• 유통과학연구
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• 제21권7호
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• pp.41-50
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• 2023

Purpose: The purpose of the research is identified factors influencing the competitiveness of the copper industry in Kazakhstan. Research design, data and methodology: A few studies are dedicated to the analysis in developing countries, particularly Kazakhstan. The algorithm was chosen for research provision: statistical and comparative analysis, correlation, and regression analysis. The data of 1999-2021 obtained from the World Bank, Bureau of National Statistics, National Bank of Kazakhstan. Results: The obtained results demonstrate the trends in the development of the industry since 2000. The development of the copper industry is strongly influenced by the distribution and state of the business environment, economic situation, and trends in the global commodity markets. Conclusions: According to econometric modeling, there is a correlation between the profitability of the copper industry, GDP, copper prices, liquidity, and energy resource prices. Trends in global commodity and energy markets have a significant impact on the state of the industry. Further research should be conducted to include an analysis and forecast of internal factors that may affect the development of the industry, such as copper reserves, condition of fixed assets, government programs, etc. It is also important to examine the correlation with the trends in the development of the global green economy and the revival of the Chinese market.

• Bulletin of the Korean Chemical Society
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• 제30권2호
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• pp.429-434
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• 2009

The OH($X^2{\Pi},\;{\nu}$"=0, 1) internal state distributions from the reaction of electronically ground state oxygen atoms with HSi$Cl_3$ were measured using laser-induced fluorescence. The ground-state O$(^3P_J)$ atoms with kinetic energies above the reaction barrier were produced by photolysis of N$O_2$ at 355 nm. The OH product revealed strong vibrational population inversion, P(${\nu}$"=1)/P(${\nu}$"=0) = 4.0 ${\pm}$ 0.6, and rotational distributions in both vibrational states exhibit substantial rotational excitations to the limit of total available energy. However, no preferential populations in either of the two $\Lambda$ doublet states were observed from the micropopulations, which supports a mechanism involving a direct abstraction of hydrogen by the atomic oxygen. It was also found that the collision energy between O and HSi$Cl_3$ is effectively coupled into the excitation of the internal degrees of freedom of the OH product ($$ = 0.62, and $<\;f_{rot}>$ = 0.20). The dynamics appear consistent with expectations for the kinematically constrained reaction which supports the reaction type, heavy + light-heavy $\rightarrow$ heavy-light + heavy (H + LH′ $\rightarrow$ HL + H′). The dynamics of oxygen atom collision with HSi$Cl_3$ are discussed in comparison to those with Si$H_4$.

• Nuclear Engineering and Technology
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• 제50권3호
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• pp.368-378
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• 2018

Understanding of turbulent flow in the reactor coolant pump (RCP) is a premise of the optimal design of the RCP. Flow structures in the RCP, in view of the specially devised spherical casing, are more complicated than those associated with conventional pumps. Hitherto, knowledge of the flow characteristics of the RCP has been far from sufficient. Research into the nonintrusive measurement of the internal flow of the RCP has rarely been reported. In the present study, flow measurement using particle image velocimetry is implemented to reveal flow features of the RCP model. Velocity and vorticity distributions in the diffuser and spherical casing are obtained. The results illuminate the complexity of the flows in the RCP. Near the lower end of the discharge nozzle, three-dimensional swirling flows and flow separation are evident. In the diffuser, the imparity of the velocity profile with respect to different axial cross sections is verified, and the velocity increases gradually from the shroud to the hub. In the casing, velocity distribution is nonuniform over the circumferential direction. Vortices shed consistently from the diffuser blade trailing edge. The experimental results lend sound support for the optimal design of the RCP and provide validation of relevant numerical algorithms.

• 설비공학논문집
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• 제17권4호
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• pp.386-395
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• 2005

With the development of a living standard, the importance of indoor air conditioning system in all kinds of buildings and vehicles has increased. A lot of researches on energy losses in a duct and various kinds of flow pattern in branches or junctions have been carried out over many years, because the primary object of a duct system used in HVAC is to provide equal flow rate in the interior of each room by minimizing pressure drop. In this study, to get equal flow distribution in each branch, a blockage is applied to the rectangular duct system. The flow analysis for flow distribution of a rectangular duct with two branches was performed by CFD. By using SIMPLE algorithm and finite volume method, flow analysis is performed in the case of 3-D, incompressible, turbulent flow. Also, the standard $k-{\varepsilon}$ model and wall function method were used for analysis of turbulent fluid flow. The distribution diagrams of static pressure, velocity vector, turbulent energy and kinetic energy in accordance with variation of Reynolds number and blockages location in a rectangular duct show that flow distribution at duct outlets is improved by a blockage. In this rectangular duct system, mean velocity and flow rate distribution in two branch outlets are nearly constant regardless of variation of Reynolds number, and a flow pattern of the internal duct has a same tendency as well.

• 설비공학논문집
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• 제10권1호
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• pp.1-10
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• 1998

A header is the device that makes uniform flow distribution in all branches from header of heat exchangers, pipe burner or chemical equipments. In this study, experimental tests have been performed in order to investigate the flow distribution characteristics in a straight header and tapered header which have 6 and 11 glass pipe branches. The experimental equipment consists of a water circulation system where the fluid velocity in each glass pipe is measured by Ar-ion LDV system. From the experiments and the theoretical equation, it could be recommended that tapered header should be determined so that its internal velocities inside the header become uniform according to taper of the header and number of attached branches for uniform flow distribution in energy systems.

• 동의생리병리학회지
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• 제16권2호
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• pp.397-402
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• 2002

Clinical studies were done treated with aroma therapy in 22cases of patients for suffering allergic rhinitis. who were treated at Dept of Oriental respiratory internal medicine in the Hospital of Taejeon University from January 2001 to May 2001. The results were as follows. 1. In distribution of sex & age. 45.5% of them were man, and 54.5% of them were woman. Of those who were attached, 2. In distribution of occupation, 59% of them were student, 18% of them were housewife, 18% of them were white color, 9% Of them were blue color. 3. In distribution of the period of the clinical history, under six months was 32%, under 1 year was 9%, under 3 years was 27%, over 3 years was 32%. 4. In distribution of the seasonal contributing factor, most of them were perenial allergic rhinitis, others generally started in spring or winter. 5. In distribution of past history, 59% of them are none, 18% of them are asthma, 18% of them are atopic dermatitis, 5% of them are allergic dermatitis. 6. In distribution of family history, 46% of them are none, 27% of them are sibling line, 18% of them are paternal line, 9% of them are maternal line. 7. In distribution of symptom, the ratio of sneezing was 90%, nasal discharge was 81 %, nasal obstruction was 46%, pruritus was 41 %, headache was 31%, asthma was 22%, digestion disorder was 18%, tears was 9%, nosebreeding was 5%. 8. In distribution of diagnosis in descending order, wind-cold evil was 5%, spleen-lung energy asthnia was 31 %, lung-kidney asthnia was 64%. 9. In distribution of Herb medicine treatment, Tonggyu-tang was the most, the second was hyunggaiyunyo-tang. 10 In emotional change of patients aroma-therapy, only 14% of them felt good. 11. The total remedial value of the 22 patients was revealed 32.9%. 12. In proportion to grow older, the remedial value were decreased. 13. In proportion to the period of the clinical history was longer, the remedial value were decreased.

• 한국에너지공학회:학술대회논문집
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• 한국에너지공학회 2002년도 추계 학술발표회 논문집
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• pp.17-23
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• 2002

The objective of this study is to develop a new oil combustion technology concerning industrial furnaces and kilns, not only to save energy but also to reduce environmental emissions. Of many kinds of such technologies we chose the high temperature air combustion technology which was initiated by the British steel company in '80s and developed further by the American burner company "North American". In this study it was carried out to test regenerative burner experimentally and to have an applicability to industry. From the variation of configuration of gas nozzle and hot test on the temperature distribution and NOx, it was found out that the reduction of NOx was due to the effect of internal gas recirculation, which will be caused by air emitting velocity from burner nozzle.

• 한국수소및신에너지학회논문집
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• 제33권4호
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• pp.363-371
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• 2022

In this study, the operation characteristics of the internal reforming type molten carbonate fuel cell (MCFC) were studied using computational fluid dynamics (CFD) analysis according to the steam to carbon ratio (S/C ratio), operating temperature, and gas utilization. From the simulation results, the distribution of gas composition due to the electrochemical reaction and the reforming reaction was predicted. The internal reforming type showed a lower temperature difference than the external reforming type MCFC. As the operating temperature decreased, less hydrogen was produced and the performance of the fuel cell also decreased. As the gas utilization rate decreased, more gas was injected into the same reaction area, and thus the performance of the fuel cell increased.

• Journal of Advanced Marine Engineering and Technology
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• 제32권8호
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• pp.1201-1207
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• 2008

Numerical analysis information will be very useful to improve fluid system. General information about an internal gas flow is presented by numerical analysis approach. Relating with hydrogen compressing system, which have an important role in hydrogen energy utilization, this should be a useful tool to observe the flow quickly and clearly. Flow characteristic analysis, including pressure and turbulence kinetic energy distribution of hydrogen gas coming to the cylinder of a reciprocating compressor are presented in this paper. Suction-passage model is designed based on real model of hydrogen compressor. Pressure boundary conditions are applied considering the real condition of operating system. The result shows pressure and turbulence kinetic energy are not distributed uniformly along the passage of the Hydrogen system. Path line or particles tracks help to demonstrate flow characteristics inside the passage. The existence of vortices and flow direction can be precisely predicted. Based on this result, the design improvement, such as reducing the varying flow parameters and flow reorientation should be done. Consequently, development of the better hydrogen compressing system will be achieved.

• Journal of Advanced Marine Engineering and Technology
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• 제34권6호
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• pp.792-797
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• 2010

가정용 조리기구인 전자레인지는 구동시 필요한 고주파의 형성을 위하여 고전압 발생장치와 고 전압 축전지 등의 장치가 사용된다. 이 장치들은 높은 전압에서 구동되기 때문에 다량의 열에너지를 방출한다. 따라서 방출된 열에너지는 전자레인지 본체의 온도를 상승시키는 요인이 된다. 본 연구에서는 쿨링팬 구동조건과 열에너지 발생조건에 따른 전자레인지 내부의 온도 분포를 해석하였다. 해석결과 쿨링팬에서 유출되는 공기의 속도가 증가함에 따라 내부 온도가 감소하는 것을 확인하였으며 감소하는 정도를 정량적으로 분석하였다. 그리고 열에너지 방출량을 조정하여 내부 온도분포를 조사하였다.