We propose a novel stripping solution containing acids (HCl and HNO3), an oxidant [(NH4)2S2O8], and complexing agents (NaCl and citric acid) to remove surface passivation layers from 14K gold alloys fabricated using an investment casting process. The optimized solution employing only HCl acid is determined by varying molar fractions of HCl and HNO3 on 14K yellow gold samples. Stripping properties are also identified for red and white gold alloy samples under the optimized stripping conditions. The removal of passivation layers, weight loss, and microstructure evolution are characterized using Raman spectroscopy, a precision scale, and optical microscopy. The proposed stripping solution effectively removes passivation layers more rapidly than conventional cyanide stripping. Weight loss increases linearly for up to 5 min for all 14K gold alloys. Red gold exhibits the greatest weight loss, followed by yellow gold and white gold. The results of microstructural analysis reveal that the conformal stripping occurs according to time. These results imply that the proposed oxidative chloride stripping might replace conventional cyanide stripping.

본 논문에서는 건물, 교량 및 해양구조물에 많이 적용되는 기본적인 형상인 벽면에 부착되어 있는 사각실린더 주변의 유동에 대해, 3개의 난류모델(v2-f 모델, k-ω 모델, k-ε 모델)을 적용하여 URANS 수치해석을 각각 수행하고, 그 결과를 비교하였다. 이 유동 은 물체의 모서리에서 발생하는 칼만와(karman vortex) 때문에 본질적으로 강한 비정상성을 가지고 있으며, 물체의 후류 영역에서도 매우 복잡한 유동구조를 가지고 있다고 알려져 있다. 3개의 난류모델이 적용된 수치해석으로부터 예측되는 평균 유동장과 지배적인 유동 의 주파수를 Wang et al.(2004; 2006)의 실험결과와 비교하였다. 비교 결과, v2-f 모델이 적용된 URANS 결과가 실험결과와 가장 유사한 결과를 보여주었고, k-ω 모델도 우수한 결과를 보인 반면, k-ε 모델은 본 대상 유동에 적용하기에 부족함을 확인하였다. 따라서 강한 박리가 존재하는 유동의 해석 시에는 v2-f 모델은 좋은 선택이다. 그리고 유동의 박리 제어를 위한 연구에 활용될 것으로 기대된다.

Heteroatoms in situ-doped hierarchical porous hollow-activated carbons (HPHACs) have been prepared innovatively by pyrolyzation of setaria viridis combined with alkaline activation for the first time. The micro-morphology, pore structure, chemical compositions, and electrochemical properties are researched in detail. The obtained HPHACs are served as outstanding electrode materials in electrochemical energy storage ascribe to the particular hierarchical porous and hollow structure, and the precursor setaria viridis is advantage of eco-friendly as well as cost-effective. Electrochemical measurement results of the HPHACs electrodes exhibit not only high specific capacitance of 350 F g−1 at 0.2 A g−1, and impressive surface specific capacitance (Cs) of 49.9 μF cm−2, but also substantial rate capability of 68% retention (238 F g−1 at 10 A g−1) and good cycle stability with 99% retention over 5000 cycles at 5 A g−1 in 6 M KOH. Besides, the symmetrical supercapacitor device based on the HPHACs electrodes exhibits excellent energy density of 49.5 Wh kg−1 at power density of 175 W kg−1, but still maintains favorable energy density of 32.0 Wh kg−1 at current density of 1 A g−1 in 1-ethy-3-methylimidazolium tetrafluoroborate ( EMIMBF4) ionic liquid electrolyte, and the excellent cycle stability behaviour shows the nearly 97% ratio capacitance retention of the initial capacitance after 10,000 cycles at current density of 2 A g−1. Overall, the results indicate that HPHACs derived from setaria viridis have appealing electrochemical performances thus are promising electrode materials for supercapacitor devices and large-scale applications.

After decades of vigorous development, data mining technology has achieved fruitful theoretical and application results. As a highly applicable subject, data mining technology has penetrated into various fields of the national economy, and has aroused great attention from academia and industry. A large amount of chart data is stored in the electronic chart database, and its application is very extensive, providing a valuable decision basis for managers in all walks of life. It is of great significance to establish a complete data management mechanism based on data mining technology. The traditional data analogy extraction technology, because of the data association index and the poor ability of data association, leads to the difference between the extraction data and the target data. Therefore, the application of data mining technology on electronic chart data management is studied. Data mining technology uses rough set to obtain the basic information of electronic chart data management according to similarity function, mining electronic chart data management association rules; through the comprehensive evaluanon data system of electronic chart data management, building rule base, setting up the evaluation index of electronic chart data management, achieving the similarity evaluation of the mining results. Experimental test results: compared with the traditional data analogy extraction technology, the results obtained by data mining technology have higher similarity with the target data and meet the requirements of electronic chart data management acquisition. It can be seen that this technology is more suitable for the application of electronic chart data management

The UNCLOS regulates complex balance of rights and duties among State parties. Its text was deliberately left vague as a result of compromise between the negotiating parties. To develop the legal norms, judges and arbitrators have referred to other rules of international law through systematic integration, rules of reference, and broad applicable law. However, judicial practice has expanded subject-matter jurisdiction beyond the UNCLOS, causing antinomy between Articles 288, on jurisdiction, and 293 of UNCLOS, on applicable law. Part XV of the UNCLOS has created an invisible community that would ideally lead the UNCLOS Tribunals to develop and follow a pragmatic approach as to the limits of their subject-matter jurisdiction in order to provide for judicial coherence. When interpreting the treaty, the establishment of genuine links between disputes and substantive rules under the UNCLOS is necessary, by which other rules of international law are firmly anchored to the interpreted texts under the UNCLOS.

The aim of this paper to provide grounds for Jeju 4.3 Human Rights educational activities to students. We have 2015 Revised Social Studies Curriculum Basic Direction - Goals and Contents of Korean History - Goals of Korean History (Revised July 27, 2018). It helps students to grasp the process of pre-modern Korean history, and use it as the basis for understanding self-identity and tradition comprehensively and systematically. Through the in-depth understanding of modern and contemporary history in Korea, students develop the ability to gain insight into the historical problems of modern Korean society. Through the process of exploring and interpreting various historical materials, students develop their ability to think critically with a critical mind and identify the historical roots of the problems faced by modern Korean society and their relevance to the world, and jointly seek ways to solve problems that can be realized at the learner level.

Chlorella gloriosa (Chlorellaceae, Trebouxiophyceae) was isolated from seawater off the coast of the Dokdo Islands in Korea. An axenic culture was established using the streak-plate method on f/2 agar media supplemented with antibiotics, allowing identification of the isolate by morphological, molecular, and physiological analyses. The morphological characteristics observed by light and electron microscopy revealed typical morphologies of C. gloriosa species. The molecular phylogenetic inference drawn from the small-subunit 18S rRNA sequence verified that the microalgal strain belongs to C. gloriosa. Additionally, gas chromatography-mass spectrometry analysis showed that the isolate was rich in nutritionally important omega-3 and -6 polyunsaturated fatty acids and high-performance liquid chromatography analysis revealed that the high-value antioxidants lutein and violaxanthin were biosynthesized as accessory pigments by this microalga, with arabinose, galactose, and glucose as the major monosaccharides. Therefore, in this study, a Korean marine C. gloriosa species was discovered, characterized, and described, and subsequently added to the national culture collection.