检索结果-南通市图书馆

Energy Density Dependence of Bonding Characteristics of Selective Laser-Melted Nb–Si-Based Alloy on Titanium Substrate

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2018年第5期31卷 477-486页

作者： Yue-ling Guo Li-Na jia Bin Kong Yong-Lin Huang Hu Zhang School of Materials Science and Engineering Beihang University

Spherical Nb–20Si–24Ti–2Cr–2Al pre-alloyed powders were processed by selective laser melting（SLM） on Ti6Al4V substrates with different energy densities. A series of single tracks and single layers were produced using different processing parameters, including powder size, laser power, scanning speed and hatch distance. Results showed that the pre-alloyed powders ranging from 45 to 75 lm were more applicable to SLM with less balling tendency, in comparison with those between 75 and 180 lm. The increase in linear energy density（LED） resulted in the decrease in contact angle and the increase in the width of single track as well as its penetration depth into the substrate. Smaller hatch distance leaded to a larger remelted part of the former track and a higher volumetric laser energy density. With a thickness of 75.6 lm, an interfacial intermediate layer, enriched in Ti and depleted in Nb, Si, Cr and Al, was formed between the SLM part and the Ti6Al4V substrate. The mechanisms of the elimination of balling phenomenon by employing a higher LED and the interfacial bonding characteristics between Nb–Si-based alloys via SLM and the Ti6Al4V substrate were discussed.

关键词： Nb-Si alloys Selective laser melting Additive manufacture Bonding character Microstructure

Exogenous insulin autoimmune syndrome:A case report and review of literature

在线全文

学校读者我要写书评

暂无评论

World Journal of Clinical Cases 2024年第9期12卷 1691-1697页

作者： ling-ling Xu jia-Xin Chen Jing-Ping Cheng Ni Luo Medical College School of MedicineWuhan University of Science and TechnologyWuhan 430065Hubei ProvinceChina Department of Gerontology CR&WISCO General Hospital Affiliated to Wuhan University of Science and TechnologyWuhan 430080Hubei ProvinceChina

BACKGROUND Insulin autoimmune syndrome(IAS)is a severe manifestation of spontaneous *** is characterized by elevated levels of immune-reactive insulin and highly potent insulin autoantibodies(IAAs),which are induced by endogenous insulin circulating in the *** is distinguished by recurring instances of spontaneous hypoglycemia,the presence of IAA within the body,a substantial elevation in serum insulin levels,and an absence of prior exogenous insulin ***,recent studies show that both conventional insulin and its analogs can induce IAS episodes,giving rise to the notion of nonclassical ***,more attention should be paid to these *** SUMMARY In this case report,we present a rare case of non-classical IAS in an 83-year-old male patient who present with symptoms of a psychiatric *** symptom onset,the patient exhibited Whipple's triad(including hypoglycemia,blood glucose level less than 2.8 mmol/L during onset,and rapid relief of hypoglycemic symptoms after glucose administration).Concurrently,his serum insulin level was significantly elevated,which contradicted his C-peptide *** a comprehensive examination,the patient was diagnosed with exogenous insulin autoimmune *** that the patient had type 2 diabetes mellitus and a history of exogenous insulin use before disease onset,it was presumed that non classical IAS was induced by this *** PubMed database was used to search for previous cases of IAS and non-classical IAS to analyze their characteristics and treatment *** The occurrence of non-classical IAS is associated with exogenous insulin or its analogs,as well as with sulfhydryl *** can be effectively alleviated through the discontinuation of relevant medications,administration of hormones or immunosuppressants,plasma exchange,and lifestyle adjustments.

关键词： Insulin autoimmune syndrome Type 2 diabetes Exogenous insulin Insulin autoantibodies Hypoglycemia Case report

Occurrence of Glyphosate-Resistant Horseweed (Conyza canadensis) Population in China

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Agricultural Sciences in China 2011年第7期10卷 1049-1055页

作者： SONG Xiao-ling WU jia-jun ZHANG Hong-jun QIANG Sheng Weed Research Laboratory Nanjing Agricultural University Nanjing 210095 P.R.China Institute for the Control of Agrochemicals Ministry of Agriculture （CAMA） Beijing 100026 P.R.China

Horseweed （Conyza canadensis）, an invasive alien weed, is one of the main weeds in orchards in China. Although glyphosate has been used for control of horseweed and many other weeds in orchards for more than 25 years in China, a case of glyphosate-resistant horseweed has not been identified in orchard in China so far despite glyphosate-resistant horseweed cases have been reported in some other countries. Seeds of 25 horseweed populations were collected from different orchards with different glyphosate application history. Potted seedlings with 11-13-leaf growth stage were treated with glyphosate at 0.035, 0.07, 0.14, 0.28, 0.56, 1.12, 2.24, 4.48, and 8.96 kg a.i. ha-1. The dosage dependence response curve of each population was constructed with Log-logistic dose response regression equations. The ED50 value of each population was calculated and compared with the susceptible population from China. Different populations had different relative glyphosate-resistant levels which increased with the number of years of glyphosate application. Two populations with the highest resistance levels, 8.28 and 7.95 times, were found in Ningbo, Zhejiang Province, China, where glyphosate was used for weed control in orchards twice each year for 15 yr. The two resistant populations accumulated approximately two to four times less shikimic acid than the two susceptible populations 48 h after glyphosate application.

关键词： horseweed [Conyza canadensis (L.) Cronq.] glyphosate resistance shikimic acid

Evolution of Gold Species in an Au/CeO_2 Catalyst and Its Impact on Activity for CO Oxidation

在线全文

学校读者我要写书评

暂无评论

Chemical Research in Chinese Universities 2010年第3期26卷 453-459页

作者： SUN Yong-an SHEN Yue-nian jia Mei-lin GUO Jin-ling College of Chemistry and Chemical Engineering Inner Mongolia University for Nationalities Tongliao 028043 P. R. China College of Chemistry and Chemical Engineering Inner Mongolia University Hohhot 010021 P. R. China College of Chemistry and Environmental Science lnner Mongolia Normal University Hohhot 010020. P. R. China

An Au/ceria（0.44%, mass fraction） catalyst containing gold ions was prepared by a modified deposition precipitation method, and the evolution of gold ions in the catalyst and its influence on the catalysis of CO oxidation were investigated. It was found that the as-prepared catalyst containing gold ions with high valence could fully oxidize CO at -10 ℃ initially but was deactivated gradually at low temperatures during the reaction with CO or treatment by unpurified air. The deactivation of the catalyst during CO oxidation or treatment of it by unpurified air was independent and progressive at low temperatures while the activity of the catalyst at relatively high temperatures was maintained well. During the reaction with CO or treatment by unpurified air, the XPS results indicate that gold species evolved from high valence to low valence and the diffuse reflectance UV-Vis spectra show that high valence gold was reduced to charged gold clusters, gold clusters grew to small gold crystals and small gold crystals grew to large gold particles. Accordingly, the high valence gold corresponded to the activity at low temperatures and the metallic gold was active and relatively stable at high temperatures. The turnover frequencies（TOF） of the catalysts treated by different methods at 273 K decreased with the evolution of gold species from high valence to low valence, no maximum of TOF was observed although gold particles in the catalyst attained to about 2-3 nm during the treatment. An Au/ceria catalyst with a gold load of 0.87% （mass fraction） maintained a good activity for CO oxidation within 18 h at room temperature. The catalysts were characterized via transmitted electronic microscopy（TEM）, inductively coupled plasma optical emission spectrometry（ICP-OES）, X-ray diffraction（XRD） and BET specific surface area and UV-Vis DRS as well.

关键词： Gold catalyst CO oxidation UV-Vis DRS XPS Gold valence

Thermodynamic optimization and fluid selection of organic Rankine cycle driven by a latent heat source

在线全文

学校读者我要写书评

暂无评论

Journal of Central South University 2017年第12期24卷 2829-2841页

作者： XU Peng LU jian LI Tai-lu ZHU jia-ling School of Energy and Safety Engineering Tianjin Chengjian University Tianjin 300384 China Key Laboratory of Efficient Utilization of Low and Medium Grade Energy Ministry of Education(Tianjin University) Tianjin 300072 China

Organic Rankine cycle(ORC) is applicable for the heat-work conversion. Whereas, there also exist a lot issues that influence the efficiency and the cost of the system. In this work, eleven pure working fluids(as categorized into alkanes, and fluorinated alkanes) are investigated based on the first and second law of thermodynamics. The major objective is to obtain the most suitable working fluid for the latent heat source. The results show that the working fluid is an important factor of the system performance. The heat absorption of the working fluid in the evaporator is inversely proportional to the evaporating temperature, but the thermal and exergetic efficiencies are just the opposite. RC318 has the highest net power output and the lowest outlet temperature of the heat source, but its global warming potential(GWP) value is too high. The cyclohexane shows the highest thermal efficiency among the fluids investigated. Moreover, the figure of merit(FOM) of the isobutane is higher than that of other working fluids. Overall, the cyclohexane shows that the optimal comprehensive performance is more feasible for medium grade heat source in engineering applications.

关键词： organic Rankine cycle working fluids thermodynamics low-temperature evaporating temperature

Fengyun Meteorological Satellite Products for Earth System Science Applications

在线全文

学校读者我要写书评

暂无评论

Advances in Atmospheric Sciences 2021年第8期38卷 1267-1284页

作者： Di XIAN Peng ZHANG ling GAO Ruijing SUN Haizhen ZHANG Xu jia National Satellite Meteorological Center China Meteorological AdministrationBeijing 100081China

Following the progress of satellite data assimilation in the 1990s, the combination of meteorological satellites and numerical models has changed the way scientists understand the earth. With the evolution of numerical weather prediction models and earth system models, meteorological satellites will play a more important role in earth sciences in the future. As part of the space-based infrastructure, the Fengyun (FY) meteorological satellites have contributed to earth science sustainability studies through an open data policy and stable data quality since the first launch of the FY-1A satellite in 1988. The capability of earth system monitoring was greatly enhanced after the second-generation polar orbiting FY-3 satellites and geostationary orbiting FY-4 satellites were developed. Meanwhile, the quality of the products generated from the FY-3 and FY-4 satellites is comparable to the well-known MODIS products. FY satellite data has been utilized broadly in weather forecasting, climate and climate change investigations, environmental disaster monitoring, etc. This article reviews the instruments mounted on the FY satellites. Sensor-dependent level 1 products (radiance data) and inversion algorithm-dependent level 2 products (geophysical parameters) are introduced. As an example, some typical geophysical parameters, such as wildfires, lightning, vegetation indices, aerosol products, soil moisture, and precipitation estimation have been demonstrated and validated by in-situ observations and other well-known satellite products. To help users access the FY products, a set of data sharing systems has been developed and operated. The newly developed data sharing system based on cloud technology has been illustrated to improve the efficiency of data delivery.

关键词： Fengyun meteorological satellite sensor-dependent level 1 product inversion algorithm-dependent level 2 product product validation

Total chemical synthesis of bivalently modified H3 by improved three-segment native chemical ligation

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2020年第5期31卷 1267-1270页

作者： Yong Zheng Fangming Wu Shenglong ling jia-Bin Li changlin Tian High Magnetic Field Laboratory Chinese Academy of SciencesHefei 230031China School of Life Sciences University of Science and Technology of ChinaHefei 230027China jiangsu Key Laboratory of Neuropsychiatric Diseases and College of Pharmaceutical Sciences Soochow UniversitySuzhou 215123China

The H3 bivalent modifications of trimethylationat Lys9 and acetylation at Lys18(H3-K9 Me3-K18 Ac) were identified to collectively recruit TRIM33 in the nodal signaling *** understand the underlying mechanism of TRIM33 recruitment,the nucleosome core particles(NCPs) containing full-length H3-K9 Me3-K18 Ac were indispensable *** we developed a pseudo dipeptide strategy to efficiently prepare peptide segments,facilitating the chemical synthesis of H3-K9 Me3-K18 Ac at a tens of milligram *** synthetic H3-K9 Me3-K18 Ac was then examined by CD spectroscopy,which demonstrated a prominent shift compared to recombinant ***,bivalently modified NCPs were assembled and verified by gel mobility shift assay with good homogeneity.

关键词： Chemical protein synthesis Native chemical ligation Histone H3 Methylation Acetylation Nucleosome core particles

Nano-silica modified lightweight and high-toughness carbon fiber/phenolic ablator with excellent thermal insulation and ablation performance

在线全文

学校读者我要写书评

暂无评论

Defence Technology（防务技术） 2024年第1期31卷 192-199页

作者： Wenjie Xu Wenda Song Xianfeng jia Cheng Ma Jitong Wang Wenming Qiao Licheng ling State Key Laboratory of Chemical Engineering East China University of Science and TechnologyShanghai 200237China School of Chemical Engineering and Materials Changzhou Institute of TechnologyChangzhou 213032China Key Laboratory of Specially Functional Polymeric Materials and Related Technology(Ministry of Education) School of Materials Science and EngineeringEast China University of Science and TechnologyShanghai 200237China

Lightweight and high-toughness carbon fiber/phenolic ablator(CFPA)is required as the Thermal Protection System(TPS)material of aerospace vehicles for next-generation space *** improve the ablative properties,silica sol with good particle size distribution prepared using tetramethoxysilane(TMOS)was blended with natural rubber latex and deposited onto carbon fiber felt,which was then integrated with phenolic aerogel matrix,introducing nano-silica into the framework of *** modified CFPA with a low density of 0.28—0.31 g/cm3exhibits strain-in-fracture as high as 31.2%and thermal conductivity as low as 0.054 W/(m·K).Furthermore,a trace amount of nano-silica could effectively protect CFPA from erosion of oxidizing atmosphere in different high-temperature *** oxyacetylene ablation test of 3000°C for 20 s shows a mass ablation rate of 0.0225 g/s,a linear ablation rate of 0.209 mm/s for the modified CFPA,which are 9.64%and 24.82%lower than the unmodified ***,the long-time butane ablation test of 1200°C for 200 s shows an insignificant recession with mass and linear ablation rate of 0.079 g/s and 0.039 mm/s,16.84%and 13.33%lower than the unmodified ***,the fixed thermocouple in the test also demonstrates a good thermal insulation performance with a low peak back-face temperature of 207.7°C,12.25%lower than the unmodified ***,the nano-silica modified CFPA with excellent overall performance presents promising prospects in high-temperature aerospace applications.

关键词： Nano-silica Carbonfiber Phenolic aerogel Insulation Ablation

A New QP-free Algorithm Without a Penalty Function or a Filter for Nonlinear Semidefinite Programming

在线全文

学校读者我要写书评

暂无评论

Acta Mathematicae Applicatae Sinica 2020年第3期36卷 714-736页

作者： jian-ling LI Zhen-ping YANG jia-qi WU Jin-bao jiaN College of Mathematics and Information Science Guangxi UniversityNanning 530004China School of Mathematics Jiaying UniversityMeizhou 514015China College of Science Guangxi University for NationalitiesNanning 530006China

In this paper,we present a QP-free algorithm without a penalty function or a filter for nonlinear semidefinite *** each iteration,two systems of linear equations with the same coefficient matrix are solved to determine search direction;the nonmonotone line search ensures that the objective function or constraint violation function is sufficiently *** is no feasibility restoration phase in our algorithm,which is necessary for traditional filter *** proposed algorithm is globally convergent under some mild *** numerical results indicate that the proposed algorithm is comparable.

关键词： nonlinear semidefinite programming QP-free penalty-free nonmonotone line search global convergence