• Applied Science and Convergence Technology
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• v.24 no.4
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• pp.77-83
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• 2015

Many welding processes are performed to construct cryogenic system. Leak-tight for the cryogenic system is required at low temperature environment. Helium leak detection techniques are commonly used to find leak for the cryogenic system. The helium leak detection techniques for spraying, sniffing and pressurizing techniques are introduced. High vacuum is also necessary to use helium leak detector. So, types of fluid flow, effective temperature, conductance and pumping speed are introduced for vacuum pumping. Leak test procedure is shown for pipe welding, cryomodule and low temperature test. Cryogenic seals which include copper gasket, helicoflex gasket and indium are investigated.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.442-446
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• 2004

Reducing the particle size of drug materials down to submicron is an important matter in pharmaceutical industry. Cryogenic milling technology is one of the mechanical milling processes, which is mostly utilized in refining grain size of metal and ceramics at extremely low temperature environment. This technique has not been readily studied in application to medical and biotechnology. This paper, therefore, describes the application of cryogenic milling process to reduce particle size of Ibuprofen. The shape and size of the Ibuprofen particle before and after the cryogenic ball milling process were analyzed. XRD analysis was performed to examine a change in crystallinity of Ibuprofen by the cryogenic ball milling process. The results showed that the size of Ibuprofen particles was reduced to 1/10 or less of its initial size. The results also showed that the degree of crystallinity of Ibuprofen was slightly reduced after cryogenic ball milling with nitrogen

• Transactions of The Korea Fluid Power Systems Society
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• v.3 no.4
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• pp.8-13
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• 2006

The high pressure cryogenic ball valve is used to transfer the liquefied natural gas which temperature is $-196^{\circ}C$, supplied pressure is $168kgf/cm^2$. In the present work, the temperature distribution and thermal deformation is calculated numerically. The CAR and CFD methods are useful to predict the thermal matter and the inner flow field of high pressure cryogenic ball valve. For this reason, to optimum design of the cryogenic ball valve, the theological behavior of the supplied LNG in a cryogenic valve has been studied. The governing equations are discredited and solved numerically by the finite-volume method and finite-element method. In this study, we designed the high pressure cryogenic ball valve that accomplishes zero leakage by elastic seal at normal temperature and metal seal at high temperature.

• 한국가스학회:학술대회논문집
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• 1998.09a
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• pp.115-119
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• 1998

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2004.03a
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• pp.234-239
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• 2004

In the development of rocket turbo-pump, cavitation at the inducer is one of the major problems. Cryogenic fluids are commonly used for rocket propellant, therefore, thermodynamic effect becomes noticeable compared to conventional water cavitation. In the present study, a numerical simulation method for cryogenic cavitation is proposed, which reveals the difference between cryogenic and water cavitation.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.41 no.6
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• pp.661-672
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• 1992

In this study, the 154kV 800 MVA cryogenic resistive cable and its power transmission system were designed and built in a purpose of suggestion a plan using high density and large power transportation systems in practice to solve the recent increase in demands of electrical energy. Cryogenic resistive cable uses the benefits of increasing the conductivity of matals in LNS12T. We describe the details of designs of cryogenic resistive cable consisting of main part in this system.

• 한국가스학회:학술대회논문집
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• 1997.09a
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• pp.223-228
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• 1997

• 한국가스학회:학술대회논문집
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• 1997.09a
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• pp.292-301
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• 1997

• 한국가스학회:학술대회논문집
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• 1998.09a
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• pp.3-8
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• 1998

• 한국가스학회:학술대회논문집
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• 2000.09a
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• pp.157-162
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• 2000