Among the products of the electrocatalytic reduction of carbon dioxide (CO2RR), CO is currently the most valuable product for industrial applications. However, poor stability is a significant obstacle to CO2RR. Therefore, we synthesized a series of bimetallic organic framework materials containing different ratios of tungsten to copper using a hydrothermal method and used them as precursors. The precursors were then subjected to pyrolysis at 800 °C under argon gas, and the M-N bimetallic sites were formed after 2 h. Loose porous structures favorable for electrocatalytic reactions were finally obtained. The material could operate at lower reduction potentials than existing catalysts and obtained higher Faraday efficiencies than comparable catalysts. Of these, the current density of WCu-C/N (W:Cu = 3:1) could be stabilized at 7.9 mA ‧ cm-2 and the FE of CO reached 94 % at a hydrogen electrode potential of -0.6 V (V vs. RHE). The novel materials made with a two-step process helped to improve the stability and selectivity of the electrocatalytic reduction of CO2 to CO, which will help to promote the commercial application of this technology.
High-quality diamond films have attracted extensive attentions due to their excellent optical and electrical properties. However, several issues, such as random orientation, stress accumulation, and slow growth rate, severely limit its applications. In this paper, high-quality polycrystalline diamond films with highly ordered (100) orientation were prepared by microwave plasma chemical vapor deposition. The effects of growth parameters on the microstructure, quality and residual stress of diamond films were investigated. Experimental results indicate that relatively high temperature at low methane concentration will promote the formation of (100) oriented grains with a low compressive stress. Optimized growth parameters, a methane concentration of 2% along with a pressure of 250 Torr and temperature at 1050 ℃, were used to acquire high growth rate of 7.9 μm/h and narrow full width at half maximum of Raman peak of 5.5 cm− 1 revealing a high crystal quality. It demonstrates a promising method for rapid growth of high-quality polycrystalline diamond films with (100) orientation, which is vital for improving the diamond related applications at low cost.
During nuclear waste vitrification, loss of sodium (Na) and boron (B) occurs, as these elements are highly volatile at high temperatures, which causes fluctuations in composition and consequently affects the properties of the glass products. In this study, we investigated the volatilization behaviors of Na and B from a simulated high-level waste glass as functions of heating temperature and dwelling duration. Based on the data obtained regarding the composition of Na and B and the structure of the glass, a hypothetical model was proposed to explain the volatilization behaviors of Na and B from a structural viewpoint. As the loss of Na and B during vitrification, the crystallization of the glass occurred. Thus, the crystallization behavior of the simulated waste glass upon composition deviation was studied.
With the rapid development of the global economy, transport safety and security have become the key issues in maritime transportation all over the world. In practical applications, the Automatic Identification System (AIS)-based measurement of similarities between different vessel trajectories plays an important role in improving maritime transportation, e.g., maritime navigation, maritime supervision and management. However, the received AIS datasets are usually composed of a large amount of redundant information which could significantly increase the computational complexity. To deal with this problem, a Douglas-Peucker (DP)-based calculation method is introduced in this paper to accurately compress the spatio-temporal AIS trajectories while preserving the main geometrical structures. Based on the compressed trajectories, it is able to accelerate the Dynamic Time Warping (DTW) algorithm for the measurement of similarities between different vessel trajectories. In particular, the combination of DP and DTW has the capacity of significantly reducing the computational cost and guaranteeing the accuracy of similarity measures. The experimental results have demonstrated the superior performance of the proposed method in terms of computational cost and accuracy of similarity measures.
Luxun, whose works are well-received in Japan, is regarded as a ‘national author’. In 1909, Japanese print media for the first time reported such a ‘thought warrior’ and ‘literature master’. Since then, scholars studying Luxun has made their effort to advertise Luxun. Even up to now, it is fair enough to say as an ‘advocate’ of Chinese national culture, Luxun is still boasting of his radiance, because his works are as mellow as wine, leading readers to meaningful afterthoughts. It is found both in China and Japan that language textbooks of primary and secondary school are seen as a medium to learn about Luxun. Interpreting and teaching Luxun’s works can not only render people more capable of using language, but spread literature knowledge and enrich spiritual wold. Separated by the East China Sea, Japan published the first translated work written by Luxun in 1920s and his articles in Japanese language textbooks were also translated by famous indigenous writers or translators. There are two benefits when we take a look at how many articles written by Luxun are collected into Japanese language textbooks, explore the collecting background, interpret textbooks and analyze exercises about his articles. One is that we can have a clear understanding of the popularity and acceptance of ‘Luxun Spirit’ in Japanese basic education. The other is that we can draw some important lessons for our teaching about Luxun in middle school, and the teaching and study of ‘ China-Japan comparative literature’ for Japanese major students.
톱상어과는 톱상어목에 속하며 지금까지 2속 8종이 보고되었다. 우리나라에 서식하는 톱상어과 어류는 톱상어 1종으로 알려져 있다. 톱상어과는 주둥이 양쪽에 작고 큰 이빨이 나있으며 납작하 고 긴 것이 특징이다. 톱상어의 집단구조를 알기 위해서 4개의 지역(한국, 개체수=6; 미야기현, 개체수=1; 고치현, 개체수=1; 오키나와, 개체수=8)에서 채집된 16개체를 대상으로 형태와 분자분 석을 실시하였다. 형태분석결과 3가지의 유형으로 구분되었으며, 그 중 톱상어 A 유형은 한국과 일본에 서식하며 짧은 주둥이(전장의 26.8%), 폭넓은 주둥이(주둥이 길이는 주둥이 폭의 4.5배)를 가 지며, 톱상어 모식표본과 유사한 점에서 톱상어(Pristiophorus japonicus)로 추정된다. 톱상어 B 유 형은 오키나와에 서식하며 긴 주둥이(전장의 31.7%), 폭넓은 주둥이(5.2배)를 가져 Pristiophorus sp. 1로 제안한다. 톱상어 C 유형은 오키나와에 서식하며 긴 주둥이(전장의 31.7%), 폭좁은 주둥이 (6.3배)를 가져 Pristiophorus sp. 2로 제안한다. 나아가 톱상어 A 유형과 C 유형의 mtDNA cytb 영역을 비교한 결과 2.1~2.7% 차이를 보여 형태결과를 지지해 주었다. 향후 Pristiophorus sp. 1 및 Pristiophorus sp. 2의 분류학적 위치를 구명하기 위한 추가 연구가 필요하다.
A total of 106 two month-old Nanjiang yellow goats (male were 32, female were 34 and castrated were 40) were divided into treatment group and control group to determine the growth performance. The treatment group was reared in grazing mode, experimental group was pastured with supplement feeding. The results showed that the body weight of male in experiment group was heavier by 9.82%(P<0.05), 11.87%(P<0.01), 16.91%(P<0.01) and 23.99%(P<0.05) than that in control group in 3,4,5 and 6 month-age. The body weight of female in experimental group was heavier by 11.54%(P<0.05), 13.79%(P<0.01), 17.47%(P<0.01) and 21.15%(P<0.01) than that in control group in 3,4,5 and 6 month-old. The body weight of castrator in experimental group was heavier by 1.58%, 1.99%, 13.08%(P<0.01) and 15.76%(P<0.01) than that in control group in 3,4,5 and 6 month-age. The daily increasing weight and body measurements of experimental group is improved more than control group, especially in 6 month-age.
Laser additive direct deposition of metals is a new rapid manufacturing technology, which combines with computer aided design, laser cladding and rapid prototyping. The advanced technology can build fully-dense metal components directly from CAD files with neither mould nor tool. Based on the theory of this technology, a promising rapid manufacturing system called "Laser Metal Deposition Shaping (LMDS)" is being developed significantly. The microstructure and mechanical properties of the LMDS-formed samples are tested and analyzed synthetically. As a result, significant processing flexibility with the LMDS system over conventional processing capabilities is recognized, with potentially lower production cost, higher quality components, and shorter lead time.
Modified compact combline bandpass filters are proposed based on the miniaturized quarter-wave transmission line which is composed of the parallel coupled line and lumped capacitors. The electrical length of the parallel coupled line in a resonator, which determines the size of combline bandpass filters, is just 5˚ or 7˚, resulting in a compact circuit area. The designed combline bandpass filter also has a wide upper stopband by suppressing the spurious passbands, not moving. Measured results of two fabricated filters centered at 400MHz show good agreement with the theoretical predications.