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41.
Chengxin Wang Hinyiu Anthony Chung Matthias Seyboth Markus Kamp Karl Joachim Ebeling Rainer Beccard Michael Heuken 《Journal of Crystal Growth》2001,230(3-4):377-380
Using hydride vapor phase epitaxy the influence of growth parameters on the crack density is studied for thick epitaxially lateral overgrown (ELOG) GaN layers. Reactor pressure, growth rate, and substrate temperature are key factors to obtain crack-free thick GaN layers. The cracking mechanism is discussed and void formation on top of the SiO2 stripes is proposed to play a key role in stress relaxation and crack suppression. 相似文献
42.
对凝结水处理用离子交换树脂的有机溶出物的研究 总被引:2,自引:0,他引:2
对具有代表性的凝结水处理阳、阴各十种离子交换树脂有机溶出物的量及溶出规律进行了测定,同时就阳树脂溶出物对阴离子交换树脂的污染,以及通过再生、碱性盐水复苏对此污染的去除,也作了试验测定。 相似文献
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An indefinite stochastic linear-quadratic (LQ) optimal control problem with cross term over an infinite time horizon is studied, allowing the weighting matrices to be indefinite. A systematic approach to the problem based on semidefinite programming (SDP) and related duality analysis is developed. Several implication relations among the SDP complementary duality, the existence of the solution to the generalized Riccati equation and the optimality of LQ problem are discussed. Based on these relations, a numerical procedure that provides a thorough treatment of the LQ problem via primal-dual SDP is given: it identifies a stabilizing optimal feedback control or determines the problem has no optimal solution. An example is provided to illustrate the results obtained. 相似文献
46.
We report a joint experimental and theoretical study on high pressure structures of nanoporous mayenite (12CaO·7Al(2)O(3)). A pressure-induced amorphization was identified at ~13 GPa by in situ high pressure x-ray experiments. The amorphous product can be decompressed to ambient conditions. Ab initio calculations reveal that the anisotropic deformations of empty cages break the crystallographic long-range orders, leading to the formation of high-pressure amorphous state. Furthermore, the deformation routes of empty cages are found fully dependent on their individual locally structural geometry relevant to the distribution of extra-framework oxygen ions. 相似文献
47.
A stochastic optimal LQR control problem under some integral quadratic (IQ) constraints is studied, with cross terms in both the cost and the constraint functionals, allowing all the control weighting matrices being indefinite. Sufficient conditions for the well-posedness of this problem are given. When these conditions are satisfied, the optimal control is explicitly derived via dual theory. 相似文献
48.
电解液浓度对氢化物电极性能的影响 总被引:1,自引:1,他引:1
镍/氢化物(Ni/MH)电池以其洁净、安全、高容量、大功率、长寿命而受到人们的极大关注。贮氢电极材料的研究是开发Ni/MH电池的中心,已有较多报道。Boonstra等研究了氧化、粉末的处理等对LaNi_5电极性能的影响。本文探讨电解液浓度对MLNi_(3.5)MnCO_(0.4)Al_(0.1)(ML代表富镧混合稀土)电极放电性能的影响,并对其循环伏安性能进行了研究。 贮氢合金是在氩气保护下,将计量比的各组成元素ML、Ni、Mn、Co、Al混合物在高频感应 相似文献
49.
在稀土镍合金贮氢电极(MH)的研究中,曾报道电解液浓度对MLNia_(3.5)MnCo_(0.4)Al_(0.1)(ML代表富镧混合稀土)电极放电性能的影响。本文报道Al含量对MLNi_(4-x)MnAl_x电极性能的影响,并用循环伏安法对电极反应机理进行了探讨。实验方法同前报。 结果与讨论 MLNi_(4-x)MnAl_x电极性能测试 用100mA/S恒电流将MLNi_(4-x)MnAl_x电极充电至300mAh/g,停充10分钟,再用100mA/g恒电流放电至—0.60V(vs Hg/HgO),得如图1的放电曲线。可见随 相似文献
50.
Zhicheng Zhang Yuting Zhang Junmin Li Chengxin Fu Xin Zhang 《Molecules (Basel, Switzerland)》2021,26(12)
Tea polyphenols (TPs) are the general compounds of natural polyhydroxyphenols extracted in tea. Although a large number of studies have shown that TPs have obvious neuroprotective and neuro repair effects, they are limited due to the low bioavailability in vivo. However, TPs can act indirectly on the central nervous system by affecting the “microflora–gut–brain axis”, in which the microbiota and its composition represent a factor that determines brain health. Bidirectional communication between the intestinal microflora and the brain (microbe–gut–brain axis) occurs through a variety of pathways, including the vagus nerve, immune system, neuroendocrine pathways, and bacteria-derived metabolites. This axis has been shown to influence neurotransmission and behavior, which is usually associated with neuropsychiatric disorders. In this review, we discuss that TPs and their metabolites may provide benefits by restoring the imbalance of intestinal microbiota and that TPs are metabolized by intestinal flora, to provide a new idea for TPs to play a neuroprotective role by regulating intestinal flora. 相似文献