• Nuclear Engineering and Technology
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• v.39 no.2
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• pp.103-110
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• 2007

The High Temperature Gas-cooled Reactor (HTGR) possesses inherent safety features and is recognized as a representative advanced nuclear system for the future. Based on the success of the HTR-10, the long-time operation test and safety demonstration tests were carried out. The long-time operation test verifies that the operation procedure and control method are appropriate for the HTR-10 and the safety demonstration test shows that the HTR-10 possesses inherent safety features with a great margin. Meanwhile, two new projects have been recently launched to further develop HTGR technology. One is a prototype modular plant, denoted as HTR-PM, to demonstrate the commercial capability of the HTGR power plant. The HTR-PM is designed as $2{\times}250$ MWt, pebble bed core with a steam turbine generator that serves as an energy conversion system. The other is a gas turbine generator system coupled with the HTR-10, denoted as HTR-10GT, built to demonstrate the feasibility of the HTGR gas turbine technology. The gas turbine generator system is designed in a single shaft configuration supported by active magnetic bearings (AMB). The HTR-10GT project is now in the stage of engineering design and component fabrication. R&D on the helium turbocompressor, a key component, and the key technology of AMB are in progress.

• Journal of Institute of Control, Robotics and Systems
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• v.17 no.1
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• pp.1-5
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• 2011

The basic signals for electronic engine control are velocity and degree of the engine cam shaft. The CPS sensor used for this signal and magnetic pick-up type CPS sensor is more popular. It is very important thing analyze this signal correctly. If there are some mistakes at the analysis, like a noise, The engine do not working at the best status, it will generate some noise, emit exhaust fumes and waste more gases. In general way to analysis this signal, you use zero-level detector circuit and in order to reduce the error you must use another sensor like a TDC sensor. In this paper, We proposed the analysis method using electronics circuits for magnetic pick-up type CPS sensor. We designed Comparison level detector circuit, Differential circuit and Full-rectifier circuit for detected the Long tooth and Short tooth level correctly without another sensor. We expected it is useful for more reliable engine control.

• Journal of Advanced Marine Engineering and Technology
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• v.9 no.2
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• pp.159-169
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• 1985

The calculation of torsional vibration for marine diesel engine propulsion shafting is normally carried out by equalizing exciting energy to damping energy, or using the dynamic magnifier. But, with these methods, the vibration amplitudes are calculated only for resonance points and vibration amplitudes of other running speeds of engine are determined by the estimation. Recently, many energy-saving ships have been built and on these ships, two-stroke, supercharged, super-long stroke diesel engines which have a small number of cylinders are usually installed. In these cases, the first order critical-torsional vibrations of these engine shaftings appear ordinarily near the MCR speed and the stress amplitudes of their vibration skirts exceed the limit stress defined by the rules of classification society. To predict the above condition in the design stage, the synthesized vibration amplitudes of all orders which are summed up according to their phase angles must be calculated from the drawings of propulsion shaft systems. In this study, a theoretical method to fulfill the above calculation is derived and a computer program is developed according to the derived method. And a shafting system of two-stroke, super-long stroke diesel engine which was installed in a bulk carrier is analyzed with this method. The measured values of this engine shafting are compared with those of calculated results and they show a fairly good agreement.

• Archives of Reconstructive Microsurgery
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• v.25 no.1
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• pp.19-24
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• 2016

Urethral reconstruction is a problematic issue, thus its management can be challenging. Different methods using various materials were introduced for urethral reconstruction. The authors have made some changes in the groin flap surgery, affording more successful urethral reconstruction for defects of long urethra and penile soft tissue. A 45-year-old male requested both functional and cosmetic reconstruction of his defected penis, caused by an iatrogenic urethral injury and chronic infection following removal of paraffin self-injected on the penile shaft. The defect affected the full length of the penile urethra, corpus spongiosum, and prepuce. A groin flap was designed, measuring $28{\times}10cm$. The most distal flap was utilized for the construction of the luminal surface of the neourethra; relaxed length measuring 8 cm, and the lumen wide enough. Competent external meatus and neourethra was confirmed by retrograde cystogram and the patient voided with sufficient urine caliber up to 2 years follow-up. This operative technique has advantages. Donor sites have non-hair bearing skin for the neourethra and minimal or almost notrecognizable donor site morbidity. After surgery, the patient was relieved from voiding difficulties combined with psychological stress. The author would like to introduce a unique approach for the urethral and ventral phalloplasty using the groin flap.

• Applied Microscopy
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• v.51
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• pp.11.1-11.9
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• 2021

Spider capture silk is a natural scaffolding material that outperforms most synthetic materials in terms of its combination of strength and elasticity. Among the various kinds of silk threads, cribellar thread is the most primitive prey-capturing type of spider web material. We analyzed the functional organization of the sieve-like cribellum spigots and specialized calamistral comb bristles for capture thread production by the titanoecid spider Nurscia albofasciata. The outer cribellar surface is covered with thousands of tiny spigots, and the cribellar plate produces non-sticky threads composed of thousands of fine nanofibers. N. albofasciata cribellar spigots are typically about 10 ㎛ long, and each spigot appears as a long individual shaft with a pagoda-like tiered tip. The five distinct segments comprising each spigot is a defining characteristic of this spider. This segmented and flexible structure not only allows for spigots to bend individually and join with adjacent spigots, but it also enables spigots to draw the silk fibrils from their cribella with rows of calamistral leg bristles to form cribellar prey-capture threads.

• Archives of Reconstructive Microsurgery
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• v.7 no.1
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• pp.54-61
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• 1998

Free vascularized fibular is the most usuful bony donor of the long bone reconstruction in reconstructive microsurgical field. It has many benifits such as very strong strut tubular bone, very reliable vascular anatomy with large vascular diameter with long pedicle, minimal donor site morbity too. In that situations of the huge long bone defects in distal femur or proximal tibia, the defective bony shape and strength of the transplanted fibular bone is not enough if only one strut of the fibula is transfered. The bony circulation of the fibula has two ways, one from nutrient artery via peroneal artery through nutrient foramen which makes endosteal arterial network inside of the fibula, another way is periosteal network through outside encircling vascular network of the bone which distributed in muscle sleeves of the fibular diaphysis. Authors modified free vascularized fibular bone graft with transverse osteotomy is made from the anterolateral aspect of the fibular shaft just distal to entry of the nutrient artery. This produces two vascularized bone struts that may be folded pararell to each other but that remain connected by the periosteum and muscle cuff surrounding the peroneal artery and veins. The proximal strut is vascularized by both a periosteal and endosteal blood supply, whereas the distal strut is vascularized by a periosteal blood supply alone. This procedure can call "doule barrel" free vascularized fibular graft. We performed 7 cases of doule barrel fashined fibular transplantation on distal femur and proximal tibial large defects. Average bone union time takes 7 months from that procedure. There were no significant bone union time differences between both proximal and distal struts. After solid union of the transfered double barrel fibular graft, there were no stress fracture in our series. We can propose double barrel free vascualized fibular graft is usuful method in that cases with very large bone defect on large long bones especially metaphyseal defects.

• Tunnel and Underground Space
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• v.16 no.5 s.64
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• pp.357-367
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• 2006

Recently, as the construction of new railway and the relocation of existing line increase, tunnel structures grow longer. The railway fire accidents in long tunnel bring large damages of human life and disaster. The interest of safety in long tunnel have a growing and the safety standard of long tunnel is tightening. For that reason, at the planning of long tunnel, the optimum design of safety facility in long tunnel for minimizing the risks and satisfying the safety standard is needed. For the reasonable design of long railway tunnel considering high safety, qualitative estimation for tunnel safety is required. In this study, QRA (Quantitative Risk Assessment) technique is applied to design of long railway tunnel for assuring the safety function and estimating the risk of safety. The case study for safety design in long railway tunnel is tarried out to verifying the QRA technique for two railway tunnels. Thus, the inclined and vertical shaft for escape way and safety facilities in long tunnel are planned, and the risks of tunnel safety for each case are estimated quantitatively.

• Journal of Advanced Marine Engineering and Technology
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• v.32 no.3
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• pp.430-436
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• 2008

Recently, there are many cases to use a ship's engine performance analyzer(SEPA) to measure pressure in cylinder and top dead center(TDC) of piston of engine, and analyze its performance such as fuel injection time and horsepower as well as wear of piston ring. But, SEPA needs TDC pulses($T(1){\sim}T(n)$) generated when pistons of engine are located to the TDC position ($TDC(1){\sim}TDC(n)$), these pulses are gathered from sensors connected to gear wheel of the propeller shaft in the remote distance from the measurement point. Therefore, operators need a long wire cable(WRC) to TDC detecting sensor to get these pulses, but this method is a very uncomfortable and expensive in case of installation, and it might decrease user's purchase desire. In this paper, we design and fabricate a small and inexpensive MODEM cable(M0C) so that it may be available to transmit TDC pulse generated from sensor in propeller shaft through existing power line. We also verify the facts that this MOC can be applied to SEPA and the effectiveness of the system through the experiments.

• International Journal of Naval Architecture and Ocean Engineering
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• v.9 no.3
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• pp.239-245
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• 2017

As a new technical approach, wave energy converter by using vertical motion of water in the multiple water chambers were developed to realize actual wave power generation as eco-environmental renewable energy. And practical use of wave energy converter was actually to require the following conditions: (1) setting up of the relevant device and its application to wave power generation in case that severe wave loading is avoided; (2) workability in installation and maintenance operations; (3) high energy conversion potential; and (4) low cost. In this system, neither the wall(s) of the chambers nor the energy conversion device(s) are exposed to the impulsive load due to water wave. Also since this system is profitable when set along the jetty or along a long floating body, installation and maintenance are done without difficulty and the cost is reduced. In this paper, we describe the system which consists of a float, a shaft connected with another shaft, a rack and pinion arrangement, a ratchet mechanism, and rotary type generator(s). Then, we present the dynamics model for evaluating the output electric power, and the results of numerical calculation including the effect of the phase shift of up/down motion of the water in the array of water chambers aligned along the direction of wave propagation.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.28 no.1
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• pp.29-34
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• 2016

The friction factor unit was studied to find a more economic alternative compared to the conventional 30 mmAq/m. The pipe and pump for cooling water piping used in a failing were selected, and the friction factor unit was changed to calculate the pipe diameter and the brake shaft power. Based on current electric charges, After the brake shaft power was converted into operational costs based on current electric charges, then an economic analysis was conducted considering that incorporated the initial installation costs and operational costs for the pump. We found that the friction factor unit when using 20 mmAq/m is more economical than that with 30 mmAq/m, if the piping is used for more than 4 years. The small friction factor unit is desirable when the piping is used for quite a long period of time, and the selection of a more economic friction factor unit should considering the period of usage will be important.