Angle-dependent X-ray photoelectron spectroscopy (ADXPS) is used to measure end group concentration depth profiles for blends of surface active ω-fluorosilane polystyrene with nonfunctional polystyrene. The fluorine signal is in all cases enhanced at the surface, indicating surface segregation of the lower surface tension fluorosilane end groups. End group segregation is enhanced by an increase in the concentration of ω-fluorosilane polystyrene, an increase in the nonfunctional polystyrene molecular weight, or a decrease in the molecular weight of the ω-fluorosilane polystyrene. A self-consistent mean-field lattice theory is developed to model the surface structure and properties of blends containing end-functional polymers. Lattice model calculations provide estimates of concentration depth profiles as a function of the blend composition, the normalized chain lengths of the blend constituents, and the surface and bulk interaction parameters, χs and χb, respectively. Two end-functional polystyrene architectures are considered: α-functional polystyrene for which the lattice reference volume is set equal to that of the entire fluorosilane end group and α,β-functional polystyrene where the fluorosilane end group is assumed to occupy two adjacent lattice sites at the chain end. The lattice model for both architectures provides excellent representations of experimental ADXPS data over a wide range of blend compositions and constituent molecular weights. The α,β-functional polymer model is shown to be superior on two accounts: the lattice reference volume and polymer repeat unit volumes are similar, and the optimal values of χs = −2.18 and χb = 1.59, obtained by regression of this model to ADXPS data, are consistent with group contribution estimates of these parameters.
Radioactive corrosion product materials collected from the control rod drive mechanism (CRDM) housing in a pressurized water reactor (PWR, HANBIT-1 KNPP) were analyzed using an electron probe micro analyzer (EPMA). It is challenging to analyze the composition of radioactive corrosion products using an EPMA due to the rough surface shape and size, and even more so when the products are stacked in the form of small grains.The purpose of this study is to determine whether the corrosive products found inside the CRDM housing are stuck in contact with primary coolant or just oxide. In this study, not only was the surface condition of the samples very rough, but the samples that were quantitatively analyzed using a normal method had extremely low electrical conductivity using a normal method. We therefore tested a new semiquantitative analysis method using X-ray image mapping. In this technical note, we propose a method for collecting and analyzing corrosion products adsorbed in the CRDM. Reference papers on radioactive corrosion products collected from the CRDM could not be found.It is consequently difficult to argue that the method of collecting samples and performing the quantitative analysis suggested in this study is the best, but it can be said that it is an appropriate analysis method. Finally, the usefulness of the semiquantitative analysis is reviewed by verifying the analysis results of radioactive corrosion products collected from the CRDM housing in a PWR.
본 논문에서는 국방과학연구소에서 신규 건설한 천음속풍동을 소개하고 성능에 대하여 기술하였다. 천음속풍동은 인젝터구동(Injection Driven), 폐회로(Closed Circuit) 방식의 풍동으로 시험부 크기가 가로, 세로 각각 1.5m이다. 마하수는 0.3에서 1.2까지 연속적으로 변화가능하며, 노즐을 교체하여 마하수 1.4 실험이 가능하다. 풍동의 전압력(Total Pressure)을 100kPa에서 550kPa까지 변화시킬 수 있으며, 그에 따라 레이놀즈수(Reynolds Number)를 크게 변화시켜 실험을 수행할 수 있다. 풍동의 성능을 검증하기 위하여 AGARD-B 표준모형을 이용하여 6분력 공력계수 측정 실험을 수행하였으며, 그 결과를 국과연 삼중음속풍동 및 세계 여러 풍동의 실험결과와 비교 분석하였다.
To prevent the ongoing spread of the highly infectious severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), accurate and early detection based on a rapid, ultrasensitive, and highly reliable sensing method is crucially important. Here, we present a bumpy core–shell surface-enhanced Raman spectroscopy (SERS) nanoprobe-based sensing platform with single-nanoparticle (SNP)-based digital SERS analysis. The tailorable bumpy core–shell SERS nanoprobe with an internal self-assembled monolayer of 4-nitrobenzenethiol Raman reporters, synthesized using HEPES biological buffer, generates a strong, uniform, and reproducible SERS signal with an SNP-level sensitive and narrowly distributed enhancement factor (2.1 × 108 to 2.2 × 109). We also propose an SNP-based digital SERS analysis method that provides direct visualization of SNP detection at ultralow concentrations and reliable quantification over a wide range of concentrations. The bumpy core–shell SERS nanoprobe-based sensing platform with SNP-based digital SERS analysis achieves the ultrasensitive and quantitative detection of the SARS-CoV-2 spike protein with a limit of detection of 7.1 × 10–16 M over a wide dynamic range from 3.7 × 10–15 to 3.7 × 10–8 M, far outperforming the conventional enzyme-linked immunosorbent assay method for the target protein. Furthermore, it can detect mutated spike proteins from the SARS-CoV-2 variants, representing the key mutations of Alpha, Beta, Gamma, Delta, and Omicron variants. Therefore, this sensing platform can be effectively and efficiently used for the accurate and early detection of SARS-CoV-2 and be adapted for the ultrasensitive and reliable detection of other highly infectious diseases.
In this report, we tried to form a new logistic network by introducing autonomous vehicles to present ideas for effective reduction of national logistics costs. For the efficient operation of autonomous vehicles, we conducted Analytic Hierarchy Process(AHP) and selected new hubs from existing post office locations.BR The results of the analysis are summarized as follows: nine determinants were derived for optimal location selection. Highways(0.295), National Roads(0.169), Railways(0.064), Urban Size(0.179), Urban Accessibility(0.054), GRDP(0.099), Public Land Price(0.08), Interchange(0.02), Scalability(0.04). the most influential location determinant is traffic accessibility, whereas the least influential factor is site condition.BR Although there are some limitations in the realistic assumption, it was deemed that the formation of a new network using autonomous vehicles is sufficiently efficient and it gave sufficient implications for future research.
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