Sushil R. Kanel
,
Heath Misak
,
Dhriti Nepal
,
Shankar Mall
,
Seth W. Brittle
,
Ioana Sizemore
,
David M. Kempisty
,
Mark N. Goltz
新型炭材料
doi:10.1016/S1872-5805(16)60021-5
碳纳米管纱( CNTY)因具有优异的力学强度、化学稳定性、热稳定性和高比表面积而成为去除废水中有机污染物的潜在材料。本文将CNTY用于含2,4-二硝基甲苯(DNT)的污水处理。 CNTY对DNT的吸附能力与文献报道值作对比研究,同时探讨吸附动力学。采用SEM-EDX、HRTEM、Raman与XPS表征CNTY吸附DNT前后的尺寸、表面形貌及表面化学。结果表明,经CNTY对DNT污水处理后的水质达到实验室无离子水级纯度。 CNTY对DNT吸附符合Freundlich吸附等温线, Freundlich参数由KF 为55.0 mg/g (L/mg)1/n,指数1/n为0.737得到,表明其比活性炭吸附性弱,但更易再生。 CNTY比活性炭的吸附性速率更快,遵循拟二级动力学模型。 CNTY吸附DNT引起D、G常偏移,归因于CNTs与DNT间电子受体和供体效应。
关键词:
碳纳米管纱
,
2,4-二硝基甲苯
,
吸附
,
Freundlich吸附等温线
,
新兴技术
方雪
,
苏桂明
,
姜海健
,
陈明月
,
马宇良
,
姚立明
,
张晓臣
,
张伟君
高分子材料科学与工程
通过对5组相同结构不同相对分子质量的由二氨基二苯醚(ODA)和均苯四甲酸二酐(PMDA)在N,N-二甲基乙酰胺(DMAc)体系中聚合而成的均苯型聚酰胺酸——PAA(ODA/PMDA),进行凝胶渗透色谱和特性黏度[η]的测定实验,测定了5组PAA(ODA/PMDA)的Mn和-Mw,并计算其相对分子质量分布:d1 =2.18,d2 =2.37,d3=1.97,d4=2.33,d5=2.42;室温下测定了PAA(ODA/PMDA)在DMAc中的Mark-Houwink方程参数,从而得到DMAc体系均苯型PAA(ODA/PMDA)的Mark-Houwink方程参数K1 =2.34× 10-5,α1=0.6867,K2=1.98×10-7,α2 =0.9691.
关键词:
凝胶渗透色谱
,
聚酰胺酸
,
Mark-Houwink方程参数
赫荣安
,
胡伟娜
,
李效东
,
斯永敏
,
楚增勇
高分子材料科学与工程
通过沉淀分级和凝胶色谱(GPC)分级制备了窄分布的聚碳硅烷(PCS),并用多角度激光光散射(MALLS)和GPC分别测定其绝对分子量和分子量分布.采用试差拟合的方法定制了PCS的标定曲线,并用该标定由线和普适标定方程,确定了25℃时,PCS在在四氢呋喃(THF)中的Mark-Houwink常数(K=6.8×10-4mL/g,α=0.855).经验证,PCS与聚幕乙烯(PS)在THF中符合瞢适标定关系.
关键词:
聚碳硅烷
,
Mark-Houwink常数
,
分子量分布
刘伟
,
李伯耿
,
沈炯
,
潘祖仁
高分子材料科学与工程
通过对不同分子量的间规聚苯乙烯(sPS)的凝胶渗透色谱(GPC)和特性粘度[η]的测定,应用普适校正原理和参数优化的方法,订定了135 ℃时,sPS在邻二氯苯(ODCB)中的Mark-Houwink方程参数,即:K＝1.11×10-4(100 mL/g),α＝0.72.利用K、α值计算了sPS的粘均分子量η和溶度参数δsPS.
关键词:
间规聚苯乙烯
,
Mark-Houwink参数
,
特性粘度
,
溶度参数:分形维数
Molecular Physics
The ab initio method based on density functional theory at the B3PW91 level has been applied to study the geometric, electronic, and magnetic properties of neutral and anionic Au(n)Pd (n = 1-9) clusters. The results show that the most stable geometric structures adopt a three-dimensional structure for neutral Au(7)Pd and Au(8)Pd clusters, but for anionic clusters, no three-dimensional lowest-energy structures were obtained. The relative stabilities of neutral and anionic Au(n)Pd clusters were analysed by means of the dependent relationships between the binding energies per atom, the dissociation energies, the second-order difference of energies, the HOMO-LUMO energy gaps and the cluster size n, and a local odd-even alternation phenomenon was found. Natural population analysis indicates the sequential transfer from the Pd atom to the Au(n) frame in Au(1,2,3,5)Pd and Au(2,3)Pd(-) clusters, and from the Au(n) frame to the Pd atom in other clusters. Much to our surprise, irrespective of whether it is the total magnetic moment or the local magnetic moment, the magnetic moment presents an odd-even alternation phenomenon as a function of the cluster size n. The magnetic effects are mainly localized on the various atoms (Au or Pd) for different cluster size n.
关键词:
neutral and anionic Au(n)Pd clusters;geometrical configuration;density;function method;generalized gradient approximation;photoelectron-spectroscopy;palladium clusters;gold nanoclusters;metal-clusters;exchange;nanoparticles;molecules;chemistry;au-n(-)
Surface & Coatings Technology
Ti-B-N coatings were deposited on W18Cr4V high speed steels by using EB-ion plating with different boron contents. The chemical compositions of the coating are Ti, B and N. It was found that Ti, B and N in the coating are homogeneous, but there exists a diffusion zone at the coating/substrate interface on the basis of the results of ion probe microanalysis and Auger electron spectrometry. The boron content of the coating is 3-16 at.% given by nuclear reaction analysis. The ratio of nitrogen to titanium of the coating is about 1 given by electron probe microanalysis. The microhardness (HV) of the coating is 35-45 GPa (load of 0.25 N). The critical load of the coating using the scratch test is 12-14 N. The sliding friction coefficient of the coating on diamond stylus is 0.086-0.097 (load of 8.8 N). X-ray diffraction measurement shows that the coating consists of f.c.c. TiN, simple orthorhombic TiB, cubic BN and simple hexagonal Ti-B-N phases. As expected, the higher the boron content, the higher the content of cubic BN and TiB phases; and the higher the microhardness, the lower the adhesion.
关键词:
composition;property;EB-ion plating;Ti-B-N coating;tribological properties;hard coatings;behavior;film;gas
贾素秋
,
于淑敏
,
李军
,
雷军
电镀与涂饰
doi:10.3969/j.issn.1004-227X.2007.06.001
将Si3N4纳米粒子加入电镀镍的基础镀液中,在碳钢上制备了Ni-Si3N4复合镀层.扫描电镜观察表明,复合镀层的表面晶粒细小致密.能谱分析结果表明,镀层表面以Ni元素为主,且含有少量的Si和N.随着镀液中纳米Si3N4粒子含量的增加,镀层的显微硬度升高.热震法和划痕法实验表明,镀层与基体结合良好.
关键词:
Ni-Si3N4复合镀层
,
电沉积
,
形貌
,
显微硬度
Journal of Physical Chemistry C
The Li-Mg-N-H system was prepared by reacting magnesium amide [Mg(NH(2))(2)] with lithium nitride (Li(3)N) and investigated with regard to the hydrogen storage properties. Our study shows that the present method is superior to the conventional route in enhancing the reversible dehydrogenation properties. Through optimizing the Li(3)N:Mg(NH(2))(2) ratio in the starting materials, the reversible capacity of U-Mg-N-H system increases to 4.9 wt %, 18% higher than that typically obtained from the Mg(NH(2))(2) + 2LiH mixture at 200 degrees C. Furthermore, increasing the Li(3)N:Mg(NH(2))(2) ratio is effective for mitigating the ammonia release from thus-prepared samples. Combined property/structure investigations indicate that the obtained enhancements should be ascribed to the effects of LiNH(2) and LiH that were in situ generated from the excess Li(3)N. LiNH(2) may promote the dehydrogenation reaction via seeding the reaction intermediate. The concurrently generated LiH acts as an effective ammonia trapping agent. These findings highlight the potential of "intermediate seeding" as a strategy to enhance the reversible hydrogen storage properties of metal-N-H systems.
关键词:
complex hydrides;ultrafast reaction;amide;improvement;desorption;linh2;destabilization;mechanism;mixtures;imides
吕会敏
,
张钧
材料研究学报
采用多弧离子镀技术和Ti-Al合金靶及Zr单质靶的组合,在高速钢基体上制备了(Ti,Al,Zr)N多元N梯度硬质反应膜.分别用扫描电镜、X射线衍射仪观察测定(Ti,Al,Zr)N梯度膜膜层的表面、断面形貌、成分以及相结构,研究了(Ti,Al,Zr)N多元氮梯度硬质反应膜的组织结构和性能.结果表明,与TiN、(Ti,Al)N、(Ti,Zr)N及(Ti,Al,Zr)N等单层硬质膜相比,采用Ti-Al合金靶及单质Zr靶组合方式制备的(Ti,Al,Zr)N多元氮梯度硬质反应膜具有较高的硬度和膜/基附着力,硬度最高可达HV6000,膜/基附着力大于180 N.同时,膜层还具有良好的抗热震性能.
关键词:
材料表面与界面
,
(Ti,Al,Zr)N膜
,
多弧离子镀
,
显微硬度
,
热震
