• 한국토양비료학회지
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• 제50권6호
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• pp.674-683
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• 2017

The frequency and intensity of soil moisture stress associated with climate change has increasing, and the stability of field crop cultivation has decreasing. This experiment was conducted to investigate the effect of soil moisture management method on growth and yield of corn. Soil moisture was managed at the grade of WSM (wet soil moisture, 34.0~42.9%), OSM (optimum soil moisture, 27.8~34.0%), DSM (dry soil moisture, 20.3~27.8%), and ESM (extreme dry moisture, 16.6~20.3%) during V8 (8th leaf stage)-VT (tasseling stage). After VT, irrigation was limited. The treated amount of irrigation was 54.1, 47.7, 44.0 and 34.5% of total water requirement, respectively. The potential evapotranspiration during the growing period was $3.29mm\;day^{-1}$, and upward movement of soil water was estimated by the AFKAE 0.5 model in the order of ESM, DSM, OSM, and WSM. We could confirm this phenomenon from actual observations. There was no significant difference in leaf characteristics, dry matter, and primary productivity depending on the level of soil moisture, but leaf development was delayed and dry weight decreased in DSM. However, dry weight and individual productivity of DSM increased after irrigation withdrawal compared to that of OSM. In DSM, ear yield and number of kernels per ear decreased, but water use efficiency and harvest index were higher than other treatments. Therefore, it is considered that the soil moisture is concentratedly managed before the V8 period, the V8-VT period is controlled within the range of 100 to 500 kPa (20.3~27.8%), and no additional irrigation is required after the VT.

• Earthquakes and Structures
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• 제16권5호
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• pp.563-573
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• 2019

When generating spectrum-compatible artificial ground motion in engineering practices, the effect of the variation in fitting parameters on the distribution of the peak ground displacement (PGD) has not yet drawn enough attention. In this study, a method for simulating ground motion matching for multiple targets is developed. In this method, a frequency-dependent amplitude envelope function with statistical parameters is introduced to simulate the nonstationarity of the frequency in earthquake ground motion. Then, several groups of time-history acceleration with different temporal and spectral nonstationarities were generated to analyze the effect of nonstationary parameter variations on the distribution of PGD. The following conclusions are drawn from the results: (1) In the simulation of spectrum-compatible artificial ground motion, if the acceleration time-history is generated with random initial phases, the corresponding PGD distribution is quite discrete and an uncertain number of PGD values lower than the limit value are observed. Nevertheless, the mean values of PGD always meet the requirement in every group. (2) If the nonstationary frequencies of the ground motion are taken into account when fitting the target spectrum, the corresponding PGD values will increase. A correlation analysis shows that the change in the mean and the dispersion values, from before the frequencies are controlled to after, correlates with the modal parameters of the predominant frequencies. (3) Extending the maximum period of the target spectrum will increase the corresponding PGD value and, simultaneously, decrease the PGD dispersion. Finally, in order to control the PGD effectively, the ground motion simulation method suggested in this study was revised to target a specified PGD. This novel method can generate ground motion that satisfies not only the required precision of the target spectrum, peak ground acceleration (PGA), and nonstationarity characteristics of the ground motion but also meets the required limit of the PGD, improving engineering practices.

• The Korean Journal of Pain
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• 제34권2호
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• pp.234-240
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• 2021

Background: Various truncal block techniques with ultrasonography (USG) are becoming widespread to reduce postoperative pain and opioid requirements in video-assisted thoracoscopic surgery (VATS). The primary aim of our study was to determine whether the USG-guided serratus anterior plane block (SAPB) is as effective as the thoracic paravertebral block (TPVB) in VATS. Our secondary aim was to evaluate patient and surgeon satisfaction, block application time, first analgesic time, and length of hospital stay. Methods: Patients in Group SAPB received 0.4 mL/kg bupivacaine with a USG-guided SAPB, and patients in Group TPVB received 0.4 mL/kg bupivacaine with a USG-guided TPVB. We recorded the pain scores, the timing of the first analgesic requirement, the amount of tramadol consumption, and postoperative complications for 24 hours. We also recorded the block application time and length of hospital stay. Results: A total of 62 patients, with 31 in each group (Group SAPB and Group TPVB) completed the study. Between the two groups, there were no significant differences in rest and dynamic pain visual analog scale scores at 0, 1, 6, 12, and 24 hours after surgery. The total consumption of tramadol was significantly lower in the TPVB group (P = 0.026). The block application time was significantly shorter in Group SAPB (P < 0.001). Conclusions: An SAPB that is applied safely and rapidly as a part of multimodal analgesia in patients who undergo VATS is not inferior to the TPVB and can be an alternative to it.

• Journal of the Korean Wood Science and Technology
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• 제32권2호
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• pp.65-72
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• 2004

요소-멜라민수지 접착제를 실험실에서 수지 접착제 고형분량에 대해 5% 멜라민을 첨가하여 파티클보드 제조용으로 합성하였다. 합성한 요소-멜라민 수지를 이용하여 전건 목재파티클의 무게에 대해 접착제 첨가량 6, 8%와 열압시간 3, 4, 5분에서 실험실 파티클보드를 접착하는 열압시간동안 배출되는 가스를 증류수에 용해·포집하여 얻어진 용액으로부터 포름알데히드 배출량을 미국 National Institute of Occupational Safety and Health (NIOSH) 3500의 방법에 의해 분석·비교하였다. 포름알데히드 배출량을 측정하여 분석한 결과는 파티클보드를 열압하는 시간동안 배출되는 가스 중에서 포름알데히드량은 요소-멜라민수지 접착제의 첨가량과 열압시간에 대해 통계적으로 유의하게 차이가 있다는 것을 보여줬다. 파티클보드의 성능평가 결과는 3분의 열압시간에서 접착된 파티클보드의 박리강도는 KS F 3104 파티클보드 8.0형의 최소요구치를 만족시키는 것을 보여줬다.

• 전기전자학회논문지
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• 제26권1호
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• pp.1-9
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• 2022

전력시스템의 신뢰성을 보장하며 분산전원의 수용성을 높이기 위해 IEEE 1547과 같은 표준을 개정하여 분산전원의 계통 연계기준을 강화하고 있다. 본 논문은 이러한 표준을 준수하는 IEEE 1547-2018 기반의 스마트 인버터 기능의 제어 알고리즘을 제안하고, 스마트 인버터 기술의 검증을 위해 구축한 Power HILS 기반의 테스트 플랫폼을 소개한다. 스마트 인버터 기능 중 Volt-var 제어와 Frequency-watt 제어 알고리즘은 상호운용성 표준을 준수하도록 해당 기능의 curve를 상위로부터 설정할 수 있도록 하며, 각 기능의 Enable 신호 시점을 상위 지령에 따라 제어할 수 있도록 하였다. 표준에 따라 Power HILS 테스트 플랫폼을 통해 Volt-var 제어와 Frequency-watt 제어에 대한 형식시험을 수행하였고, 명시된 표준 형식시험을 전부 만족함을 측정 결과를 통해 검증하였다.

• Korean Chemical Engineering Research
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• 제62권2호
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• pp.153-162
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• 2024

발사 전 발사장 주변 해상 위험구역 안전확보는 필수 조건이다. 해상안전이 확보되지 못한 경우 발사는 중지 또는 연기되는 상황에 직면하게 된다. 하지만, 수상 레저 활동 인구 증가 등으로 해상 공공안전 확보에 어려움이 발생하고 있다. 통제해역 내 선박 진입, 수상 레저 장비의 무단출입과 소개 명령 불응이 해당 된다. 본 논문에서는 발사체 개발 및 발사장 운영 전문가 등 22명을 대상으로 델파이/ 계층분석법을 활용하여 해상 공공안전 위협요인을 10개 항목으로 도출하고, 해상안전 확보를 위하여 개선하여야 할 항목 5개를 도출하였다. 본 논문에서 분석한 결과 해상안전 확보를 위하여 가장 개선이 필요한 항목은 발사장 주변 위험구역 설정과 통제에 대한 관계법령 개정이나 단행법 제정 필요성이 있다. 본 논문은 전문가 의견에 대하여 중요도와 우선순위를 분석하고 일관성을 검증하여 객관적인 의견을 제시한 부분에 의미가 있다고 사료 된다.

• 한국간담췌외과학회지
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• 제28권2호
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• pp.115-124
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• 2024

To compare the outcomes of low central venous pressure (CVP) to standard CVP during laparoscopic liver resection. The study design was a systematic review following the PRISMA statement standards. The available literature was searched to identify all studies comparing low CVP with standard CVP in patients undergoing laparoscopic liver resection. The outcomes included intraoperative blood loss (primary outcome), need for blood transfusion, mean arterial pressure, operative time, Pringle time, and total complications. Random-effects modelling was applied for analyses. Type I and type II errors were assessed by trial sequential analysis (TSA). A total of 8 studies including 682 patients were included (low CVP group, 342; standard CVP group, 340). Low CVP reduced intraoperative blood loss during laparoscopic liver resection (mean difference [MD], -193.49 mL; 95% confidence interval [CI], -339.86 to -47.12; p = 0.01). However, low CVP did not have any effect on blood transfusion requirement (odds ratio [OR], 0.54; 95% CI, 0.28-1.03; p = 0.06), mean arterial pressure (MD, -1.55 mm Hg; 95% CI, -3.85-0.75; p = 0.19), Pringle time (MD, -0.99 minutes; 95% CI, -5.82-3.84; p = 0.69), operative time (MD, -16.38 minutes; 95% CI, -36.68-3.39; p = 0.11), or total complications (OR, 1.92; 95% CI, 0.97-3.80; p = 0.06). TSA suggested that the meta-analysis for the primary outcome was not subject to type I or II errors. Low CVP may reduce intraoperative blood loss during laparoscopic liver resection (moderate certainty); however, this may not translate into shorter operative time, shorter Pringle time, or less need for blood transfusion. Randomized controlled trials with larger sample sizes will provide more robust evidence.

• Journal of Microbiology and Biotechnology
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• 제34권5호
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• pp.1154-1163
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• 2024

Glucosylation is a well-known approach to improve the solubility, pharmacological, and biological properties of flavonoids, making flavonoid glucosides a target for large-scale biosynthesis. However, the low yield of products coupled with the requirement of expensive UDP-sugars limits the application of enzymatic systems for large-scale. C. glutamicum is a Gram-positive and generally regarded as safe (GRAS) bacteria frequently employed for the large-scale production of amino acids and biofuels. Due to the versatility of its cell factory system and its non-endotoxin producing properties, it has become an attractive system for the industrial-scale biosynthesis of alternate products. Here, we explored the cell factory of C. glutamicum for efficient glucosylation of flavonoids using apigenin as a model flavonoid, with the heterologous expression of a promiscuous glycosyltransferase, YdhE from Bacillus licheniformis and the endogenous overexpression of C. glutamicum genes galU1 encoding UDP-glucose pyrophosphorylase and pgm encoding phosphoglucomutase involved in the synthesis of UDP-glucose to create a C. glutamicum cell factory system capable of efficiently glucosylation apigenin with a high yield of glucosides production. Consequently, the production of various apigenin glucosides was controlled under different temperatures yielding almost 4.2 mM of APG1(apigenin-4'-O-β-glucoside) at 25℃, and 0.6 mM of APG2 (apigenin-7-O-β-glucoside), 1.7 mM of APG3 (apigenin-4',7-O-β-diglucoside) and 2.1 mM of APG4 (apigenin- 4',5-O-β-diglucoside) after 40 h of incubation with the supplementation of 5 mM of apigenin and 37℃. The cost-effective developed system could be used to modify a wide range of plant secondary metabolites with increased pharmacokinetic activities on a large scale without the use of expensive UDP-sugars.

• 한국간담췌외과학회지
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• 제26권3호
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• pp.270-276
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• 2022

Backgrounds/Aims: Thoracic epidural analgesia (TEA) is an established analgesic method in open Kausch-Whipple pancreaticoduodenectomy (KWPD). Although, it can cause hemodynamic instability and neurological complications. Inter pleural analgesia (IPA) is an alternative option. We aim to evaluate the effectiveness of IPA versus TEA after KWPD. Methods: We retrospectively studied the efficacy of IPA against TEA in patients, operated by a single surgeon. The primary outcome was the analgesic efficacy and secondary outcomes were analgesia-related complications, inotrope use, and duration. Results: Forty patients (TEA, 22; IPA, 18) were included. Both groups were well matched for patient characteristics, type, and duration of surgery. TEA was associated with higher analgesia-related complications (n = 8, 36.4% vs. n = 1, 5.6%; p = 0.027). TEA complications included analgesia not working (n = 4), leakage (n = 2), refractory hemodynamic instability (n = 1), and lower limb anaesthesia (n = 1). One patient in the IPA group encountered leakage. TEA was associated with longer inotrope requirement (35 vs. 18 hours; p = 0.047). There was no significant difference in intensive care unit (ITU) admission rate (81.8% vs. 77.8%; p > 0.999), median ITU stay (3 vs. 2 days, p = 0.385), or hospital stay (11 days in both groups). Conclusions: In open KWPD, IPA is not inferior to TEA in its efficacy of pain control. IPA was associated with less analgesia-related complications and shorter inotrope requirements. However, this was a small retrospective study. Larger randomized controlled trials are needed to study the effectiveness of IPA.

• The Korean Journal of Pain
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• 제37권4호
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• pp.343-353
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• 2024

Background: This study aimed to compare the intercostal nerve block (ICNB) and thoracic paravertebral block (TPVB) for acute herpes zoster-associated pain (ZAP) and possible prophylaxis for post-herpetic neuralgia (PHN). Methods: This study enrolled 128 patients with ZAP. Their records were stratified into standard antiviral treatment (AVT) plus US-guided TPVB (the TPVB group), AVT plus US-guided ICNB (the ICNB group) or AVT alone (the control group). Herpes zoster (HZ)-related burden of illness (HZ-BOI) within the post-procedural 30 days was defined as the primary endpoint, determined by a composite of pain severity and follow-up duration. Procedure time, rescue analgesic requirement, PHN incidence, health-related quality of life and side effects were also recorded. Results: Significantly lower HZ-BOI-AUC₃₀ was reported in the TPVB and ICNB groups as compared to the control group, with a mean difference of 57.5 (P < 0.001) and 40.3 (P = 0.003), respectively. However, there was no difference between the TPVB and ICNB groups (P = 0.978). Both TPVB and ICNB reported significantly greater improvements in PHN incidence, EQ-5D-3L scores and rescue analgesic requirements during follow-up, as opposed to the control AVT. Shorter procedure time was observed in ICNB as compared to TPVB (16.47 ± 3.39 vs. 11.69 ± 2.58, P < 0.001). Conclusions: Both US-guided TPVBs and ICNBs were effective for ZAP, and accounted for possible prophylaxis for PHN, as compared to AVT alone. The ICNB approach could be recommended as an alternative to conventional TPVB with a better consumed procedure time and side effect profile.