• Journal of the Korean Society for Precision Engineering
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• v.11 no.2
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• pp.65-74
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• 1994

Backcap is an electric remote control system for the operation of directional flow control valves. This paper presents a new type of basckcap system which is characterized by its simple construction. The backcap is essentially a hydraulic cylinder of which the piston is connected to a spool of hydraulic valve and controlled by input current. An inherent feedback is imposed on its mechanism so that no artificial noe is needed. Characteristics of the backcap is verified by stability analysis, transient motion and steady state positioning for step inputs. Design parameter analyses have been executer by some analytical approaches and computer simulations, which lead to their optimal valves. These results contributed to an effective new backcap system and its design strategy.

• Proceedings of the Korean Nuclear Society Conference
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• 1999.05a
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• pp.471-472
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• 1999

• Journal of the Korean Magnetics Society
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• v.12 no.6
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• pp.231-234
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• 2002

Magnetic properties are investigated for top- and bottom-type spin valves of Si/SiO$_2$/NiO(60nm)/Co(2.5nm)/Cu(1.95nm)/Co(4.5nm)/NOL(t nm; Nano Oxide layer). The MR ratios of the bottom-type spin valves with NOL are larger than those of the top-type spin valves. However, the enhancement of the former is lower than the latter. Both of spin-valves also showed almost constant Ap and smaller p. Enhanced MR ratios of spin valves with NOL result mainly from small values of with constant Ap which due to specular diffusive electron scattering at NOL(NiO)/metal interfaces.

• Journal of Biomedical Engineering Research
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• v.22 no.5
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• pp.413-418
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• 2001

We developed shunt valves used to treat patients with hydrocephalus. The valves under development were constant Pressure type ventriculoperitoneal (VP) calves made of silicone elastomer. In vitro experiments showed that our valves had similar Pressure-flow control characteristics to the valved currently available in the market. Our valves also showed competent performance in the 28 days of continuous pumping tests acording to the IS07197 specifications. We artificially inducted hydrocephalus to a 10kg beagle do9. The size of the ventricles of the dog was substantially increased and the dog showed abnormal behavior. After our valve being implanted, the ventricles recovered regular size with the normal behavior observed in the dog. The flow orifice of the shunt valve diaphragm was in the older of 10$\mu$m during calve operation and hence the pressure-flow control characteristics tended to change by a small chance in the valve dimension. Therefore, precision design and manufacturing techniques were necessary for successful operations of the shunt valves .

• Journal of Chest Surgery
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• v.26 no.4
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• pp.282-293
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• 1993

From Sep. 1985 to Dec. 1992, total 1000 cases of open heart surgery [OHS] were performed in the department of Thoracic & Cardiovascular Surgery, Pusan Paik Hospital, College Of Medicine, Inje University.Among the total 1,000 cases of OHS, there were 823 cases with congenital heart diseases [CHD] and 177 cases with acquired heart diseases [AHD]. The age distribution was 9 days [4.0 kg] to 49 years in CHD and 11 to 64 years in AHD, In the 823 cases of CHD, there were 763 acyanotic cases and 60 cyanotic cases. The CHD cases consisted of 520 VSD [63.2 %], 177 ASD [21.5 %], 60 TOF[7.3 %], 27 PS [3.3 %], 17 ECD [2.1%], 7 Valsalva sinus rupture [0.9 %], 4 TGA [0.5 %], 3 Ebstein`s anomaly [0.4%], 3 DORV[0.4%], and others. The corrective operations were applied for congenital heart disease with the result of 2. 8 % hospital mortality. In the 177 AHD, 168 cases were valvular heart diseases, 7 cases were cardiac tumors and one LA thrombus and one annuloaortic ectasia. In the 168 valvular heart diseases, there were 115 single valve replacement cases [16 AVR, 99 MVR], 20 cases of double valve replacement[AVR & MVR], 15 cases of MVR with TVA, and 10 cases of AVR, MVR with TVA. The total implanted prosthetic valves were 199`. In MVR, 66 of St. Jude Medical valves, 78 ofCarpentier-Edward valves, and 5 of Ionescu-Shiley valves were used. In AVR, 38 of St. Jude Medical valves and 12 of Carpentier-Edward valves were used.The hospital operation mortality rate of congenital acyanotic, cyanotic, and acquired heart diseases were 1.6%, 18.3 % and 3.4% respectively. The overall mortality rate was 2.9 % [29/1000].

• Current Industrial and Technological Trends in Aerospace
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• v.7 no.2
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• pp.68-75
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• 2009

Up to date, demands for satellite including communication are increasing. Advanced countries on space technology such as America, Russia, Europe, Japan, China and so on already had secured launch vehicle technology which can insert a large class satellite to proper orbit. The introduction of technologies on the large class launch vehicle including propulsion system is difficult due to the utilization possibility for defensive reason. The acquisition of indigenous technical expertise on the design and manufacture of valves is believed to contribute to the successful local development of valves for propulsion systems and to significant improvement of local technical level of valve design and development. This paper introduces current status of valves developed by other countries as well as valves developed in domestic. The Developed technology of valves may underlie the construction of engine control systems required for the reliable operation of the KSLV-II engine system and propulsion system.

• Nuclear Engineering and Technology
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• v.41 no.1
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• pp.53-62
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• 2009

A set of experiments has been conducted on the performance sensitivity of the passive residual heat removal system (PRHRS) for an advanced integral type reactor, SMART, by using a high temperature and high pressure thermal-hydraulic test facility, the VISTA facility. In this paper the effects of the opening delay of the PRHRS bypass valves and the closing delay of the secondary system isolation valves, and the initial water level and the initial pressure of the compensating tank (CT) are investigated. During the reference test a stable flow occurs in a natural circulation loop that is composed of a steam generator secondary side, a secondary system, and a PRHRS; this is ascertained by a repetition test. When the PRHRS bypass valves are operated 10 seconds later than the secondary system isolation valves, the primary system is not properly cooled. When the secondary system isolation valves are operated 10 or 30 seconds later than the PRHRS bypass valves, the primary system is effectively cooled but the inventory of the PRHRS CT is drained earlier. As the initial water level of the CT is lowered to 16% of the full water level, the water is quickly drained and then nitrogen gas is introduced into the PRHRS, resulting in the deterioration of the PRHRS performance. When the initial pressure of the PRHRS is at 0.1MPa, the natural circulation is not performed properly. When the initial pressures of the PRHRS are 2.5 or 3.5 MPa, they show better performance than did the reference test.

• Journal of Chest Surgery
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• v.19 no.4
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• pp.644-662
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• 1986

Seventy cases of open heart surgery were performed in the department of Thoracic and Cardiovascular Surgery, Pusan Paik Hospital, Inje College, from Oct. 1985 to Oct. 1986. And the results were summarized as follows. 1. Among the 70 cases, there were 48 cases of congenital heart anomalies and 22 cases of acquired rheumatic valvular heart diseases. Age range of the congenital patients was 7 months to 31 years with the mean age of 10 years, and the acquired patients was 18 to 62 years with the mean age of 40 years. 2. The heart-lung machine used for cardiopulmonary bypass was Sarns 7000, 5-head roller pump, and the number and type of oxygenators were 5 of membrane type and 65 of bubble type. For all cases GIK [glucose-insulin-potassium] solution was used as cardioplegic solution for myocardial protection during operation. 3. Among the 48 congenital anomalies, there were 12 cases of ASD group, 29 of VSD group, 3 of ECD, 3 of TOF and one of PDA + MR, and to all of which the appropriate radical operations were applied. 4. Among the 22 acquired valvular diseases, there were 11 cases of mitral valve diseases [MS; 4, MSr; 3, MRs; 4], 3 cases of aortic valve diseases [AR:1, ARs;1, ASr;1], 4 cases of double valve diseases [MRs+TR; 3, MRs+ARs; 1] and 4 cases of triple valve diseases [MSr+ASr+TR; 3, MSr+Ar+TR; 1]. To all the diseased mitral and aortic valves, artificial valve replacement was applied except one [As], in which valve plication was applied. And to all the diseased tricuspid valve, DeVega annuloplasty was applied. 5. The number of replaced artificial valves were 29 in 25 patients [congenital; 3, acquire; 22]. In MVR, 6 of mechanical valves [St. Jude Medical valve; 6] and 15 of tissue valves [Carpentier-Edward valve; 11, lonescu-Shiley valve; 4] were used. In AVR, 6 of mechanical valves [St. Jude Medical valve; 6] and 2 of tissue valves [Carpentier-Edward valve; 2] were used. 6. Postoperative complications were occurred in 12 cases. Among them 11 cases were recovered with intensive cares, but one patient [VSD + Fistula of Valsalva sinus] was expired with low cardiac out put syndrome.

• Journal of the Korean Magnetics Society
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• v.14 no.3
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• pp.109-113
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• 2004

GMR isolator was modeled using a Wheatstone bridge which is profitable for transmitting rectangular wave digital data, and the output voltage characteristics in relation to the input current were investigated in time domain. GMR isolator modeling was divided into two parts, namely magnetic and electric parts. The flow chart of the modeling was drawn in which measured MR curve of the spin valves were incorporated to obtain the electrical voltage output. For magnetic modeling, 3-dimensional model of planar coil was analyzed by FEM method to obtain the magnetic field strength corresponding to the input current. For electric modeling, resistance, inductance and capacitance of the planar coil were calculated and magnetic field waveform was obtained corresponding to the coil current waveform in time domain. Finally, MR-H curves of spin valves and the magnetic field waveform at the spin valves were composited to obtain the output voltage waveform of the isolator. Even though the amplitude of the coil current waveform was increased by 100％, decreased by 90％, or delayed by 10％ of the period compared with the input current, similar transmitted output voltage waveform to the input current waveform was obtained due to hysteretic characteristics of the spin valves at the transmission speed of over 400 Mbit/s.

• Journal of the Korean Institute of Gas
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• v.23 no.5
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• pp.35-43
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• 2019

The safety of industrial valves, which are the core parts of plant facilities, are managed by manpower and there are difficulties because of side area for inspection and limited accessibility due to the nature of facilities. The industrial valves used in plant facilities cause problems such as interrupted production; a loss of life due to leak or explosion of poisonous material and flammable gases, and difficulty in locating accident positions in the event of leakage or failure. Therefore, safety management and control systems based on IoT technology are needed. This study is about the development of risk factor prediction technique among the safety management of industrial valves through IoT- based wireless communication and the development of actuator control system. We have developed IoT-based industrial valve safety management techniques to prevent accidents caused by main risk factors by conducting an analysis of the structural characteristics of valves and an analysis of the causes of main risk factors through review of failure data and literature and an analysis of accident scenarios.