본 연구는 그린커피빈추출물이 「건강기능식품의 기준 및 규격」에 추가로 등재될 경우를 대비하여 표준화된 클 로로겐산 시험법을 설정하고, 카페인이 동시 분석되도록 최적화하는 연구를 진행하였다. 최적화된 시험법을 마련 하기 위해 기기분석 및 전처리 조건을 비교·분석하여 클 로로겐산과 카페인을 30% 메탄올 추출하여 인산용액과 인산 함유 아세토니트릴으로 액체크로마토그래프를 통해 330 nm, 280 nm에서 분석하도록 시험법을 설정하였다. 시 험법 밸리데이션 결과, 직선성 정량범위 내에서 상관계수 (R2) 0.999 이상의 유의수준을 보였고, 클로로겐산과 카페 인 검출한계는 0.5와 0.2 μg/mL, 정량한계는 1.4와 0.4 μg/ mL로 나타났다. 정밀도와 정확도 결과는 AOAC 밸리데 이션 가이드라인를 통해 적합함을 확인하였고, 클로로겐 산 및 카페인 동시분석법을 최종적으로 마련하였다. 또한, 시제품과 유통제품을 통해 제형별 적용성 검토하여 클 로로겐산과 카페인을 동시에 정량 가능한 시험법임을 재확인하였다. 최적화된 시험법은 클로로겐산을 함유한 건강기능식품 품질관리에 대한 신뢰성을 더 높일 것으 로 본다.

Injection molding is a process of shaping resin materials by heating them to a temperature above their melting point and then using a mold. The resin material is injected into and cooled within the mold cavity, solidifying into the desired shape. The core and cavity components that make up the mold cavity are crucial elements for the precision molding in injection molding. In the case of precision mold production, the application of 5-axis machining technology is required to ensure high machining quality for complex shapes, and among these factors, the tool angle is a critical machining condition that determines the surface roughness of the workpiece. In this study, we aim to measure the surface roughness of the machined surface of KP4A specimens during machining processes with variations in the tool angle and analyze the correlation between the tool angle and surface roughness.

본 논문에서는 역전파 방법 기반 자동미분법을 이용하여 설계민감도를 구하고 이를 응력제한조건을 고려한 위상최적설계에 적용 하였다. 응력제한조건이 있는 위상최적화문제는 특이점(singularity)과 응력의 국부성(local nature of stress constraint)문제, 그리고 설 계 변수에 대한 비선형성의 문제를 포함하고 최적해를 얻기가 매우 힘들다. 특이점 문제를 해결하기 위해서 응력 완화(stress relaxation) 기법을 사용하였고, 응력의 국부성을 해결하기 위해 p-norm을 이용한 전역 응력치를 제한조건에 사용하였다. 설계 변수에 대한 비선 형성을 극복하기 위해 해석적인 방법으로 정확한 설계민감도를 구하는 것이 중요하다. 위상최적설계에서 기존에는 보조변수방법 (adjoint variable method)을 사용하여 빠르고 정확한 설계민감도를 구했지만, 설계민감도를 해석적으로 구해야 하고, 보조평형방정식 을 추가로 풀어야 하는 어려움이 있다. 이를 해결하기 위해서 인공신경망에서 최적 가중치(weights)와 편차(biases)를 구할 때 쓰이는 역전파 기법을 이용하여 설계민감도를 구하고 이를 응력제한조건을 고려한 위상최적설계에 적용하였다. 역전파 기법은 자동미분에 쓰이는 기법으로 목적함수나 제한조건에 대한 설계민감도를 별도의 수식유도 없이 간단하게 구할 수 있는 장점이 있다. 또한, 미분값 을 구하는 역전파의 과정이 보조평형방정식을 푸는 것보다 계산시간이 빠르고 해석적 방법으로 구한 설계민감도와 같은 정확도를 보 여준다

본 논문에서는 3차원 엮임 재료의 유체투과율 향상을 목적으로 수치해석 데이터 기반의 물성치 회귀 분석 및 최적설계를 소개한다. 우선 3차원 엮임 재료를 구성하는 와이어 사이의 간격을 결정하는 배율 계수를 매개변수화 하여 다양한 배율 조합을 가지는 수치 모 델을 생성하였고, 전산 수치해석을 통해 계산된 각 모델의 체적 탄성계수, 열전도 계수, 유체투과율 데이터를 이용하여 다항식 기반의 회귀 분석을 수행하였다. 이를 사용해서 체적 탄성계수와 유체투과율 사이의 다목적함수 최적설계를 통한 파레토 최적해를 도출하였 으며, 두 물성치가 서로 상충 관계에 있음을 확인하였다. 한편 3차원 엮임 재료의 열전달 효율을 높이기 위해서 유체투과율을 최대화 시키는 것을 목적으로 경사도 기반 최적설계를 수행하였고, 제약조건인 체적 탄성계수의 크기별 유체투과율의 변화율을 분석하였다. 그 결과 설계자가 원하는 최소한의 강성을 가지는 최대 유체투과율 설계 모델을 얻어낼 수 있음을 확인하였으며, 회귀 방정식을 통해 서 얻어진 설계가 높은 정확도를 가지고 있음을 추가적으로 검증하였다.

This study aims to establish a modified analytical method with sensitivity and reliability for streptomycin (STP) and dihydrostreptomycin (DHS) of residues level in pig tissues, plasma and urine by LC-MS/MS on the basis of previous studies. The mass parameters of quantitative and qualitative ions for STP and DHS were optimized using multiple reaction monitoring in positive mode. The separation of compounds was conducted using BEH Amide column according to material’s characteristics. The analytes in plasma were extracted with only organic solvents. In muscle and kidney, KH2PO4 buffer solution containing 2% CCl3COOH and EDTA-Na was used as extraction solvent. The WCX cartridege was selected as SPE cartridge in considering high recoveries for STP and DHS. The analytes in urine were extracted by organic solvents with acid and addition of EDTA. The limits of detection (LODs) in STP and DHS ranged 0.45~3.66 μg/kg and 0.22~0.78 μg/kg, respectively. The limits of quantification (LOQs) were 1.35~11.10 μg/kg in STP and 0.66~2.36 μg/kg in DHS. The recoveries (%) were 94.29~104.5% in STP and 92.32~108.45% in DHS except for plasma with lower values (61.45/68.5%, respectively). In the precision evaluation, the coefficient of variation (CV, %) of STP showed <10.50% on intra-day and <18.04% on inter-day. The CV (%) of DHS showed <8.42% on intra-day, whereas <17.98% on inter-day. The modified method is reliable for continuous residual monitoring in pig to ensure food safety for consumer’s health. In addition, this method could be used in study relation to residue depletion and pharmacokinetics of veterinary drug.

The sub-frame is located on the lower body of a monocoque type vehicle and serves as an engine and suspension, and is an important object part that receives a lot of load. The existing press-type sub-frame has a large number of parts for assembling, which causes an increase in cost. Changing the machining form of this part from the existing press-type machining method to the hydro-forming machining method has the advantage of reducing the cost and weight at the same time due to the reduction of the process. Therefore, in this study, the purpose of this study is to change the design so that the sub-frame of the existing press type can be changed to the hydro-forming process method. To this end, we intend to present a design method by analyzing the effect on the rigidity of the sub-frame using the existing machining method through shape optimization analysis.

In this present investigation, machinability studies on novel aluminum composite with hybrid reinforcements of copper-coated 4% carbon fibers (CFs) and 3% nanoclay in AA6026 matrix fabricated by compocasting method is performed. Step drill bit and multifaceted drill bit are used by adopting central composite design (CCD) in response surface methodology (RSM). The outcomes show that, with a rise in rotational speed surface irregularities, resultant force and material removal rate (MRR) intensifies, and with the additional rise in rotational speed, all the outputs decrease considerably. High MRR, resultant cutting force, and surface roughness are obtained with multifaceted carbide drills, compared with a step drill. Desirability function is used to maximize the MRR and minimize the resultant cutting forces considering the constant surface roughness of 3 μm. The optimal values are rotational speed of 1285 rpm, feed rate of 60 mm/min with the step drill bit, producing an MRR of 0.0439 kg/sec and a resultant cutting force of 185.818 N. The second-order empirical models are developed for outputs, which are fed into the non-traditional metaheuristic Evaporation Rate-based Water Cycle Algorithm (ER-WCA) therefore the lower objective value is achieved with step drill of 51.7421. It is found that using a step drill the machinability performance of this hybrid nanocomposite is well improved than the machining with other drill bits. This composite fulfills the norms of 2000/53/CE-ELV European environmental directives.

In this study, stiffness evaluation was conducted on the main member, front cross member, and rear cross member, which are three components of sub-frame for SUVs (sports utility vehicles), through mode analysis. As for the design variables used in the analysis, the maximum frequency was examined by varying the width and height of each of the three parts into four types. Of course, the weight at this time is minimized, and the mode is set as a constraint that only bending occurs and no distortion occurs. As a result of the analysis, the member affecting the 1st mode was the rear cross member, and the member having the greatest influence on the 2nd mode was the front cross member. In addition, the member with the greatest influence on the 3rd mode appeared as the rear cross member, indicating that this part had the greatest effect on the bending stiffness.

The multi-layered heat source model is a model that can cover most of existing studies and can be defined with a simple formula. Based on the methodology performed in previous studies, the welding heat source was found through experiments and FEM under the welding power conditions of three cases and the parameters of the welding heat source were analyzed according to the welding power. In this study, parameters of fiber laser welding heat source according to welding power were searched through optimization algorithm and finite element analysis, and the correlation was analyzed. It was confirmed that the concentration of the welding heat source in the 1st layer was high regardless of the welding power, and it was confirmed that the concentration of the welding heat source in the 5th layer (last layer) increased as the welding power increased. This reflects the shape of the weld bead that appears during actual fiber laser welding, and it was confirmed that this study represents the actual phenomenon.

The estimation of heat source model is very important for heat transfer analysis with finite element method. Part I of this study used adaptive simulated annealing which is one of the global optimization algorithm for anticipating the parameters of the Goldak model. Although the analysis with 3D model which depicted the real situation produced the correct answer, that took too much time with moving heat source model based on Fortran and Abaqus. This research suggests the procedure which can reduce time with maintaining quality of analysis. The lead time with 2D model is reduced by 90% comparing that of 3D model, the temperature distribution is similar to each other. That is based on the saturation of heat transfer among the direction of heat source movement. Adaptive simulated annealing with 2D model can be used to estimate more proper heat source model and which could enhance to reduce the resources and time for experiments.

Hairy root culture of ginseng is industrially prospected because the cultivation period of ginseng is relatively long. In this study, the effect of medium concentration and sucrose concentration on hairy root culture of ginseng was evaluated. The optimization of ginseng hairy roots transformed by Agrobacterium rhizogene were performed liquid medium. The MS(Murashinge & Skoog basal medium) concentration was selected with 1/2 strength MS and the optimal sucrose concentration was determined at 2-3%(w/v). At the optimum culture condition, The yield (the ratio of weight of grown hairy root cultures to weight of fresh ginseng hairy roots) and production rate of ginseng root were 19.42 times and 5.73 g/l-day. The major ginsenosides were Rb group, Re and Rg1. The produced total ginsenoside content in the solid medium was 9.87 (mg/g) and increased 1.34 times in the liquid medium (13.23 mg/g). In solid culture, the contents of ginsenosides Rb, Re and Rg1 were 2.14, 3.65 and 1.87 mg/g, respectively. In liquid culture, the contents of ginsenosides Rb, Re and Rg1 were 3.54, 4.12 and 2.63 mg/g, respectively.

본 연구는 3개의 운전변수(압력, 공기량, 운전시간)를 실험 설계하고 마이크로 버블의 종말부상 속도(Terminal rise velocity)를 반응 값으로 하여 예측식 모델과 최적 조건을 수립하였다. 다항식 회귀분석을 통해 펌프의 압력(X1) 4.5bar, 공기량(X2) 3.3L/min 그리고 운전시간(X3)이 2.2min에서 종말상승속도(Terminal rise velocity)에 대한 최적값인 5.14 cm/min (85.7㎛/sec)을 얻었다. 또한, 레이저 입자계수 측정장치를 이용하여 2~5㎛ 및 25~50㎛ 영역에서의 가장 높은 마이크로버블 직경크기 분포를 확인하였다.

깨다시 꽃게(Ovalipes punctatus)는 갑각류로서 우리나라에서 잡히는 매끈 꽃겟속, 주름 꽃 겟속, 톱날 꽃겟속, 민 꽃겟속, 두갈래 민꽃겟속 들 중에 하나이다. 대부분의 꽃게는 가공되지 않은 상태로 찜 또는 찜육 등 반 가공 형태로 산업화 되었지만 최근에 게로부터 생리활성을 나타내는 펩타이드를 생산하는 연구가 발표되고 있다. 본 연구는 항산화 기능성을 나타내는 펩타이드를 선별하고 생산 최저공정 확립에 연구를 수행 하였다. 사용된 효소 alcalase, bromelain, flavourzyme, neutrase, papain, protamex들 중에서 bromelain으로 생산된 꽃게육 단백질 가수분해물이 가장 높은 활성을 보여 주었다. 꽃게육 단백질의 bromelain 가수분해물의 펩타이드들의 분자량 분포는 500-3,200 Da로서 7 종류의 이상의 펩타이드들로 구성되었다. 가수분해물의 구성아미노산 분포는 항산화 기능성에 관련된 소수성 아미노산은 전체 42.54%를 차지하였다. 가수분해물의 최적 생산 수율 조건을 확립하기 위하여 공정 조건, 효소 반응 온도 40-60℃, pH 6-8, 효소의 농도 1–3%(w/v)로 표면반응 분석법을 수행한 결과 효소 반응온도 55℃, 반응 pH 6.5, 효소의 양은 3%(w/v)에서 결정되었다. 최적 조건에서 단백질 가수분해도는 최대 71.60%에 도달하였다.

기존의 한방향 펌프는 순환과 배수를 위해 각각의 모터를 사용하지만, 양방향 펌프는 하나의 모터로 모터의 회전 방향에 따라 배수와 순환이 모두 가능하므로 원가절감이 가능하다. 하지만 양방향 펌프는 배수와 순환 시 펌프 케이싱 내부에서 역류와 흡입이 발생하여 유입된 물이 각각 배출구와 순환구로 원활하게 유출되지 못하는 단점이 있다. 본 연구에서는 주효과 분석을 통해 배출과 순환 시 유출되는 유량과 토크에 주요한 영향을 미치는 인자를 설계변수로 선택하여 실험계획법, 근사 모델, 그리고 최적설계를 통해 펌프 케이싱 형상을 최적화함으로써 역류와 흡입은 개선하고 펌프의 토크 대비 배출구와 순환구의 유량을 증가시키는 효과를 거두었다.

Recently, interest in the development of alternative water resources has been increasing rapidly due to environmental pollution and depletion of water resources. In particular, seawater desalination has been attracting the most attention as alternative water resources. As seawater desalination consumes a large amount of energy due to high operating pressure, many researches have been conducted to improve energy efficiency such as energy recovery device (ERD). Consequently, this study aims to compare the energy efficiency of RO process according to ERD of isobaric type which is applied in scientific control pilot plant process of each 100 m3/day scale based on actual RO product water. As a result, it was confirmed that efficiency, mixing rate, and permeate conductivity were different depending on the size of the apparatus even though the same principle of the ERD was applied. It is believed that this is caused by the difference in cross-sectional area of the contacted portion for pressure transfer inside the ERD. Therefore, further study is needed to confirm the optimum conditions what is applicable to the actual process considering the correlation with other factors as well as the factors obtained from the previous experiments.