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Seismology and Climatology: A Study of Seismological Impacts of Climate Change in Indonesia
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作者 Lukundo Mtambo Xingxiang Tao 《Atmospheric and Climate Sciences》 2024年第2期210-220,共11页
Climate change has been a matter of discourse for the last several decades. Much research has been conducted regarding the causes and impacts of climate change around the world. The current research contributes to the... Climate change has been a matter of discourse for the last several decades. Much research has been conducted regarding the causes and impacts of climate change around the world. The current research contributes to the knowledge of the influence of climate change on our environment, with emphasis on earthquake occurrences in the region of Indonesia. Using global temperature anomaly as a measure of climate change, and earthquake data in Indonesia for the period 1900-2022, the paper seeks to find a relationship (if any) between the two variables. Statistical methods used include normal distribution analysis, linear regression and correlation test. The results show peculiar patterns in the progression of earthquake occurrences as well as global temperature anomaly occurring in the same time periods. The findings also indicated that the magnitudes of earthquakes remained unaffected by global temperature anomalies over the years. Nonetheless, there appears to be a potential correlation between temperature anomalies and the frequency of earthquake occurrences. As per the results, an increase in temperature anomaly is associated with a higher frequency of earthquakes. 展开更多
关键词 EARTHQUAKES CLIMATOLOGY Climate Change SEISMOLOGY Correlation Linear Regression Indonesia
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Monitoring Study of Long-Term Land Subsidence during Subway Operation in High-Density Urban Areas Based on DInSAR-GPS-GIS Technology and Numerical Simulation
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作者 Yu Song Xuejun Chen +4 位作者 Baoping Zou Jundong Mu Rusheng Hu Siqi Cheng Shengli Zhao 《Computer Modeling in Engineering & Sciences》 SCIE EI 2023年第2期1021-1039,共19页
During subway operation,various factors will cause long-term land subsidence,such as the vibration subsidence of foundation soil caused by train vibration load,incomplete consolidation deformation of foundation soil d... During subway operation,various factors will cause long-term land subsidence,such as the vibration subsidence of foundation soil caused by train vibration load,incomplete consolidation deformation of foundation soil during tunnel construction,dense buildings and structures in the vicinity of the tunnel,and changes in water level in the stratum where the tunnel is located.The monitoring of long-term land subsidence during subway operation in high-density urban areas differs from that in low-density urban construction areas.The former is the gathering point of the entire urban population.There are many complex buildings around the project,busy road traffic,high pedestrian flow,and less vegetation cover.Several existing items requiremonitoring.However,monitoring distance is long,and providing early warning is difficult.This study uses the 2.8 km operation line between Wulin Square station and Ding’an Road station of Hangzhou Subway Line 1 as an example to propose the integrated method of DInSAR-GPS-GIS technology and the key algorithm for long-term land subsidence deformation.Then,it selects multiscene image data to analyze long-termland subsidence of high-density urban areas during subway operation.Results show that long-term land subsidence caused by the operation of Wulin Square station to Ding’an Road station of Hangzhou Subway Line 1 is small,with maximumsubsidence of 30.64 mm,and minimumsubsidence of 11.45 mm,and average subsidence ranging from 19.27 to 21.33 mm.And FLAC3D software was used to verify the monitoring situation,using the geological conditions of the soil in the study area and the tunnel profile to simulate the settlement under vehicle load,and the simulation results tended to be consistent with the monitoring situation. 展开更多
关键词 Long-term land subsidence subway operation DInSAR-GPS-GIS technology high-density urban areas urban subway numerical simulation
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Dynamic Mechanical Behavior and Numerical Simulation of an Ancient Underground Rock Mass under Impact Loading
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作者 Baoping Zou Zhiping Liu +2 位作者 Weifeng Jin Haonan Ding Zhanyou Luo 《Computer Modeling in Engineering & Sciences》 SCIE EI 2023年第1期517-539,共23页
To study the dynamic mechanical properties of tuff under different environmental conditions,the tuff from an ancient quarry in Shepan Island was prepared.The impact damage to the rock was tested using a triaxial dynam... To study the dynamic mechanical properties of tuff under different environmental conditions,the tuff from an ancient quarry in Shepan Island was prepared.The impact damage to the rock was tested using a triaxial dynamic impact mechanical testing system(TDIMTS)with different ground stresses,temperatures,and groundwater pressures.The time-strain relationship,dynamic stress-strain relationship,energy dissipation law,energy-peak strain relationship,and the impact damage pattern of the tuff specimens under impact air pressures were investigated.The TDIMTS experiment on ancient underground rock mass under impact loading was also simulated using the finite element analysis software LS-DYNA based on the Holmquist-Johnson-Cook(HJC)material model.The dynamic failure process,failure pattern and peak stress of tuff specimen were calculated.The simulation results obtained using the above methods were in good agreement with the experimental results.The results of the dynamic experiment show that with the same local stress,groundwater pressure,and temperature,the damage to the tuff specimens caused by blasting and quarrying disturbances gradually increases as the impact pressure increases.Under the same local stress,groundwater pressure,and temperature,the energy required to rupture the tuffs in ancient underground caverns is relatively small if the impact pressure is low accordingly,but as the impact pressure increases,the damage to the tuff caused by quarrying disturbance gradually increases.The damage gradually increases and the degree of damage to the tuff and the strain energy exhibit asymptotic growth when the tuff specimens are subjected to the greater strain energy,increasing the degree of rupturing of the tuff.In addition,the average crushing size decreases with increasing strain energy.By comparing the simulation results with the experimental results,it was found that the HJC model reflected the dynamic impact performance of tuff specimen,and the simulation results showed an evident strain rate effect.These results of this study can offer some guidance and theoretical support for the stability evaluation,protection,and safe operation of the ancient underground caverns in future. 展开更多
关键词 Ancient underground caverns numerical simulation thermal-hydraulic-mechanical coupling dynamic impact TUFF stability of surrounding rock
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THE FEKETE-SZEG?INEQUALITY AND SUCCESSIVE COEFFICIENTS DIFFERENCE FOR A SUBCLASS OF CLOSE-TO-STARLIKE MAPPINGS IN COMPLEX BANACH SPACES
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作者 徐庆华 方炜康 +1 位作者 冯伟珩 刘太顺 《Acta Mathematica Scientia》 SCIE CSCD 2023年第5期2075-2088,共14页
Let C be the familiar class of normalized close-to-convex functions in the unit disk.In[17],Koepf demonstrated that,as to a function■in the class C,■By applying this inequality,it can be proven that‖a3|-|a2‖≤1 fo... Let C be the familiar class of normalized close-to-convex functions in the unit disk.In[17],Koepf demonstrated that,as to a function■in the class C,■By applying this inequality,it can be proven that‖a3|-|a2‖≤1 for close-to-convex functions.Now we generalized the above conclusions to a subclass of close-to-starlike mappings defined on the unit ball of a complex Banach space. 展开更多
关键词 Fekete and Szego inequality successive coefficients difference bound close-to-starlike mappings complex Banach space
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BOUNDEDNESS AND COMPACTNESS FOR THE COMMUTATOR OF THEω-TYPE CALDER′ON-ZYGMUND OPERATOR ON LORENTZ SPACE
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作者 陶祥兴 曾媛 喻晓 《Acta Mathematica Scientia》 SCIE CSCD 2023年第4期1587-1602,共16页
In this paper,the authors consider theω-type Calder´on-Zygmund operator T_(ω)and the commutator[b,T_(ω)]generated by a symbol function b on the Lorentz space L^(p,r)(X)over the homogeneous space(X,d,μ).The bo... In this paper,the authors consider theω-type Calder´on-Zygmund operator T_(ω)and the commutator[b,T_(ω)]generated by a symbol function b on the Lorentz space L^(p,r)(X)over the homogeneous space(X,d,μ).The boundedness and the compactness of the commutator[b,T_(ω)]on Lorentz space L^(p,r)(X)are founded for any p∈(1,∞)and r∈[1,∞). 展开更多
关键词 ω-type Calder´on-Zygmund operator COMMUTATORS Lorentz space homogeneous space
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Role of Lanthanide in the Electronic Properties of RbLn_(2)Fe_(4)As_(4)O_(2)(Ln=Sm and Ho)Superconductors
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作者 黄衣娜 叶兆丰 +1 位作者 刘大勇 邱航强 《Chinese Physics Letters》 SCIE EI CAS CSCD 2023年第9期101-106,共6页
We focus on the effect of ionic radius of lanthanides and the number of electrons in 4f orbitals on the superconducting temperature in 12442-type iron-based superconductors RbLn_(2)Fe_(4)As_(4)O_(2)(Ln=Sm and Ho).Elec... We focus on the effect of ionic radius of lanthanides and the number of electrons in 4f orbitals on the superconducting temperature in 12442-type iron-based superconductors RbLn_(2)Fe_(4)As_(4)O_(2)(Ln=Sm and Ho).Electronic properties of RbSm_(2)Fe_(4)As_(4)O_(2) and RbHo2Fe4As4O2with the largest differences of ionic radii and numbers of electrons in 4f orbital,and the largest difference of superconducting temperatures by using firstprinciples calculations.We predict that the ground state of RbLn_(2)Fe_(4)As_(4)O_(2) is spin-density-wave-type in-plane striped antiferromagnet,and the magnetic moment around each Fe atom is about 2μB.RbSm_(2)Fe_(4)As_(4)O_(2)has a great influence on the energy band near theΓpoint,and a Dirac-like dispersion energy band appears.This band is mainly contributed by the dz2orbital of Fe,which proves that RbSm_(2)Fe_(4)As_(4)O_(2)has a stronger threedimensionality.At the same time,this extra Fermi surface appears at theΓpoint,which also shows that Sm can effectively enhance the coupling strength within Fe2As2bilayers.This is also confirmed by the charge density differenceρ(RbHo_(2)Fe_(4)As_(4)O_(2))-ρ(RbSm_(2)Fe_(4)As_(4)O_(2)).It increases the internal coupling strength of the bilayer Fe_(2)As2layers,which in turn leads to a higher Tcof RbSm_(2)Fe_(4)As_(4)O_(2)than RbHo_(2)Fe_(4)As_(4)O_(2).Determining the details of their electronic structure,which may be closely related to superconductivity,is crucial to understanding the underlying mechanism.Such microscopic studies provide useful clues for our further research of other hightemperature superconductors. 展开更多
关键词 mechanism. ORBITAL LANTHANIDE
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Pocket Modification of x-Amine Transaminase AtATA for Overcoming the Trade-Off Between Activity and Stability Toward 1-Acetonaphthone
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作者 Jiaren Cao Fangfang Fan +6 位作者 Changjiang Lyu Sheng Hu Weirui Zhao Jiaqi Mei Shuai Qiu Lehe Mei Jun Huang 《Engineering》 SCIE EI CAS CSCD 2023年第11期203-214,共12页
Amine transaminases(ATAs)catalyze the asymmetric amination of prochiral ketones or aldehydes to their corresponding chiral amines.However,the trade-off between activity and stability in enzyme engineering represents a... Amine transaminases(ATAs)catalyze the asymmetric amination of prochiral ketones or aldehydes to their corresponding chiral amines.However,the trade-off between activity and stability in enzyme engineering represents a major obstacle to the practical application of ATAs.Overcoming this trade-off is important for developing robustly engineered enzymes and a universal approach for ATAs.Herein,we modified the binding pocket of co-ATA from Aspergillus terreus(AtATA)to identify the key amino acid residues controlling the activity and stability of AtATA toward 1-acetonaphthone.We discovered a structural switch comprising four key amino acid sites(R128,V149,L182,and L187),as well as the"best"mutant(AtATAD224K/V149A/L182 F/L187F;termed M4).Compared to the parent enzyme AtATAD224K(AtATAPa),M4 increased the catalytic efficiency(k_(cat)/K_(m)^(1-acetonaphthone),where kcatis the constant of catalytic activities and is 10.1 min^(-1),K_(m)^(1-acetonaphthoneis) Michaelis-Menten constant and is 1.7 mmol·L^(-1))and half-life(t1/2)by 59-fold to 5.9 L·min^(-1)·mmol-1and by 1.6-fold to 46.9 min,respectively.Moreover,using M4 as the biocatalyst,we converted a 20 mmol·L^(-1)aliquot of 1-acetonaphthone in a 50 mL scaled-up system to the desired product,(R)-(+)-1(1-naphthyl)ethylamine((R)-NEA),with 78%yield and high enantiomeric purity(R>99.5%)within 10 h.M4 also displayed significantly enhanced activity toward various 1-acetonaphthone analogs.The related structural properties derived by analyzing structure and sequence information of robust ATAs illustrated their enhanced activity and thermostability.Strengthening of intramolecular interactions and expansion of the angle between the substratebinding pocket and the pyridoxal 5’-phosphate(PLP)-binding pocket contributed to synchronous enhancement of ATA thermostability and activity.Moreover,this pocket engineering strategy successfully transferred enhanced activity and thermostability to three other ATAs,which exhibited 8%-22%sequence similarity with AtATA.This research has important implications for overcoming the trade-off between ATA activity and thermostability. 展开更多
关键词 Trade-off CO-EVOLUTION Amine transaminase (R)-(+)-1(1-naphthyl)ethylamine
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Study on Multi-Scale Tensile Strength and Tensile Strain of Calcium Silicate Hydrate Layered Nanocomposites Under External Physical Field
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作者 Lei FAN Lele ZHANG 《Research and Application of Materials Science》 2023年第1期1-4,共4页
Calcium silicate hydrate(C-S-H)is the mainly strength source of cement-based materials,but there is little basic research.In this paper,molecular dynamics method is applied to analyze the multi-scale tensile strength ... Calcium silicate hydrate(C-S-H)is the mainly strength source of cement-based materials,but there is little basic research.In this paper,molecular dynamics method is applied to analyze the multi-scale tensile strength and tensile strain of C-S-H layered materials under the condition of external physical fields(temperature and strain rate).The results show that the tensile strength and strain of C-S-H model decrease with temperature raises.The temperature(from 1 K to 600 K)has obvious influence on the tensile strain and strength of C-S-H layered materials.In addition,at(0.00025 ps^(-1)-0.001 ps^(-1)),the tensile strain and strength of C-S-H layered materials are less sensitive to strain rate.The whole model is closer to a 3-dimensional deformation.However,at(0.001 ps^(-1)-0.005 ps^(-1)),the dynamic load effect begins to increase,and the work done by the load per unit time increased.The tensile strain and strength of C-S-H layered materials indicates intensified by the change of strain rate.The energies are randomly distributed in the system,not concentrated in a certain area. 展开更多
关键词 Hydrated calcium silicate External physical field Multiscale Mechanical properties Molecular dynamics
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The tangential k-Cauchy-Fueter type operator and Penrose type integral formula on the generalized complex Heisenberg group
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作者 REN Guang-zhen SHI Yun KANG Qian-qian 《Applied Mathematics(A Journal of Chinese Universities)》 SCIE CSCD 2024年第1期181-190,共10页
The tangential k-Cauchy-Fueter operator and k-CF functions are counterparts of the tangential Cauchy–Riemann operator and CR functions on the Heisenberg group in the theory of several complex variables,respectively.I... The tangential k-Cauchy-Fueter operator and k-CF functions are counterparts of the tangential Cauchy–Riemann operator and CR functions on the Heisenberg group in the theory of several complex variables,respectively.In this paper,we introduce a Lie group that the Heisenberg group can be imbedded into and call it generalized complex Heisenberg.We investigate quaternionic analysis on the generalized complex Heisenberg.We also give the Penrose integral formula for k-CF functions and construct the tangential k-Cauchy-Fueter complex. 展开更多
关键词 the generalized complex Heisenberg group the tangential k-Cauchy-Fueter type operator Penrose-type integral formula
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A VGGNet-based correction for satellite altimetry-derived gravity anomalies to improve the accuracy of bathymetry to depths of 6500 m
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作者 Xiaolun Chen Xiaowen Luo +6 位作者 Ziyin Wu Xiaoming Qin Jihong Shang Huajun Xu Bin Li Mingwei Wang Hongyang Wan 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2024年第1期112-122,共11页
Understanding the topographic patterns of the seafloor is a very important part of understanding our planet.Although the science involved in bathymetric surveying has advanced much over the decades,less than 20%of the... Understanding the topographic patterns of the seafloor is a very important part of understanding our planet.Although the science involved in bathymetric surveying has advanced much over the decades,less than 20%of the seafloor has been precisely modeled to date,and there is an urgent need to improve the accuracy and reduce the uncertainty of underwater survey data.In this study,we introduce a pretrained visual geometry group network(VGGNet)method based on deep learning.To apply this method,we input gravity anomaly data derived from ship measurements and satellite altimetry into the model and correct the latter,which has a larger spatial coverage,based on the former,which is considered the true value and is more accurate.After obtaining the corrected high-precision gravity model,it is inverted to the corresponding bathymetric model by applying the gravity-depth correlation.We choose four data pairs collected from different environments,i.e.,the Southern Ocean,Pacific Ocean,Atlantic Ocean and Caribbean Sea,to evaluate the topographic correction results of the model.The experiments show that the coefficient of determination(R~2)reaches 0.834 among the results of the four experimental groups,signifying a high correlation.The standard deviation and normalized root mean square error are also evaluated,and the accuracy of their performance improved by up to 24.2%compared with similar research done in recent years.The evaluation of the R^(2) values at different water depths shows that our model can achieve performance results above 0.90 at certain water depths and can also significantly improve results from mid-water depths when compared to previous research.Finally,the bathymetry corrected by our model is able to show an accuracy improvement level of more than 21%within 1%of the total water depths,which is sufficient to prove that the VGGNet-based method has the ability to perform a gravity-bathymetry correction and achieve outstanding results. 展开更多
关键词 gravity anomaly bathymetry inversion VGGNet multibeam sonar satellite altimetry
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Evolution of the “Zhejiang Spirit” During the Forty Years of Reform and Opening-up
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作者 Liao Fangling Wan Bin Lu Dunji 《Contemporary Social Sciences》 2019年第2期121-131,共11页
The "Zhejiang spirit" refers to a theoretical summary of the group consciousness, mental state, value orientation and ideological realm, which is, as a motivating power, owned and recognized by all Zhejiang ... The "Zhejiang spirit" refers to a theoretical summary of the group consciousness, mental state, value orientation and ideological realm, which is, as a motivating power, owned and recognized by all Zhejiang people, and carries Zhejiang peculiarities. President Xi Jinping, during his term of office in Zhejiang, launched a number of seminars and activities to seek "a Zhejiang spirit that moves with the times." Forty years of reform and opening-up, the "Zhejiang spirit" has experienced an evolution that can be summarized as three improvements: from spontaneous formation to deliberate cultivation, from something limited to eastern Zhejiang to an integrating force that spans the entire Zhejiang Province, and from a mere existence to a role that functions adequately. The "Zhejiang spirit" is extracted from the humanistic spirits shaped in all corners of Zhejiang province. It is "an instrumental ensemble played across the entire province," and represents a certain judgment and interpretation. The "Zhejiang spirit" not only describes and summarizes the past and present, but will also guide and motivate the future, and support people in their enterprising and industrious practices to move with the times. 展开更多
关键词 MOVE with the TIMES the "Zhejiang SPIRIT " forty YEARS of REFORM and opening-up
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THIRD-ORDER LOCAL CONTACT AND APPLICATION IN 5-AXIS MACHINING OF SCULPTURED SURFACES 被引量:8
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作者 LIU Guran 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2006年第2期265-267,共3页
为了在用机器制造 sculptured 增加效率,出现,微分几何学的接触原则被用于用机器制造的 5 轴 NC;Thebest 联系在工具之间的状况,表面被研究。通过分析,切割器和表面的交叉线的接触度被知道。与以前的研究相比,理论是限制的更多,... 为了在用机器制造 sculptured 增加效率,出现,微分几何学的接触原则被用于用机器制造的 5 轴 NC;Thebest 联系在工具之间的状况,表面被研究。通过分析,切割器和表面的交叉线的接触度被知道。与以前的研究相比,理论是限制的更多,适合分析几何学的主要表面和计算的产生 thecomputer 的表面并且由超出秒顺序参数进精确第三顺序的几何学。它有计算的明确的过程,并且方程是容易的解决。认为的过程是很清楚的:首先,假定有表面其系数是任意的第三顺序;然后发现圆的最好的姿势以便圆和表面将最仔细在起源位置与对方一起联系:最后,在用机器制造的每个点开发表面进第三顺序的表面并且采用上面提及在用机器制造的每个点发现最好的切割器姿势的结果。作为结果,方程是容易的解决,并且这个概念是清楚的。 展开更多
关键词 数字加工 雕刻面 局部接触 五轴加工
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A Two-stage pH and Temperature Control with Substrate Feeding Strategy for Production of Gamma-aminobutyric Acid by Lactobacillus brevis CGMCC 1306 被引量:7
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作者 彭春龙 黄俊 +3 位作者 胡升 赵伟睿 姚善泾 梅乐和 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2013年第10期1190-1194,共5页
由乳杆菌 brevis CGMCC 1306 优化 gamma-aminobutyric 酸(伽马氨基丁酸) 的生产的方法被调查。结果显示房间生长在 pH 是最大的 5.0,当时 4.5 是的 pH 对伽马氨基丁酸更好形成。为细胞生长的最佳的温度(35 ????
关键词 Γ-氨基丁酸 温度控制 优化生产 短乳杆菌 pH值 GABA 底料 细胞生长
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Spatial-temporal Evolution and Determinants of the Belt and Road Initiative: A Maximum Entropy Gravity Model Approach 被引量:7
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作者 HUANG Qinshi ZHU Xigang +3 位作者 LIU Chunhui WU Wei LIU Fengbao ZHANG Xinyi 《Chinese Geographical Science》 SCIE CSCD 2020年第5期839-854,共16页
The spatial interaction model is an effective way to explore the geographical disparities inherent in the Belt and Road Initiative(BRI) by simulating spatial flows. The traditional gravity model implies the hypothesis... The spatial interaction model is an effective way to explore the geographical disparities inherent in the Belt and Road Initiative(BRI) by simulating spatial flows. The traditional gravity model implies the hypothesis of equilibrium points without any reference to when or how to achieve it. In this paper, a dynamic gravity model was established based on the Maximum Entropy(MaxEnt) theory to estimate and monitor the interconnection intensity and dynamic characters of bilateral relations. In order to detect the determinants of interconnection intensity, a Geodetector method was applied to identify and evaluate the determinants of spatial networks in five dimensions. The empirical study clearly demonstrates a heterogeneous and non-circular spatial structure. The main driving forces of spatial-temporal evolution are foreign direct investment, tourism and railway infrastructure construction, while determinants in different sub-regions show obvious spatial differentiation. Southeast Asian countries are typically multi-island area where aviation infrastructure plays a more important role. North and Central Asian countries regard oil as a pillar industry where power and port facilities have a greater impact on the interconnection. While Western Asian countries are mostly influenced by the railway infrastructure, Eastern European countries already have relatively robust infrastructure where tariff policies provide a greater impetus. 展开更多
关键词 spatial interaction model the Belt and Road Initiative(BRI) Maximum Entropy(MaxEnt)gravity model spatial pattern China
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Expansion of spherical cavity of strain-softening materials with different elastic moduli of tension and compression 被引量:2
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作者 LUO Zhan-you ZHU Xiang-rong GONG Xiao-nan 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2007年第9期1380-1387,共8页
An expansion theory of spherical cavities in strain-softening materials with different moduli of tension and com-pression was presented. For geomaterials,two controlling parameters were introduced to take into account... An expansion theory of spherical cavities in strain-softening materials with different moduli of tension and com-pression was presented. For geomaterials,two controlling parameters were introduced to take into account the different moduli and strain-softening properties. By means of elastic theory with different moduli and stress-softening models,general solutions cal-culating Tresca and Mohr-Coulomb materials' stress and displacement fields of expansion of spherical cavity were derived. The effects caused by different elastic moduli in tensile and compression and strain-softening rates on stress and displacement fields and development of plastic zone of expansion of cavity were analyzed. The results show that the ultimate expansion pressure,stress and displacement fields and development of plastic zone vary with the different elastic moduli and strain-softening prop-erties. If classical elastic theory is adopted and strain-softening properties are neglected,rather large errors may be the result. 展开更多
关键词 球形穴 Mohr-Coulomb材料 弹性理论 应力软化模型
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Simultaneous Spectrophotometric Determination of Three Components Including Deoxyschizandrin by Partial Least Squares Regression 被引量:1
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作者 张立庆 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2005年第3期119-121,共3页
关键词 分光谱测量法 衰退分析 计算机辅助分析 吸收光谱
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Fabrication of immobilized nickel nanoclusters decorated by CxNy species for cellulose conversion to C2,3 oxygenated compounds:Rational design via typical C-and N-sources 被引量:1
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作者 Zhuqian Xiao Xiaolei Wang +5 位作者 Qinqin Yang Chuang Xing Qing Ge Xikun Gai Jianwei Mao Jianbing Ji 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2020年第11期25-36,共12页
Production of chemicals and fuels from microcrystalline cellulose has inspired scholars’ attention. Deactivation of metallic catalysts including acid leaching and hydrothermal aggregation is still one of the core iss... Production of chemicals and fuels from microcrystalline cellulose has inspired scholars’ attention. Deactivation of metallic catalysts including acid leaching and hydrothermal aggregation is still one of the core issues in these systems. To address these problems, we designed and fabricated a series of Ni-W/SiO2 catalysts, which were decorated by CxNy species using C-and N- sources and applied in cellulose conversion to C2,3 oxygenated compounds. The Ni-W/SiO2@CxNy catalysts, underwent complexing and selfassembling process, exhibited special heterojunctions, accompanying strong interactions mainly among Ni phase and CxNy layers. Catalytic results showed that the heterojunctions and outer CxNy layers extensively enhanced productions of hydroxyacetone(HDA) and ethylene glycol(EG) and promoted the hydrothermal stability through prospering in concentration of Lewis pairs from Ni–N—N structure and immobilizing the metallic nanoclusters. 48.25% of EG was yielded under 5.0 MPa H2 pressurized 240 ℃ water for 2.0 h. The Lewis pair further improved the formation of HDA with 20.92% yield. High hydrothermal stability of NiW/SiO2@CxNy catalyst was proved according to the recycling results and trace leaching concentration of Ni and W. This construction of metallic catalysts exploited a new strategy to manufacture extraordinary durability of metallic nanoclusters for cellulose conversion under harsh reaction conditions. 展开更多
关键词 Cellulose HETEROJUNCTION Metallic immobilization Leaching-resistance HYDROXYACETONE
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FEKETE AND SZEG INEQUALITY FOR A SUBCLASS OF STARLIKE MAPPINGS OF ORDER αON THE BOUNDED STARLIKE CIRCULAR DOMAIN IN C^n 被引量:1
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作者 刘太顺 徐庆华 《Acta Mathematica Scientia》 SCIE CSCD 2017年第3期722-731,共10页
In this article, first, we establish the Fekete and Szeg inequality for an interesting subclass of biholomorphic functions in the open unit disk U. Second, we generalize this result to the bounded starlike circular do... In this article, first, we establish the Fekete and Szeg inequality for an interesting subclass of biholomorphic functions in the open unit disk U. Second, we generalize this result to the bounded starlike circular domain in C^n. The proofs of these results use some restrictive assumptions, which in the case of one complex variable are automatically satisfied. 展开更多
关键词 Fekete-Szeg problem starlike mappings of order α bounded starlike circular domain
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Fischer–Tropsch synthesis on impregnated cobalt-based catalysts:New insights into the effect of impregnation solutions and pH value 被引量:1
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作者 Chuang Xing Peipei Ai +6 位作者 Peipei Zhang Xinhua Gao Ruiqin Yang Noriyuki Yamane Jian Sun Prasert Reubroycharoen Noritatsu Tsubaki 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2016年第6期994-1000,共7页
The Co-based catalysts were prepared with different cobalt acetate solutions. Effects of p H value were studied deeply on Fischer–Tropsch synthesis(FTS) through a semi-batch reactor. Among all impregnation solutions(... The Co-based catalysts were prepared with different cobalt acetate solutions. Effects of p H value were studied deeply on Fischer–Tropsch synthesis(FTS) through a semi-batch reactor. Among all impregnation solutions(water, butanol, amyl alcohol, acetic acid, nitric acid and ammonium nitrate), the catalyst prepared by NH_4NO_3 solution showed the highest catalytic activity due to its small particle size and high reduction degree. However, the catalyst with the smallest particle size derived from water as impregnation solution exhibited low activity as well as high methane selectivity since it was difficult to be reduced and inactive in FTS. According to FT-IR spectra results, the low intensity of absorbed CO on the catalyst prepared from water solution resulted in low FTS activity. Whereas, the high activity of catalysts prepared from NH_4NO_3 solution could be explained by the high intensity of absorbed CO on the catalysts.The cobalt species on the catalysts prepared under lower p H conditions exhibited smaller particle size distribution as well as lower CO conversion than those prepared at higher p H value. 展开更多
关键词 Fischer–Tropsch synthesis Co catalyst pH value Impregnation solution
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Existence and asymptotic behavior for systems of nonlinear hyperbolic equations
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作者 YE Yao-jun 《Applied Mathematics(A Journal of Chinese Universities)》 SCIE CSCD 2015年第4期453-465,共13页
The initial-boundary value problem for a class of nonlinear hyperbolic equations system in bounded domain is studiedThe existence of global solutions for this problem is proved by constructing a stable set, and obtain... The initial-boundary value problem for a class of nonlinear hyperbolic equations system in bounded domain is studiedThe existence of global solutions for this problem is proved by constructing a stable set, and obtain the asymptotic stability of global solutions by means of a difference inequality. 展开更多
关键词 双曲型方程组 非线性 渐近稳定性 初边值问题 双曲方程组 解的存在性 差分不等式 有界域
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