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Selection of culture conditions for callus induction and proliferation by somatic embryogenesis of Pinus koraiensis

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Journal of Forestry Research 2021年第2期32卷 483-491页

作者： Fang gao chunxue Peng Hao wang Hailong Shen Ling Yang State Key Laboratory of Tree Genetics and Breeding School of ForestryNortheast Forestry UniversityHarbin 150040People’s Republic of China

The induction and proliferation of embryogenic callus are key steps for large-scale propagation of somatic embryogenesis pathway and long-term preservation of coniferous *** can be induced from immature embryos of Korean pine(Pinus koraiensis *** Zucc.;Pinaceae)as explants,but there are problems,such as low proliferation efficiency,loss of embryogenicity,poor vigor;thus,best conditions for proliferation and culture of immature embryos of Korean pine are not yet *** solve the problems with somatic embryogenesis of Korean pine and determine the best culture conditions for callus induction and proliferation,we varied hormone concentration,subculture cycle of proliferation and other plant growth regulators combinations in media to induce callus formation by megagametophytes of three Korean pine families at different developmental stages,then analyzed the effects on embryogenic callus retention and cell proliferation using a quadratic regression orthogonal rotation *** results showed that the family origin and collection date of explants significantly affected callus induction(induction rate reached 1.67%).Embryogenic maintenance and callus proliferation were best on DCR medium supplemented with 0.25 mg L^(−1)6-benzyl adenine,1 mg L^(−1)naphthaleneacetic acid,30 g L^(−1)sucrose,500 mg L^(−1),L-glutamine,500 mg L^(−1)casein hydrolysis and 6.5 g L^(−1)*** addition,the combination of 2,4-dichlorophenoxyacetic acid+6-benzyl adenine also had a better proliferative effect on *** effects of different combinations of growth regulators on callus proliferation efficiency were significantly *** to new medium every 13–15 days not only maintained robust callus vigor,but also yielded a larger proliferation *** techniques and conditions for embryogenic callus induction and proliferation of Korean determined here will serve as a foundation for establishing a large-scale system for somatic embryogenesis and propagation of

关键词： Korean pine Somatic embryogenesis Embryogenic callus Megagametophytes Embryonic maintenance

Heat treatment and associated early modern human behaviors in the Late Paleolithic at the Shuidonggou site

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Chinese Science Bulletin 2013年第9期58卷 1801-1810页

作者： ZHOU ZhenYu GUAN Ying gao xing wang chunxue Laboratory of Human Evolution the Institute of Vertebrate Paleontology and PaleoanthropologyChinese Academy of Sciences Institute of Archaeology Chinese Academy of Social Sciences Research Center of Chinese Frontier Archaeology of Jilin University

Unearthed artifacts and cultural relics from the Shuidonggou site revealed extensive information and insights regarding the activities of early modern humans.A series of experimental research and physical analysis suggest that stone artifacts from Locality 2 and Locality 12 have undergone heat *** utilization ratio and knapping properties of raw materials were consequently *** treatment technology reflects the production capacities and the survival strategies in the Upper Paleolithic *** discovery indicates the earliest existence of this technology in the East Asia and thus confirms a wider geographic distribution of this technology which provides new perspectives and evidence for understanding the associated early modern human behaviors.

关键词：旧石器时代晚期人类行为水洞沟热处理规范早期遗址热处理技术调制解调器

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Effect of lanthanum addition on microstructure and hardness of brass alloys produced by rheological squeeze casting

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Journal of Rare Earths 2022年第12期40卷 1953-1962,I0006页

作者： Wenjing gao Shuming xing Ying wang School of Mechanical Electronic and Control EngineeringBeijing Jiaotong UniversityBeijing 100044China School of Mechatronics and Vehicle Engineering Zhengzhou University of TechnologyZhengzhou 450044China

The effect of La addition(0-0.30 wt%)on the microstructure and hardness of rheological squeeze casting brass alloys was experimentally *** rheological squeeze casting process is improved by controlling the wall surface crystals and melt flow rate to realise the preparation of semi-solid melt with flow,and a brass alloy workpiece with La is *** microstructure and properties of the brass alloy samples were investigated using metallography,scanning electron microscopy,energy-dispersive X-ray spectroscopy,X-ray diffraction and hardness *** results indicate that the hardness of the rheological squeeze casting brass alloy is increased by 20.4%from 108 to 130 HBW with an increase in the La content from 0 to 0.30 wt%.The micro structural analysis results show that La significantly refines the primary a-phase grains,and the main mechanism is the constitutional undercooling and heterogeneous nucleation caused by the La enrichment in the front of the solid-liquid *** squeeze pressure promotes undercooling,which improves the nucleation rate and affects the solute diffusion and nucleus *** dual effects of these two aspects aggravate the grain refinement process,consequently increasing the number of grain boundaries and improving the hardness of the brass alloy.

关键词： Rheological squeeze casting La Brass alloy Grain refinement Rare earths

Critical-Current Degeneration Dependence on Axial Strain of Bi-based Superconducting Multi-filamentary Composite Tapes

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Chinese Physics Letters 2014年第4期31卷 155-158页

作者： gao Pei-Feng wang xing-Zhe Key Laboratory of Mechanics on Western Disaster and Environment (Ministry of Education) and College of Civil Engineering and Mechanics Lanzhou University Lanzhou 730000

Superconducting materials are always severely restricted in practical engineering applications due to their carrying- current degradation under mechanical loads. Based on Ekin＇s exponential model and Weibull＇s distribution func- tion, we propose an empirical degradation model for describing the mechanical deformation influence on the critical-current of Bi-based superconducting multi-filamentary composite tapes under axial loading. The critical currents of superconducting tapes depending on the axial strain are investigated analytically. It is shown that the predictions by the developed degradation model agree with the experimental data, in the processes of axial mechanical loading and unloading on the samples. The effect of the critical tension and compression damage strains on the normalized critical currents is also discussed.

关键词： CRITICAL currents MULTIFILAMENTARY superconductors WEIBULL distribution SUPERCONDUCTING tape COMPRESSION loads

Technology diffusion and population migration reflected in blade technologies in northern China in the Late Pleistocene

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Science China Earth Sciences 2016年第8期59卷 1540-1553页

作者： LI Feng CHEN FuYou wang YingHua gao xing Key Laboratory of Vertebrate Evolution and Human Origins of Chinese Academy of Sciences Institute of Vertebrate Paleontology and Paleoanthropology Chinese Academy of Sciences Beijing 100044 China Inner Mongolia Museum Hohhot 010010 China

In recent years, the origin and evolution of modern human behaviors have become a common topic of research in Paleolithic archaeology. One important part of modern human behavior, blade technology, was once thought to be unique to modern humans. Recent studies have suggested that variations in blade technology do not fully correspond to modern populations. However, the standardization, diversity, discontinuity in terms of time distribution, and differences in spatial distribution of blade technology give it an important role in discussions of modes of adaptation, diffusion of technology, and population migration of hominins. By categorizing the major blade assemblages in China, we show that there were two blade reduction methods in northern China: the Levallois method and the prismatic method. Dating back 40000–30000 years, the Levallois and prismatic blade method combined to form the characteristics of the early stage of the Upper Paleolithic. Artifacts bearing such characteristics are located in Northwest China, Northeast China, and the Qinghai-Tibet Plateau. The unearthed blades are similar in technological organization and are connected geographically with those discovered in Siberia and Mongolia, which also indicates a distinct border from those discovered in northern China. This fact is suggestive of population immigration. About 29000–25000 years ago, a combination of prismatic blades and microblades was developed in the hinterland of China; however whether it can be regarded as the representative of population migration or only a technological adaption remains undetermined. We suggest that the system of production of different blades should be distinguished in the study of blade assemblages and that different blade methods should not be integrated into a single technical system to discuss technology diffusion and population dispersal.

关键词： North China Late Pleistocene Blade technology Technology diffusion Human migration

Dew measurement and estimation of rain-fed jujube (Zizyphus jujube Mill) in a semi-arid loess hilly region of China

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Journal of Arid Land 2017年第4期9卷 547-557页

作者： wang xing gao Zhiyong wang Youke wang Zhi JIN Shanshan Institute of Soil and Water Conservation Chinese Academy of Sciences and Ministry of Water Resources Department of Water Conservancy Yangling Vocational & Technological College College of Water Resources and Architectural Engineering Northwest A&F University Department of Earth and Environmental Sciences California State University

Dew is an important water source for plants in arid and semi-arid regions. However, information on dew is scarce in such regions. In this study, we explored dew formation, amount, and duration of rain-fed jujube（Zizyphus jujube Mill） trees in a semi-arid loess hilly region of China（i.e., Mizhi County）. The data included dew intensity and duration, relative humidity, temperature, and wind speed measured from 26 July to 23 October, 2012 and from 24 June to 17 October, 2013 using a micro-climate system（including dielectric leaf wetness sensors, VP-3 Relative Humidity/Temperature Sensor, High Resolution Rain Gauge, and Davis Cup Anemometer）. The results show that atmospheric conditions of relative humidity of 〉78% and dew point temperature of 1°C–3°C are significantly favorable to dew formation. Compared with the rainfall, dew was characterized by high frequency, strong stability, and long duration. Furthermore, heavy dew accounted for a large proportion of the total amount. The empirical models（i.e., relative humidity model（RH model） and dew point depression model（DPD model）） for daily dew duration estimation performed well at 15-min intervals, with low errors ranging between 1.29 and 1.60 h, respectively. But it should be noted that the models should be calibrated firstly by determining the optimal thresholds of relatively humidity for RH model and dew point depression for DPD model. For rain-fed jujube trees in the semi-arid loess hilly regions of China, the optimal threshold of relative humidity was 78%, and the optimal upper and lower thresholds of dew point depression were 1°C and 5°C, respectively. The study further demonstrates that dew is an important water resource that cannot be ignored for rain-fed jujube trees and may affect water balance at regional scales.

关键词： dew formation dew amount dew duration jujube plantation empirical models Loess Plateau

Recent advances in metal-organic frameworks for lithium metal anode protection

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Chinese Chemical Letters 2020年第3期31卷 609-616页

作者： Ying Du xing gao Siwu Li Lu wang Bo wang Beijing Key Laboratory of Photoelectronic/Electrophotonic Conversion Materials Key Laboratory of Cluster ScienceMinistry of EducationSchool of Chemistryand Chemical EngineeringBeijing Institute of TechnologyBeijing 100081China

The lithium metal battery has been considered as a promising candidate for next generation ***,safety concerns caused by uncontrollable lithium dendrite growth on lithium anode are severely hampering the commercial ***-organic frameworks(MOFs)become one of the most attractive materials due to the high porosity,structural designability and *** unique open channels and pores as well as functional components in MOFs,the transportation and deposition of lithium ions can be regulated,which leads to enhanced electrochemical prope *** strategies for lithium metal protection are proposed in recent wo rks on applications of MOFs in lithium metal *** this review,we highlight latest key approaches in this field and discuss the prospects for MOFs in advanced Li anodes.

关键词： Metal-organic frameworks Li anode Lithium metal batteries Li dendrite Protection

Effect of order–disorder transition on thermodynamic and electronic properties of σ and χ phases in W–Re alloy: the first-principles calculation

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Tungsten 2025年第1期 195-213页

作者： Zhi-Peng Zhu Dian Jia William Yi wang Jun-Lei Yin xing-Yu gao Shu-Feng Yang Hai-Feng Song Jin-Shan Li State Key Laboratory of Solidification Processing Northwestern Polytechnical University Laboratory of Computational Physics Institute of Applied Physics and Computational Mathematics School of Metallurgical and Ecological Engineering University of Science and Technology Beijing

The Tungsten-Rhenium(W-Re) alloys,celebrated for their high melting point,strength at elevated temperatures,electrical resistivity,and radiation resistance,have been widely utilized in high-temperature components,aerospace,electronics,and nuclear *** constituents of the topologically close-packed(TCP) phases,the sigma phase(σ) and chi phase(χ) formed within W-Re alloys wield considerable influence on the mechanical properties and the stability of the *** calculations were utilized in the present work to explore the structural,thermodynamic,and electronic properties of both ordered and disordered configurations within the σ and χ phases,culminating in a systematic elucidation of the higher phase stability exhibited by the ordered *** is found that the bulk modulus of these two phases is directly proportional to the concentration of Re in the alloy,while the equilibrium volume is inversely *** thermodynamic parameters of the σ and χ phases are calculated via the mean-field potential *** similar trends observed in the isobaric heat capacity,enthalpy increment,and entropy change curves for these two phases suggest they possess comparable thermodynamic *** is noteworthy that the contribution of ionic vibrations predominantly affects the isobaric heat capacity,while the contribution of thermal electronic excitations increases linearly with *** the structure and thermodynamic properties of TCP phases in W-Re alloys at low temperatures has profound significance for optimizing material performance,microstructures features,establishing theoretical foundations,and predicting material behavior.

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A Physical Layer Network Coding Based Tag Anti-Collision Algorithm for RFID System

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Computers, Materials & Continua 2021年第1期66卷 931-945页

作者： Cuixiang wang xing Shao Yifan Meng Jun gao School of Information Engineering Yancheng Institute of TechnologyYancheng224000China School of Computer Nanjing University of Posts and TelecommunicationNanjing210003China Modern Agricultural Resources Intelligent Management and Application Laboratory Huzhou Normal UniversityHuzhou313000China School of Science and Technology Troy UniversityTroy36082USA

In RFID(Radio Frequency IDentification)system,when multiple tags are in the operating range of one reader and send their information to the reader simultaneously,the signals of these tags are superimposed in the air,which results in a collision and leads to the degrading of tags identifying *** improve the multiple tags’identifying efficiency due to collision,a physical layer network coding based binary search tree algorithm(PNBA)is proposed in this *** pushes the conflicting signal information of multiple tags into a stack,which is discarded by the traditional anti-collision *** addition,physical layer network coding is exploited by PNBA to obtain unread tag information through the decoding operation of physical layer network coding using the conflicting information in the ***,PNBA reduces the number of interactions between reader and tags,and improves the tags identification *** analysis and simulation results using MATLAB demonstrate that PNBA reduces the number of readings,and improve RFID identification ***,when the number of tags to be identified is 100,the average needed reading number of PNBA is 83%lower than the basic binary search tree algorithm,43%lower than reverse binary search tree algorithm,and its reading efficiency reaches 0.93.

关键词： Radio frequency identification(RFID) tag anti-collision algorithm physical layer network coding binary search tree algorithm