• Nuclear Engineering and Technology
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• v.53 no.3
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• pp.804-811
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• 2021

The T-junction exists widely in industrial engineering, especially in nuclear power plants, which plays an important part in nuclear power reactor thermal-hydraulics. However, the existing prediction models of the liquid entrainment are mainly based on the small branches or small breaks while there are a few researches for large branches (d/D > 0.2). Referring to the classical models about the onset of liquid entrainment of the T-junction, most of previous models regard liquid as ideal working fluid and ignore surface tension. This paper aims to study the effect of surface tension on the liquid entrainment, and develops an improved model based on the reasonable assumption. The establishment of new model employs the methods of force analysis, dimensional analysis. Besides, the dimensionless Weber number is adopted innovatively into the model to show the effect of surface tension. What is more, in order to validate the new model, three kinds of working fluids with different surface tensions are creatively adopted in the experiments: water, silicone oil and ethyl alcohol. The final results show that surface tension has a nonnegligible effect on the onset of liquid entrainment in large branch T-junction. The new model is well matched with the experimental data.

• Convergence Security Journal
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• v.14 no.6_1
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• pp.57-63
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• 2014

Even though the historical changes of the Cold War, they does not release the Cold War structure in Korean peninsula. And continues North Korea's provocations against South Korea. A factor of instability in Northeast Asia is the causing catastrophic inter-Korean relations and North Korea's Yeonpyeong shelling and provocation of the Cheonan battleship sinking by an explosion. These behaviors have been committed by among the North Korea military. North Korea's provocations made by a complex decision-making system in the United States and North Korea and South Korea. North Korea's aggressive military actions are conducted under the North Korean political system of strategies unification of the Korean peninsula. It has a duality of continuity and change, depending on the situation of a foreign policy in North Korea. If North Korea want maintain structure of their country, they should change the national policy and strategy, tactics and the military action type. North Korea should be a member of international community. As one of the country in the world, North Korea create economic power, nuclear tensions break, and participate in the international community for the peace.

• Journal of National Security and Military Science
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• s.13
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• pp.43-81
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• 2016

Security environment we face in the Korean Peninsula is unexpectable. Tensions between Seoul and Pyeongyang and its threats are continuously evolving. Kim Jung Un will keep on conducting provocations and DPRK's isolation will result uncertainty to their objective and intention. KPA is centered on ground forces with conventional weapons but they possess modernized missiles and nuclear capabilities. What's more concerning is that North Korea continuously pursue and develop nuclear weapons and missile capabilities. Pursuing defense reform is inevitable for the ROK to deal adequately against the security threats posed by the North and to prepare for the environment of future warfare. If we are satisfied with the current capabilities then our military capabilities and security status will retrogress. We have to reorganize our units to make a small but FMC, smart military organization. Organization analysis is an urgent issue for reorganizing units. However, it isn't an easy task to reform an organization. There are vague parts for analysis and strong resistance from the people within the organization. Therefore should not focus on the reduction of people and the organization. Organization reform should be done with the acknowledgement of most of the personnel and should focus on the task and its method. These should be reflected to the organization analysis.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.5
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• pp.1102-1112
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• 2012

The policy of the United States is a Korean Peninsula free of all nuclear weapons. The United States government was considering the possibility of military action to eliminate the North Korean nuclear threat. Talk of military action peaked from mid-1993 through mid-1994. Such an attack might have led directly to a Korean war. At that time the nuclear crisis solutioned by North Korea-United States negotiation and ROK-United States alliance. PSI's purpose is to prevent or at least inhibit the spread of weapons of mass destruction, their delivery systems, and related materials to and from states and non-state actors whose possession would be a serious threat to global or regional security. The most controversial activity of PSI is interdiction. North Korea has expressed grave concern over the initiative, stating that it has a sovereign right to develop, deploy, and export weapons, and that it would view any interdiction of its ships as a declaration of war. If South Korea is to execute interdiction North Korean ships expect tensions to increase dramatically on the peninsula with North Korea doing something quite provacative in response. South Korea cannot help approaching PSI with great caution, since it has to consider the ROK-United States alliance, and inter-Korean relations.

• The Korean Journal of Nuclear Medicine
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• v.18 no.1
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• pp.45-53
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• 1984

The purpose of this study is to observe the changes of pulmonary capillary permeability and various hemodynamic parameters before and after Positive End-Expiratory Pressure(PEEP) in Adult Respiratory Distress Syndrome (ARDS). Using a canine oleic acid induced ARDS model, we measured the pulmonary capillary permeability with a slope of lung: heart radioactivity ratio, hemodynamic parameters with Swan-Ganz catheter and blood gas tensions. 1) In normal and ARDS dogs, the PEEP didn't significantly influence the slope of lung: heart radioactivity ratio. But in ARDS group the slope index was increased compaired with that of control group (p<0.05). 2) Also in ARDS group, $PaO_2$ was significantly decreased, and $PaCO_2,\;PvCO_2$, MPAP, $AaDO_2$, Qs/Qt were significantly increased compared with those of control group (p<0.05). 3) In normal dogs, the PEEP didn't influence blood pH or gas tension, $AaDO_2$, Qs/Qt, or hemodynamics. 4) In ARDS dogs, however, the PEEP significantly increased $PaO_2$ and decreased $AaDO_2$, Qs/Qt (p<0.05).

• Strategy21
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• s.34
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• pp.58-92
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• 2014

Even after S. Korea took 5.24 Measure(24 May 2014), N. Korea has not stopped raising provocations such as the shelling of Yeonpyeong Island, electronic and cyber attacks. To make matters worse, the communist country lunched long-range missiles(twice) and conducted 3rd nuclear test, escalating tensions which could possibly lead to an all-out war. Korean Government failed to respond properly. However, escalation into an all-out war was deterred by the CFC immediately carrying out its peacetime duty(CODA). The US made a rapid dispatch of its augmentation forces(Aircraft carrier, nuclear-powered submarine, strategic bomber, F-22) to the Korean Peninsula. In recognition of the importance of the Combined Forces Command, since May 2013 the Park Geun-Hye Administration has been pushing ahead with re-postponement of Wartime Operational Control Transfer(which initially meant the disassembling of the CFC as of 1 December 2015) More recently, there has been a series of unusual indicators from the North. Judging from its inventory of 20 nuclear weapons, 1,000 ballistic missiles and biochemical weapons, it is safe to say that N. Korea has gained at least war deterrence against S. Korea. Normally a nation with nuclear weapons shrink its size of conventional forces, but the North is pursuing the opposite, rather increasing them. In addition, there was a change of war plan by N. Korea in 2010, changing 'Conquering the Korean Peninsula' to 'Negotiation after the seizure of the Greater Seoul Metropolitan Area(GSMA)' and establishing detailed plans for wartime projects. The change reflects the chain reaction in which requests from pro-north groups within the South will lead to the proclamation of war. Kim, Jeong-Un, leader of N. Korean regime, sent threatening messages using words such as 'exercising a nuclear preemptive strike right' and 'burning of Seoul'. Nam, Jae-June, Director of National Intelligence Service, stated that Kim, Jung-Un is throwing big talks, saying communization of the entire Korean Peninsula will come within the time frame of 3 years. Kim, Gwan-Jin, Defense Minister, shared an alarming message that there is a high possibility that the North will raise local provocations or a full-fledged war whenever while putting much emphasis on defense posture. As for the response concept of the Korean Government, it has been decided that 'ROK·US Combined Local Provocation Counter-Measure' will be adopted to act against local provocations from the North. Major provocation types include ▲ violation of the Northern Limit Line(NLL) with mobilization of military ships ▲ artillery provocations on Northwestern Islands ▲ low altitude airborne intrusion ▲ rear infiltration of SOF ▲ local conflicts within the Military Demarcation Line(MDL) ▲ attacking friendly ships by submarines. Counter-measures currently established by the US involves the support from USFK and USFJ. In order to keep the sworn promise, the US is reinforcing both USFK and USFJ. An all-out war situation will be met by 'CFC OPLAN5027' and 'Tailored Expansion Deterrence Forces' with the CFC playing a central role. The US augmentation forces stands at 690,000 troops, some 160 ships, 2,000 aircraft and this comprise 50% of US total forces, which is estimated to be ninefold of Korean forces. The CFC needs to be in center in handling both local provocations and an all-out war situation. However, the combat power of S. Korean conventional forces is approximately around 80% of that of N. Korea, which has been confirmed from comments made by Kim, Gwan-Jin, Defense Minister, during an interpellation session at the National Assembly. This means that S. Korean forces are not much growing. In particular, asymmetric capabilities of the North is posing a serious threat to the South including WMD, cyber warfare forces, SOF, forces targeting 5 Northwestern Islands, sub-surface and amphibious assault forces. The presence of such threats urgently requires immediate complementary efforts. For complementary efforts, the Korean Government should consider ① reinforcement of Korean forces; putting a stoppage to shrinking military, acquisition of adequate defense budget, building a missile defense and military leadership structure validity review, ② implementation of military tasks against the North; disciplinary measures on the sinking of ROKS Cheon-an/shelling of Yeonpyeong Islands, arrangement of inter-Korean military agreements, drawing lessons from studies on the correlation between aid for N. Korea, execution of inter-Korean Summit and provocations from the North, and ③ bolstering the ROK·US alliance; disregarding wartime operational control transfer plan(disassembling of CFC) and creation of a combined division.

• Korean Journal of Legislative Studies
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• v.24 no.1
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• pp.5-29
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• 2018

This paper aims at making an assessment about the first year of the Moon Jae-in government. President Moon was elected amid political insecurity over the impeachment of then-president Park Geun-hye. However, the Moon administration settled in fairly smoothly despite no transition period of presidential power. Political and economic stability was soon restored, and the tensions between the US and North Korea over the North's nuclear weapons program were, to some extent, managed along with the agreement of the North-South summit and the US-North Korea summit. Pyeongchang hosted the 2018 winter olympics and paralympics successfully. Moon continued very positive approval ratings of higher than 70%. However, he has something to be desired. His leadership seems to rely heavily on a limited number of close staff in the Blue House, alienating the governing the Minjoo Party of Korea. He should build better relationship with opposition parties particularly given a divided government. Rectification of the lingering negative practices should also produce institutional solutions. Above all, Moon should carefully watch out to prevent scandals over corruption and power abuse around him and his family, which would lead to a precipitous decline of the approval ratings and the abrupt weakening of the leadership.