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Study on verification of various national standards regarding phthalate testing in industrial products (공산품 중 프탈레이트류 함유량 분석법에 관한 국내외 표준의 검증 연구)

  • Song, Moon-Hwan;Cho, Young-Dal;Choe, Eun-Kyung;Myoung, Young-Chan
    • Analytical Science and Technology
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    • v.25 no.3
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    • pp.178-189
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    • 2012
  • As phthalates classified as toxic to reproduction category 2 and endocrine disrupting chemicals were more strictly regulated as Substances of Very High Concern (SVHC) for authorization in under EU REACH and considered as priority substances in RoHS II, standardization of phthalate testing method is now being proposed in IEC 62321 of IEC TC 111 and the 2nd revision of KS M 1991 is also finished. In order to assist standardization activities related to phthalating testing, solvent extraction part of existing national standards were compared and verified. Recovery of DEHP (diethylhexyl phthalate) from PVC (polyvinyl chloride) by Soxhlet extraction increased in the order of methanol, toluene, dichloromethane and hexane from 46.9% to 95.3% as measured by GC-MS. Optimum extraction time was verified to be 6 hours using hexane. Recovery of DBP (dibutyl phthalate), BBP (butylbenzyl phthalate), and DEHP from different matrixes such as PVC, nitro cellulose, ABS (acrylonitrile butadiene styrene). and EPDM(ethylene propylene diene monomer) rubber were evaluated to be more than 90% up to 99%. The detection limits of phthalates in solvent extraction followed by GC-MS analysis were 0.08~0.3 ${\mu}g/mL$ in solution and 8~30 mg/Kg in polymeric samples. GC-MS analyses of phthalates were carried out using different solvent extraction based on the EN 14372, ASTM D 7083, Japanese test method (MHLW 0906-4) and KS M 1991, proving that equivalent recoveries ranging from 98%~99% were obtained. DBP and DEHP were detected in three consumer products such as a child toy, a power cable and manicure with the amount of 22~1,910 mg/kg.

Environmental Geophysical Survey of Abandoned Landfills for Contamination Evaluation: A Case Study (불량 매립지 오염평가를 위한 지구물리 탐사 사례연구)

  • Lee, Sung-Soon;Lee, Jin-Yong;Yoon, Hee-Sung;Lee, Kang-Kun;Kim, Chang-Gyun;Yu, Young-Chul
    • Journal of Korean Society of Environmental Engineers
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    • v.28 no.5
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    • pp.463-471
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    • 2006
  • Electrical resistivity surveys were conducted at areas of abandoned landfills in Cheonan and Wonju. Geology and extent of leachate migration around the landfills were evaluated with collected resistivity data by 2-D and 3-D resistivity inverse modeling. The Cheonan landfill is located above the paddy fields and the resistivity survey lines were crossed to examine possible pollution at the paddy fields by leakage of the landfill leachate. In Wonju, the landfill and the downgradient paddy fields are divided by a concrete barrier wall. At the bottom of the landfill, there is a leachate settlement system, which has not been in operation. To evaluate leachate leakage into the paddy fields, a total of 4 survey lines were used. According to the resistivity survey results, the landfill leachate in Cheonan appeared to be restricted only within the interior of the landfill, not to migrate into the subsurface of the paddy fields. These results are well consistent with electrical conductivity values of groundwaters obtained from a periodic analysis of water qualities. In Wonju, however, it was inferred that the leachate emanating from the landfill migrated beneath the abandoned leachate settlement system and the leachate would reach the downgradient paddy fields. Low resistivity area was observed in the old reservoir area and it appeared to be derived from convergence of groundwater flows from the surrounding valley and the moist wet land. In addition, groundwater flow into the paddy fields occurs beneath the old reservoir embankment at depths of $7{\sim}8m$. This paper reports details of the resistivity surveys for the uncontrolled landfills.

A Rational Design of Coin-type Lithium-metal Full Cell for Academic Research (차세대 리튬 금속 전지 연구 및 개발을 위한 코인형 전지의 효율적 설계)

  • Lee, Mingyu;Lee, Donghyun;Han, Jaewoong;Jeong, Jinoh;Choi, Hyunbin;Lee, Hyuntae;Lim, Minhong;Lee, Hongkyung
    • Journal of the Korean Electrochemical Society
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    • v.24 no.3
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    • pp.65-75
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    • 2021
  • Coin cell is a basic testing platform for battery research, discovering new materials and concepts, and contributing to fundamental research on next-generation batteries. Li metal batteries (LMBs) are promising since a high energy density (~500 Wh kg-1) is deliverable far beyond Li-ion. However, Li dendrite-triggered volume fluctuation and high surface cause severe deterioration of performance. Given that such drawbacks are strongly dependent on the cell parameters and structure, such as the amount of electrolyte, Li thickness, and internal pressure, reliable Li metal coin cell testing is challenging. For the LMB-specialized coin cell testing platform, this study suggests the optimal coin cell structure that secures performance and reproducibility of LMBs under stringent conditions, such as lean electrolyte, high mass loading of NMC cathode, and thinner Li use. By controlling the cathode/anode (C/A) area ratio closer to 1.0, the inactive space was minimized, mitigating the cell degradation. The quantification and imaging of inner cell pressure elucidated that the uniformity of the pressure is a crucial matter to improving performance reliability. The LMB coin cells exhibit better cycling retention and reproducibility under higher (0.6 MPa → 2.13 MPa) and uniform (standard deviation: 0.43 → 0.16) stack pressure through the changes in internal parts and introducing a flexible polymer (PDMS) film.

Cases and Significance of Inscriptions with Homophonic yet Misspelled Words on Buncheong Ware from the Early Joseon Dynasty: Buncheong Bowl with Inscription of "Naeja" ('내자(內子)'명(銘)으로 본 조선 전기 분청사기의 동음오자(同音誤字) 명문 사례와 의의)

  • Park, Jung-Min
    • MISULJARYO - National Museum of Korea Art Journal
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    • v.97
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    • pp.55-68
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    • 2020
  • The inscription found on buncheong ware (粉靑沙器, grayish-blue-powdered celadon) provides information on the bowl today, but in the past served as a device for controlling tributary payments (貢納) and the movement of government property (官物). The inscription had to be written or engraved clearly so that it could be recognizable to officials in charge of managing bowls. Such inscriptions offer important clues for contemporary research on buncheong ware. Buncheong Bowl with Stamped Design and Inscription of "Naeja" (內子) (bon 13808) in the collection of the National Museum of Korea bears a distinct inscription compared to other buncheong ware. Commonly, the inscription on buncheong indicated the name of the government office (官司名) to which the vessel belonged or the name of the place (地名) where the vessel was produced. However, the inscription "Naeja" on the buncheong bowl at the National Museum of Korea has no corresponding government office. "Naeja" is in fact a misspelling of Naeja (內資), meaning this bowl belonged to the Naejasi (內資寺, Royal Bureau of Procurement). Although "Naeja" (內子) was a misspelling of the intended Naeja (內資), it was still understood as a reference to the Naejasi since they were homophonic. Recently, buncheong ware with misspelled yet homophonous inscriptions have begun to be excavated in downtown Seoul. Examples including "Naeja" (內子) instead of Naeja (內資) and "Insu" (仁守) instead of Insu (仁壽) have been unearthed from historical sites in Seoul that functioned as consumption sites, meaning they were in fact circulated as government property despite the misspellings (whether accidental or the outcome of ignorance). Such misspelled yet homophonous inscriptions are characterized by the use of simple characters and a few sloppy strokes. Like other buncheong ware bearing the inscriptions of government office names, the bowls with the inscriptions of "Naeja" (內子) and "Insu" (仁守) were discovered at historical sites in Seoul. These misspelled homophonous inscriptions reveal that errors occurred during the process of engraving inscriptions on buncheong ware produced as a tributary payment during the early Joseon Dynasty and that buncheong ware with such errors were still distributed.

Investigation of Viscoelastic Properties of EPDM/PP Thermoplastic Vulcanizates for Reducing Innerbelt Weatherstrip Squeak Noise of Electric Vehicles (전기차 인너벨트 웨더스트립용 EPDM/PP Thermoplastic Vulcanizates 재료설계인자에 따른 점탄성과 글라스 마찰 소음 상관관계 연구)

  • Cho, Seunghyun;Yoon, Bumyong;Lee, Sanghyun;Hong, Kyoung Min;Lee, Sang Hyun;Suhr, Jonghwan
    • Composites Research
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    • v.34 no.3
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    • pp.192-198
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    • 2021
  • Due to enormous market growing of electric vehicles without combustion engine, reducing unwanted BSR (buzz, squeak, and rattle) noise is highly demanded for vehicle quality and performance. Particularly, innerbelt weatherstrips which not only block wind noise, rain, and dust from outside, but also reduce noise and vibration of door glass and vehicle are required to exhibit high damping properties for improved BSR performance of the vehicle. Thermoplastic elastomers (TPEs), which can be recycled and have lighter weight than thermoset elastomers, are receiving much attention for weatherstrip material, but TPEs exhibit low material damping and compression set causing frictional noise and vibration between the door glass and the weatherstrip. In this study, high damping EPDM (ethylene-propylene-diene monomer)/PP (polypropylene) thermoplastic vulcanizates (TPV) were investigated by varying EPDM/PP ratio and ENB (ethylidene norbornene) fraction in EPDM. Viscoelastic properties of TPV materials were characterized by assuming that the material damping is directly related to the viscoelasticity. The optimum material damping factor (tanδ peak 0.611) was achieved with low PP ratio (14 wt%) and high ENB fraction (8.9 wt%), which was increased by 140% compared to the reference (tanδ 0.254). The improved damping is believed due to high fraction of flexible EPDM chains and higher interfacial slippage area of EPDM particles generated by increasing ENB fraction in EPDM. The stick-slip test was conducted to characterize frictional noise and vibration of the TPV weatherstrip. With improved TPV material damping, the acceleration peak of frictional vibration decreased by about 57.9%. This finding can not only improve BSR performance of electric vehicles by designing material damping of weatherstrips but also contribute to various structural applications such as urban air mobility or aircrafts, which require lightweight and high damping properties.

Project of Improving Good Agriculture Practice and Income by Intergrated Agricultural Farming (미얀마 우수농산물 재배기술 전수사업)

  • Lee, Young-Cheul;Choi, Dong-Yong
    • Journal of Practical Agriculture & Fisheries Research
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    • v.16 no.1
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    • pp.193-206
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    • 2014
  • The objectives of the project are to increase farmers' income through GAP and to reduce the loss of agricultural produce, for which the Korean partner takes a role of transferring needed technologies to the project site. To accomplish the project plan, it is set to implement the project with six components: construction of buildings, installation of agricultural facilities, establishment of demonstration farms, dispatching experts, conducting training program in Korea and provision of equipments. The Project Management Committee and the Project Implementation Team are consisted of Korean experts and senior officials from Department of Agriculture, Myanmar that managed the project systematically to ensure the success of the project. The process of the project are; the ceremony of laying the foundation and commencing the construction of training center in April, 2012. The Ribbon Cutting Ceremony for the completion of GAP Training Center was successfully held under PMC (MOAI, GAPI/ARDC) arrangement in SAl, Naypyitaw on June 17, 2012. The Chairman of GAPI, Dr. Sang Mu Lee, Director General U Kyaw Win of DOA, officials and staff members from Korea and Myanmar, teachers and students from SAl attended the ceremony. The team carried out an inspection and fixing donors' plates on donated project machineries, agro-equipments, vehicles, computers and printer, furniture, tools and so forth. Demonstration farm for paddy rice, fruits and vegetables was laid out in April, 2012. Twenty nine Korean rice varieties and many Korean vegetable varieties were introduced into GAP Project farm to check the suitability of the varieties under Myanmar growing conditions. Paddy was cultivated three times in DAR and twice in SAl. In June 2012, vinyl houses were started to be constructed for raising seedlings and finished in December 2012. Fruit orchard for mango, longan and dragon fruit was established in June, 2012. Vegetables were grown until successful harvest and the harvested produce was used for panel testing and distribution in January 2013. Machineries for postharvest handling systems were imported in November 2012. Setting the washing line for vegetables were finished and the system as run for testing in June 2013. New water tanks, pine lines, pump house and electricity were set up in October 2013.

An Intelligence Support System Research on KTX Rolling Stock Failure Using Case-based Reasoning and Text Mining (사례기반추론과 텍스트마이닝 기법을 활용한 KTX 차량고장 지능형 조치지원시스템 연구)

  • Lee, Hyung Il;Kim, Jong Woo
    • Journal of Intelligence and Information Systems
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    • v.26 no.1
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    • pp.47-73
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    • 2020
  • KTX rolling stocks are a system consisting of several machines, electrical devices, and components. The maintenance of the rolling stocks requires considerable expertise and experience of maintenance workers. In the event of a rolling stock failure, the knowledge and experience of the maintainer will result in a difference in the quality of the time and work to solve the problem. So, the resulting availability of the vehicle will vary. Although problem solving is generally based on fault manuals, experienced and skilled professionals can quickly diagnose and take actions by applying personal know-how. Since this knowledge exists in a tacit form, it is difficult to pass it on completely to a successor, and there have been studies that have developed a case-based rolling stock expert system to turn it into a data-driven one. Nonetheless, research on the most commonly used KTX rolling stock on the main-line or the development of a system that extracts text meanings and searches for similar cases is still lacking. Therefore, this study proposes an intelligence supporting system that provides an action guide for emerging failures by using the know-how of these rolling stocks maintenance experts as an example of problem solving. For this purpose, the case base was constructed by collecting the rolling stocks failure data generated from 2015 to 2017, and the integrated dictionary was constructed separately through the case base to include the essential terminology and failure codes in consideration of the specialty of the railway rolling stock sector. Based on a deployed case base, a new failure was retrieved from past cases and the top three most similar failure cases were extracted to propose the actual actions of these cases as a diagnostic guide. In this study, various dimensionality reduction measures were applied to calculate similarity by taking into account the meaningful relationship of failure details in order to compensate for the limitations of the method of searching cases by keyword matching in rolling stock failure expert system studies using case-based reasoning in the precedent case-based expert system studies, and their usefulness was verified through experiments. Among the various dimensionality reduction techniques, similar cases were retrieved by applying three algorithms: Non-negative Matrix Factorization(NMF), Latent Semantic Analysis(LSA), and Doc2Vec to extract the characteristics of the failure and measure the cosine distance between the vectors. The precision, recall, and F-measure methods were used to assess the performance of the proposed actions. To compare the performance of dimensionality reduction techniques, the analysis of variance confirmed that the performance differences of the five algorithms were statistically significant, with a comparison between the algorithm that randomly extracts failure cases with identical failure codes and the algorithm that applies cosine similarity directly based on words. In addition, optimal techniques were derived for practical application by verifying differences in performance depending on the number of dimensions for dimensionality reduction. The analysis showed that the performance of the cosine similarity was higher than that of the dimension using Non-negative Matrix Factorization(NMF) and Latent Semantic Analysis(LSA) and the performance of algorithm using Doc2Vec was the highest. Furthermore, in terms of dimensionality reduction techniques, the larger the number of dimensions at the appropriate level, the better the performance was found. Through this study, we confirmed the usefulness of effective methods of extracting characteristics of data and converting unstructured data when applying case-based reasoning based on which most of the attributes are texted in the special field of KTX rolling stock. Text mining is a trend where studies are being conducted for use in many areas, but studies using such text data are still lacking in an environment where there are a number of specialized terms and limited access to data, such as the one we want to use in this study. In this regard, it is significant that the study first presented an intelligent diagnostic system that suggested action by searching for a case by applying text mining techniques to extract the characteristics of the failure to complement keyword-based case searches. It is expected that this will provide implications as basic study for developing diagnostic systems that can be used immediately on the site.

Various Life Conditions of Actors of Joseon Periods in Unofficial Historical Stories (야담 문학에 나타난 조선 배우의 삶)

  • Choi, Nakyong
    • (The) Research of the performance art and culture
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    • no.23
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    • pp.281-312
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    • 2011
  • The aim of this study is to examine various life conditions of actors of Joseon periods in unofficial historical stories. Yadam Literature(Korean unofficial historical stories) had been collected Sadaebu(the past Korean nobility and Confucian intelligentsia) among the people that stories had been handed down orally. and they had been wrote them. So Yadam Literature was heterozygous between the folk culture and the ruling class. And it was mixed and adapted legends and folktales, adding literary imagination. had a decisive role to cultivating novel that owed much to prosaic inspiration during A. D. 18~19. Besides, set a high value on excellent novel itself. Yadam Literature had a verisimilitude because it described a contemporary reality as it was founded on freely prosaic inspiration. In those days, so called Suchok and Seunggwangdae had performed Uhee(a comic theatrical performance) in Joseon periods. Suchok was the lowest class of people and Seunggwangdae was performing Buddhist monk in that time. Uhee had performed three kinds of comedies. One satirized and insinuated kings. Other satirized corrupt officials, too. Another had mimic everything. It is famous at that time as a king knew repertoire. Confucian scholars very were fond of Uhee in those ages. Because they favored a criticism of Uhee's satire. They thought that it gave people good lesson or instruction. Heri Bergson said that comic and Humor included lesson. At that time, those thought were universal in the world whether east or west. At any rate, I classify six kinds of types Uhee in Yadam Literature. First, satirizing and accusing corrupt officials. Second, an actor who use a satire in order to appeal secure a government position of his lord to a king. Third, shamans and actors who use a satire in order to appeal sufferings themselves to a king. Forth, actors and performing Buddhist monks that skillfully mimic anything. Fifth, describing actor's extremely miserable life. Sixth, wit and humor of actors. The contents of Uhee were various. Korean traditional actors adeptly dealt with aspects comic of wit, satire, humor, etc. Sometimes they used changeable transition them. By doing that, a great number of people enjoyed fully the sense of freedom. Korean traditional actors were the lowest class of people. They had lived extremely miserable life. But they had been exist as actions, interactions, and relationship in society those days. they were not only open to people, but also might foster community to peoples.

A Study on the Excavated Sab(a funeral fan) from Lime-filled Tomb and Lime-layered Tomb during the Joseon Dynasty (조선시대 회격·회곽묘 출토 삽(翣)에 대한 고찰)

  • Yi, Seung Hae;An, Bo Yeon
    • Korean Journal of Heritage: History & Science
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    • v.41 no.2
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    • pp.43-59
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    • 2008
  • Sap(?, a funeral fan) is a funeral ceremonial object used in association with a Confucian ceremonial custom, which was crafted by making a wooden frame, attaching a white cloth or a thick paper onto it, drawing pictures on it, and making a holder for a handle. According to Liji(Records of Rites), Sap was used since the Zhou Dynasty, and these Chinese Sap examples are no big different than the Korean Sap examples, which were described in Joseon Wangjo Sillok(Annals of the Joseon Dynasty), Gukjo Oryeui(the Five Rites of the State), and Sarye Pyeollam(Handbook on Four Rituals). This study explored Sap excavated in lime-filled tombs and lime-layered tombs of aristocrats dating back to Joseon, as well as their historical records to examine Sap's characteristics according to their examples, manufacturing methods, and use time. The number and designs of Sap varied according to the deceased' social status aristocrats used mainly one pair of 亞-shaped Bulsap, and a pair of Hwasap with a cloud design depicted on it. A Sap was wrapped twice with Chojuji paper or Jeojuji paper, and for the third time with Yeonchangji paper. Then, it was covered with a white ramie, a hemp, a cotton, a silk satin, etc. Bobul(an axe shape and 亞-shape design) was drawn on both sides of Sap, and a rising current of cloud was drawn at the peripheral area mainly with red or scarlet pigments. Sap, which were excavated from aristocrats'lime-filled and lime-layered tombs, are the type of Sap which were separated from its handle. These excavated Sap are those whose long handles were burnt during the death carriage procession, leaving Sap, which later were erected on both sides of the coffin. The manufacturing process of excavated relics can be inferred by examining them. The excavated relics are classified into those with three points and those with two points according to the number of point. Of the three-point type(Type I), there is the kind of relic that was woven into something like a basket by using a whole wood plate or cutting bamboo into flat shapes. The three-point Sap was concentrated comparatively in the early half of Joseon, and was manufactured with various methods compared with its rather unified overall shape. In the meantime, the two-point Sap was manufactured with a relatively formatted method; its body was manufactured in the form of a rectangle or a reverse trapezoid, and then its upper parts with two points hanging from them were connected, and the top surface was made into a curve(Type II) or a straight line(Type III) differentiating it from the three-point type. This manufacturing method, compared with that of the three-point type, is simple, but is not greatly different from the three-point type manufacturing method. In particular, the method of crafting the top surface into a straight line has been used until today. Of the examined 30 Sap examples, those whose production years were made known from the buried persons'death years inscribed on the tomb stones, were reexamined, indicating that type I was concentrated in the first half of the $16^{th}$ century. Type II spanned from the second half of the $16^{th}$ century to the second half of the $17^{th}$ century, and type III spanned from the first half of the $17^{th}$ century to the first half of the $18^{th}$ century. The shape of Sap is deemed to have changed from type I to type II and again from type II to type III In the $17^{th}$ century, which was a time of change, types II and III coexisted. Of the three types of Sap, types II and III re similar because they have two points; thus a noteworthy transit time is thought to have been the middle of the $16^{th}$ century. Type I compared with types II and III is thought to have required more efforts and skills in the production process, and as time passed, the shape and manufacturing methods of Sap are presumed to have been further simplified according to the principle of economy. The simplification of funeral ceremonies is presumed to have been furthered after Imjinwaeran(Japanese invasion of Joseon, 1592~1598), given that as shown in the Annals of King Seonjo, state funerals were suspended several times. In the case of Sap, simplification began from the second half of the $16^{th}$ century, and even in the $18^{th}$ century, rather than separately crafting Sap, Sap was directly drawn on the coffin cover and the coffin. However, in this simplification of form, regulations on the use of Sap specified in Liji were observed, and thus the ceremony was rationally simplified.

The study of growth and characterization of $AgInSe_2$ single crystal thin film by hot wall epitaxy (Hot Wall Epitaxy(HWE)에 의한 $AgInSe_2$단결정 박막 성장과 특성에 관한 연구)

  • 홍광준
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.9 no.2
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    • pp.197-206
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    • 1999
  • The stochiometric mixture of evaporating materials for the $AgInSe_2$single crystal thin films were prepared from horizontal furnace. Using extrapolation method of X-ray diffraction patterns for the $AgInSe_2$polycrystal, it was found tetragonal structure whose lattice constant $a_0$ and $C_0$ were 6.092 $\AA$ and 11.688 $\AA$, respectively. To obtain the single crystal thin films of AgInSe$_2$, the mixed crystal was deposited on thoroughly etched semi-insulator GaAs(100) substrate by HWE system. The source and substrate temperature were fixed to $610^{\circ}C$ and $450^{\circ}C$ respectively, and the thickness of the single thin films was obtained to 3.8 $\mu\textrm{m}$. The crystallization of single crystal thin films was investigated by the photoluminescence (PL) and double crystal X-ray dirrfaction (DCXD). The Hall effect was measured by the method of van der Pauw and carrier density and mobility dependence on temperature were studied. The carrier density and mobility of $AgInSe_2$single crystal thin films deduced from Hall data are $9.58{\times}10^{22} electron/m^3,\; 3.42{\times}10^{-2}m^2/V{\cdot}s$ at 293 K, respectively. From the photocurrent spectrum by illumination of perpendicular light on the c-axis of the $AgInSe_2$single crystal thin film, the spin orbit coupling $\Delta$So and the crystal field splitting $\Delta$Cr were obtained to 0.29 eV and 0.12 eV at 20 K respectively. From PL peaks measured at 20 K, 881.1 nm (1.4071 eV) and 882.4 nm (1.4051 eV) mean $E_x^U$ the upper polariton and $E_x^L$ the lower polariton of the free exciton $(E_x)$, also 884.1 nm (1.402 eV) express $I_2 peak of donor-bound exciton emission and 885.9 nm (1.3995 Ev) emerges $I_1$ peak of acceptor-bound exciton emission. In addition, the peak observed at 887.5 nm (1.3970 eV) was analyzed to be PL peak due to DAP.

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