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991.
Jia Shi Peng Yu Fucai Liu Peng He Rui Wang Liang Qin Junbo Zhou Xin Li Jiadong Zhou Xinyu Sui Shuai Zhang Yanfeng Zhang Qing Zhang Tze Chien Sum Xiaohui Qiu Zheng Liu Xinfeng Liu 《Advanced materials (Deerfield Beach, Fla.)》2017,29(30)
Nonlinear 2D layered crystals provide ideal platforms for applications and fundamental studies in ultrathin nonlinear optical (NLO) devices. However, the NLO frequency conversion efficiency constrained by lattice symmetry is still limited by layer numbers of 2D crystals. In this work, 3R MoS2 with broken inversion symmetry structure are grown and proved to be excellent NLO 2D crystals from monolayer (0.65 nm) toward bulk‐like (300 nm) dimension. Thickness and wavelength‐dependent second harmonic generation spectra offer the selection rules of appropriate working conditions. A model comprising of bulk nonlinear contribution and interface interaction is proposed to interpret the observed nonlinear behavior. Polarization enhancement with two petals along staggered stacking direction appears in 3R MoS2 is first observed and the robust polarization of 3R MoS2 crystal is caused by the retained broken inversion symmetry. The results provide a new arena for realizing ultrathin NLO devices for 2D layered materials. 相似文献
992.
Rubentheran Sivagurunathan Saijod Lau Tze Way Linkesvaran Sivagurunathan Mohd. Yuhazri Yaakob 《Applied Composite Materials》2018,25(6):1401-1417
The usage of composite materials have been improving over the years due to its superior mechanical properties such as high tensile strength, high energy absorption capability, and corrosion resistance. In this present study, the energy absorption capability of circular jute/epoxy composite tubes were tested and evaluated. To induce the progressive crushing of the composite tubes, four different types of triggering mechanisms were used which were the non-trigger, single chamfered trigger, double chamfered trigger and tulip trigger. Quasi-static axial loading test was carried out to understand the deformation patterns and the load-displacement characteristics for each composite tube. Besides that, the influence of energy absorption, crush force efficiency, peak load, mean load and load-displacement history were examined and discussed. The primary results displayed a significant influence on the energy absorption capability provided that stable progressive crushing occurred mostly in the triggered tubes compared to the non-triggered tubes. Overall, the tulip trigger configuration attributed the highest energy absorption. 相似文献
993.
Chien DN Tanaka K Tanaka M 《Journal of the Optical Society of America. A, Optics, image science, and vision》2003,20(8):1608-1616
The boundary integral equations that are called guided-mode extracted integral equations are applied to the investigation of the power-coupling-properties between two arbitrarily ended dielectric slab waveguides. The integral equations derived in this paper can be solved by the conventional boundary-element method. The reflection and coupling coefficients of the guided wave, as well as the scattering power, are calculated numerically for the case of incident TE guided-mode waves. The results presented are checked by the energy conservation law and the reciprocity theorem. Numerical results are presented for several geometries of coupling, including systems with three-layered symmetrical and asymmetrical slab waveguides. 相似文献
994.
Trifunctional TiO2 Nanoparticles with Exposed {001} Facets as Additives in Cobalt‐Based Porphyrin‐Sensitized Solar Cells 下载免费PDF全文
Peng Zhai Tsung‐Yu Hsieh Chen‐Yu Yeh Kamani Sudhir K Reddy Chi‐Chang Hu Jhih‐Hao Su Tzu‐Chien Wei Shien‐Ping Feng 《Advanced functional materials》2015,25(38):6093-6100
In this study, highly mesoporous TiO2 composite photoanodes composed of functional {001}‐faceted TiO2 nanoparticles (NPs) and commercially available 20 nm TiO2 NPs are employed in efficient porphyrin‐sensitized solar cells together with cobalt polypyridyl‐based mediators. Large TiO2 NPs (approximately 50 nm) with exposed {001} facets are prepared using a fast microwave‐assisted hydrothermal (FMAH) method. These unique composite photoanodes favorably mitigate the aggregation of porphyrin on the surface of TiO2 NPs and strongly facilitate the mass transport of cobalt‐polypyridyl‐based electrolytes in the mesoporous structure. Linear sweep voltammetry reveals that the transportation of Co(polypyridyl) redox is a diffusion‐controlled process, which is highly dependent on the porosity of TiO2 films. Electrochemical impedance spectroscopy confirms that the FMAH TiO2 NPs effectively suppress the interfacial charge recombination toward [Co(bpy)3]3+ because of their oxidative {001} facets. In an optimal condition of 40 wt% addition of FMAH TiO2 NPs in the final formula, the power conversion efficiency of the dye‐sensitized cells improves from 8.28% to 9.53% under AM1.5 (1 sun) conditions. 相似文献
995.
996.
Mingzhi Jiao Nguyen Van Duy Nguyen Viet Chien Nguyen Duc Hoa Nguyen Van Hieu Klas Hjort Hugo Nguyen 《International Journal of Hydrogen Energy》2017,42(25):16294-16304
In this study, we used a low-temperature hydrothermal technique to fabricate arrays of sensors with ZnO nanorods grown on-chip. The sensors on the glass substrate then were sputter decorated with Pd at thicknesses of 2, 4, and 8 nm and annealed at 650 °C in air for an hour. Scanning electron microscopy, high resolution transmission microscopy, X-ray diffraction, and surface analysis by X-ray photoelectron spectroscopy characterization demonstrated that decoration of homogenous PdO nanoparticles on the surface of ZnO nanorods had been achieved. The sensors were tested against three reducing gases, namely hydrogen, ethanol, and ammonia, at 350, 400, and 450 °C. The ZnO nanorods decorated with PdO particles from the 2 and 4 nm layers showed the highest responses to H2 at 450 and 350 °C, respectively. These samples also generally exhibited better selectivity for hydrogen than for ethanol and ammonia at the same concentrations and at all tested temperatures. However, the ZnO nanorods decorated with PdO particles from the 8 nm layer showed a reverse sensing behaviour compared with the first two. The sensing mechanism behind these phenomena is discussed in the light of the spillover effect of hydrogen in contact with the PdO particles as well as the negative competition of the PdO thin film formed between the sensor electrodes during sputter decoration, Pd–Zn heterojunction that forms at high temperature and thus influences the conductivity of the ZnO nanorods. 相似文献
997.
Motivated by applications to root-cause identification of faults in multistage manufacturing processes that involve a large number of tools or equipment at each stage, we consider multiple testing in regression models whose outputs represent the quality characteristics of a multistage manufacturing process. Because of the large number of input variables that correspond to the tools or equipments used, this falls in the framework of regression modeling in the modern era of big data. On the other hand, with quick fault detection and diagnosis followed by tool rectification, sparsity can be assumed in the regression model. We introduce a new approach to address the multiple testing problem and demonstrate its advantages over existing methods. We also illustrate its performance in an application to semiconductor wafer fabrication that motivated this development. Supplementary materials for this article are available online. 相似文献
998.
Wei-Ting Kary Chien Yuanzi Lester Yin 《Journal of Failure Analysis and Prevention》2018,18(6):1490-1502
Design for test (DFT) has been widely applied to digital circuit failure analysis (FA) in semiconductor industries. The FA methods based on DFT involve layer-by-layer checks using a polisher and an SEM for defect identification and localization. Yet these methods have limitations with high risks of sample damages. Besides, they are highly dependent on the technical proficiencies of operators and, thus, they are not effective for precise defect isolations. This problem has been aggravated, especially at advanced nodes. The nano-probing electron beam absorbed current (EBAC) has significant advantages on precisely locating defects. This technique is to directly identify specific defects without layer-by-layer checks. Therefore, it can minimize sample damages during sample pretreatment. EBAC is an efficient technique to isolate the defects when the circuit is at the floating condition. Because the ground lines exist almost everywhere in a chip and they are for, e.g., electronic static discharge charge releases or connecting with sources for pickup, EBAC becomes a natural option for us. However, due to poor EBAC images, EBAC’s applications are restricted when the circuits under test have grounding paths. In this paper, we propose two enhanced EBAC analysis methods, based on the DFT and EBAC integrated system, for the defect isolations with grounded connections. It is the first time the DFT and EBAC integrated system is reported, and we successfully demonstrated EBAC applicability by real FA cases. 相似文献
999.
Highly Transparent and Integrable Surface Texture Change Device for Localized Tactile Feedback 下载免费PDF全文
Ankit Naveen Tiwari Mayank Rajput Nguyen Anh Chien Nripan Mathews 《Small (Weinheim an der Bergstrasse, Germany)》2018,14(1)
Human–machine haptic interaction is typically detected by variations in friction, roughness, hardness, and temperature, which combines to create sensation of surface texture change. Most of the current technologies work to simulate changes in tactile perception (via electrostatic, lateral force fields, vibration motors, etc.) without creating actual topographical transformations. This makes it challenging to provide localized feedback. Here, a new concept for on‐demand surface texture augmentation that is capable of physically forming local topographic features in any predesigned pattern is demonstrated. The transparent, flexible, integrable device comprises of a hybrid electrode system with conductive hydrogel, silver nanowires, and conductive polymers with acrylic elastomer as the dielectric layer. Desired surface textures can be controlled by a predesigned pattern of electrodes, which operates as independent or interconnected actuators. Surface features with up to a height of 0.155 mm can be achieved with a transformation time of less than a second for a device area of 18 cm2. High transparency levels of 76% are achieved due to the judicious choice of the electrode and the active elastomer layer. The capability of localized and controlled deformations makes this system highly useful for applications such as display touchscreens, touchpads, braille displays, on‐demand buttons, and microfluidic devices. 相似文献
1000.
The permeances of two palladium (Pd) membranes in pure H2, binary and ternary gas mixtures are investigated experimentally. With 10% of gas impurities (N2, CO2, or CO) in H2, the profiles of dimensionless permeance suggest that H2 permeation rate is lessened by approximately 50% to 90%, and the permeance reduced by the gas impurities is ranked as CO > CO2 > N2. By introducing a parameter of permeance resistance, which is the reciprocal of permeance, the permeance resistance in a ternary gas mixture can be predicted from the summation of individual permeance resistances in binary gas mixtures, revealing no synergistic effect exhibited from the interaction of contaminants. At least 75% and up to 100% of H2 in the gas mixtures can be recovered in the membrane system, and the maximum H2 recovery develops at the H2 partial pressure difference of 2 or 3 atm. In the Arrhenius‐type equation describing the relationship between the permeance and temperature, the activation energy is between approximately 2 and 18 kJ mole?1. In general, the permeances of the membranes in gas mixtures, especially in ternary gas mixtures, are more sensitive to temperature when compared with those in pure H2, stemming from lower activation energy exhibited. Copyright © 2017 John Wiley & Sons, Ltd. 相似文献