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排序方式: 共有929条查询结果,搜索用时 15 毫秒
71.
Chih‐Wei Hsu Abhijit Ganguly Chi‐Hui Liang Yu‐Ting Hung Chien‐Ting Wu Geng‐Ming Hsu Yang‐Fang Chen Chia‐Chun Chen Kuei‐Hsien Chen Li‐Chyong Chen 《Advanced functional materials》2008,18(6):938-942
We report the structure and emission properties of ternary (In,Ga)N nanowires (NWs) embedded with self‐assembled quantum dots (SAQDs). InGaN NWs are fabricated by the reaction of In, Ga and NH3 via a vapor–liquid–solid (VLS) mechanism, using Au as the catalyst. By simply varying the growth temperature, In‐rich or Ga‐rich ternary NWs have been produced. X‐ray diffraction, Raman studies and transmission electron microscopy reveal a phase‐separated microstructure wherein the isovalent heteroatoms are self‐aggregated, forming SAQDs embedded in NWs. The SAQDs are observed to dominate the emission behavior of both In‐rich and Ga‐rich NWs. Temperature‐dependent photoluminescence (PL) measurements indicate relaxation of excited electrons from the matrix of the Ga‐rich NWs to their embedded SAQDs. A multi‐level band schema is proposed for the case of In‐rich NWs, which showed an anomalous enhancement in the PL peak intensity with increasing temperature accompanies with red shift in its peak position. 相似文献
72.
Shiang Suo Huang Lan Hui Chih Chia Hsien Lin Long Y. Chiang Tadahiko Mashino Masataka Mochizuki Kensuke Okuda Takasi Hirota Ming-Cheng Tsai Ming Cheng Tsai 《Fullerenes, Nanotubes and Carbon Nanostructures》2001,9(3):375-395
The effects of hexasulfobutylated (FC4S), the fullerene derivative on the contraction of smooth muscle were tested pharmacologically on the circular muscle of stomach of guinea pigs. The effects of monomalonic acid C60 (MMA C60) on the same preparations were compared. The effects of those compounds on the taenia coli, portal vein and vas deferens of guinea pigs were also tested. The FC4S did, while MMA C60 did not elicit contracture of the circular muscle of stomach and taenia coli. Both FC4S and MMA C60 did not elicit contraction on the portal vein and on the vas deferens of the guinea pig. Prazosin (0.5 μM) or propranolol (0.5 μM) did not alter the FC4S elicit contracture of the circular muscle of stomach. However, atropine (0.01, 0.1 and 1 μM), tetrodotoxin (0.1 μM) or low calcium medium decreased reversibly the FC4S elicited contracture of the circular muscle of stomach. The effect of FC4S on the contracture of the gastric muscles was also tested using various muscarinic receptor subtype antagonists. 4-DAMP (1 μM), muscarinic M3 receptor antagonist, and tropicamide (1 μM), muscarinic M4 receptor antagonist, did not alter the contracture elicited by FC4S. Pirenzepine (0.1 μM), muscarinic M1 receptor antagonist, and methoctramine (0.25 μM), muscarinic M2 receptor antagonist, significantly decreased the FC4S elicited contracture of the circular muscle. Atropine (1 μM) or tetrodotoxin (0.1 μM) completely blocked the FC4S elicited contracture of the circular muscle of stomach. It is concluded that FC4S elicited contracture of the circular muscle of stomach. The effect may be due to FC4S acts on the cholinergic cells existed in the gastric muscle and indirectly activating the tetrodotoxin dependent releasing of the transmitters from the cells, then, activating the muscarinice M1, M2 receptors in the muscle eliciting the contractures. 相似文献
73.
C.Y. Chia 《Composite Structures》1985,4(2):161-178
This paper is analytically concerned with nonlinear flexural oscillation of an unsymmetrically laminated angle-ply rectangular plate resting on a Pasternak-type elastic foundation. The plate edges are subjected to the varying rotational constraints. Based on dynamic von Kármán-type nonlinear plate theory a single-mode analysis is carried out. In the formulation of a solution the force function and bending moments along the four edges are expanded into generalized Fourier series. These moments are also replaced by an equivalent lateral pressure near these edges. Galerkin's procedure and the perturbation technique are applied to the equation of motion and the time equation respectively. Numerical results for the amplitude-frequency response of the plate are presented graphically for various high-modulus composite materials, geometries of lamination, aspect ratios, moduli of elastic foundation and boundary conditions. Present results are compared with the existing values. 相似文献
74.
The main investigation presented in this work is focused on the design and fabrication of redistribution in wafer level chip scale package (RDL in WLCSP) for high power device application. The design considers higher carrier loading incorporated with the dimensional broadening in both lateral and thickness direction of the metal redistribution layer. The lateral broadening shortens the channels of electrical isolation, while the thickness broadening evolves the conventional sputtering into the present electro-plating achieved Cu metallization layer. The innovation brings about the challenge for high power RDL in WLCSP. In this study, the interplay between structural design, process interactions, and possible solutions for high power RDL in WLCSP are presented. To address the arguments, two designs of experiment are conducted. We demonstrate the determinative influence factors, resultant from process interactions, toward the adhesive properties beyond the conventional wisdom. 相似文献
75.
Tsang‐Ling Sheu Chia‐Nan Lin Jenq‐Neng Hwang 《Wireless Communications and Mobile Computing》2015,15(12):1589-1605
This paper presents a channel reservation and preemption (CRP) model using overlapping regions in a cellular network with multiple sectors. To fully exploit and reuse the frequencies, directional antennas are installed on base stations (BSs) to divide the coverage into a number of equal‐sized sectors. When traffic is unevenly distributed across the sectors in a BS, channel utilization in every sector may become very different; low‐traffic sectors may be underutilized while high‐traffic sectors may be overutilized. A CRP scheme is thus proposed to more efficiently utilize free channels among sectors. CRP aims at reducing the dropping probabilities of handoff calls. Specifically, when free channels in a sector are not available, a handoff call, instead of being dropped, is allowed to preempt an ongoing call residing in the overlapping region of two adjacent sectors or two neighbor cells. Under CRP, the preempted ongoing call will not be disconnected, because it can switch over its service to the BS of a neighbor cell or to another directional antenna of an adjacent sector. For the purpose of evaluation, we build an analytical model for the proposed CRP using six‐tuple Markov chains. Analytical results show that the proposed CRP can significantly reduce the dropping probabilities of inter‐sector handoff calls, particularly when traffic between two sectors is not evenly distributed. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
76.
High cost of renewable energy systems has led to its slow adoption in many countries. Hence, it is vital to select an appropriate size of the system in order to reduce the cost and excess energy produced as well as to maximize the available resources. The sizing of hybrid system must satisfy the LPSP (Loss of Power Supply Probability) which determines the ability of the system to meet the load requirements. Once the lowest configurations are determined, the cost of the system must then be taken into consideration to determine the system with the lowest cost. The optimization methodology proposed in this paper uses the ANFIS (Adaptive Neuro-Fuzzy Inference System) to model the PV and wind sources. The algorithm developed is compared to HOMER (Hybrid Optimization Model for Electric Renewables) and HOGA (Hybrid Optimization by Genetic Algorithms) software and the results demonstrate an accuracy of 96% for PV and wind. The optimized system is simulated in PSCAD/EMTDC and the results show that low excess energy is achieved. The optimized system is also able to supply power to the load without any renewable sources for a longer period, while conforming to the desired LPSP. 相似文献
77.
J Thumboo SN Tham YK Tay T Chee B Mow HP Chia ML Boey 《Canadian Metallurgical Quarterly》1997,24(10):1949-1953
OBJECTIVE: To determine the clinical features of psoriatic arthritis (PsA) in a multiethnic Oriental population and to study the effect of ethnicity on disease patterns. METHODS: A retrospective study of 80 patients with PsA seen at either a rheumatology or dermatology referral center. Patients and case records were reviewed and data abstracted according to a standard protocol. Eighty consecutive patients with psoriasis without PsA seen at the dermatology center were recruited as controls. RESULTS: Asymmetric polyarthritis developing in the 4th decade with an equal male to female ratio was the commonest pattern of arthritis among Chinese, Indians, and Malays. Clinically apparent lumbar spondylitis was significantly more common in Indians than Chinese (10/11 vs 11/20, respectively; p = 0.046), although the prevalence of lumbar spondylitis was similar in all ethnic groups. Eighty-nine percent of subjects required nonsteroidal antiinflammatory drugs and 51% required disease modifying antirheumatic drugs at some time for control of joint disease. PsA was significantly more common among Indians compared to the ethnic distribution of the Singapore population (p < 0.000001). Multiple logistic regression identified Indian ethnicity as a risk factor for the development of PsA (OR 2.39, 95% confidence interval 1.02 to 5.60). CONCLUSION: The commonest pattern of PsA in all ethnic groups was asymmetric polyarthritis. Ethnicity affected the development and presentation of PsA in our series: Indians with psoriasis had double the risk of developing PsA compared to Chinese with psoriasis, and lumbar spondylitis when present in Chinese subjects was asymptomatic in 45%, being detectable only on radiological examination. 相似文献
78.
Jun‐Qiang Huang Cho‐Chun Hu Tai‐Chia Chiu 《International journal of cosmetic science》2013,35(4):346-353
A micellar electrokinetic chromatography method using cetyltrimethylammonium bromide (CTAB) as a cationic surfactant, coupled with UV–Vis detection, was developed for the simultaneous determination of seven preservatives, including methyl‐, ethyl‐, propyl‐ and butyl‐paraben and phenol, phenoxyethanol and resorcinol. The method involved optimizing the pH of the phosphate buffer and concentrations of CTAB, ethanol and 2‐hydroxypropyl‐β‐cyclodextrin (HP‐β‐CD). The preservatives were well separated using optimum conditions and separated within 10 min at a separation voltage of ?12.5 kV with the 1.0 mM phosphate buffer (pH 7.0) containing 90 mM CTAB, 25 mM HP‐β‐CD and 10% (v/v) ethanol. Satisfactory recoveries (84.1–103.0%), migration time (RSD < 3.1%) and peak area (RSD < 4.5%) repeatabilities were achieved. Detection limits of the preservatives were between 0.31 and 1.52 μg mL?1 (S/N = 3, n = 5). The optimized method was successfully applied to the simultaneous determination of these preservatives in 10 commercial cosmetic products. 相似文献
79.
Mengjiao Li Feng-Shou Yang Hung-Chang Hsu Wan-Hsin Chen Chia Nung Kuo Jiann-Yeu Chen Shao-Heng Yang Ting-Hsun Yang Che-Yi Lin Yi Chou Mu-Pai Lee Yuan-Ming Chang Yung-Cheng Yang Ko-Chun Lee Yi-Chia Chou Chen-Hsin Lien Chun-Liang Lin Ya-Ping Chiu Chin Shan Lue Shu-Ping Lin Yen-Fu Lin 《Advanced functional materials》2021,31(5):2007587
Defect engineering represents a significant approach for atomically thick 2D semiconductor material development to explore the unique material properties and functions. Doping-induced conversion of conductive polarity is particularly beneficial for optimizing the integration of layered electronics. Here, controllable doping behavior in palladium diselenide (PdSe2) transistor is demonstrated by manipulating its adatom-vacancy groups. The underlying mechanisms, which originate from reversible adsorption/desorption of oxygen clusters near selenide vacancy defects, are investigated systematically via their dynamic charge transfer characteristics and scanning tunneling microscope analysis. The modulated doping effect allows the PdSe2 transistor to emulate the essential characteristics of photo nociceptor on a device level, including firing signal threshold and sensitization. Interestingly, electrostatic gating, acting as a neuromodulator, can regulate the adaptive modes in nociceptor to improve its adaptability and perceptibility to handle different danger levels. An integrated artificial nociceptor array is also designed to execute unique image processing functions, which suggests a new perspective for extension of the promise of defect engineered 2D electronics in simplified sensory systems toward use in advanced humanoid robots and artificial visual sensors. 相似文献
80.