排序方式: 共有37条查询结果,搜索用时 15 毫秒
21.
ZSM‐5 coatings, have been synthesized onto a monolithic cordierite substrate by an environmental friendly and high coating selectivity method—Vapor Phase Transport (VPT). With this method, an aluminosilicate gel coated onto the monolithic cordierite substrate has been transformed into a ZSM‐5 layer under vapors of n‐butylamine and water, n‐Butylamine played a key role in the forming of ZSM‐5 layer on the cordierite substrate. The ZSM‐5/cordierite monolith composites prepared by this method were ion‐exchanged with Cu2+ and tested for the selective catalytic reduction of NO by propane. The deNOx activities of Cu/ZSM‐5 monolith catalysts were not only dependent on the ion‐exchange methods, but also on the ZSM‐5 loading of the monolith catalysts. The best result was obtained over the Cu (B3)/ZSM‐5 monolith catalyst, which had a ZSM‐5 loading of about 13% and was prepared by a pressure exchange procedure. At a temperature of 723 K and a space velocity of 10,000 h?1 (based on the monolith volume), 85% of NO conversion and 93% of C3H3 conversion were achieved over the Cu(B3)/ZSM‐5 monolith catalyst. 相似文献
22.
采用第一性原理,研究三方及六方相FAPbI3(FA=HC(NH2)2+)钙钛矿的结构及光电特性.结果表明,FAPbI3钙钛矿由三方到六方的形变能够扭转PbI3骨架,改变Pb-I键合特性,进而改变其禁带宽度值.两种晶体均属于直接带隙半导体,三方相FAPbI3的直接带隙点位于布里渊区Z(0,0,0.5)对称点,具有较为理想的约1.50 eV的禁带宽度;六方相FAPbI3的直接带隙点位于Γ(0,0,0)对称点,具有约2.50 eV的禁带宽度.FA离子不直接参与电子跃迁过程,仅仅充当电荷供体为PbI3骨架提供超过0.7 e的电荷.相比于六方相晶体,三方相FAPbI3具有更小的载流子有效质量,吸收光谱发生了显著的红移,并且其吸收特性优于六方相FAPbI3和四方相MAPbI3(MA=CH3NH3+)钙钛矿.六方相FAPbI3比三方相晶系更稳定,FA和PbI3骨架之间的结合作用力强于MA和PbI3骨架之间的作用力. 相似文献
23.
We investigate the detailed, empirical analysis of the statistical properties of the Railway Network of China (RNC) in space L and space G, constructed by geographic coarse graining process. The RNC exhibits similar properties in the cumulative distributions of degree and strength in two spaces, and it presents the hierarchical structure, small-world behavior and assortativity, areciprocal connection both in space L and space G. We also investigate the path length that every train runs, the distribution of the railroad length per degree and the optimal distribution of stations. 相似文献
24.
无线智能小车不仅在侦查、防爆、防辐射等特殊危险环境中应用广泛,在玩具行业也有很大的应用前景。安卓智能终端在全球拥有很大的市场占有率,通过对安卓手机的重力感应器、蓝牙和小车蓝牙模块HC06、电机驱动模块L298N、单片机等硬件平台进行详细设计和分析,实现了一种新型无线控制智能小车的方法,与传统的遥控器相比,设计的软硬件更为方便和灵活,软件经过不同手机测试,功能和界面都具有良好的适用性和可靠性,体验感也较强,达到了预定目标。 相似文献
25.
26.
We consider fertile hard-core (HC) models with three states on a homogeneous Cayley tree. It is known that four types of such
models exist. For these models, we describe the translation-invariant and periodic HC Gibbs measures. We also construct a
uncountable set of nonperiodic Gibbs measures.
__________
Translated from Teoreticheskaya i Matematicheskaya Fizika, Vol. 156, No. 3, pp. 412–424, September, 2008. 相似文献
27.
用高真空重量吸附、~(29)SiMAS NMR、NH_3-TPD、P_y-IR和正庚烷裂解等方法研究稀盐酸萃取REUSY样品后,对该沸石的孔和骨架结构、酸性和催化裂化功能的影响。吸附及~(29)SiMASNMR的测定结果表明,稀盐酸可以萃取出一部分填充在沸石二次孔中的非骨架铝(EFAl)碎片。NH_3-TPD和P_y-IR的试验结果表明,稀盐酸萃取后,该沸石强、弱酸中心的强度和数目均有所增加。正康烷裂解反应的数据指出,REUSYEX的裂解活性和抗氮性能均较其母体REUSY为高。 相似文献
28.
Yi-hong Ding Ze-sheng Li Yu-guo Tao Xu-ri Huang Chia-chung Sun 《Theoretical chemistry accounts》2002,107(5):253-265
The structures and isomerization pathways of various HC2P isomers in both singlet and triplet states are investigated at the B3LYP/6-311G(d,p), QCISD/6-311G(d,p) (for isomers only)
and single-point CCSD(T)/6-311G(d,p)//B3LYP/6-311G(d,p) levels. At the CCSD(T)/6-311G(d,p)//B3LYP/6-311G(d,p) level, the lowest-lying
isomer is a linear HCCP structure
3
1 in the 3∑− state. The second low-lying isomer has a CPC ring with exocyclic CH bonding
1
5 in a singlet state at 10.5 kcal/mol. The following third and fourth low-lying isomers are a singlet bent HCCP structure
1
1 at 20.9 kcal/mol and a bent singlet HPCC structure
1
3 at 35.8 kcal/mol, respectively. Investigation of the HC2P potential-energy surface indicates that in addition to the experimentally known isomer
3
1, the other isomers
1
1,
1
3 and
1
5 also have considerable kinetic stability and may thus be observable. However, the singlet and triplet bent isomers HCPC
1
2 and
3
2 as well as the triplet bent isomer HPCC
3
3 are not only high-lying but are also kinetically unstable, in sharp contrast to the situation of the analogous HCNC and HNCC
species that are both kinetically stable and that have been observed experimentally. Furthermore, the reactivity of various
HC2P isomers towards oxygen atoms is briefly discussed. The results presented here may be useful for future identification of
the completely unknown yet kinetically stable HC2P isomers
1
1,
1
3 and
1
5 either in the laboratory or in interstellar space.
Received: 5 November 2000 / Accepted: 25 November 2001 / Published online: 8 April 2002 相似文献
29.
FT-IR spectra of mixtures of HC1 and various proton acceptors have been recorded in the gas phase and the enhancement gradient of theP(1) HC1 band with pressure of added gas measured. Bands arising from other collisions to form complexes with longer lifetimes were also measured in the gas and matrix phases. The two kinds of interactions are correlated with proton affinity and dipole moment of added gas. 相似文献
30.