• 센서학회지
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• 제21권4호
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• pp.283-286
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• 2012

This paper presents the optical hydrogen sensor based on transparent 3C-SiC membrane and photovoltaic effect. Gasochromic materials of Pd and Pd/$WO_3$ were deposited by sputter on 3C-SiC membrane for gas sensing area. Gasochromic materials change to transparency by exposure to hydrogen. The variations of light intensity by hydrogen generate the photovoltaic of P-N junction between N-type 3C-SiC and P-type Si. Single layer of Pd shows higher photovoltaic compared with Pd/$WO_3$. However, phase transition from ${\alpha}$ to ${\beta}$ is shown at 6 %. Pd/$WO_3$ structure show the more linear response to hydrogen range of 2 % ~10 %. Also, almost 2 times fast response and recovery characteristics are shown at Pd/$WO_3$. These fast performances are come from the fact that Pd promoted the chemical reaction between hydrogen and $WO_3$.

• 한국막학회:학술대회논문집
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• 한국막학회 1999년도 The 7th Summer Workshop of the Membrane Society of Korea
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• pp.43-47
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• 1999

Pd-ceramic composite membranes and catalytic membrane reactors(CMR) have been studied for hydrogen purification and recovery in th fusion reactor fuel cycle. The development of techniques for coating microporous ceramic tubes with Pd and Pd/Ag layers is described: composite membranes have been produced by electroless deposition (Pd/Ag film of 10-20${\mu}{\textrm}{m}$) and rolling of thin metal sheet (Pd and Pd/ Ag membranes of 50-70 ${\mu}{\textrm}{m}$). Experimental results on electroless membranes showed that the metallic film presented some defects and the membranes had not complete hydrogen selectivity . Then the catalytic membrane reactors with electroless membranes can be applied for some industrial processes that do not require a complete separation of the hydrogen (i.e. in the dehydrogenation of hydrocarbons). The rolled thin Pd/Ag membranes separated the hydrogen from the other gas with a complete selectivity and exhibited a slightly larger (about a factor 1.7) mass transfer resistance with respect to the electroless membranes. Experimental tests confirmed the good performances in terms of durability.

• 대한의생명과학회지
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• 제3권2호
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• pp.169-175
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• 1997

닭의장풀 추출액을 쥐의 체중 1 kg 당 40 mg의 alloxan을 미정맥 주사한 당뇨쥐를 실험군으로 하여 혈당강하효과를 보았다. 정상대조군에게는 0.9% saline용액을 투여하고 당뇨쥐에게는 쥐의 체중 1 kg당 100 mg의 식물단백추출액을 경구투여하여 683.6$\pm$115.61 (mg/dl)에서 85.6$\pm$43.34 (mg/dl)의 혈당치의 정상수준으로 회복하는 경향을 확인하였다. 정상군과 당뇨대조군, 약물투여군으로 나눈 실험쥐를 대상으로 간조직에서의 glucose-6-phosphate dehydrogenase (G6PD) 효소의 활성도를 측정한 결과 당뇨대조군에서는 정상군의 34.2%로 G6PD 효소 활성도가 감소되었으며 식물추출액을 투여함으로써 정상치의 61%로 회복되었다. 실험쥐 간조직내에 G6PD효소활성도의 감소 또는 회복과 G6PD isozyme분자의 구조변화와의 연관성을 알아보기 위하여 native gel 전기영동을 실시하였다. 정상쥐의 간조직에서의 G6PD isozyme형태는 band I, II, III(전기영동상의 분자이동 차이에 따른 형태)로 나타났고 alloxan을 투여한 당뇨쥐의 간조직내에서는 band I, III만이 나타났다. 닭의장풀 추출액을 투여 한 실험 군에서는 G6PD의 isozyme 형태가 정상쥐의 경우에서와 같이 band I, II와 III가 모두 나타났다. 이러한 결과는 G6PD isozyme의 구조변화가 G6PD의 효소활성도와 매우 큰 연관성이 있는 것으로 보여진다.

• ETRI Journal
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• 제45권1호
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• pp.105-118
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• 2023

We tested the feasibility of automated discrimination of patients with panic disorder (PD) from healthy controls (HCs) based on multimodal physiological responses using machine learning. Electrocardiogram (ECG), electrodermal activity (EDA), respiration (RESP), and peripheral temperature (PT) of the participants were measured during three experimental phases: rest, stress, and recovery. Eleven physiological features were extracted from each phase and used as input data. Logistic regression (LoR), k-nearest neighbor (KNN), support vector machine (SVM), random forest (RF), and multilayer perceptron (MLP) algorithms were implemented with nested cross-validation. Linear regression analysis showed that ECG and PT features obtained in the stress and recovery phases were significant predictors of PD. We achieved the highest accuracy (75.61%) with MLP using all 33 features. With the exception of MLP, applying the significant predictors led to a higher accuracy than using 24 ECG features. These results suggest that combining multimodal physiological signals measured during various states of autonomic arousal has the potential to differentiate patients with PD from HCs.

• 대한금속재료학회지
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• 제48권4호
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• pp.342-346
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• 2010

Pd nanoparticles (NPs) were successfully functionalizedon the surfaces of single-walled carbon nanotubes (SWNTs) by dendrimer-mediated synthesis. The hydrogen sensing properties of the Pd NPs functionalized SWNTs were investigated. Pd NPs-dendrimer-SWNTs sensors show much better speedsand superior recovery rates but lower sensitivity compared to Pd NPs-functionalized SWNTs directly fabricated due to the existence of dendrimers. Pyrolysis of the dendrimers by heat treatment resulted in a fast response time and high sensitivity owing to the reduced length of the dendrimers. These results demonstrate that the heat treatment of dendrimers in Pd NPs-dendrimer-SWNTs sensors can enable significant electrical conductance modulation upon exposure to extremely low concentrations (10 ppm) of hydrogen gas ($H_2$) in air.

• Bulletin of the Korean Chemical Society
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• 제33권8호
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• pp.2539-2545
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• 2012

In the present study, we suggest a new way to reactivate performance of direct formic acid fuel cell (DFAFC) and explain its mechanism by employing electrochemical analyses like chronoamperometry (CA) and cyclic voltammogram (CV). For the evaluation of DFAFC performance, palladium (Pd) and platinum (Pt) are used as anode and cathode catalysts, respectively, and are applied to a Nafion membrane by catalyst-coated membrane spraying. After long DFAFC operation performed at 0.2 and 0.4 V and then CV test, DFAFC performance is better than its initial performance. It is attributed to dissolution of anode Pd into $Pd^{2+}$. By characterizations like TEM, Z-potential, CV and electrochemical impedance spectroscopy, it is evaluated that such dissolved $Pd^{2+}$ ions lead to (1) increase in the electrochemically active surface by reduction in Pd particle size and its improved redistribution and (2) increment in the total oxidation charge by fast reaction rate of the Pd dissolution reaction.

• 대한전자공학회논문지SD
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• 제43권10호
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• pp.28-33
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• 2006

본 논문은 시리얼 링크를 위한 레퍼런스 클록이 없고 4x 오버샘플링 방식의 위상 및 주파수 검출기 구조를 갖는 하프 레이트 클록 및 데이터 복원 회로를 제안하였다. 위상 검출기는 4개의 업/다운 신호를 생성함으로써 위상 에러를 검출하고, 주파수 검출기는 위상 검출기 출력에 의해 만들어진 업/다운 신호를 이용하여 주파수 에러를 검출한다. 그리고 위상 검출기와 주파수 검출기의 여섯 개 신호는 전하 펌프로 흘러 들어가는 전류의 양을 조절한다. 네 개의 차동 버퍼로 구성된 VCO는 4x 오배샘플링을 위한 8개의 클록을 생성한다. 0.18um CMOS 공정을 사용하였고, 실험 결과 제안된 회로는 3.125Gbps의 속도로 클록과 데이터를 복원해 낼 수 있었다. 제안된 구조의 PD와 FD를 사용하여 24%의 넓은 트래킹 주파수 범위를 가진다. 측정된 클록의 지터(p-p)는 약 14ps였다. CDR은 1.8v의 단일 전원 공급기를 사용하였고, 전력소모는 약 140mW이다.

• 한국간담췌외과학회지
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• 제28권1호
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• pp.80-91
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• 2024

Backgrounds/Aims: Optimal intravenous fluid management during the perioperative period for patients undergoing pancreaticoduodenectomy (PD) within the framework of enhanced recovery after surgery (ERAS) is unclear. Studies have indicated that excessive total body salt and water can contribute to the development of oedema, leading to increased morbidity and extended hospital stays. This study aimed to assess the effects of an intravenous therapy regimen during postoperative day (POD) 0 to 2 in PD patients within ERAS. Methods: A retrospective interventional cohort study was conducted, and it involved all PD patients before and after implementation of ERAS (2009-2017). In the ERAS group, a targeted maintenance fluid regimen of 20 mL/kg/day with a sodium requirement of 0.5 mmoL/kg/day was administered. Outcome measures included the mmol of sodium and chloride administered, length of stay, and morbidity (postoperative pancreatic fistula, POPF; acute kidney injury, AKI; ileus). Results: The study included 169 patients, with a mean age of 64 ± 11.3 years. Following implementation of the intravenous fluid therapy protocol, there was a significant reduction in chloride and sodium loading. However, in the multivariable analysis, chloride administered (mmoL/kg) did not independently influence the length of stay; or rates of POPF, ileus, or AKI (p > 0.05). Conclusions: The findings suggested that a postoperative intravenous fluid therapy regimen did not significantly impact morbidity. Notably, there was a trend towards reduced length of stay within an increasingly comorbid patient cohort. This targeted fluid regimen appears to be safe for PD patients within the ERAS program. Further prospective research is needed to explore this area.

• 대한금속재료학회지
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• 제48권2호
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• pp.148-153
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• 2010

The effects of Cu(II) and Al(III) on the extraction and separation of Pt(IV) and Pd(II) have been investigated in a mixed chloride solution using Alamine336 as the extractant. In the HCl concentration range of 1 to 5 M, more than 99% of Pt and Pd could be extracted by Alamine336 from all of the mixed chloride solutions investigated in this study. Lower HCl concentration led to a higher separation factor between Pd and Pt when Alamine336 concentration was constant. Extraction percentage of Cu increased with the increase of HCl concentration, while that of Al was nearly constant at 33% in our experimental range. The optimum conditions to extract Pt and Pd from Cu or Al and the separation factor under these conditions were obtained.

• 전자공학회논문지SC
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• 제46권2호
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• pp.72-77
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• 2009

본 논문은 별도 기준 클록 없이 고속 시리얼 데이터 통신을 위한 3.2Gb/s 클록 데이터 복원(CDR) 회로를 설명한다. CDR회로는 전체적으로 5부분으로 구성되며, 위상검출기(PD)와 주파수 검출기(FD), 다중 위상 전압 제어 발진기(VCO), 전하펌프(CP), 외부 루프필터(LF)로 구성되어 있다. CDR회로는 half-rate bang-bang 타입의 위상 검출기와 입력 pull-in 범위를 늘릴 수 있도록 half-rate 주파수 검출기를 적용하였다. VCO는 4단의 차동 지연단(delay cell)으로 구성되어 있으며 튜닝 범위와 선형성 향상을 위해 rail-to-rail 전류 바이어스단을 적용하였다 각 지연단은 풀 스윙과 듀티의 부정합을 보상할 수 있는 출력 버퍼를 갖고 있다. 구현한 CDR회로는 별도의 기준 클록 없이 넓은 pull-in 범위를 확보할 수 있으며 기준 클록 생성을 위한 부가적인 Phase-Locked Loop를 필요치 않기 때문에 칩의 면적과 전력소비를 효과적으로 줄일 수 있다. 본 CDR 회로는 0.18um 1P6M CMOS 공정을 이용하여 제작하였고 루프 필터를 제외한 전체 칩 면적은 $1{\times}1mm^2$이다. 3.2Gb/s 입력 데이터 율에서 모의실험을 통한 복원된 클록의 pk-pk 지터는 26ps이며 1.8V 전원전압에서 전체 전력소모는 63mW로 나타났다. 동일한 입력 데이터 율에서 테스트를 통한 pk-pk 지터 결과는 55ps였으며 신뢰할 수 있는 입력 데이터율 범위는 약 2.4Gb/s에서 3.4Gb/s로 나타났다.