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Shortened processing duration of high-performance Sm-Co-Fe-Cu-Zr magnets by stress-aging

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Journal of materials Science & Technology 2022年第11期106卷 70-76页

作者： Xianglong Zhou Tao yuan Tianyu ma Frontier Institute of Science and Technology State Key Laboratory for Mechanical Behavior of Materialsand MOE Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed MatterXi’an Jiaotong UniversityXi’an 710049China The Southwest Applied magnetism Research Institute Mianyang 621000China

Simultaneously achieving high energy product and high coercivity in the 2:17-type Sm-Co-Fe-Cu-Zr high temperature magnets has been closely relied on long-term isothermal aging to develop complete cellu-lar *** this work,we report a novel stress-aging approach that can substantially shorten the aging time to fabricate high-performance Sm-Co-Fe-Cu-Zr *** exhibited by a model magnet Sm_(25) Co_(50.2) Fe_(16.2) Cu_(5.6) Zr_(3.0)(wt.%),applying 90 MPa compressive stress can shorten the aging time from 20 h for conventional isothermal aging to 10 h at the same aging temperature for achieving nearly equiv-alent magnetic *** comparative study between the 10 h-aged samples under stress-containing and stress-free conditions revealed that the stress not only promotes the precipitation of the cell boundary phase that are essential for enhancing the coercivity but also accelerates the dissociation of the cell edge defects that are detrimental to squareness factor,without destroying the[001]crystal-lographic *** microstructural improvements enable the achievement of high-performance with maximum energy product of∼30 MGOe and coercivity above 35 kOe at reduced aging time.

关键词： Permanent magnets Sm-Co magnets Precipitation Stress-aging

Effects of alga polysaccharide capsule shells on in-vivo bioavailability and disintegration

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Chinese Journal of Oceanology and Limnology 2012年第1期30卷 22-28页

作者： LI Ting GUO Shuju ma Lin yuan yi HAN Lijun Institute of Oceanology Chinese Academy of SciencesQingdao 266071China Graduate University of Chinese Academy of Sciences Beijing 100049China Pharmacology Lab of the Affiliated Hospital of Medical College Qingdao University Qingdao 266003China

Gelatin has been used in hard capsule shells for more than a century, and some shortcomings have appeared, such as high moisture content and risk of transmitting diseases of animal origin to people. Based on available studies regarding gelatin and vegetable shells, we developed a new type of algal polysaccharide capsule (APPC) shells. To test whether our products can replace commercial gelatin shells, we measured in-vivo plasma concentration of 12 selected volunteers with a model drug, ibuprofen, using high performance liquid chromatography (HPLC), by calculating the relative bioavailability of APPC and Qualicaps referenced to gelatin capsules and assessing bioequivalence of the three types of shells, and calculated pharmacokinetic parameters with the software DAS 2.0 (China). The results show that APPC shells possess bioequivalence with Qualicaps and gelatin shells. Moreover, the disintegration behavior of four types of shells (APPC, Vegcaps , Qualicaps and gelatin shells) with the content of lactose and radioactive element (99mTc) was observed via gamma-scintigraphic images. The bioavailability and gamma-scintigraphic studies showed that APPC was not statistically different from other vegetable and gelatin capsule shells with respect to in-vivo behavior. Hence, it can be concluded that APPCs are exchangeable with other vegetable and gelatin shells.

关键词： bioavailability bioequivalence Gamma-scintigraphy vegetable capsules gelatin capsules

Natural and human-induced decline and spatio-temporal differentiation of terrestrial water storage over the Lancang-Mekong River Basin

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Journal of Geographical Sciences 2025年第1期 112-138页

作者： CHEN Junxu WANG yuan ZHAO Zhifang FAN Yunjiang LUO Xiaochuan yi Lu FENG Siqi YANG Liang Emlyn Yunnan Key Laboratory of Soil Erosion Prevention and Green Development Yunnan University International Joint Research Center for Karstology Yunnan University School of Engineering Westlake University Department of Geography Ludwig Maximilian University of Munich (LMU)

Due to water conflicts and allocation in the Lancang-Mekong River Basin(LMRB), the spatio-temporal differentiation of total water resources and the natural-human influence need to be clarified. This work investigated LMRB's terrestrial water storage anomaly(TWSA) and its spatio-temporal dynamics during 2002–2020. Considering the effects of natural factors and human activities, the respective contributions of climate variability and human activities to terrestrial water storage change(TWSC) were separated. Results showed that:(1) LMRB's TWSA decreased by 0.3158 cm/a.(2) TWSA showed a gradual increase in distribution from southwest of MRB to middle LMRB and from northeast of LRB to middle LMRB. TWSA positively changed in Myanmar while slightly changed in Laos and China. It negatively changed in Vietnam, Thailand and Cambodia.(3) TWSA components decreased in a descending order of soil moisture, groundwater and precipitation.(4) Natural factors had a substantial and spatial differentiated influence on TWSA over the LMRB.(5) Climate variability contributed 79% of TWSC in the LMRB while human activities contributed 21% with an increasing impact after 2008. The TWSC of upstream basin countries was found to be controlled by climate variability while Vietnam and Cambodia's TWSC has been controlled by human activities since 2012.

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Review of Ultraviolet Non-Line-of-Sight Communication

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China Communications 2016年第6期13卷 63-75页

作者： Renzhi yuan Jianshe ma Shenzhen Graduate School of Tsinghua University Shenzhen 518055China

With rapid advances of solar blind ultraviolet LED and ultraviolet detecting technology in recent years, ultraviolet communication gradually becomes a research hotspot due to its inherent advantages: low solar background noise, non-line-of-sight(NLOS) and good secrecy. The strong scattering characteristics in atmospheric render ultraviolet waveband the ideal choice for achieving NLOS optical communication. This paper reviews the research history and status of ultraviolet communication both in China and abroad, and especially introduces three main issues of ultraviolet communication: channel model, system analysis and design, light sources and detectors. For each aspect, current open issues and prospective research directions are analyzed.

关键词： ultraviolet communication non-line-of-sight scattering model

Negative corrections to black hole entropy from string theory

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Science China(Physics,Mechanics & Astronomy) 2023年第12期66卷 71-76页

作者： Liang ma yi Pang Hong Lu Center for Joint Quantum Studies and Department of Physics School of ScienceTianjin UniversityTianjin 300350China Joint School of National University of Singapore and Tianjin University International Campus of Tianjin UniversityFuzhou 350207China

We report for the first time that in heterotic string compactified on 4-torus or equivalently IIA string compactified on K3,the leading α′corrections to the rotating black string entropy at fixed conserved charges can be *** further implies that the correction to the mass of extremal rotating string is positive,opposite to the standard expectation from the weak gravity *** result suggests that the validity of positivity of entropy shift due to higher order operators depends on other factors omitted previously in the effective field theory analysis.

关键词： supergravities higher-derivative corrections effective theories black holes quantum gravity string theory

A thermoelectric generator and water-cooling assisted high conversion efficiency polycrystalline silicon photovoltaic system

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Frontiers in Energy 2021年第2期15卷 358-366页

作者： Zekun LIU Shuang yuan yi yuan Guojian LI Qiang WANG Key Laboratory of Electromagnetic Processing of materials(Ministry of Education) Northeastern UniversityShenyang 110819China State Key Laboratory of Rolling and Automation Northeastern UniversityShenyang 110819China School of Metallurgy Northeastern UniversityShenyang 110819China Key Laboratory of Electromagnetic Processing of materials of the Ministry of Education Northeastern UniversityShenyang 110819China

Solar energy has been increasing its share in the global energy structure. However, the thermal radiation brought by sunlight will attenuate the efficiency of solar cells. To reduce the temperature of the photovoltaic (PV) cell and improve the utilization efficiency of solar energy, a hybrid system composed of the PV cell, a thermoelectric generator (TEG), and a water-cooled plate (WCP) was manufactured. The WCP cannot only cool the PV cell, but also effectively generate additional electric energy with the TEG using the waste heat of the PV cell. The changes in the efficiency and power density of the hybrid system were obtained by real time monitoring. The thermal and electrical tests were performed at different irradiations and the same experiment temperature of 22°C. At a light intensity of 1000 W/m2, the steady-state temperature of the PV cell decreases from 86.8°C to 54.1°C, and the overall efficiency increases from 15.6% to 21.1%. At a light intensity of 800 W/m2, the steady-state temperature of the PV cell decreases from 70°C to 45.8°C, and the overall efficiency increases from 9.28% to 12.59%. At a light intensity of 400 W/m2, the steady-state temperature of the PV cell decreases from 38.5°C to 31.5°C, and the overall efficiency is approximately 3.8%, basically remain unchanged.

关键词： photovoltaic(PV) thermoelectric generator conversion efficiency hybrid energy systems water-cooled plate(WCP)

Preparation of a cationic azobenzene dye-montmorillonite intercalation compound and its photochemical behavior

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Journal of University of Science and Technology Beijing 2006年第3期13卷 281-286页

作者： Tao Wan yi yuan Wenqiong He College of materials and Chemistry ＆ Chemical Engineering Chengdu University of Technology Chengdu 610059 China

Montmorillonite/cationic azobenzene dye （GTL） intercalation compounds were prepared by the conventional ion exchange method. As compared with that of pure GTL, the thermal stability of the intercalated GTL was greatly enhanced, and the absorption band corresponding to azobenzene group in intercalated GTL shifted towards a longer wavelength by 55 nm, which could be ascribed to the strong conjugation of GTL supramolecular order structure （J cluster） confined in a nanoscale space of montmorillonite interlayer gallery. The microstructures of the resulting intercalation compounds could be successfully controlled by varying the amount of dye loaded as evidenced by the basal spacing of the intercalation compounds. The intercalated azo dye in the montmorillonite interlayer space exhibited reversible trans-to-cis photoisomerization and thermal cis-to-trans reaction. FTIR proved the successful intercalation of GTL into the silicate layer.

关键词： Na-montmorillonite azobenzene intercalation photoisomerization

Multi-scale UDCT dictionary learning based highly undersampled MR image reconstruction using patch-based constraint splitting augmented Lagrangian shrinkage algorithm

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Frontiers of Information Technology & Electronic Engineering 2015年第12期16卷 1069-1087页

作者： Min yuan Bing-xin YANG yi-de ma Jiu-wen ZHANG Fu-xiang LU Tong-feng ZHANG School of Information Science & Engineering Lanzhou University

Recently, dictionary learning(DL) based methods have been introduced to compressed sensing magnetic resonance imaging(CS-MRI), which outperforms pre-defined analytic sparse priors. However, single-scale trained dictionary directly from image patches is incapable of representing image features from multi-scale, multi-directional perspective, which influences the reconstruction performance. In this paper, incorporating the superior multi-scale properties of uniform discrete curvelet transform(UDCT) with the data matching adaptability of trained dictionaries, we propose a flexible sparsity framework to allow sparser representation and prominent hierarchical essential features capture for magnetic resonance(MR) images. Multi-scale decomposition is implemented by using UDCT due to its prominent properties of lower redundancy ratio, hierarchical data structure, and ease of implementation. Each sub-dictionary of different sub-bands is trained independently to form the multi-scale dictionaries. Corresponding to this brand-new sparsity model, we modify the constraint splitting augmented Lagrangian shrinkage algorithm(C-SALSA) as patch-based C-SALSA(PB C-SALSA) to solve the constraint optimization problem of regularized image reconstruction. Experimental results demonstrate that the trained sub-dictionaries at different scales, enforcing sparsity at multiple scales, can then be efficiently used for MRI reconstruction to obtain satisfactory results with further reduced undersampling rate. Multi-scale UDCT dictionaries potentially outperform both single-scale trained dictionaries and multi-scale analytic transforms. Our proposed sparsity model achieves sparser representation for reconstructed data, which results in fast convergence of reconstruction exploiting PB C-SALSA. Simulation results demonstrate that the proposed method outperforms conventional CS-MRI methods in maintaining intrinsic properties, eliminating aliasing, reducing unexpected artifacts, and removing noise. It

关键词： Compressed sensing(CS) magnetic resonance imaging(MRI) Uniform discrete curvelet transform(UDCT) Multi-scale dictionary learning(MSDL) Patch-based constraint splitting augmented Lagrangian shrinkage algorithm(PB C-SALSA)

Quantitative characterization of vertical zonation of Mesozoic granite weathering reservoirs in the coastal area of eastern Fujian Province,China

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Petroleum Science 2023年第5期20卷 2664-2682页

作者： Jing-Song Hu yi-Ming Jiang Hua-Feng Tang Wen-Rui ma Peng Tao Ning-yuan Sun College of Earth Sciences Jilin UniversityChangchun 130061JilinChina Key Laboratory of Mineral Resources Evaluation in Northeast Asia Ministry of Natural ResourcesChangchun 130061JilinChina CNOOC Shanghai Branch Shanghai 200030China

Weathering crust reservoirs have obvious vertical zonation,which is the focus of weathering crust reservoir research,but there is a lack of quantitative characterization *** achieve the quantitative characterization of granite weathering crust reservoir and provide the basis for oil exploration of granite weathering crust buried hill reservoir,in this paper,the vertical zonation of granite weathering crust reservoir is quantitatively divided by testing and analyzing the uniaxial compressive strength(UCS),magnetic susceptibility(MS),permeability,and chemical index of alteration(CIA)of the Mesozoic granite weathering crust in the coastal area of eastern *** results show that the granite weathering crust reservoir can be divided into four zones vertically:a soil zone(SZ),weathered and dissolved zone(WDZ),fracture zone(FZ),and bedrock zone(BZ).A cataclastic area is developed in the FZ and BZ,in which structural fractures are well-developed,the fracture surface density is usually greater than 200 m/m^(2),and the contribution to the fractures in the rock mass is up to about 50%,making this the sweet spot of the *** the SZ,the rocks are loose,and the pores are *** UCS is less than 10 MPa,and the average rate of change of the UCS(Δ_(σ))is *** average permeability is 2823.00 mD,and the average rate of change of the permeability(Δ_(κ))is *** average CIA is 74.9%.The average clay mineral content is 7%.The rocks in the WDZ have been significantly weathered by physical and chemical processes,and the weathering fractures and dissolution pores are *** average UCS is 18.2 MPa,and the averageΔ_(σ)is *** average permeability is 143.80 mD,and averageΔ_(κ)is *** average CIA is 65.3%.The average clay mineral content is 4%.Under the influence of tectonic movement and physical weathering,the rocks in the FZ have developed structural fractures and a few weathered *** average UCS is 57.9 MPa,and the averageΔ_

关键词： Granite weathering crust Vertical zonation of reservoir Quantitative characterization Eastern Fujian Mesozoic granite