• 한국초전도저온공학회:학술대회논문집
• /
• 한국초전도저온공학회 2002년도 학술대회 논문집
• /
• pp.339-339
• /
• 2002

In the RABiTS approach to coated conductor development, successful (both economic and technological) depends on the refinement and optimization of each of three important components: the metal tape substrate, the buffer layer(s), and the HTS layer. Here we will report on the ORNL approach and progress in each of these areas. - Most applications will require metal tapes with low magnetic hysteresis, mechanical strength, and excellent crystalline texture. Some of these requirements are competing. We report on progress in obtaining a good combination of these characteristics on metal alloys of Ni-Cr and Ni-W. - The deposition of appropriate buffer layers is a crucial step. Recently, base research has shown that the presence of a stable sulfur superstructure present on the metal surface is needed for the nucleation and epitaxial growth of vapor-deposited seed buffer layers such as YSZ, CeO$_2$ and SrTiO$_3$. We report on the details and control of this superstructure for nickel tapes, as well as recent results for Cu and Ni-13%Cr. - Processes for deposition of the HTS coating must economically provide large values of the figure-of-merit for conductors, current x length. At ORNL, we have devoted efforts to a precursor/post-annealing approach to YBCO coatings, for which the deposition and reaction steps are separate. We describe motivation for and progress toward developing this approach. - Finally, we address some issues for the implementation of coated conductors in real applications, including the need for texture control and electrical stabilization of the HTS coating.

• 한국표면공학회지
• /
• 제34권5호
• /
• pp.403-408
• /
• 2001

In this work, the cyclic perfluorinated ether (c-C$_4$F$_{8}$O) with very high destructive removal efficiency (DRE) than other alternative gases, such as $C_3$F$_{8}$, c-C$_4$F$_{8}$ and NF$_3$ was used as an alternative process chemical. The plasma cleaning of silicon nitride using gas mixtures of c-C$_4$F$_{8}$O/O$_2$ and c-C$_4$F$_{8}$O/O$_2$+ $N_2$ was investigated in order to evaluate the effects of adding $N_2$ to c-C$_4$F$_{8}$O/O$_2$ on the global warming effects. Under optimum condition, the emitted net perfluorocompounds (PFCs) during cleaning of silicon nitride were quantified and then the effects of additive $N_2$ by obtaining the destructive removal efficiency (DRE) and the million metric tons of carbon equivalent (MMT-CE) were calculated. DRE and MMTCE were obtained by evaluating the volumetric emission using. Fourier transform-infrared spectroscopy (FT-IR). During the cleaning using c-C$_4$F$_{8}$O/O$_2$+$N_2$, DRE values as high as (equation omitted) 98% were obtained and MMTCE values were reduced by as high as 70% compared to the case of $C_2$F$_{6}$O$_2$. Recombination characteristics were indirectly investigated by combining the measurements of species in the chamber using optical emission spectroscopy (OES), before and after the cleaning, in order to understand any correlation between plasma and emission characteristics as well as cleaning rate of silicon nitride.silicon nitride.

• Nuclear Engineering and Technology
• /
• 제55권7호
• /
• pp.2662-2669
• /
• 2023

For the precise measurements of special nuclear materials (SNM) including Pu and Am isotopes, we have used phoswich detector combination of two single crystal scintillators of Gd₃Ga₃Al₂O₁₂:Ce and CsI:Tl. High detection efficiency and sensitivity along with high figure of merit for the discrimination of these phoswich detectors ensures the detection and discrimination of thermal neutrons and gammas from spontaneous fission of Pu and other isotopes in presence of high gamma background. Using this detector, the low energy gammas, which is stopped completely in 1mm thick disc of GGAG, can be also discriminated from high energies gamma and shows linearity in wide range of sample quantities. By changing only the appropriate shielding, the similar setup was used for thermal neutron detection and shows a very good linearity over wide range. The quantity of a test sample was also calculated accurately by using the measured calibrated plot.

• 한국수자원학회:학술대회논문집
• /
• 한국수자원학회 2022년도 학술발표회
• /
• pp.107-107
• /
• 2022

소하천의 홍수 예측은 대부분 수치모형을 직접 활용하거나, 미리 설정된 시나리오에 기반하여 수치모의를 수행하고 계산된 결과를 이용하여 추정한 경험식을 활용한다. 수치모형과 그 결과를 홍수 예·경보에 활용하기 위해서는 계측자료에 기반하여 변수를 최적화하는 등의 수치모형 검증절차가 매우 중요하다. 소하천은 국가, 지방하천에 비해 계측자료가 절대적으로 부족한 형편으로 소하천의 홍수 모의를 위해서 주로 국가, 지방하천에서 계측한 자료를 이용하여 검증을 수행한다. 이렇게 검증된 소하천 수치모형은 국가 혹은 지방하천 유역 전체를 모의하여야 하므로 모의시간이 많이 소요되어 1시간내에 홍수유출이 이루어지는 소하천 홍수 모의에는 적절치 않다. 또한 소하천은 하천경사가 급하고 유속이 빨라 실시간 홍수모의가 어려울 수 있다. 따라서 소하천의 홍수 예측방법으로 수치모형 보다는 계측자료에 기반한 추정삭이 보다 더 효율적이다. 행정안전부와 국립재난안전연구원은 2017년부터 소하천 홍수 예측기술 개발을 위하여 자동유량계측기술을 소하천에 확대적용하고 실시간 수리량 자료를 계측하고 있다. 자동유량계측기술은 CCTV를 이용하여 표면유속을 구하고 동시에 계측된 수위와 단면자료를 이용하여 자동으로 유량을 계측하는 기술이다. 자동유량계측기술은 저비용, 저노동, 고효율의 유량계측기술로써 부족한 계측인력과 계측의 안전성을 고려할 때 소하천에 적합한 계측기솔이라고 할 수 있다. 행정안전부와 국립재난안전연구원은 2025년 까지 전국 소하천의 10%인 2,230개 소하천에 자동유량계측기술을 확대 구축하고 실시간으로 수리량 자료를 걔측할 계획이다. 본 연구에서는 이들 계측자료와 AI 등 첨단기술에 기반한 홍수 예측기술 개발하고자 한다. 예측기술은 계측유역과 미계측유역을 구분하며, 계측유역에 대해서는 계측자료를 이용하고 미계측 유역에 대해서는 단위도법과 CES를 이용하여 구한 결과를 이용하여 강우-유량 노모그래프와 수위-유량 관계식을 개발한다. 이때 노모그래프는 토양수분조건을 고려하여 개발하며, 미계측 소하천의 예측결과는 소하천을 그룹화하고 동일 그룹내에 포함된 소하천의 계측자료를 이용하여 검증한다. 개발된 홍수 예측기술은 소하천 홍수 예·경보시스템에 적용되며 이렇게 개발된 시스템은 소하천의 인명피해 저감에 크게 기여할 수 있을 것으로 기대된다.

• 운동영양학회지
• /
• 제13권1호
• /
• pp.37-44
• /
• 2009

The purpose of this study was to investigate the change of bone metabolic parameters between climbing exercise training and treadmill running training with alpha lipoic acid supplementation in ovariectomized rats. Fifty-six Sparague-Dawley, 8 weeks of age, were assigned into nine groups: normal control at pre-test (Pre-NC), normal control at post-test (NC), sham-sedentary (SS), ovariectomized-control (OVX-Con), ovariectomized-ALA inject (OVX-ALA), ovariectomized-climbing exercise (OVX-CE), ovariectomized-ALA inject+climbing exercise (OVX-ACE), ovariectomized-treadmill exercise (OVX-TE) and ovariectomized-ALA inject+treadmill exercise (OVX-ATE). The climbing exercise group voluntarily climbed the 200 cm tower to drinking water from the bottle set at the top of it. The treadmill exercise group was performed the 60 min treadmill running with grade 6-8%, and velocity 10-15 m/min. The frequency of exercise training was performed 6 days per wk in both training intervention. For the comparison of bone metabolic responses following to different training intervention, the strength, length and weight of femur, total bone density, bone mineral contents, deoxypyridioline, osteocalcin and parathyroid hormone, estradiol and lutenizing hormone were measured in this study. The body weight was higher in the OVX-Con, OVX-ALA and OVX-TE groups as compared to NC group. The total bone mineral density of OVX-ACE showed a higher value than SS, OVX-Con, OVX-ATE and OVX-TE. But urine and blood metabolic parameters showed no significance among groups. In conclusion, this study results suggested that climbing exercise training and alpha lipoic acid supplementation may an effective intervention for prevention of osteoporosis in ovriectomized rats.

• 한국수소및신에너지학회논문집
• /
• 제34권6호
• /
• pp.587-593
• /
• 2023

This research project focused on the production of hydrogen through ammonia decomposition reactions while investigating how the reactivity of this process varies when employing different catalysts. Several metal oxide supports (Al₂O₃, La₂O₃, CeO₂) were utilized as catalysts, with active metals from both the transition metal group (Co, Ni, Fe, Cr, Cu) and the noble metal group (Ru, Rh, Pd, Pt) impregnated onto these supports. Furthermore, the study examined how the reactivity evolves with changes in reaction temperature when employing the prepared catalysts. Additionally, the research delved into the distinctive activation energies associated with each of the catalysts. In this research, In the noble metal catalyst system, the order of high activity for ammonia decomposition reaction to produce hydrogen is Ru > Rh > Pt ≈ Pd. In the transition metal catalyst system, the order of high activity is Co > Ni > Fe > Cr > Cu.

• Nuclear Engineering and Technology
• /
• 제56권2호
• /
• pp.745-752
• /
• 2024

A method for gamma/neutron event classification based on frequency-domain analysis for mixed radiation environments is proposed. In contrast to the traditional charge comparison method for pulse-shape discrimination, which requires baseline removal and pulse alignment, our method does not need any preprocessing of the digitized data, apart from removing saturated traces in sporadic pile-up scenarios. It also features the identification of neutron events in the detector's full energy range with a single device, from thermal neutrons to fast neutrons, including low-energy pulses, and still provides a superior figure-of-merit for classification. The proposed frequency-domain analysis consists of computing the fast Fourier transform of a triggered trace and integrating it through a simplified version of the transform magnitude components that distinguish the neutron features from those of the gamma photons. Owing to this simplification, the proposed method may be easily ported to a real-time embedded deployment based on Field-Programmable Gate Arrays or Digital Signal Processors. We target an off-the-shelf detector based on a small CLYC (Cs2LiYCl6:Ce) crystal coupled to a silicon photomultiplier with an integrated bias and preamplifier, aiming at lightweight embedded mixed radiation monitors and dosimeter applications.

• Clinical Endoscopy
• /
• 제56권3호
• /
• pp.367-374
• /
• 2023

Background/Aims: Endoscopic ultrasound (EUS)-guided fine-needle aspiration (FNA) using oblique-view EUS in patients with a surgically altered anatomy (SAA) of the upper gastrointestinal tract is limited because of difficult scope insertion due to the disturbed anatomy. This study aimed to investigate the efficiency of forward-view (FV)-EUS in performing FNA in patients with a SAA. Methods: We retrospectively investigated 32 patients with a SAA of the upper gastrointestinal tract who visited Aichi Cancer Center Hospital in Nagoya, Japan, between January 2014 and December 2020. We performed upper gastrointestinal EUS-FNA using FV-EUS combined with fluoroscopic imaging to confirm tumor recurrence or to make a decision before chemotherapy or after a failure of diagnosis by radiology. Results: We successfully performed EUS-FNA in all studied patients (100% technical success), with the specificity, sensitivity, and accuracy of 100%, 87.5%, and 87.8%, respectively, with no complications. Conclusions: EUS-FNA using FV-EUS combined with fluoroscopic imaging is an effective and safe technique for tissue acquisition in patients with a SAA.

• Clinical Endoscopy
• /
• 제56권1호
• /
• pp.55-64
• /
• 2023

Background/Aims: Endoscopic submucosal dissection (ESD) has been established as a treatment modality for superficial esophageal squamous cell carcinoma (ESCC). Long-term follow-up data are lacking in Western countries. The aim of this study was to analyze long-term survival in a Western center. Methods: Patients undergoing ESD for ESCC were included. The analysis was performed retrospectively using a prospectively collected database. Results: R0 resection rate was 96.7% (59/61 lesions in 58 patients). Twenty-seven patients (46.6%) fulfilled the curative resection criteria (M1/M2) (group A), 11 patients (19.0%) had M3 lesions without lymphovascular invasion (LVI) (group B), and 20 patients (34.5%) had lesions with submucosal invasion or LVI (group C). Additional treatment was recommended after non-curative resection. It was not performed in 20/31 patients (64.5%), mainly because of comorbidities (75%). Twenty-nine out of 58 (50.0%) patients died during a mean follow-up of 3.7 years. Death was related to ESCC in 17.2% (5/29) of patients. The disease-specific survival rate after curative resection was 100%. Overall survival rates after 5 years were 61.5%, 63.6% and 28.1% for groups A, B, and C, respectively. The overall survival was significantly worse after non-curative resection (p=0.038). Conclusions: Non-curative resection is frequent after ESD for ESCC in Western patients. The long-term prognosis is limited and mainly determined by comorbidity. Early diagnosis and pre-interventional assessments need to be improved.

• Clinical Endoscopy
• /
• 제56권2호
• /
• pp.188-193
• /
• 2023

Background/Aims: Data on the incidence of adverse respiratory events during recovery from gastrointestinal endoscopy are limited. The aim of this study was to investigate the incidence of these complications. Methods: In this retrospective cohort study, data were obtained from the electronic records of 657 consecutive patients, who underwent gastroenterological procedures under sedation. Results: Pulse oximetry oxygen saturation (SpO₂) <90% for <60 seconds occurred in 82 patients (12.5%), and in 11 patients (1.7%), SpO₂ of <90% for >60 seconds occurred in 79 patients (12.0%) and in 14 patients (2.1%), and SpO₂ <75% occurred in four patients (0.6%) and in no patients during the procedure and recovery period, respectively. No major complications were noted. The occurrence of desaturation during recovery was correlated with desaturation during the procedure (p<0.001). Higher American Society of Anesthesiologists score (odds ratio [OR], 1.867; 95% confidence interval [CI], 1.008-3.458), ischemic heart disease (OR, 1.815; 95% CI, 0.649-5.080), hypertension (OR, 1.289; 95% CI, 0.472-3.516), and diabetes mellitus (OR, 2.406; 95% CI, 0.950-6.095) increased the occurrence of desaturation during recovery. Conclusions: We found no major complications during recovery after balanced propofol-based sedation administered by a gastroenterologist-nurse team. Patients with the identified risk predictors must be monitored carefully.