检索结果-南通市图书馆

chinese Journal of Aeronautics 2007年第2期20卷 115-119页

作者： XU Fu-min wu Lawrence chi-man HAN Guang-wei TAN Yi State Key Laboratory of Materials Modification by Laser Ion and Electron Beams School of Materials Science and Engineering Dalian University of Technology Dalian 116024 China Department of Physics and Materials Science City University of Hongkong Kowloon HK SAR China Central Iron and Steel Research Institute Beijing 100081 China

The compression creep deformation of the high volume fraction of SiC particles reinforced AI-Mg-Si composite fabricated by pressure-less infiltration was investigated. The experimental results show that the creep stress exponents are very high at temperatures of 673 K, 723 K and 773 K, and if taking the threshold stress into account, the true stress exponent of minimum creep strain rate is still approximately 5, although the volume fraction of reinforcements is very high. The creep strain rate in the high volume fraction reinforced aluminum alloy matrix composites is controlled by matrix lattice diffusion. It is found that the creep-strengthening effect of high volume fraction of silicon carbide particles is significant, although the particles do not form effective obstacles to dislocation motion.

关键词： composite creep SiC aluminum

Summer Monsoon Indices on June Rainfall in Hong Kong and Its Vicinity

在线全文

学校读者我要写书评

暂无评论

Journal of Meteorological Research 2016年第5期30卷 789-799页

作者： wu man-chi TONG Hang-wai LEE Tsz-cheung Hong Kong Observatory Hong Kong China

Climatologically, June is usually the wettest month in Hong Kong. With significant interannual variation of the summer monsoon, the rainfall variability in June is also large. As Hong Kong is in close proximity to the peripheries of different monsoon regions, the variability of June rainfall largely depends on the relative strength of various monsoon systems. In the present study, a new index comparing the relative condition of the western North Pacific summer monsoon and the South china Sea summer monsoon is developed based on the difference between the respective monsoon indices WNPMI （western North Pacific summer monsoon index） and UMI （unified monsoon index）. It is shown that June rainfall in Hong Kong and its vicinity is better correlated with this new index than either WNPMI or UMI alone. Based on the signs of the new index in conjunction with those of WNPMI and UMI, a framework to stratify the monsoon conditions into different configurations together with a simple scheme to summarize the associated rainfall responses is formulated. This study highlights how the rainfall variability on a local or regional scale can be quantified by the broad-scale conditions of different monsoon systems.

关键词： Hong Kong South china Sea summer monsoon western North Pacific summer monsoon mon- soon index June rainfall bootstrap regional monsoon

AN OBSERVATIONAL STUDY OF THE CHANGES IN THE INTENSITY AND MOTION OF TROPICAL CYCLONES CROSSING LUZON

在线全文

学校读者我要写书评

暂无评论

Tropical Cyclone Research and Review 2015年第3期4卷 95-109页

作者： wu man-chi CHOY CHUN-WING Hong Kong Observatory

Tropical cyclones(TCs) moving across Luzon from east to west are likely to affect Hong Kong. As such, it is important for forecasters take into account the likely changes in intensity and movement characteristics of TCs crossing Luzon. 50 TCs in the period 1980-2014 were examined to determine the effect of Luzon’s terrain on their intensity and *** results indicated that TCs generally weakened as they passed through the terrain of Luzon. The decrease in the maximum sustained winds(MSW) for TCs with intensity of severe tropical storms or below was normally < 10 knot. For typhoons, the decrease in the MSW was usually ≥10 knot. The study also showed that TCs moving across Luzon were likely to accelerate(decelerate) as they approached(moved away) from Luzon. Furthermore, while there was a slight bias for TCs to defl ect leftwards on leaving Luzon, a signifi cant negative correlation was found between the defl ection tendency before and after crossing Luzon. A TC defl ected to the right(left) before landfall was likely to defl ect to the left(right) after leaving Luzon. Also, defl ection upon/near landfalling is found to be related to the intensity, moving speed and the direction of motion of a TC.

关键词： AN OBSERVATIONAL STUDY OF THE CHANGES IN THE INTENSITY AND MOTION OF TROPICAL CYCLONES CROSSING LUZON AP TC Figure

Brain region-specific roles of brain-derived neurotrophic factor in social stress-induced depressive-like behavior

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

Neural Regeneration Research 2025年第1期20卷 159-173页

作者： man Han Deyang Zeng Wei Tan Xingxing Chen Shuyuan Bai Qiong wu Yushan Chen Zhen Wei Yufei Mei Yan Zeng Brain Science and Advanced Technology Institute Wuhan University of Science and TechnologyWuhanHubei ProvinceChina Geriatric Hospital Affiliated to wuhan University of Science and Technology WuhanHubei ProvinceChina School of Public Health Wuhan University of Science and TechnologyWuhanHubei ProvinceChina

Brain-derived neurotrophic factor is a key factor in stress adaptation and avoidance of a social stress behavioral *** studies have shown that brain-derived neurotrophic factor expression in stressed mice is brain region–specific,particularly involving the corticolimbic system,including the ventral tegmental area,nucleus accumbens,prefrontal cortex,amygdala,and *** how brain-derived neurotrophic factor participates in stress processing in different brain regions will deepen our understanding of social stress *** this review,we discuss the expression and regulation of brain-derived neurotrophic factor in stress-sensitive brain regions closely related to the pathophysiology of *** focused on associated molecular pathways and neural circuits,with special attention to the brain-derived neurotrophic factor–tropomyosin receptor kinase B signaling pathway and the ventral tegmental area–nucleus accumbens dopamine *** determined that stress-induced alterations in brain-derived neurotrophic factor levels are likely related to the nature,severity,and duration of stress,especially in the above-mentioned brain regions of the corticolimbic ***,BDNF might be a biological indicator regulating stress-related processes in various brain regions.

关键词： amygdala chronic mild stress chronic social defeat stress corticolimbic system depression hippocampus medial prefrontal cortex nucleus accumbens social stress models ventral tegmental area

g-C_(3)N_(4)nanosheets coupled with CoSe_(2)as co-catalyst for efficient photooxidation of xylose to xylonic acid

在线全文

学校读者我要写书评

暂无评论

Green Energy & Environment 2025年第1期10卷 231-238页

作者： Qi Hao Yijun Liu Ren Zou Ge Shi Shilian Yang Linxin Zhonga wu Yang Xiao chi Yunpeng Liu Shimelis Admassie Xinwen Peng State Key Laboratory of Pulp and Paper Engineering South China University of TechnologyGuangzhou510641GuangdongChina Hainan Key Laboratory of Storage&Processing of Fruits and Vegetables Agricultural Products Processing Research InstituteChinese Academy of Tropical Agricultural SciencesZhanjiangGuangdong524001China Department of Chemistry and Centre for Advanced 2D Materials(CA2DM)National University of Singapore 3 Science Drive 3 Singapore117543Singapore School of Materials Science and Hydrogen Energy Foshan UniversityFoshan528231GuangdongChina Department of Chemistry Addis Ababa UniversityPO BOX 1176Addis AbabaEthiopia

Photocatalysis has emerged as an effective approach to sustainably convert biomass into value-added ***_(2)is a promising nonprecious,efficient cocatalyst for photooxidation,which can facilitate the separation of photogenerated electron–holes,increase the reaction rates,and enhance photocatalytic *** this work,we synthesized a stable and efficient photocatalysis system of CoSe_(2)/g-C_(3)N_(4)through attaching CoSe_(2)on g-C_(3)N_(4)sheets,with a yield of 50.12%for the selective photooxidation of xylose to xylonic *** light illumination,the photogenerated electrons were prone to migrating from g-C_(3)N_(4)to CoSe_(2)due to the higher work function of CoSe_(2),resulting in the accelerated separation of photogenerated electron–holes and the promoted ***,this study reveals the unique function of CoSe_(2),which can significantly promote oxygen adsorption,work as an electron sink and accelerate the generation of$O2-,thereby improving the selectivity toward xylonic acid over other *** work provides useful insights into the design of selective photocatalysts by engineering g-C_(3)N_(4)for biomass high-value utilization.

关键词： Biomass photooxidation Hemicelluloses Xylose g-C_(3)N_(4) Xylonic acid

Tectonic modes of mantle convection and their implications for Earth's tectonic evolution based on three-dimensional numerical simulations

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 Earth Sciences 2025年第1期68卷 270-296页

作者： Song XIANG Jinshui HUANG Bingcheng wu School of Earth and Space Sciences University of Science and Technology of China CAS Center of Excellence in Comparative Planetary Studies

Five tectonic modes of mantle convection are obtained and analyzed with three-dimensional numerical models in a spherical shell domain. The five tectonic convective modes are non-plate mobile-lid, plate-like mobile-lid, episodic plate-like mobile-lid, episodic stagnant-lid, and stagnant-lid convective modes, respectively. The typical characteristics of these five tectonic modes and their numerical classification criteria based on plateness, mobility, and their standard deviations are presented and discussed. The results show that the yield stress of the lithosphere has profound effects on the tectonic convective *** the gradual increase of yield stress, the tectonic mode of mantle convection changes from one to another sequentially through the aforementioned five modes. Additionally, as the Rayleigh number increases, the range of yield stress for the platelike mobile-lid convective mode decreases, and the dimensionless transition stress between different tectonic modes ***, the dimensional transition stress between the non-plate mobile-lid convective mode and plate-like mobile-lid convective mode increases with the increase of Rayleigh number, but decreases between other tectonic modes. Furthermore, we find that the transition stress between different tectonic modes is inversely proportional to the internal heating rate, with the transition stress decreasing as the internal heating rate increases. The fitting analysis of the transition stress between tectonic modes shows that Earth's current plate tectonics correspond to a lithospheric yield stress of 150–250 MPa, which aligns with the strength of serpentinized mantle rock determined by experimental petrography. If the Archean mantle was 300°C warmer than it is today, then the Earth was in an episodic stagnant-lid convective mode. The tectonic evolution of the Earth's surface is closely related to the lithospheric strength and the process of thermal evolution. If the lithospheric strength w

关键词： Tectonic mode of mantle convection Plate-like mobile-lid convection Episodic plate-like mobile-lid convection Episodic stagnant-lid convection Plate tectonics and tectonic evolution of the Earth

Sex-dependent alterations in extracellular vesicles linking chronic spinal cord injury to brain neuroinflammation and neurodegeneration

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Neural Regeneration Research 2025年第2期20卷 483-484页

作者： Yun Li Junfang wu Department of Anesthesiology&Shock Trauma and Anesthesiology Research(STAR)CenterUniversity of Maryland School of MedicineBaltimoreMDUSA

Traumatic spinal cord injury(SCI)is a devastating exogenous injury with long-lasting consequences and a leading cause of death and disability *** in assistive technology,rehabilitative interventions,and the ability to identify and intervene in secondary conditions have significantly increased the long-term survival rate of SCI patients,with some people even living well into their seventh or eighth *** survival changes have led neurotrauma researchers to examine how SCI interacts with brain *** health and epidemiological data showed that patients with long-term SCI can have a lower life expectancy and quality of life,along with a higher risk of comorbidities and complications.

关键词： alterations inflammation injury

Deciphering fungal metabolon coupling tandem inverse-electrondemand Diels-Alder reaction and semipinacol rearrangement for the biosynthesis of spiro polycyclic alkaloids

在线全文

学校读者我要写书评

暂无评论

Science china Chemistry 2025年第1期68卷 288-296页

作者： Shuai Liu Wen-Qiang Xu Ying-Tong Di man-Cheng Tang Ding-Kang Chen Ming-Ming Cao Yao-Wen Chang Hong-Yu Tang Chun-Mao Yuan Jun-Bo Yang Zhi-Li Zuo Han Guo Zi-Fei Xu Ying Zeng Yun-Dong wu Xiao-Jiang Hao Key Laboratory of Phytochemistry and Natural Medicines (chinese Academy of Sciences) Kunming Institute of Botany Chinese Academy of Sciences University of chinese Academy of Sciences Lab of Computational Chemistry and Drug Design State Key Laboratory of Chemical Oncogenomics Peking University Shenzhen Graduate School Shenzhen Bay Laboratory State Key Laboratory of Microbial Metabolism School of Life Sciences & Biotechnology Shanghai Jiao Tong University State Key Laboratory of Functions and Applications of Medicinal Plants Guizhou Medical University Molecular Biology Experimental Center Germplasm Bank of Wild Species in Southwest China Kunming Institute of Botany Chinese Academy of Sciences Yunnan Key Laboratory for Wild Plant Resources Kunming Institute of Botany Chinese Academy of Sciences Research Unit of Chemical Biology of Natural Anti-Virus Products Chinese Academy of Medical Sciences

In the intricate process of natural product biosynthesis, a metabolon can enhance metabolic flux by associating sequential enzymes. A fungal metabolon, comprising of flavin-dependent monooxygenase Spe F and P450 monooxygenase Spe G, is identified in the biosynthesis of spiro polycyclic alkaloids(+)-notoamide B and its diastereomer(+)-versicolamide B. Using notoamide E as a substance, Spe F/Spe G metabolon can control the stereoselectivity of its 2,3-epoxidation, followed by hydrogen atom ion at C-17 to generate reactive epoxide tau-m A with dienyl iminium unit. Subsequently,(+)-notoamide B and(+)-versicolamide B are produced via tandem nonenzymatic inverse-electron-demand Diels-Alder reaction and semipinacol rearrangement. This provides the first example of metabolon in the biosynthesis of spiro-prenylated indole alkaloids.

关键词： metabolon Diels-Alder reaction semipinacol rearrangement biosynthesis notoamides spiro polycyclic alkaloids

Crustal magma oxidation state and endowments in porphyry copper deposits

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science china Earth Sciences 2025年第1期68卷 226-236页

作者： Yumin AI Massimo chiARADIA Chao wu Huayong CHEN Key Laboratory of Mineralogy and Metallogeny Guangzhou Institute of Geochemistry Chinese Academy of Sciences University of chinese Academy of Sciences Department of Earth Sciences University of Geneva Guangdong Provincial Key Laboratory of Mineral Physics and Materials

Porphyry copper deposits（PCDs） supply the majority of the world's copper（Cu） as well as significant amounts of molybdenum（Mo） and gold（Au）. The formation of these deposits is controlled by a variety of geological factors, among which the magmatic oxidation is one of the focuses of current research. This study investigates the redox characteristics of arc magmas by analyzing the ratio of vanadium（V） to scandium（Sc） and its correlation with the oxygen fugacity （fO2） of magmas from arcs of various crustal thicknesses globally. We compiled an extensive dataset of published V/Sc values and studied the partition coefficients of Vand Sc between minerals and silicate melts across various magmatic environments. The results demonstrate that fractional crystallization of magnetite markedly reduces V/Sc values of the residual melt. Furthermore, magnesium number（Mg#） at the onset of magnetite fractionation is strongly positively correlated with fO2of the equilibrium magma. Based on this,the oxidation of arc magmas from different crustal thicknesses can be evaluated. The result suggests that magmas generated in crusts thicker than 20 km tend to be more oxidized with increasing crust thickness. This trend is attributed to enhanced intracrustal differentiation processes involving garnet and amphibole, particularly in mature island and continental arcs. In contrast,magmas in thinner arc crusts（<20 km）, which are significantly influenced by subducted slab materials, display higher oxidation states than most of their thicker crust counterparts. These findings suggest that both subduction dynamics and crustal thickness play a vital role in determining the oxidation state of arc magmas and, consequently, their capacity to generate PCDs. Highly oxidized, primitive arc magmas are less favorable for PCD formation due to that they tend to experience magnetite fractionation and thus sulfide saturation in the early stage of magma evolution, a process leading to copper depletion. On the contra

关键词： Magma evolution V/Sc systematics Magnetite Oxygen fugacity Porphyry copper deposits

A Verifiable Trust-Based CP-ABE Access Control Scheme for Cloud-Assisted Renewable Energy Systems

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Computers, Materials & Continua 2025年第1期82卷 1211-1232页

作者： Jiyu Zhang Kehe wu Ruomeng Yan Zheng Tian Yizhen Sun Yuxi wu Yaogong Guo Department of Control and Computer Engineering North China Electric Power UniversityBeijing102206China State Grid Information&Communication Company of Hunan Electric Power Corporation Changsha410118China State Grid Hunan Electric Power Corporation Chenzhou Power Supply Branch Chenzhou423000China

Renewable Energy Systems(RES)provide a sustainable solution to climate warming and environmental pollution by enhancing stability and reliability through status acquisition and analysis on cloud platforms and intelligent processing on edge servers(ES).However,securely distributing encrypted data stored in the cloud to terminals that meet decryption requirements has become a prominent research ***,managing attributes,including addition,deletion,and modification,is a crucial issue in the access control scheme for *** address these security concerns,a trust-based ciphertext-policy attribute-based encryption(CP-ABE)device access control scheme is proposed for RES(TB-CP-ABE).This scheme effectivelymanages the distribution and control of encrypted data on the cloud through robust attribute key *** introducing trust management mechanisms and outsourced decryption technology,the ES system can effectively assess and manage the trust worthiness of terminal devices,ensuring that only trusted devices can participate in data exchange and access sensitive ***,the ES system dynamically evaluates trust scores to set decryption trust thresholds,thereby regulating device data access permissions and enhancing the system’s *** validate the security of the proposed TB-CP-ABE against chosen plaintext attacks,a comprehensive formal security analysis is conducted using the widely accepted random oraclemodel under the decisional q-Bilinear Diffie-Hellman Exponent(q-BDHE)***,comparative analysis with other schemes demonstrates that the TB-CP-ABE scheme cuts energy/communication costs by 43%,and scaleswell with rising terminals,maintaining average latency below 50ms,ensuring real-time service *** proposed scheme not only provides newinsights for the secure management of RES but also lays a foundation for future secure energy solutions.

关键词： Access control renewable energy systems(RES) ciphertext-policy attribute-based encryption(CP-ABE) security