• 제목/요약/키워드: Modern Science

검색결과 2,614건 처리시간 0.029초

Creep of stainless steel under heat flux cyclic loading (500-1000℃) with different mechanical preloads in a vacuum environment using 3D-DIC

  • Su, Yong;Pan, Zhiwei;Peng, Yongpei;Huang, Shenghong;Zhang, Qingchuan
    • Smart Structures and Systems
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    • 제24권6호
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    • pp.759-768
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    • 2019
  • In nuclear fusion reactors, the key structural component (i.e., the plasma-facing component) undergoes high heat flux cyclic loading. To ensure the safety of fusion reactors, an experimental study on the temperature-induced creep of stainless steel under heat flux cyclic loading was performed in the present work. The strains were measured using a stereo digital image correlation technique (3D-DIC). The influence of the heat haze was eliminated, owing to the use of a vacuum environment. The specimen underwent heat flux cycles ($500^{\circ}C-1000^{\circ}C$) with different mechanical preloads (0 kN, 10 kN, 30 kN, and 50 kN). The results revealed that, for a relatively large preload (for example, 50 kN), a single temperature cycle can induce a residual strain of up to $15000{\mu}{\varepsilon}$.

Hybrid Indoor Position Estimation using K-NN and MinMax

  • Subhan, Fazli;Ahmed, Shakeel;Haider, Sajjad;Saleem, Sajid;Khan, Asfandyar;Ahmed, Salman;Numan, Muhammad
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • 제13권9호
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    • pp.4408-4428
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    • 2019
  • Due to the rapid advancement in smart phones, numerous new specifications are developed for variety of applications ranging from health monitoring to navigations and tracking. The word indoor navigation means location identification, however, where GPS signals are not available, accurate indoor localization is a challenging task due to variation in the received signals which directly affect distance estimation process. This paper proposes a hybrid approach which integrates fingerprinting based K-Nearest Neighbors (K-NN) and lateration based MinMax position estimation technique. The novel idea behind this hybrid approach is to use Euclidian distance formulation for distance estimates instead of indoor radio channel modeling which is used to convert the received signal to distance estimates. Due to unpredictable behavior of the received signal, modeling indoor environment for distance estimates is a challenging task which ultimately results in distance estimation error and hence affects position estimation process. Our proposed idea is indoor position estimation technique using Bluetooth enabled smart phones which is independent of the radio channels. Experimental results conclude that, our proposed hybrid approach performs better in terms of mean error compared to Trilateration, MinMax, K-NN, and existing Hybrid approach.

Low beta superconducting cavity system design for HIAF iLinac

  • Mengxin Xu;Yuan He;Shengxue Zhang;Lubei Liu;Tiancai Jiang;Zehua Liang;Tong Liu;Yue Tao;Chunlong Li;Qitong Huang;Fengfeng Wang;Hao Guo;Feng Bai;Xianbo Xu;Shichun Huang;Xiaoli Li;Zhijun Wang;Shenghu Zhang;Jiancheng Yang;Evgeny Zaplatin
    • Nuclear Engineering and Technology
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    • 제55권7호
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    • pp.2466-2473
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    • 2023
  • A superconducting ion-Linac (iLinac), which is supposed to work as the injector in the High Intensity heavy-ion Accelerator Facility project, is under development at the Institute of Modern Physics (IMP), Chinese Academy of Sciences. The iLinac is a superconducting heavy ion linear accelerator approximately 100 meters long and contains 96 superconducting cavities in two types of 17 cyromodules. Two types of superconducting resonators (quarter-wave resonators with a frequency of 81.25 MHz and an optimal beta β = v/c = 0.07 called QWR007 and half-wave resonators with a frequency of 162.5 MHz and an optimal beta β = 0.15 called HWR015) have been investigated. The cavity design included extensive multi-parameter electromagnetic simulations and mechanical analysis, and its results are described in details. The fundamental power coupler and cavity dynamic tuner designs are also presented in this article. The prototypes are under manufacturing and expected to be ready in 2023.

Design, fabrication and test of a taper-type half-wave superconducting cavity with the optimal beta of 0.15 at IMP

  • Yue, Weiming;Zhang, Shengxue;Li, Chunlong;Jiang, Tiancai;Liu, Lubei;Wang, Ruoxu;Huang, Yulu;Tan, Teng;Guo, Hao;Zaplatin, Evgeny;Xiong, Pingran;Wu, Andong;Wang, Fengfeng;Zhang, Shenghu;Huang, Shichun;He, Yuan;Yao, Zeen;Zhao, Hongwei
    • Nuclear Engineering and Technology
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    • 제52권8호
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    • pp.1777-1783
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    • 2020
  • As a part of R&D work for the high intensity proton linac of China Accelerator Driven Sub-critical System project, a superconducting half-wave cavity with a frequency of 162.5 MHz and an optimal beta of 0.15 (HWR015) has been developed at Institute of Modern Physics (IMP), Chinese Academy of Sciences. In this paper, the design and test results will be described in detail. We introduced a new stiffening strategy for the HWR cavity, the simulation results show that the cavity has much lower frequency sensitivity coefficient (df/dp), Lorentz force detuning coefficient (KL), and can achieve more stable mechanical properties. The performance of the HWR cavity operated in cryostat will be also reported.

스마트 그리드 기술의 현대농업에의 활용방안 (Smart Grid Utilization of modern technology in agriculture)

  • 김광만
    • 대한안전경영과학회지
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    • 제14권4호
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    • pp.211-218
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    • 2012
  • In this paper, we propose a system architecture of the AMI to be applied in the modern agricultural sector. Agricultural electricity costs in South Korea is very inexpensive compared with other industries. It is expected to increase oil prices to rise over the medium to long term so the facilities must to be installed for farmers in terms of energy savings and energy costs. The research and development of plant factory which can replace the ills of modern agriculture is very active. The technologies of smart grid and plat factory are good paradigm of next generation agricultural sector. Good use of smart grid technologies, the traditional energy consumption industries, agriculture sector can be self-sufficiency industry. In this article the AMI architecture is developed and it will be applicable for modern farmers plant factory.

초등 수준 지질학 용어의 시대적 변천과 의미 탐색 (A Study on the Changes and Meanings of Geological Terminologies for Elementary School Science Level)

  • 이면우
    • 한국초등과학교육학회지:초등과학교육
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    • 제31권4호
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    • pp.424-435
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    • 2012
  • The purpose of this study was to analyze the geological terms used in the elementary school science curriculums from 1876 to present. We collected the data of geological terminologies based on what is being used in the revised 2007 national curriculum. In this study, data was divided into three periods according to political events, "The Modern Enlightenment Period (1876~1910)", "The Japanese Colonial Period (1910~1945)", and "The Current Curriculum Period (1945~present)". During the early modern enlightenment period, translated Chinese characters' terminologies by western scholars in Qing-China were used in science books. The late modern enlightenment period, we used many translated Japanese textbooks in schools, which naturally introduced the way that Japan's terminology is used. In the Japanese colonial period, Korean students had to study science subjects written in Japanese characters, so they had used Japanese terminologies of science. After the liberation of Korea from the Imperial Japan, there was an efforts to make new Korean terminologies of geology under the new current national curriculum. However, the terminologies used in Korean textbooks ended up using and borrowing the same way that the Japanese-Sino terms of science used later.

Study on the local damage of SFRC with different fraction under contact blast loading

  • Zhang, Yongliang;Zhao, Kai;Li, Yongchi;Gu, Jincai;Ye, Zhongbao;Ma, Jian
    • Computers and Concrete
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    • 제22권1호
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    • pp.63-70
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    • 2018
  • The steel fiber reinforced concrete (SFRC) shows better performance under dynamic loading than conventional concrete in virtue of its good ductility. In this paper, a series of quasi-static experiments were carried out on the SFRC with volume fractions from 0 to 6%. The compressive strength increases by 38% while the tension strength increases by 106% when the fraction is 6.0%. The contact explosion tests were also performed on the ${\Phi}40{\times}6cm$ circular SFRC slabs of different volume fractions with 20 g RDX charges placed on their surfaces. The volume of spalling pit decreases rapidly with the increase of steel fiber fraction with a decline of 80% when the fraction is 6%, which is same as the crack density. Based on the experimental results, the fitting formulae are given, which can be used to predict individually the change tendencies of the blast crater volume, the spalling pit volume and the crack density in slabs with the increase of the steel fiber fraction. The new formulae of the thickness of damage region are established, whose predictions agree well with our test results and others. This is of great practical significance for experimental investigations and engineering applications.

A Ghost-Imaging System Based on a Microfluidic Chip

  • Wang, Kaimin;Han, Xiaoxuan;Ye, Hualong;Wang, Zhaorui;Zhang, Leihong;Hu, Jiafeng;Xu, Meiyong;Xin, Xiangjun;Zhang, Dawei
    • Current Optics and Photonics
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    • 제5권2호
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    • pp.147-154
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    • 2021
  • Microfluidic chip technology is a research focus in biology, chemistry, and medicine, for example. However, microfluidic chips are rarely applied in imaging, especially in ghost imaging. Thus in this work we propose a ghost-imaging system, in which we deploy a novel microfluidic chip modulator (MCM) constructed of double-layer zigzag micro pipelines. While in traditional situations a spatial light modulator (SLM) and supporting computers are required, we can get rid of active modulation devices and computers with this proposed scheme. The corresponding simulation analysis verifies good feasibility of the scheme, which can ensure the quality of data transmission and achieve convenient, fast ghost imaging passively.

Effects of a multi-strain probiotic on growth, health, and fecal bacterial flora of neonatal dairy calves

  • Guo, Yongqing;Li, Zheng;Deng, Ming;Li, Yaokun;Liu, Guangbin;Liu, Dewu;Liu, Qihong;Liu, Qingshen;Sun, Baoli
    • Animal Bioscience
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    • 제35권2호
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    • pp.204-216
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    • 2022
  • Objective: The aim of this study was to investigate the effects of dietary supplementation with a multi-strain probiotic (MSP) product containing of Bifidobacterium animalis, Lactobacillus casei, Streptococcus faecalis, and Bacillus cerevisiae on growth, health, and fecal bacterial composition of dairy calves during the first month of life. Methods: Forty Holstein calves (24 female and 16 male) at 2 d of age were grouped by sex and date of birth then randomly assigned to 1 of 4 treatments: milk replacer supplementation with 0 g (0MSP), 2 g (2MSP), 4 g (4MSP), and 6 g (6MSP) MSP per calf per day. Results: Supplementation of MSP did not result in any significant differences in parameters of body measurements of calves during the 30 d period. As the dosage of MSP increased, the average daily gain (p = 0.025) and total dry matter intake (p = 0.020) of calves showed a linear increase. The fecal consistency index of the 2MSP, 4MSP, and 6MSP group calves were lower than that of the 0MSP group calves (p = 0.003). As the dosage of MSP increased, the concentrations of lactate dehydrogenase (p = 0.068) and aspartate aminotransferase (p = 0.081) in serum tended to decrease, whereas the concentration of total cholesterol increased quadratically (p = 0.021). The relative abundance of Dorea in feces was lower (p = 0.011) in the 2MSP, 4MSP, and 6MSP group calves than that in the 0MSP group calves. The relative abundance of Dorea (p = 0.001), Faecalibacterium (p = 0.050), and Mitsuokella (p = 0.030) decreased linearly, whereas the relative abundance of Prevotella tended to increase linearly as the dosage of MSP increased (p = 0.058). Conclusion: The MSP product can be used to reduce the diarrhea, improve the performance, and alter the composition of the fecal bacteria in neonatal dairy calves under the commercial conditions.