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CALCINATION OF ALUMINUM CHLORIDE HEXAHYDRATE (ACH) FOR ALUMINA PRODUCTION: IMPLICATIONS FOR ALUMINA EXTRACTION FROM ALUMINUM RICH FLY ASH (ARFA)

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ARChiVES OF METALLURGY AND MATERIALS 2018年第1期63卷 235-240页

作者： Zhao, L. Natl Inst Clean & LOW Carbon Energy Xiaotangshan Future Sci & Technol City POB 001 Shenhua Nice Beijing 102211 Peoples R China

Alumina rich fly ash (ARFA) has been regarded as the alternative to bauxite in china. Hydrochloric acid process could be favored for alumina extraction, necessitating calcination of aluminum chloride hexahydate (ACH). In this work, the TGA/DSC results of ACH were used to suggest calcination procedures. Two-step calcinations of 200-1000 degrees C and 350-1000 degrees C did not increase the surface area of alumina, by comparison with one step 1000 degrees C calcination, and a slow heating rate could improve the surface area. Calcination temperature was increased from 950 to 1250 degrees C in a step of 50 degrees C, and XRD, XRF, BET and gas pycnometer were used to characterize the alumina from calcinated ACH. Consistent results were obtained by these different techniques, and two groups of impurities were identified and related to alumina purity and surface area. By comparison with clays, it was suggested to remove impurities such as MgO, Na2O, K2O, P2O5 and SO3 in hydrochloric acid leaching of ARFA.

关键词： calcination aluminum chloride hexahydrate alumina rich fly ash acid leaching

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Focal infrared neural stimulation with high-field functional MRI: A rapid way to map mesoscale brain connectomes

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SCIENCE ADVANCES 2019年第4期5卷 eaau7046页

作者： Xu, Augix Guohua Qian, Meizhen Tian, Feiyan Xu, Bin Friedman, Robert M. Wang, Jianbao Song, Xuemei Sun, Yi Chernov, Mykyta M. Cayce, Jonathan M. Jansen, E. Duco Mahadevan-Jansen, Anita Zhang, Xiaotong Chen, Gang Roe, Anna Wang Zhejiang Univ Interdisciplinary Inst Neurosci & Technol Qiushi Acad Adv Studies Affiliated Hosp 2Sch Med Hangzhou 310029 Peoples R China Zhejiang Univ Minist Educ Key Lab Biomed Engn Hangzhou 310029 Peoples R China Vanderbilt Univ Dept Psychol Nashville TN 37203 USA Oregon Hlth & Sci Univ Oregon Natl Primate Res Ctr Div Neurosci Beaverton OR 97239 USA Siemens Healthcare MR Collaborat Northeast Asia Shanghai 200001 Peoples R China Vanderbilt Univ Dept Biomed Engn Nashville TN 37203 USA Vanderbilt Univ Biophoton Ctr Nashville TN 37232 USA Vanderbilt Univ Med Ctr Nashville TN 37232 USA

We have developed a way to map brain-wide networks using focal pulsed infrared neural stimulation in ultrahigh-field magnetic resonance imaging (MRI). The patterns of connections revealed are similar to those of connections previously mapped with anatomical tract tracing methods. These include connections between cortex and subcortical locations and long-range cortico-cortical connections. Studies of local cortical connections reveal columnar-sized laminar activation, consistent with feed-forward and feedback projection signatures. This method is broadly applicable and can be applied to multiple areas of the brain in different species and across different MRI platforms. Systematic point-by-point application of this method may lead to fundamental advances in our understanding of brain connectomes.

关键词： Magnetic resonance imaging

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A New Method to Estimate SNR of Remote Sensing Imagery

A New Method to Estimate SNR of Remote Sensing Imagery

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Annual Conference of the Chinese-Society-for-Optical-Engineering (CSOE) on Applied Optics and Photonics china (AOPC) - Optical Sensing and Imaging technology and Applications

作者： Zhu, Bo Li, Chuanrong Wang, Xinhong Wang, Chaoliang Chinese Acad Sci Acad Optoelect Key Lab Quantitat Remote Sensing Informat Technol Beijing 100094 Peoples R China

ISBN: (数字)9781510614062

ISBN: (纸本)9781510614062;9781510614055

The signal-to-noise ratio (SNR) of a remote sensing image is one of the most important indicators to evaluate the quality of the image, and also can reflect the SNR performance of a remote sensing payload to a great extent. Meanwhile, the SNR determines the information precision of a remote sensing image by which researchers could use the spectral characteristics to identify the surface features. Optical remote sensing images are usually contaminated by Gaussian white noise. Surface features often interfere with each other when imaging, which increases the difficulty of SNR evaluation. For heterogeneous region, the interference between different features is stronger and could not be removed easily. For homogeneous region, same features present the same or similar characteristics, showing as similar digital number (DN) values, so the interference between same features could be removed in some way. One of the ways to remove the interference between same features is to do subtraction operation between the adjacent row DNs or column DNs in homogeneous region. And the residuals, due to subtraction, are more indicative to the noises. This paper presents a novel method for SNR estimation of optical remote sensing images. Firstly, calculating the column residuals between the same features in homogeneous region. Secondly, doing subtraction operation to calculate the row residuals between the same features in homogeneous region. Thirdly, integrating the column and row residuals to evaluate the SNR. In this paper, the new method and a traditional typical method are used to estimate the SNRs of measured images. By analyzing the results of the two methods, we can find the new one is more stable and accurate. This method provides a new way to evaluate the SNR performance of optical remote sensing payload onboard.

关键词： SNR Signal-to-Noise Ratio SNR Estimation Integrating SNR Column Residuals Row Residuals

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VAIL: A victim-aware cache policy for improving lifetime of hybrid memory 9

VAIL: A victim-aware cache policy for improving lifetime of ...

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9th International Workshop on programming Models and Applications for Multicores and Manycores, PMAM 2018

作者： Jia, Youchuang Zhou, Fang Gao, Xiang Wu, Song Jin, Hai Liao, Xiaofei Yuan, Pingpeng Services Computing Technology and System Lab Cluster and Grid Computing Lab Huazhong University of Science and Technology Wuhan430074 China

ISBN: (纸本)9781450356459

Nowadays emerging Non-Volatile Memory (NVM) technologies are introduced to remedy the shortages of the current DRAM-based memory system. However, NVM has limited write endurance, which would severely restrict the performance of memory system. In order to relieve above limitation, we proposed a victim-aware cache policy (VAIL), based on DRAM and NVM hybrid memory system. VAIL took the eviction locality of victims from the DRAM cache into consideration, to reduce writebacks to NVM and improve DRAM hit ratio at the same time. Our evaluation shows that VAIL could reduce 17.2% writebacks to NVM with single-core workloads, 22% writebacks to NVM with multi-core workloads and improve the DRAM hit ratio of the hybrid memory system. © 2018 Association for Computing Machinery.

关键词： Dynamic random access storage

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A Systematic Approach for Collision Risk Analysis based on AIS Data

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JOURNAL OF NAVIGATION 2017年第5期70卷 1117-1132页

作者： Zhang, Weibin Kopca, Cole Tang, Jinjun Ma, Dongfang Wang, Yinhai Nanjing Univ Sci & Technol Sch Elect & Opt Engn Nanjing 210094 Jiangsu Peoples R China Univ Washington Dept Civil & Environm Engn Smart Transportat Applicat & Res Lab Seattle WA 98195 USA Cent S Univ Sch Traff & Transportat Engn Changsha 410075 Hunan Peoples R China Zhejiang Univ Ocean Coll Zhoushan 316021 Zhejiang Peoples R China

Ship collision risk is an important aspect of ship navigation safety. A systematic method to assess collision risk by monitoring parameter states continually is necessary and has proven effective. Another important factor in risk assessment is ship size, but the effect of the size of ship pairs has not been considered properly in many previous studies. This research utilises a systematic perspective to study collision risk of near-misses in ship-ship encounters. This fills a secondary research gap where previous risk assessments only investigated near-misses from the perspective of a single vessel. Following this proposed approach, ship pair encounter states can be continually tracked. Ultimately, a method of improved Vessel Collision Risk Operator (VCRO) to merge risk assessments of both ships is proposed through integration of near-miss collision risks in a systematic way, which overcomes the disadvantages of prior VCROs that only consider the maximum value, from which it is difficult to track and judge the risk trend. Utilising a case study, the effectiveness of the proposed method is validated through analysis of ship encounters, with ships of different sizes in the Baltic Sea.

关键词： Ship-ship collision AIS data Traffic conflict Maritime safety Risk Analysis

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A Fast Microwave Correlated Imaging Method Based on Strip Division in Large Scenes 15

A Fast Microwave Correlated Imaging Method Based on Strip Di...

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15th IEEE International Meeting on Future of Electron Devices, Kansai (IMFEDK)

作者： Guo, Yuanyue Deng, Jie Wang, Dongjin Univ Sci & Technol China Chinese Acad Sci Key Lab Electromagnet Space Informat Hefei Anhui Peoples R China

ISBN: (纸本)9781509039920

A fast correlated imaging method based on strip division in large scenes is proposed. By transmitting narrow-pulse random signals synchronously from random radiation radar array, the whole imaging area is divided into multiple strips in range direction, then correlated imaging model in strip mode is established, which reduces the scale of its imaging matrix equation greatly;By multi-strip stitching, a whole correlated imaging in a large scene can be achieved;Numerical simulations validate its effectiveness in reducing its imaging time dramatically meanwhile improving its image quality.

关键词： fast correlated imaging large Scene narrow-pulse random radiation radar array imging strip division

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Study of closed-loop high-resolution sigma-delta for a MEMS accelerometer

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IEICE ELECTRONICS EXPRESS 2018年第2期15卷

作者： Sun, Zhiyuan Yina, Liang Li, Xiangyu Fu, Qiang Liu, Xiaowei Inst Engn Mech Key Lab Earthquake Engn & Engn Vibrat Harbin Heilongjiang Peoples R China MEMS Ctr Key Lab Microsyst & Microstruct Mfg Harbin Heilongjiang Peoples R China

In this paper, a high-resolution Sigma-Delta (Sigma Delta) modulator in a standard 0.5 mu m CMOS technology for a MEMS accelerometer is presented. The digital output is attained by the interface circuit based on a low-noise front-end charge-amplifier and a back-end forth-order Sigma-Delta modulator. The low-noise front-end detection circuit is proposed with correlated double sampling (CDS) technique to eliminate the 1/f noise and offset of operational amplifier. The capacitance compensation array is used for rejecting the sensor element mechanical offset. The lead compensator circuit is to ensure the stability of the high-order closed-loop system. The interface is fabricated in a standard 0.5 mu m CMOS process and the active circuit area is about 8 mm(2). The MEMS accelerometer system consumes 25 mW from a single 7 V supply at a sampling frequency of 250 kHz. The Sigma Delta modulator can achieve an effective number of bits 20.30 bits and an average noise floor in low-frequency range of 140 dB.

关键词： MEMS accelerometer interface circuit capacitance compensation array Sigma-Delta

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A 420nm Blue Diode Laser for the Potential Rubidium Optical Frequency Standard

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Chinese Physics Letters 2017年第7期34卷 118-121页

作者：张盛楠张晓刚涂建辉蒋招杰商浩森祝传文杨炜崔敬忠陈景标 State Key Laboratory of Advanced Optical Communication Systems and Networks and Institute of Quantum Electronics School of Electronics Engineering and Computer Science Peking University National Key Laboratory of Science and Technology on Vacuum Technology & Physics Lanzhou Institute of PhysicsChina Academy of Space Technology

We report a 42Ohm external cavity diode laser with an interference filter （IF） of 0.5am narrow-bandwidth and 79% high transmission, which is first used for Rb optical frequency standard. The IF and the cat-eye reflector are used for selecting wavelength and light feedback, respectively. The measured laser linewidth is 24 kHz when the diode laser is free running. Using this narrow-linewidth IF blue diode laser, we realize a compact Rb optical frequency standard without a complicated PDH system. The preliminary stability of the Rb optical frequency standard is 2 × 10^-13 at I s and decreases to 1.9 ×10^-14 at 1000s. The narrow-linewidth characteristic makes the IF blue diode laser a well suited candidate for the compact Rb optical frequency standard.

关键词： A 420nm Blue Diode Laser for the Potential Rubidium Optical Frequency Standard Rb kHz

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The dynamic landscape of gene regulation during Bombyx mori oogenesis

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BMC GENOMICS 2017年第1期18卷 1-13页

作者： Zhang, Qiang Sun, Wei Sun, Bang-Yong Xiao, Yang Zhang, Ze Chongqing Univ Sch Life Sci Lab Evolutionary & Funct Genom Chongqing 400044 Peoples R China Guangdong Acad Agr Sci Sericulture & Agrifood Res Inst Guangzhou 510640 Guangdong Peoples R China Chongqing Univ Sch Life Sci Lab Evolutionary & Funct Genom Chongqing 401331 Peoples R China

Background: Oogenesis in the domestic silkworm (Bombyx mori) is a complex process involving previtellogenesis, vitellogenesis and choriogenesis. During this process, follicles show drastic morphological and physiological changes. However, the genome-wide regulatory profiles of gene expression during oogenesis remain to be determined. Results: In this study, we obtained time-series transcriptome data and used these data to reveal the dynamic landscape of gene regulation during oogenesis. A total of 1932 genes were identified to be differentially expressed among different stages, most of which occurred during the transition from late vitellogenesis to early choriogenesis. Using weighted gene co-expression network analysis, we identified six stage-specific gene modules that correspond to multiple regulatory pathways. Strikingly, the biosynthesis pathway of the molting hormone 20-hydroxyecdysone (20E) was enriched in one of the modules. Further analysis showed that the ecdysteroid 20-hydroxylase gene (CYP314A1) of steroidgenesis genes was mainly expressed in previtellogenesis and early vitellogenesis. However, the 20E-inactivated genes, particularly the ecdysteroid 26-hydroxylase encoding gene (Cyp18a1), were highly expressed in late vitellogenesis. These distinct expression patterns between 20E synthesis and catabolism-related genes might ensure the rapid decline of the hormone titer at the transition point from vitellogenesis to choriogenesis. In addition, we compared landscapes of gene regulation between silkworm (Lepidoptera) and fruit fly (Diptera) oogeneses. Our results show that there is some consensus in the modules of gene co-expression during oogenesis in these insects. Conclusions: The data presented in this study provide new insights into the regulatory mechanisms underlying oogenesis in insects with polytrophic meroistic ovaries. The results also provide clues for further investigating the roles of epigenetic reconfiguration and circadian rhythm in insect o

关键词： Bombyx mori Oogenesis Gene regulation Ecdysteroid biosynthesis Co-expression network Transcription factors

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Effect of high temperature pretreatment on the thermal resistance properties of Pd/CeO2/Al2O3 close-coupled catalysts

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Journal of Rare Earths 2017年第2期35卷 149-157页

作者：黄木兰王苏宁兰丽张海龙史忠华陈耀强 Key Laboratory of Green Chemistry & Technology Ministry of EducationCollege of ChemistrySichuan UniversityChengdu 610064China College of Chemical Engineering Sichuan UniversityChengdu 610064China Center of Engineering of Vehicular Exhaust Gases Abatement Chengdu 610064China Center of Engineering of Environmental Catalytic Material Chengdu 610064China

Fresh Pd/CeO/AlOclose coupled catalyst was prepared by the stepwise impregnation method and calcined at 550 °C for 3 h, which was then pretreated at 700, 800, and 900 °C for 3 h, respectively. Finally, these pretreated catalysts were aged at 1000 °C for 3 h to study their anti-aging properties. The catalytic activities of the catalysts were investigated detailedly, and the results showed that the catalyst pretreated at 800 °C before aging treatment possessed the best anti-aging performance for CHoxidation. XRD and XPS results indicated that well-crystallized CeOparticles were formed during calcinations at 800 °C, which made CeOan effective promoter. HRTEM revealed that Pd particles found on the edge of CeOover the aged catalyst pretreated at 800 °C were relatively smaller than those over the catalysts without pretreatment. H-TPR and XPS results also implied that the interaction between well-crystallized CeOand Pd suppressed the deactivation of PdO sites and further enhanced the catalytic performance.

关键词： pretreatment temperature C_3H_8 oxidation anti-aging properties close-coupled catalyst rare earths

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