• 한국전기전자재료학회논문지
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• 제30권4호
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• pp.246-252
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• 2017

Pulverized $FeS_2$ (pyrite) gives different discharge test results with as-received $FeS_2$ electrodes. The as-received $FeS_2$ electrode shows three voltage plateaus during the discharge test. However, the ball-milled $FeS_2$ electrode shows two voltage plateaus. To interpret this result, the effect of $FeS_2$ particle size on electrochemical reactions is investigated by unit cell discharge tests, SEM and XRD. As a result, it is found that the transition reaction product ($Li_2+xFe+xS_2$) of $FeS_2$ explains the difference. The as-received $FeS_2$ reacts according to three reaction steps ($FeS_2{\rightarrow}Li_3Fe_2S_4{\rightarrow}Li_2+xFe_1+xS_2{\rightarrow}LiFe_2S_4$). However, ball-milled $FeS_2$ reacts without the $Li_2+xFe_1+xS_2$ stage. In this study, this result is explained by the difference in electrochemical reaction mechanism. The as-received $FeS_2$ has a larger radius than the ball-milled $FeS_2$. Therefore, the lithium ion has to diffuse into the $FeS_2$ unreacted core, and $Li_2+xFe_1+xS_2$, the transition reaction product of as-received $FeS_2$, is formed during this stage.

• 유통과학연구
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• 제14권4호
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• pp.127-134
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• 2016

Purpose - Value chain in agriculture refers to direct and indirect activities related to value-added process from raw materials to final products in agricultural industries. In recent years, value chain analysis has become more important in the area of agricultural development. This article reviews the concept and importance of value chain analysis in the context of agricultural development and attempts to suggest improvement strategies. Research design, data, methodology - A literature survey was conducted for value chain analysis for agricultural development. The case of agro-value chain in Cambodia was deeply analyzed based upon interviews with government officers and related experts. Results - It seems that agro-value chain in developing countries are not well developed and does not carry out appropriate functions, compared to developed countries. Because value adding facilities, such as storage, processing and packing plants, milling plants, and etc. are not sufficiently constructed, the quality of agricultural products is low. Especially developing countries may loose opportunities to increase value of their product by exporting their agricultural products as raw materials to neighboring countries. Value adding process is also mainly controlled by traders in local markets or wholesale markets in urban areas. Farmers therefore can get lower share of final value of agricultural products compared to the shares paid to traders. Lastly it is argued that governments of developing countries do not play an active role in developing value chains and do not carry out coordinating functions in an effective and efficient manner. Conclusions - The first step to improve agro-value chain in developing countries is to identify and analyze value chain structure of agricultural products and to make development strategies and implementation programs. For improving value chain of agricultural products in developing countries, it is required to provide not only plans for constructing hardwares, such as wholesale markets, storage facilities, processing and packing plants, and etc., but also plans for improving softwares, such as measures for improving product quality and safety, setting up grade and standard, providing market information, and nurturing producer cooperatives.

• 한국작물학회지
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• 제59권4호
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• pp.463-469
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• 2014

유색 수수인 황금찰수수를 도정할 때 grain과 함께 발생하는 도정부산물인 hull과 bran의 4가지 용매 추출물의 총 폴리페놀 함량, 항산화 활성, 천연색소 함량과 RAW 264.7 세포주를 이용하여 항염증 활성을 검정하였으며 결과를 요약하면 아래와 같다. 1. 도정부산물인 hull의 100% 메탄올과 70% 에탄올 추출물에서 총 폴리페놀 함량이 $29.4{\pm}0.4$와 $29.7{\pm}0.2mg\;GAE/100g$으로 가장 많았고, ABTS 라디컬 소거능($IC_{50}$)이 $6.8{\pm}0.4$, $6.3{\pm}0.1{\mu}g/mL$로 가장 높은 항산화 활성을 나타내었다. 2. 총 천연색소 함량에서도 수수 hull의 0.5% 염산 함유 100% 메탄올 추출물에서 $322.6{\pm}14.5mg/100g$으로 가장 많은 색소 함량을 나타내었고 hull, bran, grain 모두의 경우에서 0.5% 염산을 함유한 100% 메탄올을 용매로 추출한 경우에서 가장 많아 수수를 이용하여 천연색소를 추출할 경우 수수 부산물인 hull을 산을 함유한 메탄올로 추출하였을 때 가장 많은 색소 추출물을 얻을 수 있었다. 3. 수수 도정부산물과 grain 추출물을 LPS로 NO 생성을 유도한 RAW 264.7 세포에 처리하였을 때, 세포 독성이 없는 100 ug/mL 농도 이하에서의 NO 생성 억제량은 hull, bran, grain 추출물의 순으로 나타났고 hull 추출물의 경우에 농도에 따라 가장 큰 NO 생성 억제를 보였으며 천연색소 화합물 중에서는 apigeninidin의 NO 생성 억제 활성을 확인하였다. 4. 위 결과를 종합해 볼 때, 수수 도정부산물 중 hull은 grain에 비해 총 폴리페놀 화합물과 천연색소 함량이 높고 항산화 활성과 RAW 264.7 대식세포에서의 NO 생성량 억제 활성이 우수하여 앞으로 수수 부산물이 항산화 및 항염증 소재로 가능성이 있음을 확인하였다.

• 대한금속재료학회지
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• 제49권2호
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• pp.174-179
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• 2011

We investigated the surface morphology changes of a lithium/sulfur battery using multi-walled canbon nanotube added sulfur electrode during charge-discharge cycling. The Li/S cell showed the first discharge capacity of 1286 mAh/g-S, which utilized is 71% of the theoretical value. It decreased to 328 mAh/g-S at the 100th cycle, which corresponds to about 19% utilization of the total sulfur in the cathode. The spherical lumps of the reaction product were observed on the surface of the sulfur electrode. This material was verified as lithium sulfide by X-ray diffraction measurement. The pores in the separator were filled with reaction product. Thus the diffusion of the $Li^+$ ion decreased, which resulted in the decreased capacity of the Li/S cell.

• Progress in Superconductivity
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• 제1권2호
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• pp.146-150
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• 2000

Step edge Josephson junctions in c-axis oriented $YBa_2Cu_3O_7$ films were fabricated on $CeO_2$ buffered sapphire substrates. The step angle was controlled in the wide range of $20^{\circ}\sim75^{\circ}$ by the Ar ion milling technique. I-V curves of junction fabricated on the thickness ratio of $\sim$0.8 and the step angle of $35^{\circ}$ were exhibited RSJ-like behavior with $I_CR_N$ product of $\sim250{\mu}A$ and critical current density of $\sim2\times10^4A/cm^2$ at 77 K. Critical current of step edge junction was increased linearly with decreasing temperature but the normal resistance was almost constant. Total samples of step edge Josephson junction was satisfied a scaling behavior of $I_CR_N{\propto}(J_C)^{0.5}$.

• 산업공학
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• 제16권1호
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• pp.8-15
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• 2003

With rapid growth of internet technology, companies have developed an information system such as the electronic catalog for product data in the E-Business. Due to the heuristic nature of the catalog search for proper tools in the specific process, the intelligent and user friendly methods residing in the search process give a comfortable environment even for the beginners in the field. In this paper, we develop a web based catalog for machining tools especially in Milling process. It has two distinct procedures for the users of the catalog; Search and Analysis. The Search is to select a proper cutter, insert, component combination in the developed relational database based on the cutting process and material. The Analysis is to suggest a recommended optimal cutting conditions based on the machining tools and selected materials. All of these procedures are stored in a server with a program based on the ASP and Java Script where the procedure is initiated by the client using the internet which is accessed through insert. With the success on implementing the above engineering database in the internet, we can provide the foundation for developing PDM with heuristic procedure.

• 한국식품영양학회지
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• 제35권1호
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• pp.16-33
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• 2022

The quality characteristics and antioxidant activity of Tteokbokkidduk alone or supplemented with 3%, 6%, 9%, and 12% wheat bran powder were assessed, to increase use of the wheat bran by-product of wheat milling. The moisture content, pH, and starch elution of Tteokbokkidduk increased with increasing wheat bran powder, while the water absorption rate did not. The L color value decreased and the a and b values increased with increasing wheat bran powder. Scanning electron microscopy of Tteokbokkidduk prepared with 0% and 3% wheat bran powder revealed uniform pore size distribution. In terms of texture profile analysis, hardness and chewiness increased, while cohesiveness decreased with increased content of wheat bran powder. Acceptance was highest for samples with 6% wheat bran powder. Quantitative description analysis (QDA) revealed increased brownness, roughness, nutty, bitterness, astringency, savory character, and hardness, and decreased adhesiveness, springiness, and chewiness with increased wheat bran powder. Principal component analysis (PCA) revealed highest overall acceptance of samples prepared with 6% wheat bran powder, reflecting the relatively low values of detrimental sensory characteristics. Antioxidant activities of Tteokbokkidduk increased as wheat bran powder content increased. The addition of 6% wheat bran powder resulted in excellent Tteokbokki in terms of acceptance, quality, and antioxidant activity.

• 생약학회지
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• 제44권3호
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• pp.257-262
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• 2013

Osteoporosis is a disease of bones that leads to an increased risk of fracture. In osteoporosis, the bone mineral density is reduced, bone microarchitecture deteriorates, and the amount and variety of proteins in bone are altered. $It^{\circ}{\emptyset}s$ caused by the imbalance between born resorption and born formation. Recently natural products from plants have been extensively studied as therapeutic drugs to treat and prevent various diseases. Wheat bran is the hard outer layers of wheat grain and produced as a by-product of milling in the production of refined grains. In oriental medicines, Bu So Maek (Tritici Immaturi Semen) with wheat bran has been used as bronchitis, sedatives and anti-sweating effects. However effects of wheat bran butanol fraction (WBB, 50 ${\mu}g/ml$) in osteoclast differentiation remains unknown yet. Thus we investigated the effects of WBB on RANKL induced osteoclast differentiation. WBB inhibited osteoclast differentiation by downregulating the RANKL-induced activations of MAP kinases. Moreover mRNA expression of osteoclast-mediating molecules such as c-Fos, NFATc1 and DC-STAMP were attenuated by WBB during osteoclast differentiation. The finding of this study show that WBB and its components might prevent osteoclast-related bone loss.

• 한국정밀공학회지
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• 제18권7호
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• pp.98-105
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• 2001

The machining accuracy is affected by geometric, volumetric errors of the machine tools. To improve the product quality, we need to enhance the machining accuracy of the machine tools. To this point of view, measurement and inspection of finished part as error analysis of machine tools ahas been studied for last several decades. This paper suggests the enhancement method of machining accuracy for precision machining of high quality metal reflection mirror or optics lens, etc. In this paper, we study 1) the compensation of linear pitch error with NC controller compensation function using laser interferometer measurement, 2) the method for enhancing the accuracy of NC milling machining by modeling and compensation of volumetric error, 3) the spherical surface manufacturing by modeling and compensation of volumetric error of the machine tool, 4) the system development of OMM without detaching work piece from a bed of machine tool after working, 5) the generation of the finished part profile by OMM. Furthermore, the output of OMM is compared with that of CMM, and verified the feasibility of the measurement system.

• 대한치과기공학회지
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• 제42권4호
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• pp.321-325
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• 2020

Purpose: This study is to evaluate the accuracy of gypsum replica models made from various gypsum products. Methods: One main model was made of stainless steel by CNC milling process. Molds were formed from the main model, and the gypsum replica models were made using 8 types of type IV gypsum, 10 pieces each. The main model was digitized by a contact scanner (Incise; Renishaw) and the gypsum replicas were digitized by an optical scanner (E4; 3Shape A/S). The difference between the main model and the gypsum replicas were measured by inspection software (3D Systems). One-way ANOVA was performed to evaluate the statistical significance of differences between groups. In addition, the independent sample T test was performed to determine the difference between the conventional and scannable stone group (n=10, α=0.05). Results: The root mean square of the stone models were 7.24 ㎛ to 10.78 ㎛, and statistical significance was found between the two groups (SR, FR) and the other 6 groups (IS, SG, CA, CS, ER, EBG) (p<0.05). The accuracy of the gypsum replicas was 9.04 ㎛ and 7.62 ㎛ in the conventional and scannable stone group, respectively. There was statistical significance between the two groups (p<0.01). Conclusion: In the limited results of this study, the product with low setting expansion and the scannable showed high accuracy. Therefore, in order to obtain a stable and accurate scan model, it is more effective in terms of accuracy to use a scannable stone with a low setting expansion.