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21.
A well-resolved uudd cyclic water tetramer was reported in the crystal host of [Cu(adipate)(4,4-bipyridine)].(H(2)O)(2), showing the contribution of the water cluster to the stability of the crystal host and the role of cooperative association of the water cluster and the crystal host in the formation of the water cluster. 相似文献
22.
Investigation of passivation effects in AlGaN/GaN metal-insulator-semiconductor high electron-mobility transistor by gate-drain conductance dispersion study 下载免费PDF全文
This paper studies the drain current collapse of AlGaN/GaN metal-insulator-semiconductor high electron-mobility transistors (MIS-HEMTs) with NbAlO dielectric by applying dual-pulsed stress to the gate and drain of the device.For NbAlO MIS-HEMT,smaller current collapse is found,especially when the gate static voltage is 8 V.Through a thorough study of the gate-drain conductance dispersion,it is found that the growth of NbAlO can reduce the trap density of the AlGaN surface.Therefore,fewer traps can be filled by gate electrons,and hence the depletion effect in the channel is suppressed effectively.It is proved that the NbAlO gate dielectric can not only decrease gate leakage current but also passivate the AlGaN surface effectively,and weaken the current collapse effect accordingly. 相似文献
23.
24.
Comparison of hot-hole injections in ultrashort channel LDD nMOSFETs with ultrathin oxide under an alternating stress 下载免费PDF全文
The behaviours of three types of hot-hole injections in ultrashort
channel lightly doped drain (LDD) nMOSFETs with ultrathin oxide
under an alternating stress have been compared. The three types of
hot-hole injections, i.e. low gate voltage hot hole injection
(LGVHHI), gate-induced drain leakage induced hot-hole injection
(GIDLIHHI) and substrate hot-hole injection (SHHI), have different
influences on the devices damaged already by the previous hot
electron injection (HEI) because of the different locations of
trapping holes and interface states induced by the three types of
injections, i.e. three types of stresses. Experimental results show
that GIDLIHHI and LGVHHI cannot recover the degradation of electron
trapping, but SHHI can. Although SHHI can recover the device's
performance, the recovery is slight and reaches saturation quickly,
which is suggested here to be attributed to the fact that trapped
holes are too few and the equilibrium is reached between the
trapping and releasing of holes which can be set up quickly in the
ultrathin oxide. 相似文献
25.
Liu Jing-Hui Tian Jin-Rong Hu Meng-Ting Xu Run-Qin Dou Zhi-Yuan Yu Zhen-Hua Song Yan-Rong 《中国物理 B》2015,24(2):24215-024215
We present a passively Q-switched Yb:KGW laser based on a transmission-type saturable absorber of topological insulator:Bi_2Se_3.The saturable absorber is prepared on a 0.17-mm glass substrate and can translate intra-cavity for best performance nearly without influence on the laser mode.At a maximum pump power of 13.7 W,the central wavelength,pulse duration,repetition rate,and pulse energy of Q-switched pulse are 1043 nm,1.5 μs,175.4 kHz,6.39 μJ,respectively.The maximum output power is 1.12 W.To our knowledge,this is the highest average output power from passively Qswitched lasers with topological insulator saturable absorbers. 相似文献
26.
CuO/Sn0.8Ti0.2O2催化剂的表征及对NO+CO反应活性研究 总被引:2,自引:0,他引:2
Reducibility and characteristics of CuO/Sn0.8Ti0.2O2 catalysts were examined by using a microreactor-GC NO+CO reaction system, BET, TG-DTA, FTIR, XRD and H2-TPR techniques.
CuO/Sn0.8Ti0.2O2 had high activity in NO+CO reaction, showing 93% NO conversion at 300 ℃ in air, and 100% NO conversion at 225 ℃ after
H2 pretreatment. The pore size distribution of Sn0.8Ti0.2O2
was mainly as micro-pores and meso-pores (1~5 nm), and the specific surface area and total pore volume of
Sn0.8Ti0.2O2 were 69 m2·g-1 and 0.15
cm3·g-1, respectively. As shown by XRD analysis, there was no CuO crystal diffraction peak at 9%CuO loading, but two CuO crystal diffraction peaks at 2θ 35.5° and 38.7° were present at 12% CuO loading. FTIR detected the adsorption of NO and CO on the surface of reduced
12%CuO/Sn0.8Ti0.2O2. The Cu2+ sites and support surface adsorbed NO, and the process of NO adsorption led to the formation of
N2O and NO3-. In contrast, the Cu+、Cu0 sites and support surface adsorbed CO, and when the mixed gases of NO and CO were adsorbed by support surface, no
NO3- was formed. H2-TPR showed four reduction peaks (α, β, γ and δ). The α, β and γ peaks were the reductions of CuO species, and the δ peak was the reduction of
Sn0.8Ti0.2O2. 相似文献
27.
Zhang Qi Zhai Jian-Jun Zhang Yan-Rong Liu Ying-Mei Wang Liu-Fang Li Shu-Ben Liao Dai-Zheng Wang Geng-Lin 《Transition Metal Chemistry》2000,25(1):93-98
Six transition metal(II) complexes with 8-acetyl-4-methyl umbelliferone (AMUH), ML2 (L=AMU–; M=Mn, Co, Ni, Cu, Zn and Cd), have been synthesized and characterized by elemental analysis, electrical conductance, i.r., 1H-n.m.r. and u.v. spectroscopic techniques. The e.s.r. spectra show that CuL2 is anisotropic, with g2.05 and g2.26. The MnL2 species is characterized by a very broad g2 centered resonance without manganese hyperfine structure. The antioxidative and other biological activities of selected complexes were also investigated, indicating that both the ligand and complexes exhibit a scavenging effect on the superoxide radical (O2
–·) and a suppressing effect on the hydroxyl radical (·OH). The suppressing effect on ·OH is greater than the scavenging effect on O2
–·. The Cu and Mn complexes exhibit very significant suppression ratios for both radicals. However, the inhibitory effect on lipid peroxides results show that, in the initial stage, the Cu and Mn complexes exhibit obvious inhibitory effects on lipid peroxides, but after one hour, they begin to accelerate the lipid peroxides. Lower catalytic activity and instability when the complexes react with active oxygen may be responsible for this dual nature. The ligand and four transition metal(II) complexes selectively, obviously, inhibit the growth of HCT-8 and HL-60 tumour cell lines. They also exhibit a minor influence on the proliferation of B cells in higher concentration (10–5m), but only a weak effect on the proliferation of T cells of the BALB/C (nude rate) spleen cells. 相似文献
28.
制备了一系列通过苯氧基修饰的聚(苯乙烯-异丙烯膦酸)磷酸氢锆(ZPS-IPPA)轴向固载手性MnⅢ(Salen)催化剂,并将其应用于苯乙烯的环氧化反应。催化结果表明:苯氧链接手臂邻位取代基对于环氧化结果有重要影响,相比邻位取代基为-H和-CH3,取代基为t-Bu基团时,催化剂能够提供更高水平的对映选择性。同时,比较了两种长度几乎一致的链接手臂(-NH-C6H4-NH-,-O-C6H4-O-),结果表明:在没有轴向助剂N-甲基玛琳氮氧化物(NMO)参与下,在间氯过氧苯甲酸(m-CPBA)为氧化剂的体系中, 链接手臂-O-C6H4-O-比-NH-C6H4-NH-更有利于取得优异的催化效果。制备的非均相催化剂在前5次后催化活性与对映选择性几乎没有明显的变化。 相似文献
29.
用经典辐射理论对线偏振周期量级激光脉冲的线性Thomson散射进行分析,从理论上得到它可产生亚阿秒脉冲的结论. 计算显示,在电子相对论因子为50、激光脉冲中心波长为1μm、归一化光场强度为0.01的情况下,用包含1.5个光周期的激光脉冲,可获得0.2as(半高全宽)的散射脉冲输出. 还对光场载波包络初相φce和电子进入光场的初相φin对散射脉冲的影响作了分析讨论,结果表明,在适当的φce和φin条件下,能实现单个阿秒脉冲输出,并可对脉冲宽度和频率进行调谐.
关键词:
线性Thomson散射
周期量级激光脉冲
载波包络初相
阿秒脉冲 相似文献
30.
在激光分子束外延实验中,用RHEED原位监测了SrTiO3基片初始、退火以及同质外延过程中的表面形态.通过对RHEED图案分析,获取了表面面内的晶格常数振荡与衍射条纹的半高宽振荡现象,前者是由退火重构表面与薄膜之间的界面造成的,后者与二维岛边界的弛豫相关.另外还观察到了等离子体对入射电子束的影响而导致的RHEED强度振荡行为的相位移现象.
关键词:
反射高能电子衍射
SrTiO3
表面晶格常数及衍射强度振荡 相似文献