高岭石/甲醇插层复合物为中间体,将不同链长季铵盐分子插入高岭石层间,对其结构、形貌和插层机理进行了探讨。结果表明:季铵盐分子在高岭石层间主要以全反转式构形存在,季铵盐碳链长度对其插层复合体的结构和形貌具有明显控制作用。碳原子数小于8的季铵盐在高岭石层间以单层平卧形式存在,其形成的高岭石插层复合体晶形仍为片状;碳原子数大于等于8的季铵盐在高岭石层间呈石蜡型倾斜双层形式排列,且碳链与高岭石(001)晶面的夹角随碳原子数增大而减小。碳原子数大于等于8的季铵盐进入高岭石层间,将导致高岭石晶层的卷曲,形成纳米卷或管,且随季铵盐碳链长度增加,高岭石片层卷曲程度加深,纳米卷的数量增多。     

云母粉在丁苯橡胶中的分散性和界面特征

研究粒级分别为0~5,5~10,10~20μm的3种改性云母粉在丁苯橡胶(SBR)中的分散性和界面特征。结果表明:云母粉对SBR的补强性能与云母粉的粒级和径厚比有关,5~10μm云母粉粒级较小,径厚比较大,补强效果较好;0~5μm云母粉在SBR中分布较均匀,以垂直于断面的方向定向排列,断面上存在孔洞;5~10μm云母粉在SBR中一部分以垂直于断面的方向排列,另一部分以平行于断面的方向定向排列,平行排列的云母粉粒径较小,片状云母粉层与层之间被小粒径云母粉填充,可实现紧密堆积并吸收部分应力,提高云母粉对SBR的补强效果;10~20μm云母粉在SBR中只有小部分以垂直于断面方向排列,补强效果较差。     

一种新颖结构的煤基定向碳薄膜的制备与表征

以宏源精选煤为原料在微波等离子体条件下制备出一种新颖结构的碳材料,运用场发射扫描电子显微镜、透射电子显微镜和能量色散谱技术对产物进行表征.结果表明：产物形状似莴笋状,外层石墨化程度较好,其最大宽度约为170 nm,长度则为4～5 μm,且呈定向排列.这种新颖结构的纳米碳材料有望在场发射、增强材料等方面显示出巨大的应用潜力.     

包裹定向排列纳米氯化银的二氧化硅纳米纤维

介绍了一种通过静电作用合成AgCl–SiO2复合材料的新方法. 这种方法能够制备出线条均匀的纳米二氧化硅纤维，直径范围在30~100 nm，纤维的长度大于20 mm. 所包裹的AgCl纳米粒子在纤维中呈规则排列. 沿着二氧化硅纤维生长方向，同一条二氧化硅纤维包裹多条氯化银纳米线.     

具有可控sp~3/sp~2碳原子比例的多层碳纳米片研制

以人造金刚石为原料,通过解理面机械剥离粉碎分选制备工艺成功制备出了一种多层结构的碳纳米片。利用X射线粉末衍射(XRD)、透射电子显微镜(TEM)、扫描电子显微镜(SEM)、激光拉曼光谱(Raman)、固体核磁(MAS NMR)等对其进行了表征分析,发现制备出了一种物相构成为多层结构的碳纳米片,该碳纳米片是由金刚石解理面(111)晶面剥离粉碎而形成的,且含有不饱和碳sp~2杂化碳,形成了sp~3和sp~2混合杂化的结构,并且粒度不同sp~3碳与sp~2碳的比例也不同。     

简捷微波合成氧化锌纳米棒

以氯化锌和乙二胺的水溶液为前驱体溶液,采用家用微波炉微波辐照8min,成功制备出结晶性好的半导体ZnO纳米棒.用X-射线衍射(XRD)、选区成份分析(EDS)、场发射扫描电子显微镜(FESEM)、透射电子显微镜(TEM)和选区电子衍射花样(SAED)对产物进行了表征.结果表明,纳米棒沿着c轴择优取向生长,直径在50nm左右,长度在400～600 nm之间,粒径分布均匀.并对ZnO纳米棒的生长过程进行了简单分析.     

用高分辨透射电子显微技术研究0.94(Na1/2Bi1/2)TiO3-0.06BaTiO3的有序结构

用高分辨透射电子显微技术(high resolution transmission electron microscopy, HRTEM)和选区电子衍射(selected electron diffraction, SAED)技术对具有A位复合钙钛矿结构的0.94(Na1/2Bi1/2) TiO3(BNT)-0.06BaTiO3(BNBT6)陶瓷的显微结构进行了深入研究.沿[001],[011]和[111]3个晶带轴方向的SAED花样分析结果表明:A位Bi3 和Na 可以形成2种不同的有序结构──1/2{110}和1/2{111}超结构.据此,建立了BNT的1/2{110}和1/2{111}有序结构模型,其中1/2{110}型有序是由Bi3 层和Na 层沿[110]方向交替排列而形成,1/2{111}型有序是由Bi3 层和Na 层沿[111]方向交替排列而形成.利用多层法,通过计算机模拟了1/2{111}有序结构沿[001],[011]和[111]3个方向的HRTEM像,与实验拍摄的HRTEM像对照,验证了所建立的1/2{111}有序结构模型的正确性.同时,采用快速Fourier变换(fast Fourier transformation, FFT),由1/2(330)和1/2(330)超晶格反射斑点获得的一维晶格像,揭示了沿[110]方向局部Bi3 层和Na 层扭曲导致的位错和反相畴界(anti-phase boundary, APB), APB的存在表明结构中存在着Bi3 层和Na 层沿[110]方向的交替排列,证实BNBT6中存在着1/2{110}有序结构.BNBT6有序结构的HRTEM研究表明:A位Bi3 和Na 的化学有序是导致超晶格反射的主要原因.     

取向性羟基磷灰石纳米片的合成与分析

采用机械球磨法,以乙醇做球磨介质,成功合成具有结晶取向性的羟基磷灰石(hydroxyapatite,HA)纳米片。采用X射线衍射、场发射扫描电子显微镜和透射电镜等表征方法对HA纳米片的结构进行了分析。结果表明:HA纳米片晶体为单晶结构,其宽度在200～400nm,厚度为50nm。球磨过程中,乙醇分子通过氢键作用,较易在HA晶体的(001)面上发生吸附并延缓该方向的生长,使(001)面成为显露面,最终得到沿(001)面定向排列的片状HA纳米晶。     

快速增长

今年上半年,我国国民经济发展速度为11.5%,全国许多行业仍在快速增长,轮胎业也不例外。从中国橡胶工业协会轮胎分会对45家企业的统计数据看,今年上半年,轮胎产量、出口量继续呈两位数增长,与去年同期相比,轮胎价格有所提高,天然橡胶     

平稳增长

上半年，虽受到能源及原材料价格上涨、用工成本提高、人民币升值、出口退税降低等因素的影响，但橡胶行业经济运行整体仍保持了平稳增长的发展势头，橡胶消耗稳定上升，主导橡胶产品产量比上年都有较大幅度增长，橡胶产品出口继续保持增长，虽趋缓明显，但符合国家经济工作中提出的“全力保持经济平稳较快发展”、“保持对外贸易平稳增长”的调控要求。下半年，国内外经济形势不容乐观，因此，中国橡胶工业协会要求橡胶企业在克服上述诸多困难的同时，要积极寻求市场新的经济增长点，加快调整橡胶产品结构，将企业经济运行质量提高到一个更新水平。详见本期“协会视窗”。     

平稳增长

全球金融风暴使中国经济受到了冲击,我国橡胶行业面临严峻挑战,深感严冬来临,在中橡协七届一次主席团会议上,大家在呼吁政策支持的同时,更着重交流了如何练好内功,共同渡过难关。近期,国家财政部、工业和信息化部、国土资源部、人力资源和社会保障部等各部委纷纷出台措施,扩大内需,保经济增长。最近,国家提高了轮胎等橡胶制品的出口退税率,将对行业困难有一定程度的缓解。     

植物源生长调节剂对小麦生理生长的影响

用浓度均为100mg/L的植物源生长调节剂(T)、赤霉素(GA3)和油菜素内酯(BR)分别在小麦苗期、拔节期、孕穗期、灌浆期进行叶面喷洒,清水对照(CK)。结果表明,植物源生长调节剂、赤霉素和油菜素内酯分别使小麦叶片中叶绿素含量较对照平均增加了10.77%、4.95%、5.54%;使叶片可溶性糖含量分别平均增加了23.83%、16.65%、14.66%;硝酸还原酶(NR)活性平均提高16.14%、18.26%和12.32%,而对类黄酮含量的影响不明显。这说明植物源生长调节剂能够延缓叶片衰老,促进光合作用,延长叶片对氮素的利用和转化时间,促进同化物质的积累,对小麦的生理生长具有明显的促进作用。     

Grain Growth in Sintered Uranium Dioxide: II, Columnar Grain Growth

Evidence is presented which shows that columnar grains can be induced to grow in high-density sintered uranium dioxide specimens by applying a steep temperature gradient at temperatures above 1700°C but below the melting point of 2800°C. Columnar growth apparently is a result of the migration of large transverse voids, whose individual widths define the cross sections of the grains, up a temperature gradient by a sublimation process. The grains grown by this process have a (111) preferred orientation along their columnar axis. A consequence of such void migration in operating fuel elements containing solid UO₂ pellets is the formation of a central void bounded by a region of oxide exhibiting columnar growth.     

Grain Growth in Sintered Uranium Dioxide: I, Equiaxed Grain Growth

Grain growth was investigated in a UO₂ sinter of 94%) theoretical density over the temperature range 1555° to 2440°C. The results were in close, but not exact, agreement with a theoretical expression describing grain growth with a poly-crystalline matrix. For the material studied the mean grain diameter D (μm) after annealing for t hours at a temperature T (°K) was given by the equation

where D₀ and K₀ are, respectively, the initial grain size and a proportionality constant. Uranium metal was found in all specimens annealed above 2000°C. This was taken as evidence that the UO₂ lattice can be oxygen-deficient at high temperatures.     

Growth Hormone Enhances Arachidonic Acid Metabolites in a Growth Hormone Transgenic Mouse

In a transgenic growth hormone (GH) mouse model, highly elevated GH increases overall growth and decreases adipose depots while low or moderate circulating GH enhances adipose deposition with differential effects on body growth. Using this model, the effects of low, moderate, and high chronic GH on fatty acid composition were determined for adipose and hepatic tissue and the metabolites of 20:4n-6 (arachidonic acid) were characterized to identify metabolic targets of action of elevated GH. The products of Δ-9 desaturase in hepatic, but not adipose, tissue were reduced in response to elevated GH. Proportional to the level of circulating GH, the products of Δ-5 and Δ-6 were increased in both adipose and hepatic tissue for the omega-6 lipids (e.g., 20:4n-6), while only the hepatic tissues showed an increase for omega-3 lipids (e.g., 22:6n-3). The eicosanoids, PGE₂ and 12-HETE, were elevated with high GH but circulating thromboxane was not. Hepatic PTGS1 and 2 (COX1 and COX 2), SOD1, and FADS2 (Δ-6 desaturase) mRNAs were increased with elevated GH while FAS mRNA was reduced; SCD1 (stearoyl-coenzyme A desaturase) and SCD2 mRNA did not significantly differ. The present study showed that GH influences the net flux through various aspects of lipid metabolism and especially the desaturase metabolic processes. The combination of altered metabolism and tissue specificity suggest that the regulation of membrane composition and its effects on signaling pathways, including the production and actions of eicosanoids, can be mediated by the GH regulatory axis.     

Isoprocurcumenol Supports Keratinocyte Growth and Survival through Epidermal Growth Factor Receptor Activation

Although proliferation of keratinocytes, a major type of skin cells, is a key factor in maintaining the function of skin, their ability to proliferate tends to diminish with age. To solve such a problem, researchers in medical and skin cosmetic fields have tried to utilize epidermal growth factor (EGF), but achieved limited success. Therefore, a small natural compound that can mimic the activity of EGF is highly desired in both medical and cosmetic fields. Here, using the modified biosensor system, we observed that natural small-compound isoprocurcumenol, which is a terpenoid molecule derived from turmeric, can activate EGFR signaling. It increased the phosphorylation of ERK and AKT, and upregulated the expression of genes related to cell growth and proliferation, such as c-myc, c-jun, c-fos, and egr-1. In addition, isoprocurcumenol induced the proliferation of keratinocytes in both physical and UVB-induced cellular damage, indicative of its function in skin regeneration. These findings reveal that EGF-like isoprocurcumenol promotes the proliferation of keratinocytes and further suggest its potential as an ingredient for medical and cosmetics use.