Bemisia tabaci is a polyphagous herbivore that feeds on a wide range of horticultural and ornamental crops cultivated under diverse ecological zones. In Sierra Leone, B. tabaci is found to infest a wide range of veget...Bemisia tabaci is a polyphagous herbivore that feeds on a wide range of horticultural and ornamental crops cultivated under diverse ecological zones. In Sierra Leone, B. tabaci is found to infest a wide range of vegetable crops by directly feeding on phloem sap thereby inducing physiological disorders, and also serve as a vector to gemini viruses. Invariably the destructive feeding of B. tabaci affects the productivity and aesthetic values of vegetables and other horticultural crops and hence is considered a serious economic pest. A bioassay experiment was carried out by rearing B. tabaci populations on four vegetable crops under controlled laboratory conditions to determine its life table and demographic parameters. Results showed that the intrinsic rate of growth which measures the population size and growth pattern was highest for populations reared on tomato crops with the following values: rm 0.145 female female−1 day−1, the gross reproduction rate (Ro), and finite growth rate λ were highest for population reared on tomato, correspondingly the development period from egg-adult emergence was shortest with a value of 26 d. Conversely, the computed demographical parameters rm, λ and Ro for the population reared on sweet pepper were 0.106 female female−1 day−1 respectively, with a corresponding development period egg-adult emergence as 36d. The computed biological parameters for okra and garden egg varied with intermediary values between tomato and pepper host materials. The survivorship rates were quite significant for the smaller instars (Instars 1-III) with over 80% surviving to pre-pupa and pupa stage for the populations reared for all the test materials. High mortality was noticed for the pre-pupa and pupa stages as their survival rates were significantly low compared to the high survival rates of the smaller instars. Less than 50% of pupae failed to emerge to adults except for populations reared on tomato test materials where 52% emerged to adults. The study indicated tomato as the most suitable host among the four vegetable crops. Although life table and demographic parameters are invaluable information for forecasting pest populations and help in designing pest management efforts, further investigations such as the economic threshold and economic injury levels of B. tabaci population are requisite decision tools for sound pest management decisions of B. tabaci on these vegetable crops. The information obtained from this investigation would be quite relevant for extension service and pest management practitioners where mixed vegetable farming is a common practice.展开更多
On April 19th,"the Youth Table Tennis Programme—Photo Exhibition of Zhou Enlai and the Bandung Conference&China-ASEAN(Indonesia)Youth Table Tennis Training Camp"opened in Jakarta,Indonesia.The event was...On April 19th,"the Youth Table Tennis Programme—Photo Exhibition of Zhou Enlai and the Bandung Conference&China-ASEAN(Indonesia)Youth Table Tennis Training Camp"opened in Jakarta,Indonesia.The event was guided by the Chinese Embassy in Indonesia and co-organised by the ASEAN-China Centre(ACC),the Memorial to Zhou Enlai and Deng Yingchao,the China Friendship Foundation for Peace and Development,the Beijing One Heart Sphere Charity Foundation,and the Enlai Foundation.展开更多
Table manners are important in manycultures.Inmost countries,youwait untileveryone has food before eating.Youalso don't put your elbows on the table.It's not polite to eat too fast.And youshouldn't talk wi...Table manners are important in manycultures.Inmost countries,youwait untileveryone has food before eating.Youalso don't put your elbows on the table.It's not polite to eat too fast.And youshouldn't talk with food in yourmouth orchew with your mouth open.展开更多
Weak interlayers play a crucial role in the seismic performance of bedding slopes;however,the effects of structural surface development within these layers remain underexplored.This study presents two scaled models of...Weak interlayers play a crucial role in the seismic performance of bedding slopes;however,the effects of structural surface development within these layers remain underexplored.This study presents two scaled models of bedding slopes,each with different weak interlayers:one with a homogeneous weak layer and another with discontinuous interfaces.Shaking table tests were conducted to compare their seismic performance.The results show that the peak ground acceleration(PGA)values above the weak interlayer in model A were significantly higher than those in model B,with the differences increasing as the input wave amplitude increased.The peak earth pressure(PEP)values at the tensile failure boundary at the rear edge of model A were also higher,whereas those within the weak layer at the toe of model A were lower than those in model B.Deformation analysis revealed that the maximum principal strain in model A initially appeared at the upper part of the tensile failure boundary,while the maximum shear strain was concentrated near the rear edge within the weak layer.In contrast,model B exhibited the opposite strain distribution.These findings provide insight into the impact of weak interlayers on the dynamic response and deformation of bedding slopes,highlighting the importance of considering this factor in seismic landslide investigations and failure mode predictions.展开更多
A fault is a geological structure characterized by significant displacement of rock masses along a fault plane within the Earth's crust.The Yunnan Tabaiyi Tunnel intersects multiple fault zones,making tunnel const...A fault is a geological structure characterized by significant displacement of rock masses along a fault plane within the Earth's crust.The Yunnan Tabaiyi Tunnel intersects multiple fault zones,making tunnel construction in fault-prone areas particularly vulnerable to the effects of fault activity due to the complexities of the surrounding geological environment.To investigate the dynamic response characteristics of tunnel structures under varying surrounding rock conditions,a three-dimensional large-scale shaking table physical model test was conducted.This study also aimed to explore the damage mechanisms associated with the Tabaiyi Tunnel under seismic loading.The results demonstrate that poor quality surrounding rock enhances the seismic response of the tunnel.This effect is primarily attributed to the distribution characteristics of acceleration,dynamic strain,and dynamic soil pressure.A comparison between unidirectional and multi-directional(including vertical)seismic motions reveals that vertical seismic motion has a more significant impact on specific tunnel locations.Specifically,the maximum tensile stress is observed at the arch shoulder,with values ranging from 60 to 100 k Pa.Moreover,NPR(Non-Prestressed Reinforced)anchor cables exhibit a substantial constant resistance effect under low-amplitude seismic waves.However,when the input earthquake amplitude reaches 0.8g,local sliding occurs at the arch shoulder region of the NPR anchor cable.These findings underscore the importance of focusing on seismic mitigation measures in fault zones and reinforcing critical areas,such as the arch shoulders,in practical engineering applications.展开更多
Seismic-induced landslides critically threaten infrastructure and human safety,especially in sandy slopes where conventional stabilization methods often fail under dynamic loading.This study evaluates circular open-en...Seismic-induced landslides critically threaten infrastructure and human safety,especially in sandy slopes where conventional stabilization methods often fail under dynamic loading.This study evaluates circular open-ended anti-slide pipe piles embedded in a two-layer sandy slope with differing geotechnical properties.Ten physical models,including five freefield and five pile-reinforced slopes,were tested on a shaking table.Key seismic responses—acceleration,soil displacement,and bending moments—were monitored using accelerometers,strain gauges,and Digital Image Correlation(DIC).Complementary numerical simulations using Abaqus with a Mohr–Coulomb model validated experimental results.Soil displacement in free-field models under 0.25g shaking was about 3.5 times greater than in reinforced slopes.Bending moments increased with seismic intensity,peaking at depths around five times the pile diameter.Limitations including simplified two-layer soil representation,idealized seismic inputs,and boundary effects inherent to laboratory models restrict direct field application but enable controlled analysis.By combining physical experiments with numerical modeling,the study provides a robust and validated framework for seismic slope stabilization.This integrated approach enhances understanding of soil–pile interaction under seismic loads and offers targeted insights for developing safer and more reliable geotechnical design strategies in earthquake-prone areas.展开更多
The relative stiffness between underground structures and surrounding soil may significantly influence the dynamic response of such structures.In this study,two underground pipelines were fabricated using rubber joint...The relative stiffness between underground structures and surrounding soil may significantly influence the dynamic response of such structures.In this study,two underground pipelines were fabricated using rubber joints with varying stiffness,and the corresponding dynamic response was evaluated.Model soils were prepared based on similarity ratios.Next,reduced-scale shaking table tests were conducted to investigate the impact of circular underground structures with varying stiffness joints on the amplification of ground acceleration,dynamic response,and deformation patterns of the underground pipelines.The comparative analysis showed that structures with lower stiffness exert less constraint on the surrounding soil,resulting in a higher amplification factor of ground acceleration.The seismic response of less stiff structures is generally 1.1 to 1.3 times the response of the stiffer structures.Therefore,the seismic response of the variable stiffness pipeline exhibits pronounced characteristics.Rubber joints effectively reduce the seismic response of underground structures,demonstrating favorable isolation effects.Consequently,relative stiffness plays a crucial role in the seismic design of underground structures,and the use of rubber materials in underground structures is advantageous.展开更多
In this study, shaking table tests were performed to investigate the dynamic characteristics of a mold transformer. Based on the test results, rotary friction dampers were developed to mitigate the excessive lateral d...In this study, shaking table tests were performed to investigate the dynamic characteristics of a mold transformer. Based on the test results, rotary friction dampers were developed to mitigate the excessive lateral displacement that occurred along the direction of the weak stiffness axis of the mold transformer. In addition, shaking table tests were performed by attaching friction dampers to both sides of the mold transformer. Based on the shaking table test results, the natural frequency, mode vector, and damping ratio of the mold transformer were derived using the transfer function and half-power bandwidth. The test results indicated that the use of friction dampers can decrease the displacement and acceleration response of the mold transformer. Finally, dynamic structural models were established considering the component connectivity and mass distribution of the mold transformer. In addition, a numerical strategy was proposed to calibrate the stiffness coefficients of the mold transformer, thereby facilitating the relationship between generalized mass and stiffness. The results indicated that the analytical model based on the calibration strategy of stiffness coefficients can reasonably simulate the dynamic behavior of the mold transformer using friction dampers with regard to transfer function, displacement, and acceleration response.展开更多
Transmission tower-line systems(TTLSs)play a crucial role in the long-distance transmission of electrical energy,often necessitating their crossing through active fault areas.However,previous studies have given limite...Transmission tower-line systems(TTLSs)play a crucial role in the long-distance transmission of electrical energy,often necessitating their crossing through active fault areas.However,previous studies have given limited attention to the seismic performance of fault-crossing transmission TTLSs,particularly in terms of considering the impact of permanent ground motion displacements(PGMDs).This study attempts to address this concern by evaluating the seismic performance of TTLSs exposed to fault earthquakes.Three strike-slip ground motions are carefully selected,and the corresponding PGMDs are accurately replicated through baseline adjustment.A meticulously designed and fabricated reduced-scale experimental model of a TTLS is then employed to investigate the influence of the fault crossing location(FCL)on its seismic performance.The shake table tests conducted unequivocally demonstrate that PGMDs significantly amplify the seismic responses of the TTLS and identify the most unfavorable FCL.Furthermore,a finite element model(FEM)is developed and its accuracy is validated by comparing it with the experimental results.Parametric analyses are conducted to explore the effects of fault crossing angles(FCAs)and PGMD amplitudes on the seismic performances of TTLSs.This study is expected to contribute valuable insights for the seismic design and performance analysis of TTLSs crossing fault areas.展开更多
Phase classification has a clear guiding significance for the design of high entropy alloys.For mutually exclusive and non-mutually exclusive classifications,the composition descriptors,commonly used physical paramete...Phase classification has a clear guiding significance for the design of high entropy alloys.For mutually exclusive and non-mutually exclusive classifications,the composition descriptors,commonly used physical parameter descriptors,elemental-property descriptors,and descriptors extracted from the periodic table representation(PTR)by the convolutional neural network were collected.Appropriate selection among features with rich information is helpful for phase classification.Based on random forest,the accuracy of the four-label classification and balanced accuracy of the five-label classification were improved to be 0.907 and 0.876,respectively.The roles of the four important features were summarized by interpretability analysis,and a new important feature was found.The model extrapolation ability and the influence of Mo were demonstrated by phase prediction in(CoFeNiMn)_(1-x)Mo_(x).The phase information is helpful for the hardness prediction,the classification results were coupled with the PTR of hardness data,and the prediction error(the root mean square error)was reduced to 56.69.展开更多
Shaking table tests are widely used to evaluate seismic effects on railway structures,but accurately measuring rail displacement remains a significant challenge owing to the nonlinear characteristics of large displace...Shaking table tests are widely used to evaluate seismic effects on railway structures,but accurately measuring rail displacement remains a significant challenge owing to the nonlinear characteristics of large displacements,ambient noise interference,and limitations in displacement meter installation.In this paper,a novel method that integrates the Kanade-Lucas-Tomasi(KLT)feature tracker with an extended Kalman filter(EKF)is presented for measuring rail displacement during shaking table tests.The method employs KLT feature tracker and a random sample consensus algorithm to extract and track key feature points,while EKF optimally estimates dynamic states by accounting for system noise and observation errors.Shaking table test results demonstrate that the proposed method achieves an acceleration root mean square error of 0.300 m/s^(2)and a correlation with accelerometer data exceeding 99.7%,significantly outper-forming the original KLT approach.This innovative method provides a more efficient and reliable solution for measuring rail displacement under large nonlinear vibrations.展开更多
A rising water table increases soil water content,reduces soil strength,and amplifies vibrations under identical train loads,thereby posing greater risks to train operations.To investigate this phenomenon,we used a 2....A rising water table increases soil water content,reduces soil strength,and amplifies vibrations under identical train loads,thereby posing greater risks to train operations.To investigate this phenomenon,we used a 2.5D finite element(FE)model of a coupled vehicle–embankment–ground system based on Biot’s theory.The ground properties were derived from a typical soil profile of the Yangtze River basin,using geological data from Shanghai,China.The findings indicate that a rise in the water table leads to increased dynamic displacements of both the track and the ground.This amplification effect extends beyond the depth of the water table,impacting the entire embankment–foundation cross-section,and intensifies with higher train speeds.However,the water table rise has a limited impact on the critical speed of trains and dominant frequency contents.The dynamic response of the embankment is more significantly affected by water table rises within the subgrade than by those within the ground.When the water table rises into the subgrade,significant excess pore pressure is generated inside the embankment,causing a substantial drop in effective stress.As a result,the stress path of the soil elements in the subgrade approaches the Mohr-Coulomb failure line,increasing the likelihood of soil failure.展开更多
Linear vibration table can provide harmonic accelerations to excite the nonlinear error terms of Pendulous Integrating Gyro Accelerometer(PIGA).Integral precession calibration method is proposed to calibrate PIGA on a...Linear vibration table can provide harmonic accelerations to excite the nonlinear error terms of Pendulous Integrating Gyro Accelerometer(PIGA).Integral precession calibration method is proposed to calibrate PIGA on a linear vibration table in this paper.Based on the precise expressions of PIGA’s inputs,the error calibration model of PIGA is established.Precession angular velocity errors of PIGA are suppressed by integer periodic precession and the errors caused by non-integer periods vibrating are compensated.The complete calibration process,including planning,preparation,PIGA testing,and coefficient identification,is designed to optimize the test operations and evaluate the calibration results.The effect of the main errors on calibration uncertainty is analyzed and the relative sensitivity function is proposed to further optimize the test positions.Experimental and simulation results verify that the proposed 10-position calibration method can improve calibration uncertainties after compensating for the related errors.The order of calibration uncertainties of the second-and third-order coefficients are decreased to 10^(-8)(rad.s^(-1))/g^(2)and 10^(-8)(rad.s^(-1))/g3,respectively.Compared with the other two classical calibration methods,the calibration uncertainties of PIGA’s nonlinear error coefficients can be effectively reduced and the proportional residual errors are decreased less than 3×10-6(rad.s^(-1))/g by using the proposed calibration method.展开更多
As an important part of nonstructural components,the seismic response of indoor water supply pipes deserves much attention.This paper presents shaking table test research on water supply pipes installed in a full-scal...As an important part of nonstructural components,the seismic response of indoor water supply pipes deserves much attention.This paper presents shaking table test research on water supply pipes installed in a full-scale reinforced concrete(RC)frame structure.Different material pipes and different methods for penetrating the reinforced concrete floors are combined to evaluate the difference in seismic performance.Floor response spectra and pipe acceleration amplification factors based on test data are discussed and compared with code provisions.A seismic fragility study of displacement demand is conducted based on numerical simulation.The acceleration response and displacement response of different combinations are compared.The results show that the combination of different pipe materials and different passing-through methods can cause obvious differences in the seismic response of indoor riser pipes.展开更多
The seismic performance of a caisson structure under two types of models with a saturated sandy foundation(CSS)and an expanded polystyrene(EPS)composite soil foundation(CES)are studied using shaking table tests.The ma...The seismic performance of a caisson structure under two types of models with a saturated sandy foundation(CSS)and an expanded polystyrene(EPS)composite soil foundation(CES)are studied using shaking table tests.The macro phenomena of the two different foundation models are described and analyzed.The effects of the replacement of EPS composite soil on seismic-induced liquefaction of backfill and the dynamic performance of a caisson structure are evaluated in detail.The results show that the excess pore water pressure generation in the CES is significantly slower than that in the CSS during the shaking.The dynamic earth pressure acting on the caisson has a triangular shape.The response of horizontal acceleration,displacement,settlement,and rotation angle of the caisson in the CES is smaller than that in the CSS,which means the caisson in the CES has a better seismic performance.Furthermore,the out-of-phase phenomenon between dynamic earth thrust and inertial force in the CES is more obvious than that in the CSS,which is beneficial to reduce the lateral force and improve the stability of the caisson structure.展开更多
When an underground structure passes through a liquefiable soil layer,the soil liquefaction may pose a significant threat to the structure.A centrifuge shaking table test was performed to research the seismic response...When an underground structure passes through a liquefiable soil layer,the soil liquefaction may pose a significant threat to the structure.A centrifuge shaking table test was performed to research the seismic response of underground structures in liquefiable interlayer sites,and a valid numerical model was obtained through simulation model test.Finally,the calibrated numerical model was used to perform further research on the influence of various distribution characteristics of liquefiable interlayers on the seismic reaction of underground structures.The key findings are as follows.The structure faces the most unfavorable condition once a liquefiable layer is located in the middle of the underground structure.When a liquefiable layer exists in the middle of the structure,the seismic reactions of both the underground structure and model site will increase with the rise of the thickness of the liquefiable interlayer.The inter-story drift of the structure in the non-liquefiable site is much smaller than that in the liquefiable interlayer site.The inter-story drift of the structure is not only associated with the site displacement and the soil-structure stiffness ratio but also closely associated with the slippage of the soil-structure contact interface under the condition of large deformation of the site.展开更多
Method: In Cameroon limited data are available regarding the prevalence of enteric bacteria associated with table egg consuming infections. As such, a situational-based study was performed in patients with complains o...Method: In Cameroon limited data are available regarding the prevalence of enteric bacteria associated with table egg consuming infections. As such, a situational-based study was performed in patients with complains of stomach disorders after egg consumption. Data related to sociodemographic characteristics and other factors were collected using a structured based questionnaire. Stool culture of utmost importance in stomach disorders patients and serum were collected for typhoid serological test. Results: A total of 207 participants took part in the survey, Results indicated nontyphoidal Salmonella infections were highest in the 3 areas of study with Mfoundi (73.44%) having the highest level of infection compared to other bacterial infection. other enteric bacteria associated to this infection were E. coli serotype 157, Aeromonas, Citrobacter freundii, Enterobacter cloaca and typhi salmonella. Meanwhile salmonelosis caused by typhic salmonella had highest prevalence in the Lekie Division (13.11%) as a result of poor hygienic practices associated with the conservation and preparation of eggs, Stool culture was observed to detect more positive cases in the diagnosis of typhoid fever than Widal test, but with no statistically significant (p > 0.05) difference between the stool culture and Widal test in the 3 areas of study. Conclusion: this study revealed that egg consumers are pruned to enteric bacterial and salmonella infections depending on how and where egg is consumed.展开更多
Computer-generated holography technology has been widely applied,and as research in this field deepens,the demand for memory and computational power in small AR and VR devices continues to increase.This paper presents...Computer-generated holography technology has been widely applied,and as research in this field deepens,the demand for memory and computational power in small AR and VR devices continues to increase.This paper presents a hologram generation method,i.e.,a symmetrically high-compressed look-up table method,which can reduce memory usage by50%.In offline computing,half of the basic horizontal and vertical modulation factors are stored,halving the memory requirements without affecting inline speed.Currently,its potential extends to various holographic applications,including the production of optical diffraction elements.展开更多
Nitrogen deposition and water tables are important factors to control soil microbial community structure.However,the specific effects and mechanisms of nitrogen deposition and water tables coupling on bacterial divers...Nitrogen deposition and water tables are important factors to control soil microbial community structure.However,the specific effects and mechanisms of nitrogen deposition and water tables coupling on bacterial diversity,abundance,and community structure in arid alpine wetlands remain unclear.The nitrogen deposition(0,10,and 20 kg N/(hm^(2)•a))experiments were conducted in the Bayinbulak alpine wetland with different water tables(perennial flooding,seasonal waterlogging,and perennial drying).The 16S rRNA(ribosomal ribonucleic acid)gene sequencing technology was employed to analyze the changes in bacterial community diversity,network structure,and function in the soil.Results indicated that bacterial diversity was the highest under seasonal waterlogging condition.However,nitrogen deposition only affected the bacterial Chao1 and beta diversity indices under seasonal waterlogging condition.The abundance of bacterial communities under different water tables showed significant differences at the phylum and genus levels.The dominant phylum,Proteobacteria,was sensitive to soil moisture and its abundance decreased with decreasing water tables.Although nitrogen deposition led to changes in bacterial abundance,such changes were small compared with the effects of water tables.Nitrogen deposition with 10 kg N/(hm^(2)•a)decreased bacterial edge number,average path length,and robustness.However,perennial flooding and drying conditions could simply resist environmental changes caused by 20 kg N/(hm^(2)•a)nitrogen deposition and their network structure remain unchanged.The sulfur cycle function was dominant under perennial flooding condition,and carbon and nitrogen cycle functions were dominant under seasonal waterlogging and perennial drying conditions.Nitrogen application increased the potential function of part of nitrogen cycle and decreased the potential function of sulfur cycle in bacterial community.In summary,composition of bacterial community in the arid alpine wetland was determined by water tables,and diversity of bacterial community was inhibited by a lower water table.Effect of nitrogen deposition on bacterial community structure and function depended on water tables.展开更多
Over millennia, nobody has been able to predict where prime numbers sprout or how they spread. This study establishes the Periodic Table of Primes (PTP) using four prime numbers 2, 3, 5, and 7. We identify 48 integers...Over millennia, nobody has been able to predict where prime numbers sprout or how they spread. This study establishes the Periodic Table of Primes (PTP) using four prime numbers 2, 3, 5, and 7. We identify 48 integers out of a period 2×3×5×7=210 to be the roots of all primes as well as composites without factors of 2, 3, 5, and 7. Each prime, twin primes, or composite without factors of 2, 3, 5, and 7 is an offspring of the 48 integers uniquely allocated on the PTP. Three major establishments made in the article are the Formula of Primes, the Periodic Table of Primes, and the Counting Functions of Primes and Twin Primes.展开更多
文摘Bemisia tabaci is a polyphagous herbivore that feeds on a wide range of horticultural and ornamental crops cultivated under diverse ecological zones. In Sierra Leone, B. tabaci is found to infest a wide range of vegetable crops by directly feeding on phloem sap thereby inducing physiological disorders, and also serve as a vector to gemini viruses. Invariably the destructive feeding of B. tabaci affects the productivity and aesthetic values of vegetables and other horticultural crops and hence is considered a serious economic pest. A bioassay experiment was carried out by rearing B. tabaci populations on four vegetable crops under controlled laboratory conditions to determine its life table and demographic parameters. Results showed that the intrinsic rate of growth which measures the population size and growth pattern was highest for populations reared on tomato crops with the following values: rm 0.145 female female−1 day−1, the gross reproduction rate (Ro), and finite growth rate λ were highest for population reared on tomato, correspondingly the development period from egg-adult emergence was shortest with a value of 26 d. Conversely, the computed demographical parameters rm, λ and Ro for the population reared on sweet pepper were 0.106 female female−1 day−1 respectively, with a corresponding development period egg-adult emergence as 36d. The computed biological parameters for okra and garden egg varied with intermediary values between tomato and pepper host materials. The survivorship rates were quite significant for the smaller instars (Instars 1-III) with over 80% surviving to pre-pupa and pupa stage for the populations reared for all the test materials. High mortality was noticed for the pre-pupa and pupa stages as their survival rates were significantly low compared to the high survival rates of the smaller instars. Less than 50% of pupae failed to emerge to adults except for populations reared on tomato test materials where 52% emerged to adults. The study indicated tomato as the most suitable host among the four vegetable crops. Although life table and demographic parameters are invaluable information for forecasting pest populations and help in designing pest management efforts, further investigations such as the economic threshold and economic injury levels of B. tabaci population are requisite decision tools for sound pest management decisions of B. tabaci on these vegetable crops. The information obtained from this investigation would be quite relevant for extension service and pest management practitioners where mixed vegetable farming is a common practice.
文摘On April 19th,"the Youth Table Tennis Programme—Photo Exhibition of Zhou Enlai and the Bandung Conference&China-ASEAN(Indonesia)Youth Table Tennis Training Camp"opened in Jakarta,Indonesia.The event was guided by the Chinese Embassy in Indonesia and co-organised by the ASEAN-China Centre(ACC),the Memorial to Zhou Enlai and Deng Yingchao,the China Friendship Foundation for Peace and Development,the Beijing One Heart Sphere Charity Foundation,and the Enlai Foundation.
文摘Table manners are important in manycultures.Inmost countries,youwait untileveryone has food before eating.Youalso don't put your elbows on the table.It's not polite to eat too fast.And youshouldn't talk with food in yourmouth orchew with your mouth open.
基金funding support from the National Nature Science Foundation of China(Grant No.41931296)the Open Research Project of Sichuan Provincial Key Laboratory for Major Hazard Source Monitoring and Control(Grant No.KFKT2023-4)the 57#Project(Grant No.JH2024015).
文摘Weak interlayers play a crucial role in the seismic performance of bedding slopes;however,the effects of structural surface development within these layers remain underexplored.This study presents two scaled models of bedding slopes,each with different weak interlayers:one with a homogeneous weak layer and another with discontinuous interfaces.Shaking table tests were conducted to compare their seismic performance.The results show that the peak ground acceleration(PGA)values above the weak interlayer in model A were significantly higher than those in model B,with the differences increasing as the input wave amplitude increased.The peak earth pressure(PEP)values at the tensile failure boundary at the rear edge of model A were also higher,whereas those within the weak layer at the toe of model A were lower than those in model B.Deformation analysis revealed that the maximum principal strain in model A initially appeared at the upper part of the tensile failure boundary,while the maximum shear strain was concentrated near the rear edge within the weak layer.In contrast,model B exhibited the opposite strain distribution.These findings provide insight into the impact of weak interlayers on the dynamic response and deformation of bedding slopes,highlighting the importance of considering this factor in seismic landslide investigations and failure mode predictions.
基金funded by the National Natural Science Foundation of China(Grant No.42377195)。
文摘A fault is a geological structure characterized by significant displacement of rock masses along a fault plane within the Earth's crust.The Yunnan Tabaiyi Tunnel intersects multiple fault zones,making tunnel construction in fault-prone areas particularly vulnerable to the effects of fault activity due to the complexities of the surrounding geological environment.To investigate the dynamic response characteristics of tunnel structures under varying surrounding rock conditions,a three-dimensional large-scale shaking table physical model test was conducted.This study also aimed to explore the damage mechanisms associated with the Tabaiyi Tunnel under seismic loading.The results demonstrate that poor quality surrounding rock enhances the seismic response of the tunnel.This effect is primarily attributed to the distribution characteristics of acceleration,dynamic strain,and dynamic soil pressure.A comparison between unidirectional and multi-directional(including vertical)seismic motions reveals that vertical seismic motion has a more significant impact on specific tunnel locations.Specifically,the maximum tensile stress is observed at the arch shoulder,with values ranging from 60 to 100 k Pa.Moreover,NPR(Non-Prestressed Reinforced)anchor cables exhibit a substantial constant resistance effect under low-amplitude seismic waves.However,when the input earthquake amplitude reaches 0.8g,local sliding occurs at the arch shoulder region of the NPR anchor cable.These findings underscore the importance of focusing on seismic mitigation measures in fault zones and reinforcing critical areas,such as the arch shoulders,in practical engineering applications.
基金the support from the Outstanding Youth Foundation of Shandong Province(ZR2021YQ31)the National Natural Science Foundation of China(42277135)+5 种基金National Foreign Experts Individual Program(Category Y)(Grant No.Y20240084)the National Natural Science Foundation of China Joint Fund Key Project(U2006225)Special Fund for Taishan Scholar Projectthe Youth Project of Open Funding from Engineering Research Center of Concrete Technology under Marine Environment,Ministry of Education(Grant No.TMduracon202217)the funding from Key Laboratory of Ministry of Education for Coastal Disaster and Protection,Hohai University(Grant No.202206)Shandong Provincial Overseas High-Level Talent Workstation,China。
文摘Seismic-induced landslides critically threaten infrastructure and human safety,especially in sandy slopes where conventional stabilization methods often fail under dynamic loading.This study evaluates circular open-ended anti-slide pipe piles embedded in a two-layer sandy slope with differing geotechnical properties.Ten physical models,including five freefield and five pile-reinforced slopes,were tested on a shaking table.Key seismic responses—acceleration,soil displacement,and bending moments—were monitored using accelerometers,strain gauges,and Digital Image Correlation(DIC).Complementary numerical simulations using Abaqus with a Mohr–Coulomb model validated experimental results.Soil displacement in free-field models under 0.25g shaking was about 3.5 times greater than in reinforced slopes.Bending moments increased with seismic intensity,peaking at depths around five times the pile diameter.Limitations including simplified two-layer soil representation,idealized seismic inputs,and boundary effects inherent to laboratory models restrict direct field application but enable controlled analysis.By combining physical experiments with numerical modeling,the study provides a robust and validated framework for seismic slope stabilization.This integrated approach enhances understanding of soil–pile interaction under seismic loads and offers targeted insights for developing safer and more reliable geotechnical design strategies in earthquake-prone areas.
基金Key International(Regional)Joint Research Project under Grant No.52020105002National Natural Science Foundation of China under Grant No.51991393。
文摘The relative stiffness between underground structures and surrounding soil may significantly influence the dynamic response of such structures.In this study,two underground pipelines were fabricated using rubber joints with varying stiffness,and the corresponding dynamic response was evaluated.Model soils were prepared based on similarity ratios.Next,reduced-scale shaking table tests were conducted to investigate the impact of circular underground structures with varying stiffness joints on the amplification of ground acceleration,dynamic response,and deformation patterns of the underground pipelines.The comparative analysis showed that structures with lower stiffness exert less constraint on the surrounding soil,resulting in a higher amplification factor of ground acceleration.The seismic response of less stiff structures is generally 1.1 to 1.3 times the response of the stiffer structures.Therefore,the seismic response of the variable stiffness pipeline exhibits pronounced characteristics.Rubber joints effectively reduce the seismic response of underground structures,demonstrating favorable isolation effects.Consequently,relative stiffness plays a crucial role in the seismic design of underground structures,and the use of rubber materials in underground structures is advantageous.
基金Basic Science Research Program of the National Research Foundation of Korea under Grant Nos.NRF-2020R1A6A1A03044977 and NRF2022R1A2C2004351。
文摘In this study, shaking table tests were performed to investigate the dynamic characteristics of a mold transformer. Based on the test results, rotary friction dampers were developed to mitigate the excessive lateral displacement that occurred along the direction of the weak stiffness axis of the mold transformer. In addition, shaking table tests were performed by attaching friction dampers to both sides of the mold transformer. Based on the shaking table test results, the natural frequency, mode vector, and damping ratio of the mold transformer were derived using the transfer function and half-power bandwidth. The test results indicated that the use of friction dampers can decrease the displacement and acceleration response of the mold transformer. Finally, dynamic structural models were established considering the component connectivity and mass distribution of the mold transformer. In addition, a numerical strategy was proposed to calibrate the stiffness coefficients of the mold transformer, thereby facilitating the relationship between generalized mass and stiffness. The results indicated that the analytical model based on the calibration strategy of stiffness coefficients can reasonably simulate the dynamic behavior of the mold transformer using friction dampers with regard to transfer function, displacement, and acceleration response.
基金Shandong Provincial Natural Science Foundation for Distinguished Young Scholars under Grant No.ZR2022JQ27the Taishan Scholars Program
文摘Transmission tower-line systems(TTLSs)play a crucial role in the long-distance transmission of electrical energy,often necessitating their crossing through active fault areas.However,previous studies have given limited attention to the seismic performance of fault-crossing transmission TTLSs,particularly in terms of considering the impact of permanent ground motion displacements(PGMDs).This study attempts to address this concern by evaluating the seismic performance of TTLSs exposed to fault earthquakes.Three strike-slip ground motions are carefully selected,and the corresponding PGMDs are accurately replicated through baseline adjustment.A meticulously designed and fabricated reduced-scale experimental model of a TTLS is then employed to investigate the influence of the fault crossing location(FCL)on its seismic performance.The shake table tests conducted unequivocally demonstrate that PGMDs significantly amplify the seismic responses of the TTLS and identify the most unfavorable FCL.Furthermore,a finite element model(FEM)is developed and its accuracy is validated by comparing it with the experimental results.Parametric analyses are conducted to explore the effects of fault crossing angles(FCAs)and PGMD amplitudes on the seismic performances of TTLSs.This study is expected to contribute valuable insights for the seismic design and performance analysis of TTLSs crossing fault areas.
基金supported by the National Natural Science Foundation of China(Nos.51671075,51971086)the Natural Science Foundation of Heilongjiang Province,China(No.LH2022E081)。
文摘Phase classification has a clear guiding significance for the design of high entropy alloys.For mutually exclusive and non-mutually exclusive classifications,the composition descriptors,commonly used physical parameter descriptors,elemental-property descriptors,and descriptors extracted from the periodic table representation(PTR)by the convolutional neural network were collected.Appropriate selection among features with rich information is helpful for phase classification.Based on random forest,the accuracy of the four-label classification and balanced accuracy of the five-label classification were improved to be 0.907 and 0.876,respectively.The roles of the four important features were summarized by interpretability analysis,and a new important feature was found.The model extrapolation ability and the influence of Mo were demonstrated by phase prediction in(CoFeNiMn)_(1-x)Mo_(x).The phase information is helpful for the hardness prediction,the classification results were coupled with the PTR of hardness data,and the prediction error(the root mean square error)was reduced to 56.69.
基金The National Key Research and Development Program of China(No.2021YFB2600600,2021YFB2600601)the National Natural Science Foundation of China(No.52408456)+2 种基金China Postdoctoral Science Foundation(No.2022M720533)College Students’Innovative Entrepreneurial Training Plan Program(No.202410710009)Key Research and Development Program of Shaanxi,China(No.2024SF-YBXM-659).
文摘Shaking table tests are widely used to evaluate seismic effects on railway structures,but accurately measuring rail displacement remains a significant challenge owing to the nonlinear characteristics of large displacements,ambient noise interference,and limitations in displacement meter installation.In this paper,a novel method that integrates the Kanade-Lucas-Tomasi(KLT)feature tracker with an extended Kalman filter(EKF)is presented for measuring rail displacement during shaking table tests.The method employs KLT feature tracker and a random sample consensus algorithm to extract and track key feature points,while EKF optimally estimates dynamic states by accounting for system noise and observation errors.Shaking table test results demonstrate that the proposed method achieves an acceleration root mean square error of 0.300 m/s^(2)and a correlation with accelerometer data exceeding 99.7%,significantly outper-forming the original KLT approach.This innovative method provides a more efficient and reliable solution for measuring rail displacement under large nonlinear vibrations.
基金supported by the National Key Research and Development Program Young Scientist Project(No.2024YFC2911000)the National Natural Science Foundation of China(No.52108308).
文摘A rising water table increases soil water content,reduces soil strength,and amplifies vibrations under identical train loads,thereby posing greater risks to train operations.To investigate this phenomenon,we used a 2.5D finite element(FE)model of a coupled vehicle–embankment–ground system based on Biot’s theory.The ground properties were derived from a typical soil profile of the Yangtze River basin,using geological data from Shanghai,China.The findings indicate that a rise in the water table leads to increased dynamic displacements of both the track and the ground.This amplification effect extends beyond the depth of the water table,impacting the entire embankment–foundation cross-section,and intensifies with higher train speeds.However,the water table rise has a limited impact on the critical speed of trains and dominant frequency contents.The dynamic response of the embankment is more significantly affected by water table rises within the subgrade than by those within the ground.When the water table rises into the subgrade,significant excess pore pressure is generated inside the embankment,causing a substantial drop in effective stress.As a result,the stress path of the soil elements in the subgrade approaches the Mohr-Coulomb failure line,increasing the likelihood of soil failure.
文摘Linear vibration table can provide harmonic accelerations to excite the nonlinear error terms of Pendulous Integrating Gyro Accelerometer(PIGA).Integral precession calibration method is proposed to calibrate PIGA on a linear vibration table in this paper.Based on the precise expressions of PIGA’s inputs,the error calibration model of PIGA is established.Precession angular velocity errors of PIGA are suppressed by integer periodic precession and the errors caused by non-integer periods vibrating are compensated.The complete calibration process,including planning,preparation,PIGA testing,and coefficient identification,is designed to optimize the test operations and evaluate the calibration results.The effect of the main errors on calibration uncertainty is analyzed and the relative sensitivity function is proposed to further optimize the test positions.Experimental and simulation results verify that the proposed 10-position calibration method can improve calibration uncertainties after compensating for the related errors.The order of calibration uncertainties of the second-and third-order coefficients are decreased to 10^(-8)(rad.s^(-1))/g^(2)and 10^(-8)(rad.s^(-1))/g3,respectively.Compared with the other two classical calibration methods,the calibration uncertainties of PIGA’s nonlinear error coefficients can be effectively reduced and the proportional residual errors are decreased less than 3×10-6(rad.s^(-1))/g by using the proposed calibration method.
基金Scientific Research Fund of Institute of Engineering Mechanics,China Earthquake Administration under Grant Nos.2021EEEVL0204 and 2018A02。
文摘As an important part of nonstructural components,the seismic response of indoor water supply pipes deserves much attention.This paper presents shaking table test research on water supply pipes installed in a full-scale reinforced concrete(RC)frame structure.Different material pipes and different methods for penetrating the reinforced concrete floors are combined to evaluate the difference in seismic performance.Floor response spectra and pipe acceleration amplification factors based on test data are discussed and compared with code provisions.A seismic fragility study of displacement demand is conducted based on numerical simulation.The acceleration response and displacement response of different combinations are compared.The results show that the combination of different pipe materials and different passing-through methods can cause obvious differences in the seismic response of indoor riser pipes.
基金National Natural Science Foundation of China under Grant Nos. 52178336 and 52108324Natural Science Research Project of Colleges and Universities in Jiangsu Province of China under Grant No. 18KJA560002+1 种基金the Middle-Aged&Young Science Leaders of Qinglan Project of Universities in Jiangsu Province of ChinaPostgraduate Research&Practice Innovation Program in Jiangsu Province of China under Grant No. KYCX24_1585
文摘The seismic performance of a caisson structure under two types of models with a saturated sandy foundation(CSS)and an expanded polystyrene(EPS)composite soil foundation(CES)are studied using shaking table tests.The macro phenomena of the two different foundation models are described and analyzed.The effects of the replacement of EPS composite soil on seismic-induced liquefaction of backfill and the dynamic performance of a caisson structure are evaluated in detail.The results show that the excess pore water pressure generation in the CES is significantly slower than that in the CSS during the shaking.The dynamic earth pressure acting on the caisson has a triangular shape.The response of horizontal acceleration,displacement,settlement,and rotation angle of the caisson in the CES is smaller than that in the CSS,which means the caisson in the CES has a better seismic performance.Furthermore,the out-of-phase phenomenon between dynamic earth thrust and inertial force in the CES is more obvious than that in the CSS,which is beneficial to reduce the lateral force and improve the stability of the caisson structure.
基金National Natural Science Foundation of China under Grant No.52078020。
文摘When an underground structure passes through a liquefiable soil layer,the soil liquefaction may pose a significant threat to the structure.A centrifuge shaking table test was performed to research the seismic response of underground structures in liquefiable interlayer sites,and a valid numerical model was obtained through simulation model test.Finally,the calibrated numerical model was used to perform further research on the influence of various distribution characteristics of liquefiable interlayers on the seismic reaction of underground structures.The key findings are as follows.The structure faces the most unfavorable condition once a liquefiable layer is located in the middle of the underground structure.When a liquefiable layer exists in the middle of the structure,the seismic reactions of both the underground structure and model site will increase with the rise of the thickness of the liquefiable interlayer.The inter-story drift of the structure in the non-liquefiable site is much smaller than that in the liquefiable interlayer site.The inter-story drift of the structure is not only associated with the site displacement and the soil-structure stiffness ratio but also closely associated with the slippage of the soil-structure contact interface under the condition of large deformation of the site.
文摘Method: In Cameroon limited data are available regarding the prevalence of enteric bacteria associated with table egg consuming infections. As such, a situational-based study was performed in patients with complains of stomach disorders after egg consumption. Data related to sociodemographic characteristics and other factors were collected using a structured based questionnaire. Stool culture of utmost importance in stomach disorders patients and serum were collected for typhoid serological test. Results: A total of 207 participants took part in the survey, Results indicated nontyphoidal Salmonella infections were highest in the 3 areas of study with Mfoundi (73.44%) having the highest level of infection compared to other bacterial infection. other enteric bacteria associated to this infection were E. coli serotype 157, Aeromonas, Citrobacter freundii, Enterobacter cloaca and typhi salmonella. Meanwhile salmonelosis caused by typhic salmonella had highest prevalence in the Lekie Division (13.11%) as a result of poor hygienic practices associated with the conservation and preparation of eggs, Stool culture was observed to detect more positive cases in the diagnosis of typhoid fever than Widal test, but with no statistically significant (p > 0.05) difference between the stool culture and Widal test in the 3 areas of study. Conclusion: this study revealed that egg consumers are pruned to enteric bacterial and salmonella infections depending on how and where egg is consumed.
基金Project supported by the National Natural Science Foundation of China (Grant No.62205350)the Special Project of Central Government Guiding Local Science and Technology Development in Beijing 2020 (Grant No.Z20111000430000)the Guangxi Nanning Key R&D Program (Grant No.20233067)。
文摘Computer-generated holography technology has been widely applied,and as research in this field deepens,the demand for memory and computational power in small AR and VR devices continues to increase.This paper presents a hologram generation method,i.e.,a symmetrically high-compressed look-up table method,which can reduce memory usage by50%.In offline computing,half of the basic horizontal and vertical modulation factors are stored,halving the memory requirements without affecting inline speed.Currently,its potential extends to various holographic applications,including the production of optical diffraction elements.
基金supported by the National Natural Science Foundation of China(31960258)the Graduate Research Innovation Project of Xinjiang Uygur Autonomous Region(XJ2023G119).
文摘Nitrogen deposition and water tables are important factors to control soil microbial community structure.However,the specific effects and mechanisms of nitrogen deposition and water tables coupling on bacterial diversity,abundance,and community structure in arid alpine wetlands remain unclear.The nitrogen deposition(0,10,and 20 kg N/(hm^(2)•a))experiments were conducted in the Bayinbulak alpine wetland with different water tables(perennial flooding,seasonal waterlogging,and perennial drying).The 16S rRNA(ribosomal ribonucleic acid)gene sequencing technology was employed to analyze the changes in bacterial community diversity,network structure,and function in the soil.Results indicated that bacterial diversity was the highest under seasonal waterlogging condition.However,nitrogen deposition only affected the bacterial Chao1 and beta diversity indices under seasonal waterlogging condition.The abundance of bacterial communities under different water tables showed significant differences at the phylum and genus levels.The dominant phylum,Proteobacteria,was sensitive to soil moisture and its abundance decreased with decreasing water tables.Although nitrogen deposition led to changes in bacterial abundance,such changes were small compared with the effects of water tables.Nitrogen deposition with 10 kg N/(hm^(2)•a)decreased bacterial edge number,average path length,and robustness.However,perennial flooding and drying conditions could simply resist environmental changes caused by 20 kg N/(hm^(2)•a)nitrogen deposition and their network structure remain unchanged.The sulfur cycle function was dominant under perennial flooding condition,and carbon and nitrogen cycle functions were dominant under seasonal waterlogging and perennial drying conditions.Nitrogen application increased the potential function of part of nitrogen cycle and decreased the potential function of sulfur cycle in bacterial community.In summary,composition of bacterial community in the arid alpine wetland was determined by water tables,and diversity of bacterial community was inhibited by a lower water table.Effect of nitrogen deposition on bacterial community structure and function depended on water tables.
文摘Over millennia, nobody has been able to predict where prime numbers sprout or how they spread. This study establishes the Periodic Table of Primes (PTP) using four prime numbers 2, 3, 5, and 7. We identify 48 integers out of a period 2×3×5×7=210 to be the roots of all primes as well as composites without factors of 2, 3, 5, and 7. Each prime, twin primes, or composite without factors of 2, 3, 5, and 7 is an offspring of the 48 integers uniquely allocated on the PTP. Three major establishments made in the article are the Formula of Primes, the Periodic Table of Primes, and the Counting Functions of Primes and Twin Primes.
