• Journal of Magnetics
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• 제8권1호
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• pp.18-23
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• 2003

In our previous work, microstructure and magnetic properties of two-phase exchange-coupled $Sm_2Fe_{15}Ga_2C_{x}$/$\alpha$-Fe nanocomposites have been investigated by means of x-ray diffraction, transmission electron microscopy and magnetization measurement. It was found the exchange coupling between the magnetically hard phase $Sm_2Fe_{15}Ga_2C_{x}$ and the magnetically soft one ${\alpha}$-Fe results in an enhancement of the remanence. The sizes of crystallites of both phases are, however much larger than the Block domain-wall width of the magnetically hard phase. This microstructure gives rise to a concave demagnetization curve and consequently reduces the maximum energy Product. In order to improve their magnetic properties, a few Percent of Zr, which may be effective to refine the microstructure through rapid quenching, was introduced into the nanocomposites. The addition of Zr was found to improve the magnetic properties significantly, Under optimum heat-treatment conditions, the remanence, coercivity and maximum energy Product increase from 0.65 T, 0.48 T and 50 kJ/$m^{3}$ for the Zr-free sample to 0.72 T, 0.77 T and 71.6 kJ/$m^{3}$ for the 1 at.% Zr-containing one, respectively, The improvements of magnetic properties are due to the refinement of microstructure by the addition of Zr.

• 소성∙가공
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• 제21권1호
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• pp.67-74
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• 2012

Although high productivity is possible, cold forged helical gears have not been widely used due to difficulty in achieving mechanical properties as well as dimensional accuracy of the product. Confidence in the gear characteristics also is very important in heavy-duty gear applications. Therefore, the properties of forged gears must be compared to the properties of conventional machined gears. The properties might be different due to the different fabrication processes. In this study, machined and forged products both before and after heat-treated have been compared by measuring the residual stress and involute curve of the tooth. Characteristics of hardness and microstructure were also compared. Additionally, tooth fracture strength was compared for the heat-treated products. Moreover, the tooth strength and the fracture pattern were compared between the machined and forged gears. The forged gear showed decreased changes in residual stress and decreased changes in dimensions when compared to the machined gear before and after heat treatment. The forged gear was over 10% better than the machined gear in tooth strength.

• 무역학회지
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• 제42권1호
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• pp.165-188
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• 2017

본 연구는 1981년부터 2014년까지 128개 국가를 대상으로 한국과 투자대상국의 지적재산권이 한국의 해외직접투자에 미치는 영향을 분석하였다. 첫째, 한국의 지적재산권과 이의 종류인 특허권과 상표권, 의장권 모두 해외직접투자에 긍정적 영향을 미쳤다. 둘째, 투자대상국의 지적재산권은 특허권을 제외하고 해외직접투자에 긍정적 영향을 미쳤다. 셋째, 지적재산권을 투자대상국에서 활용하기 위한 해외직접투자가 투자대상국의 지식을 습득하기 위한 해외직접투자보다 더 유의하였다. 넷째, 주로 개도국인 고성장 국가에 대해서는 한국의 지적재산권이, 주로 선진국인 저성장 국가에 대해서는 투자대상국의 지적재산권이 더 큰 영향을 미쳤다.

• 한국수산과학회지
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• 제35권2호
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• pp.173-178
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• 2002

어획지에 따른 마른멸치의 품질을 제시하기 위하여 남해산, 동해산 및 서해산 마른멸치의 식품학적 품질특성 (아미노산, 무기질 및 지방산과 같은 구성성분,과산화물값 및 색도와 같은 지질산패도, 휘발성염기질소, 형상 등과 기호도 등)에 대하여 비교, 검토하였다. 남해안산 마른멸치의 수분함량은 $22.9\%$로 동해안산 마른멸치($27.4\%$) 및 서해안산 마른멸치 ($27.8\%$)에 비하여 약간 낮았다. 그러나, 산불용성 회분은 어획지에 관계없이 0.29-$0.34\%$의 범위로 차이가 없었다. 남해안산 마른멸치는 동해안산 및 서해안산에 비하여 구성아미노산 함량 (건물 당), 무기질 함량 (건물 당) 및 지방산 조성의 경우 차이가 없었고, 과산화물값 및 (20:5n-3+22:6n-3)/16:0등은 미미한 정도에서 우수하였으며, 색조 및 형상과 같은 관능 특성 은 확연히 우수하였다. 이상의 화학적 분석 및 관능 평가에 의한 어획지에 따른 마른멸치의 품질은 남해안산이 가장 우수하였고, 다음으로 서해안산 마른멸치 $\ge$ 동해안산 마른멸치의 순이었다.

• 한국포장학회지
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• 제13권1호
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• pp.25-28
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• 2007

Physical damage on fruits and vegetables caused by shock degrades the value of product in the fresh market. In order to design a product/package system to protect the product, the peak acceleration or G force to the product that causes shock damage needs to be determined. Shock cushion packaging is applied to protect goods of all kinds. It can be adapted in their shape to any product to be packed, so that its shock absorbing properties is determined by geometry of the product. The shape of a cushion can be adapted to the expected shock loads. To analyze the response properties of cushion materials for packaging of the pears for optimum packaging design during transportation, shock tests were carried out. Shock acceleration that is happened in pears were appeared very high by $25{\sim}30G$ in the input shock acceleration of 14.1618 G that was measured in transportation road. This means that the pears receive the shock acceleration more than maximum double itself and the damage by this can happen and the shock acceleration increase in case use PE tray cup and PE net in fruits, the use of corrugated fiberboard pad may become one method that it can reduce the damage by the shock in packaging of fruits.

• 한국기계가공학회지
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• 제11권3호
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• pp.138-145
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• 2012

The material used in this study is dielectric and ferrite. Because of the unique characteristics of the material, it is easily exposed to external shocks and pressure, which cause damage to the product. However, after being processed under high-temperature environment repeatedly, the mechanical strength of the product is greatly increased due to the change of the electrical properties. In this paper, dielectric and bonded ferrite material was tested for the material properties. The equipment for this experiment was produced and tested to allow Cylindrical and Three-dimensional geometry of the product for the vacuum deposition. For Cylindrical shape of the product, in order to obtain the equivalent film thickness, the device is constructed in a vacuum chamber which gives arbitrary revolving and rotating capability. The electrical performance of the product is obtained through this process as well. However, as mentioned above, with repeating processes under high temperature and exposure to external environment, the product is easy to be broken. This experiment has enabled us to find out a stable condition to apply the communication of the RF high frequency to each of the core elements, such as Ferrite and Dielectric which is then used for the mechanical strength of the Raw material, hetero-junction material, Hetero-junction Ag Coating material and hetero-junction Ag Coating SiO2 Coating material respectively.

• 산업경영시스템학회지
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• 제20권42호
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• pp.59-66
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• 1997

In the process to design a product, the values of the product will be designed must be considered in respect to the multi-dimensional properties consisted of subjective and objective attributes. As same reason, methods to evaluate the design alternatives in the process must evaluate the overall attributes and relationships among its, also. In this paper, the defectivenesses of evaluation methods in the process of product design are summarized. One of the severe defectivenesses of the methods is the insufficient rationality of calculation procedure. Then, we introduce the developed quantitative evaluation method to accomodate this defectiveness and to be considered a evaluator's feeling or ambiguity when evaluating design alternatives by means of fuzzy theory, and suggest it's application steps on the process of product design to be used easily.

• 한국식품저장유통학회지
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• 제4권3호
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• pp.237-243
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• 1997

Numerous variables affect product cooling rate of pressure cooling system for fruits and vegetables. These include carton vent area, initial and desired final product temperature, flow rate and temperature of the cooling air, product size, shape and thermal properties and product configuration(whether in bulk or packed in shipping cartons). This study was carried out to determine the influence of each of these variables as they affect cooling time. The opening ratio and number of the vent hole were recomended as 4∼10% and 2∼4ea., respectively, for a minimum alt flow resistance and for a uniform air flow pattern. In the cooling experiment for tomatoes and mandarins, optimum air flow rate was 0.04 m3/min.kg in terms of energy saving. The cooling air temperature should be about 2$^{\circ}C$ less than the desired final product temperature for reducing cooling time.

• Journal of Biosystems Engineering
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• 제20권4호
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• pp.343-350
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• 1995

In order to design efficient and effective pressure cooling system for fruits and vegetables, a numerical model for temperature prediction of fruits was developed. This model was extended to study the various factors affecting product cooling time, such as product depth, approach air temperature, entering air velocity and initial product temperature. Also, selection of these factors were examined with respect to the efficiency of the pressure cooling system, the overall precooling cost and the final quality of the product. When designing a pressure cooling system for a particular product, the range of the factors must be selected carefully according to the thermal and physiological properties.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2001년도 춘계학술대회 논문집
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• pp.414-417
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• 2001

In today's engineering world, any product development activity requires the expertise and the interaction of many different engineering. Therefore the various activities in a product development architecture are highly distributed and interdependent. The interdependence may be due to sharing of databases and transfer of information between various activities. This will require an integrated product model. That can support distributed design such that participants from different backgrounds collaborate towards one common goal. This paper presents the architecture of the product modeling system for the integration of CAD and CAE. It then reports on the study of STEP 10303 and UG open API focused on the integration of different technical environments.