• 한국초전도ㆍ저온공학회논문지
• /
• 제20권4호
• /
• pp.36-40
• /
• 2018

In this study, the electromechanical properties in Sn-Cu double layer stabilized GdBCO coated conductor (CC) tapes with and without external lamination under uniaxial tension were examined at 77 K and self-field. Their irreversible stress and strain limits were determined using a loading-unloading scheme based on different critical current ($I_c$) recovery criteria. The repeated tests were performed and statistical estimation was done to check the reproducibility depending on the criterion adopted in evaluating the electromechanical properties. From the results, it showed that the Sn-Cu double-layer stabilized CC tapes have the higher irreversible stress limit, but lower irreversible strain limit as compared to brass laminated ones. Through the repeated tests, it can be found that a small scattering of irreversible limits existed in both CC tape samples. Finally, similar strain sensitivity of $I_c$ in both CC tapes was obtained.

• Journal of Biosystems Engineering
• /
• 제12권2호
• /
• pp.28-37
• /
• 1987

Operation of rice whiteners has been depending on operator's experience only and very limitted data are available for operational criteria of rice whiteners in Korea. With developments of new rice varieties and with a tendency of automation of machine operations for precision control, operational criteria depending on physical characteristics of rice grains arc required for an improvement of milled rice recovery and the performance of rice whitening systems. An experimental study was conducted to identify operational criteria of a rice whitening system consisted with an abrasive-aerated whitener developed newly and a frictional-aerated whitener being used commercially. Further, comparisons were made between the performance of the rice whitening system adopted for this study and a commercial system used in small scale milling plants. Results of this study are summarized as follows: 1. Total number of passes necessary for the final white rice in the combined whitening system depended exclusively on the counter pressure level of the frictional whitener successive to the abrasive whitener. 2. The counter pressure required for whitening Japonica type rice variety (Akibare) was higher by about 1.6 times than that for Japonica type (Pung-san), when other conditions were kept at the same. 3. Radial pressure in the whitening chamber of the frictional whitener should be maintained between 1.5 to $2.1kg/cm^2$ for the completion of whitening within 5 to 3 passes regardless of rice varieties. Hence, it was found that the radial pressure in the whitening chamber could be used as an operational criteria to control the counter pressure level. 4. The following regression equation was found between radial pressure($R_p$) in whitening chamber and electric power consumption of the whitening system: $$EPC=-0.545\;R^2_p+1.277\;R_p+0.874[KWH/100kg]$$ 5. The following multiple regression equation was found among radial pressure ($R_p$), counter pressure ($C_p$), and bioyield point ($B_i$), length (L) and width (W) of brown rice. $$R_p/(B_i/W^2)=0.547\{C_p/(B_i/W^2)\}^{0.365}(L/W)^{0.120}(R^2=0.9897)$$ 6. The milled rice recovery and machine efficiency (kg/KWH) from the combined whitening system were higher by about 2.0% point and by 15 to 27% point than those from the conventional system, respectively.

• 분석과학
• /
• 제36권5호
• /
• pp.205-215
• /
• 2023

In the present study, an analytical method was proposed for detecting trifluralin in aquatic products at trace concentrations. The method employed QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) and gas chromatography coupled with tandem mass spectrometry (GC-MS/MS) as the sample preparation and measurement, respectively. The effect of the aqueous phase volume used in the QuEChERS was demonstrated, and the ratio of 10:10 (mL) between water and acetonitrile phase was used for 5 g of sample. Besides, dSPE using C18 and primary-secondary amine (PSA) was applied to remove the potential interferences from the food matrices, indicating no remarkable analyte loss. The linear range was built up from 0.50 ㎍ L^-1 to 3.0 ㎍ L^-1 (R² = 0.9993). Other criteria, i.e., repeatability (RSD_r = 0.86-1.96 %), reproducibility (RSD_R = 1.09-2.01 %), and recovery (over 90 %), were in accordance with Appendix F of AOAC (2016) for method performance. Although no trifluralin was detected for the commercial samples (fish, shrimp, and breaded shrimp), the spiked samples performed favorable recoveries and precision.

• Applied Biological Chemistry
• /
• 제32권4호
• /
• pp.424-434
• /
• 1989

식품공장 폐수에는 각종 유기물을 다량 함유하고 있다. 이와 같은 식품공장 폐기물의 미생물학적 처리효과를 검토하는 동시에 폐수 중에서 배양된 곰팡이 균체 단백질을 분리 회수함으로 해서 폐수처리비용을 절검하고, 단백질 함량이 높은 균체단백사료를 개발할 목적으로 식품공장 폐수의 BOD 및 COD를 낮은 수준으로 감소시키고 증식속도가 빠르며 균체수율이 높고 고농도의 단백질을 함유하며 소화율이 높은 균체를 생산할 수 있는 곰팡이로 Aspergillus fumigatus를 분리 선발하였고, 선발된 균주의 최적배양조건인 $35{\sim}40^{circ}C,\;pH\;4.0{\sim}4.5$에서 pilot plant의 연속배양장치를 이용하여 주정공장 폐수를 기질로 하여 일정시간 동안 배양하여 폐수의 BOD, COD를 90% 이상 감소시켜 폐수정화를 도모할 수 있었으며 균체단백질을 기준 배합사료에 첨가하여 실시한 동물사양 시험 결과, 사양동물의 체중증가량과 단백질 이용율이 대조표준 시험구에 준할 수 있는 효과를 보여 주었다.