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The burden of upper motor neuron involvement is correlated with the bilateral limb involvement interval in patients with amyotrophic lateral sclerosis:a retrospective observational study
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作者 Jieying Wu Shan Ye +2 位作者 Xiangyi Liu Yingsheng Xu Dongsheng Fan 《Neural Regeneration Research》 SCIE CAS 2025年第5期1505-1512,共8页
Amyotrophic lateral sclerosis is a rare neurodegenerative disease characterized by the involvement of both upper and lower motor neurons.Early bilateral limb involvement significantly affects patients'daily lives ... Amyotrophic lateral sclerosis is a rare neurodegenerative disease characterized by the involvement of both upper and lower motor neurons.Early bilateral limb involvement significantly affects patients'daily lives and may lead them to be confined to bed.However,the effect of upper and lower motor neuron impairment and other risk factors on bilateral limb involvement is unclear.To address this issue,we retrospectively collected data from 586 amyotrophic lateral sclerosis patients with limb onset diagnosed at Peking University Third Hospital between January 2020 and May 2022.A univariate analysis revealed no significant differences in the time intervals of spread in different directions between individuals with upper motor neuron-dominant amyotrophic lateral sclerosis and those with classic amyotrophic lateral sclerosis.We used causal directed acyclic graphs for risk factor determination and Cox proportional hazards models to investigate the association between the duration of bilateral limb involvement and clinical baseline characteristics in amyotrophic lateral sclerosis patients.Multiple factor analyses revealed that higher upper motor neuron scores(hazard ratio[HR]=1.05,95%confidence interval[CI]=1.01–1.09,P=0.018),onset in the left limb(HR=0.72,95%CI=0.58–0.89,P=0.002),and a horizontal pattern of progression(HR=0.46,95%CI=0.37–0.58,P<0.001)were risk factors for a shorter interval until bilateral limb involvement.The results demonstrated that a greater degree of upper motor neuron involvement might cause contralateral limb involvement to progress more quickly in limb-onset amyotrophic lateral sclerosis patients.These findings may improve the management of amyotrophic lateral sclerosis patients with limb onset and the prediction of patient prognosis. 展开更多
关键词 amyotrophic lateral sclerosis bilateral limb involvement Cox proportional hazards regression model horizontal spread restricted cubic spline analysis time interval upper motor neuron vertical spread
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Study of the Efficiency of Vertical Drains by an FEM Method in Soil Treatment for Road Projects: Case of the Development and Bitumination Works of the ROCADE Porto-Novo in Benin
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作者 Cheikh Diallo Diène Vitouley Kossi Ghyslain Joël +1 位作者 Mamadou Tine Apanda Mbongote Johnny 《Open Journal of Civil Engineering》 2024年第3期435-455,共21页
This article aims to study the efficiency of coupled vertical drains for the treatment of long-lasting compressible clay soils for the road project platform of the ring road of Porto Novo, capital of Benin. The experi... This article aims to study the efficiency of coupled vertical drains for the treatment of long-lasting compressible clay soils for the road project platform of the ring road of Porto Novo, capital of Benin. The experimental data allowed us to estimate a consolidation of 29% in 9 months, justifying the drainage of the soil. In order to study the efficiency of drainage, a FEM model was proposed simulating different scenarios. These include a drainless road, pavements equipped with vertical drains with meshes of 0.5 m 0.5 m, 1 m 1 m and 1.5 m 1.5 m respectively and horizontal drains. The results expressed in terms of variations in vertical stresses, effective stresses and shear deformations revealed significant variations in pavement performance depending on the mesh size of the vertical drains. The configuration with a mesh of 0.5 m 0.5 m showed the least deformations, thus indicating a reduction in deformations and better stress distribution. However, the other mesh configurations showed variable results, underlining the importance of choosing the right mesh for the specific project conditions. 展开更多
关键词 PAVEMENT vertical Drains horizontal Drains Modelling Plaxis2D ROCADE de Porto-Novo
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An Integrated Scheduling Algorithm for the Same Equipment Process Sequencing Based on the Root-Subtree Vertical and Horizontal Pre-Scheduling
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作者 Zhiqiang Xie Haikun Teng +1 位作者 Anak Agung Ayu Putri Ardyanti Xu Yu 《Computer Modeling in Engineering & Sciences》 SCIE EI 2023年第1期179-200,共22页
Given the existing integrated scheduling algorithms,all processes are ordered and scheduled overall,and these algorithms ignore the influence of the vertical and horizontal characteristics of the product process tree ... Given the existing integrated scheduling algorithms,all processes are ordered and scheduled overall,and these algorithms ignore the influence of the vertical and horizontal characteristics of the product process tree on the product scheduling effect.This paper presents an integrated scheduling algorithm for the same equipment process sequencing based on the Root-Subtree horizontal and vertical pre-scheduling to solve the above problem.Firstly,the tree decomposition method is used to extract the root node to split the process tree into several Root-Subtrees,and the Root-Subtree priority is set from large to small through the optimal completion time of vertical and horizontal pre-scheduling.All Root-Subtree processes on the same equipment are sorted into the stack according to the equipment process pre-start time,and the stack-top processes are combined with the schedulable process set to schedule and dispatch the stack.The start processing time of each process is determined according to the dynamic start processing time strategy of the equipment process,to complete the fusion operation of the Root-Subtree processes under the constraints of the vertical process tree and the horizontal equipment.Then,the root node is retrieved to form a substantial scheduling scheme,which realizes scheduling optimization by mining the vertical and horizontal characteristics of the process tree.Verification by examples shows that,compared with the traditional integrated scheduling algorithms that sort the scheduling processes as an overall,the integrated scheduling algorithmin this paper is better.The proposed algorithmenhances the process scheduling compactness,reduces the length of the idle time of the processing equipment,and optimizes the production scheduling target,which is of universal significance to solve the integrated scheduling problem. 展开更多
关键词 horizontal and vertical pre-scheduling the priority of the Root-Subtree the equipment process pre-start time the dynamic start time strategy of the equipment process
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Study on the Load Characteristics of Submerged Body Under Internal Solitary Waves on the Continental Shelf and Slope
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作者 LIU Qian CUI Jian +5 位作者 MEI Huan GAO Jun-liang WU Xiang-bai ZHANG Dai-yu ZHANG Rui-rui SHANG Xiao-dong 《China Ocean Engineering》 SCIE EI CSCD 2024年第5期809-820,共12页
Based on the high-quality observation data and the numerical simulation,the evolution characteristics of internal solitary waves(ISWs)and the load on the suspend submerged body are studied on the continental shelf and... Based on the high-quality observation data and the numerical simulation,the evolution characteristics of internal solitary waves(ISWs)and the load on the suspend submerged body are studied on the continental shelf and slope separately.The observed ISWs exhibit the first mode depression ISWs.The amplitudes of ISWs on the shelf and slope areas reach 50 m and 80 m,respectively.The upper layer velocity in the westward direction is about 0.8 m/s on the continental shelf and 0.9 m/s on the continental slope during the passing through of ISWs.The lower layer is dominated by the eastward compensating flow.In the vertical direction,the water in front of the wave flows downward,while the water behind the wave flows upward,and the maximum vertical velocity exceeds 0.2 m/s.Numerical simulation results show that the larger the amplitude of ISWs,the larger the load on the submerged body.The force on the submerged body by ISWs is dominated by the vertical force,and the corresponding maximum vertical forces on the continental shelf and slope are−25 kN and −27 kN.The submerged body is subjected to a large counterclockwise moment and the sudden change of the moment will also cause the submerged body to capsize.This paper not only gives a deeper understanding of the characteristics of ISWs from the deep continental slope to the shallow continental shelf,but also has a certain guiding value for the prediction of ISWs and for marine military activities. 展开更多
关键词 internal solitary waves submerged body CFD horizontal force vertical force MOMENT South China Sea
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Identification of the Caroline Plate boundary:constraints from magnetic anomaly
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作者 Yongtao Fu Guoliang Zhang +4 位作者 Wanyin Wang An Yang Tao He Zhangguo Zhou Xiao Han 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2024年第8期1-12,共12页
The Caroline Plate is located among the Pacific Plate,the Philippine Sea Plate,and the India Australia Plate,and plays a key role in controlling the spreading direction of the Philippine Sea Plate.The Caroline Submari... The Caroline Plate is located among the Pacific Plate,the Philippine Sea Plate,and the India Australia Plate,and plays a key role in controlling the spreading direction of the Philippine Sea Plate.The Caroline Submarine Plateau(or Caroline Ridge)and the Eauripik Rise on the south formed a remarkable T-shaped large igneous rock province,which covered the northern boundary between the Caroline Plate and the Pacific Plate.However,relationship between these tectonic units and magma evolution remains unclear.Based on magnetic data from the Earth Magnetic Anomaly Grid(2-arc-minute resolution)(V2),the normalized vertical derivative of the total horizontal derivative(NVDR-THDR)technique was used to study the boundary of the Caroline Plate.Results show that the northern boundary is a transform fault that runs 1400 km long in approximately 28 km wide along the N8°in E-W direction.The eastern boundary is an NNW-SSE trending fault zone and subduction zone with a width of tens to hundreds of kilometers;and the north of N4°is a fracture zone of dense faults.The southeastern boundary may be the Lyra Trough.The area between the southwestern part of the Caroline Plate and the Ayu Trough is occupied by a wide shear zone up to 100 km wide in nearly S-N trending in general.The Eauripik transform fault(ETF)in the center of the Caroline Plate and the fault zones in the east and west basins are mostly semi-parallel sinistral NNW-SSE–trending faults,which together with the eastern boundary Mussau Trench(MT)sinistral fault,the northern Caroline transform fault(CTF),and the southern shear zone of the western boundary,indicates the sinistral characteristics of the Caroline Plate.The Caroline hotspot erupted in the Pacific Plate near the CTF and formed the west Caroline Ridge,and then joined with the Caroline transform fault at the N8°.A large amount of magma erupted along the CTF,by which the east Caroline Ridge was formed.At the same time,a large amount of magma developed southward via the eastern branch of the ETF,forming the northern segment of the Eauripik Rise.Therefore,the magmatic activity of the T-shaped large igneous province is obviously related to the fault structure of the boundary faults between the Caroline Plate and Pacific Plate,and the active faults within the Caroline Plate. 展开更多
关键词 Caroline Plate magnetic anomaly normalized vertical derivative of the total horizontal derivative plate boundary Caroline Ridge Eauripik Rise
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Separate-layer balanced waterflooding development technology for thick and complex carbonate reservoirs in the Middle East
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作者 SONG Xinmin LI Yong +6 位作者 LI Fengfeng YI Liping SONG Benbiao ZHU Guangya SU Haiyang WEI Liang YANG Chao 《Petroleum Exploration and Development》 SCIE 2024年第3期661-673,共13页
Based on the waterflooding development in carbonate reservoirs in the Middle East,in order to solve the problem of the poor development effects caused by commingled injection and production,taking the thick bioclastic... Based on the waterflooding development in carbonate reservoirs in the Middle East,in order to solve the problem of the poor development effects caused by commingled injection and production,taking the thick bioclastic limestone reservoirs of Cretaceous in Iran-Iraq as an example,this paper proposes a balanced waterflooding development technology for thick and complex carbonate reservoirs.This technology includes the fine division of development units by concealed baffles and barriers,the combination of multi well type and multi well pattern,and the construction of balanced water injection and recovery system.Thick carbonate reservoirs in Iran-Iraq are characterized by extremely vertical heterogeneity,development of multi-genesis ultra-high permeability zones,and highly concealed baffles and barriers.Based on the technologies of identification,characterization,and sealing evaluation for concealed baffles and barriers,the balanced waterflooding development technology is proposed,and three types of balanced waterflooding development modes/techniques are formed,namely,conventional stratigraphic framework,fine stratigraphic framework,and deepened stratigraphic framework.Numerical simulations show that this technology is able to realize a fine and efficient waterflooding development to recover,in a balanced manner,the reserves of thick and complex carbonate reservoirs in Iran and Iraq.The proposed technology provides a reference for the development optimization of similar reservoirs. 展开更多
关键词 the Middle East thick carbonate reservoir vertical heterogeneity concealed baffle and barrier sealing separated development units balanced waterflooding
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Zeno and the Wrong Understanding of Motion—A Philosophical-Mathematical Inquiry into the Concept of Finitude as a Peculiarity of Infinity
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作者 Andreas Herberg-Rothe 《Journal of Applied Mathematics and Physics》 2024年第3期912-929,共18页
In contrast to the solutions of applied mathematics to Zeno’s paradoxes, I focus on the concept of motion and show that, by distinguishing two different forms of motion, Zeno’s apparent paradoxes are not paradoxical... In contrast to the solutions of applied mathematics to Zeno’s paradoxes, I focus on the concept of motion and show that, by distinguishing two different forms of motion, Zeno’s apparent paradoxes are not paradoxical at all. Zeno’s paradoxes indirectly prove that distances are not composed of extensionless points and, in general, that a higher dimension cannot be completely composed of lower ones. Conversely, lower dimensions can be understood as special cases of higher dimensions. To illustrate this approach, I consider Cantor’s only apparent proof that the real numbers are uncountable. However, his widely accepted indirect proof has the disadvantage that it depends on whether there is another way to make the real numbers countable. Cantor rightly assumes that there can be no smallest number between 0 and 1, and therefore no beginning of counting. For this reason he arbitrarily lists the real numbers in order to show with his diagonal method that this list can never be complete. The situation is different if we start with the largest number between 0 and 1 (0.999…) and use the method of an inverted triangle, which can be understood as a special fractal form. Here we can construct a vertical and a horizontal stratification with which it is actually possible to construct all real numbers between 0 and 1 without exception. Each column is infinite, and each number in that column is the starting point of a new triangle, while each row is finite. Even in a simple sine curve, we experience finiteness with respect to the y-axis and infinity with respect to the x-axis. The first parts of this article show that Zeno’s assumptions contradict the concept of motion as such, so it is not surprising that this misconstruction leads to contradictions. In the last part, I discuss Cantor’s diagonal method and explain the method of an inverted triangle that is internally structured like a fractal by repeating this inverted triangle at each column. The consequence is that we encounter two very different methods of counting. Vertically it is continuous, horizontally it is discrete. While Frege, Tarski, Cantor, Gödel and the Vienna Circle tried to derive the higher dimension from the lower, a procedure that always leads to new contradictions and antinomies (Tarski, Russell), I take the opposite approach here, in which I derive the lower dimension from the higher. This perspective seems to fail because Tarski, Russell, Wittgenstein, and especially the Vienna Circle have shown that the completeness of the absolute itself is logically contradictory. For this reason, we agree with Hegel in assuming that we can never fully comprehend the Absolute, but only its particular manifestations—otherwise we would be putting ourselves in the place of the Absolute, or even God. Nevertheless, we can understand the Absolute in its particular expressions, as I will show with the modest example of the triangle proof of the combined horizontal and vertical countability of the real numbers, which I developed in rejection of Cantor’s diagonal proof. . 展开更多
关键词 Zeno False Assumptions about Motion Finitude INFINITY Cantor’s Diagonal Method Inverted Triangle as a Different Method vertical and horizontal Dimensions Quantum theory Relativity of Space and Time Depending on Velocity
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A new edge recognition technology based on the normalized vertical derivative of the total horizontal derivative for potential field data 被引量:95
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作者 Wang Wanyin Pan Yu Qiu Zhiyun 《Applied Geophysics》 SCIE CSCD 2009年第3期226-233,299,共9页
Edge detection and enhancement techniques are commonly used in recognizing the edge of geologic bodies using potential field data. We present a new edge recognition technology based on the normalized vertical derivati... Edge detection and enhancement techniques are commonly used in recognizing the edge of geologic bodies using potential field data. We present a new edge recognition technology based on the normalized vertical derivative of the total horizontal derivative which has the functions of both edge detection and enhancement techniques. First, we calculate the total horizontal derivative (THDR) of the potential-field data and then compute the n-order vertical derivative (VDRn) of the THDR. For the n-order vertical derivative, the peak value of total horizontal derivative (PTHDR) is obtained using a threshold value greater than 0. This PTHDR can be used for edge detection. Second, the PTHDR value is divided by the total horizontal derivative and normalized by the maximum value. Finally, we used different kinds of numerical models to verify the effectiveness and reliability of the new edge recognition technology. 展开更多
关键词 potential field data edge recognition edge enhancement total horizontal derivative normalized vertical derivative
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Sensitivity of WRF simulated typhoon track and intensity over the South China Sea to horizontal and vertical resolutions 被引量:6
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作者 Zhiyuan Wu Changbo Jiang +2 位作者 Bin Deng Jie Chen Xiaojian Liu 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2019年第7期74-83,共10页
To determine the grid resolutions of the WRF model in the typhoon simulation,some sensitivity analysis of horizontal and vertical resolutions in different conditions has been carried out.Different horizontal resolutio... To determine the grid resolutions of the WRF model in the typhoon simulation,some sensitivity analysis of horizontal and vertical resolutions in different conditions has been carried out.Different horizontal resolutions(5,10,20,30 km),nesting grids(15 and 5 km),different vertical resolutions(35-layers,28-layers,20-layers)and different top maximum pressures(1 000,2 000,3 500,5 000 Pa)had been used in the mesoscale numerical model WRF to simulate the Typhoon Kai-tak.The simulation results of typhoon track,wind speed and sea level pressure at different horizontal and vertical resolutions have been compared and analyzed.The horizontal and vertical resolutions of the model have limited effect on the simulation effect of the typhoon track.Different horizontal and vertical resolutions have obvious effects on typhoon strength(defined by wind speed)and intensity(defined by sea level pressure,SLP),especially for sea level pressure.The typhoon intensity simulated by the high-resolution model is closer to the real situation and the nesting grids can improve computational accuracy and efficiency.The simulation results affected by vertical resolution using 35-layers is better than the simulation results using 20-layers and 28-layers simulations.Through comparison and analysis,the horizontal and vertical resolutions of WRF model are finally determined as follows:the two-way nesting grid of 15 and 5 km is comprehensively determined,and the vertical layers is 35-layers,the top maximum pressure is 2 000 Pa. 展开更多
关键词 sensitivity analysis TYPHOON track and INTENSITY horizontal and vertical RESOLUTIONS TYPHOON Kai-tak WRF
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Experimental Study on Bubble Pulse Features Under the Combined Action of Horizontal and Vertical Walls 被引量:5
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作者 王诗平 初文华 张阿漫 《China Ocean Engineering》 SCIE EI CSCD 2014年第3期293-301,共9页
The pulse features of a bubble have a close connection with the boundary condition. When a bubble moves near a rigid wall, it will be attracted by the Bjerknes force of the wall, and a jet pointing at the wall will be... The pulse features of a bubble have a close connection with the boundary condition. When a bubble moves near a rigid wall, it will be attracted by the Bjerknes force of the wall, and a jet pointing at the wall will be generated. In real application, the bubble may move under the combined action of walls in different directions when it forms at the corner of a pipe or at the bottom of a dam. The motion of the bubble shows complex and nonlinear characteristics under these conditions. In order to investigate the bubble pulse features near complex walls, a horizontal wall and a vertical wall are put into the experimental water tank synchronously, and an electric circuit with 200 voltages is designed to generate discharge bubbles, and then experimental study on the bubble pulse features under the combined action of horizontal and vertical walls is carried out. The influences of the combined action of two walls on the bubble shape, pulse period, moving trace and inside jet are obtained by changing the distances from bubble center to the two walls. It aims at providing references for the relevant theoretical and numerical research. 展开更多
关键词 BUBBLE combined action horizontal and vertical walls experimental study
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Estimating the site effects in Luoyang basin using horizontal-to-vertical spectral ratio method from a short-period dense array 被引量:3
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作者 Yujuan Tan Yunhao Wei +1 位作者 Yonghong Duan Fuyun Wang 《Earthquake Science》 CSCD 2018年第5期272-280,共9页
The influence of local site effects on seismic ground motions is an important issue in seismic hazard assessment and earthquake resistant design. Determining site effects in densely populated cities built on basins ca... The influence of local site effects on seismic ground motions is an important issue in seismic hazard assessment and earthquake resistant design. Determining site effects in densely populated cities built on basins can help to reduce the earthquake hazard. Site effects of Luoyang basin are estimated by the horizontal-to-vertical spectral ratio(HVSR) method using ambient noise records from a short-period dense array. The sites in Luoyang basin are sorted into three types according to the pattern of the HVSR curves. There are cases with a single clear peak, two clear peaks, and an unclear low frequency peak or multiple peaks, which correspond to there being one large impedance contrast interface, two large interfaces, and a moderate one beneath the sites, respectively. The site effects characterized by fundamental frequency from HVSR curves are affected by underlying sedimentary layers and depth of sedimentary basement. According to our results, the existence of thick sediment layer obviously lowers the fundamental frequency to the period range from 2 to 4 s in the downtown area of Luoyang city. The ground motion will amplify when through the sites and the buildings with height of 20–50 floors can resonate at the similar frequency domain. Site effects estimation using HVSR method from a short-period dense array is an effective technique in areas of moderate seismic risk where strong motion recordings are lacking, such as the Luoyang basin. 展开更多
关键词 site effects horizontal to vertical spectral ratio dense array Luoyang basin
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Separation performance of horizontal and vertical polyethersulfone hollow fiber UF modules 被引量:1
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作者 Alsalhy Qusay Fadhel 许振良 杨晓天 《Journal of Shanghai University(English Edition)》 CAS 2006年第2期173-178,共6页
The effect of hollow fiber module positions ( horizontal and vertical) on separation performance for PVA solution by using polyethersulfone (PES) hollow fiber ultrafiltration (UF) membrane with the molecular wei... The effect of hollow fiber module positions ( horizontal and vertical) on separation performance for PVA solution by using polyethersulfone (PES) hollow fiber ultrafiltration (UF) membrane with the molecular weight cut-off (MWCO) 30 000 has been discussed. Experimental results illustrated that the suitable operation conditions for PVA solution were as follows: trans-membrane pressure 2.1 bar, solution temperature 75℃ and feed velocity 0.32 m/s. Under these suitable operation conditions, the permeate flux is from 36.8 L/(m^2 ·h·bar) to 42.9 L/(m^2 ·h·bar) for the horizontal module and from 39.8 L/(m^2 ·h·bar) to 66.6 L/(m^2 ·h·bar) for the vertical module. Besides, the Separation performance of PES hollow fiber UF membrane was better by using vertical hollow fiber module than by using horizontal hollow fiber module. When the trans-membrane pressure increased from 1 bar to 2.1 bar, solution temperature from 50 ℃ to 75 ℃, feed solution velocity from 0.16 m/s to 0.32 m/s, the PVA rejection would increase from 95.8% to 99.7%, 95.4 96 to 98.6 %, 95.8 96 to 99.2 96 for horizontal module respectively, and from 98.8 96 to 99.8 %, 98.6 96 to 99.4 96, 98.5 96 to 99.4 96 for vertical module respectively. Therefore, PVA rejection in PES hollow fiber UF process was more than 98.5 96 for vertical module, and it is suitable for PVA recovery from wastewater. 展开更多
关键词 hollow fiber UF membrane POLYEtheRSULFONE polyvinyl alcohol horizontal module vertical module.
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The Dynamic Behavior of a Discrete Vertical and Horizontal Transmitted Disease Model under Constant Vaccination 被引量:7
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作者 Mingshan Li Xiumin Liu Xiaoliang Zhou 《International Journal of Modern Nonlinear Theory and Application》 2016年第4期171-184,共15页
In this paper, a class of discrete vertical and horizontal transmitted disease model under constant vaccination is researched. Under the hypothesis of population being constant size, the model is transformed into a pl... In this paper, a class of discrete vertical and horizontal transmitted disease model under constant vaccination is researched. Under the hypothesis of population being constant size, the model is transformed into a planar map and its equilibrium points and the corresponding eigenvalues are solved out. By discussing the influence of coefficient parameters on the eigenvalues, the hyperbolicity of equilibrium points is determined. By getting the equations of flows on center manifold, the direction and stability of the transcritical bifurcation and flip bifurcation are discussed. 展开更多
关键词 vertical and horizontal Transmission VACCINATION Center Manifold Transcritical Bifurcation Flip Bifurcation
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On the physical significance and use of a set of horizontal and vertical helicity budget equations
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作者 FU Shenming MAI Zi +1 位作者 SUN Jianhua TANG Huan 《Atmospheric and Oceanic Science Letters》 CSCD 2019年第6期417-423,共7页
For better understanding the variation of helicity and its governing mechanisms,based on the primary momentum equation under the local Cartesian coordinate,a set of horizontal and vertical helicity equations are deriv... For better understanding the variation of helicity and its governing mechanisms,based on the primary momentum equation under the local Cartesian coordinate,a set of horizontal and vertical helicity equations are derived in this study.On this basis,a storm-relative helicity budget equation is derived,the main factors that govern the variation of helicity are discussed,and the key mechanisms underlying the helicity variation are illustrated by using schematic images.Both scale analysis and real case diagnosis are used to compare the relative importance of di erent factors on the variation of helicity.For a meso-α system,it is found that:(i)horizontal helicity is much larger than vertical helicity,and they show signi cantly di erent variation mechanisms;(ii)for the vertical helicity,the vertical perturbation pressure gradient force,buoyancy,the diver-gence-related e ect,and the conversion between vertical and horizontal helicity govern its variation(whereas,the conversion is negligible for the evolution of horizontal helicity);and(iii)baroclinity is crucial for the variation of horizontal helicity,but it is only of secondary importance for the vertical helicity variation. 展开更多
关键词 horizontal helicity vertical helicity baroclinity kinetic energy
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Impacts of Horizontal and Vertical Resolutions on the Microphysical Structure and Boundary Layer Fluxes of Typhoon Hato(2017)
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作者 ZHAO Yang-jie LI Jiang-nan +1 位作者 LI Fang-zhou RUAN Zi-xi 《Journal of Tropical Meteorology》 SCIE 2021年第1期10-23,共14页
We set four sets of simulation experiments to explore the impacts of horizontal resolution(HR)and vertical resolution(VR)on the microphysical structure and boundary layer fluxes of tropical cyclone(TC)Hato(2017).The s... We set four sets of simulation experiments to explore the impacts of horizontal resolution(HR)and vertical resolution(VR)on the microphysical structure and boundary layer fluxes of tropical cyclone(TC)Hato(2017).The study shows that higher HR tends to strengthen TC.Increasing VR in the upper layers tends to weaken TC,while increasing VR in the lower layers tends to strengthen TC.Simulated amounts of all hydrometeors were larger with higher HR.Increasing VR at the upper level enhanced the mixing ratios of cloud ice and cloud snow,while increasing VR at the lower level elevated the mixing ratios of graupel and rainwater.HR has greater impact on the distributions of hydrometeors.Higher HR has a more complete ring structure of the eyewall and more concentrated hydrometeors along the cloud wall.Increasing VR at the lower level has little impact on the distribution of TC hydrometeors,while increasing VR at the upper level enhances the cloud thickness of the eyewall area.Surface latent heat flux(SLHF)is influenced greatly by resolution.Higher HR leads to larger water vapor fluxes and larger latent heat,which would result in a stronger TC.A large amount of false latent heat was generated when HR was too high,leading to an extremely strong TC,VR has a smaller impact on SLHF than HR.But increasing VR at the upper-level reduces the SLHF and weakens TC,and elevating VR at the lower-level increases the SLHF and strengthens TC.The changes in surface water vapor flux and SLHF were practically identical and the simulation results were improved when HR and VR were more coordinated.The friction velocity was greater with higher VR.Enhancing VR at the lower level increased the friction velocity,while increasing VR at the upper level reduced it. 展开更多
关键词 tropical cyclone horizontal resolution vertical resolution WRF
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The Vertical Deformation and Horizontal Displacement Fields,Movement, and Seismicity of the Island Arc Tectonics
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作者 Luo Wei,Luo Zhuoli,and Chen ShangpingNational Center for Seismic Data and Informanon,SSB,Beijing 100045,China Center for Analysis and Prediction,SSB,Beijing 100036,China 《Earthquake Research in China》 1996年第3期25-36,共12页
In this work,the vertical deformation,horizontal displacement,and stress fields of arcuate tectonics are theoretically derived from the horizontal tectonic stress; then the characteristics of tectonic movement,seismic... In this work,the vertical deformation,horizontal displacement,and stress fields of arcuate tectonics are theoretically derived from the horizontal tectonic stress; then the characteristics of tectonic movement,seismicity,and focal mechanism of arcuate tectonics of the entire world are explained.It is pointed out that the island arc and other arcuate tectonics are gradually developed under the displacement and stress fields of the arcuate tectonics and that the under-thrusting action of the ocean plate is secondary.The distance formulas between the volcanic arc and the trench are suggested and also that theoretical results are consistent with actual data. 展开更多
关键词 Island arc ARCUATE TECTONICS vertical deformation FIELD horizontal displacement FIELD TECTONIC MOVEMENT
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Experimental and Theoretical Investigation of Wave Forces on APartially-Perforated Caisson Breakwater with A Rock-Filled Core 被引量:6
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作者 刘勇 李玉成 +1 位作者 滕斌 姜俊杰 《China Ocean Engineering》 SCIE EI 2006年第2期179-198,共20页
The total horizontal and vertical forces acting on a partially-perforated caisson breakwater and their phase difference are investigated in this study. The perforated breakwater sits on the rubble tilled foundation, a... The total horizontal and vertical forces acting on a partially-perforated caisson breakwater and their phase difference are investigated in this study. The perforated breakwater sits on the rubble tilled foundation, and has a rock-filled core. An analytical solution is developed based on the eigenfunction expansion and matching method to solve the wave field around the breakwater. The finite element method is used for simulating the wave-induced tlow in the rabble-filled foundation. Experiments are also conducted to study the wave forces on the perforated caissons. Numerical predictions of the present model are compared with experimental resuhs. The phase differences between the total horizontal and vertical forces are particularly analyzed by means of experimental and numerical results. The major factors that affect the wave forces are examined. 展开更多
关键词 partially-perforated caisson rock-fill core horizontal force vertical force phase difference
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A parameterization scheme of vertical mixing due to inertial internal wave breaking in the ocean general circulation model 被引量:4
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作者 FAN Zhisong SHANG Zhenqi +2 位作者 ZHANG Shanwu HU Ruijin LIU Hailong 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2015年第1期11-22,共12页
Based on the theoretical spectral model of inertial internal wave breaking (fine structure) proposed previ- ously, in which the effects of the horizontal Coriolis frequency component f-tilde on a potential isopycnal... Based on the theoretical spectral model of inertial internal wave breaking (fine structure) proposed previ- ously, in which the effects of the horizontal Coriolis frequency component f-tilde on a potential isopycnal are taken into account, a parameterization scheme of vertical mixing in the stably stratified interior be- low the surface mixed layer in the ocean general circulation model (OGCM) is put forward preliminarily in this paper. Besides turbulence, the impact of sub-mesoscale oceanic processes (including inertial internal wave breaking product) on oceanic interior mixing is emphasized. We suggest that adding the inertial inter- hal wave breaking mixing scheme (F-scheme for short) put forward in this paper to the turbulence mixing scheme of Canuto et al. (T-scheme for short) in the OGCM, except the region from 15°S to 15°N. The numeri- cal results ofF-scheme by usingWOA09 data and an OGCM (LICOM, LASG/IAP climate system ocean model) over the global ocean are given. A notable improvement in the simulation of salinity and temperature over the global ocean is attained by using T-scheme adding F-scheme, especially in the mid- and high-latitude regions in the simulation of the intermediate water and deep water. We conjecture that the inertial internal wave breaking mixing and inertial forcing of wind might be one of important mechanisms maintaining the ventilation process. The modeling strength of the Atlantic meridional overturning circulation (AMOC) by using T-scheme adding F-scheme may be more reasonable than that by using T-scheme alone, though the physical processes need to be further studied, and the overflow parameterization needs to be incorporated. A shortcoming in F-scheme is that in this paper the error of simulated salinity and temperature by using T-scheme adding F-scheme is larger than that by using T-scheme alone in the subsurface layer. 展开更多
关键词 vertical mixing inertial internal wave fine structure horizontal Coriolis frequency component ocean general circulation model
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Determination of active units with different kinematic property and their activity pattern in North China based on the data from GPS remeasurements 被引量:2
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作者 杨国华 韩月萍 张凤兰 《Acta Seismologica Sinica(English Edition)》 CSCD 2001年第1期1-11,共11页
Based on the high-accuracy data obtained from the GPS measurements carried out in 1992, 1995 and 1996, the isochronous active units with different kinematic property inside the North China area have been distinguished... Based on the high-accuracy data obtained from the GPS measurements carried out in 1992, 1995 and 1996, the isochronous active units with different kinematic property inside the North China area have been distinguished, 4 active units and 1 transition zone with distinct differential movement have been determined. They are Ordos-Yinshan unit, Yanshan unit, Shanxi-Hebei-Shandong (Jin-Ji-Lu) unit, Jiaodong-Liaoning-Shandong (Jiao-Liao-Lu) unit and Yanshan-Hebei (Yan-Ji) transition zone. The relative movements among the neighboring units in this period have been given. ① The compressive movement between Ordos-Yinshan unit and Yanshan unit is not obvious with an amount of 0.4(1.3 mm/a.②in-Ji-Lu unit moves E40(S off the Ordos-Yinshan unit and the magnitude is 4.4(1.0 mm/a. ③elative to the Yan-Ji transition zone of differential movement, Yanshan unit shifts W38(N with a value of 2.4(1.3 mm/a and Jin-Ji-Lu unit moves eastward 35( by south with an amount of 2.3(0.9 mm/a. ④Jin-Ji-Lu unit has a tensional left-lateral movement of 4.7(1.4 mm/a in the direction of E37(S relative to Yanshan unit. ⑤ Some area near Tanlu belt which is located in the southern part of Jin-Ji-Lu block has a southward movement 14( by west with a magnitude of 1.5(1.1 mm/a off the Jin-Ji-Lu unit. ⑥ Relative to Jin-Ji-Lu unit, Jiao-Liao-Lu unit has a trend of clockwise movement with a tensional right-lateral motion at the north end which neighbors Yanshan unit and a compressive motion at the south end. It should be noted that the errors given in the paper are obtained based on the divergence among the displacements of the sites in the unit, rather than the value calculated from the displacement error of the sites. The analyzed results indicate that: ① Shanxi tectonic zone and Yan-Ji transition zone are the major tectonic active zones to show the frame and magnitude of interior relative movement in North China area, and others are the secondary tectonic active zones; ② The complete horizontal deformation in the North China area is not homogeneous nor successive; ③ The kinetic model of North China area might be (mantle dragging plus boundary coupling(. 展开更多
关键词 GPS measurement North China area active unit horizontal movement deformation mechanism
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Detecting the presence of natural forests using airborne laser scanning data
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作者 Marie-Claude Jutras-Perreault Terje Gobakken +1 位作者 Erik Næsset Hans OleØrka 《Forest Ecosystems》 SCIE CSCD 2023年第6期668-680,共13页
Centuries of forest exploitation have caused significant loss of natural forests in Europe,leading to a decline in populations for many species.To prevent further loss in biodiversity,the Norwegian government has set ... Centuries of forest exploitation have caused significant loss of natural forests in Europe,leading to a decline in populations for many species.To prevent further loss in biodiversity,the Norwegian government has set a target of protecting 10%of the forested area.However,recent data from the National Forest Inventory(NFI)reveals that less than 2%of Norway's forested area consists of natural forests.To identify forests with high conservation value,we used vertical and horizontal variables derived from airborne laser scanning(ALS)data,along with NFI plot measurements.Our study aimed to predict the presence of natural forests across three counties in southeastern Norway,using three different definitions:pristine,near-natural,and semi-natural forests.Natural forests are scarce,and their underrepresentation in field reference data can compromise the accuracy of the predictions.To address this,we assessed the potential gain of including additional field data specifically targeting natural forests to achieve a better balance in the dataset.Additionally,we examined the impact of stratifying the data by dominant tree species on the performance of the models.Our results revealed that semi-natural forests were the most accurately predicted,followed by near-natural and pristine forests,with Matthews correlation coefficient values of 0.32,0.24,and 0.17,respectively.Including additional field data did not improve the predictions.However,stratification by species improved the accuracy of predictions for near-natural and semi-natural forests,while reducing accuracy for pristine forests.The use of horizontal variables did not improve the predictions.Our study demonstrates the potential of ALS data in identifying forests with high conservation value.It provides a basis for further research on the use of ALS data for the detection and conservation of natural forests,offering valuable insights to guide future forest preservation efforts. 展开更多
关键词 Natural forest ALS NATURALNESS vertical variables horizontal variables BIODIVERSITY Forest condition Ecosystem services
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