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81.
Generally there are four main difficulties in evaluating complex large-scale system reliability, availability and MTBF: the system structure may be very complex; subsystems may follow various failure distributions; subsystems may conform to arbitrary failure and repair distributions for maintained systems; the failure data of subsystems are sometimes not sufficient, reliability test sample sizes tend to be small. It is difficult and often impossible to obtain s-confidence limits of them by classical statistics. Monte Carlo technique combined with Bayes method is a powerful tool to solve this kind of problems. In this survey, the typical existing Monte Carlo reliability, availability and MTBF simulation procedures, variance reduction methods, and random variate generation algorithms are analyzed and summarized. The advantages, drawbacks, accuracy and computer time of Monte Carlo simulation in evaluating reliability, availability and MTBF of a complex network are discussed. Finally, some conclusions are drawn and a general Monte Carlo reliability and MTTF assessment procedure is recommended. 相似文献
82.
Xingwang Fang Roy C. Willis Quoc Hoang Kevin Kelnar Weiwei Xu 《Journal of The Association for Laboratory Automation》2004,9(3):140-145
The demand for high-throughput RNA isolation has been dramatically increasing with wide applications of RNAi, expression profiling, and molecular diagnosis. A comparison of various RNA isolation methods that have been adapted to high-throughput platforms, focusing on consistently high yield and quality of isolated RNA, reduction of cross-contamination, and simplicity and robustness of the protocol is presented. The streamlining of RNA isolation with RNA quantification by qRT-PCR and amplification for microarray analysis is also discussed. In general, a microspheric bead-based approach results in more consistent RNA recovery than glass fiber filter-based RNA isolation method, and RNA can be eluted in a smaller volume. This is because beads can be fully re-suspended in solution to enable more thorough mixing, washing, and elution, whereas the glass fiber matrix is fixed in a filter plate. 相似文献
83.
Taeil Kim Qian Yi Emily Hoang Rahim Esfandyarpour 《Advanced Materials Technologies》2021,6(4):2170022
84.
Donghwan Kim Hoang Tran Thi Thuy Byeonggwan Kim Yanghyun Auh Maxime Rémond Kwang Keat Leong Ting Liang Jinbo Kim Eunkyoung Kim 《Advanced functional materials》2023,33(3):2208157
Synergistically enhancing luminescent and ferroelectric ( SELF ) properties are observed from a tetraphenylethene ( TP ) substituted with clipping groups ( C ), where the C is consisting of a 4-[3,5-bis-(3-decyloxy-styryl)-styryl]-phenyl ( DOS ) unit. The DOS units of TPCn are self-assembled via intermolecular interaction to clip themselves and induce TP aggregation, as evidenced by clip-induced quenching of emission at DOS units ( E clip ) accompanied by aggregation-induced emission enhancement of TPs ( E AIE ). TPC4 demonstrates strong photoluminescence in a dilute chloroform solution and large EAIE in aqueous (>50%) THF solution. TPCn demonstrates SELF properties in film state, with high quantum yields of photoluminescence (>80%) and ferroelectric switching. Due to the introduction of four clips, TPC4 has a higher remnant polarization ( P r = 2.27 µC cm−2) at room temperature than TPC1. TPC4 is successfully employed in a light-emitting electrochemical cell to achieve over 1290 cd m−2 under pulsed current conditions. The TPC4 film on a flexible substrate produced a piezoelectric output voltage of up to 0.13 V and a current density of 1.14 nA cm−2 upon bending. These results indicate that the side chain clipping and TP aggregation resulted in unprecedented flexible SELF properties in a single compound, offering simultaneous enhancement of electroluminescence, mechanical sensitivity, and energy harvesting capacity. 相似文献
85.
Data-driven control has received increasing attention by researchers in recent years because no system modeling procedure is required. By combination of data-driven and model predictive control, this paper discusses an improved model-free adaptive predictive control approach with application to vibration reduction of an elastic crane. For system linearization, instead of using traditional compact-form dynamic linearization, this contribution considers the partial-form dynamic linearization (PFDL) technique in case of multivariable systems. A linearized output predictive model of the unknown system is constructed locally. To estimate and predict the time-varying parameter matrices, namely, pseudo-Jacobian matrix (PJM), recursive least-squares algorithms are utilized for online estimation improvement. As a result, an improved PFDL-based model-free controller is designed and applied firstly to the ship-mounted boom crane representing a typical flexible system. Simulation results indicate that significant reduction of the elastic boom and payload oscillations are achieved, and better control performance can be observed in comparison with other traditional methods. 相似文献
86.
Tan Hoang Vu Nguyen;Mohammad Tauquir Alam Shamim Shaikh;Ho Jung Jeon;Thi Thanh Huong Vu;Chowdam Venkata Prasad;Madani Labed;Sangmo Kim;You Seung Rim; 《Advanced Electronic Materials》2024,10(5):2300759
Biocompatible and biodegradable resistive random-access memory devices using Mg/agarose/Al2O3/Mg-based organic/inorganic structures are reported, showing nonvolatile bipolar resistive switching memory behavior. The organic/inorganic-based hybrid active layer has large working windows (≈106) and is highly stable up to 200 continuous sweeps. The device can be also tuned into multilevel memory by varying the compliance current from a few microamperes to several milliamperes. The formation of metallic filaments inside the active layer during SET and RESET stages using an X-ray photoelectron spectroscopy depth profile and magnesium (Mg) metallic ions that penetrate the agarose layer is confirmed. For the bioresorbable test in both deionized water and phosphate-buffered saline solution, the erasing time of whole devices can be adjusted by using an ultrathin ALD-grown Al2O3 film. 相似文献
87.
Taeil Kim Qian Yi Emily Hoang Rahim Esfandyarpour 《Advanced Materials Technologies》2021,6(4):2001021
Wearable biosensors′ ability to measure continuous health parameters gives promise to healthcare with great potentials to advance precision medicine. The stability and balance within the human body are critical for organ systems′ normal functions. The imbalance of electrolytes may lead to several diseases such as hypertension, heart failure, and kidney diseases. Sweat electrolytes analysis, that is, the analysis of one of the noninvasively accessible biofluids, can provide important information about physiologically relevant quantities, and a combination of them can be employed for comprehensive studies. However, wearable biosensors′ large-scale utilization for extensive population monitoring requires rapid, reliable, low-cost, and high-throughput integration of such platforms. Here, 3D-printing technology is adapted to develop a novel, multiplex, low-cost, and mechanically flexible all-inclusive integrated wearable (AIIW) patch, which contains 3D-printed flexible sensors along with flexible wearable-microfluidic sample handling (WMFSH) units, integrated in a few hours. The AIIW patch is fully characterized, and its utility for noninvasive and continuous health monitoring is successfully demonstrated by simultaneous ex situ and in situ measuring of multiple electrolyte levels in sweat. This work is envisioned as another step toward enabling personalized health monitoring practices by implementing 3D-printing technology in the easy and low-cost development of customized integrated, flexible wearable biosensing platforms to monitor an individual's health parameters. 相似文献
88.
Yongyue Yu;Yang Yang;Minh Tam Hoang;Wei-Hsun Chiu;Le Pang;Anthony P. O’Mullane;Hongxia Wang; 《Solar RRL》2024,8(1):2300732
Carbon electrode-based perovskite solar cells (C-PSCs) exhibit a promising future for commercialization, due to their low cost, facile fabrication, and mass production potential. However, compared with metal-based counter electrodes, carbon electrodes (CEs) often suffer from relatively low electrical conductivity, porous and rough morphology leading to poor interfacial contact with the underneath layer thereby restricting the power conversion efficiency (PCE) of C-PSCs. Herein, a simple approach is presented to prepare liquid metal/carbon composite electrodes by uniformly dispersing liquid gallium droplets into CEs to enhance both the electrical conductivity and interfacial contact between carbon and the adjacent layer. Compared to control devices without Ga, the Ga-embedded carbon also creates a more favorable energy band alignment with the hole transport layer underneath for efficient hole transport, thus suppressing recombination at the interfaces. By optimizing the weight ratio between Ga and the carbon paste, the corresponding C-PSCs deliver an optimum PCE of 13.99% with a higher fill factor (68.95%) compared to pristine C-PSCs (PCE = 13.13%). In addition, the Ga-containing devices demonstrate reinforced thermal stability with 65% efficiency retention after 1800 min under a thermal stress of 80 °C without encapsulation. 相似文献
89.
This paper studies a bearing‐only–based formation control problem for a group of single‐integrator agents with directed cycle sensing topology. In a 2‐dimensional space, a necessary and sufficient condition for the set of desired bearing vectors to be feasible is derived. Then, we propose a bearing‐only control law for every agent and prove that the formation asymptotically converges to a formation specified by a set of feasible desired bearing vectors. Analysis of the equilibrium formations in the plane for a 3‐agent system and subsequent extension to an n‐agent system is provided. We further extend the analysis on directed triangular formation into a 3‐dimensional space. Finally, simulations validate the theoretical results. 相似文献
90.
Hong Khanh Dieu Nguyen Toan Dang Nguyen Dung Ngoc Hoang Duc Sy Dao Thao Tien Nguyen Limphirat Wanwisa Lan Linh Hoang 《Korean Journal of Chemical Engineering》2017,34(2):314-319
Hydrotalcite-like compound containing metal cations such as Mg2+, Al3+ and Ni2+ was characterized using Ni K-edge EXAFS and in situ Ni K-edge XANES techniques for clarifying its bonding environment around Ni2+ sites and structure changes during calcination from room temperature to 550 °C, respectively. At the fixed molar ratio of Mg/Ni/Al of 2/1/1, the results obtained from EXAFS analysis showed a slight blue shift before and after the calcination at 550 °C and a reduction in white line peak; the best fits of the two samples revealed tiny change in coordination number about 7 for Ni-O path but considerable difference for Ni-Mg(Al) path from about 4.5 to 9.5, confirming a modification from brucite like to mixed oxide structure. On the other hand, bond distances of the Ni-O and Ni-Mg paths nearly fixed at about 2.06 Å to 3.0 Å reflected stability of the cationic bond order on each plane, but partial collapse and decomposition of the interlayer formed by water molecules and anion CO 3 2? after the calcination. Linear combination fit extracted from the in situ Ni K-edge XANES also confirmed the changes along with the calcination such as slow and fast decreases of brucite fraction at 150 °C and 330 °C, respectively, in corresponding to the mixed oxide fraction increases. The achieved bonding structures were also applied to explain acid-base occurrence of the hydrotalcite-like material, especially the acid sites generated by different static charges along with the bonds. The explanation was illustrated by NH3-TPD method. 相似文献