Herein, a facile bottom–up approach for producing nitrogen-doped carbon quantum dots (N-CQDs) was carried out by the hydrothermal treatment of microcrystalline cellulose, in the presence of different nitrogen sources (blank/urea/ammonia water/ethanediamine(EDA)/Hexamethylenetetramine). The result showed that the fluorescence intensity and quantum yields (QYs) of N-CQDs with different nitrogen sources are all higher than that without nitrogen source. Compared with the other three nitrogen sources, N-CQDs prepared by EDA not only have the highest fluorescence intensity but also the largest QYs of 51.39%. Therefore, EDA was chosen as the nitrogen source to prepare N-CQDs. The obtained N-CQDs are uniform spherical particles with a diameter of 2.76 nm. The N-CQDs also exhibit excitation-dependent and long-wave emission properties. The emission range of N-CQDs is 470–540 nm. Moreover, N-CQDs as fluorescent agents successfully acted on purple LEDs (λem = 365 nm) to achieve white LEDs light emission. At the same time, a fluorescent thin layer chromatography plate was successfully prepared using N-CQDs, silica gel G and Sodium carboxymethylcellulose as raw materials. The separation trajectory of mixed sample of Sudan red III and kerosene on the fluorescent TLC plate is obviously clearer than that of the TLC plate.
Porous basalt aggregate is commonly used in roadbed engineering, but its application in concrete has rarely been studied. This paper studies the application of porous basalt in concrete. Porous basalt aggregate is assessed for its effects on mechanical strength and durability of prepared C50 concrete; because it has a hole structure, porous basalt aggregate is known for its porosity, and porous basalt aggregates can be made full of water through changing the content of saturated basalt; after full-water condition is achieved in porous basalt aggregate mixture of C50 concrete, we discuss its mechanical properties and durability. The effects of C50 concrete prepared with basalt aggregate on the compressive strength, water absorption, and electric flux of concrete specimens of different ages were studied through experiments, and the effects of different replacement rates of saturated porous basalt aggregate on the properties of concrete were also studied. The results show that porous basalt aggregate can be prepared as C50 concrete. For early saturated porous basalt aggregate concrete, its compressive strength decreases with the increase of the replacement rate of saturated aggregate; this occurs up to concrete curing at 28 d, when the replacement rate of saturated basalt aggregate is greater than or equal to 40 %. The compressive strength of concrete increases with the increase of the replacement rate of saturated aggregate. The 28 d electric flux decreases with the increase of the replacement rate of saturated aggregate, indicating that saturated porous basalt aggregate can improve the chloride ion permeability resistance of concrete in later stages.
공상과학소설(Science-Fiction; 이후 Sci-Fi로 표기)은 미래 세계에 대한 인간의 판타지를 표현하는 장르다. 이는 TV 쇼, 영화, 게임 분야에서 항상 뜨거운 주제였다. Sci-Fi 영화와 Sci-Fi 게임은 대부분 상위권에 오르고 있다. 하지만, 학계에서는 주로 Sci-Fi 영화에서 대한 논의에 더 집중하는 경향이 있다. 예를 들어, <Research on Color Modes of Well-known Contemporary Films(2020)>에 따르면, 최근 몇 년 동안 할리우드 Sci-Fi 영화의 주류 색상은 빨간색과 파란색에서 주황색, 노란색, 파란색, 녹색으로 바뀌었다고 분석하고 있다. 또한, Sci-Fi 영화와 관련된 질적 연구와 연구의 많은 성과가 있었다. 그러나 Sci-Fi 게임의 색조 경향에 대한 연구와 연구 는 매우 부족한 상황이다. 이에 본 논문은 Adams Roberts의 Sci-Fi 소설의 7가지 요소를 사용 한다. 이러한 7 가지 요소에 대한 Metacritic 점수가 사례 선택의 표준으로 사용되었다. 본 연구의 분석 대상으로는<HALO 3>, <Death Stranding>, <Cyberpunk 2077> 등 우수 PC게임 3종이 선정하였다. 또한, 데이터 분석은 NCS 색상 시스템을 기반으로 수행되어 Sci-Fi 게임의 색조 유사성에 대해 논의한다. 마지막으로, 우수한 게임의 색상 적 용에 대한 주요 성향을 결론짓고 요약함으로써, 본 연구는 Sci-Fi 게임의 색상 생산에 대한 몇 가지 이론적 참 조와 기초 데이터를 제공하고자 한다.
This work using first-principles theory proposed PdN3- doped CNT ( PdN3-CNT) as a potential gas sensor for detection of NO, NO2 and O3 in the air insulated equipment, to evaluate its operation status. Results indicate that the PdN3- CNT behaves chemisorption upon three gas species, with adsorption energy (Ead) of − 2.15, − 1.91 and − 1.96 eV, and charge-transfer (QT) of − 0.141, − 0.325 and − 0.419 e, respectively. The band structure (BS) and density of state (DOS) analysis reveal that the gas adsorptions cause remarkable deformations in the electronic property of the PdN3- CNT, leading to the increase of the bandgap for the gas adsorbed systems and verifying the strong binding force of the bonded atoms from the orbital DOS. Combined with the results by frontier molecular orbital theory, we presume that PdN3- CNT is a promising sensing material to be explored as a resistance-type gas sensor for detection of NOx with higher electrical response upon NO. It is our hope that our theoretical assumption could be further studied and realized in the following experiential research, which would be meaningful to propose novel sensing candidate in the field of electrical engineering to guarantee the safe operation of the air insulation equipment.
This study investigated the arsenide removal by using mesoporous CoFe2O4/ graphene oxide nanocomposites based on batch experiments optimized by artificial intelligence tools. These nanocomposites were prepared by immobilizing cobalt ferrite on graphene oxide and then characterized using various techniques, including small angle X-ray diffraction, high-resolution transmission electron microscopy and energy-dispersive X-ray spectroscopy. Artificial intelligence tools associated with response surface methodology were employed to optimize the conditions of the arsenide removal process. The results showed that back propagation neural network combined with genetic algorithm was suitable for the arsenide removal from aqueous solutions by the nanocomposites based on the minimum average values of absolute errors and the value of R2. The optimal values of the four variables (operating temperature, initial pH, initial arsenide concentration, and contact time) were found to be 25.66 °C, 7.58, 10.78 mg/L and 46.41 min, and the predicted arsenide removal percentage was 84.78%. The verification experiment showed that the arsenide removal percentage was 86.62%, which was close to the predicted value. Three evaluation methods (gradient boosted regression trees, Garson method and analysis of variance) all demonstrated that the temperature was the most important explanatory variable for the arsenide removal. In addition, the arsenide removal process can be depicted with pseudo-second-order kinetics model and Langmuir isotherm, respectively. The thermodynamics investigation disclosed that the adsorption process was of a spontaneously endothermic nature. In summary, this study showed that ANN-GA was an efficient and feasible method in determining the optimum conditions for arsenic removal by CoFe2O4/ graphene oxide nanocomposites.
Pantala flavescens is a dominant Odonata species in the rice fields in Korea. To determine the effects of different temperatures on its larval growth and emergence, field and laboratory experiments were conducted. Larval growth was also monitored in mono-cropping and double-cropping rice fields. The growth of larvae was monitored every week by measuring the head width. In the field experiment, no difference was found in larval growth and emergence between the control temperature and +1.9°C of the control temperature. The larval growth was greater at 23°C than at 20°C laboratory temperatures, and no emergence was recorded at either temperature after eight weeks of monitoring. There was a quadratic relationship between larval growth and temperature in an incubator at five temperature regimes of 15, 20, 25, 30, and 35°C. Midseason water drainage caused the extinction of the existing individuals and newly hatched larvae dominated after re-watering in the rice fields. Larval size was greater in double-cropping fields than in mono-cropping fields in late July but the tendency was reversed in early August. The results of this study suggest that temperature warming will directly promote the larval growth of P. flavescens and indirectly influence seasonal growth via changes in water management in rice fields.
In this study, Ni nanoparticle supported by graphene oxide (GO) (Ni-GO) is successfully synthesized through hydrothermal synthesis and calcination, and Cr(VI) is extracted from aqueous solution. The morphology and structure of Ni- GO composites are characterized by scanning electron microscopy (SEM), trans mission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). High-resolution transmission electron microscopy (HRTEM) and XRD confirms the high dispersion of Ni nanoparticle after support by GO. Loading Ni on GO can obviously enhance the stability of Ni-GO composites. It can be calculated from TGA that the mass percentage of Ni is about 60.67%. The effects of initial pH and reaction time on Cr(VI) removal ability of Ni-GO are investigated. The results indicate that the removal efficiency of Cr(VI) is greater than that of bared GO. Ni-GO shows fast removal capacity for Cr(VI) (<25 min) with high removal efficiency. Dynamic experiments show that the removal process conforms to the quasi-second order model of adsorption, which indicates that the rate control step of the removal process is chemical adsorption. The removal capacity increases with the increase of temperature, indicating that the reaction of Cr(VI) on Ni-GO composites is endothermic and spontaneous. Combined with tests and characterization, the mechanism of Cr(VI) removal by rapidly adsorption on the surface of Ni-GO and reduction by Ni nanoparticle is investigated. The above results show that Ni-GO can be used as a potential remediation agent for Cr(VI)-contaminated groundwater.
Abstract Graphene, an allotrope of carbon in 2D structure, has revolutionised research, development and application in various disciplines since its successful isolation 16 years ago. The single layer of sp2-hybridised carbon atoms brings with it a string of unrivalled characteristics at a fraction of the price of its competitors, including platinum, gold and silver. More recently, there has been a growing trend in the application of graphene in catalysis, either as metal-free catalysts, composite catalysts or as catalyst supports. The unique and extraordinary properties of graphene have rendered it useful in increasing the reactivity and selectivity of some reactions. Owing to its large surface area, outstanding adsorptivity and high compatibility with various functional groups, graphene is able to provide a whole new level of possibilities and flexibilities to design and synthesise fit-for-purpose graphene-based catalysts for specific applications. This review is focussed on the progress, mechanisms and challenges of graphene application in four main reactions, i.e., oxygen reduction reaction, water splitting, water treatment and Fischer–Tropsch synthesis. This review also summarises the advantages and drawbacks of graphene over other commonly used catalysts. Given the inherent nature of graphene, coupled with its recent accelerated advancement in the synthesis and modification processes, it is anticipated that the application of graphene in catalysis will grow exponentially from its current stage of infancy.
The primary purpose of this research is to propose the solution to the current crisis of the WTO dispute settlement system focusing on Article 25 of the WTO Agreement. The Dispute Settlement Understanding is one of the significant successes of the WTO. Recent years, however, have witnessed the difficulties and challenges facing the multilateral trading system along with rising anti-globalization and trade protectionism. The Appellate Body (AB) has been experiencing an unprecedented crisis of dysfunction mainly due to the US’s boycott of appointing the new members. The WTO Members, including China, have thus proposed various reforms in response to the crisis. However, they have not touched the core demands of the US. Because of the imminent crisis that the AB is about to stop operating, China should take urgent action with other WTO members, consider launching a majority voting program, design and use alternative appeal arbitration, and combine international rules with domestic deepening reforms.
When confronted with the host states’ increasing enthusiasm of invoking the corruption defense as an arbitral strategy to frustrate foreign investors’ claims, the International Centre for Settlement of Investment Disputes (ICSID) tribunals encounter realistic difficulties in arbitration. The inherent insufficiency of anti-corruption investigative powers bestowed to ICSID tribunals highlights the importance of constructing a coordinative mechanism between the ICSID and any domestic enforcement authorities enlisted to repudiate corruption. The enacted International Criminal Judicial Assistance Law of the People’s Republic of China provides the domestic legal basis for establishing a coordinative international criminal judicial assistance mechanism between such international organizations as ICSID and China’s domestic anti-corruption enforcement authorities. Eventually, the proposed ICSID-China’s anti-corruption mechanism will help the global community fight against international investment corruption in a coordinated way, substantially enhancing any host state’s ability to confront the on-going difficulties also experienced by investment arbitral tribunals.
The oxygen-rich activated carbon (AC) was facilely developed using petroleum coke as a raw material by KOH activation under the rapid heating rate. The porosity and surface chemistry of ACs prepared under different heating rates were characterized and their adsorption properties for methylene blue (MB) were investigated. The results showed that the AC5 prepared under the heating rate of 5 °C min−1 had the highest surface area compared with the AC10, AC15 or AC20, while the AC20 prepared under the heating rate of 20 °C min−1 consisted of the highest oxygen content and most –OH functional group compares with the other ACs. These indicated that rapid heating rate was against the formation of more developed porosity, however, it was beneficial to producing more oxygen functional groups. As to MB adsorption, AC15 exhibited the maximum adsorption capacity for MB of 884 mg g−1 due to high surface area of 2803 m2 g−1 and high oxygen content of 23.27%. Moreover, despite the fact that AC20 had much lower surface area than the AC5, the AC20 showed higher MB adsorption capacity than the AC5. This was because the AC20 has the highest content of –OH, which was a positive impetus for MB adsorption. Therefore, rapid heating rate was an effective and simple approach to preparing the oxygen-rich ACs for improving the adsorption capacity of MB.
세계적인 침입해충 담배가루이 (Bemisia tabaci Gennadius)의 한국 계통과 중국 계통의 유연관계를 알아보기 위하여 2019년에 채집한 두 계통들의 biotype 분포, 살충제 반응, 바이러스 보독율을 조사하고 차이를 분석하였다. 미토콘드리아 COI 유전자 서열을 이용하여 집단 분석한 결과 국내는 모든 지역계통에서 Q biotype만 발견되었으며, 중국은 B biotype (14.3%)과 Q biotype (85.7%)이 동시에 발견되었다. 담배가루이 Q biotype의 haplotpye 구성도 중국은 모두 Q1 그룹만 관찰되었고 Q1H1 (79.8%), Q1H2 (20.2%)로 구성되어 있었으며, 한국은 Q1이 우세한 가운 데 Q2도 관찰되었으며 Q1 그룹의 구성도 Q1H1 (1.7%), Q1H2 (97.5%)로 중국과는 크게 달랐다. 15종 살충제에 대한 약제반응은 국내 계통은 일부 약제를 제외하고 대부분 약제에서 충분한 살충력 (mortality≥80%)을 보여주었으나 중국 계통은 40% 이하의 살충력을 보인 약제들이 다수 있었으며 한국보다는 높은 저항성을 갖고 있었다. 토마토 황화잎말림바이러스 (TYLCV)의 보독율은 국내 계통에서는 발견되지 않았으며 중국의 경우 0∼60% (평균 21.4%) 가 발견되었다. 따라서 한국와 중국의 담배가루이 계통 간에는 유전적 조성과 살충제 반응, 바이러스 보독율에 있어서 큰 차이를 보여주었으며 양국의 담배가루이가 서로 다른 유입 패턴을 갖고 있음을 알 수 있었다.
This paper presents a review of the research literature on overweight and obesity problem by incorporating medical, economic and marketing research perspectives to shed lights on the growing problem across all ages and socioeconomic strata. We draw upon multidisciplinary research literature to gain a better understanding of the major causes as well as proposed remedies. Some are more likely to be more successful in addressing the difficult problem. Our conclusion is that as the issues are quite complex, no one single solution will work. It probably will require all stakeholders to be involved in order to come up with a reasonable solution to address this difficult problem. More researches need to be conducted, especially research involving cross country comparison to provide greater insights since this problem has become a global problem and not just confined to the developed economies in the West.