• Journal of the Korean Professional Engineers Association
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• v.15 no.2
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• pp.3-15
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• 1982

The study on prevention measures for vibration and excavation of tunnel for the #3, #4, Seoul Subway. In the Seoul subway tunnel blasting, the drilling pattern and prevention method to seismic vibration are as follows as well as for adaptions of NATM, the supportings of roof and wall holes are arranged with control blasting. 1. The blasting is executed basically using the low velocity explosive such as slurry, Nitrate ammonium explosive, and F-I and F-II explosive for control blasting substituting of existing dynamite. 2. The cut holes are arranged with burn cut pattern and also must be arranged with M/S electrical delay caps substituting of ordinary do]ay caps. 3. Jack leg drills are used in Five Job sites and a jumbo drill in one job site. 4. In performance of safety work and in maintenance of building safety. The drilling length for blasting will not exceed 1.20 meter for round so that the vibration value shall carry below 0.3cm/sec. The harmonizing of better powder, better drilling machine and better technique is only the way of improving tunnelling efficiency and less vibration will help the dereasing of accidence.

• Journal of Aerospace System Engineering
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• v.5 no.1
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• pp.13-16
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• 2011

All components such as structure, engine, electrical equipment, wire etc. should have certified qualities and functions for safe flight. The wire like a blood vessel of man is connected with most components and supply a electrical signal or power to them and only certified wire through a lot of tests such as rating, flame resistance, self-extinguishing, protection of EMI etc. must be used in aircraft. In other words, the wire should observe many certification requirements because it is one of the most important components.

• Korean Journal of Acupuncture
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• v.28 no.3
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• pp.53-62
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• 2011

Objectives : Burn is most common adverse events of moxibustion. Various kinds of components influence on the heat stimulation of commercial indirect moxa, but there are not enough investigation about the status. The purpose of this study is to investigate the 6 components to build a base data that is currently available to build a standard of an indirect moxibustion. Methods : The length and weight, density, thickness of the paper disk, diameter of the paper disk, and diameter in the paper disk hole were measured against 6 kinds of commercial indirect cautery. Results : 1. 'Seoam', 'Kihwang' and 'Taegeuk' shows uniform length than the other brands. 2. 'Dongbang', 'Kihwang' and 'Taegeuk' shows uniform weight than the other brands. 3. 'Dongbang', 'Kihwang' and 'Taegeuk' shows uniform density than the other brands. 4. 'Dongbang' and 'Kihwang' shows uniform thickness than the other brands. 5. 'Seoam', 'Dongbang' and 'Taegeuk' shows uniform diameter of disc hole than the other brands. Conclusions : As a result of investigation, 'Dongbang' and 'Kiwhang' indirect moxibustion was identified as a uniform product. This results are considered as an important base materials of the KS through commercial indirect moxibustion.

• Journal of Welding and Joining
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• v.23 no.1
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• pp.69-76
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• 2005

Recently, application of arc welding to galvanized carbon steel sheet is on the increasing Ould in the fields of automobile and construction industries. In arc welding process, zinc is evaporated in weld pool, even under the appropriate welding condition and produce blowhole and/or pit. Zinc gas cause instability of arc and increase spatter and fume. This research is purposed to minimize the heat-input and the formation of porosities in the welded joint of the galvanized carbon steel sheet using variable polarity AC wave pulse MIG welding system. An appropriate welding condition which showed low spatter and good bead appearance was acquired by applying the AC pulse MIG welding machine to DC duplicated MIG welding with the solid wire. When oxygen gas was added to shield gas of MIG welding for galvanized steel sheet, arc length was increased and arc stability was improved. In the AC duplicated welding, the loss of galvanized layer was decreased as the amount of heat-input was decreased when the EN ratio was increased under the condition that average welding current was evenly set.

• Explosives and Blasting
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• v.13 no.4
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• pp.5-27
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• 1995

Korea-America tungsten treaty is not only Earnning Us Dollar but also it was turnning point of tunnelling technology development such as a burn cut. Because 10th of specialist worked at Sangdong mine under treaty. The first of all, Experimental blasting pattern for single free face carried out. As a result it has brought the burden and $charge/m^3$ and also space distance. After the center holes are blasted. Remain of the works was the implementation of bench cut against the openning to make the full sectional are required. $Ca=\frac{A}{SW}$ where as A =ndi=m activated area S = Peripheral length of Charged room Ca = Rock Coefficient di=Holes diameter Later in 1980, The Oynaite Explosive is Replaced into Emulsion & Milli-Second Delay Electric Cap. Seqential Blasting machine were Applied in the Site. The Subway Tunnelling have been worked so Carefully for Vibration and Noise to near Shopping and housing area. We carried out Empirical formula to solve city Envoirement pollution as follow For Granite: $V=KW^{0.57}D^{-1.75}$ For Granite : $V=KW^{0.5}D^{-1.5}$ V=PPV(cm/sec) K=Coefficency D=Distance(m) W=Amount of power/delay(kg)

• Journal of the Korean Society of Propulsion Engineers
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• v.8 no.2
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• pp.95-101
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• 2004

An experimental investigation was conducted to investigate the effects of the equivalence ratio and air mass flux on the combustion efficiency in a solid fuel ramjet used fuel grains which were highly loaded with boron carbide. Combustion efficiency increased with increasing equivalence ratio (grain length), and decreasing air mass flux. Higher inlet air temperature produced higher combustion efficiencies, apparently the result of enhanced combustion of the larger boron particles those burn in a diffusion controlled regime. Short grains which considered primarily of the recirculation region produced larger particles and lower combustion efficiencies. The result of the normalized combustion efficiency increased with inlet air temperatures coincident with the result of the Brayton cycle thermal and the total efficiency relating to the heat input.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.05a
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• pp.177-180
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• 2009

A Possibility of combustion instability on longitudinal mode has a high level at large scale of L/D. Solid propellant has a metal particle and a grain of control to pressure oscillation. Solid rocket motor in slotted-tube grain controls pressure oscillation of longitudinal mode. If slot length is shot, pressure oscillation of longitudinal mode is amplified by cylinder part after middle phase of total burn time. A study has analyzed pressure oscillation of longitudinal mode at spectrum and acoustic modal analysis at pressure of result on static firing test.

• Journal of Radiation Protection and Research
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• v.36 no.4
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• pp.174-182
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• 2011

With the reactor operation conditions - 4.3 wt% $^{235}U$ initial enrichment, burn-up 55,000 MWd/MTU, average power 34 MW/MTU for three periods burned time for 539.2 days per period and cooling time for 100 hours after shut down, to set up the condition to determine the minimum height (depth) of spent fuel storage pool to shut off the radiation out of the spent fuel storage pool and to store spent fuels safely, the dose rate on the specific position directed to the surface of spent fuel storage pool induced by the neutron and gamma-ray from spent fuels are evaluated. The length of spent fuel is 381 cm, and as the result of evaluation on each position from the top of spent fuel to the surface of spent fuel storage pool, it is difficult for neutrons from spent fuels to pass through the water layer of maximum 219 cm (600 cm from the floor of spent fuel storage pool) and 419 cm (800 cm from the floor of spent fuel storage pool) for gamma-ray. Therefore, neutron and gamma-ray from spent fuels can pass through below 419 cm (800 cm from the floor) water layer directed to the surface of spent fuel storage pool.

• Proceedings of the Korean Nuclear Society Conference
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• 1996.05d
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• pp.101-106
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• 1996

For the application of the neutron flux mapping, an accurate calculation of the sensitivity is required because the sensitivity is proportional to the neutron flux density. Sensitivity is defined as the current per unit length per unit neutron flux and it mainly depends on the depression factor(f), the escape probability from the emitter($\varepsilon$1) and the charge build-up factor of the insulator layer(c). A Monte Carlo simulation was accomplished to calculate the sensitivity of rhodium emitter material and alumina(Al$_2$O$_3$) insulator with a cylindrical geometry, based on the (n,${\beta}$) interaction and on other interaction including the secondary electron generation for the more accurate estimation of the sensitivity. From the simulation results, factors fur the sensitivity were accurately calculated and compared with other theoretical and experimental values. In addition, the sensitivity linearly increases and saturates as the emitter radius increases. The accomplished method is useful in the analysis for the change of SPND sensitivity as a function of burn-up and in the optimum design of SPND.

• Journal of Trauma and Injury
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• v.36 no.4
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• pp.425-430
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• 2023

Axillary defects need pliable, vascular tissue to cover the critical structures traversing the axilla and to allow near-normal range of motion in the shoulder. Although local flaps are the first choice, free tissue transfer is a good option when local tissues are injured or scarred. Herein, we report two cases of axillary defects that were reconstructed using anterolateral thigh free flaps. One was a post-electric burn axillary defect for which a thoracoacromial pedicle was used as the recipient, and the other was a posttraumatic axillary defect with the transverse cervical vessels as the recipient. In both patients, the flap survived well with no complications and resulted in adequate functional recovery. In large defects of the axilla with a scarcity of local tissues, free flaps can yield optimal results. The proper selection of recipient vessels and a donor flap with adequate pedicle length impact the outcomes of such reconstruction.