• Title/Summary/Keyword: First charge capacity

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The crystal growth and the electrochemical property of $LiZn_xMn{2-x}O_4(0\leqq x \leqq$ 0.15) cathode material ($LiZn_xMn{2-x}O_4(0\leqq x \leqq$ 0.15) 정극 활물질의 결정 성장 변화와 전기 화학적 특성)

  • Jeong, In-Seong;Gu, Hal-Bon;Lee, Jin;Park, Gye-Choon
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1999.05a
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    • pp.133-136
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    • 1999
  • We report on the electrochemical properly of LiZ $n_{x}$Mn $_{2-x}$ $O_4$ for different degrees of Zn substitution(x) Though all cathode material showed spinel phase based on cubic phase in X-ray diffraction, other peaks(M $n_2$ $O_3$ or M $n_3$ $O_4$) gradually exhibited and became intense with the increase of x vague in LiZ $n_{x}$Mn $_{2-x}$ $O_4$. In addtion, TG-DTA analysis exhibited that both LiM $n_2$ $O_4$ and LiZ $n_{0.1}$ M $n_{1.9}$ $O_4$ occurred the weight loss(TG) and the endothermic and exothermic reaction(DTA) until 80$0^{\circ}C$ When x=0.1 in LiZ $n_{x}$Mn $_{2-x}$ $O_4$ cathode materials showed the charge and discharge capacity of about 100mAh/g at first cycle and about 70mAh/g after tooth cycle.cle.e.cle.e.e.e.

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Synthesis and Electrochemical Performance of Mesoporous Hollow Sphere Shape LiMn2O4 using Silica Template (실리카 템플레이트를 이용하여 다공성 중공형태를 갖는 LiMn2O4 합성 및 전기화학적 특성 연구)

  • Ryu, Seong-Hyeon;Ryu, Kwang-Sun
    • Journal of the Korean Electrochemical Society
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    • v.14 no.3
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    • pp.184-190
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    • 2011
  • $LiMn_2O_4$ with mesoporous hollow sphere shape was synthesized by precipitation method with silica template. The synthesized $LiMn_2O_4$ has nanosized first particle and mesoporous hollow sphere shape. Silica template was removed by chemical etching method using NaOH solution. When the concentration of NaOH solution was increased, first particle size of manganese oxide was decrease and confirmed mesoporous hollow shpere shape. X-ray diffraction(XRD) patterns revealed that the synthesized samples has spinel structure with Fd3m space group. In case the ratio of silica and maganese salt increased, the size of first particles was decreased. The tetragoanal $LiMn_2O_4$ with micron size was synthesized at ratio of silica and manganese salt over 1 : 9. The prepared samples were assembled as cathode materials of Li-ion battery with 2032 type coin cell and their electrochemical properties are examined by charge-discharge and cyclic performance. Electrochemical measurements show that the nano-size particles had lower capacity than micron-size particles. But, cyclic performance of nano-size particles had better than that of micron-size particles.

Material Life Cycle Assessment of Graphene 2wt% Added to Li1.6Ni0.35Mn0.65O2 Half-Cell (그래핀 2wt%를 첨가한 Li1.6Ni0.35Mn0.65O2 Half-Cell의 물질 전 과정 평가)

  • CHO, KYOUNG-WON;LEE, YOUNG-HWAN;HAN, JEONG-HEUM;YU, JAE-SEON;HONG, TAE-WHAN
    • Transactions of the Korean hydrogen and new energy society
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    • v.31 no.1
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    • pp.132-137
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    • 2020
  • Lithium secondary batteries have become an important power source for portable electronic devices such as cellular phones, laptop computers. Presently, commercialized lithium-ion batteries use a LiCoO2 cathode. However, due to the high cost and environmental problems resulting from cobalt, an intensive search for new electrode materials is being actively conducted. Recently, solid solution LiMn1-xNixO2 have become attractive because of high capacity and enhanced safety at high voltages over 4.5 V. The Li1.6Ni0.35Mn0.65O2 compounds were conventionally prepared by a sol-gel method, which can produce the layered Li-Ni-Mn-O compounds with a high homogeneity. And by adding a graphene 2wt% the first charge-discharge voltage profiles was increased over Li1.6Ni0.35Mn0.65O2 compound. Also, the variation s of the discharge capacities with cycling showed a higher capacity retention rater. In this study, material lifecycle evaluation was performed to analyze the environmental impact characteristics of Li1.6Ni0.35Mn0.65O2 & graphene 2wt% half-cell manufacturing process. The software of material life cycle assessment was Gabi. Through this, environmental impact assessment was performed for each process. The environmental loads induced by Li1.6Ni0.35Mn0.65O2 & graphene 2wt% synthesis process were quantified and analyzed, and the results showed that the amount of power had the greatest impact on the environment.

Electrochemical characterization of LiCoO2 thin film by sol-gel process for annealing temperature and time (졸-겔법에 의해 합성한 리튬 코발트 산화물의 열처리 온도와 시간에 따른 전기 화학적 특성)

  • Roh, Tae-Ho;Yon, Seog-Joo;Ko, Tae-Seog
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.24 no.3
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    • pp.99-105
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    • 2014
  • $LiCoO_2$ thin film have received attention as cathodes of thin-film microbatteries. In this study, $LiCoO_2$ thin films were synthesized on Au substrates by sol-gel spin coating method and electrochemical properties were investigated under annealing temperature and time. The phycochemical properties of $LiCoO_2$ thin film were investigated by X-ray diffraction, scaning electron microscopy and atomic force microscopy. The electrochemical properties were characterized using galvanostatic charging/discharging cycling tests. From X-ray diffraction, as-grown films annealed at $550^{\circ}C$ and $750^{\circ}C$ are presumed to be spinel structure and a single phase of the layered-rock-salt, respectively. The RMS roughness and grain size of the films which annealed at $750^{\circ}C$ has similar values for annealing time 10 and 30 min, while for annealing time 120 min surface roughness, grain size increase and pore appearance were observed. The first discharge capacity of $LiCoO_2$ thin films annealed at $750^{\circ}C$ for 10, 30 and 120 min is about 54.5, 56.8 and $51.87{\mu}Ah/cm^2{\mu}m$, respectively. Corresponding capacity retention at 50th cycle is 97.25, 76.69, 77.19%.

Characterization on the electrochemical and structural properties of polyanion cathode material Li2MnSiO4/C depending on the synthesis process (합성 방법에 따른 Li2MnSiO4/C 다중음이온 양극활물질의 구조 및 전기화학적 성질)

  • Lee, Young-Lim;Chung, Young-Min;Song, Min-Seob;Ju, Jeh-Beck;Cho, Won-Il
    • Journal of Energy Engineering
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    • v.20 no.2
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    • pp.103-108
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    • 2011
  • $Li_2MnSiO_4$/C was synthesized by solid state reaction and solution synthesis with sucrose for carbon source. The X-ray diffraction patterns of solid state reaction indicates small amount of impurities. By FE-SEM and HR-TEM, solution synthesis comprised several tens of nanometer comparing to 500~600 nm of $Li_2MnSiO_4$/C prepared by solid state reaction. The $Li_2MnSiO_4$/C prepared by solution synthesis show better electrochemical performance than solid state reaction. The first charge-discharge capacity are 236, 189 mAh/g respectively by solution synthesis. But its cycle performance was poor as yet and its capacity retention was 62% after 10 cycles.

A Study on the Retailer's Global Expansion Strategy and Supply Chain Management : Focus on the Metro Group (소매업체의 글로벌 확장전략과 공급사슬관리에 관한 연구: 메트로 그룹을 중심으로)

  • Kim, Dong-Yun;Moon, Mi-Jin;Lee, Sang-Youn
    • Journal of Distribution Science
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    • v.11 no.12
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    • pp.25-37
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    • 2013
  • Purpose - The structure of retailing has changed as retailers develop markets in response to business environment changes. This study aims to analyze the general situation of retailers in order to predict future global strategy using case studies of overseas expansion strategy and the Metro Group's global strategy. Research design, data, and methodology - The backgrounds to the new retail business model and retailer classification are analyzed as theoretical data. In addition, the key success point of the Metro Group's "cash and carry" strategy is analyzed as is the Metro Group's global CFAR (collaborative planning, forecasting, and replenishment) strategy. Finally, the plan for cooperation and precise forecasting under the Metro Group's supply chain management are analyzed from the promotion environment viewpoint. Related materials analyzed included the 2012 annual report, the Metro Group's web page, and a video interview with the executive in charge of global strategy and the new market development department. Some data were revised to avoid disrupting essential aspects of the case studies. Results - The important finding was that the Metro Group could be a world-class retail company with its successful global expansion strategy. The Metro Group's global strategy's primary goal is to have a leading business position in Eastern and Western Europe. The "cash and carry" strategy is highest priority in its overseas expansion strategy. Moreover, the Metro Group has standardized product planning capacity, which could be applied in various countries with different structural and cultural backgrounds. This is the main reason that the Metro Group could rapidly become successful in the Eastern Europe and Asian markets through its structural overseas expansion strategies. In addition, the Metro Group emphasizes the importance of supply chain management. Conclusions - First, retailers should create additional value through utilizing the domestic market, market power, and economies of scale to launch a global strategy to maximize benefits from diversification. Second, the political, economic, and cultural background of the target country needs to be understood to successfully implement the overseas expansion strategy. Third, the main factor of successful cooperation with a local partner is how quickly the company gains total understanding of the business resources and core competence of its partner. All organizations should focus on the achievement of goals in order to successfully operate the partnership. Fourth, retailers should improve their business, financial and organizational structure. Moreover, the work processes and company culture should also be improved to respond strongly in the competitive global market. Fifth, the essential point of a successful retail business is the control capacity of its branding and format. The retailer could avoid forecasting errors through supply chain management by perfectly distributing the actual amount of its inventory. In addition, the risks along the supply chain are effectively shared between the supply chain partners. Finally, the central tendency of the market is to gain in strength with this taking place across all parts of the business.

Performance Evaluation of Hazardous Substances using Measurement Vehicle of Field Mode through Emergency Response of Chemical Incidents

  • Lee, Yeon-Hee;Hwang, Seung-Ryul;Kim, Jae-Young;Kim, Kyun;Kwak, Ji Hyun;Kim, Min Sun;Park, Joong Don;Jeon, Junho;Kim, Ki Joon;Lee, Jin Hwan
    • Korean Journal of Environmental Agriculture
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    • v.34 no.4
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    • pp.294-302
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    • 2015
  • BACKGROUND: Chemical accidents have increased owing to chemical usage, human error and technical failures during the last decades. Many countries have organized supervisory authorities in charge of enforcing related rules and regulations to prevent chemical accidents. A very important part in chemical accidents has been coping with comprehensive first aid tool. Therefore, the present research has provided information with the initial applications concern to the rapid analysis of hazardous material using instruments in vehicle of field mode after chemical accidents. METHODS AND RESULTS: Mobile measurement vehicle was manufactured to obtain information regarding field assessments of chemical accidents. This vehicle was equipped with four instruments including gas chromatography with mass spectrometry (GC/MS), Fourier Transform Infrared Spectroscopy (FT-IR), Ion Chromatography (IC), and UV/Vis spectrometer (UV) to analyses of accident preparedness substances, volatile compounds, and organic gases. Moreover, this work was the first examined the evaluation of applicability for analysis instruments using 20 chemicals in various accident preparedness substances (GC/MS; 6 chemicals, FT-IR; 2 chemicals, IC; 11 chemicals, and UV; 1 chemical) and their calibration curves were obtained with high linearity ( r 2 > 0.991). Our results were observed the advantage of the high chromatographic peak capacity, fast analysis, and good sensitivity as well as resolution. CONCLUSION: When chemical accidents are occurred, the posted measurement vehicle may be utilized as tool an effective for qualitative and quantitative information in the scene of an accident owing to the rapid analysis of hazardous material.

Relationship between Relevance Index and Hospital Management Performance (지역 의료이용 친화도(RI)와 병원 경영성과의 관계)

  • Park, Jong Young;Lee, Jin Woo
    • Journal of Digital Convergence
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    • v.17 no.3
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    • pp.261-269
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    • 2019
  • The purpose of this study is to present the effective management strategy of RI based on the results of research on the causal relationship between the regional medical care capacity and the hospital management performance by calculating the RI of the general hospitals in Korea, This research has significance. The results of this study are as follows: First, statistically significant differences were found in Number of beds and recurring profits in urban areas by the general characteristics. Second, the correlations between the RI and the variables of the regional medical use are as follows: Recurring profit ratio, New Outpatient Visits, Operating Margin, Daily Outpatient Visits per 100 Beds, Daily Inpatient Days per 100 Beds, and Average Charge per Inpatient Day. Based on the results of this study, the significance of this study is as follows. First, we calculated the affinity for local medical use, which is the index of local medical utilization. Secondly, it is analyzed according to internal and external environmental factors such as city size, hospital size, etc. It can be said that the hospital provided basic data for establishment of hospital management strategy to increase the utilization rate of local medical care.

Study on economic effects of outsourcing of food materials on the hotel kitchen - Focus on cooking Western food in the first class hotel - (식재료 아웃소싱이 경제적 주방에 미치는 영향에 관한 연구 - 특1급호텔 양식조리를 중심으로 -)

  • 성태종
    • Journal of Applied Tourism Food and Beverage Management and Research
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    • v.13 no.2
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    • pp.45-69
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    • 2002
  • This study is designed to examine feasibility and limitation of outsourcing in cooking Western food in a hotel, to interpret importance of outsourcing(eg. outside order, outside procurement, outside supply) in a broad sense in order to reinforce the core capacity in the cooking department, and to know whether the cooking human power is efficiently used and how much the chefs recognize outsourcing of food materials. As many companies conduct restructuring to cut down its size, the reduction of human power led the Western food cooking in the hotel to lower core capacities, lower quality, and lower efficiency. In addition, the sagging morale of chefs undermined creativity. To change from the traditional kitchen to an economic kitchen needs to look into importance of outsourcing, cognitive attitude of chefs, relation with outside suppliers. Here suggests performance of positive changes in the structure The study examined feasibility and limitation of outsourcing in the hotel kitchen as well as chefs' cognitive attitude toward outsourcing of food materials to reinforce core capabilities of the hotel kitchen. 1. Companies of outsourcing are selected according to variability of price conditions, flexibility of contract conditions, popularity of the outsourcing company, and reputation of the outsourcing company. 2. The importance of outsourcing in the Western food cooking is divided into 4 factors such as standard of selecting outsourcing companies, policies of cooking manu, quality of cooking, and quantity of cooking. 3. The most feasible section in outsourcing of food materials is a process of kneading flour for bread, which shows that many Western-food chefs expect to put higher possibility of outsourcing on the kneading. In other words, when it comes to confectionery and bakery, there are many outside expert processing companies supplying high quality products. In the order of outsourcing feasibility, sauce is followed by processed vegetable, garnish of main dish, and soup. The least feasible section in outsourcing of food materials is appetize. Appetize includes a concept of a improvised dish and needs speed. Due to its color, freshness, and sensibility of taste, the appetize plays a key role in the Western food cooking. 4. When outsourcing is taken in place, the highest risk is to lower the inner cooking skills. Therefore chefs in charge of the Western food sequently recognize both internal problems including storage of cooking skills, unstability of layoffs, and loss of cooperation between departments, and external problems including inferior goods, difficulty of differentiating manu, delay of delivery, and expiration date. It shows that most of the Western food chefs consider risks of the internal problems at first. 5. A effective outsourcing needs appropriate selection of outsourcing companies, maintenance of credibility, active communication, check and management of hygiene. However regardless of their position or career, chefs in charge of the Western food have the same cognitive attitude toward selecting successful outsourcing companies after the outsourcing system is enforced. The core of cooking, or a final stage in the full process of so-called artistic cooking, should be treated with insourcing. Reduction of several cooking processes resulted in shortened cooking time, increased efficiency, faster cooking, cutting the waiting-lines, and finally more room for customers. The outsourcing system can reduce or eliminate the following processes in cooking: buying various food materials, checking, storing, preparing, and processing. Especially in the Western food cooking department of a hotel, the outsourcing system should be enforced to make an economic kitchen and to efficiently manage it. Wow it's time to change from the traditional kitchen to an economic kitchen in the hotel cooking department. For that, the cooking department should become a small but strong organization by outsourcing except its core work.

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Curriculum Development for the Department of Marine Products Marketing in Fisheries High Schools (수산계 고등학교 수산물유통과 교육과정 개발)

  • Kim, Sam-Kon;Shin, Jin-Han
    • Journal of Fisheries and Marine Sciences Education
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    • v.13 no.1
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    • pp.1-18
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    • 2001
  • The purpose of this research was to develop curricula for the department of marine products marketing in fisheries high schools. The specific objectives were as follows; 1) To investigate the demand of students, teachers in fisheries high schools, and workers in marine products marketing for the educational program. 2) To analyze the jobs of the marine products marketing fields. 3) To develop curricula for the department of marine products marketing on the basis of the theoretical background and the result of the objective 1) and 2). In order to achieve these objectives, domestic and foreign literatures, research reports, and theses were referred to in order to know the academic classification of fisheries economics and curricula of junior colleges and universities were collected and analyzed. To achieve the first objective, the degree of the students' knowledge of marine products marketing through fisheries management textbook was investigated. And the questionnaire survey of the demand was conducted on the subject of professors at the departments of fisheries management, teachers in the charge of the related courses and those who work for marine products marketing-related firms. The questionnaire was composed of 22 items about the knowledge of marine products marketing and 27 items about the job capacity. To achieve the second objective, the occupations were surveyed on the subjects of the works who work for marine products marketing. They were sampled randomly among the marine products buyers, wholesalers, auctioneers and salespersons. The results of this research were as follows; Taking grades and credits at each subject were made out on the consultation of the experts in marine products marketing. The curriculum of the professional subjects related to marine products marketing in fisheries high schools is suggested as follows; General Fisheries(10th grade, 6 credits, curricular discretionary class), General Oceanography(10th grade, 4 credits, curricular discretionary class), Fisheries Marine Transportation Information(11th grade, 8-12 credits), Marine Products Marketing(11th grade, 8-12 credits), Fishery Sale and Management(11th grade, 8-12 credits), General Fisheries Management(11th grade, 6-8 credits), Accounting Principle(11th grade, 4-6 credits), Marine Products Processing(12th grade, 4-8 credits), Commercial Law(12th grade, 4-6 credits), Management Practice(12th grade, 4-6 credits), Computer Practical Business(12th grade, 4-6 credits), Marketing(12th grade, 4-8 credits), General Marketing Management(12th grade, 6-8 credits), Marketing Information Practical Business(12th grade, 4-6 credits) Marketing Management I(12th grade, 4-6 credits), Marketing Management II(12th grade, 4-6 credits). If this curriculum is adopted, it will meet the demands of the educational aims and the industrial society.

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