• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2009년도 제38회 동계학술대회 초록집
• /
• pp.93-93
• /
• 2010

Semiconductor nanocrystal quantum dots (NQDs) have recently attracted considerable interest for use in photovoltaics. Band gaps of NQDs can be tuned over a considerable range by varying the particle size thereby allowing enhance absorption of solar spectrum. NQDs, synthesized using colloidal routes, are solution processable and promise for a large-area fabrication. Recent advancements in multiple-exciton generation in NQD solutions have afforded possible efficiency improvements. Various architectures have attempted to utilize the NQDs in photovoltaics, such as NQD-sensitized solar cell, NQD-bulk-heterojuction solar cell and etc. Here we have fabricated CdSe NQDs with the band gap of 1.8 eV to 2.1 eV on thin-layers of p-type organic crystallites (1.61 eV) to realize a donor-acceptor type heterojuction solar cell. Simple structure as it was, we could control the interface of electrode-p-layer, and n-p-layer and monitor the following efficiency changes. Specifically, surface molecules adsorbed on the NQDs were critical to enhance the carrier transfer among the n-layer where we could verify by measuring the photo-response from the NQD layers only. Further modifying the annealing temperature after the deposition of NQDs on p-layers allowed higher conversion efficiencies in the device.

• 한국연초학회지
• /
• 제16권1호
• /
• pp.3-13
• /
• 1994

To minimize the time ordinarily spent in mono filter cigarette design, we studied the relationship between major seven independant variables ; filament(X1) and total denier(X2), porosity of the aller plug wrap(X3), filter length(X4), Porosity of the tip paper(X5) and cigarette paper(X6) and net weight of the reference cut tobacco(X7). Ninty trial numbers were obtained as a results of using rotatable central composite design and it is analyzed by the multiple regression analysis with stepwise in SAS/pc under restricted conditions. That is, UPD (Y1) = 82.96 - 3.80X1 + 2.50X2 - 3.29X3 - 3.15X5 - 0.83X22 + 1.88X5X6 - 1.38 X5X7(R2: 0.63), EPD(Y2) : 120.91 - 5.70X1 + 3.60X2 + 4.23X4 - 0.93X6 + 4.06X7 (R2=0.84), TVR(Y3) = 49.70 - 0.78X1 + 3.60X3 + 2.00X4 + 4.20X5 - 0.93X6 + 2.64X7 - 1.07X1X2 + 1.0IX1 X3 + 1.05X2X6 + 0.45X22 - 0.64X42 + 1.29X4X6 - 0.97X4X7 - 1.28X5X6 + 1.53X5X7 + 1.39X6X7(R2=0.65), and EVR(Y4) : 3.24-0.21X3-0.20X4 -0.24X5+0.67X6+0.26X4X7 (R2=0.55), where EPD : encapsulated pressure drop, VPD : unencapsulated pressure drop, TVR ; tip ventilation rate, and En : envelope ventilation rate. All variables in the model are significant at the 0.05 level.

• 치위생과학회지
• /
• 제24권3호
• /
• pp.134-145
• /
• 2024

Background: Dental hygienists are crucial in managing infection control within dental clinical settings. This study focused on examining the pre-treatment infection control practices (PT-PRF_IC) of Korean dental hygienists in the context of coronavirus disease (COVID-19) and identifying factors influencing their implementation levels. Methods: An online, self-administered survey was conducted with 263 dental hygienists working in dental hospitals or clinics. The survey explored various aspects such as the experience with infection control education (Edu_IC), PT-PRF_IC, and the types of surface disinfectants used. Additionally, data from previous studies on the knowledge level of COVID-19 (KNW_CO), infection control awareness level (AWR_IC), infection control performance level (PRF_IC), and infection control organizational factor (OFW_IC) were utilized. Statistical analyses included t-tests, one-way ANOVA, chi-square tests, Pearson correlation, and multiple linear regression. Results: The study identified variations in PT-PRF_IC based on the number of dental hygienists within an organization. Differences in Edu_IC were observed concerning age, number of years worked, and monthly pay. The OFW_IC had the most substantial impact on PT-PRF_IC, followed by PRF_IC, and AWR_IC. Conclusion: To improve compliance with PT-PRF_IC, it is essential to consider a combination of factors including OFW_IC, PRF_IC, and AWR_IC. Strengthening organizational factors and awareness can enhance infection control practices and prevent COVID-19 transmission during dental care.

• 청정기술
• /
• 제28권1호
• /
• pp.79-93
• /
• 2022

본 연구에서는 Part I에서 제안한 첨단 전자산업 폐수처리시설 특화 Water Digital Twin모델인 e-ASM을 이용하여 랩-파일럿 처리장 데이터를 바탕으로 모델 보정(Calibration), 유입 성상에 따른 제거 효율, 유출수 예측 및 최적 공법 선정을 수행하였다. 첨단 전자산업 폐수처리시설의 특화 모델링을 위하여, 민감도 분석을 통해 e-ASM 모델의 정합성과 상관성이 높은 동역학적 파라미터를 선정하였고, 다중반응표면분석법 (Multiple response surface methodology, MRS)을 이용하여 동역학적 파라미터를 보정하였다. e-ASM 모델의 보정 결과, Lab-scale, Pilot-scale 단위의 실험데이터와 90% 이상의 높은 정합성을 보였다. 그리고 4가지 유기폐수 처리처리공법인 MLE, A2/O, 4-stage MLE-MBR, Bardenpho-MBR을 제안한 Water Digital Twin으로 구현하여 유입 폐수의 성상별 운전조건에 따라 제거효율을 분석하였으며, Bardenpho-MBR이 C/N ratio 변화에서도 안정적으로 COD (Chemical oxygen demand)를 90% 이상 제거하며 높은 총 질소 제거 효율을 보였다. 그리고 유입 폐수의 조건별 Bardenpho-MBR공정의 수리학적 체류시간(Hydraulic retention time, HRT)이 3일 이상일 때 1,800 mg L-1의 고농도 TMAH 폐수를 98% 이상 제거할 수 있음을 확인할 수 있었다. 이와 같이, 본 연구에서 개발한 e-ASM은 전자산업 제조시설별, 유입 폐수의 성상별 특화 모델링을 통해 높은 정합성을 가진 전자산업 폐수처리공정의 Water Digital Twin를 구현할 수 있고, 최적운전, Water AI, 최적가용기법 선정 등의 응용 가능성을 바탕으로 지속 가능한 첨단전자 산업을 위해 활용될 수 있을 것으로 사료된다.

• 생명과학회지
• /
• 제34권6호
• /
• pp.418-425
• /
• 2024

고형암은 여러 세포 유형의 이질적인 집단으로 구성되며, 암줄기세포는 자가 재생과 분화의 특성을 가지고 있다. 암줄기세포에서는 자가재생을 조절하는 줄기세포 신호전달체계가 과도하게 활성화되어 있어 암줄기세포는 암세포의 증식과 암 진행에 중요하다. 암줄기세포의 정의는 급성골수성백혈병에 의해 처음 제안되었으며, 다양한 연구를 통해 세포 표면 표지 발현에 따라 암 줄기세포를 분류할 수 있게 되었다. 또한, 암줄기세포는 종양 미세환경에서 잠재력을 보존하고 있고, 다양한 종양 미세환경 세포 유형은 정지 상태의 암줄기 세포를 유지하고 암 성장의 조절자 역할을 한다. 현재 사용되는 암 치료 방법은 증식성 세포를 표적으로 하기 때문에 치료에, 저항성을 가지는 휴지기 상태의 암 줄기세포는 재발이나 전이의 위험을 증가시키며, 종양 미세환경의 다양한 신호전달체계는 혈관계와 세포 외 기질을 리모델링함으로써 종양 지지 환경으로의 변화를 유도한다. 따라서, 암을 효과적으로 치료하려면 암줄기세포와 종양 미세환경을 표적 치료해야 하며, 종양 미세환경이 어떻게 면역 반응의 재프로그램을 유도하여 암의 성장, 면역 저항성 및 전이를 촉진하는지 이해하는 것이 중요하다. 따라서 본 총설을 통해 종양 미세환경에서 면역억제를 강화할 수 있는 세포 및 분자 메커니즘에 대한 현재 및 새로운 개념을 요약하고자 한다.

• 한국수산과학회지
• /
• 제49권3호
• /
• pp.301-309
• /
• 2016

To facilitate the effective use of butter clam shell as a natural calcium resource, we determined the optimal conditions for calcium lactate (BCCL) preparation with high solubility using response surface methodology (RSM). The polynomial models developed by RSM for pH, solubility and yield were highly effective in describing the relationships between factors (P<0.05). Increased molar ratios of calcined powder (BCCP) from butter clam shell led to reduced solubility, yield, color values and overall quality. The critical values of multiple response optimization to independent variables were 1.75 M and 0.94 M for lactic acid and BCCP, respectively. The actual values (pH 7.23, 97.42% for solubility and 423.22% for yield) under optimization conditions were similar to the predicted values. White indices of BCCLs were in the range of 86.70–90.86. Therefore, organic acid treatment improved color value. The buffering capacity of BCCLs was strong, at pH 2.82 to 3.80, upon the addition of less than 2 mL of 1 N HCl. The calcium content and solubility of BCCLs were 6.2–16.7 g/100 g and 93.6-98.5%, respectively. Fourier transform analysis of infrared spectroscopy data identified BCCL as calcium lactate pentahydrate, and the analysis of microstructure by field emission scanning electron microscopy revealed an irregular form.

• 한국식품과학회지
• /
• 제47권3호
• /
• pp.321-327
• /
• 2015

패류의 주된 가공부산물인 패각은 전체중량의 50% 이상을 차지하며, 그 주성분이 불용성의 탄산칼슘으로서, 이를 천연 칼슘 소재로 활용하기 위해 바지락 패각을 소성처리($800^{\circ}C$, 8시간)한 소성분말로부터 가용성 개선 유기산(초산)처리 칼슘제조의 최적 조건을 규명하고자 하였다. 반응표면 분석법의 중심합성계획에 따라 제조한 11개 초산칼슘의 pH, 용해도 및 수율로부터 구명한 최적 반응조건은 초산 2.57 M 비율에 대하여 바지락 소성분말 1.57M이었으며, 이의 최적조건을 적용한 바지락 초산칼슘의 실측 pH, 용해도 및 수율은 각각 pH 7.00, 96.09% 및 220.87%로서 예측치와 유사한 결과를 얻었다. 초산칼슘의 완충능은 pH 4.89-4.92 범위였으며, 초산칼슘의 칼슘함량은 22% 내외, 20% 초산칼슘의 용해도는 96.09-100.10% 범위였다. FT-IR, XRD 분석 및 FESEM을 통한 미세구조는 비정형과 관상형이 혼합된 결정으로서 calcium acetate monohydrate로 확인되었다. 바지락 패각은 칼슘소재로서 뿐만 아니라 가용성을 높인 유기산 칼슘으로 칼슘강화용 식품소재로서의 이용 가능성이 확인되었다.

• Translational and Clinical Pharmacology
• /
• 제26권4호
• /
• pp.160-165
• /
• 2018

Indobufen ($Ibustrin^{(R)}$), a reversible inhibitor of platelet aggregation, exists in two enantiomeric forms in 1:1 ratio. Here, we characterized the anti-platelet effect of S- and R-indobufen using response surface modeling using $NONMEM^{(R)}$ and predicted the therapeutic doses exerting the maximal efficacy of each enantioselective S- and R-indobufen formulation. S- and R-indobufen were added individually or together to 24 plasma samples from drug-naïve healthy subjects, generating 892 samples containing randomly selected concentrations of the drugs of 0-128 mg/L. Collagen-induced platelet aggregation in platelet-rich plasma was determined using a Chrono-log Lumi-Aggregometer. Inhibitory sigmoid $I_{max}$ model adequately described the anti-platelet effect. The S-form was more potent, whereas the R-form showed less inter-individual variation. No significant interaction was observed between the two enantiomers. The anti-platelet effect of multiple treatments with 200 mg indobufen twice daily doses was predicted in the simulation study, and the effect of S- or R-indobufen alone at various doses was predicted to define optimal dosing regimen for each enantiomer. Simulation study predicted that 200 mg twice daily administration of S-indobufen alone will produce more treatment effect than S-and R-mixture formulation. S-indobufen produced treatment effect at lower concentration than R-indobufen. However, inter-individual variation of the pharmacodynamic response was smaller in R-indobufen. The present study suggests the optimal doses of R-and S-enantioselective indobufen formulations in terms of treatment efficacy for patients with thromboembolic problems. The proposed methodology in this study can be applied to the develop novel enantio-selective drugs more efficiently.

• 한국수산과학회지
• /
• 제55권2호
• /
• pp.102-110
• /
• 2022

This study was conducted to optimize the processing process for the oyster Crassostrea gigas gratin with cream sauce (OG-CS). The optimum concentration of added milk for oyster extract with milk (OE-M) was 35.0% based on the frozen-boiled oyster (F-BO), as suggested by the results of sensory evaluation. Response surface methodology was performed with whipping cream (WC)/[OE-M+mixed powder (garlic powder:onion powder=1:1) (MP)] (X₁) and OE-M/MP (X₂) as independent variables and viscosity (Y₁), amino acid nitrogen (Y₂), and overall acceptance for sensory evaluation (Y₃) as dependent variables. The optimal proportions were 74.55% of WC, 20.25% of OE-M, and 5.2% of MP, and the predicted multiple response optimal values for the dependent variables were 3,735.6 cP of Y₁, 197.0 mg/100 g of Y₂, and 6.2 score of Y₃. Under optimal conditions, the experimental values for Y₁, Y₂, and Y₃ were 3,711.9±30.0 cP, 198.1±1.9 mg/100 g, and 6.3±0.5 score, respectively, which were not significantly different from the predicted values (P>0.05). Further, the results of sensory evaluation suggested that the optimum concentration of macaroni:cheese (1:2) to be 46.2% based on the F-BO. The OG-CS prepared under these optimal conditions was superior to the commercial seafood gratin in overall acceptance.

• 센서학회지
• /
• 제33권1호
• /
• pp.40-47
• /
• 2024

The creation of vertically aligned one-dimensional (1D) nanostructures through the decoration of n-type tin oxide (SnO₂) on p-type chromium oxide (Cr₂O₃) constitutes an effective strategy for enhancing gas sensing performance. These heterostructures are deposited in multiple stages using a glancing angle deposition technique with an electron beam evaporator, resulting in a reduction in the surface porosity of the nanorods as SnO₂ is incorporated. In comparison to Cr₂O₃ films, the bare Cr₂O₃ nanorods exhibits a response 3.3 times greater to 50 ppm H₂S at 300℃, while the SnO₂-decorated Cr₂O₃ nanorods demonstrate an eleven-fold increase in response. Furthermore, when subjected to various gases (CH₄, H₂S, CO₂, H₂), a notable selectivity toward H₂S is observed. This study paves the way for the development of p-type semiconductor sensors with heightened selectivity and sensitivity towards H₂S, thus advancing the prospects of gas sensor technology.