• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07a
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• pp.601-604
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• 2003

The magnetic field generated in the iron core, which is required for the magnetic field to link each coil of the flux-lock type reactor, affects the fault current limiting characteristics of the flux-lock type high-Tc superconducting fault current limiter(SFCL). By applying numerical analysis for equivalent circuit of flux-lock type SFCL, the magnetic field induced in the iron core including currents of each coil was investigated. Through the analysis of magnetic field, we have analyzed that the magnetic field linked the 3rd coil, which is wound in the iron core, prevents the saturation of the iron core, but decreases the impedance of the flux-lock type SFCL.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.289-289
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• 2008

We investigated the operational characteristics of the separated three-phase flux-lock type superconducting fault current limiter (SFCL). The single-phase lock type SFCL consist of two coils, which are wound in parallel through an iron core. The high-$T_c$ superconducting(HSTC) thin film connected in series with secondary coil. The separated three-phase flux-lock type SFCL consist of three single-phase flux-lock type SFCL. In a normal condition, the SFCL is not operate. When a fault occurs, the current of a HSTC thin film exceeds its critical current by fault current, the resistance of the HSTC thin film generated. Therefore fault current was limited by SFCL. The separated three-phase flux-lock type SFCL are operated in fault condition such as the the single line-to-ground fault, the double line-to-ground fault and the triple line-to-ground fault. The experimental results, the SFCL operational characteristics was dependent on fault condition.

• JSTS:Journal of Semiconductor Technology and Science
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• v.11 no.2
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• pp.73-79
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• 2011

This paper describes a reset-free delay-locked loop (DLL) for a memory controller application, with the aid of a hysteresis coarse lock detector. The coarse lock loop in the proposed DLL adjusts the delay between input and output clock within the pull-in range of the main loop phase detector. In addition, it monitors the main loop's lock status by dividing the input clock and counting its multiphase edges. Moreover, by using hysteresis, it controls the coarse lock range, thus reduces jitter. The proposed DLL neither suffers from harmonic lock and stuck problems nor needs an external reset or start-up signal. In a 0.13-${\mu}m$ CMOS process, post-layout simulation demonstrates that, even with a switching supply noise, the peak-to-peak jitter is less than 30 ps over the operating range of 500-1200 MHz. It occupies 0.04 $mm^2$ and dissipates 16.6 mW at 1.2 GHz.

• Journal of Korean Dental Science
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• v.4 no.2
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• pp.85-91
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• 2011

Some treatment methods have been proposed for patients with chronic closed lock of temporomandibular joint. We report a conservative treatment for patients who had chronic closed lock of temporomandibular joint and who did not want surgical treatment. Two patients who had been treated in the Template clinic, Soonchunhyang University Bucheon Hospital, are the subjects of this report. The subjects had chronic closed lock symptom for over 3 months after an onset of locking; conventional therapies had no effect. The subjects were treated by making them wear a Template appliance while sleeping and exercise for 10 hours a day. After periodic follow-up, significant improvement was observed for Template treatment in terms of the maximal mouth opening range. When conventional therapy is expected to be ineffective, The Template appliance can be used as conservative treatment for temporomandibular disorders patients with chronic closed lock of temporomandibular joint.

• Archives of design research
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• v.17 no.1
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• pp.179-190
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• 2004

The human effort to make personal privacy and safety from outer environment has brought the improvement of security system through the technological development. Especially as a apartment dwelling and lifestyle is general, the role and function of door lock system is more important than ever. The research for user-centered approach and design on the door lock system should be implemented under the circumstances. This study has focused on the development of making safety as well as easy interface to design door lock system. The price also is competitive as compared with other door lock products. The goal of this study is to propose the alternatives not only to develop door lock design but also to search the innovative way of locking system design.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.10a
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• pp.86-88
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• 2017

The digital door lock is an electronic door lock that uses a password system and has the function of automatically locking the door when the door is closed, thus eliminating the worry about the door lock. As the technology has gradually developed, various authentication technologies such as semiconductor key system, RFID, and fingerprint recognition have been introduced. However, there is a danger of copying the door lock key, and there are password stealing and infringement. In this paper, we develop a remote control system that can unlock or open a smartphone to supplement the user's risk. The system you are going to develop can use WiFi to check if the door is locked or open on your smartphone, and you can lock or unlock the door remotely.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.31 no.9
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• pp.780-789
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• 2007

Lock-on phenomenon in the wake of a circular cylinder is investigated at the Reynolds number of 360 using direct numerical simulation (DNS). To induce lock-on, a streamwise velocity perturbation with a frequency of twice the natural shedding frequency is superimposed on the free stream velocity. The Reynolds stress distributions are investigated to analyze the streamwise force balance acting on the recirculation region and the results are compared with the previous experimental result. When the lock-on occurs, the pressure force on the recirculation region is shown to increase mainly due to the reversal of the Reynolds shear stress distribution, which is consistent with our previous results using PIV measurement. It is also shown that, with the lock-on, the strength of the primary vortices increases whereas that of the secondary vortices decreases significantly. Further, under the lock-on condition the wavelength of the secondary vortices increases by as much as 2.5 times.

• Proceedings of the IEEK Conference
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• 2000.11b
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• pp.79-82
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• 2000

This paper describes a delay locked loop with selective starting point for use in a high-frequency systems. SSRDLL (selective starting point RDLL) has been simulated in a 0.25$\mu\textrm{m}$ standard n-well CMOS process parameter to realize a fast lock-on time. This DLL is shown to be insensitive to variations in PVTL. The simulated lock time of the proposed SSRDLL is within 4 clock cycles at 333㎒ clock input.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.24 no.2
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• pp.136-140
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• 2011

The fault current limiting characteristics of the flux-lock type superconducting fault current limiter (SFCL) using a transformer winding were investigated. The suggested flux-lock type SFCL consists of two parallel connected coils on an iron core and the transformer winding connected in series with one of two coils. In this SFCL, the high-TC superconducting (HTSC) element was connected with the secondary side of the transformer. The short-circuit experimental devices to analyze the fault current limiting characteristics of the flux-lock type SFCL using the transformer winding were constructed. Through the short-circuit tests, the flux-lock type SFCL using transformer winding was shown to perform more effective fault current limiting operation compared to the previous flux-lock type SFCL without the transformer winding from the viewpoint of the quench occurrence and the recovery time of the HTSC element.

• 한국가시화정보학회:학술대회논문집
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• 2004.11a
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• pp.18-21
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• 2004

Lock-on characteristics of the flow around a circular cylinder performing a rotationally oscillation with a relatively high forcing frequency have been investigated experimentally using flow visualization and hot-wire measurements. Dominant parameters are Reynolds number (Re), amplitude of oscillation $(\theta_A)$, and frequency ratio $F_R=f_f\;/\;f_n$, where $f_f$ is the forcing frequency and if is the natural frequency of vortex shedding. Experiments were carried out under the conditions of $Re=4.14\times10^3,\;\pi/15\leq\theta_A\leq\pi/3$, and $F_R=1.0$. The effects of this active control technique on the lock-on flow regime of the cylinder wake were evaluated through wake velocity measurements and spectral analysis of hot-wire signals. The rotary oscillation modified the flow structure of near wake significantly. The lock-on phenomenon was found to occur in the range of frequency encompassing the natural vortex shedding frequency. In addition, when the amplitude of oscillation is less than a certain value, the lock-on phenomenon was occurred only at $F_R=1.0$. The lock-on range expanded and vortex formation length decreased as the amplitude of oscillation increases. The rotary oscillation generated small-scale vortex structure just near the cylinder surface.