检索结果-南通市图书馆

A likely candidate of type Ia supernova progenitors: the X-ray pulsating companion of the hot subdwarf HD 49798

在线全文

学校读者我要写书评

暂无评论

Research in Astronomy and Astrophysics 2010年第7期10卷 681-688页

作者： Bo wang Zhan-wen Han National Astronomical Observatories / Yunnan Observatory Chinese Academy of Sciences Kunming 650011 China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences Kunming 650011 China Graduate University of Chinese Academy of Sciences Beijing 100049 China

HD 49798 is a hydrogen depleted subdwarf 06 star and has an X-ray pulsating companion （RX j0648.0-4418）. The X-ray pulsating companion is a massive white dwarf. Employing Eggleton＇s stellar evolution code with the optically thick wind assumption, we find that the hot subdwarf HD 49798 and its X-ray pulsating companion could produce a type Ia supernova （SN Ia） in future evolution. This implies that the binary system is a likely candidate of an SN Ia progenitor. We also discuss the possibilities of some other WD ＋ He star systems （e.g. V445 Pup and KPD 1930＋2752） for producing SNe Ia.

关键词： binaries close -- stars individual (HD 49798) -- stars evolution -- supernovae general -- white dwarfs

Pollen Morphology of Pedicularis ***,a Group Endemic to the Eastern Himalaya-Hengduan Mountains Region

在线全文

学校读者我要写书评

暂无评论

journal of Integrative Plant Biology 2008年第2期50卷 244-252页

作者： wen-Bin Yu Hong wang Key Laboratory of Biodiversity and Biogeography Kunming Institute of Botany Chinese Academy of Sciences Kunming 650204 China Graduate University of Chinese Academy of Sciences Beijing 100049 China

Pedicularis sect. Cyathophora is a distinctive group endemic to the eastern Himalaya-Hengduan Mountains region. It was regarded as a ＇grex＇ or section and included all four general corolla types of Pedicularis. A unique feature of it is that the leaf and bract bases are fused together to form a cup-like structure around the stem at each node. Pollen morphology of seven species in sect. Cyathophora was investigated by scanning electron microscopy （SEM） and light microscopy （LM）. Two different pollen apertures could be distinguished （i.e. trisyncolpate and bisyncolpate） using LM, while examination with SEM made it possible to recognize three types of exine ornamentation （i.e. microscabrate, microfoveolate and microreticulate）. The microfoveolate exine ornamentation was found in trisyncolpate pollen grains for the first time. Possible relationships between pollen data and the corolla types were discussed. Comparisons of floral and phyllotaxy characters of the genus Pedicularis, together with the pollen characters of sect. Cyathophora, could help us to better understand the evolutionary trends in Pedicularis.

关键词： eastern Himalaya Hengduan Mountains Pedicualns pollen morphology sect. Cyathophora.

Effect of extrusion ratio on the microstructure and texture evolution of AZ31 magnesium alloy by the staggered extrusion(SE)

在线全文

学校读者我要写书评

暂无评论

journal of Magnesium and Alloys 2020年第4期8卷 1304-1313页

作者： Yan-peng wang Feng Li Ye wang Xue-wen Li wen-win Fang School of Materials Science and Engineering Harbin University of Science and TechnologyNo.4Lin Yuan StreetXiang FangHarbinHeilongjiang 150040China Key Laboratory of Advanced Manufacturing and Intelligent Technology Ministry of EducationHarbin University of Science and TechnologyHarbin 150080China

There are many problems with the conventional processes of magnesium alloy bending products,such as long processes and difficulty in controlling the product *** paper provides a staggered extrusion(SE)process to solve the above manufacturing *** effects of different extrusion ratios(λ)on the AZ31 magnesium alloy bending products prepared by the SE process was investigated in this *** results show that the bending radii of the AZ31 Mg bending products increase with the increase ofλat the same staggered distance(h=16 mm).When A is in creased from 11.11 to 44.44,the average bending radius of bending products is decreased from 14.7 mm to 9 mm,and the average grain size is decreased by 59.43%.After the SE process,the extruded fiber texture of the AZ31 Mg bending products is obvious,and the deformed texture is a mixed texture of{0001}(10-10)deformation texture and{10-11}(11-20)recrystallization *** results of XRD and EBSD showed that pyramidal slip is an important mode of crystal slip systems in AZ31 magnesium alloys during the SE *** provided a scientific basis for forming AZ31 Mg alloy bending products with excellent microstructure by the SE process.

关键词： Magnesium alloy Staggered extrusion(SE) Bending behavior Texture Slip

Enrichment of anammox biomass during mainstream wastewater treatment driven by achievement of partial denitrification through the addition of bio-carriers

在线全文

学校读者我要写书评

暂无评论

journal of Environmental Sciences 2024年第3期137卷 181-194页

作者： Yuqing Ma Bo wang Xiaodi Li Shuo wang wen wang Yongzhen Peng National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology Engineering Research Center of BeijingBeijing University of TechnologyBeijing 100124China

Anammox is widely considered as the most cost-effective and sustainable process for nitrogen ***,how to achieve the enrichment of anammox biomass remains a challenge for its large-scale application,especially in mainstream wastewater *** this study,the feasibility of enrichment of anammox biomass was explored through the realization of partial denitrification and the addition of *** using ordinary activated sludge,a sequencing batch reactor(SBR)followed by an up-fow anaerobic sludge bed(UASB)was operated at 25±2℃ for 214 *** long-term operation was divided into five phases,in which SBR and UASB were started-up in Phases I and II,*** eliminating oxygen and adjusting the infow ratios in Phases III-V,advanced nitrogen removal was achieved with the effuent total nitrogen being 4.7 mg/L and the nitrogen removal efficiency being 90.5%in Phase *** in-situ and ex-situ activity tests demonstrated the occurrence of partial denitrification and ***,16S rRNA high-throughput sequencing analysis revealed that Candidatus Brocadia was enriched from below the detection limit to in biofilms(0.4%in SBR,2.2%in UASB)and the foc sludge(0.2%in SBR,1.3%in UASB),while Thauera was mainly detected in the foc sludge(8.1%in SBR,8.8%in UASB),which might play a key role in partial ***,this study provides a novel strategy to enrich anammox biomass driven by rapid achievement of partial denitrification through the addition of bio-carriers,which will improve large-scale application of anammox processes in mainstream wastewater treatment.

关键词： Enrichment Anammox biomass Bio-carriers Partial denitrification Mainstream wastewater

区域视角下跨境电商产业集聚效率研究——基于超效率SBM-Malmquist模型分析

在线全文

学校读者我要写书评

暂无评论

江苏商论 2025年第1期 43-47,52页

作者：曾雯汪明艳上海工程技术大学管理学院上海201620

跨境电商在国际贸易转型发展中起着至关重要的作用,而长三角、京津冀、珠三角区域作为中国跨境电商头部经济区在外贸中表现十分活跃。因此为进一步了解跨境电商产业集聚状况,本文选取2016—2021年长三角、京津冀、珠三角三大经济区面板... 详细信息

跨境电商在国际贸易转型发展中起着至关重要的作用,而长三角、京津冀、珠三角区域作为中国跨境电商头部经济区在外贸中表现十分活跃。因此为进一步了解跨境电商产业集聚状况,本文选取2016—2021年长三角、京津冀、珠三角三大经济区面板数据,运用超效率SBM-Malmquist模型从静态和动态两个维度对三大经济区跨境电商集聚效率进行评价。结果显示,跨境电商集聚效率整体表现为珠三角>长三角>京津冀,而纯技术效率和规模效率是拉开差异的主要原因。应该着力推动跨境电商集群均衡发展,加强三大经济区内特色品牌和优势资源互通、技术扩散和知识溢出,强化区域间协同合作。

关键词：跨境电商产业集聚三大经济区超效率SBM-Malmquist模型

Microstructure and oxidation behavior of carbon fiber reinforced SiC composite（C_f/SiC） with Mo–57Si–10B oxidation protection coating

在线全文

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2022年第1期32卷 43-53页

作者： Sihan wen Ying wang jiangbo Sha School of Materials Science and Engineering Beijing University of Aeronautics and Astronautics Key Laboratory of Aerospace Materials and Performance(Ministry of Education) Aerospace Research Institute of Materials & Processing Technology

Mo–57Si–10B（at.%） coating was prepared by the spark plasma sintering（SPS） technique on a 2D woven Cf/Si C composite, and the oxidation behavior of the bare and the coated Cf/SiC samples at 1300°C were *** coating was composed of a fine MoSi2/Mo B/SiO2/Mo2B5out layer and the inner SiO2interface layer. The mass gain percentage was approximately 0.25% after oxidation at 1300°C for 100 h. The coated Cf/Si C substrate was effectively protected, owing to the rapid formation of the dense and protective borosilicate layer on the coating, the excellent microstructure stability of the coating and the inner SiO2interface layer.

关键词： Ceramic-matrix composites High-temperature properties Electron microscopy Microstructures Interface

Strange quark star and the parameter space of the quasi-particle model

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2021年第10期73卷 125-131页

作者： wen-Hua Cai Qing-Wu wang College of physics Sichuan UniversityChengdu 610064China

The properties of strange quark stars are studied within the quasi-particle model. Taking into account chemical equilibrium and charge neutrality, the equation of state(EOS) of(2+ 1)-flavor quark matter is obtained. We illustrate the parameter spaces with constraints from two aspects: one is based on the astronomical results of PSR j0740+ 6620 and GW 170 817,and the other is based on the constraints proposed from the theoretical study of a compact star that the EOS must ensure the tidal deformability Λ_(1.4)=190_(-120)^(+390) and support a maximum mass above 1.97M⊙. It is found that neither type of constraints can restrict the parameter space of the quasi-particle model in a reliable region and thus we conclude that the low mass compact star cannot be a strange quark star.

关键词： strange quark compact star tidal deformability quasi-particle model neutron star

Structure, biochemical function, and signaling mechanism of plant NLRs

在线全文

学校读者我要写书评

暂无评论

Molecular Plant 2023年第1期16卷 75-95页

作者： jizong wang wen Song jijie Chai State Key Laboratory of Protein and Plant Gene Research School of Advanced Agricultural SciencesPeking UniversityBeijing 100871China Tsinghua-Peking joint Center for Life Sciences Center for Plant BiologySchool of Life SciencesTsinghua UniversityBeijing 100084China Institute of Biochemistry University of Cologne50674 CologneGermany Max Planck Institute for Plant Breeding Research 50829 CologneGermany Peking University Institute of Advanced Agricultural Sciences Shandong Laboratory of Advanced Agricultural Sciences at WeifangWeifangShandong 261000China

To counter pathogen invasion,plants have evolved a large number of immune receptors,including membrane-resident pattern recognition receptors(PRRs)and intracellular nucleotide-binding and leucine-rich repeat receptors(NLRs).Our knowledge about PRR and NLR signaling mechanisms has expanded significantly over the past few *** NLRs form multi-protein complexes called resistosomes in response to pathogen effectors,and the signaling mediated by NLR resistosomes converges on Ca2+-permeable ***2+-permeable channels important for PRR signaling have also been *** findings highlight a crucial role of Ca2+in triggering plant immune *** this review,we first discuss the structural and biochemical mechanisms of non-canonical NLR Ca2+channels and then summarize our knowledge about immune-related Ca2+-permeable channels and their roles in PRR and NLR *** also discuss the potential role of Ca2+in the intricate interaction between PRR and NLR signaling.

关键词： plant immunity PRR NLR resistosome Ca2+-permeable channels Ca2+signaling second messenger

Visualization of the protective role of estrogen against female liver fibrosis via an ER viscosity NIR fluorescent probe

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

Science China Chemistry 2025年第1期 360-368页

作者： Zheng Liu Changyu Zhang Zipeng Li Wanying Ma jia Liu Xiang Xia Ning Xu wen Sun jianjun Du jiangli Fan Xiaojun Peng State Key Laboratory of Fine Chemicals Dalian University of Technology Ningbo Institute of Dalian University of Technology

Endoplasmic reticulum(ER) viscosity has emerged as a new potential biomarker for hepatic fibrosis(HF). Herein, we report the first ER-targeting viscosity-responsive near-infrared(NIR) fluorescent probe HBT-PP for investigations of HF *** twisted intramolecular charge transfer(TICT) and the excited state intramolecular proton transfer(ESIPT) are combined to endow HBT-PP with the selective response towards viscosity(～62-fold) and a super large stokes shift(～320 nm). HBT-PP mainly targets organelle ER and is able to image the drug-or alcohol-induced viscosity elevation in living cells. Significantly,HBT-PP was successfully applied to visualize the gender difference in HF and the protective role of estrogen in restraining HF progression. Of note, after 10 min of stain with HBT-PP, HF lesions showed a stage-based response, indicating the potential of this probe in fast and early diagnosis of HF. These results clearly demonstrated the promising application of HBT-PP as a new tool for exploring ER viscosity-involved physiological and pathological processes.

关键词：

同方期刊数据库