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981.
The influence of current density on the discharge reaction of Li–S batteries is investigated by discharge tests (first discharge curve), differential scanning calorimetry (DSC), X-ray diffraction (XRD) (discharge products), and scanning electron microscopy (the surface morphology of sulfur electrodes). The first discharge capacity and the plateau potential both decrease with increasing current density. When the current density is increased from 100 to 1600 mA g−1 S, the discharge capacity decreases from 1178 to 217 mAh g−1 S. 相似文献
982.
Jong-Seon Kim Hyo-Jun Ahn Ho-Suk Ryu Dong-Ju Kim Gyu-Bong Cho Ki-Won Kim Tae-Hyun Nam Jou Hyeon Ahn 《Journal of power sources》2008
The discharge properties of a Na/Ni3S2 cell using 1 M NaCF3SO3 in tetra(ethylene glycol)dimethyl ether liquid electrolyte were investigated at room temperature. The products were characterized by X-ray diffraction, scanning electron microscopy and energy dispersive spectroscopy. Electrochemical properties of Na/Ni3S2 cells were also presented by cyclic voltammetry and the galvanostatic current method. Na/Ni3S2 cells have an initial discharge capacity of 420 mAh g−1 with a plateau potential at 0.94 V versus Na/Na+. After the first discharge, Ni3S2 and Na react at room temperature and then form sodium sulfide (Na2S) and nickel. Sodium ion can be partially deintercalated from Na2S charge reaction. The discharge process can be explained as follows: Ni3S2 + 4Na ↔ 3Ni + 2Na2S. 相似文献
983.
984.
985.
A highly efficient low-emission co-generation system using a 2000-cc common-rail direct-injection (CRDI) diesel engine with an after-treatment device (re-combustor) is developed. The co-generation concept is utilized to produce electric power by a generator as well as to recover waste heat from the exhaust gases. A re-combustor is installed at the exhaust gas outlet to perform secondary burning of the exhaust gases, resulting in an improvement of the system's thermal efficiency as well as a reduction of exhaust gas emissions. The main components of the re-combustor are coiled Pyromax wires installed in a ceramic housing, diesel oxidation catalyst (DOC), and diesel particulate filter (DPF). The tests are conducted at four water flow rates (10, 15, 20, and 25 LPM) and four electric power outputs (5, 15, 25, and 35 kW). In general, a great deal of time and expense are required to determine the optimum experimental conditions for the maximum efficiency of a co-generation system. However, in the present study, the optimum experimental conditions for the present system are found using the Taguchi method and analysis of variance (ANOVA), resulting in significant savings of time and expense. The results show that the present co-generation system achieves a maximum total efficiency of 85.7%, and a significant reduction of CO, NOx, and PM by 73.3%, 34.3%, and 94%, respectively. 相似文献
986.
To meet the rapidly changing customer needs in the manufacturing environment, future manufacturing systems must be dynamically and flexibly reconfigured. The fractal manufacturing system (FrMS) is one of the new manufacturing paradigms that can meet such requirements. The basic component of the FrMS is referred to as a fractal. Consisting of self-similar agents, each fractal autonomously cooperates and negotiates with others to coordinate its tasks. Dynamic restructuring process (DRP) supports reorganization of the system configurations so that the FrMS can be adapted to dynamically changing environments. Although traditional approaches have endeavoured to demonstrate reconfigurability of a manufacturing system, they are not accurate enough to meet the requirements of circumstances such as high-level autonomy in reconfiguring the system architecture. In this paper, therefore, the DRP, which embodies self-reconfigurability of a system, is proposed focusing on the FrMS. To check the effectiveness of the DRP, we have developed the FrMS test bed and conducted the experimentation on the DRP. A simulation study has been conducted to show the effectiveness of the DRP under an illustrative situation. 相似文献
987.
Seung-Hee Kang Eui Sup Shin Ki-Wahn Ryu Jun-shin Lee 《Journal of Mechanical Science and Technology》2013,27(5):1321-1327
A new blockage-correction method for the separated flows around the airfoil of a wind turbine blade was developed for the wall interference correction of the closed test-section wind tunnel. A wind tunnel test was performed for the airfoil at an angle-of-attack range of 0–180°. The freestream velocity was 15 m/s, which corresponds to a Reynolds number of 2.3 × 105 based on the chord. Then a blockage correction for the separated flows was obtained with respect to the multiplication of the blocking area and the separation drag coefficient based on the test. The present method was validated by comparing the corrected results with those of the existing classical and measured-boundary-condition methods. The results of the classical method are similar to those of the measured-boundary-condition method at the attached flow region; however, at high angles of attack, the difference in the corrected results between the classical and MBC methods becomes significantly large. The present method is in good agreement with the measured-boundary-condition method, enabling better wall corrections than the classical method in post-stall region. 相似文献
988.
Jongdae Park Hoyoung Ryu Soon Seok Lee Sueng Jae Bae Ju Yong Lee Mihui Kim Min Young Chung 《International Journal of Network Management》2013,23(3):155-171
In order to increase the capacity of wireless communication networks with minor changes and low cost, internetworking between cellular networks and wireless local area networks (WLANs) is considered as an attractive solution. In the internetworking of cellular networks and WLANs, a cost‐efficient vertical handover mechanism is required for seamless service provision. In this paper, we propose a cost‐efficient vertical handover mechanism for the packet‐based cellular networks and WLAN internetworking, where HMIPv6 and IEEE 802.21 are complementarily integrated to optimize the handover procedures. To design the mechanism, we introduce pre‐binding update and hierarchical packet forwarding concepts which can reduce handover signaling cost and delay. A mathematical model for handover rates and costs is proposed in order to analyze the proposed mechanism. In performance evaluation, we investigate how various factors affect handover rates and costs, and compare the proposed mechanism against the conventional mechanism. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
989.
Ryu Deok-Seon Kim Seon-Hee Oh Seung-Min Lee Hyeong-Seon Jeong Jae-Han Kim Soo-Hwan Lee Dong-Seok 《Food science and biotechnology》2011,20(1):267-271
In this study, we investigated the immunosuppressive effects of water-soluble barley β-glucan (BP) in mouse immune cells.
The BP was prepared from barley (Hordeum vulgare), and it suppressed the proliferation of splenocytes stimulated with concanavalin A (Con A), interleukin-2 (IL-2), and alloantigenic
splenocytes in a dose-dependent manner (0.25, 0.5, and 1mg/mL). Furthermore, the death-inducing activities of cytotoxic T
lymphocytes (CTLs) and lymphokine-activated killer cells (LAKs) in alloantigen-reactive splenocytes were significantly suppressed
by more than 50%. Also, the production of IL-2 in the splenocytes decreased. These results suggest that these barley-originated
polysaccharides can be used as potential immunosuppressive agents. 相似文献
990.
O'Connor PJ Quiter ES Rush WA Wiest M Meland JT Ryu S 《The Joint Commission journal on quality improvement》1999,25(2):68-77
BACKGROUND: A worsening of blood pressure control has occurred in the 1990s despite the availability of sophisticated technologic, pharmacologic, and educational advances applicable to hypertension care. Clinical guidelines that are intended to improve hypertension care by making specific recommendations on drug use, frequency of follow-up care, and target levels of blood pressure have been developed. METHODS: The Institute for Clinical Systems Integration's (ICSI's; Minneapolis) Hypertension Treatment Guideline was developed in 1994 and is updated annually. This study employed a quasi-experimental, before-and-after design at two medical groups to assess changes in the care provided to patients 18 years of age and older with identified hypertension (International Classification of Diseases-9 codes 401.0, 401.1, or 401.9). RESULTS: Among adults with hypertension, the proportion meeting the blood pressure goal of < 140/90 mm Hg increased from 36.8% (of 685 patients) preguideline to 50.3% (of 928 patients) postguideline (chi-square = 29.4, p < 0.001); the mean arterial pressure decreased from 102.7 mm Hg to 99.4 mm Hg (t = 5.45, p < 0.001). Cohort analysis of patients enrolled at both points in time confirmed these findings and showed an increase in the number of office visits from 5.4 to 6.7 visits per patient per year after guideline implementation (F = 10.9, p = 0.001). The use of a guideline-recommended medication for treatment of blood pressure was 35.9% preguideline and 36.2% postguideline. CONCLUSIONS: Implementation of a hypertension treatment guideline in primary care clinics was related to significantly improved hypertension control. Identification, tracking, and active outreach to patients with hypertension were used by all clinics. 相似文献