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141.
Daniil Bash Yongqiang Cai Vijila Chellappan Swee Liang Wong Xu Yang Pawan Kumar Jin Da Tan Anas Abutaha Jayce JW Cheng Yee-Fun Lim Siyu Isaac Parker Tian Zekun Ren Flore Mekki-Berrada Wai Kuan Wong Jiaxun Xie Jatin Kumar Saif A. Khan Qianxiao Li Tonio Buonassisi Kedar Hippalgaonkar 《Advanced functional materials》2021,31(36):2102606
Combining high-throughput experiments with machine learning accelerates materials and process optimization toward user-specified target properties. In this study, a rapid machine learning-driven automated flow mixing setup with a high-throughput drop-casting system is introduced for thin film preparation, followed by fast characterization of proxy optical and target electrical properties that completes one cycle of learning with 160 unique samples in a single day, a > 10 × improvement relative to quantified, manual-controlled baseline. Regio-regular poly-3-hexylthiophene is combined with various types of carbon nanotubes, to identify the optimum composition and synthesis conditions to realize electrical conductivities as high as state-of-the-art 1000 S cm−1. The results are subsequently verified and explained using offline high-fidelity experiments. Graph-based model selection strategies with classical regression that optimize among multi-fidelity noisy input-output measurements are introduced. These strategies present a robust machine-learning driven high-throughput experimental scheme that can be effectively applied to understand, optimize, and design new materials and composites. 相似文献
142.
Jae-Hak Lim Dong Ho Park 《Reliability, IEEE Transactions on》1995,44(2):291-296
The authors consider a life distribution which shows a trend change in its mean residual life (MRL). The problem of testing such a trend change has been of great interest in reliability analysis. The authors propose a new procedure for testing the exponentiality against IDMRL or DMIRL, assuming that the proportion of the population, p, that dies at or before the change point of MRL is known. Their test provides a new competitor to the known test procedures, such as the Guess, Hollander, Proschan test and the Aly test. Based on the empirical powers of these tests against lognormal alternatives, their test outperforms the others for most sample sizes and most values of p and that all three tests achieve high power in detecting the trend change of MRL when p is very small and very large 相似文献
143.
Tae‐Woo Lee Mu‐Gyeom Kim Sang Hun Park Sang Yeol Kim Ohyun Kwon Taeyong Noh Jong‐Jin Park Tae‐Lim Choi Jong Hyeok Park Byung Doo Chin 《Advanced functional materials》2009,19(12):1863-1868
The short device lifetime of blue polymer light‐emitting diodes (PLEDs) is still a bottleneck for commercialization of self‐emissive full‐color displays. Since the cathode in the device has a dominant influence on the device lifetime, a systematic design of the cathode structure is necessary. The operational lifetime of blue PLEDs can be greatly improved by introducing a three‐layer (BaF2/Ca/Al) cathode compared with conventional two‐layer cathodes (BaF2/Al and Ba/Al). Therefore, the roles of the BaF2 and Ca layers in terms of electron injection, luminous efficiency, and device lifetime are here investigated. For efficient electron injection, the BaF2 layer should be deposited to the thickness of at least one monolayer (~3 nm). However, it is found that the device lifetime does not show a strong relation with the electron injection or luminous efficiency. In order to prolong the device lifetime, sufficient reaction between BaF2 and the overlying Ca layer should take place during the deposition where the thickness of each layer is around that of a monolayer. 相似文献
144.
Teck Beng Lim Lei Zhu 《Microwave and Wireless Components Letters, IEEE》2009,19(10):632-634
A differential-mode wideband bandpass filter (BPF) on microstrip line is proposed with good common-mode suppression. A four port two stage branch-line differential-mode BPF is first designed. Then, open circuited stubs are attached to the middle of two of the vertical branches. As such, its two-port bisection becomes a bandpass or bandstop filtering topology under differental- or common-mode excitations, respectively. The lengths and widths of these stubs can be properly adjusted to produce a highly attenuated and widened stopband under the common-mode operation. Finally, a wideband differential-mode BPF is designed and fabricated. The predicted and measured performances are in good agreement with each other, showing good common-mode suppression with an insertion loss higher than 20 dB over the differential-mode passband with a fractional bandwidth of 65%. 相似文献
145.
Micromachining is gaining popularity due to recent advancements in Micro Electro Mechanical Systems. Using conventional micromachining,
it is relatively difficult to produce moving components in the order of microns. In this study, an attempt is made to fabricate
microstructures using a combination of turning and electrodischarge machining (EDM). Several sets of experiments have been
performed to study the characteristics of the hybrid machining process. From the experiments, it has been observed that a
higher form of accuracy could be obtained by integrating the on-machine fabrication of the tool and by subsequently using
the same tool for EDM. The main cause of the form error is due to the deflection of the shaft during turning. Hence, an attempt
is made to observe the deflection of the shaft using a deflection sensor. The influence of micro-EDM parameters such as feed
rate, discharge circuits, and gap control parameters on material removal rate and tool wear is also discussed in this study. 相似文献
146.
Sung-Chan Kim Baek-Seok Ko Tae-Jong Baek Byeong-Ok Lim An D. Dong-Hoon Shin Jin-Koo Rhee 《Microwave and Wireless Components Letters, IEEE》2005,15(10):652-654
The hybrid ring coupler was designed and fabricated on a GaAs substrate using surface micromachining techniques, which adopted dielectric-supported air-gapped microstrip line (DAML) structure. The fabrication process of DAML is compatible with the standard monolithic microwave integrated circuit (MMIC) techniques, and the hybrid ring coupler can be simply integrated into a plane-structural MMIC. The fabricated hybrid ring coupler shows wideband characteristics of the coupling loss of 3.57 /spl plusmn/ 0.22dB and the transmission loss of 3.80 /spl plusmn/ 0.08dB across the measured frequency range of 85 to 105GHz. The isolation characteristics and output phase differences are -34dB and 180/spl plusmn/1/spl deg/, at 94GHz, respectively. 相似文献
147.
Hwang S. H. Lim J. W. Lee W.-J. Kim G. W. Cho C. H. An J. B. Jung K. Y. Cha K. S. Rho B. S. 《Photonics Technology Letters, IEEE》2010,22(3):167-169
148.
Protein extraction solutions such as aqueous solutions of sodium hydroxide (0.1 and 0.2 %), sodium lauryl sulfate (SLS, 1.2 %) containing sodium sulfite (0.12 %), and dodecylbenzene sulfonate (DoBS, 1.2 %) containing sodium sulfite (0.12 %) were compared in their protein removal efficiencies during isolation of starch from a rice flour (Ilpumbyo, a nonwaxy Korean rice variety). In addition, the pasting properties of the isolated starch was compared. More than 80 % of the flour protein was extracted in 1 h by stirring the dispersion (1:3, w/v) at room temperature. Repeating the extractions (1 or 2 h for each step) with fresh solution significantly increased the protein removal efficiency. When the extraction in 0.2 % NaOH was repeated four times (1 h for each step) at 25°C, the residual protein content in the isolated rice starch was 0.9 % (DB), equivalent to 86 % removal of the rice protein. Raising the extraction temperature slightly increased the protein solubility, but starch loss also became significant. Among the solutions, DoBS was most effective in removing rice protein whereas SLS was least. The residual protein content had a critical role in determining the pasting characteristics of the isolated starch, showing a negative correlation to the peak viscosity of the starch paste, but a positive correlation to the pasting temperature. 相似文献
149.
Bryant A.T. Yalan Wang Finney S.J. Tee Chong Lim Palmer P.R. 《Power Electronics, IEEE Transactions on》2007,22(2):374-383
Feedback control of insulated gate bipolar transistors (IGBTs) in the active region can be used to regulate the device switching trajectory. This facilitates series connection of devices without the use of external snubber networks. Control must be achieved across the full active region of the IGBT and must balance a number of conflicting system goals including diode recovery. To date, the choice of control parameters has been a largely empirical process. This paper uses accurate device models and formalized optimization procedures to evaluate IGBT active voltage controllers. A detailed optimization for the control of IGBT turn-on is presented in this paper 相似文献
150.
In this paper, we propose the analytical approach for amplify-and-forward (AF) opportunistic relaying schemes (ORS). When operation of AF-ORS consists of relay selection and data transmission phases based on pilot symbol assisted-channel estimation (PSA-CE) methods over quasi-static Rayleigh fading channels, we show that the relay selection phase can be implemented by pilots symbols transmission for source-relay and relay-destination. Moreover, the feedback method for the selected relay index is proposed to have a simple fashion. Then, we investigate the effects of both a channel estimation error and an estimated noise variance, which are obtained by PSA-CE methods, on the received signal-to-noise ratio (SNR). The average SNR loss is also derived in terms with the number of pilots in PSA-CE methods. Moreover, the average symbol error rate, the outage probability, and the normalized channel capacity of the ORS are derived in approximated closed-form expressions for an arbitrary link SNR when the channel state information in the source-relay-destination link is estimated based on transmitted pilots symbols. As the number of pilot symbols, the derived analytical approach is verified, and by comparing it with simulation results, the accuracy is demonstrated. In addition, it is verified that the effect of the feedback error can be neglected for PAS-CE methods over quasi-static fading channels. 相似文献