Microstructure characteristics and corrosion behavior of metal inert gas welded dissimilar joints of 6005A modified by Sc and 5083 alloys

The corrosion behavior and microstructure characteristics of metal inert gas(MIG)welded dissimilar joints of the 6005A alloy modified with Sc(designated as 6005A+Sc)and the 5083 alloy were investigated using corrosion tests and microscopy techniques.Results show that the dissimilar joints exhibit strong stress corrosion cracking(SCC)resistance,maintaining substantial strength during slow strain rate tensile tests.Notably,the heat-affected zone(HAZ)and base metal(BM)on the 6005A+Sc side show superior performance in terms of inter-granular corrosion(IGC)and exfoliation corrosion(EXCO)compared to the corresponding zones on the 5083 side.The lower corrosion resistance of the 5083-BM and the 5083-HAZ can be attributed to the presence of numerous Al_(2)Mg_(3)phases and micro-scaled Al_(6)(Mn,Fe)intermetallics,mainly distributed along the rolling direction.Conversely,the enhanced corrosion resistance of the 6005A+Sc-BM and the 6005A+Sc-HAZ can be attributed to the discontinuously distributed grain boundary precipitates(β-Mg_(2)Si),the smaller grain size,and the reduced corrosive current density.

Bi-directional interaction of joint shear strength in non-seismically designed corner RC beam-column connections under seismic loading

Non-seismically designed(NSD)beam-column joints are susceptible to joint shear failure under seismic loads.Although significant research is available on the seismic behavior of such joints of planar frames,the information on the seismic behavior of joints of space frames(3D joints)is insufficient.The 3D joints are subjected to bi-directional excitation,which results in an interaction between the shear strength obtained for the joint in the two orthogonal directions separately.The bi-directional seismic behavior of corner reinforced concrete(RC)joints is the focus of this study.First,a detailed finite element(FE)model using the FE software Abaqus,is developed and validated using the test results from the literature.The validated modeling procedure is used to conduct a parametric study to investigate the influence of different parameters such as concrete strength,dimensions of main and transverse beams framing into the joint,presence or absence of a slab,axial load ratio and loading direction on the seismic behavior of joints.By subjecting the models to different combinations of loads on the beams along perpendicular directions,the interaction of the joint shear strength in two orthogonal directions is studied.The comparison of the interaction curves of the joints obtained from the numerical study with a quadratic(circular)interaction curve indicates that in a majority of cases,the quadratic interaction model can represent the strength interaction diagrams of RC beam to column connections with governing joint shear failure reasonably well.

Joint Retrieval of PM_(2.5) Concentration and Aerosol Optical Depth over China Using Multi-Task Learning on FY-4A AGRI

Aerosol optical depth(AOD)and fine particulate matter with a diameter of less than or equal to 2.5μm(PM_(2.5))play crucial roles in air quality,human health,and climate change.However,the complex correlation of AOD–PM_(2.5)and the limitations of existing algorithms pose a significant challenge in realizing the accurate joint retrieval of these two parameters at the same location.On this point,a multi-task learning(MTL)model,which enables the joint retrieval of PM_(2.5)concentration and AOD,is proposed and applied on the top-of-the-atmosphere reflectance data gathered by the Fengyun-4A Advanced Geosynchronous Radiation Imager(FY-4A AGRI),and compared to that of two single-task learning models—namely,Random Forest(RF)and Deep Neural Network(DNN).Specifically,MTL achieves a coefficient of determination(R^(2))of 0.88 and a root-mean-square error(RMSE)of 0.10 in AOD retrieval.In comparison to RF,the R^(2)increases by 0.04,the RMSE decreases by 0.02,and the percentage of retrieval results falling within the expected error range(Within-EE)rises by 5.55%.The R^(2)and RMSE of PM_(2.5)retrieval by MTL are 0.84 and 13.76μg m~(-3)respectively.Compared with RF,the R^(2)increases by 0.06,the RMSE decreases by 4.55μg m~(-3),and the Within-EE increases by 7.28%.Additionally,compared to DNN,MTL shows an increase of 0.01 in R^(2)and a decrease of 0.02 in RMSE in AOD retrieval,with a corresponding increase of 2.89%in Within-EE.For PM_(2.5)retrieval,MTL exhibits an increase of 0.05 in R^(2),a decrease of 1.76μg m~(-3)in RMSE,and an increase of 6.83%in Within-EE.The evaluation suggests that MTL is able to provide simultaneously improved AOD and PM_(2.5)retrievals,demonstrating a significant advantage in efficiently capturing the spatial distribution of PM_(2.5)concentration and AOD.

The Matrix Stiffness and Physical Confinement of Hydrogel Microchannel Jointly Induce the Mesenchymal-Amoeboid Transition for Cancer Cell Migration

The migration mode transition of cancer cell enhances its invasive capability and the drug resistance,where physical confinement of cell microenvironment has been revealed to induce the mesenchymal-amoeboid transition(MAT).However,most existing studies are performed in PDMS microchannels,of which the stiffness is much higher than that of most mammalian tissues.Therefore,the amoeboid migration transition observed in these studies is actually induced by the synergistic effect of matrix stiffness and confinement.Since the stiffness of cell microenvironment has been reported to influence the cell migration in 2D substrate,the decoupling of stiffness and confinement effects is thus in need for elucidating the underlying mechanism of MAT.However,it is technically challenging to construct microchannels with physiologically relevant stiffness and channel size,where existing microchannel platforms with physiological relevance stiffness are all with>10μm channel width.Such size is too wide to mimic the physical confinement that migrating cancer cells confront in vivo,and also larger than the width of PDMS channel,in which the MAT of cancer cell was observed.Therefore,an in vitro cell migration platform,which could mimic both stiffness and confinement of the native physical microenvironment during cancer metastasis,could profoundly contribute to researches on cancer cell migration and cellular mechanotransduction.In this paper,we overcome the limitations of engineering soft materials in microscale by combining the collagen-alginate hydrogel with photolithography.This enables us to improve the accuracy of molded microchannel,and thus successfully construct a 3D microchannel platform,which matches the stiffness and width ranges of native environmental confinement that migrating cancer cells confront in vivo.The stiffness(0.3~20 kPa),confinement(channel width:3.5~14μm)and the adhesion ligand density of the microchannel can be tuned independently.Interestingly,using this platform,we observed that the migration speed of cancer cell is influenced by the synergistic effect of channel stiffness and width,and the increasing stiffness reverses the effect of channel width on the migration speed of cancer cells.In addition,MAT has a strong correlation with the channel stiffness.These findings make us reconsider the widely accepted hypothesis:physical confinement can induce MAT.Actually,this transition can only occur in stiff confined microenvironment not in soft one.For soft microchannels,the compliance of the channel walls could cause little cell/nucleus deformation,and the MAT could not be induced.To further investigate the mechanism of MAT,we developed a computational model to simulate the effect of nucleus deformation on MAT.With the model,we found that deforming the cell nuclear by decreasing the nucleus stiffness will reduce the cellmigration speed.This implies that nuclear stiffness plays an important role in the regulation of cancer migration speed and thus MAT in microchannels.The effect of channel stiffness on MAT and migration speed as observed in our experiment could partially explain previous findings reported in the literature,where the increasing matrix stiffness of tumor microenvironment promotes cancer metastasis.Our observations thus highlight the critical role of cell nuclear deformation not only in MAT,but also in regulating cellular mechanotransduction and cell-ECM interactions.This developed platform is capable of mimicking the native physical microenvironment during metastasis,providing a powerful tool for high-throughput screening applications and investigating the interaction between cancer migration and biophysical microenvironment.

Root nutrient capture and leaf resorption efficiency modulated by different influential factors jointly alleviated P limitation in Quercus acutissima across the North–South Transect of Eastern China

Soil and climatic conditions are known to have close associations with plant morphological and stoichiometric traits at a regional scale along latitudinal gradients;however,how latitude drives biotic and abiotic factors affecting plant nutrient acquisition to accommodate environmental nutrient deficiency remains unclear.We quantified soil,root,leaf,and leaf litter nitrogen(N)and phosphorus(P)concentrations to determine the potentially limiting nutrient and the simultaneous responses of root capture and leaf resorption to nutrient deficiency in seven Quercus acutissima forests across the North–South Transect of Eastern China.The results showed that the mean leaf and root N:P ratios in Q.acutissima were 21.58 and 20.23,respectively,which markedly exceeded the P limitation threshold of 16 for terrestrial plants.The mean leaf litter N and P were 10.63 mg/g and 0.51 mg/g,respectively,indicating that P resorption proficiency was relatively higher than N resorption proficiency.N displayed higher stoichiometric homeostasis than P in the leaf.The leaf and root N:P ratios showed a quadratic variation that first decreased and then increased as latitude increased,whereas the phosphorus resorption efficiency and root-soil accumulation factor of P displayed the opposite trend.Partial least square path modeling(PLS-PM)analysis demonstrated that root nutrient capture and leaf nutrient resorption were regulated by different influential factors.Overall,these findings provide new insights into plant strategies to adapt to environmental nutrient deficiency,as well as the scientific basis for predicting the spatial and temporal patterns of nutrient acquisition in the context of climate change.

Catalytic System for Manufacturing Butanol via Hydroformylation of Low-Carbon Olefins Developed Jointly by CNOOC and Others

Recently,the project“Development and application of low-temperature and high-selectivity catalytic system for hydroformylation of low-carbon olefins”jointly undertaken by the China National Offshore Oil Company(CNOOC)Group,the CNOOC Refining and Chemical Research Institute(Beijing),the CNOOC Tianjin Chemical Engineering and Design Institute,the Shenhua Baotou Coal Chemical Engineering Company,and the Yan’an Energy Chemical Company.

A statistical damage-based constitutive model for shearing of rock joints in brittle drop mode

Some rock joints exhibit significant brittleness,characterized by a sharp decrease in shear stress upon reaching the peak strength.However,existing models often fail to accurately represent this behavior and are encumbered by numerous parameters lacking clear mechanical significance.This study presents a new statistical damage constitutive model rooted in both damage mechanics and statistics,containing only three model parameters.The proposed model encompasses all stages of joint shearing,including the compaction stage,linear stage,plastic yielding stage,drop stage,strain softening stage,and residual strength stage.To derive the analytical expression of the constitutive model,three boundary conditions are introduced.Experimental data from both natural and artificial rock joints is utilized to validate the model,resulting in average absolute relative errors ranging from 3%to 8%.Moreover,a comparative analysis with established models illustrates that the proposed model captures stress drop and post-peak strain softening more effectively,with model parameters possessing clearer mechanical interpretations.Furthermore,parameter analysis is conducted to investigate the impacts of model parameters on the curves and unveil the relationship between these parameters and the mechanical properties of rock joints.Importantly,the proposed model is straightforward in form,and all model parameters can be obtained from direct shear tests,thus facilitating the utilization in numerical simulations.

Blood metal concentrations and cardiac structure and function in total joint arthroplasty patients

BACKGROUND There is concern regarding potential long-term cardiotoxicity with systemic distribution of metals in total joint arthroplasty(TJA)patients.AIM To determine the association of commonly used implant metals with echocardiographic measures in TJA patients.METHODS The study comprised 110 TJA patients who had a recent history of high chromium,cobalt or titanium concentrations.Patients underwent two-dimensional,three-dimensional,Doppler and speckle-strain transthoracic echocardiography and a blood draw to measure metal concentrations.Age and sex-adjusted linear and logistic regression models were used to examine the association of metal concentrations(exposure)with echocardiographic measures(outcome).RESULTS Higher cobalt concentrations were associated with increased left ventricular end-diastolic volume(estimate 5.09;95%CI:0.02-10.17)as well as left atrial and right ventricular dilation,particularly in men but no changes in cardiac function.Higher titanium concentrations were associated with a reduction in left ventricle global longitudinal strain(estimate 0.38;95%CI:0.70 to 0.06)and cardiac index(estimate 0.08;95%CI,-0.15 to-0.01).CONCLUSION Elevated cobalt and titanium concentrations may be associated with structural and functional cardiac changes in some patients.Longitudinal studies are warranted to better understand the systemic effects of metals in TJA patients.

Cyclic shear behavior of en-echelon joints under constant normal stiffness conditions

To reveal the mechanism of shear failure of en-echelon joints under cyclic loading,such as during earthquakes,we conducted a series of cyclic shear tests of en-echelon joints under constant normal stiffness(CNS)conditions.We analyzed the evolution of shear stress,normal stress,stress path,dilatancy characteristics,and friction coefficient and revealed the failure mechanisms of en-echelon joints at different angles.The results show that the cyclic shear behavior of the en-echelon joints is closely related to the joint angle,with the shear strength at a positive angle exceeding that at a negative angle during shear cycles.As the number of cycles increases,the shear strength decreases rapidly,and the difference between the varying angles gradually decreases.Dilation occurs in the early shear cycles(1 and 2),while contraction is the main feature in later cycles(310).The friction coefficient decreases with the number of cycles and exhibits a more significant sensitivity to joint angles than shear cycles.The joint angle determines the asperities on the rupture surfaces and the block size,and thus determines the subsequent shear failure mode(block crushing and asperity degradation).At positive angles,block size is more greater and asperities on the rupture surface are smaller than at nonpositive angles.Therefore,the cyclic shear behavior is controlled by block crushing at positive angles and asperity degradation at negative angles.

Experimental and simulation research on hollow AZ31 magnesium alloy three-channel joint by hot extrusion forming with sand mandrel

Magnesium alloy is one of the lightest metal structural materials.The weight is further reduced through the hollow structure.However,the hollow structure is easily damaged during processing.In order to maintain the hollow structure and to transfer the stresses during the high temperature deformation,the sand mandrel is proposed.In this paper,the hollow AZ31 magnesium alloy three-channel joint is studied by hot extrusion forming.Sand as one of solid granule medium is used to fill the hollow magnesium alloy.The extrusion temperatures are 230℃ and 300℃,respectively.The process parameters(die angle,temperature,bottom thickness,sidewall thickness,edge-to-middle ratio in bottom,bottom shape)of the hollow magnesium alloy are analyzed based on the results of experiments and the finite element method.The results are shown that the formability of the hollow magnesium alloy will be much better when the ratio of sidewall thickness to the bottom thickness is 1:1.5.Also when edge-to-middle ratio in bottom is about 1:1.5,a better forming product can be received.The best bottom shape in these experiments will be convex based on the forming results.The grain will be refined obviously after the extrusion.Also the microstructures will be shown as streamlines.And these lines will be well agreement with the mold in the corner.

Technical Patents for Artificial Intelligence Are Growing Rapidly——The Hurun Research Institute and WTOIP jointly released AI Intellectual Property in China 2019

Recently,the Hurun Research Institute and WTOIP jointly released AI Intellectual Property in China 2019,which shows that in the last five years the global figure of artificial intelligence(AI)patent applications grew rapidly,and were led by China,especially in the fields of vision,robotics and language.

Symposium on Xi Jinping Thought on Diplomacy Jointly Held by Chinese and Korean Think Tanks

On July 23,Xi Jinping Thought on Diplomacy Studies Center and the ROK's Sungkyun Institute of China Studies jointly held a seminar on"A Community with a Shared Future for Mankind and Xi Jinping Thought on Diplomacy."

China and Central Asian Countries Jointly Building the Digital Silk Road:Foundations,Challenges and Paths

In recent years,Central Asian countries have generally adopted the digital economy as a new impetus and new direction for building a modern economic system and promoting the high-quality development of their economies,and have been actively conducting relevant international cooperation.Since Chinese President Xi Jinping advocated the joint construction of the Digital Silk Road at the first Belt and Road Forum for International Cooperation,Central Asian countries have responded positively.Cooperation in the digital economy is likely to become the most promising new area for China and Central Asian countries to jointly build the Silk Road Economic Belt and improve the level of regional economic development.Therefore,in order to better promote bilateral cooperation,it is necessary to carry out an in-depth discussion on the foundations of cooperation as well as challenges which China and the Central Asian countries face when jointly building the Digital Silk Road.

China Society for Human Rights Studies(CSHRS)and Sapienza University of Rome Jointly Hold 2023 China-Europe Seminar on Human Rights

On September 20th,the 2023 China-Europe Seminar on Human Rights was held jointly by China Society for Human Rights Studies(CSHRS)and Sapienza University of Rome in Rome,Italy.The seminar,themed"Modernisation and the Diversity of Human Rights Among Civilisations"was attended by more than 130 human rights experts,government officials,members of parliament and representatives from political parties and social organisations from China,Italy,Greece,the United Kingdom,the United States,Germany,Netherlands,Spain,Switzerland,Austria,Bulgaria,Czech Republic,Norway,Poland,Portugal,Serbia and other countries through both online and offline channels.

Chinese and Serbian Friends Jointly Celebrating the Chinese New Year's Eve

This year marks the fifth year for China and Serbia to jointly celebrate the Chinese New Year,and the celebration is to be extended to other cities apart from Belgrade,Serbia,which shows the sincere friendship between the two peoples and the Serbian people's love for the Chinese people and Chinese culture.

Chinese Association for International Understanding and the Friedrich-Ebert-Stiftung Jointly Hold a Webinar

On January 13th,the Chinese Association for International Understanding(CAFIU)and the Friedrich-Ebert-Stiftung(FES)jointly held a Webinar themed Promoting People-to-People and Cultural Exchanges and Mutual Learning among Civilisations,Enhancing Mutual Understanding and Friendship between China and Germany.

Method for the Determination of Sudan Dyes in Foods-High Performance Liquid Chromatography Jointly Issued by AQSIQ and SAC

Sudan Red are the chemosynthesis dyes of series of azo, which are mainly used as coloring additives in ma- nufacturing of some products, such as the wax, the oil-dyes, the petrol, and etc. In the process of food production, Sudan Dyes are banned to be used as food dyes in our country.

Analysis of the joint detection capability of the SMILE satellite and EISCAT-3D radar

The Solar wind Magnetosphere Ionosphere Link Explorer(SMILE)satellite is a small magnetosphere–ionosphere link explorer developed cooperatively between China and Europe.It pioneers the use of X-ray imaging technology to perform large-scale imaging of the Earth’s magnetosheath and polar cusp regions.It uses a high-precision ultraviolet imager to image the overall configuration of the aurora and monitor changes in the source of solar wind in real time,using in situ detection instruments to improve human understanding of the relationship between solar activity and changes in the Earth’s magnetic field.The SMILE satellite is scheduled to launch in 2025.The European Incoherent Scatter Sciences Association(EISCAT)-3D radar is a new generation of European incoherent scatter radar constructed by EISCAT and is the most advanced ground-based ionospheric experimental device in the high-latitude polar region.It has multibeam and multidirectional quasi-real-time three-dimensional(3D)imaging capabilities,continuous monitoring and operation capabilities,and multiple-baseline interferometry capabilities.Joint detection by the SMILE satellite and the EISCAT-3D radar is of great significance for revealing the coupling process of the solar wind–magnetosphere–ionosphere.Therefore,we performed an analysis of the joint detection capability of the SMILE satellite and EISCAT-3D,analyzed the period during which the two can perform joint detection,and defined the key scientific problems that can be solved by joint detection.In addition,we developed Web-based software to search for and visualize the joint detection period of the SMILE satellite and EISCAT-3D radar,which lays the foundation for subsequent joint detection experiments and scientific research.

Jointly Build the Belt and Road Initiative with a Two-Wheel Drive——International Work of The Amity Foundation

With the development of economy and society,China’s comprehensive national strength has been continuously enhanced and its international influence has been increasing.China is shouldering more international responsibilities and obligations to make greater contributions to building a community of shared future for mankind by“always being a builder of world peace,a contributor to global development,and a defender of the international order”.In March 2015,President Xi Jinping put forward the concept of the Belt and Road Initiative,which not only pointed out the way for Chinese social organizations to participate in international affairs,but also opened up unprecedented opportunities for Chinese social organizations to further participate in global governance.

A photogrammetric approach for quantifying the evolution of rock joint void geometry under varying contact states

Accurate measurement of the evolution of rock joint void geometry is essential for comprehending the distribution characteristics of asperities responsible for shear and seepage behaviors.However,existing techniques often require specialized equipment and skilled operators,posing practical challenges.In this study,a cost-effective photogrammetric approach is proposed.Particularly,local coordinate systems are established to facilitate the alignment and precise quantification of the relative position between two halves of a rock joint.Push/pull tests are conducted on rock joints with varying roughness levels to induce different contact states.A high-precision laser scanner serves as a benchmark for evaluating the photogrammetry method.Despite certain deviations exist,the measured evolution of void geometry is generally consistent with the qualitative findings of previous studies.The photogrammetric measurements yield comparable accuracy to laser scanning,with maximum errors of 13.2%for aperture and 14.4%for void volume.Most joint matching coefficient(JMC)measurement errors are below 20%.Larger measurement errors occur primarily in highly mismatched rock joints with JMC values below 0.2,but even in cases where measurement errors exceed 80%,the maximum JMC error is only 0.0434.Thus,the proposed photogrammetric approach holds promise for widespread application in void geometry measurements in rock joints.