• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2002년도 학술대회지
• /
• pp.647-650
• /
• 2002

A thermoacoustic refrigerator, using a resonant standing acoustic wave, has been built. It employs a loudspeaker to sustain a standing wave in a resonance tube. The stack of plates is 0.075mm-thick plastic sheet(Mylar), spirally wound to make a 40mm-diameter assembly 80mm long. and two heat exchanger are installed. The refrigerant is Helium gas. The description of thermoacoustic refrigerator are presented. The directly measured performance of the resonator. Tc/Th ( temperature ratio ) and $COP/COP_{c}$, (normalized by carnot's COP ) are plotted versus the thermal load Q applied to the cold end, for various speaker power.

• Journal of Mechanical Science and Technology
• /
• 제14권4호
• /
• pp.426-432
• /
• 2000

The development of a low-pollution burner is important for saving energy and preserving the environment. A low-pollution burner can be produced by lean-mixture combustion and general combustion technology. The flammable limit of premixed flame is narrower than that of diffusion flame. Producing a lean mixture of fuel results in an effective combustion condition, which in turn produces high load and low pollution. In this study, it was found that the influx of $Q_2$ had an effect on extending the lean flammable limits and flame stabilization in a doubled jet burner. And the flame, consisting of small eddies, can be stabilized by the nozzle neck phenomena.

• 제어로봇시스템학회논문지
• /
• 제13권3호
• /
• pp.268-272
• /
• 2007

These days many scientists make studies of feedback control system for stability on non-linear state and for the maneuver of flying objects. These feedback control systems have to satisfy trajectory condition and angular conditions, that is to say, controllability and stability simultaneously to achieve mission. In this paper, a design methods using model based control system which consists of spiral predictive model, Q-function included into generalized-work function is shown. It is made a clear that the proposed algorithm using SPM maneuvers for controllability and stability at the same time is successful in attaining our purpose. The feature of the proposed algorithm is illustrated by simulation results. As a conclusion, the proposed algorithm is useful for the control of moving objects.

• 한국해양공학회:학술대회논문집
• /
• 한국해양공학회 2000년도 추계학술대회 논문집
• /
• pp.63-67
• /
• 2000

Up to this day, Most studies of hydroelasticity are inclined to frequency domain atnlysis. Thos amlysis Q the landing, take-4, and dropping of airaqft on a structure. So, the concern of this prrper is a tra a VLFS subjected to dymmic lazd induced by airplane larndirrg and take-off. To predict added mass, dampr exciting force, the source-dipole distribution method were used The responses are accomplished by Fdoimain analysis method is based on Newmark $\beta$ method to pursuit time step pnzcedure taking advantage function for hvdrodvnumic effects.

• 대한수학회보
• /
• 제33권4호
• /
• pp.503-512
• /
• 1996

In this paper we investigate a relation between the multiplicity of solutions and source terms in a nonlinear suspension bridge equation in the interval $(-\frac{2}{\pi}, \frac{2}{\pi})$, under Dirichlet boundary condition $$ (0.1) u_{tt} + u_{xxxx} + bu^+ = f(x) in (-\frac{2}{\pi}, \frac{2}{\pi}) \times R, $$ $$ (0.2) u(\pm\frac{2}{\pi}, t) = u_{xx}(\pm\frac{2}{\pi}, t) = 0, $$ $$ (0.3) u is \pi - periodic in t and even in x and t, $$ where the nonlinearity - $(bu^+)$ crosses an eigenvalue $\lambda_{10}$. This equation represents a bending beam supported by cables under a load f. The constant b represents the restoring force if the cables stretch. The nonlinearity $u^+$ models the fact that cables expansion but do not resist compression.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2002년도 전력전자학술대회 논문집
• /
• pp.734-738
• /
• 2002

In this paper, a novel wireless parallel operation algorithm of N+1 redundant UPS system with no control interconnections is presented. The load sharing of multiple UPS modules are controlled by Q-V droop and $P-\delta$ droop algorithm. This algorithm compensates for inverter parameter variation and line impedance imbalances with wireless auto-tuning method. And to increase the reliability of transient characteristic under parallel operation, a virtual injected Impedance is proposed to decrease a circulation current between inverter modules. Simulation results are provided to prove the novel wireless algorithm.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2002년도 전력전자학술대회 논문집
• /
• pp.739-742
• /
• 2002

This paper is to see the availability of electrical signatures as a means for evaluating performance of MOVs which are extensively used in safety-related systems in nuclear plants. To estimate motor torque, two methods such as d-q frame conversion and air-gap method are suggested and estimated results are compared with measured values. The error between measured and estimated torques is within acceptable error bound with below $1\%$ under varied load. Frequency domain analysis of calculated torque has been done as well. It is shown that monitoring of peak frequency could give useful clues to detect anomalies of MOV.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2002년도 전력전자학술대회 논문집
• /
• pp.612-617
• /
• 2002

To provide beginner with the standard current information on the $\alhpa-\beta$ reference frame of nonlinear load, this paper has focused on the simulation works using MATLAB/SIMULINK in case of current source thyristor controlled rectifier The various $\alhpa-\beta$ components of current/power components are induced by the p-q theory, the results are represented waveforms and trajectories on the $\alhpa-\beta$ reference frame. The compensation effect according to each of the compensating reference components are described.

• 한국농공학회지
• /
• 제43권6호
• /
• pp.163-173
• /
• 2001

This study describes the characteristics of concentrations of pollutants such as total nitrogen(T-N), total phosphorous(T-P), and chemical oxygen demand(COD) at paddy areas during 2-year irrigation periods. The most common order in average concentrations of T-P and COD is podded water > irrigation(or drainage) water > percolated water. Most of pollutants concentrations in drainage water are lower than those in irrigation water after early July due to large uptake of pollutants by rice crop and denitrification. The exponential L (load)-Q(discharge) equations for classified irrigation periods are significant at 0.001 level for irrigation and drainage waters. For drainage water, the concentrations of T-N and COD slightly decrease with discharge, while the T-P concentrations slightly increase with discharge.

• Journal of Communications and Networks
• /
• 제4권2호
• /
• pp.118-127
• /
• 2002

This paper proposes a new scheme - parallel control scheme with feedback control (PCFC) for ABR services in ATM networks. The information from a source is split into a number of streams, for delivery over separate parallel connections with particular coding. At the receiver, the original information is reconstructed by the received packet from the parallel connections. The effects of PCFC on the network performance are due to two factors: Traffic splitting and load balancing. By combinations of analysis and simulation, this paper studies the implications of PCFC for how the ABR parameters should be scaled and the advantages of PCFC compared with other existing schemes.