• Nuclear Engineering and Technology
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• 제55권2호
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• pp.674-680
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• 2023

The brine and seawater are important and largely untapped sources of critical trace metals and elements. The coupling of selective recovery of trace metals from seawater/brine with desalination plants gives an added advantage of energy credits to desalination plants and as well as reduce the cost of desalinated water. In this paper, status review on recovery of important trace metals and other alkali metals from seawater is presented. The potential of Indian desalination plants for recovery of trace metals, based on recovery ratio of 0.35 is also highlighted. Studies carried out by the process based on adsorption using Radiation Induced Grafted (RIG) polymeric adsorbents and then fractional elutions are presented. The fouling factors due to bio fouling and dirt fouling have been estimated for various locations of interest through field trails. The pay loader in the form of compact Contactor Assembly with minimum pressure drop, for loading specially designed radiation grafted sorbent in leaflet form has been briefed, as required for plant scale facility. The typical conceptual process design details of farm assembly of project CRUDE are described.

• Bulletin of the Korean Chemical Society
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• 제35권11호
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• pp.3244-3248
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• 2014

Two ethylenediamine cobalt(II) oxalate complexes Co(ox)(en), 1 and $Co(ox)(en){\cdot}2H_2O$, 2 have been hydrothermally synthesized and characterized by single crystal X-ray diffraction, IR spectrum, TG analysis, and magnetic measurements. In 1, Co atoms are coordinated by two bis-bidentate oxalate ions in transconfiguration to form Co(ox) chains, which are further bridged by ethylenediamine molecules to produce 2D grid layers, Co(ox)(en). In 2, Co atoms are coordinated by bridging oxalate ions in cis-configuration to form Co(ox) chains, and the additional chelation of ethylenediamine to Co atoms completes 1D zigzag chain, Co(en)(ox). Two lattice water molecules stabilize the chains through hydrogen bonding. Magnetic susceptibility measurements indicate that both complexes exhibit weak antiferromagnetic coupling between cobalt(II) ions with the susceptibility maxima at 23 K for 1 and 20 K for 2, respectively. In 1 and 2, the oxalate ligands afford a much shorter and more effective pathway for the magnetic interaction between cobalt ions compared to the ethylenediamine ligands, so the magnetic behaviors of both complexes could be well described with 1D infinite magnetic chain model.

• Nuclear Engineering and Technology
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• 제48권2호
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• pp.360-367
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• 2016

A windowless spallation target can provide a neutron source and maintain neutron chain reaction for a subcritical reactor, and is a key component of China's nuclear waste transmutation of coupling accelerator and subcritical reactor. The main issue of the windowless target design is to form a stable and controllable free surface that can ensure that energy spectrum distribution is acquired for the neutron physical design when the high energy proton beam beats the lead-bismuth eutectic in the spallation target area. In this study, morphology and flow characteristics of the free surface of the windowless target were analyzed through the volume of fluid model using computational fluid dynamics simulation, and the results show that the outlet cross section size of the target is the key to form a stable and controllable free surface, as well as the outlet with an arc transition. The optimization parameter of the target design, in which the radius of outlet cross section is $60{\pm}1mm$, is verified to form a stable and controllable free surface and to reduce the formation of air bubbles. This work can function as a reference for carrying out engineering design of windowless target and for verification experiments.

• 폴리머
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• 제36권6호
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• pp.822-830
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• 2012

본 연구에서는 실리카 나노입자를 우수한 내가수분해성을 가지는 dipodal 형태의 bis[3-(trimethoxysilyl)propyl]amine(BTMA) 실란 커플링제로 표면 개질한 후, 실리카에 도입된 BTMA의 2차 아미노기인 N-H기와 마이클 부가반응이 가능한 acrylate기를 1분자당 2개씩 가지는 poly(ethylene glycol)diacrylate(PEGDA)로 표면 처리하여 acrylate기를 실리카 입자 표면에 도입하는 연구를 수행하였다. PEGDA의 몰수 및 3가지 서로 다른 분자량의 PEGDA(M.W. 258, 575, 700) 처리가 실리카 표면에 도입되는 acrylate기의 구조에 미치는 영향을 fourier transform infrared spectroscopy(FTIR), elemental analysis(EA, 원소분석) 및 고체 상태 $^{13}C$ cross-polarization magic angle spinning(CP/MAS) nuclear magnetic resonance spectroscopy(NMR)법을 사용하여 분석하였다. 액체상태의 순수 PEGDA와 순수 BTMA를 같은 몰 비로 반응시키면 PEGDA 1분자당 2개씩 존재하는 acrylate기 중 1개 acrylate기는 순수 BTMA의 N-H기와 1:1의 비율로 마이클 부가반응이 일어나 ${\beta}$-amino acid ester를 형성하고, 나머지 1개의 acrylate기는 남아서 중합반응이 가능한 단량체 합성이 가능하다. 하지만, BTMA로 개질된 실리카 입자를 PEGDA와 반응시키면, PEGDA 1분자당 2개씩 결합있는 acrylate기 대부분이 실리카 입자에 결합되어 있는 BTMA의 N-H기와 마이클 부가반응으로 ${\beta}$-amino acid ester를 형성하여, acrylate기의 C=C기 대부분이 C-C로 변화함을 확인하였다.

• Biomolecules & Therapeutics
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• 제19권1호
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• pp.90-96
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• 2011

Automated HPLC/SPE/HPLC coupling experiments using the Sepbox system allowed the rapid identification of four bioactive principles reducing the production of amyloid $\beta$-peptide ($A{\beta}$) from two South African plants, Euclea crispa subsp. crispa and Crinum macowanii. The structures of biologically active compounds isolated from the methanol extract of Euclea crispa subsp. crispa were assigned as 3-oxo-oleanolic acid (1) and natalenone (2) based on their NMR and MS data, while lycorine (3) and hamayne (4) were isolated from the dichloromethane-methanol (1:1) extract of Crinum macowanii. These compounds were shown to inhibit the production of $A{\beta}$ from HeLa cells stably expressing Swedish mutant form of amyloid precursor protein (APPsw).

• Wind and Structures
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• 제37권4호
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• pp.275-287
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• 2023

Subgrade differential settlement of high-speed railways was a pivotal issue that could increase the risk of trains operation. The risk will be further increased when trains in the subsidence zone are affected by crosswinds. In this paper, the computational fluid dynamics (CFD) model and finite element (FE) model were established, and the data transmission interface of the two models was established by fluid-solid interaction (FSI) method to form a systematic crosswind-train-track-subgrade dynamic model. The risk of high-speed train encountering crosswind in settlement area was analyzed. The results showed that the aerodynamic force of the trains increased significantly with the increase in crosswind speed. The aerodynamic force of the trains could reach 125.14 kN, significantly increasing the risk of derailment and overturning. Considering the influence of crosswind, the risk of train operation could be greatly increased. The safety indices and the wheel-rail force both increased with the increase of the wind speed. For the high-speed train running at 350 km/h, the warning value of wind speed was 10.2 m /s under the condition of subgrade settlement with wavelength of 20 m and amplitude of 15 mm.

• Korean Chemical Engineering Research
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• 제49권2호
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• pp.181-186
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• 2011

본 연구에서는 실리카 나노 입자의 표면 개질을 위해 실란 커플링제인 3-(trimethoxysilyl)propylmethacrylate(MPS) 를 사용하여 표면 개질 반응을 수행하였다. 용매의 pH, MPS의 가수 분해 반응시간, 표면 개질 반응시간 및 실리카 표면의 실라놀기(Si-OH)에 대한 MPS의 몰 비를 변화하여 각각의 반응조건이 실리카 표면개질 반응에 미치는 영향을 연구하였다. 개질반응 후 Fourier Transform Infrared Spectroscopy(FTIR), 원소분석(EA) 및 고체 상태 cross-polarization magic angle spinning(CP/MAS) Nuclear Magnetic Resonance Spectroscopy(NMR)법을 사용하여 표면이 개질된 실리카 입자들의 분석을 수행하였다. 연구 결과 용매의 pH가 4.5일 때 MPS가 단량체 형태로 실리카 표면의 실라놀기와 반응하고 이외의 pH에서는 MPS가 이량체, 삼량체 혹은 사량체의 올리고머 형태로 실리카의 실라놀기와 반응함이 우세함을 나타내었다. 가수분해반응 시간을 30분에서 90분으로 증가시키면 MPS가 올리고머 형태로 실리카 표면의 실라놀기와 반응하는 것이 우세하고, 투입한 MPS 몰 비의 증가도 MPS가 올리고머 형태로 실리카 표면의 실라놀기와 반응하는 것이 우세함을 나타내었다.

• 한국전자파학회:학술대회논문집
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• 한국전자파학회 2003년도 종합학술발표회 논문집 Vol.13 No.1
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• pp.437-441
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• 2003

The major drawback of the classical microstrip patch antennas Is their narrow band characteristic from 1% to 5%. In this paper, to improve this drawback, we designed the antenna with stacked structure having one drive patch connected with feed line and four identical radiation patches. Resonance is achieved by adjust ing coupling area between one drive patch and four identical radiation patches and changing the size of drive patch or radial ion patches. Used substrate is FR4(${\epsilon}_r$=4.6 and t=1.6mm) and designed center frequency is 2.45GHz. The designed antenna has a wide bandwidth of 380Mhz form 2.333GHz to 2.713GHz(about 15.5%) including ISM band from 2.4GHz to 2.4835GHz.

• Bulletin of the Korean Chemical Society
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• 제28권2호
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• pp.257-262
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• 2007

The efficient synthesis of a tetrasaccharide, the suitably protected form of the repeat unit, →2)-α-D-Manp-(1→2)-β-D-Manp-(1→3)-α-D-GlcpNAc-(1→6)-α-D-Manp-(1→, of the O-antigen polysaccharide of the lipopolysaccharide from E. coli O77 has been accomplished. Glycosylation reactions for the coupling of four monosaccharide building blocks of the tetrasaccharide were carried out employing the CB glycoside method, the mannosyl 4-pentenoate/PhSeOTf method, and the glycosyl trichloroacetimidate method with complete stereoselectivities in excellent yields.

• 시스템엔지니어링학술지
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• 제12권1호
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• pp.73-87
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• 2016

Combining power generation and water production by desalination is economically advantageous. Most desalination projects use fossil fuels as an energy source, and thus contribute to increased levels of greenhouse gases. Environmental concerns have spurred researchers to find new sources of energy for desalination plants. The coupling of nuclear power production with desalination is one of the best options to achieve growth with lower environmental impact. In this paper, we will per-form a sensitivity study of coupling nuclear power to various combinations of desalination technology: {1} thermal (MSF [Multi-Stage Flashing], MED [Multi-Effect Distillation], and MED-TVC [Multi-Effect Distillation with Thermal Vapour Compression]); {2} membrane RO [Reverse Osmosis]; and {3} hybrid (MSF-RO [Multi-Stage Flashing & Reverse Osmosis] and MED-RO [Multi-Effect Distillation & Reverse Osmosis]). The Korean designed reactor plant, the APR1400 will be modeled as the energy production facility. The economical evaluation will then be executed using the computer program DEEP (Desalination Economic Evaluation Program) as developed by the IAEA. The program has capabilities to model several types of nuclear and fossil power plants, nuclear and fossil heat sources, and thermal distillation and membrane desalination technologies. The output of DEEP includes levelized water and power costs, breakdowns of cost components, energy consumption, and net saleable power for any selected option. In this study, we will examine the APR1400 coupled with a desalination power plant in the Kingdom of Saudi Arabia (KSA) as a prototypical example. The KSA currently has approximately 20% of the installed worldwide capacity for seawater desalination. Utilities such as power and water are constructed and run by the government. Per state practice, economic evaluation for these utilities do not consider or apply interest or carrying cost. Therefore, in this paper the evaluation results will be based on two scenarios. The first one assumes the water utility is under direct government control and in this case the interest and discount rate will be set to zero. The second scenario will assume that the water utility is controlled by a private enterprise and in this case we will consider different values of interest and discount rates (4%, 8%, & 12%).