Valuation of ecosystem services in the organic carbon of the Pinus densiflora forest at Mt. Namsan, Seoul Metropolitan City

Lee, Eung-Pill,Lee, Soo-In,Jeong, Heon-Mo,Han, Young-Sub,Lee, Seung-Yeon,Park, Jae-Hoon,Jang, Rae-Ha,Hong, Youg-Sik,Jung, Young-Ho,Kim, Eui-Joo,Lee, Sang-Hun,You, Young-Han The Ecological Society of Korea 2019 Journal of Ecology and Environment Vol.43 No.4

Background: Standing biomass, litter production, rate of litter decomposition, amount of litter on forest floor, and amount of soil organic carbon distribution were investigated from March 2016 to November 2018 in order to evaluate the ecosystem value through organic carbon distribution in the Pinus densiflora forest at Namsan, Seoul Metropolitan City. Results: The amount of organic carbon in the Pinus densiflora forest was 261.09 ton C ha^-1 during the research period, and fixed organic carbon in plant through net photosynthesis was 3.2 ton C ha^-1 year^-1. The organic carbon in plant was 62.77 ton C ha^-1 (24.04%), in litter on the forest floor was 3.65 ton C ha^-1 (1.40%), and in soil was 194.67 ton C ha^-1 (74.56%). The value of plant, litter on forest floor, and soil organic carbon distribution were each 6,277,000 won ha^-1, 365, 000 won ha^-1, and 19,467,000 won ha^-1. The value per ton of fixed organic carbon in plant through net photosynthesis was 320,000 won ha^-1 year^-1 and the value of ecosystem services stored in carbon in the Namsan forest ecosystem was about 26.1 million won ha^-1 for 3 years. Conclusions: The results of this study suggest that the pine forests of Namsan rapidly decompose leaves due to the high atmospheric temperature and accumulate a large amount of organic carbon in the soil to provide climate control regulatory service function.

Resistive switching characteristic of Ce0.9Y0.1O2/ TiO2 bi‑layer structure by photochemical metal‑organic deposition

Sung‑Eun Kim,Jin-Gyu Lee,In-Young Choi,Ha-Eun Kim,Hong-Sub Lee 한국세라믹학회 2020 한국세라믹학회지 Vol.57 No.1

Sneak current is one of the main bottlenecks for dense crossbar array resistive random access memory. This study reports highly non-linear resistive switching characteristic from Ce0.9Y0.1O2/ TiO2 bi-layer (1S/1R device) structure, fabricated by photochemical metal-organic deposition, as a solution for sneak current issue. Ce0.9Y0.1O2 material, possessing oxygen vacancies, was used as a potential barrier as well as oxygen reservoir which rectified the current of low resistance state without an electrical breakdown in 1S/1R device. TiO2 was adopted for resistive switching property, and TiO2 layer having mixed phase (anatase and brookite) showed typical diode switching behavior. The photochemical reaction of photochemical metal-organic deposition process and phase formation were monitored and established using by Fourier-transform infrared spectroscopy and X-ray diffraction, respectively. The 1S/1R device showed highly non-linear resistive switching characteristic, large on/ off ratio of above three orders of magnitude with low operating current.

The HBV DNA Amounts in Serum Have No relationship with ALT level and Hetergeneous Population Coexits in Chronic Hepatitis B Virus Infection

Chun, Yoon-Keun,Ha, Joo-hun,Hong-Jung-Woo,Oh, Soo-Myung,Kim, Sung-Soo 경희대학교 동서의학연구소 1999 INTERNATIONAL SYMPOSIUM ON EAST-WEST MEDICINE Vol.1999 No.1

Yoon-Keun Chun¹,Joohun Ha□Hong-Jung Woo□, Soo Myung Oh□,Sung Soo Kim□ ¹Department of Molecular Biology, College of Medicine,²Department of Surgery, college of Medicine,³Department of Internal Medicine, College of Oriental Medicine,and ⁴East-Weat Medical Reserch Institute,Kyung Hee University, Seoul, Korea. The HBV DNA Amounts in Serum Have No relationship with ALT level and Hetergeneous Population Coexits in Chronic Hepatitis B Virus Infection. Proceedings of International Symposium on East-West Medicine, Seoul. 212-230, 1999. -Hepatitis B is caused by hepadnavirus. Hepatitis B virus replicates through 3.5kb pregenomic RNA intermediate which is regulated by core promoter. Pathogenesis of hepatitis B virus has been bilieved the result of host immune response. But recently many studies have reported that high level of viral replication caused by mutation in core promoter might result in severs hepatitis. But these studies were performed in vitro, not in vivo. So there is yet debate about which factor, viral of host factor, is more important in pathogenesis of hepatitis B virus. So we measured real viral replication level in 204 chronic hepatitis B patients by quantifying HBV DNA from sera by our novel PCR-based more sensitive method, and compared these results with ALT level measured from same sera, which indicates liver cell damage. Surprisingly there are no significant correlation between HBV DNA quantity and ALT level. Then we cloned core promoter region. In SSCP, we found that many viral mutants coexist in one patient. Base on SSCP result, we chose main viral core promoter type in each patients, which is thought to determine overall viral replication level in this patient. Main type of core promoter region of each 41 patients were directly sequenced. And with these we measured promoter activity by luciferase assay system and compared promoter activity with on another. We found tha there were some differences in promoter activity according to core promoter sequences. And we constructed replication-competent viral constructs with core promoter from 41 patients and Transfected these into HepG2 cell and measured HBV DNA by southern blot. There were also differences in HBV DNA quantity according to core promoter sequences. On these all results we investigated correlation between the effect of HBV core promoter on viral replication in vitro and HBN DNA quantity, ALT level from sera of each patients. We found there is no significant correlation among them. As a result, we concluded that in determining severity chronic hepatitis B patients, host factors of each patient is more important rather than replicative activity of virus itself.

이동 환경에서 멀티캐스트 적용 방안

홍형섭(Hyung-Seop Hong),하정락(Jeoung-Lak Ha),현은희(Eun-Hee Hyun),김상하(Sang-Ha Kim) 한국정보과학회 2001 한국정보과학회 학술발표논문집 Vol.28 No.2Ⅲ

Mobile IP(MIP)[1] Working Group에서 제안하고 있는 멀티캐스트 적용 방안에는 크게 HA기반 라우팅과 FA기반 라우팅으로 구분된다. HA기반 라우팅 방법은 멀티캐스트 패킷을 HA에서 터널링하는 방법을 사용하므로 경로의 최적화가 이루어지지 않게 되며 터널 집중화 현상이 발생하게 된다. FA기반 라우팅 방법은 이동 호스트의 핸드오프가 일어날 때마다 멀티캐스트 트리의 재구성이 필요하므로 많은 오버헤드가 발생하지만 경로 최적화는 얻을 수 있다. 본 논문은 HA기반 라우팅과 FA기반 라우팅 방안을 절충한 새로운 멀티캐스트 제공 방안을 제안한다. MH의 이동이 빈번한 마이크로 레벨에서는 HA기반 라우팅을 이용하고, MH의 이동 거리가 큰 매크로 레벨에서는 경로 최적화를 위하여 새로운 멀티캐스트 트리를 재구성함으로써 보다 효율적 멀티캐스트 서비스가 가능한 메커니즘의 프로토타입을 제안한다.

분포형 토양침식지도를 이용한 한강상류지역 토양유실 위험성 평가

박찬원(Chan-Won Park),손연규(Yeon-Kyu Sonn),장용선(Yong-Seon Zhang),홍석영(S. Young Hong),현병근(Byung-Keun Hyun),송관철(Kwan-Cheol Song),하상건(Sang-Keun Ha),문용희(Young-Hee Moon) 한국토양비료학회 2010 한국토양비료학회지 Vol.43 No.6

본 연구에서는 1:25,000 정밀토양도 등 가용한 공간자료를 이용하여 작성된 토양유실도를 이용하여 한강 상류지역 10개 중권역 108 소유역에 대하여 토양유실량 평가하고 토지이용별 토양유실 위험지역을 분석하였다. 대상유역 총 토양유실량은 895만 Mg yr<SUP>-1</SUP>으로 예측되었으며, 면적당 평균 토양유실량은 6.1 Mg ha<SUP>-1</SUP>yr<SUP>-1</SUP>이었다. 중소유역 단위로 살펴보면 남한강지역이 북한강지역의 유실량 뿐만 아니라 면적당 유실량이 더 많았다. 이는 북한강 권역의 경우 화강암 및 화강편마암이 주요 모재인 반면에 남한강 권역의 경우 토양모재가 퇴적암지대를 많이 포함있어 토양침식성 인자 (K factor)와 경사 인자 (LS factor)가 상대적으로 높고, 남한강 지역의 경우 농경지 토양이 상대적으로 많이 분포하고 있기 때문으로 판단된다. 대상유역의 토지이용별 연평균 토양유실량을 분석한 결과 산림/초지 > 밭 >> 도심/대지 >> 논 > 과수의 순로 분석 대상유역 중 10.7%를 차지하고 있는 농경지에서 유실되는 토양의 추정량은 41.3%이였으며, 이중 6.2%면적을 차지하는 밭이 40.6%으로 44.2%의 산림/초지와 비슷한 수준이었다. 한강상류지역 토양유실 위험성 평가시 분포형 토양침식지도와 항공사진을 비교한 결과 토양유실에 대한 공간인 정보를 확실하게 보여주고 있으며, 토양침식위험성은 남한강권역의 남한강 상류 (1001), 평창강 (1002), 충주댐 (1003) 권역에서 각각 토양침식위험성이 “보통”이상으로 높은 지역이 각각 8.7%, 7.9%, 7.8%로 평균인 5.9%보다 높았으며, 이에 대한 보전방안이 강구될 필요가 있고 판단된다. This study was conducted to evaluate soil erosion risk with a standard unit watershed in the upper Han river basin using the spatial soil erosion map according to the change of landuse. The study area is 14,577 ㎢, which consists of 10 subbasins, 107 standard unit watersheds. Total annual soil loss and soil loss per area estimated were 895 × 10<SUP>4</SUP> Mg yr<SUP>-1</SUP> and 6.1 Mg ha<SUP>-1</SUP> yr<SUP>-1</SUP>, respectively. A result of analysis with a subbasin as a unit showed that annual soil losses and soil loss per area in Namhan river basins was more than in Bukhan river ones. Predicted annual soil loss according to the landuse ranked as Forest & Grassland > Upland >> Urban & Fallow area > Paddy field > Orchard. Upland area covered 6.2% of the study area, but the contribution of total annul soil loss was 40.6% and that of Forest & Grassland was 44.2%. As a evaluation of soil erosion risk using the spatial soil erosion map, we could precisely conformed the potential hazardous region of soil erosion in each unit watersheds. The ratio of regions, graded as higher “Moderate” for annual soil loss, were respectively 8.7%, 7.9% and 7.8% in 1001, 1002 and 1003 subbasins in Namhan river basin. Most landuse of these area was upland, and these area is necessary to establish soil conservation practices to reduce soil erosion based on the field observation.

PO35 : Effect of Mesoporous Solid Catalysts on Biodiesel Production from Waste Cooking Oil by Supercritical Methanol Process

( Sung Ha Hong ),( Tae Ha Kim ),( Md Sufi Ullah Siddik Bhuyan ),( Kwan Ju Lee ),( Myung Chul Shin ),( Young Hwan Chu ),( Yong Chan Seo ) 한국폐기물자원순환학회(구 한국폐기물학회) 2013 한국폐기물자원순환학회 심포지움 Vol.2013 No.4

Recently biodiesel has drawn much attraction as renewable enegy due to its environmental benefits and the fact that it is made from renewable resources. However, the production cost of biodiesel is one of the main hurdle to commercialize it. One of the way to reduce the biodiesel production cost is to use the waste cooking oil as feedstock. In the conventional transesterification process of waste cooking oils for biodiesel production, the presence of free fatty acids and water causes severe problems such as formation of soap and decreasing of catalyst yield. Much effort has been devoted to solve the above problems and one of the promising way is the supercritical methanol treatment which is performed at the methanol supercritical environment (>239.45oC, >8.10 Mpa)one of the serious problems of the application of SCM process for the biodiesel production is the tough operation condition(high pressure, high temperature. In this study, we have studied about the supercritical methanol treatment for the biodiesel production with the soybean waste cooking oil as a feedstock in the present of various heterogeneous solid catalysts such as mesoporous silica and acid-doped mesorpous silica. Biodiesel conversion was increased at more mild opreation condition to the previous studies by using the catalysts. The conversion was more enhanced by modifying the catalysts.

Polyurethane foam coated with a multi-walled carbon nanotube/polyaniline nanocomposite for a skin-like stretchable array of multi-functional sensors

Hong, Soo Yeong,Oh, Ju Hyun,Park, Heun,Yun, Jun Yeong,Jin, Sang Woo,Sun, Lianfang,Zi, Goangseup,Ha, Jeong Sook Nature Publishing Group 2017 NPG Asia Materials Vol.9 No.11

<P>Body-attachable sensors can be applied to electronic skin (e-skin) as well as safety forewarning and health monitoring systems. However, achieving facile fabrication of high-performance, cost-effective sensors with mechanical stability in response to deformation due to body movement is challenging. Herein we report the material design, fabrication and characteristics of a skin-like stretchable array of multi-functional (MF) sensors based on a single sensing material of polyurethane foam coated with multi-walled carbon nanotube/polyaniline nanocomposite, which enables simultaneous detection of body temperature, wrist pulse and ammonia gas. These sensors exhibit high sensitivity, fast response and excellent durability. Furthermore, the fabricated sensor array shows stable performance under biaxial stretching up to 50% and attachment to skin owing to the use of direct-printed Galinstan liquid metal interconnections. This work proposes a facile method for fabrication of high-performance, stretchable MF sensors via appropriate selection of sensor design and functional materials that are applicable to e-skin and health monitoring systems.</P>

Recent advances in refeeding syndrome in critically ill patients: a narrative review

( Sang Woo Ha ),( Suk-kyung Hong ) 한국정맥경장영양학회 2024 한국정맥경장영양학회지 Vol.16 No.1

Purpose: The aim of this article is to provide a narrative review of the most recent studies on refeeding syndrome (RS) in critically ill patients and to summarize recent advancements that can be referenced in the treatment of these patients. Current concept: RS in critically ill patients is a potentially lethal nutrition-related condition leading to sudden death. Initiation of food intake after a period of fasting can trigger rapid electrolyte uptake due to increased insulin release, leading to a decline in serum electrolytes with thiamine. This depletion may cause severe complications, such as cardiac arrhythmias, respiratory failure, seizures, and even death. The incidence of RS varies significantly, ranging from 7.4%-89%. Despite updates in diagnostic criteria over time, there remains a crucial need for criteria applicable to critically ill patients with underlying disorders such as metabolic derangement and organ dysfunction. To prevent RS, it is strongly recommended to start food intake after a fast at 20%-25% of estimated goals, gradually increasing the intake over several days. Close monitoring and electrolyte supplementation―especially of phosphorus, potassium, magnesium, and thiamine―are crucial, especially in critically ill patients. If electrolyte imbalances persist, slowing down or halting the progression of nutrition should be considered. Conclusion: Clinicians should continue their efforts to promptly identify high-risk patients and to provide prevention and treatment for RS, particularly during the initiation of nutritional therapy in critically ill patients. Developing evidence-based protocols through further well-designed research is essential for effectively managing critically ill patients at risk of RS.

The geometric effect of an off-centered cross-section on nickel–titanium rotary instruments: A finite element analysis study

Ha, Jung-Hong,Kwak, Sang Won,Versluis, Antheunis,Lee, Chan-Joo,Park, Se-Hee,Kim, Hyeon-Cheol Association for Dental Sciences of the Republic of 2017 Journal of Dental Sciences Vol.12 No.2

<P><B>Background/purpose</B></P><P>Geometric design dictates the mechanical performance of nickel–titanium rotary instruments. Using finite element (FE) analysis, this study evaluated the effects of an off-centered cross-sectional design on the stiffness and stress distribution of nickel–titanium rotary instruments.</P><P><B>Materials and methods</B></P><P>We constructed three-dimensional FE models, using ProTaper-NEXT type design (PTN) as well as three other virtual instruments with varied cross-sectional aspect ratios but all with the same cross-sectional area. The cross-sectional aspect ratio of the PTN was 0.75, while others were assigned to have ratios of 1.0 (square), 1.5 (rectangle), and 2.215 (centered-rectangle). The PTN center of the cross-section was ‘<I>k</I>’, while others were designed to have 0.9992<I>k</I>, 0.7<I>k</I>, and 0 for the square, rectangle, and centered-rectangle models, respectively. To compare the stiffness of the four FE models, we numerically analyzed their mechanical response under bending and torque.</P><P><B>Results</B></P><P>Under the bending condition, the square model was found to be the stiffest, followed by the PTN, rectangle, and then the centered-rectangle model. Under the torsion, the square model had the smallest distortion angle, while the rectangular model had the highest distortion angle.</P><P><B>Conclusion</B></P><P>Under the limitation of this study, the PTN type off-centered cross-sectional design appeared the most optimal configuration among the tested designs for high bending stiffness with cutting efficiency while rotational stiffness remained similar with the other designs.</P>

Acute gastric volvulus treated with laparoscopic reduction and percutaneous endoscopic gastrostomy

Sang-Ho Jeong,Chang-Youn Ha,Young-Joon Lee,Sang-Kyung Choi,Soon-Chan Hong,Eun-Jung Jung,Young-Tae Ju,Chi-Young Jeong,Woo-Song Ha 대한외과학회 2013 Annals of Surgical Treatment and Research(ASRT) Vol.85 No.1

Acute gastric volvulus requires emergency surgery, and a laparoscopic approach for both acute and chronic gastric volvulus was reported recently to give good results. The case of a 50-year-old patient with acute primary gastric volvulus who was treated by laparoscopic reduction and percutaneous endoscopic gastrostomy is described here. This approach seems to be feasible and safe for not only chronic gastric volvulus, but also acute gastric volvulus.