• 한국군사과학기술학회지
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• 제22권5호
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• pp.625-636
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• 2019

Recently, research on projectiles with wings for precision guidance is actively underway. In this study, we analyzed how the tail fins attached to the projectile affect the base drag. Aerodynamic analysis was performed with RANS(Reynolds Averaged Navier-Stokes) equations using FLUENT, a commercial CFD(Computational Fluid Dynamics) code. Through the aerodynamic analysis, the base drag characteristics of the projectile by parameters (number, length, thickness, position, shape of tail fin) were investigated. The results of this study are expected to be applicable to aerodynamic design of tail fins mounted on projectiles.

• Archives of Pharmacal Research
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• 제29권4호
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• pp.310-317
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• 2006

We investigated the effects of trinitrobenzene sulfonic acid (TNBS), an amino-group reagent, on the human ether-a-go-go-related gene (HERG) $K^+$ channels expressed in Xenopus oocytes. TNBS neutralizes the positively charged amino-groups of peptide N-terminal and lysine residues. External application of TNBS at 10 mM for 5 min irreversibly shifted the curves for currents at the end of the pulse and tail currents of HERG to a more negative potential and decreased the maximal amplitude of the $I_{tail}$ curve $(I_{tail,max})$. TNBS had little effect on either the activated current-voltage relationship or the reversal potential of HERG current, indicating that TNBS did not change ion selectivity properties. TNBS shifted the time constant curves of both activation and deactivation of the HERG current to a more hyperpolarized potential; TNBS's effect was greater on channel opening than channel closing. External $H^+$ is known to inhibit HERG current by shifting $V_{1/2}$ to the right and decreasing $I_{tail,max}$. TNBS enhanced the blockade of external $H^+$ by exaggerating the effect of $H^+$ on $I_{tail,max}$, not on $V_{1/2}$. Our data provide evidence for the presence of essential amino-groups that are associated with the normal functioning of the HERG channel and evidence that these groups modify the blocking effect of external $H^+$ on the current.

• 대한조선학회논문집
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• 제55권3호
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• pp.252-264
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• 2018

The calculation of steady-state cavitating flows around Supercavitating Underwater Bodies (SUB's), which consist of a circular disk head (cavitator), a conical fore-body, a cylindrical middle-body and either a boat-tail or a flare-tail, are carried out. To calculate the axisymmetric cavitating flow, used is a commercial computational fluid dynamics code based on the finite volume method, Fluent. From the analysis of numerical results, the cavity and drag, affected by the fore-body and tail of the SUB's, are investigated. Firstly, the effect of the fore-body shape is investigated with the same disk cavitator and a cylindrical rear-body of fixed diameter. Then with the same cavitator and a fixed fore-body, the effect of the rear-body shape is investigated. Before the cavity generated by the cavitator covers the slant of fore-bodies sufficiently, the larger the cone angle of the fore-body(i.e., the shorter the slant length), the larger the drag and the slower the development of cavity. After the cavity covers the fore-body completely so that the pressure drag component of the body is vanished, the characteristics of drag-velocity curves are identical. Also, as the tail angle is bigger, the cavity generated by the cavitator is suppressed further and the drag becomes larger. The peak of the drag appears for the flare-tail, i.e., when the tail angle is positive(+). On the contrary, the trough of the drag appears for the boat-tail, i.e., when the tail angle is negative(-). When the tail angle is 5 degrees, the peak of the drag appears at the body speed of 80m/s and the value of the drag is 43% larger than that at the design speed of 100m/s. When the tail angle is -5 degrees, the trough of the total drag appears at 75m/s and that drag is 30% smaller than that of the cavitator, which means the rest of the body has a negative drag.

• 센서학회지
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• 제29권2호
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• pp.82-88
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• 2020

In this paper, we propose a complementary metal-oxide semiconductor (CMOS) binary image sensor with a gate/body-tied (GBT) p-channel metal-oxide-semiconductor field-effect transistor (PMOSFET)-type photodetector using a double-tail comparator for high-speed and low-power operations. The GBT photodetector is based on a PMOSFET tied with a floating gate (n+ polysilicon) and a body that amplifies the photocurrent generated by incident light. A double-tail comparator compares an input signal with a reference voltage and returns the output signal as either 0 or 1. The signal processing speed and power consumption of a double-tail comparator are superior over those of conventional comparator. Further, the use of a double-sampling circuit reduces the standard deviation of the output voltages. Therefore, the proposed CMOS binary image sensor using a double-tail comparator might have advantages, such as low power consumption and high signal processing speed. The proposed CMOS binary image sensor is designed and simulated using the standard 0.18 ㎛ CMOS process.

• 한국정밀공학회지
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• 제21권12호
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• pp.127-132
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• 2004

It is very important to find out causes of strip pinching for the high quality of products and fer the stable operation of rolling system. We have examined the strip pinching from three points of view to find out the causes of strip pinching in rolling system: strip shape, rolling operation conditions, and behavior of strip. Wedge, off center, and difference of rolling force through CMD(Cross machine direction) are found to possibly provide major initial causes of strip pinching. Generally strip pinching occurred in the tail of strip. Thus, computer simulations by using a FEM code were also carried out to find out the initial mechanism of strip pinching depending upon the force and geometric boundary conditions at the time of strip tail rolling. The strong compression force effect due to the sudden release of strip tail from the work roll and non-uniform strip tail shape (ex. Fish tail) across the CMD were found to provide possible major causes of strip pinching.

• 한국환경보건학회지
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• 제24권1호
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• pp.24-31
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• 1998

This study was performed to investigate the difference in species of test fish on the determination of short-term bioconcentration factor in zebrafish(Brachydanio rerio), red sword tail(Xiphophorus hellieri) and goldfish(Carassius auratus). Experimental concentrations of carbamates were 0.05 and 0.10 ppm and chlorothalonil were 0.005 and 0.01 ppm for 3 and 5 days, respectively. This paper reports the measured BCF value on pesticides in various species of test fish, under steady state, and examined correlation between the BCF value and depuration rate constant or LC$_{50}$ or lipid content. Carbamates and chlorothalonil concentration in fish extract and BCF of carbamate and chlorothalonil were increased as incresing test concentration. Carbamates concentration in fish extract and BCF of carbamate were decreased as incresing test period, but chlorothalonil concentration in fish extract and BCF of chlorothalonil were increased as prolonging test period. Determined pesticide concentration in fish extract and BCF were highest in red sword tail, and followed by goldfish, and zebrafish. Determined depuration rate constant were highest in zebrafish, and followed by goldfish, and red sword tail. 96hr-LC$_{50}$ were highest in red sword tail, and followed by zebrafish, and goldfish. Lipid compositions were highest in red sword tail, and followed by goldfish, and zebrafish. Therefore, it is suggested that the difference of BCF between each pesticide due to those of lipid composition of fish and deputation rate constant, while LC$_{50}$ have no effect on BCF.

• 한국항공우주학회지
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• 제36권3호
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• pp.211-219
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• 2008

본 연구에서는 삼차원 비정렬 비점성 유동 해석 코드를 이용하여 전투기 형상의 외부 장착물이 꼬리 날개에 미치는 공력 간섭효과에 대한 연구를 수행하였다. 수치적 기법으로는 격자점 중심(vertex-centered)에 기초한 유한체적법과 시간 적분을 위한 내재적인 point Gauss-Seidel 반복 계산법을 사용하였다. 해석 코드의 검증을 위해 전투기 형상에 대한 정상 유동 계산을 수행하였으며 결과를 실험 데이터와 비교하였다. 외부 장착물의 후류(wake)를 정확히 포착하기 위해 예상되는 후류 영역에 대해 국부적인 격자 조밀화를 수행하였으며 천음속 영역에서의 비정상 유동 해석을 통해 외부 장착물에서 발생하는 후류가 수평꼬리날개에 미치는 간섭효과를 확인하였다. 공력 간섭효과를 감소시키기 위한 대안으로는 뒷전 플랩 꺽임각(trailing edge flap deflection)을 고려하였으며 이에 대한 정량적인 감소효과를 제시하였다.

• Journal of Acupuncture Research
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• 제34권2호
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• pp.61-74
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• 2017

Objectives : This study was carried out to evaluate analgesic effects of Zanthoxylum bungeanum Maxim (ZM) pharmacopuncture on formalin-induced pains in Sprague-Dawley (SD) rats and ICR-mice. Methods : The subjects were divided 8 weeks aged rats with constant pain sensitivity into five groups; normal (treated with normal saline at Taegye (KI3) and before injected with normal saline at hindpaw), Con-1 (treated with normal saline at KI3 before injected with formalin at hindpaw), Lido-1 (treated with lidocaine at KI3), ZMWG-1 (treated with Hot water extraction pharmacopuncture of Zanthoxylum bungeanum Maxim at KI3), ZMEG-1 (treated with ethanol extraction pharmacopuncture of Zanthoxylum bungeanum Maxim at KI3). After 35 minutes, we measured ultrasonic vocalization (USV) and enzyme activities of both Aspartate aminotransferase (AST), Alanine aminotransferase (ALT) in rat serum. In addition, Tail flick test is performed by injecting ICR mice at 5 weeks of age. And it classified into 4 groups (Con-2, Lido-2, ZMWG-2, ZMEG-2) according to the kind of drug (normal saline, lidocaine, ZMW, ZME). After each drug injection, we examined the reaction by placing the tail in water at $50^{\circ}C$. Results : ZME had analgesic effects in the early and late phase of USV during the formalin test. There were no significant differences between ZMEG-1 and Lido-1 in early and late phase of USV. Also, No significant differences observed in serum AST and ALT activity in ZMWG-1 and ZMEG-1 compared with Con-1. For tail-flick test, analgesic effect on warmth significantly increased in Lido-2 and ZMEG-2 compare to that of Con-2. Conclusion : ZME pharmacopuncture had analgesic effects on formalin-induced pain without liver toxicity. Also, tail-flick test suggest that ZME pharmacopuncture could be useful technique on analgesic effect on warmth and treatment of pains.

• Journal of Welding and Joining
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• 제17권4호
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• pp.69-75
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• 1999

Spot welding has been used in the sheet metal joining processes because of its high productivity and convenience. In this study, predicting methods of fatigue life of spot welded joint have been investigated and fatigue and static tests were conducted with the peel-tension specimens using cold rolled steel plate(SPCC). Fatigue life of peel-tension spot welded joint was influenced by tail effect. Fatigue life evaluation using modified stress index parameter, considering the effective eccentric length, can predict the life more exactly than conventional stress index parameter.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 춘계학술대회논문집
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• pp.217-220
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• 2005

Zero tail type mini excavator is small in size and capacity compared with medium or large excavator. Therefore noise and heat problems are major issues in design due to layout of each components such as engine and hydraulic module. It is necessary to assure reduction of noise and vibration in construction machine, due to be enforced regulation for high noise construction machinery at home and abroad. The objective of this study is to provide basic data which is apply to predict noise effect in detail design stage by estimating noise of cabin for zero tail type mini excavator.