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합성 제올라이트를 이용한 pH에 따른 Cu와 Zn 이온의 흡착특성 (Cu and Zn Ions Adsorption Properties at Various pH with a Synthetic Zeolite)

  • 이창한
    • 한국환경과학회지
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    • 제21권7호
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    • pp.805-813
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    • 2012
  • The removal property of Cu and Zn ions by chemical precipitation and adsorption using zeolite(Z-C1) prepared from coal fly ash(CFA) were evaluated in this study. Adsorption kinetic and equilibrium mechanisms described to analyze parameters and correlation factors with Lagergen $1^{st}$ and $2^{nd}$ order model and Langmuir and Freundlich model. Analysis of adsorption kinetics data revealed that the pseudo $2^{nd}$ order kinetics mechanism was predominant. The equilibrium data in pH 3 - 5 were able to be fitted well to a Langmuir model, by which the maximum adsorption capacities($q_{max}$) were determined at 124.9 - 140.1 mg $Cu^{2+}/g$ and 153.2 - 166.9 mg $Zn^{2+}/g$, respectively. We found that Z-C1 has a potential application as absorbents in metal ion recovery with low pH.

황강 수생태계에 대한 하천 자연도 평가 연구 (Estimation for River Naturality in the Hwang River)

  • 허만규
    • 한국환경과학회지
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    • 제22권2호
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    • pp.195-203
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    • 2013
  • I investigated the river morphology and river naturality according to the environment of the Hwang River. The numbers of flexions at the upstream regions were more than those of downstream regions. The Hwang River showed very low overall diversity of the flow. Materials of river shore at low channel width were mainly boulders or gravel at the upstream regions, and the middle and downstream were silts and clay. Artificial masonry and natural materials were mixed from materials of river levees. The Hwang River was some of the natural herbaceous vegetation to riparian zones. Land utilities for floodplain were extremely overall farmland were predominant, and partly used by natural vegetation in the forest, a soccer field, some park facilities, residential, and commercial facilities. The water was width sleep / rivers beam ratio of 10 to 20%. Currently estimation for river naturality widely used in rivers were consisted of a narrow wide a variety of items and did not reflect the actual.

Recent Advances in Animal Feed Additives such as Metabolic Modifiers, Antimicrobial Agents, Probiotics, Enzymes and Highly Available Minerals - Review -

  • Wenk, C.
    • Asian-Australasian Journal of Animal Sciences
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    • 제13권1호
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    • pp.86-95
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    • 2000
  • Animal feed additives are used worldwide for many different reasons. Some help to cover the needs of essential nutrients and others to increase growth performance, feed intake and therefore optimize feed utilization. They can positively effect technological properties and product quality. The health status of animals with a high growth performance is a predominant argument in the choice of feed additives. In many countries the use of feed additives is more and more questioned by the consumers: substances such as antibiotics and $\beta$-agonists with expected high risks are banned in animal diets. Therefore, the feed industry is highly interested in valuable alternatives which could be accepted by the consumers. Probiotics, prebiotics, enzymes and highly available minerals as well as herbs can be seen as alternatives to metabolic modifiers and antibiotics.

Coupled temperature-displacement modeling to study the thermo-elastic instability in disc brakes

  • Ramkumar, E.;Mayuram, M.M.
    • Coupled systems mechanics
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    • 제1권2호
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    • pp.165-182
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    • 2012
  • Macroscopic hot spots formed due to the large thermal gradients at the surface of the disc brake rotor, make the rotor to fail or wear out early. Thermo-elastic deformation results in contact concentration, leading to the non uniform distribution of temperature making the disc susceptible to hot spot formation. The formation of one hot spot event will predispose the system to future hot spotting at the same location. This leads to the complete thermo-elastic instability in the disc brakes; multitude parameters are responsible for the thermo elastic instability. The predominant factor is the sliding velocity and above a certain sliding velocity the instability of the brake system occurs and hot spots is formed in the surface of the disc brake. Commercial finite element package ABAQUS(R) is used to find the temperature distribution and the result is validated using Rowson's analytical model. A coupled analysis methodology is evolved for the automotive disc brake from the transient thermo-elastic contact analysis. Temperature variation is studied under different sliding speeds within the operation range.

말라리아 후유증으로 초래된 피질하성 치매 1례 (A Case of Subcortical Dementia After Cerebral Malaria)

  • 정효경;이영호;정영조;김수지;박병관
    • 생물정신의학
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    • 제2권2호
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    • pp.301-305
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    • 1995
  • Subcortical dementia may occur as a complication of cerebral malaria via deep white matter demyelination with encephalitis and diffuse small vessel vasculitis. In subcortical dementia, impairment in attention and frontal executive function are predominant. Patients are often inert, indifferent, and uninterested. They appear characteristically 'slowed up' with a marked deficit in the retrieval of information. Changes in mood, personality, and social conduct are very common. We describe a case of subcortical dementia, who has definite changes in brain MRI after cerebral malaria.

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Herbs and Botanicals as Feed Additives in Monogastric Animals

  • Wenk, Caspar
    • Asian-Australasian Journal of Animal Sciences
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    • 제16권2호
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    • pp.282-289
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    • 2003
  • Animal feed additives are used worldwide for many different reasons. Some help to cover the needs of essential nutrients and others to increase growth performance, feed intake and therefore optimize feed utilization. The health status of animals with a high growth performance is a predominant argument in the choice of feed additives. The use of feed additives is more and more questioned by the consumers. Therefore, the feed industry is highly interested in valuable alternatives which could be accepted by the consumers. Probiotics, prebiotics, enzymes and highly available minerals as well as herbs can be seen as alternatives. Herbs, spices and their extracts (botanicals) have a wide range of activities. They can stimulate feed intake and endogenous secretions or have antimicrobial, coccidiostatic or anthelmintic activity. A major field of application of herbs is the protection of animals and their products against oxidation.

열전소자를 이용한 정밀 열구동기구의 설계 및 제어 (Design and control of the precision heat actuator using thermoelectric device)

  • 서장렬;김선민;이선규
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
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    • pp.395-398
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    • 1997
  • In the modem manufacturing system, to achieve the unmanned automation, the stability of accuracy is required through a long working period. The thermal deformation of precision machine is predominant in this long time stability. While grinding slender and long workpiece at cylindrical grinding machine, we support workpiece using steadies to prevent the vibration of workpiece. The thermal deformation of the machine by grinding and internal heat source cause processing errors, so the steadies for compensating the thermal deformation in real time are strongly needed. In order to compensate these thermal deformation and grinding processing errors, the device to determine the precise positioning having the stroke of 10.mu.m is necessary. This paper suggests design and make the device to determine the precise positioning using thermoelectric device, to investigate the control characteristics and presents the heat actuator will be very useful in machine tool.

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Kinetics and Mechanism of the Anilinolysis of Dibutyl Chlorothiophosphate in Acetonitrile

  • Hoque, Md. Ehtesham Ul;Lee, Hai-Whang
    • Bulletin of the Korean Chemical Society
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    • 제33권3호
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    • pp.843-847
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    • 2012
  • The nucleophilic substitution reactions of dibutyl chlorothiophosphate (4S) with substituted anilines ($XC_6H_4NH_2$) and deuterated anilines ($XC_6H_4ND_2$) are investigated kinetically in acetonitrile at $55.0^{\circ}C$. The obtained deuterium kinetic isotope effects (DKIEs;$k_H/k_D$) are primary normal ($k_H/k_D$ = 1.10-1.35). A concerted mechanism involving predominant frontside nucleophilic attack is proposed on the basis of the primary normal DKIEs and selectivity parameters. Hydrogen bonded, four-center-type transition state is proposed. The steric effects of the two ligands on the anilinolysis rates of the chlorothiophosphates are discussed. The anilinolyses of P=S systems are compared with those of their P=O counterparts on the basis of the reactivities, thio effects, selectivity parameters, and DKIEs.

웨이브릿 기반 비디오 신호의 멀티 스트림 전송 기법 (Multi-stream Delivery Method of the Video Signal based on Wavelet)

  • 강경원;류권열;권기룡;문광석;김문수
    • 대한전자공학회:학술대회논문집
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    • 대한전자공학회 2001년도 하계종합학술대회 논문집(3)
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    • pp.101-104
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    • 2001
  • Over the last few years, streaming audio and video content on Internet sites has increased at unprecedented rates. The predominant method of delivering video over the current Internet is video streaming such as SureStream or Intelligent Stream. Since each method provides the client with only one data stream from one server, it often suffers from poor qualify of pictures in the case of network link congestion. In this paper, we propose a novel method of delivering video stream based on wavelet to a client by utilizing multi-threaded parallel connections from the client to multiple servers and to provides a better way to address the scalability functionalities. The experimental results show that the video quality delivered by the proposed multithreaded stream could significantly be improved over the conventional single video stream methods.

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