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991.
Youn Tae Kim Chi Hoon Jun Jong-Tae Baek Hyung Joun Yoo Sang-Koo Chung 《Journal of Electronic Materials》1995,24(10):1413-1417
In this study, we have investigated sensitivities of the ion implanted silicon wafers processed by rapid thermal annealing
(RTA), which can reveal the variation of sheet resistance as a function of annealing temperature as well as implantation parameters.
All the wafers were sequentially implanted by the arsenic or phosphorous implantations at 40, 80, and 100 keV with the dose
level of 1014 to 2 × 1016 ions/cm2. Rapid thermal annealing was carried out for 10 s by the infrared irradiation at a temperature between 850 and 1150°C in
the nitrogen ambient. The activated wafer was characterized by the measurements of the sheet resistance and its uniformity
mapping. The values of sensitivities are determined from the curve fitting of the experimental data to the fitting equation
of correlation between the sheet resistance and process variables. From the sensitivity values and the deviation of sheet
resistance, the optimum process conditions minimizing the effects of straggle in process parameters are obtained. As a result,
a strong dependence of the sensitivity on the process variables, especially annealing temperatures and dose levels is also
found. From the sensitivity analysis of the 10 s RTA process, the optimum values for the implant dose and annealing temperature
are found to be in the range of 1016 ions/cm2 and 1050-1100°C, respectively. The sensitivity analysis of sheet resistance will provide valuable data for accurate activation
process, offering a guideline for dose monitoring and calibration of ion implantation process. 相似文献
992.
Deale O.C. Ng K.T. Kim E.J. Lerman B.B. 《IEEE transactions on bio-medical engineering》1995,42(12):1208-1211
A high common mode voltage (Vcm) relative to earth ground is produced on the myocardium during the delivery of a defibrillator pulse and can generate a differential error signal when potential gradients are recorded with bipolar electrodes and isolation amplifiers. The error signal is proportional to Vcm, and therefore, a reduction in Vcm improves the accuracy of the potential gradient data. Experiments were conducted on 5 dogs to determine whether Vcm can be controlled using a bridge circuit. The bridge circuit consisted of a 5 kΩ power rheostat in parallel with the transthoracic resistance of the dog. The variable contact of the rheostat was connected to earth ground, and by adjusting the rheostat, Vcm on the myocardium could be varied. In each dog, 20 A shocks were delivered through stainless steel transthoracic electrodes. Point contact electrodes sutured to the epicardium were used to measure Vcm. It was determined that Vcm could be reduced to approximately zero at a given electrode on the heart. In addition, for the 5 dogs studied, the maximum measured Vcm on the heart was only 10% of the transthoracic voltage when the bridge circuit was balanced for an interior point in the heart 相似文献
993.
Watson M.E. Chilla J.L.A. Rocca J.J. Kim J.-W. Lile D.L. Vogt T.J. Robinson G.Y. 《Quantum Electronics, IEEE Journal of》1995,31(2):254-260
We report modulation saturation and time response measurements on InGaAs-InGaP MQW modulators. The measurements yield a saturation intensity of (3.7±0.1) kW/cm2 for a 0-10 V swing and switching times between 10 and 90 ns, depending on the bias voltage and incident light intensity. The observed dependence indicates that field screening due to carrier build-up is the dominant physical mechanism determining both the speed and the saturation intensity. This conclusion is supported by results of theoretical calculations 相似文献
994.
Sehun Kim Soo-Hyun Kim 《International Journal of Satellite Communications and Networking》1995,13(1):31-37
We consider the satellite cluster scheduling problem, which is one of the most interesting problems in the satellite communication scheduling area. This problem is known to be NP-complete, and a couple of heuristic algorithms have been developed. In this paper, we suggest another algorithm for this problem which has the same computational complexity as the best existing one and provides much better solution quality. Extensive computational simulation results are reported. 相似文献
995.
996.
Kan Zhang Jung Kyu Kim Ming Ma Sang Youp Yim Chang‐Lyoul Lee Hyunjung Shin Jong Hyeok Park 《Advanced functional materials》2016,26(25):4527-4534
Photocatalytic hydrogen (H2) evolution requires efficient electron transfer to catalytically active sites in competition with charge recombination. Thus, controlling charge‐carrier dynamics in the photocatalytic H2 evolution process is essential for optimized photocatalyst nanostructures. Here, the efficient delocalization of electrons is demonstrated in a heterostructure consisting of optimized MoS2 tips and CdS nanorods (M‐t‐CdS Nrs) synthesized by amine‐assisted oriented attachment. The heterostructure achieves photocatalytic H2 activity of 8.44 mmol h?1 g?1 with excellent long‐term durability (>23 h) without additional passivation under simulated solar light (AM 1.5, 100 mW cm?2). This activity is nearly two orders of magnitude higher than that of pure CdS Nrs. The impressive photocatalytic H2 activity of M‐t‐CdS Nrs reflects favorable charge‐carrier dynamics, as determined by steady‐state PL and time‐correlated single photon counting correlation analysis at low temperature. The MoS2 cocatalysts precisely located at the end of the CdS Nrs exhibit ultrafast charge transfer and slow charge recombination via spatially localized deeper energy states, resulting in a highly efficient H2 evolution reaction in lactic acid containing an electrolyte. 相似文献
997.
Effective Polysulfide Rejection by Dipole‐Aligned BaTiO3 Coated Separator in Lithium–Sulfur Batteries 下载免费PDF全文
Taeeun Yim Seung Ho Han Nam Hwan Park Min‐Sik Park Ji Hoon Lee Jaeho Shin Jang Wook Choi Yongju Jung Yong Nam Jo Ji‐Sang Yu Ki Jae Kim 《Advanced functional materials》2016,26(43):7817-7823
Although the exceptional theoretical specific capacity (1672 mAh g?1) of elemental sulfur makes lithium–sulfur (Li–S) batteries attractive for upcoming rechargeable battery applications (e.g., electrical vehicles, drones, unmanned aerial vehicles, etc.), insufficient cycle lives of Li–S cells leave a substantial gap before their wide penetration into commercial markets. Among the key features that affect the cyclability, the shuttling process involving polysulfides (PS) dissolution is most fatal. In an effort to suppress this chronic PS shuttling, herein, a separator coated with poled BaTiO3 or BTO particles is introduced. Permanent dipoles that are formed in the BTO particles upon the application of an electric field can effectively reject PS from passing through the separator via electrostatic repulsion, resulting in significantly improved cyclability, even when a simple mixture of elemental sulfur and conductive carbon is used as a sulfur cathode. The coating of BTO particles also considerably suppresses thermal shrinkage of the poly(ethylene) separator at high temperatures and thus enhances the safety of the cell adopting the given separator. The incorporation of poled particles can be universally applied to a wide range of rechargeable batteries (i.e., metal‐air batteries) that suffer from cross‐contamination of charged species between both electrodes. 相似文献
998.
999.
Kim K Yun S Lee S Nam S Yoon YJ Cheon C 《IEEE transactions on bio-medical engineering》2012,59(4):1005-1011
This paper presents a high-speed and high-efficiency capsule endoscopy system. Both a transmitter and a receiver were optimized for its application through an analysis of the human body channel. ON-OFF keying modulation is utilized to achieve low power consumption of the in-body transmitter. A low drop output regulator is adopted to prevent performance degradation in the event of a voltage drop in the battery. The receiver adopts superheterodyne structure to obtain high sensitivity, considering the link budget from the previous analysis. The receiver and transmitter were fabricated using the CMOS 0.13-μm process. The output power of the transmitter is -1.6 dB·m and its efficiency is 27.7%. The minimum sensitivity of the receiver is -80 dB·m at a bit error ratio (BER) of 3 × 10 (-6). An outer wall loop antenna is adopted for the capsule system to ensure a small size. The integrated system is evaluated using a liquid human phantom and a living pig, resulting in clean captured images. 相似文献
1000.
Shuyan Gao Naoto Koshizaki Hideo Tokuhisa Emiko Koyama Takeshi Sasaki Jae‐Kwan Kim Joonghyun Ryu Deok‐Soo Kim Yoshiki Shimizu 《Advanced functional materials》2010,20(1):78-86
Colloidal Au‐amplified surface plasmon resonance (SPR), like traditional SPR, is typically used to detect binding events on a thin noble metal film. The two major concerns in developing colloidal Au‐amplified SPR lie in 1) the instability, manifested as a change in morphology following immersion in organic solvents and aqueous solutions, and 2) the uncontrollable interparticle distance, determining probe spacing and inducing steric hindrance between neighboring probe molecules. This may introduce uncertainties into such detecting techniques, degrade the sensitivity, and become the barricade hampering colloidal Au‐based transducers from applications in sensing. In this paper, colloidal Au‐amplified SPR transducers are produced by using ultrathin Au/Al2O3 nanocomposite films via a radio frequency magnetron co‐sputtering method. Deposited Au/Al2O3 nanocomposite films exhibit superior stability, and average interparticle distances between Au nanoparticles with similar average sizes can be tuned by changing surface coverage. These characteristics are ascribed to the spacer function and rim confinement of dielectric Al2O3 and highlight their advantages for application in optimal nanoparticle‐amplified SPR, especially when the probe size is smaller than the target molecule size. This importance is demonstrated here for the binding of protein (streptavidin) targets to the probe (biotin) surface. In this case, the dielectric matrix Al2O3 is a main contributor, behaving as a spacer, tuning the concentration of Au nanoparticles, and manipulating the average interparticle distance, and thus guaranteeing an appropriate number of biotin molecules and expected near‐field coupling to obtain optimal sensing performance. 相似文献