• 한국대기환경학회지
• /
• 제20권6호
• /
• pp.749-758
• /
• 2004

Nitrous oxide ($N_2$O) has been known as an important trace gas due to the greenhouse gas and the major source of stratospheric oxide of nitrogen (NO). Soil is the major source of $N_2$O in nature. The physicochemical characteristics of soils affect the emission of $N_2$O from soil. These physicochemical parameters are soil moisture, soil temperature, and soil N content. Since these parameters are correlated to the flux of $N_2$O from soil individually and compositely, there still remain many unknowns in the mechanism to produce $N_2$O in soil and the roles of such physicochemical parameters which affect the soil $N_2$O emission. Soil $N_2$O fluxes were measured at different levels in water filled pore space (WFPS), soil temperature and soil N contents from the same amounts of soils which were sampled from agriculturally managed upland field in a depth of ～30 cm at Kunsan. The soil $N_2$O flux measurements were conducted in a laboratory with a closed flux chamber system. The optimum soil moisture and soil temperature were observed at 60% of WFPS and ～13$^{\circ}C$. The soil $N_2$O flux increased as soil N contents increases during the whole experimental hours (up to 48 hours). However, average $N_2$O flux decreased after ～30 hours when organic carbon was mixed with nitrogen in the sample soils. It is suggested that organic carbon could be important for the emission of $N_2$O, and that the ratio of N to C needs to be identified in the process of $N_2$O soil emission.

• 식물분류학회지
• /
• 제39권4호
• /
• pp.247-253
• /
• 2009

한국산 쑥속 20분류군의 분류를 위하여 체세포 염색체수를 조사하였다. 본 연구에서 취급된 분류군들의 체세포 염색체수는 2n = 16, 18, 34, 36, 50, 52, 54로서 기본 염색체수는 x=8, 9, 10, 13, 17이었으며, 실제비쑥(A. japonica var. angustissima 2n = 36)의 체세포염색체수는 본 연구에서 처음으로 밝혀졌다. 사철쑥 (A. capillaris 2n = 18), 섬쑥(A. japonica var. hallaisanensis 2n = 36), 갯제비쑥(A. japonica subsp. littoricola 2n = 36), 개똥쑥(A. annua 2n = 18), 개사철쑥(A. carvifolia 2n = 18), 큰비쑥(A. fukudo 2n = 16), 맑은대쑥(A. keiskeana 2n = 18), 넓은잎외잎쑥(A. stolonifera 2n = 36), 그늘쑥(A. sylvatica 2n = 16), 물쑥(A. selengensis 2n = 36), 산쑥 (A. montana 2n = 52), 뺑쑥(A. lancea 2n = 16), 산흰쑥(A. sieversiana 2n = 18) 등의 13분류군의 염색체수는 기존 보고와 일치하였으며, 기존 보고와 다르게 파악된 종류는 제비쑥(A. japonica var. japonica 2n = 18, 36 vs 2n = 36), 더위지기(A. sacrorum 2n = 18, 54 vs 2n = 54), 덤불쑥(A. rubripes 2n = 16, 34 vs 2n = 16), 쑥(A. indica 2n = 34, 36 vs 2n = 34), 참쑥(A. codonocephala 2n = 18, 50, 54 vs 2n = 50), 황해쑥(A. argyi 2n = 34, 36, 50 vs 2n = 34)의 6분류군이었다. 한국산 쑥속의 체세포 염색체수는 제비쑥, 더위지기, 참쑥, 황해쑥, 산쑥, 그늘쑥의 분류에 매우 유용한 형질이었다.

• 한국표면공학회:학술대회논문집
• /
• 한국표면공학회 2014년도 추계학술대회 논문집
• /
• pp.304-304
• /
• 2014

Quaternary Ti-Al-Si-N films were deposited on WC-Co substrates by a hybrid deposition system of arc ion plating (AIP) method for Ti-Al source and DC magnetron sputtering technique for Si incorporation. The synthesized Ti-Al-Si-N films were revealed to be composites of solid-solution (Ti,Al)N crystallites and amorphous $Si_3N_4$ by instrumental analyses. The Si addition in Ti-Al-N films affected the refinement and uniform distribution of crystallites by percolation phenomenon of amorphous silicon nitride, similarly to Si effect in TiN film. As the Si content increased up to about 9 at.%, the hardness of Ti-Al-N film steeply increased from 30 GPa to about 50 GPa. The highest microhardness value (~50 GPa) was obtained from the Ti-Al-Si-N film having the Si content of 9 at.%, the microstructure of which was characterized by a nanocomposite of $nc-(Ti,Al)N/a-Si_3N_4$.

• 한국표면공학회지
• /
• 제39권3호
• /
• pp.110-114
• /
• 2006

In this work, comparative studies on microstructure and mechanical properties between $Mo_2N$ and Mo-Si-N coatings were conducted. Ternary Mo-Si-N coatings were deposited on AISI D2 steel substrates by a hybrid method, where AIP technique was combined with a magnetron sputtering technique. Instrumental analyses of XRD, HRTEM, and XPS revealed that the Mo-Si-N coatings must be a composite consisting of fine $Mo_2N$ crystallites and amorphous $Si_3N_4$. The hardness value of Mo-Si-N coatings significantly increased from 22 GPa of $Mo_2N$ coatings to about 37 GPa with Si content of 10 at.% due to the refinement of $Mo_2N$ crystallites and the composite microstructure characteristics. The average friction coefficient of the Mo-Si-N coatings gradually decreased from 0.65 to 0.4 with increasing Si content up to 15 at.%. The effects of Si content on microstructure and mechanical properties of Mo-N coatings were systematically investigated.

• BMB Reports
• /
• 제47권5호
• /
• pp.256-261
• /
• 2014

To investigate the function of N-glycosylation of Cel5A (endoglucanase II) from Hypocrea jecorina, two N-glycosylation site deletion Cel5A mutants (rN124D and rN124H) were expressed in Saccharomyces cerevisiae. The weights of these recombinant mutants were 54 kDa, which were lower than that of rCel5A. This result was expected to be attributed to deglycosylation. The enzyme activity of rN124H was greatly reduced to 60.6% compared with rCel5A, whereas rN124D showed slightly lower activity (10%) than that of rCel5A. rN124D and rN124H showed different thermal stabilities compared with the glycosylated rCel5A, especially at lower pH value. Thermal stabilities were reduced and improved for rN124D and rN124H, respectively. Circular dichroism spectroscopy showed that the modification of secondary structure by mutation may be the reason for the change in enzymatic activity and thermal stability.

• Journal of Ceramic Processing Research
• /
• 제19권5호
• /
• pp.439-443
• /
• 2018

The outstanding characteristics of high quality GaN single crystal substrates make it possible to apply the manufacture of high brightness light emitting diodes and power devices. However, it is very difficult to obtain high quality GaN substrate because the process conditions are hard to control. In order to effectively control the formation of GaN polycrystals during the bulk GaN single crystal growth by the HVPE (hydride vapor phase epitaxy) method, a quartz ring was introduced in the edge of substrate. A variety of evaluating method such as high resolution X-ray diffraction, Raman spectroscopy and photoluminescence was used in order to measure the effectiveness of the quartz ring. A secondary ion mass spectroscopy was also used for evaluating the variations of impurity concentration in the resulting GaN single crystal. Through the detailed investigations, we could confirm that the introduction of a quartz ring during the GaN single crystal growth process using HVPE is a very effective strategy to obtain a high quality GaN single crystal.

• 정보처리학회논문지A
• /
• 제11A권3호
• /
• pp.173-180
• /
• 2004

계층적 자료구조인 사진트리는 영상을 표현하는데 매우 중요한 자료구조이다. 사진트리를 메모리에 저장하는 방법 중 선형 사진트리 표현방법은 다른 표현 방법과 비교할 때 저장 공간을 매우 효율적으로 절약할 수 있는 이점이 있기 때문에 사진트리와 관련된 연산의 수행을 위해 선형 사진트리를 사용하는 효율적인 알고리즘 개발에 많은 연구가 진행되어 왔다. 영역 확장은 영상을 주어진 거리만큼 확장시키는 연산이고, 스케일링은 영상을 주어진 크기만큼 증폭시키는 연산으로 영상의 기하학적 연산에 속한다. 본 논문에서는 RMESH(Reconfigulrable MESH) 구조에서 3-차원 n${\times}$n${\times}$n 프로세서를 사용하여 선형 사진트리로 표면된 영상의 영역 확장과 스케일링을 수행하는 효율적인 알고리즘을 제안한다. 이 알고리즘은 n${\times}$n${\times}$n RMESH의 계층구조에서 선형 사진트리의 위치코드들을 효율적으로 전송할 수 있는 기본적인 연산들을 이용함으로써 상수 시간의 시간복잡도를 갖는다.

• 대한물리의학회지
• /
• 제16권3호
• /
• pp.65-80
• /
• 2021

PURPOSE: This study was conducted as a literature review to analyze the research trends related to the International Classification of Functioning, Disability and Health (ICF) in Korea from 2015 to 2020. METHODS: Precedent studies were searched with the search term "ICF" or "international classification of functioning, disability and health" from the databases of RISS, KISS, DBpia, and Pubmed. The inclusion criteria are that the studies have been carried out in Korea from 2015 to 2020 using ICF by researchers consisting of one or more Koreans and have been peer-reviewed. RESULTS: Of the total 269 studies, 107 that met the inclusion criteria were analyzed. It was found that these studies were published at a similar frequency each year. The most common area of expertise was identified as the clinical area (n = 67), followed by special education (n = 21) and social welfare (n = 13). The study subject groups were mostly patients (n = 39), disabled people (n = 25), and related experts (n = 13). The most common research topic was functioning evaluation (n = 49) and followed by a literature review (n = 29), and the most frequently used components in all the areas of expertise were activity and participation (n = 98), body function and structure (n = 73), and environmental factors (n = 61). CONCLUSION: For the past six years, domestic ICF-related research has been conducted in a wider range of expertise areas on more subdivised subject groups. Continuous research, development of standardized curricula and contents, and development of coding tools are considered to be important in vitalizing the use of the ICF.

• 대한수학회지
• /
• 제57권4호
• /
• pp.1005-1018
• /
• 2020

A characterization of the C-projective vector fields on a Randers space is presented in terms of 𝚵-curvature. It is proved that the 𝚵-curvature is invariant for C-projective vector fields. The dimension of the algebra of the C-projective vector fields on an n-dimensional Randers space is at most n(n + 2). The generalized Funk metrics on the n-dimensional Euclidean unit ball 𝔹ⁿ(1) are shown to be explicit examples of the Randers metrics with a C-projective algebra of maximum dimension n(n+2). Then, it is also proved that an n-dimensional Randers space has a C-projective algebra of maximum dimension n(n + 2) if and only if it is locally Minkowskian or (up to re-scaling) locally isometric to the generalized Funk metric. A new projective invariant is also introduced.

• 한국표면공학회지
• /
• 제35권4호
• /
• pp.211-217
• /
• 2002

Ti-Si-N films were deposited onto WC-Co substrate by a RF-PECVD technique. The deposition behaviors of Ti-Si-N films were investigated by varying the deposition temperature, RF power, and reaction gas ratio (Mx). Ti-Si-N films deposited at 500, 180W, and Mx 60% had a maximum hardness value of 38GPa. The microstructure of films with a maximum hardness was revealed to be a nanocomposite of TiN crystallites penetrated by amorphous silicon nitride phase by HRTEM analyses. The microstructure of maximum hardness with Si content (10 at.%) was revealed to be a nanocomposite of TiN crystallites penetrated by amorphous silicon nitride phase, but to have partly aligned structure of TiN and some inhomogeniety in distribution. and At above 10 at.% Si content, TiN crystallite became finer and more isotropic also thickness of amorphous silicon nitride phase increased at microstructure.