In the present investigation, a new electrochemical sensor based on carbon paste electrode was applied to simultaneous determine the tramadol, olanzapine and acetaminophen for the first time. The CuO/reduced graphene nanoribbons (rGNR) nanocomposites and 1-ethyl 3-methyl imidazolinium chloride as ionic liquid (IL) were employed as modifiers. The electrooxidation of these drugs at the surface of the modified electrode was evaluated using cyclic voltammetry (CV), differential pulse voltammetry (DPV), electrochemical impedance spectroscopy (EIS) and chronoamperometry. Various techniques such as scanning electron microscopy (SEM) with energy dispersive X-Ray analysis (EDX), X-ray diffraction (XRD) and fourier-transform infrared spectroscopy (FTIR), were used to validate the structure of CuO-rGNR nanocomposites. This sensor displayed a superb electro catalytic oxidation activity and good sensitivity. Under optimized conditions, the results showed the linear in the concentration range of 0.08–900 μM and detection limit (LOD) was achieved to be 0.05 μM. The suggested technique was effectively used to the determination of tramadol in pharmaceuticals and human serum samples. For the first time, the present study demonstrated the synthesis and utilization of the porous nanocomposites to make a unique and sensitive electrode and ionic liquid for electrode modification to co-measurement of these drugs.
Level measurement of liquid radwaste is essential for inventory management of treatment system. Among various methods, level measurement based on differential pressure has many advantages. First, it is possible to measure the liquid level of the system regardless of liquid type. Second, as the instrument doesn’t need to be installed near the tank, there is no need to contact the tank when managing it. Therefore, workers’ radiation dose from the system can be decreased. Finally, although it depends on the accuracy, the price of the instrument is relatively low. With these advantages, in general, liquid radwaste level in a tank is measured using differential pressure in the treatment system. Not only the advantages described above, there are some disadvantages. As the liquid in the system is waste, it is not pure but has some suspended materials. These materials can be accumulated in tanks and pipes where the liquids move to come into direct contact with pneumatic pipes that are essential in differential pressure instruments. As a result, in case of a treatment using heat source, the accumulated materials may become sludge causing interference in pneumatic pipes. And this can change the pressure which also affects the level measured. In conclusion, in case of liquid storage tanks in which the situation cannot be checked, the proficiency of an operator becomes important.
Molten Salt Reactor (MSR) is one of Generation-IV nuclear reactors that uses molten salts as a fuel and coolant in liquid forms at high temperatures. The advantages of MSR, such as safety, economic feasibility, and scalability, are attributed from the fact that the molten salt fuel in a liquid state is chemically stable and has excellent thermo-physical properties. MSR combines the fuel and coolant by dissolving the actinides (U, Th, TRU, etc.) in the molten salt coolant, eliminating the possibility of a core meltdown accident due to loss of coolant (LOCA). Even if the molten salt fuel leaks, the radioactive fission products dissolved in the molten salt will solidify with the fuel salt at room temperature, preventing potential leakage to the outside. MSR was first demonstrated at ORNL starting with the Aircraft Reactor Experiment (ARE) in 1954 and was extended to the 7.4 MWth MSRE developed in 1964 and operated for 5 years. Recently, various start-ups, including TerraPower, Terrestrial Energy, Moltex Energy, and Seaborg, have been conducting research and development on various types of MSR, particularly focusing on its inherent safety and simplicity. While in the past, fluoride-based molten salt fuels were used for thermal neutron reactors, recently, a chlorine-based molten salt fuel with a relatively high solubility for actinides and advantageous for the transmutation of spent nuclear fuel and online reprocessing has been developing for fast neutron spectrum MSRs. This paper describes the development status of the process and equipment for producing highpurity UCl3, a fuel material for the chlorine-based molten salt fuel, and the development status of the gas fission product capturing technologies to remove the gaseous fission products generated during MSR operation. In addition, the results of the corrosion property evaluation of structural materials using a natural circulation molten salt loop will also be included.
Gamma-ray spectroscopy, which is an appropriate method to identify and quantify radionuclides, is widely utilized in radiological leakage monitoring of nuclear facilities, assay of radioactive wastes, and decontamination evaluation of post-processing such as decommissioning and remediation. For example, in the post-processing, it is conducted to verify the radioactivity level of the site before and after the work and decide to recycle or dispose the generated waste. For an accurate evaluation of gamma-ray emitting radionuclides, the measurement should be carried out near the region of interest on site, or a sample analysis should be performed in the laboratory. However, the region is inaccessible due to the safety-critical nature of nuclear facilities, and excessive radiation exposure to workers could be caused. In addition, in the case of subjects that may be contaminated inside such as pipe structures generated during decommissioning, surveying is usually done over the outside of them only, so the effectiveness of the result is limited. Thus, there is a need to develop a radiation measurement system that can be available in narrow space and can sense remotely with excellent performance. A liquid light guide (LLG), unlike typical optical fiber, is a light guide which has a liquid core. It has superior light transmissivity than any optical fiber and can be manufactured with a larger diameter. Additionally, it can deliver light with much greater intensity with very low attenuation along the length because there is no packing fraction and it has very high radiation resistant characteristics. Especially, thanks to the good transmissivity in UV-VIS wavelength, the LLG can well transmit the scintillation light signals from scintillators that have relatively short emission wavelengths, such as LaBr3:Ce and CeBr3. In this study, we developed a radiation sensor system based on a LLG for remote gamma-ray spectroscopy. We fabricated a radiation sensor with LaBr3:Ce scintillator and LLG, and acquired energy spectra of Cs-137 and Co-60 remotely. Furthermore, the results of gamma-ray spectroscopy using different lengths of LLG were compared with those obtained without LLG. Energy resolutions were estimated as 7.67%, 4.90%, and 4.81% at 662, 1,173, and 1,332 keV, respectively for 1 m long LLG, which shows similar values of a general NaI(Tl) scintillator. With 3 m long LLG, the energy resolutions were 7.92%, 5.48%, and 5.07% for 662, 1,173, and 1,332 keV gamma-rays, respectively.
이온성 액체 기반 혼합 멤브레인(MMM)은 이산화탄소 분리 매체로써 다양한 종류의 이온성 액체와 무기성 필러 폴리머에 의해 만들어진다. 이온성 액체와 무기성 필러의 강한 상호작용은 이산화탄소의 금속 유기체의 프레임워크 내 친화 력, 선택성, 흡착성을 높여 분리성능을 향상시킨다. 또, 이온성 액체에 의해 혼합 매트릭스 멤브레인의 구조적 특성이 조절되 어 이산화탄소 투과성과 선택성을 향상시킨다. 이 리뷰에서는 이산화탄소 분리를 위한 고분자 막에서의 이온성 액체(IL)와 금속 유기체 프레임워크(MOF)의 다양한 조합에 대한 연구가 논의될 것이다.
유기 양이온과 유기/무기 음이온을 포함하고 있는 이온성 액체는 저온 용융 염의 종류이며 이산화탄소 분리 기능 에 대한 잠재력을 갖고 있다. 지구 온난화와 기후 변화의 문제점을 극복하기 위해 이온성 액체를 기반으로 한 막을 개발하여 연도가스에서 이산화탄소를 걸러내는 연구가 활발히 진행되고 있다. 본 리뷰에서는 홀로 설 수 있는 중합 이온성 액체(PIL), 이온성 액체와 이온성 액체 복합 막의 혼합의 기술이 논의될 것이다. 새로운 이온성 액체의 모노머 도입, 그리고 중합 이온성 액체 막과 복합 막의 미세구조변형은 막의 기계적 특성을 향상시켜 가스투과율과 선택도를 크게 향상 시키는데 시용되어 왔 다. 이온성 액체 모너머의 양이온과 음이온의 다양한 변형은 막의 가스 분리성에 큰 영향이 있다.
고분자를 기반으로 하는 고체 전해질은 수퍼커패시터, 배터리, 센서, 액추에이터 등 다양한 전기화학 소자에 응용이 가능한 소재로써, 기존 고분자 전해질의 낮은 이온전도도를 향상시키기 위해서 다양한 이온성 액체 기반의 고체 전해질에 관한 연구가 활발히 진행 중에 있다. 이온성 액체의 높은 전기적 특성 및 전기화학적, 열적 안정성과 고분자의 우수한 기계적인 강도를 활용한 젤 상태의 고체 전해질인 이온젤은 차세대 웨어러블 및 플렉시블 전자소자에 응용되어 연구되고 있다. 따라서 본 연구에서는 이러한 이온성 액체와 고분자 기반의 고체 전해질을 제조하고 특성을 분석하여 탄소나노복합체 기반의 전극 에 적용하여 다양한 전자소자에 응용이 가능한 이온전도도 및 안정성이 향상된 이온성 액체 기반의 고체 전해질을 개발하고자 한다. 제조된 고체전해질은 전기화학적 임피던스법을 이용하여 이온 전도도를 측정 하여 보았으며 이온성 액체를 첨가하여 제조한 고체전해질의 이온 전도도가 1.26 x 10-1 S/cm 로 확인 되었다. 또한 제조된 고체 전해질을 이용하여 전고체형 수퍼커패시터를 제조하여 전기화학적 특성을 비교 하여 보았으며, 수퍼커패시터의 전기화학적 특성 역시 이온성 액체를 첨가하여 제조된 고체 전해질을 사 용하였을 때 향상된 전기화학적 특성을 나타내었다.
Abstract We demonstrate convenient alignment technologies using imprinting lithography with sol-gel process. The aligned nano pattern is fabricated on a silicon wafer by laser interference lithography. For conformal imprinting process, aligned nano pattern was transferred onto the polydimethylsiloxane (PDMS). Using a PDMS sheet with aligned nano pattern, aligned nano pattern was created onto the sol-gel driven hafnium zinc oxide by imprinting lithography. The process was conducted at annealing temperatures of 150 °C. The obtained pattern on the HfZnO film acted as a guide for aligning liquid crystal (LC) molecules. The geometric restriction induced by aligned pattern leads to LC alignment along to the aligned nano pattern. The combination of imprint lithography and solution-processed inorganic materials proved good alternative of LC alignment technique.
본 논문에서는 SBS-g-POEM 블록-그래프트 공중합체, 이온성 액체(EMIMTFSI) 및 ZIF-8 나노 입자를 사용하여 CO2/N2 기체를 분리하기 위한 혼합 매질 분리막(MMMs)을 개발하였다. SBS-g-POEM은 낮은 비용이 드는 자유 라디칼 중합 법을 통해 합성된 유연한 블록-그래프트 공중합체이다. EMIMTFSI는 SBS-g-POEM 매트릭스에 용해시켰으며, 합성된 ZIF-8 나노 입자들 역시 공중합체의 매트릭스에 분산시켰다. 제조된 시료들의 특성은 푸리에 변환 적외 분광법(FT-IR), 시차 주사 열량계(DSC), 주사 전자 현미경(SEM), X선 회절 분석(XRD)을 통해 확인하였으며, 분석 결과 각 성분들은 서로 간의 좋은 혼화성을 나타내었다. 기체 분리 성능은 time-lag measurements를 통해 확인되었으며, 537.0 barrer의 CO2 투과도와 15.2의 CO2/N2 선택도를 나타내었다. 이를 통해 첨가된 EMIMTFSI와 ZIF-8 나노 입자는 CO2/N2 선택도를 크게 희생시키지 않고 기체 투과 도를 두 배 이상 향상시키는 것으로 확인되었다.
광중합 방법을 이용하여 고리화 중합이 가능한 디알릴 기를 포함하는 액정 단량체를 합성하였고 이를 이용하여 액정의 상전이 특성 및 배향특성과 중합거동에 대하여 연구하였다. 액정단량체는 2-methyl-1,4-phenylene 기를 중 심구조로 하며 양 말단에 고리화 중합이 가능한 1,6-heptadienyl 기를 포함한다. 합성된 액정단량체를 1H-NMR로 구 조 분석을 하였으며 DSC와 POM을 이용하여 액정단량체의 상전이를 관찰하였다. 그 결과 합성된 합성된 액정단량체는 가열시에는 액정상이 관찰되지 않고 약 52 oC에서 등방성 액체로 녹았으며, 냉각시에는 49.1 oC에서 –9.5 oC 사이에서 전형적이 네마틱 상을 보이고 그 이하에서는 결정성을 나타내는 enatiotropic 상전이를 나타내었다. 합성된 액정 단량체는 광개시제를 포함하는 중합용액으로 제조하여 코팅 후 광조사를 통해 고리화 중합을 진행하였으며, 그 결과 고분자필름을 제조하는 데에는 성공하였으나 중합과정 중 배향이 파괴되어 광학필름으로 사용할 수는 없었다.
There have been continuous research activities towards the designing of various separation technologies for the sequestration of CO2. Organic polymer membranes pay a great attention for its eco-friendliness, simple operation and energy-saving. Polymer membranes such as polyimides, polyethers, TRs and PIMs are well known for their high permeability and excellent mechanical, chemical, and thermal properties. However, the foremost challenge for these polymeric membrane materials is their enhanced selectivity to CO2 without sacrificing permeability. The selectivity problems would be overcome by ionic liquids (ILs), which lead to a considerable attention on RTILs-based sequestrations for CO2/N2 and CO2/CH4 separations. The current research trends based on RTIL polymer membranes, together with our original concept of applying RTIL to various polymeric structures will be presented.