• 인삼약초
• /
• v.4 no.3 s.13
• /
• pp.92-97
• /
• 2006

경희대학교 한약학과 학생회장 신재석(3학년)씨는 다양한 사회생활을 하다가 뜻한바가 있어 한약학과에 재입학하여 학생회 일을 맡고 있다.한약학과에 대한 구체적인 설명과 학과과정 그리고 다양한 동아리활동에 대한 정보 그리고 전국한약학과 학생협의회를 5月에 개최하는 등의 정보를 인터뷰형식으로 양정화(경희대학교 한약학과 문화부장)씨가 알기 쉽게 집필해 주셨다.

• Proceedings of KOSOMES biannual meeting
• /
• 2006.11a
• /
• pp.239-244
• /
• 2006

As an effective means to convey crushed materials from seabed to onboard ship, air-lift pump provides a reliable mechanism due to its simple configuration and easy-to-operate principle. The present study is focused on fundamental investigation of related performance through analysis program based on the gas-liquid two-phase flow in circular pipes. It is summarized as important result that an optimum air mass flow rate exists for the maximum lifted liquid mass flow rate in terms of a given submergence rates.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.37 no.6
• /
• pp.599-605
• /
• 2013

The characteristics of centrifugal pump performance according to fluid viscosity change were studied experimentally. A small volute pump with low specific speed was tested by changing the viscosity of an aqueous solution of sugar and glycerin, which is considered a Newtonian fluid. After finishing the test, the total head, shaft horsepower, and pump efficiency were compared with those of a water pump. The results are summarized as follows: (1) when the fluid viscosity is increased, the shut-off head shows very little change but the total head decreases gradually as the flow increases, and this makes the H-Q curve leaning rapidly, and (2) when the fluid viscosity is increased, the shaft horsepower shows very little change at the shutoff condition; however, the shaft horsepower increases more rapidly with an increase in the flow and viscosity.

• The Journal of Engineering Geology
• /
• v.18 no.4
• /
• pp.439-446
• /
• 2008

We have developed a method to evaluate pumping rates from a system of pumping-well family. For a given system actual pumping rates depend on pump characteristics and the sum of the static head and the dynamic head. The static head is the elevation difference between the natural groundwater level and the outlet of the pipeline that connects all the wells. Major components of the dynamic head are groundwater drawdown in the well and pipeline head loss. The dynamic head and the pump characteristics depend on the pumping rates. Actual pumping rates are determined at the intersections of the system total-head curves and the pump characteristic curves. The Newton-Raphson's method is used to solve the nonlinear simultaneous equations. The method is applied to a hypothetical well family. Impacts of various design and operational parameters on the pumping rates are analyzed.

• Water for future
• /
• v.29 no.1
• /
• pp.213-220
• /
• 1996

This paper presents an experimental study on the discharge head of Cherepnov water lifter that was continuously operated with the aid of the siphon. The energy used by the Cherepnov water lifter is derived from the potential energy ofthe water itself. The lifter consists of three interconnected tanks and five pipes, one of which is open and two others are hermetically sealed. The effects of varying operating parameters such as the tank and pipe size, the ratio between head of discharge and drop height were analyzed. As a result, factors that can maximize the efficiency and increase the average delivery rate were indentified. When the ratio between head of discharge and drop height is about 0.5, the efficiency of Cherepnov water lifter is maximized. In order to design the efficient Cherepnov water lifter, the discharge head of the Cherepnov water lifter should be assigned to be twice as much as the drop height. The effect of tank size on the efficiency is less than 5%, while the effect of the pipe size is not negligible. The larger the pipe size is, the more the efficiency increases.

• 보건세계
• /
• v.41 no.4 s.452
• /
• pp.20-23
• /
• 1994

• Fire Science and Engineering
• /
• v.33 no.3
• /
• pp.56-62
• /
• 2019

This study examined effects of the operating characteristics of a pump according to the rotational speed of a pump and the change in flow rate when a centrifugal pump operates under the following conditions: regulated flow rate, head, rotational speed, and specific speed of 0.7 m/min, 8 m, 1750 rpm, an 182 (m, ㎥/min, rpm), respectively. The pump in the experiment did not have a guide vane and was connected directly to the rim, so that the rotational speed of the volute pump in a spiral or volute casing increased by 100 rpm from 1350 to 1750 rpm. The result of the relationship between the H-Q, L-Q, and 𝜂-Q characteristics and the dimensionless performance characteristics, such as the head coefficient, power coefficient and efficiency were studied. The change in pump performance could be estimated depending on the increase in the number of revolutions. The maximum efficiency of the pump was 52% with 1450 rpm, 0.165 ㎥/min flux, and 4.73 m of lift. The efficiency reached 50% with a maximum of 1750 rpm, 0.183 ㎥/min of flux, and 6.72 m of lift. The efficiency curve on the performance characteristics of the lift versus flux curve became oval not a curve from a quadratic equation that passes through the starting point according to the similarity law of the pump. Finally, when the flux coefficient increased, the power coefficient increased and the lift coefficient decreased. When the flux coefficient was 0.08, the maximum efficiency was 52%. Therefore, the change in flux affects the driving characteristics.

• The Science & Technology
• /
• v.30 no.3 s.334
• /
• pp.88-89
• /
• 1997

(주)유양정보통신은 지난 1년9개월동안 총 25억의 연구개발비와 27명의 개발인력을 투입하여 광역삐삐 내장형 시티폰(CT-2플러스)을 개발해 유망한 정보통신업체로 각광을 받고 있다. 작년 9월 시험통화를 거쳐 12월부터 시판된 CT-2 플러스는 현재 1만대 정도 보급되어 있으며 호출기 기능이 내장되지 않더라도 서비스가 가능한 새제품 CT-3 개발에도 박차를 가하고 있다.

• 월간산업보건
• /
• no.8 s.244
• /
• pp.32-41
• /
• 2008

• 월간산업보건
• /
• s.242
• /
• pp.32-43
• /
• 2008