A Reliability Evaluation Model for the Power Devices Used in Power Converter Systems Considering the Effect of the Different Time Scales of the Wind Speed Profile

Haiting Ji,Hui Li,Yang Li,Li Yang,Guoping Lei,Hongwei Xiao,Jie Zhao,Lefeng Shi 전력전자학회 2016 JOURNAL OF POWER ELECTRONICS Vol.16 No.2

This paper presents a reliability assessment model for the power semiconductors used in wind turbine power converters. In this study, the thermal loadings at different timescales of wind speed are considered. First, in order to address the influence of long-term thermal cycling caused by variations in wind speed, the power converter operation state is partitioned into different phases in terms of average wind speed and wind turbulence. Therefore, the contributions can be considered separately. Then, in regards to the reliability assessment caused by short-term thermal cycling, the wind profile is converted to a wind speed distribution, and the contribution of different wind speeds to the final failure rate is accumulated. Finally, the reliability of an actual power converter semiconductor for a 2.5 MW wind turbine is assessed, and the failure rates induced by different timescale thermal behavior patterns are compared. The effects of various parameters such as cut-in, rated, cut-out wind speed on the failure rate of power devices are also analyzed based on the proposed model.

BOCNDARY INTEGRAL SOLUTIONS OF SOUND SCATTERING BY A TARGET IN HALF INFINITE SPACE

Xu Haiting 한국소음진동공학회 1994 한국소음진동공학회 국제학술대회논문집 Vol.1994 No.3

How does Freshippo subvert the traditional fresh food industry?

Xiru PAN,Haiting Wang,Man Hin Chan,Yuhe ZUO Academy of Asian Business (AAB) 2020 Academy of Asian Business Review Vol.6 No.2

This case study aims to analyze the development story of Freshippo, also named as Hema Fresh. It is an outstanding Chinese retail company owned by Alibaba and best known for its innovative new retail model driven by big data and advanced technology. The report is presented in four parts. Firstly, a detailed brand analysis of this newborn retail platform is conducted through market segmentation, positioning, and marketing strategies to present a clear band image of Freshippo. Then, the development timeline and three turning points during Freshippo’s expansion are highlighted. This part mainly focuses on how Freshippo designs and updates its business model to adapt to different market conditions. The third part looks into the success factors behind Freshippo’s achievement, including how it revolutes traditional retail models and maintains smooth development during the crisis. And based on the analysis of Freshippo’s current position, four challenges are put forward from internal and external aspects, followed by the recommended solutions. Finally, the valuable lessons of Freshippo’s success will be covered as the conclusion.

Anti-inflammatory and analgesic activities of the hydrolyzed sasanquasaponins from the defatted seeds of Camellia oleifera

Yong Ye,Haiting Xing,Xuelan Chen 대한약학회 2013 Archives of Pharmacal Research Vol.36 No.8

The defatted seeds of Camellia oleifera (Abel.)are used for stopping itching and pain in old days, theeffective compounds need to be investigated. Sasanquasaponinas a rich fraction was extracted with 70 % ethanol,purified by AB-8 macro-reticular resin, crystallized in 80 %ethanol, and further hydrolyzed by 4 % hydroxyl potassiumor 2 M hydrochloride. Anti-inflammatory activities of theextracts were measured by carrageenan-induced paw edemain rats and croton oil induced ear inflammation in mice; theanalgesic activities were analyzed by hot plate test, aceticacid induced writhing in mice; the levels of pain mediatorsof IL-1b, TNF-a and PGE2 were determined; the antioxidativeactivities in vivo were evaluated by MDA, SOD andGSH-Px in serum of rats. The extracts showed significant(p\0.01) anti-inflammatory and analgesic activities,remarkably (p\0.01) inhibited production of pro-inflammatorycytokines and PGE2, decreased MDA and increasedSOD and GSH-Px in serum. Inhibition of IL-1b, TNF-a andPGE2 may contribute to their anti-inflammatory and analgesiceffects; elimination of free radicals is also involved. The sapogenin and acid hydrolyzed product have betteranti-inflammatory, analgesic effects, and stronger antioxidativeactivity than sasanquasaponin and alkaline hydrolyzedproduct, and they are better candidate medicines forinflammation and pain.

Greenhouse Gas Emissions Trading Schemes : Recent Developments and Policy Recommendations for Korea

Yong Gun KIM,Erik F,HAITES 한국환경정책평가연구원 2005 한국환경정책평가연구원 연구보고서 Vol.2005/re-02 No.-

국제 배출권 거래, 청정개발체제(Clean Development Mechanism: CMD), 공동이행 등 3대 교토 메커니즘, 유럽연합(EU)의 배출권 거래제, 영국, 일본, 호주의 배출권 거래제, 그리고 미국과 캐나다에서 추진중인 배출권 거래제 등 전세계적으로 다양한 온실가스 배출권 거래제도가 시행되었거나 추진되고 있다. 온실가스 배출권 거래제도는 기후변화 대응을 위한 정책적 노력에서 점차 핵심적인 수단으로 자리잡고 있으며, 특히 EU 배출권 거래와 CDM은 광범위한 분야에서 기후친화적인 투자를 촉진하는데 의미있는 역할을 하고 있는 것으로 평가된다. 하지만 온실가스 배출권 거래제도는 초기 할당에 관련된 형평성 문제, 다양한 제도간의 연계, 기존 환경정책수단과의 조화 등 여전히 해결해야 할 많은 어려운 문제들을 안고 있다. 본 연구는 현재 전세계적으로 진행중인 온실가스 배출권 거래제도에 대한 분석 및 비판적 평가와 함께 우리나라의 온실가스 배출권 거래제도 도입방향에 대한 시사점을 제시하고 있다. 특히 국제적인 온실가스 감축의무를 부담하고 있지 않는 상황을 고려할 때 우리나라는 자발적 참여방식(의무부담 이전단계)에서 출발하여 강제적 총량규제(의무부담 이후단계)로 이행하는 단계적 접근방식이 바람직하다고 판단된다. 의무부담 이전단계에서의 온실가스 배출권 거래제도는 CDM 사업과 연계하여 추진하는 것이 바람직하다. 제18차 CDM 집행이사회(2005. 2월) 및 제1차 교토의정서 당사국총회(2005. 12월) 결정에 따라 프로그램 형태의 개도국 단독(Unilateral) CDM이 허용되게 되었으며, 이에 따라 국내 온실가스 배출권 거래제를 통한 감축효과를 CDM 크레딧으로 인정받을 수 있다. 따라서 국내 배출권 거래제의 CDM 사업화를 통해 배출업소에 대한 거래제 참가 인센티브를 제공함과 동시에 국제 온실가스 감축노력에 기여하는 효과를 거둘 수 있다. 국제적 감축의무를 부담하게 될 경우 강제적 총량규제 및 배출권 거래제의 도입이 불가피할 것으로 전망되는데, 이 경우 초기 배출권은 경매를 통해 유상으로 배분하는 것이 바람직하다. 과거 배출량 등에 기초한 무상배분방식(Grandfathering)은 다배출업소에 과도한 보상을 하게 되는 결과를 초래함은 물론 신규 시설에 대한 차별, 소모적인 협상에 따른 시간과 자원의 낭비 등 다양한 문제점을 초래함으로 바람직하지 않다. 무엇보다 이러한 점을 악용하는 기업이 사전에 배출을 늘리고 오히려 자연발생적 감축효과에 대해 크레딧을 요구하는 폐해가 우려된다. 따라서 정부 차원에서 미래의 배출권 할당시 오염자 부담원칙에 충실한 경매제도의 적용의지를 가급적 조기에 천명하는 것이 불필요한 사회적 갈등을 해소하는 데 바람직하다고 판단된다. 또한 2007년 시행예정인 수도권 대기오염물질 배출권 거래제도와 온실가스 배출권 거래를 연계하여 실시할 경우 추가적인 행정비용과 중복규제를 최소화하면서 정부와 기업 모두의 효율성을 극대화할 수 있을 것으로 판단된다. 단, 수도권에 국한하여 배출권 거래제를 시행할 경우 수도권 이외 지역으로의 배출량 누출(Leakage effect)을 예방하기 위해 원단위 기준(원단위 감소시에만 배출권 판매 허용)을 병행하여 적용할 필요가 있다. 또한 온실가스 배출권 거래제도의 도입 기반 확충을 위해 기업 온실가스 배출량 보고 및 공개제도를 먼저 도입하는 것이 바람직하다고 판단된다. This study reviews and evaluates various GHG emissions trading schemes, including the Kyoto mechanisms, EU emissions trading scheme (ETS), United Kingdom ETS, the New South Wales trading scheme in Australia, and the ETS plans in Canada and the United States. Existing schemes, including CDM and EU ETS, show significant impacts on decision making in a wide range of areas to promote climate friendly investments and operations. In spite of the huge uncertainty of future climate policy, emissions trading is likely to play a major role. The experience and performance of GHG emissions trading in the past, however, reveals a lot of problems and challenges, including equity and efficiency issues related to initial allowance allocations, harmonization and the coordination of regional/national schemes, and the role of CDM in the global trading market. Based on a review and analysis of existing GHG emissions trading mechanisms, this study recommends a framework for GHG emissions trading in Korea. A phased approach is required to meet the unique policy environment of Korea: A voluntary emissions trading scheme in the pre-commitment stage, and a mandatory cap-and-trade scheme in the commitment stage. For a mandatory GHG cap-and-trade scheme, the best way to allocate allowances seems to be an auction combined with revenue recycling to the participants. An auction avoids a lot of potential problems including baseline protection, compensation for early action, adverse selection, windfall profits to incumbents, entry barriers, negotiation complexity and many other equity and efficiency issues. In the pre-commitment stage, CDM can be utilized as a key driving force for developing countries to introduce a GHG emissions trading scheme. An incentive auction can be proposed as a potential CDM project. Considering the existing air pollutant cap-and-trade policy of Korea, a multi-pollutant cap-and-trade system, covering GHG and conventional air pollutants, for the Seoul Metropolitan Area may be a promising option for cost-effective GHG emissions trading in Korea. Such a multi-pollutant trading scheme also can be applied for a unilateral policy-based CDM. The regulation on mandatory reporting and disclosure of corporate GHG emissions is also a useful initial step towards successful implementation of emissions trading. Several policy implications are also suggested for the future development of emissions trading for conventional air pollutants in Korea, which is planned to start in 2007.

Leaching of rare earth metals (REMs) from Korean monazite concentrate

Panda, R.,Kumari, A.,Jha, M.K.,Hait, J.,Kumar, V.,Rajesh Kumar, J.,Lee, J.Y. Korean Society of Industrial and Engineering Chemi 2014 Journal of industrial and engineering chemistry Vol.20 No.4

Systematic scientific studies for dephosphorization and acid leaching of Korean monazite are reported here. 50% NaOH (w/v) solubilizes 99.99% phosphate, at 170<SUP>o</SUP>C, 100g/L pulp density in 4h. Kinetics of phosphate leaching fitted well with model ''chemical reaction control,'' i.e. 1-(1-X)<SUP>½</SUP>=k<SUB>c</SUB>t, E<SUB>a</SUB>=58.04kJ/mol. Further, rare earth hydroxides (REHs) was leached using 6N HCl at 90<SUP>o</SUP>C, 60g/L pulp density for 2h to recover ~95% REMs. Leach liquor generated can be further processed using solvent extraction/ion exchange techniques. From the pure solutions, metal/salts could be obtained using evaporation, precipitation, etc.

Domestic Greenhouse Gas Emissions Trading Schemes

( Yong Gun Kim ),( Erik F. Haites ),( Steve Sorrell ),( Tae Yong Jung ),( Poul Erik Morthorst ),( Myung Kyoon Lee ),( Jong Soo Lim ) 한국환경연구원 2003 수시연구보고서 Vol.2003 No.-

선진국에 대한 양적 감축의무 부과와 국제 배출권 거래제도의 도입을 핵심 내용으로 하는 교토의정서의 채택은 국제 온실가스 배출권 거래시장의 출범을 예고하고 있으며, 각국 정부는 이에 대응하기 위한 국내정책기반을 강화하고 있다. 덴마크와 영국 등 일부 선진국은 이미 국가 차원의 온실가스 배출권 거래제도를 시행하고 있으며, 유럽연합은 2005 년부터 역내 모든 국가가 참여하는 강제적인 온실가스 배출권 거래제도의 도입을 결정한 바 있다. 일본, 캐나다 등 비유럽 선진국에서도 온실가스 배출권 거래제의 도입을 적극 추진중이며, 교토의정서 참여를 거부하고 있는 미국에서도 주정부와 민간기업의 자율적인 배출권 거래제 도입이 확산되고 있으며 특히 미국 의회는 강제적인 감축목표 설정과 전국적인 배출권 거래제도의 도입을 전통적인 대기관리정책과 연계하여 추진하고 있다. 본 연구는 교토의정서에 명시되어 있는 국제 온실가스 배출권 거래제도와 함께 상호 호환거래가 가능한 청정개발체제 및 공동이행 사업의 크레딧 거래와 관련하여 최근까지의 협상결과를 분석하였다. 그리고 전국적인 온실가스 배출권 거래제도를 시행하고 있는 영국의 사례의 특징과 시사점을 분석하였으며, 2005 년부터 시행예정인 유럽연합의 역내 배출권 거래제도에 대해서도 지금까지의 진행경과와 향후 전망을 분석하였다. 또한 온실가스 배출권 거래제도와 밀접하게 연계되어 진행되고 있는 신재생에너지 발전크레딧 제도의 사례로서 덴마크의 최근 관련 동향을 정리하였다. 뿐만 아니라 미국, 일본, 캐나다의 온실가스 배출권 거래제도 도입 추진동향을 분석하고 향후 전망과 시사점을 도출하였다. 이들 비유럽 국가들은 유럽의 역내 온실가스 배출권 시장과의 연계를 모색하고 있으며, 향후 통합된 국제 배출권 시장으로 발전할 가능성이 높은 것으로 평가된다. 우리나라는 기후변화협약 및 교토의정서상으로 아직 개도국 지위를 인정받고 있음에 따라 정량적인 감축의무를 부담하고 있지 않다. 하지만 선발 개도국으로서 향후 추가적인 온실가스 감축의무 협상시 의무부담국가에 포함될 가능성이 있고, 국제적인 배출권 시장의 확대 과정에서 국내 대응역량의 확충이 필요한 상황이다. 본 연구에서는 이와 같은 특수한 여건하에서 국내적인 온실가스 배출권 시장의 설계에 대한 기본원칙과 세부 설계방안에 대한 분석을 시도하였다. 강제적인 배출권 거래제도의 도입 이전단계에서 자발적인 인센티브에 기초한 배출권 시장의 조성이 필요할 것으로 판단된다. 배출권 거래제도의 도입을 위한 국제적인 노력은 보다 활성화될 것으로 예상되며, 이에 대한 동향분석과 국제적인 협력방안에 대한 연구 또한 지속적으로 확대되어야 할 것이다. 본 연구는 이러한 연구의 시발점으로 평가되며, 앞으로도 각국의 전문가가 참여하는 국제협력연구가 적극 추진되어야 할 것이라 판단된다. The Kyoto Protocol, if it enters into force, would establish emission limitation commitments for the developed countries and a full international emissions trading system for greenhouse gases. This has forced each nation to give the emissions trading consideration and prepare its domestic climate policies. Domestic greenhouse gas (GHG) emissions trading systems (ETS) are already being in operation in UK and Denmark, and European Union has decided to introduce compulsory domestic GHG emissions trading from year 2005. Other non-European developed countries such as Japan and Canada are actively considering the introduction of domestic ETS. In the United States, even though it is still refusing to ratify the Protocol, many states are implementing or considering programs that would limit GHG emissions and a growing number of major companies are undertaking significant efforts to address climate change including participating in emissions trading. The United States Congress tries to establish the compulsory reduction target and a nation-wide ETS combined with its traditional climate policy. This study analyzed the results of recent international climate change negotiations related to the credit transaction of Clean Development Mechanism and Joint Implementation, and the international GHG ETS which was stated in the Kyoto Protocol. This study also provides an overview of the UK emissions trading scheme, describing its main elements and limitations and difficulties associated with the scheme. The major elements of the EU Emissions Trading Scheme, which begins in 2005, are also reviewed focusing on the areas which have generated particular controversy and difficulty. Also, the recent trend in Denmark is summarized especially in relation to the energy reform and the green certificate markets. The current progresses in introducing GHG ETS are overviewed for United States, Japan and Canada. These non-European countries are considering the linkage with the EU emissions trading market and it is assessed that the expansion to the integrated international ET market is highly likely. Korea, as a developing country under UNFCCC and Kyoto Protocol does not have the obligation to reduce its GHG emissions. However, it is likely that the country could be obligated to take more responsibilities, depending upon the future negotiations. Thus, it needs to prepare its domestic climate change policies for the future expansion of international ET market. In this study we tried to analyze the basic principles for the design of domestic GHG ETS and detailed design method under these special circumstances. And it appears that it is necessary to promote a voluntary and incentive based ET market prior to the introduction of compulsory ETS. The international effort to introduce ETS is expected to expand and intensify, thus the trend analysis and researches on international cooperation program should be continuously pursued. This study is the start of those research activities and it is believed that international cooperative researches of various experts of each nation are indispensable in this regard.

Construction of Recombinant Pichia pastoris Carrying a Constitutive AvBD9 Gene and Analysis of Its Activity

( Jian Tu ),( Kezong Qi ),( Ting Xue ),( Haiting Wei ),( Yongzheng Zhang ),( Yanli Wu ),( Xiuhong Zhou ),( Xiaolong Lv ) 한국미생물 · 생명공학회 2015 Journal of microbiology and biotechnology Vol.25 No.12

Avian beta-defensin 9 (AvBD9) is a small cationic peptide consisting of 41 amino acids that plays a crucial rule in innate immunity and acquired immunity in chickens. Owing to its wide antibacterial spectrum, lack of a residue, and failure to induce bacterial drug resistance, AvBD9 is expected to become a substitute for conventional antibiotics in the livestock and poultry industries. Using the preferred codon of Pichia pastoris, the mature AvBD9 peptide was designed and synthesized, based on the sequence from GenBank. The P. pastoris constitutive expression vector pGHKα was used to construct a pGHKα-AvBD9 recombinant plasmid. Restriction enzyme digestion was performed using SacI and BglII to remove the ampicillin resistance gene, and the plasmid was electrotransformed into P. pastoris GS115. High-expression strains with G418 resistance were screened, and the culture supernatant was analyzed by Tricine-SDS-PAGE and western blot assay to identify target bands of about 6 kDa. A concentrate of the supernatant containing AvBD9 was used for determination of antimicrobial activity. The supernatant concentrate was effective against Escherichia coli, Salmonella paratyphi, Salmonella pullorum, Pseudomonas aeruginosa, Enterococcus faecalis, and Enterobacter cloacae. The fermentation product of P. pastoris carrying the recombinant AvBD9 plasmid was adjusted to 1.0 × 108 CFU/ml and added to the drinking water of white feather broilers at different concentrations. The daily average weight gain and immune organ indices in broilers older than 7 days were significantly improved by the AvBD9 treatment.

Hydrometallurgical recovery of copper from the leach liquor of waste PCBs

Kumari Suruchi,Panda Rekha,Bawkar Shilpa Kalamani,Hait Jhumki,Yoo Kyoungkeun,Prasad Ranjit,Jha Manis Kumar 한국자원공학회 2024 Geosystem engineering Vol.27 No.2

The present work is focused on the recovery of pure copper metal from leach liquor of discarded printed circuit boards (PCBs) using solvent extraction and electrowinning techniques. Leach liquor containing copper was produced from PCBs of scrap computers using pretreatment followed by the leaching technique. The obtained leach liquor contained 19.35 g/L of copper and 6 M concentration of nitric media. From the obtained leach liquor, systematic solvent extraction and electrowinning studies were carried out for maximum extraction of copper, leaving other metals to be present as impurities. Various process parameters of solvent extraction viz. effect of pH, contact time, phase ratio, and so on were studied and optimized. McCabe–Thiele diagram was plotted, which shows that complete recovery of copper can be achieved in three stages using 40% LIX 84IC and O/A ratio 1/1 at equilibrium pH 2.2 in a mixing time of 20 min. The loaded copper was stripped using 10% H2SO4. The obtained strip solution containing 19.35 g/L Cu was electrowinned at the optimized condition, i.e., 8 hours’ time and 205 A/m2 cathode density with 99.99% current efficiency. 99.8% pure copper metal was obtained. The developed process is environmentally sustainable and has potential to be commercialized after scale-up studies.

Leaching of rare earth metals (REMs) from Korean monazite concentrate

Rekha Panda,Manis Kumar Jha,이진영,Archana Kumari,Jhumki Hait,Vinay Kumar,J. Rajesh Kumar 한국공업화학회 2014 Journal of Industrial and Engineering Chemistry Vol.20 No.4

Systematic scientific studies for dephosphorization and acid leaching of Korean monazite are reported here. 50% NaOH (w/v) solubilizes 99.99% phosphate, at 170 ℃, 100 g/L pulp density in 4 h. Kinetics of phosphate leaching fitted well with model ‘‘chemical reaction control,’’ i.e. 1 - (1 - X)1/2 = kct, Ea = 58.04 kJ/mol. Further, rare earth hydroxides (REHs) was leached using 6 N HCl at 90 ℃, 60 g/L pulp density for 2 h to recover ~95% REMs. Leach liquor generated can be further processed using solvent extraction/ion exchange techniques. From the pure solutions, metal/salts could be obtained using evaporation, precipitation, etc.