Electronic transport and carrier concentration in conductive ZnO:Ga thin films

Nahm, C.,Shin, S.,Lee, W.,Kim, J.I.,Jung, D.R.,Kim, J.,Nam, S.,Byun, S.,Park, B. Elsevier 2013 Current Applied Physics Vol.13 No.2

Transparent and conductive Ga-doped ZnO (ZnO:Ga) films were post-annealed after sputter deposition, and their structural and electrical properties were investigated. Post-annealing led to an improvement of crystallinity along the [001] direction, but did not change lateral grain size. Therefore, carrier concentration and electron mobility of films were analyzed as a function of crystallinity. The electrical parameters were obtained with both optical reflectance based on the Drude free-electron model and the Hall method, and similar tendencies were observed within the two methods. Even though the lowest resistivity was demonstrated by the film annealed at 550 <SUP>o</SUP>C, the optimum values for carrier concentration and mobility were observed in films with different post-annealing temperatures.

Topographical evolution and ¹⁴C age dating of the construction of the Eurimji reservoir (Jecheon, Korea)

Nahm, W.H.,Kim, J.K.,Kim, J.Y.,Lim, J.,Kim, J.C.,Yu, K.M. Academic Press 2012 Journal of archaeological science Vol.39 No.12

The Eurimji site in Jecheon City, Chungcheong Province holds major importance for Korean cultural heritage because it is assumed to be the oldest man-made reservoir for rice field irrigation in Korea. A multiproxy study provides the first scientific dating of the levee construction. The authors retrieved two sediment cores from the levee (core ER-1, 18.00 m long) and the reservoir bottom (core ER-3-1, 6.98 m long). Several plant fragment layers were observed between layers of dark gray clay-silt sediment in unit 2 of both cores. The spacing and thickness of these plant layers was relatively uniform (from 50 to 90 cm, and 5 to 6 cm, respectively). These features are interpreted to represent part of a man-made sedimentary sequence created using the consolidation-settlement drain method (tamped-earth or rammed-earth method) commonly used for dam or fortress construction in ancient times, as the features are not characteristic of natural river sedimentary processes. In this alternating sequence, bulk carbon from the sediment yielded AMS <SUP>14</SUP>C dates of 2000-1400 <SUP>14</SUP>C yr BP, and the plant materials yielded dates of 1300-1200 <SUP>14</SUP>C yr BP. If workers at that time used two different materials such as available plant materials and clays for levee construction, the plant material is preferred for <SUP>14</SUP>C age dating. This is because the origin of the carbon in the sediments is ambiguous, but the source of the plant materials has been confidently determined to be equivalent to the time of the levee construction. Therefore, the levee was constructed between 1200 and 1100 <SUP>14</SUP>C yr BP (AD 800-900), which is later than previously thought (i.e., AD 300 or AD 550). The results of our study also indicate that wetlands existed in the area before the construction of the Eurimji levee.

The Word Stress Rules in Korean

Nahm, Yong-Woo The Korean Society Of Phonetic Sciences And Speech 1987 말소리 Vol.11 No.-

Radioimmuno assay of Carcinoembrionic Antigen

Nahm, Sook Hyun 고려대학교 의과대학 1978 고려대학교 의과대학 잡지 Vol.15 No.2

Catalytic Effect of Metal Elements on the Growth of GaN and Mg-doped GaN Micro-Crystals

Nahm, Kee Suk,Kim, Tae Yun,Lee, Sang Hyun 한국화학공학회 2003 Korean Journal of Chemical Engineering Vol.20 No.4

Catalytic effect of metal elements was observed in the growth of GaN and Mg-doped GaN micro-crystals. High quality GaN micro-crystals were synthesized by direct reaction of gallium and ammonia using a Ni-mesh catalyst. Mg-doped GaN micro-crystals were also grown by the same reaction scheme in the presence of MgCl₂. The growth rate of GaN micro-crystals markedly increased in the presence of the catalyst. The average grain size of GaN microcrystals synthesized in the presence of Ni and Mg metals was larger than that in the absence of the metals. The characterization of the catalytically grown GaN micro-crystals using transmission electron microscopy and X-ray and/or electron diffraction pattern showed the growth of dislocation free hexagonal GaN micro-crystals. Photoluminescence (PL) and Catholuminescence (CL) measurements also showed the growth of good quality n- and p-type GaN microcrystals using Ni catalyst

Vegetational and Sedimentary Responses to the Middle Holocene Climate Deterioration of the Yeongsan Estuary, Southwestern Korea

Nahm Wook-Hyun,Bong Pil-Yoon,Yang Dong-Yoon,Kim Ju-Yong,Yu Kang-Min 한국고생물학회 2006 정기총회 및 학술발표회 Vol.2006 No.-

A Study on the Reducing Pollutants in Non-Ruminant Manure by Increasing Feed Utilization

Nahm, K.H. The Korean Society of Poultry Science 2001 韓國家禽學會誌 Vol.28 No.3

가축사육이 집단화되면서 가축배설물의 축적은 집중화 현상을 초래하게 되었고 또 계속적인 분뇨 분비물의 유출은 환경공해의 요인이 되고 있으며 이는 공공의 걱정거리로 대두되고 있다. 가축분뇨 중에서 질소와 인이 환경공해요인이 되는 가장 중요한 영양소이지만 가축이나 축산시설물에서 발생되는 냄새 역시 공해의 요인이 되고 있다. 급여되는 사료의 영양소효율을 높이는 길이 환경공해를 감소시키는 방법이다. 가장 많은 실험은 닭과 돼지를 대상으로 하여 이루어졌다. 사료첨가제의 이용, 사양방법의 수정 등으로 사료중의 영양소 이용성을 높임으로서 질소와 인의 배출감소는 물론 냄새와 분의 건물함량을 줄일 수 있었다. 1) 합성아미노산 제제를 사료 중에 첨가하고 단백질 수준을 감소시켰을 때 육계의 경우 10∼27%의 질소배출을 기대할 수 있었으며 산란계의 경우 18∼35%, 돼지의 경우 62%, 돼지에서 생성되는 냄새를 9∼43%까지 감소시키는 효과를 기대 할 수 있었다. 2) 사료 중에 효소제를 첨가하였을 때 육계 분의 건물함량을 12∼15% 감소시킬 수 있었다. 3) phytase를 첨가할 경우 분으로 배설되는 인의 함량은 양계의 경우 25∼35%,돼지의 경우 9∼43%까지 감소가 가능했다. 4) 성장촉진제를 이용할 경우 돼지에서 질소의 배설 양을 5∼30% 감소시킬 수 있었으며 냄새는 53∼55%까지 감소가 가능했다. 5) 사료배합을 요구량에 가깝게 하여 급여하였을 때 양계나 양돈의 경우 질소와 인은 각각 10∼15% 감소를 기대 할 수 있었으며 돼지의 냄새는 28∼79%까지 감소가 가능했다. 6) 기별 사양을 철저히 실시함으로서 양계와 양돈의 경우 질소는 10∼33%, 인산은 10∼13%, 그리고 성장 비육돈의 경우 49∼79% 감소를 기대 할 수 있다. 7) 닭이나 돼지의 사료를 배합시 소화율이 높은 곡류를 이용하면 질소와 인의 배설을 5% 감소시킬 수 있다. Localization of livestock facilities leads to concentration of livestock wastes and subsequent leakage of pollutants into the environment, resulting in public concern about their effects. Nitrogen (N) and phosphorus (P) are the most harmful components of animal manure, but odor from the manure itself and the livestock facilities is also a problem. Improving the nutrient efficiency of the livestock helps to decrease excretion of these environmental contaminants. Pigs and chickens are the main experimental models used in studies to improve nutrient efficiency. Addition of feed supplements and modifying feeding systems to improve nutrient efficiency can result in significant decrease in the N, P, odor and dry matter (DM) weight of manure. Examples of these methods include the following. 1) Addition of synthetic amino acids and reducing protein contents resulted N reductions of 10∼27% in broilers, 18∼35% in chicks and layers, 19∼62% in pigs, and a 9∼43% reduction in odor in pigs. 2) Enzyme supplementation resulted in a 12∼15% reduction in DM weight in broiler manure. 3) Phvtase supplementation resulted in P reductions of 25∼35% in chickens and 20∼60% in pigs. 4) Use of growth promoting substances resulted in a 5∼30% reduction in N and a 53∼56% reduction in odor of pigs. 5) Formulating diets closer to requirements (diet modification) reduced N and P by 10∼15% each in chickens and pigs, and odor by 28∼ 79% in pigs. 6) Phase feeding reduced N and P excretion by chicken and pigs from 10∼33% and 10∼13% each, as well as odor in growing and finishing pigs by 49∼79%. 7) Use of highly digestible raw materials in feed reduced N and P excretion by 5% in chickens and pigs.

Causes of Nitrogen Loss during Animal Manure Analysis

Nahm, K.H. The Korean Society of Poultry Science 2001 韓國家禽學會誌 Vol.28 No.3

Since nitrogen(N) is a volatile compound affected by many environmental factors, determining the N content of manure tends to be difficult. Upon arrival in the laboratory, the manure should be moist and refrigerated. Manure samples will have variable N contents due to drying temperature, and the presence of soil in the sample will affect N content. Acidification of the sample prevents ammonia volatilization and should be done before drying. It is recommended that manure samples be pretreated with a strong oxidizing agent, KMnO$_4$, followed by digestion under reduced conditions (reduced Fe-$H_{2}$ $SO_{4}$ ), which achieves a complete recovery of both $NO_{3}$ -N and $NO_{2}$ -N without a low recovery of $NH_{4}$ -N, resulting in a more accurate determination of N content. Accuracy of results for N content determined by recently developed rapid analysis techniques in the field should be tested by comparison with results obtained at laboratories using approved standard methods. Most commonly, the Kjeldahl system is used to determine manure N content. More research is needed on the effects of species, breed, age and individuals on the nutrient contents of manure. The procedures for manure sampling on the farm, shipping and handling of the sample until it reaches the laboratory, and the methods of sampling of the manure at the laboratory must be studied. Development of animal agricultural laboratories where feed, manure, soil, and water are all analyzed by appropriate specialists is needed. 질소(N)는 그 자체가 환경적인 요인에 따라 영향을 받는 휘발성 물질이어서 가축의 분뇨(분에는 반드시 뇨가 묻어 있기 때문에 다음부터는 분이라는 말로 대치한다)중에 함유되어 있는 N의 함량을 정량하기란 무척 어렵다. 우선 가축의 분이 실험실에 도착하면 수분이 있는 상태에서 냉장고에 보관되어야 한다. 분중에 함유되어 있는 N는 건조 온도에 따라 함량에 변화를 일으키며 또 시료에 흙이 묻어 있는가에 따라서도 N의 함량 정량에 영향을 받는다. 시료를 산성화하면 암모니아의 휘발이 방해된다. 따라서 시료를 산성화시킬 때는 건조전에 이루어져야 한다. 분 분석을 위한 이상적인 분 전처리는 강산화제 ($KMnO_{4}$ )로 우선 처리 한 후 다시 환원제 (Fe- $H_{2}$ $SO_{4}$)를 처리한 상태에서 시료를 소화시키면 가장 정량하기 어려운 $NH_{4}$ -N도 같이 정량이 가능하며 질소의 전체정량이 정확히 이루어질 수 있다. 질소정량의 정확성이 야외에서 이루어질 수 있도록 최근 여러 가지의 약식분석방법이 개발되고 있지만 그 결과는 반드시 공인된 분석방법에 의하여 실험실에서 분석된 결과치와 비교되어야 한다. 실험실에서 일반적으로 질소 정량에 많이 이용되고 있는 방법은 켈달 분석방법이다. 앞으로 가축의 종류나 품종, 나이 또는 개체간에 대한 분의 영양소 함량에 관한 연구가 많이 이루어져야 한다. 또 분에 대한 농장에서의 시료 채취과정, 운반, 및 실험실에 도착한 후 처리 과정 그 다음 실험실에서 분석을 위한 시료채취과정 등에 대한 연구도 이루어져야 한다. 사료, 분뇨, 토양, 그리고 물을 함께 분석하는 동물농업의 발전을 필요하며 적당한 전문가의 이용이 필요하다.

Pope's View of Homer : a Critique

Nahm, Joung Sook 한국영어영문학회 1981 영어 영문학 Vol.27 No.2

Gene Profiling of Bone around Orthodontic Mini-Implants by RNA-Sequencing Analysis

Nahm, Kyung-Yen,Heo, Jung Sun,Lee, Jae-Hyung,Lee, Dong-Yeol,Chung, Kyu-Rhim,Ahn, Hyo-Won,Kim, Seong-Hun Hindawi Publishing Corporation 2015 BioMed research international Vol.2015 No.-

<P>This study aimed to evaluate the genes that were expressed in the healing bones around SLA-treated titanium orthodontic mini-implants in a beagle at early (1-week) and late (4-week) stages with RNA-sequencing (RNA-Seq). Samples from sites of surgical defects were used as controls. Total RNA was extracted from the tissue around the implants, and an RNA-Seq analysis was performed with Illumina TruSeq. In the 1-week group, genes in the gene ontology (GO) categories of cell growth and the extracellular matrix (ECM) were upregulated, while genes in the categories of the oxidation-reduction process, intermediate filaments, and structural molecule activity were downregulated. In the 4-week group, the genes upregulated included ECM binding, stem cell fate specification, and intramembranous ossification, while genes in the oxidation-reduction process category were downregulated. GO analysis revealed an upregulation of genes that were related to significant mechanisms, including those with roles in cell proliferation, the ECM, growth factors, and osteogenic-related pathways, which are associated with bone formation. From these results, implant-induced bone formation progressed considerably during the times examined in this study. The upregulation or downregulation of selected genes was confirmed with real-time reverse transcription polymerase chain reaction. The RNA-Seq strategy was useful for defining the biological responses to orthodontic mini-implants and identifying the specific genetic networks for targeted evaluations of successful peri-implant bone remodeling.</P>