• Title/Summary/Keyword: gradual increasing

Search Result 242, Processing Time 0.024 seconds

Advances in High Efficiency Back Contact Back Junction Solar Cells

  • Balaji, Nagarajan;Park, Cheolmin;Raja, Jayapal;Yi, Junsin
    • Current Photovoltaic Research
    • /
    • v.3 no.2
    • /
    • pp.45-49
    • /
    • 2015
  • In the past few decade's researchers, scientists, engineers of photovoltaic (PV) industry are working towards low cost high efficiency Si solar cells. Over the last decade the interest in back contact solar cell has been acquiring as well as a gradual introduction to industrial applications is increasing. As an alternative to conventional solar cells with a front and rear contact, the back-contact cells has remained a research topic. The aim of this work is to present a comprehensive summary of results incurred in the back contact back junction solar cells such as interdigitated back-contact (IBC), emitter wrap-through (EWT) and metallization wrap-through (MWT) over the years.

Effect of aggregate type on heated self-compacting concrete

  • Fathi, Hamoon;Lameie, Tina
    • Computers and Concrete
    • /
    • v.19 no.1
    • /
    • pp.33-39
    • /
    • 2017
  • In this study, two types of aggregate were used for making self-compacting concrete. Standard cubic specimens were exposed to different temperatures. Seventy-two standard cylindrical specimens ($150{\times}300mm$) and Seventy-two cubic specimens (150 mm) were tested. Compressive strengths of the manufactured specimens at $23^{\circ}C$ were about 33 MPa to 40 MPa. The variable parameters among the self-compacting concrete specimens were of sand stone type. The specimens were exposed to 23, 100, 200, 400, 600, and $800^{\circ}C$ and their mechanical specifications were controlled. The heated specimens were subjected to the unconfined compression test with a quasi-static loading rate. The corresponding stress-strain curves and modulus of elasticity were compared. The results showed that, at higher temperatures, Scoria aggregate showed less sensitivity than ordinary aggregate. The concrete made with Scoria aggregate exhibited less strain. The heated self-compacting concrete had similar slopes before and after the peak. In fact, increasing heat produced gradual symmetrical stress-strain diagram span.

Investigation on Behavior of HAN-based Propellant Droplet at High Temperature (고온에서 HAN 계열 추진제 액적의 거동에 대한 연구)

  • Hwang, Chang Hwan;Baek, Seung Wook;Han, Cho Young;Kim, Su Kyum;Jeon, Hyung Yeol
    • 한국연소학회:학술대회논문집
    • /
    • 2012.11a
    • /
    • pp.329-332
    • /
    • 2012
  • The droplet behavior of 83.9 wt.% HAN water solution was investigated experimentally with various ambient temperature and nitrogen environment. At the initial stage of evaporation under thermal decomposition temperature of HAN, gradual decreasing of droplet diameter was observed. After that, the droplet started to expand due to the internal pressure build up by water nucleation inside the droplet. The micro explosion was observed at higher temperature than the decomposition temperature of HAN and the remaining droplet showed similar behavior of single composition droplet. The decreasing rate was augmented as the ambient temperature increasing.

  • PDF

Running Characteristics for On-Line Test of Railway Vehicle

  • Han, Young-Jae;Kim, Seog-Won;Seo, Sung-Il;Mok, Jin-Yong;Lee, Su-Gil;Kim, Young-Mo
    • 제어로봇시스템학회:학술대회논문집
    • /
    • 2005.06a
    • /
    • pp.1347-1350
    • /
    • 2005
  • Recently, as the road capacity reaches a limit and environmental problems become serious, there exists a gradual increasing need for railway vehicles that are environment-friendly, punctual, reliable and safe. Accordingly, in addition to conventional railroad vehicles, lots of vehicles are being newly developed. Using the developed installed measurement system, the performance characteristics of railway vehicle could be monitored precisely. After recording the input real time data of each signal from railway vehicle to the network line, we could acquire the needed information through post processing program. We could verify the running performances of railway vehicle using this system. As a result, many latent defects have been found and corrected in the prototype train. The measurement systems have contributed to dramatic reduction of the developing period.

  • PDF

A Study on the Improvement of Export Risk Management in the Changing of Export Payment Methods (무역결제방식의 변화에 따른 수출보험제도의 개선방안에 관한 연구)

  • Kim, Byung-Hak;Gil-Jong, Hong
    • International Commerce and Information Review
    • /
    • v.8 no.3
    • /
    • pp.99-119
    • /
    • 2006
  • The recent trend in the payment terms of international trade shows the gradual shift toward more diversified payment methods (from L/C to not L/C) in order to cope with the increasingly dynamic international transactions in a more flexible manner. The reasons behind this recent shift are as follows : first, the global trade market is breaking away from the traditional L/C methods based on letters of credit toward a not L/C methods. nother reason for the changing trade payment methods is the increasing volume of intra transactions between headquarters and their foreign subsidiaries based on collection payment methods. Having mentioned the above problems that impede the Korean export insurance system, some suggestions can be put forward through a comparative analysis with foreign export insurance system. First, inducing private investments is one way of strengthening financial health of the KEIC. The KEIC also needs to diversify its insurance coverage adapting to the changing international trade environments.

  • PDF

Kinetics and Mechanism of the Anilinolysis of Diethyl Thiophosphinic Chloride in Acetonitrile

  • Hoque, Md. Ehtesham Ul;Lee, Hai-Whang
    • Bulletin of the Korean Chemical Society
    • /
    • v.32 no.7
    • /
    • pp.2306-2310
    • /
    • 2011
  • The nucleophilic substitution reactions of diethyl thiophosphinic chloride with substituted anilines ($XC_6H_4NH_2$) and deuterated anilines ($XC_6H_4ND_2$) are investigated kinetically in acetonitrile at 55.0 $^{\circ}C$. The values of deuterium kinetic isotope effects (DKIEs; $k_H/k_D$) invariably increase from secondary inverse ($k_H/k_D$ < 1) to primary normal (kH/kD > 1) as the nucleophiles change from the strongly basic to weakly basic anilines. The secondary inverse with the strongly basic anilines and primary normal DKIEs with the weakly basic anilines are rationalized by the gradual transition state (TS) variation from a predominant backside attack, via invariably increasing the fraction of a frontside attack, to a predominant frontside attack, in which the reaction mechanism is a concerted $S_N2$ pathway. A frontside attack involving a hydrogen bonded, four-center-type TS is substantiated by the primary normal DKIEs.

The Visual Display of Temporal Information for E-Textbook: Incorporating the Mind-mapped Timeline Authoring Tool

  • Lee, HeeJeong;Alvin Yau, Kok-Lim
    • KSII Transactions on Internet and Information Systems (TIIS)
    • /
    • v.12 no.7
    • /
    • pp.3307-3321
    • /
    • 2018
  • With the ever-increasing queries related to temporal (or time-related) information, such as the product launching time, in search engine, most web pages will be augmented with such information in the future. Meanwhile, the gradual emergence of the use of electronic textbooks (or e-Textbooks), which enrich the traditional paper-based textbooks with multimedia contents such as interactive quizzes and multimedia-based simulations, has led us to infer that e-Textbooks will be blended with temporal information to support learning. The use of temporal information helps teachers and students to understand the level of prior knowledge required to study a topic, as well as the sequence of learning activities and related sub-topics, that best attains the educational goals. This paper presents a simple yet efficient tool called TimeMap, which is based on mind mapping, to create an e-Textbook called TimeBook that takes account of time-related curriculum and the ability of students to learn via collaboration.

Antioxidative and Antimicrobial Activities of Essential oil from Artemisia vulgaris

  • Bhatt Lok Ranjan;Lim Jin-A;Chai Kyu-Yun;Kang Jeong-Il;Oh Hong-Keun;Baek Seung-Hwa
    • Natural Product Sciences
    • /
    • v.12 no.4
    • /
    • pp.226-231
    • /
    • 2006
  • Artemisia vulgaris, one of the most religious plants in Nepal, is used in the treatment of various ailments. In this study, antioxidative activity of essential oil from A. vulgaris was evaluated, using different in vitro methods and antimicrobial activity by disc diffusion method against skin disease microorganisms such as Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus pyogenes, Candida albicans and Propionibacterium acnes. The essential oil exhibited a concentration-dependent antioxidant activity. It showed strong metal chelating activity with low reducing and antioxidant power. However, gradual increase in radical scavenging activity was obtained with increasing concentration and reaction time. It also possessed a broad spectrum of antimicrobial activity and notable susceptibility was observed against S. pyogenes and P. acnes.

Free radical scavenging activity and kinetic behavior of the Galgeuntang water extract

  • Shin, Jeong-Mi;Kim, Young-Ok;Baek, Seung-Hwa
    • Advances in Traditional Medicine
    • /
    • v.8 no.1
    • /
    • pp.32-38
    • /
    • 2008
  • Galgeuntang water extract exhibited a strong free radical scavenging activity and reducing power determination. However, a gradual increase in the free radical scavenging activity and reducing power determination was obtained with increasing concentrations. The highest radical scavenging activity was shown by the water extract from Galgeuntang (116.93 ${\mu}g$/mL) and the water extract from Cinnamonum cassia Presl. (95.01 ${\mu}g$/mL). These results of phenolic and flavonoid contents of the extracts indicated that the strong radical scavenging activity of the Cinnamonum cassia Presl. extract might be in part due to the phenolic compounds. The correlation coefficient between TPC and DPPH ($r^2$ = 0.9312), TFC and DPPH ($r^2$ = 0.9677), showed positive correlation among total phenolic/flavonoid contents and antioxidant activity. These results suggest that Galgeuntang has a potential antioxidant activity.

DYNAMIC ECONOMIC DISPATCH USING OBJECT-ORIENTED PROGRAMMING (객체지향기법을 적용한 동적경계부하배분)

  • Baek, Young-Sik;Kwon, Gyu-Jin
    • Proceedings of the KIEE Conference
    • /
    • 1996.07b
    • /
    • pp.790-792
    • /
    • 1996
  • According to increase in electric power demand, the increasing rate of peak load compared with that of base load grows larger every year. Thus this paper deals with the optimal dynamic dispatch problem due to power rate limits and spinning reserve with loss or without loss. The first is adjusting module for gradual change of generator power by Object-Oriented Programming. The latter is an efficient dispatch module for the consideration of reasonable spinning reserve requirements. The proposed algorithm has been shown efficiency in real power system with loss.

  • PDF