检索结果-南通市图书馆

Formation of spheroidal microstructure in semi-solid state and thixoforming of 7075 high strength aluminum alloy

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2015年第10期34卷 710-716页

作者： Chang-Peng Wang ze-jun tang Hua-Sheng Mei Ling Wang Rong-Qiang Li Di-Fan Li Environmental Testing Center No. 59 Institute of China Ordnance Industry Corrosion and Protection Center University of Science and Technology Beijing Mechanical and Electrical College Nanjing University of Aeronautics & Astronautics

The effects of isothermal holding process on the microstructure evolution of semi-solid 7075 strength aluminum alloy produced by the recrystallisation and partial remelting(RAP) process were investigated. Tensile mechanical properties of as-received and thixoformed alloys at room temperature were examined. The results show that the microstructure of as-received alloy exhibits remarkable orientation along the deformation *** the increase of isothermal holding time, the solid particle grain size continuously increases and the degree of spheroidization also improves. Coalescence mechanism is dominant when reheated at 595 °C and Ostwald ripening mechanism is dominant when reheated at 615 °C in the semi-solid state. A lower coarsening rate is observed for 615 °C(coarsening rate K = 391 μm3 s-1) compared with the coarsening rate for 595 °C(coarsening rate K = 501 μm3 s-1). The RAP 7075 aluminum alloy can be successfully thixoformed and the filling of components is good after thixoforming. The thixoformed components exhibit favorite mechanical properties.

关键词： 7075 High strength aluminum alloy Spheroidal micro

Spectral Fittings of Warm Coronal Radiation with High Seed Photon Temperature:Apparent Low-temperature and Flat Soft Excess in AGNs

在线全文

学校读者我要写书评

暂无评论

Research in Astronomy and Astrophysics 2024年第7期24卷 135-144页

作者： ze-Yuan tang jun-Jie Feng jun-Hui Fan School of Mathematics and Information Science Guangzhou UniversityGuangzhou 510006China Center for Astrophysics Guangzhou UniversityGuangzhou 510006China Astronomy Science and Technology Research Laboratory of Department of Education of Guangdong Province Guangzhou 510006China Key Laboratory for Astronomical Observation and Technology of Guangzhou Guangzhou 510006China

A warm corona has been widely proposed to explain the soft excess(SE)in X-ray above the 2-10 ke V power law extrapolation in Active Galactic Nuclei(AGNs).In actual spectral fittings,the warm coronal seed photon temperature(T_s)is usually assumed to be far away from the soft X-ray,but kT_scan reach close to 0.1 ke V in the standard accretion disk *** this study,we used Monte Carlo simulations to obtain radiation spectra from a slab-like warm corona and fitted the spectra using the spherical-geometry-based routine THCOMP or a thermal *** findings reveal tha high T_scan influence the fitting results.A moderately high kT_s(around 0.03 ke V)can result in an apparent low-temperature and flat SE,while an extremely high kT_s(around 0.07 ke V)can even produce an unobserved blackbody-like *** conclusions indicate that,for spectral fittings of the warm coronal radiation(SE in AGNs),kT_sshould be treated as a free parameter with an upper limit,and an accurate coronal geometry is necessary when kT_s>0.01 ke V.

关键词： galaxies active-accretion-accretion disks-black hole physics

Investigation on UV-curing Reprocessable Thermosets Bearing Hindered Urea Bonds and Their Composites with Modified Zinc Oxide Nanoparticles

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Polymer Science 2024年第6期42卷 751-765页

作者： jun-Hao Zhou Li-Ming tang Key Laboratory of Advanced Materials of Ministry of Education of China Department of Chemical EngineeringTsinghua UniversityBeijing100084China

In this study,a series of hindered urea bond(HUB)containing polyurethane-urea methacrylate prepolymers and a none HUB containing polyurethane methacrylate prepolymer were prepared using isobornyl methacrylate as the reactive diluent via one-pot *** prepolymers were characterized fully by various ***,their thermosets were fabricated via UV curing in presence of a photo initiator,and their mechanical property and thermal behavior were investigated and *** from the none HUB containing thermoset,the HUB containing thermosets(defined as PUT)could be recycled and reprocessed by hot press under relatively mild conditions with high recovery ratio of mechanical ***,zinc oxide(ZnO)nanoparticles were modified with 3-(trimethoxysilyl)propyl methacrylate and the modified ZnO(defined as ZnO-TPM)was dispersed and polymerized into PUT matrix to prepare their *** influence of ZnO-TPM on the mechanical performance of the composites was evaluated,which indicated that the Young’s modulus and tensile strength increased gradually to the maximum values at ZnO-TPM content of 1 wt%and then *** composites also displayed good reprocessability with improved recovery ratio compared to the pure PUT *** addition,the composite materials exhibited strong UV absorption capacity,implying their potential application in the circumstance where UV-shielding was required.

关键词： Polyurethane-urea methacrylate Hindered urea bond ZnO nanoparticles Reprocessing UV curing

Suppression of low-frequency ultrasound broadband vibration using star-shaped single-phase metamaterials

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4期34卷 217-224页

作者： Rui Zhao Jian Zheng Jin Guo Yunbo Shi Hengzhen Feng jun tang jun Liu Science and Technology on Electronic Test&Measurement Laboratory North University of ChinaTaiyuan 030051ShanxiChina School of Mechatronical Engineering Beijing Institute of TechnologyBeijing 100081China

In order to suppress the low-frequency ultrasound vibration in the broadband range of 20 k Hz—100 k Hz,this paper proposes and discusses an acoustic metamaterial with low-frequency ultrasound vibration attenuation properties,which is configured by hybrid arc and sharp-angle convergent star-shaped *** effect of the dispersion relation and the bandgap characteristic for the scatterers in star-shaped are simulated and *** target bandgap width is extended by optimizing the geometry parameters of arc and sharp-angle convergent *** proposed metamaterial configured by optimized hybrid lattices exhibits remarkable broad bandgap characteristics by bandgap complementarity,and the simulation results verify a 99%vibration attenuation amplitude can be obtained in the frequency of20 k Hz—100 k *** the fabrication of the proposed hybrid configurational star-shaped metamaterial by 3D printing technique,the transmission loss experiments are performed,and the experimental results indicate that the fabricated metamaterial has the characteristics of broadband vibration attenuation and an amplitude greater than 85%attenuation for the target *** results demonstrate that the hybrid configurational star-shaped metamaterials can effectively widen the bandgap and realize high efficiency attenuation,which has capability for the vibration attenuation in the application of highprecise equipment.

关键词： Star-shaped metamaterials Broadband Vibration attenuation Low-frequency ultrasound vibration Transmission loss

Changes in muscle strength and risk of cardiovascular disease among middle-aged and older adults in China:Evidence from a prospective cohort study

在线全文

学校读者我要写书评

暂无评论

Chinese Medical Journal 2024年第11期137卷 1343-1350页

作者： ze Yang Jiemin Wei Hongbo Liu Honglu Zhang Ruifang Liu Naijun tang Xueli Yang Department of Occupational and Environmental Health School of Public HealthTianjin Medical UniversityTianjin 300070China Tianjin Key Laboratory of Environment Nutrition and Public HealthTianjin Medical UniversityTianjin 300070China Center for International Collaborative Research on Environment Nutrition and Public HealthTianjin 300070China

Background:Evidence indicates that low muscle strength is associated with an increased cardiovascular diseases(CVDs)***,the association between muscle strength changes based on repeated measurements and CVD incidence remains ***:The study used data from the China Health and Retirement Longitudinal Study in 2011(Wave 1),2013(Wave 2),2015(Wave 3),and 2018(Wave 4).Low muscle strength was defined as handgrip strengthzed into four groups of Normal-Normal,Low-Normal,Normal-Low,and *** events,including heart disease and stroke,were recorded using a self-reported questionnaire during Waves 3 and 4 *** proportional hazards models were used to investigate the association between muscle strength changes and CVD incidence after multivariable *** ratios(HRs)and 95%confidence intervals(95%CIs)were estimated with the Normal-Normal group as the ***:A total of 1164 CVD cases were identified among 6608 *** to participants with sustained normal muscle strength,the CVD risks increased progressively across groups of the Low-Normal(HR=1.20,95%CI:1.01-1.43),the Normal-Low(HR=1.35,95%CI:1.14-1.60),and the Low-Low(HR=1.76,95%CI:1.49-2.07).Similar patterns were observed for the significant associations between muscle strength status and the incidence risks of heart disease and *** analyses showed that the significant associations between CVD and muscle strength changes were consistent across age,sex,and body mass index(BMI)***:The study found that muscle strength changes were associated with CVD *** suggests that continuous tracking of muscle status may be helpful in screening cardiovascular risk.

关键词： Muscle strength Cardiovascular disease Prospective cohort study Aging Body mass index Sarcopenia

A deep multimodal fusion and multitasking trajectory prediction model for typhoon trajectory prediction to reduce flight scheduling cancellation

在线全文

学校读者我要写书评

暂无评论

Journal of Systems Engineering and Electronics 2024年第3期35卷 666-678页

作者： tang jun QIN Wanting PAN Qingtao LAO Songyang College of Systems Engineering National University of Defense TechnologyChangsha 410000China

Natural events have had a significant impact on overall flight activity,and the aviation industry plays a vital role in helping society cope with the impact of these *** one of the most impactful weather typhoon seasons appears and continues,airlines operating in threatened areas and passengers having travel plans during this time period will pay close attention to the development of tropical *** paper proposes a deep multimodal fusion and multitasking trajectory prediction model that can improve the reliability of typhoon trajectory prediction and reduce the quantity of flight scheduling *** deep multimodal fusion module is formed by deep fusion of the feature output by multiple submodal fusion modules,and the multitask generation module uses longitude and latitude as two related tasks for simultaneous *** more dependable data accuracy,problems can be analysed rapidly and more efficiently,enabling better decision-making with a proactive versus reactive *** multiple modalities coexist,features can be extracted from them simultaneously to supplement each other’s *** actual case study,the typhoon Lichma that swept China in 2019,has demonstrated that the algorithm can effectively reduce the number of unnecessary flight cancellations compared to existing flight scheduling and assist the new generation of flight scheduling systems under extreme weather.

关键词： flight scheduling optimization deep multimodal fusion multitasking trajectory prediction typhoon weather flight cancellation prediction reliability

Visualisation and Heat Transfer Performance of Mini-Channel Flat Heat Pipe with a Binary Mixture

在线全文

学校读者我要写书评

暂无评论

Journal of Thermal Science 2024年第5期33卷 1712-1725页

作者： FAN Gaoting tang Aikun CAI Tao SHAN Chunxian PAN jun JIN Yi School of Energy and Power Engineering Jiangsu UniversityZhenjiang 212013China Jiangsu Jinhe Energy Technology Co.Ltd Zhenjiang 212400China

To unravel the intricacies of two-phase gas-liquid flow characteristics and heat transfer behavior,an array mini-channel gravity plate heat pipe(AMGPHP)is proposed in this work,which allows for observing the internal changes in the state of the working *** flow patterns such as pool flow,columnar flow,and slug flow,are experimentally explored and analyzed in *** is found that the optimal volume fill ratio is 20%by utilizing start-up time and thermal resistance as performance evaluation *** this fill ratio,a medium optimization strategy by blending ethanol within R141b is proposed and *** comparison to pure working fluids,the heat transfer performance of AMGFHP in the binary fluid has been significantly augmented due to temperature and concentration shifts resulting from disparate boiling *** the 10%volume fraction ethanol blending condition,the equivalent thermal conductivity of the heat pipe is dramatically elevated,with a value of 3110 W/(m·℃),along with the reduction of the minimum start-up power to 4 *** general,applying such a medium to heat pipes has considerable potential in practical applications.

关键词： flat heat pipe mini-channel visualisation two-phase flow binary mixtures thermal performance

Efficacy and safety of Chinese herbal medicine as adjunctive therapy in sepsis patients with bloodstream infection:a propensity-matched analysis

在线全文

学校读者我要写书评

暂无评论

Journal of Traditional Chinese Medicine 2024年第1期44卷 197-204页

作者： ZHOU Xianshi ZHONG Minlin XI Xiaotu LI jun tang Guanghua the Second Clinical College of Guangzhou University of Chinese Medicine Guangzhou 510120China Emergency Department Guangdong Provincial Hospital of Chinese MedicineGuangzhou 510120China Guangdong Provincial Key Laboratory of Research on Emergency in TCM Guangzhou 510120China Guangzhou Key Laboratory of Traditional Chinese Medicine for Prevention and Treatment of Emerging Infectious Diseases Guangzhou 510120China Administration Department the First Hospital of Guangzhou University of Chinese MedicineGuangzhou 510405China

OBJECTIVE:To investigate the efficacy and safety of Chinese herbal medicine in treating sepsis patients with bloodstream ***:A 6-year retrospective study was carried out at a university hospital in *** sepsis patients with bloodstream infection were *** primary outcome was 28-day mortality after *** score method was used to adjust for possible confounding.28-day mortality was estimated by KaplanMeier analysis and compared using the log-rank *** regression analysis was carried out to identify factors impacting in-hospital mortality ***:Following the application of the propensity score method,a total of 176 patients were *** all-cause 28-day mortality in the control group and Chinese herbal medicine group was 21.6%and 14.8%,***-Meier survival analysis showed that Chinese herbal medicine was associated with a lower hazard ratio(HR)in all-cause 28-day death compared with the control group[HR=0.44,95%CI(0.22,0.90),P0.05).Blood-activating and stasis-eliminating herb administration was associated with reduced inhospital mortality among sepsis patients with bloodstream infection[HR=0.54,95%CI(0.34,0.94),P<0.05].CONCLUSIONS:Chinese herbal medicine,especially the blood-activating and stasis-eliminating herb,might have certain efficacy and safety in treating sepsis patients with bloodstream *** should prescribe blood-activating and stasis-eliminating herb in treating these two coalescent critical diseases as long as no contraindications ***,further studies are needed to validate our results.

关键词： bacteremia medicine Chinese traditional herbal medicine sepsis propensity-matched analysis

Characterization of the current crowding effect on chip surface using a quantum wide-field microscope

在线全文

学校读者我要写书评

暂无评论

Chinese Optics Letters 2024年第6期22卷 123-128页

作者： Rui Zhao Ding Wang Huan Fei Wen Yunbo Shi jun tang jun Liu Science and Technology on Electronic Test&Measurement Laboratory North University of ChinaTaiyuan 030051China

We characterize the current crowding effect for microwave radiation on a chip surface based on a quantum wide-field microscope combining a wide-field reconstruction technique. A swept microwave signal with the power of 0–30 d Bm is supplied to a dumbbell-shaped microstrip antenna, and the significant differences in microwave magnetic-field amplitudes attributed to the current crowding effect are experimentally observed in a 2.20 mm ×1.22 mm imaging area. The normalized microwave magnetic-field amplitude along the horizontal geometrical center of the image area further demonstrates the feasibility of the characterization of the current crowding effect. The experiments indicate the proposal can be qualified for the characterization of the anomalous area of the radio-frequency chip surface.

关键词： current crowding effect microwave field on chip surface quantum wide-field microscope nitrogen-vacancy center