According to the design specifications,the construction of extended piles involves traversing the tunnel’s upper region and extending to the underlying rock layer.To address this challenge,a subterranean transfer str...According to the design specifications,the construction of extended piles involves traversing the tunnel’s upper region and extending to the underlying rock layer.To address this challenge,a subterranean transfer structure spanning multiple subway tunnels was proposed.Deliberating on the function of piles in the transfer structure as springs with axial and bending stiffness,and taking into account the force balance and deformation coordination conditions of beams and plates within the transfer structure,we established a simplified mechanical model that incorporates soil stratification by combining it with the Winkler elastic foundation beam model.The resolved established simplifiedmechanicalmodel employed finite difference technology and the Newton-Simpsonmethod,elucidating the mechanical mechanism of the transfer structure.The research findings suggest that the load carried by the upper structural columns can be transferred to the pile foundation beneath the beams through the transfer structure,subsequently reaching the deep soil layer and ensuring minimal impact on adjacent tunnels.The established simplified analysis method can be used for stress analysis of the transfer structure,concurrently considering soil stratification,pile foundation behavior,and plate action.The pile length,pile section size,and beam section size within the transfer structure should account for the characteristics of the upper load,ensuring an even distribution of the beam bending moment.展开更多
This article is based on a recent model specifically defining magnetic field values around electrical wires. With this model, calculations of field around parallel wires were obtained. Now, this model is extended with...This article is based on a recent model specifically defining magnetic field values around electrical wires. With this model, calculations of field around parallel wires were obtained. Now, this model is extended with the new concept of magnetic equipotential surface to magnetic field curves around crossing wires. Cases of single, double, and triple wires are described. Subsequent article will be conducted for more general scenarios where wires are neither infinite nor parallel.展开更多
As a world-widely popular poem,Tennyson's Crossing the Bar attracts more and more people to cherish it.And this paper aims at translating it in a new way,and analyzing it in a fully scientific way.
Unicellular gametophytes of Undaria pinnatifida (Harv.) Sur. were isolated in Qingdao, P. R. China in April 1993 and in Tokushima, southem Japan in March 1995. Diferent intraspecific crossings by using unicellular mal...Unicellular gametophytes of Undaria pinnatifida (Harv.) Sur. were isolated in Qingdao, P. R. China in April 1993 and in Tokushima, southem Japan in March 1995. Diferent intraspecific crossings by using unicellular male and female gametophytes were successfully undertaken in Sept. of 1995 in Qingdao.Sporophytes were transplanted to two different locations for open an cultivation. One was at Zhanqiao (ZQ) Bay where the water current was slower than that of another location - Taipingjiao(TPJ). A total of218 adult sporophytes were harvested on January 12 and 18 from TPJ and ZQ repectively. For eacncombination, 10 sporophytes un cultivated. Analysis of the mprpholgical characteristics of adult spprophytes indicated that the longest length between two bases of the serration of pinnate bldes (W2) is a morphological characteristic that can be transferred from the parent plant to the next generations regardless of environmental variations. There was evidence that W2 was apparently determined by sex-linked factors, i.e, by male parental grametophyte.. Sporophytes from certain crossing combinations showed more vigorous growth than those from other crossing combinations. It is therrfore possible to select grametophyte strains which can be used as parental gametophytes for the seeding production of sporophytes with more vigorous growth within shorter cultivation period. The morphology of hybrids from a Qingdao strain and a Tokushima cultivated strain resembled that of both parental plants in frond feaures (wrinkled or smooth) and W2. Sporophyll formation also varied with strains. The fact that adult sporophytes resulting from the same crossing combinations have identical morphological characteristics under the same environmental conditions indicates the possibility of a new way to select strains which are expected to be ideal for commerical production by purposely selecting, propagating, and seeding unicellular gametophytes for sporeing production through freeliving techniques of gametophytes.展开更多
The cellular automaton model is suggested to describe the traffic-flow at the grade roundabout crossing. After the simulation with computer, the fundamental properties of this model have been revealed. Analysing this ...The cellular automaton model is suggested to describe the traffic-flow at the grade roundabout crossing. After the simulation with computer, the fundamental properties of this model have been revealed. Analysing this kind of road structure, this paper transforms the grade roundabout crossing with inner-roundabout-lane and outer-roundabout-lane into a configuration with many bottlenecks. Because of the self-organization, the traffic flow remains unblocked under a certain vehicle density. Some results of the simulation are close to the actual design parameter.展开更多
In this paper,the energy spectrum of the two-photon Jaynes-Cummings model(TPJCM) is calculated exactly in the non-rotating wave approximation(non-RWA),and we study the level-crossing problem by means of fidelity.A...In this paper,the energy spectrum of the two-photon Jaynes-Cummings model(TPJCM) is calculated exactly in the non-rotating wave approximation(non-RWA),and we study the level-crossing problem by means of fidelity.A narrow peak of the fidelity is observed at the level-crossing point,which does not appear at the avoided-crossing point.Therefore fidelity is perfectly suited for detecting the level-crossing point in the energy spectrum.展开更多
We present an edge crossing minimization algorithm for hierarchical graphs based on genetic algorithms, and comparing it with some heuristic algorithms. The proposed algorithm is more efficient and has the following a...We present an edge crossing minimization algorithm for hierarchical graphs based on genetic algorithms, and comparing it with some heuristic algorithms. The proposed algorithm is more efficient and has the following advantages: the frame of the algorithms is unified, the method is simple, and its implementation and revision are easy.展开更多
Crossing Brookly Ferry is one of the most representative masterpieces composed by Walt Wiltman. In this pieces of writing, ones of the characteristics in this poem: optimism and unconventionality in its form are expre...Crossing Brookly Ferry is one of the most representative masterpieces composed by Walt Wiltman. In this pieces of writing, ones of the characteristics in this poem: optimism and unconventionality in its form are expressed in details.展开更多
Objective:To compare laparoscopic Anderson-Hynes pyeloplasty(LAHP)and retroperitoneal laparoscopic YV-pyeloplasty(LRYVP)in ureteropelvic junction obstruction(UPJ)in presence of a crossing vessels(CV).Methods:Our datab...Objective:To compare laparoscopic Anderson-Hynes pyeloplasty(LAHP)and retroperitoneal laparoscopic YV-pyeloplasty(LRYVP)in ureteropelvic junction obstruction(UPJ)in presence of a crossing vessels(CV).Methods:Our database showed 380 UPJO-cases,who underwent laparoscopic retroperitoneal surgery during the last 2 decades including 206 non-dismembered LRYVP,157 dismembered pyeloplasties LAHP,and 17 cases of laparoscopic ureterolysis.Among them 198 cases were suitable for a matched-pair(2:1)analysis comparing laparoscopic retroperitoneal non-dismembered LRYVP(Group 1,n Z 131)and dismembered LAHP(Group 2,n Z 67)in presence of a crossing vessel.Patients were matched according to age,gender,kidney functions,and obstruction grade.Complications were graded according to modified Clavien-classification.Results:Comparative data were similar between both groups(LRYVP vs.LAHP)including mean operating time(112 min vs.114 min),complication rates(4.2%vs.7.3%)mainly Grade 1e2 according to Clavien classification,and success rates(90%vs.89%).These results reflected in the reviewed literature indicate that LRYVP provides the advantage of minimal dissection in case of CV with similar outcome.However,redundant pelvis and anteriorly crossing vessels still require a dismembered pyeloplasty LAHP.Conclusion:LRYVP has achieved similar results compared with the previous golden standard of open surgery,especially in case of crossing vessels apart from presence of a redundant pelvis or anteriorly crossing vessel.This can be further improved when using the small access retroperitoneoscopic technique respectively mini-laparoscopy.展开更多
Fifteen capsicum combinations were made with 6 parents by (1/2)n(n-1) diallel crossing. Genetic parameters in the resistance to TMV, CMV, phytophthora blight, bacterial spot of these combinations were studied by H...Fifteen capsicum combinations were made with 6 parents by (1/2)n(n-1) diallel crossing. Genetic parameters in the resistance to TMV, CMV, phytophthora blight, bacterial spot of these combinations were studied by Hayman. The results indicated that the resistance to TMV, CMV and bacterial spot conformed genetically to the “additive-dominant” model but the resistance to phytophthora blight did not and significant epistatic dominance effect existed in it. F1 hybrid's resistance to CMV was controlled by homozygous dominant gene (s), but resistance to bacterial spot by heterozygous one (s). There were little, or no sum of dominant effect and genomes controlling the dominant expression of F1 hybrids in its phytophthora blight resistance.展开更多
This paper presents a cellular automaton traffic flow model with an open boundary condition to describe the traffic flow at a roundabout crossing with an inner roundabout lane and an outer roundabout lane. The simulat...This paper presents a cellular automaton traffic flow model with an open boundary condition to describe the traffic flow at a roundabout crossing with an inner roundabout lane and an outer roundabout lane. The simulation results show that the boundary condition, bottlenecks and the self-organization affect the traffic flow at the roundabout crossing. Because of the effect of bottlenecks, jams easily appear on the inner roundabout lane. To improve the capacity of the roundabout system, proper values of the enter probability α and the out probability βcan be chosen.展开更多
A further understanding of the self-heating of coal was obtained by investigating the crossing point temperature(CPT) of different ranks of coal.The tests were carried out using a self-designed experimental system f...A further understanding of the self-heating of coal was obtained by investigating the crossing point temperature(CPT) of different ranks of coal.The tests were carried out using a self-designed experimental system for coal self-heating.50 g(±0.01 g) of coal particles ranging from 0.18 mm to 0.38 mm in size were put into a pure copper reaction vessel attached to the center of a temperature programmed enclosure.The temperature program increased the temperature at a rate of 0.8℃/min.Dry air was permitted to flow into the coal reaction vessel at different rates.The surrounding temperature and the coal temperature were monitored by a temperature logger.The results indicate that CPT is affected by coal rank,moisture,sulfur, and the experimental conditions.Higher ranked coals show higher CPT values.A high moisture content causes a delay phenomenon during the self-heating of the coal.Drying at 40℃decreases the effects of moisture.The reactivity of sulfur components in the coal is low under dry and low-temperature conditions. These components form a film that covers the coal surface and slightly inhibits the self-heating of the coal. The flow rate of dry air,and the heating rate of the surroundings,also affect the self-heating of the coal.The most appropriate experimental conditions for coal samples of a given weight and particle size were determined through contrastive analysis.Based on this analysis we propose that CPTs be determined under the same,or nearly the same conditions,for evaluation of the spontaneous combustion of coal.展开更多
A new reconfigumble planetary robots system (RPRS) is introduced. The locomotion mechanism alld crossing ditch ability by negotiation among ckild-robots are analyzed. Three configurations are introduced and their ch...A new reconfigumble planetary robots system (RPRS) is introduced. The locomotion mechanism alld crossing ditch ability by negotiation among ckild-robots are analyzed. Three configurations are introduced and their characteristics for crossing ditch compared. In order to cross the ditch whose width is broader than the length of the triangle wheel' s edge, a novel method based on the locomotion mechanism of the child-robot is proposed. This makes the two leading robots hold the first robot together with their velocities in opposite directions. Statics for the reconfigurable robot group are analyzed. The result shows that the motors can supply sufficient force moment to cross channel. Simulation .experiments are carried out with VC and OPENGL.展开更多
Cellular automata modeling techniques and the characteristics of mixed traffic flow were used to derive the 2-dimensional model presented here for simulation of pedestrian’s crossing dynamics. A conception of “stop...Cellular automata modeling techniques and the characteristics of mixed traffic flow were used to derive the 2-dimensional model presented here for simulation of pedestrian’s crossing dynamics. A conception of “stop point” is introduced to deal with traffic obstacles and resolve conflicts among pedestrians or between pedestrians and the other vehicles on the crosswalk. The model can be easily extended, is very efficient for simulation of pedestrian’s crossing dy- namics, can be integrated into traffic simulation software, and has been proved feasible by simulation experiments.展开更多
There is no spontaneous chromosome doubling in haploid plants produced by wheat X maize crossing. In order to obtain doubled haploid, two chromosome doubling methods were used. Results showed that: After adding colchi...There is no spontaneous chromosome doubling in haploid plants produced by wheat X maize crossing. In order to obtain doubled haploid, two chromosome doubling methods were used. Results showed that: After adding colchicine solution directly into a medium for young embryos that had been cultured 7 days, frequencies of embryo germination in colchicine concentrations of 50mg/L, 100mg/L and 200mg/L were 32.1% , 26.4% and 16.3% , respectively, and frequencies of chromosome doubling were 85.3% , 100% and 50.0% , respectively. But in the control without colchicine, the frequency of embryo germination was 67.4% and no seed was setting. As the time of colchicine treatment increased from 24 to 72 hours, the frequency of embryo germination was reduced, and 24 hours had better results. After soaking seeding crowns and roots with colchicine solution of 500mg/L, 750mg/L and 1 000mg/L for 5 hours, the frequencies of doubling were 89.6%, 76.0% and 73.3%, respectively. By soaking crowns and roots of strong seedings with 500mg/L colchicine solution, the frequency and efficiency of doubling were 98.2% and 93.2% , respectively.展开更多
Signalized intersections sometimes involve multistage pedestrian crossings, in which pedestrians cross to one or more islands and then wait there for a signal to continue. When signals are timed without attention to p...Signalized intersections sometimes involve multistage pedestrian crossings, in which pedestrians cross to one or more islands and then wait there for a signal to continue. When signals are timed without attention to pedestrian progression, pedestrian delay at multistage crossings can be very long. This paper addresses two issues. First, pedestrian delay at multistage crossings is rarely evaluated because there are no tools in the industry for that purpose except microsimulation. We present a numerical method for determining crossing delay with any number of stages and with the possibility of multiple WALK intervals per cycle. The same method can be applied to single stage crossings, to diagonal two-stage crossings where pedestrians may have path choice, and bicycle two-stage turns. This method has been implemented in a freely available online tool. Second, we describe several signal timing techniques for improving pedestrian and bicyclist progression, and thus reducing their delay, through multistage crossings. They include reservice for selected crossing phases, left turn overlaps, having pedestrian phases overlap each other, and bidirectional bicycle crossings which create path options for two-stage turns. Examples show the potential for large reductions in pedestrian delay, often with little or no increase in vehicular delay. In one example, the addition of a short pedestrian overlap phase reduced average pedestrian delay at a 3-stage crossing by 82 s while average vehicular delay increased by only 0.5 s.展开更多
Surface topographies such as micrometric edges and grooves have been widely used to improve neuron outgrowth.However,finding the mechanism of neuron–surface interactions on grooved substrates remains a challenge.In t...Surface topographies such as micrometric edges and grooves have been widely used to improve neuron outgrowth.However,finding the mechanism of neuron–surface interactions on grooved substrates remains a challenge.In this work,PC12 cells and chick forebrain neurons(CFNs)were cultured on grooved and smooth polyacrylonitrile substrates.It was found that CFNs showed a tendency of growing across groove ridges;while PC12 cells were only observed to grow in the longitudinal direction of grooves.To further investigate these observations,a 3D physical model of axonal outgrowth was developed.In this model,axon shafts are simulated as elastic 3D beams,accounting for the axon outgrowth as well as the focal contacts between axons and substrates.Moreover,the bending direction of axon tips during groove ridge crossing is governed by the energy minimization principle.Our physical model predicts that axonal groove ridge crossing is contributed by the bending compliance of axons,caused by lower Young’s modulus and smaller diameters.This work will aid the understanding of the mechanisms involved in axonal alignment and elongation of neurons guided by grooved substrates,and the obtained insights can be used to enhance the design of instructive scaffolds for nerve tissue engineering and regeneration applications.展开更多
Roads are conspicuous components in a river landscape;however,their impacts on river landscape patterns and ecological processes have not been systematically studied at the watershed scale.In this paper,the Lancang Ri...Roads are conspicuous components in a river landscape;however,their impacts on river landscape patterns and ecological processes have not been systematically studied at the watershed scale.In this paper,the Lancang River Valley in Yunnan Province,China was selected as a case to study road lateral disconnection and crossing impacts and identify river-road network interaction.This study was primarily focused on the road impacts on soil erosion intensity and patch density by using GIS analysis at different scales and explored their distribution with terrain factors.The results showed that river density revealed spatial autocorrelation although both of the roads and rivers were distributed unevenly in the valley.The lateral road(road curvature≥1.1)proportion correlated with soil erosion intensity(p 0.01)at the small sub-basin scale.Soil erosion intensity decreased with increasing lateral road buffer width.Light erosion generally accounted for a large proportion of the erosion in the lateral road buffer zones(1.0–4.0 km),while higher class lateral roads imposed greater impacts on soil erosion than lower class roads,which primarily had a moderate erosion level.In addition,the results of road-river intersection density indicated that road crossing impacts were significantly correlated with patch density at the small sub-basin scale.Topography factor(percent of slope>25°in each sub-basin had a close relationship with the ratio of total length of road line with curvature value≥1.1 to the total number of intersections.The correlation(p 0.01)between road impacts and terrain factor revealed that topography affected the road impact distribution in the Lancang River Valley.展开更多
Traditional "magic numbers" were once regarded as immutable throughout the nuclear chart. However, unexpected changes were found for unstable nuclei around N = 20. With both proton and neutron numbers around...Traditional "magic numbers" were once regarded as immutable throughout the nuclear chart. However, unexpected changes were found for unstable nuclei around N = 20. With both proton and neutron numbers around the magic number of 20, the neutron-rich ^(39)Cl isotope provides a good test case for the study of the quantumstate evolution across the major shell. In the present work, the negative parity states in ^(39)Cl are investigated through the β decay spectroscopy of 39 S. Newly observed γ transitions together with a new state are assigned into the level scheme of ^(39)Cl. The spin parity of 5/2^- for the lowest negative parity state in ^(39)Cl is reconfirmed using the combined γ transition information. These systematic observations of the negative parity states in ^(39)Cl allow a comprehensive comparison with the theoretical descriptions. The lowest 5/2^- state in ^(39)Cl remains exotic in terms of comparisons with existing theoretical calculations and with the neighboring isotopes having similar single-particle configurations. Further experimental and theoretical investigations are suggested.展开更多
The ratio of expectation crossings of dielectric elastomer balloon excited by random pressure is analytically evaluated in this letter. The Mooney-Rivlin model is adopted to describe the constitutive relation while th...The ratio of expectation crossings of dielectric elastomer balloon excited by random pressure is analytically evaluated in this letter. The Mooney-Rivlin model is adopted to describe the constitutive relation while the random pressure is described by Gaussian white noise. Through a specific transformation, the stochastic differential equations for the total energy and phase are derived. With the application of the stochastic averaging, the system total energy is then approximated by a one-dimensional diffusion pro-cess. Solving the associated Fokker-Planck-Kolmogorov (FPK) equation yields the stationary probability density of the system total energy. The ratio of expectation crossings is then derived based on the joint stationary probability density of stretch ratio and its ratio of change. The efficacy and accuracy of the proposed procedure are verified by comparing with the results from Monte Carlo simulation (MCS).展开更多
基金supported by the Construction and Scientific Research Project of the Zhejiang Provincial Department of Housing and Urban-Rural Development(No.2021K126,Granted byM.J.,Long,URL:https://jst.zj.gov.cn/)the ScientificResearch Project of ChinaConstruction 4th Engineering Bureau(No.CSCEC4B-2022-KTA-10,Granted by Z.C.,Bai,URL:https://4 bur.cscec.com/)+2 种基金the Scientific Research Project of China Construction 4th Engineering Bureau(No.CSCEC4B-2023-KTA-10,Granted by D.J.,Geng,URL:https://4bur.cscec.com/)the Natural Science Foundation of Hubei Province(No.2022CFD055,Granted by N.,Dai,URL:https://kjt.hubei.gov.cn/)the National Key Research and Development Program of China under Grant No.2022YFC3803002.
文摘According to the design specifications,the construction of extended piles involves traversing the tunnel’s upper region and extending to the underlying rock layer.To address this challenge,a subterranean transfer structure spanning multiple subway tunnels was proposed.Deliberating on the function of piles in the transfer structure as springs with axial and bending stiffness,and taking into account the force balance and deformation coordination conditions of beams and plates within the transfer structure,we established a simplified mechanical model that incorporates soil stratification by combining it with the Winkler elastic foundation beam model.The resolved established simplifiedmechanicalmodel employed finite difference technology and the Newton-Simpsonmethod,elucidating the mechanical mechanism of the transfer structure.The research findings suggest that the load carried by the upper structural columns can be transferred to the pile foundation beneath the beams through the transfer structure,subsequently reaching the deep soil layer and ensuring minimal impact on adjacent tunnels.The established simplified analysis method can be used for stress analysis of the transfer structure,concurrently considering soil stratification,pile foundation behavior,and plate action.The pile length,pile section size,and beam section size within the transfer structure should account for the characteristics of the upper load,ensuring an even distribution of the beam bending moment.
文摘This article is based on a recent model specifically defining magnetic field values around electrical wires. With this model, calculations of field around parallel wires were obtained. Now, this model is extended with the new concept of magnetic equipotential surface to magnetic field curves around crossing wires. Cases of single, double, and triple wires are described. Subsequent article will be conducted for more general scenarios where wires are neither infinite nor parallel.
文摘As a world-widely popular poem,Tennyson's Crossing the Bar attracts more and more people to cherish it.And this paper aims at translating it in a new way,and analyzing it in a fully scientific way.
文摘Unicellular gametophytes of Undaria pinnatifida (Harv.) Sur. were isolated in Qingdao, P. R. China in April 1993 and in Tokushima, southem Japan in March 1995. Diferent intraspecific crossings by using unicellular male and female gametophytes were successfully undertaken in Sept. of 1995 in Qingdao.Sporophytes were transplanted to two different locations for open an cultivation. One was at Zhanqiao (ZQ) Bay where the water current was slower than that of another location - Taipingjiao(TPJ). A total of218 adult sporophytes were harvested on January 12 and 18 from TPJ and ZQ repectively. For eacncombination, 10 sporophytes un cultivated. Analysis of the mprpholgical characteristics of adult spprophytes indicated that the longest length between two bases of the serration of pinnate bldes (W2) is a morphological characteristic that can be transferred from the parent plant to the next generations regardless of environmental variations. There was evidence that W2 was apparently determined by sex-linked factors, i.e, by male parental grametophyte.. Sporophytes from certain crossing combinations showed more vigorous growth than those from other crossing combinations. It is therrfore possible to select grametophyte strains which can be used as parental gametophytes for the seeding production of sporophytes with more vigorous growth within shorter cultivation period. The morphology of hybrids from a Qingdao strain and a Tokushima cultivated strain resembled that of both parental plants in frond feaures (wrinkled or smooth) and W2. Sporophyll formation also varied with strains. The fact that adult sporophytes resulting from the same crossing combinations have identical morphological characteristics under the same environmental conditions indicates the possibility of a new way to select strains which are expected to be ideal for commerical production by purposely selecting, propagating, and seeding unicellular gametophytes for sporeing production through freeliving techniques of gametophytes.
基金Project supported by the National Natural Science Foundation of China (Grant Nos 70371067, 10362001, 10347001 and 10562001), the National Natural Science Foundation of Guangxi Zhuang Autonomous Region, China (Grant No 04470307), and the Special Fund for the New Century Trained Talents Program of Guangxi Zhuang Autonomous Region, China (Grant No 20011204).
文摘The cellular automaton model is suggested to describe the traffic-flow at the grade roundabout crossing. After the simulation with computer, the fundamental properties of this model have been revealed. Analysing this kind of road structure, this paper transforms the grade roundabout crossing with inner-roundabout-lane and outer-roundabout-lane into a configuration with many bottlenecks. Because of the self-organization, the traffic flow remains unblocked under a certain vehicle density. Some results of the simulation are close to the actual design parameter.
基金Project supported by the National Natural Science Foundation of China (Grant No. 1097602/A06)
文摘In this paper,the energy spectrum of the two-photon Jaynes-Cummings model(TPJCM) is calculated exactly in the non-rotating wave approximation(non-RWA),and we study the level-crossing problem by means of fidelity.A narrow peak of the fidelity is observed at the level-crossing point,which does not appear at the avoided-crossing point.Therefore fidelity is perfectly suited for detecting the level-crossing point in the energy spectrum.
文摘We present an edge crossing minimization algorithm for hierarchical graphs based on genetic algorithms, and comparing it with some heuristic algorithms. The proposed algorithm is more efficient and has the following advantages: the frame of the algorithms is unified, the method is simple, and its implementation and revision are easy.
文摘Crossing Brookly Ferry is one of the most representative masterpieces composed by Walt Wiltman. In this pieces of writing, ones of the characteristics in this poem: optimism and unconventionality in its form are expressed in details.
文摘Objective:To compare laparoscopic Anderson-Hynes pyeloplasty(LAHP)and retroperitoneal laparoscopic YV-pyeloplasty(LRYVP)in ureteropelvic junction obstruction(UPJ)in presence of a crossing vessels(CV).Methods:Our database showed 380 UPJO-cases,who underwent laparoscopic retroperitoneal surgery during the last 2 decades including 206 non-dismembered LRYVP,157 dismembered pyeloplasties LAHP,and 17 cases of laparoscopic ureterolysis.Among them 198 cases were suitable for a matched-pair(2:1)analysis comparing laparoscopic retroperitoneal non-dismembered LRYVP(Group 1,n Z 131)and dismembered LAHP(Group 2,n Z 67)in presence of a crossing vessel.Patients were matched according to age,gender,kidney functions,and obstruction grade.Complications were graded according to modified Clavien-classification.Results:Comparative data were similar between both groups(LRYVP vs.LAHP)including mean operating time(112 min vs.114 min),complication rates(4.2%vs.7.3%)mainly Grade 1e2 according to Clavien classification,and success rates(90%vs.89%).These results reflected in the reviewed literature indicate that LRYVP provides the advantage of minimal dissection in case of CV with similar outcome.However,redundant pelvis and anteriorly crossing vessels still require a dismembered pyeloplasty LAHP.Conclusion:LRYVP has achieved similar results compared with the previous golden standard of open surgery,especially in case of crossing vessels apart from presence of a redundant pelvis or anteriorly crossing vessel.This can be further improved when using the small access retroperitoneoscopic technique respectively mini-laparoscopy.
文摘Fifteen capsicum combinations were made with 6 parents by (1/2)n(n-1) diallel crossing. Genetic parameters in the resistance to TMV, CMV, phytophthora blight, bacterial spot of these combinations were studied by Hayman. The results indicated that the resistance to TMV, CMV and bacterial spot conformed genetically to the “additive-dominant” model but the resistance to phytophthora blight did not and significant epistatic dominance effect existed in it. F1 hybrid's resistance to CMV was controlled by homozygous dominant gene (s), but resistance to bacterial spot by heterozygous one (s). There were little, or no sum of dominant effect and genomes controlling the dominant expression of F1 hybrids in its phytophthora blight resistance.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 10562001,10762005 and 10962002)
文摘This paper presents a cellular automaton traffic flow model with an open boundary condition to describe the traffic flow at a roundabout crossing with an inner roundabout lane and an outer roundabout lane. The simulation results show that the boundary condition, bottlenecks and the self-organization affect the traffic flow at the roundabout crossing. Because of the effect of bottlenecks, jams easily appear on the inner roundabout lane. To improve the capacity of the roundabout system, proper values of the enter probability α and the out probability βcan be chosen.
基金financial supports provided by the National Natural Science Foundation of China(Nos. 50927403 and 50674088)the Natural Science Foundation of Jiangsu Province(No.BK2009004)the Research Foundation of State Key Laboratory of Coal Resources and Safe Mining(No. SKLCRSM08X06)
文摘A further understanding of the self-heating of coal was obtained by investigating the crossing point temperature(CPT) of different ranks of coal.The tests were carried out using a self-designed experimental system for coal self-heating.50 g(±0.01 g) of coal particles ranging from 0.18 mm to 0.38 mm in size were put into a pure copper reaction vessel attached to the center of a temperature programmed enclosure.The temperature program increased the temperature at a rate of 0.8℃/min.Dry air was permitted to flow into the coal reaction vessel at different rates.The surrounding temperature and the coal temperature were monitored by a temperature logger.The results indicate that CPT is affected by coal rank,moisture,sulfur, and the experimental conditions.Higher ranked coals show higher CPT values.A high moisture content causes a delay phenomenon during the self-heating of the coal.Drying at 40℃decreases the effects of moisture.The reactivity of sulfur components in the coal is low under dry and low-temperature conditions. These components form a film that covers the coal surface and slightly inhibits the self-heating of the coal. The flow rate of dry air,and the heating rate of the surroundings,also affect the self-heating of the coal.The most appropriate experimental conditions for coal samples of a given weight and particle size were determined through contrastive analysis.Based on this analysis we propose that CPTs be determined under the same,or nearly the same conditions,for evaluation of the spontaneous combustion of coal.
基金Project supported by National High-Technology Research and De-velopment Program(Grant No .863 -2002 -AA422130)
文摘A new reconfigumble planetary robots system (RPRS) is introduced. The locomotion mechanism alld crossing ditch ability by negotiation among ckild-robots are analyzed. Three configurations are introduced and their characteristics for crossing ditch compared. In order to cross the ditch whose width is broader than the length of the triangle wheel' s edge, a novel method based on the locomotion mechanism of the child-robot is proposed. This makes the two leading robots hold the first robot together with their velocities in opposite directions. Statics for the reconfigurable robot group are analyzed. The result shows that the motors can supply sufficient force moment to cross channel. Simulation .experiments are carried out with VC and OPENGL.
文摘Cellular automata modeling techniques and the characteristics of mixed traffic flow were used to derive the 2-dimensional model presented here for simulation of pedestrian’s crossing dynamics. A conception of “stop point” is introduced to deal with traffic obstacles and resolve conflicts among pedestrians or between pedestrians and the other vehicles on the crosswalk. The model can be easily extended, is very efficient for simulation of pedestrian’s crossing dy- namics, can be integrated into traffic simulation software, and has been proved feasible by simulation experiments.
基金supported by the Beijing Nature Science Foundation(5982011).
文摘There is no spontaneous chromosome doubling in haploid plants produced by wheat X maize crossing. In order to obtain doubled haploid, two chromosome doubling methods were used. Results showed that: After adding colchicine solution directly into a medium for young embryos that had been cultured 7 days, frequencies of embryo germination in colchicine concentrations of 50mg/L, 100mg/L and 200mg/L were 32.1% , 26.4% and 16.3% , respectively, and frequencies of chromosome doubling were 85.3% , 100% and 50.0% , respectively. But in the control without colchicine, the frequency of embryo germination was 67.4% and no seed was setting. As the time of colchicine treatment increased from 24 to 72 hours, the frequency of embryo germination was reduced, and 24 hours had better results. After soaking seeding crowns and roots with colchicine solution of 500mg/L, 750mg/L and 1 000mg/L for 5 hours, the frequencies of doubling were 89.6%, 76.0% and 73.3%, respectively. By soaking crowns and roots of strong seedings with 500mg/L colchicine solution, the frequency and efficiency of doubling were 98.2% and 93.2% , respectively.
文摘Signalized intersections sometimes involve multistage pedestrian crossings, in which pedestrians cross to one or more islands and then wait there for a signal to continue. When signals are timed without attention to pedestrian progression, pedestrian delay at multistage crossings can be very long. This paper addresses two issues. First, pedestrian delay at multistage crossings is rarely evaluated because there are no tools in the industry for that purpose except microsimulation. We present a numerical method for determining crossing delay with any number of stages and with the possibility of multiple WALK intervals per cycle. The same method can be applied to single stage crossings, to diagonal two-stage crossings where pedestrians may have path choice, and bicycle two-stage turns. This method has been implemented in a freely available online tool. Second, we describe several signal timing techniques for improving pedestrian and bicyclist progression, and thus reducing their delay, through multistage crossings. They include reservice for selected crossing phases, left turn overlaps, having pedestrian phases overlap each other, and bidirectional bicycle crossings which create path options for two-stage turns. Examples show the potential for large reductions in pedestrian delay, often with little or no increase in vehicular delay. In one example, the addition of a short pedestrian overlap phase reduced average pedestrian delay at a 3-stage crossing by 82 s while average vehicular delay increased by only 0.5 s.
基金This study was partially supported by the National Key Research and Development Program of China(Grant No.2018YFA0703000)the Key Research and Development Program of Zhejiang Province(Grant No.2017C01063)+2 种基金the Science Fund for Creative Research Groups of the National Natural Science Foundation of China(Grant No.51821093)the National Natural Science Foundation of China(Grant Nos.U1609207,11672268)ZJU Scholarship for Outstanding Doctoral Candidates and Scholarship Program supported by China Scholarship Council(No.201906320187).
文摘Surface topographies such as micrometric edges and grooves have been widely used to improve neuron outgrowth.However,finding the mechanism of neuron–surface interactions on grooved substrates remains a challenge.In this work,PC12 cells and chick forebrain neurons(CFNs)were cultured on grooved and smooth polyacrylonitrile substrates.It was found that CFNs showed a tendency of growing across groove ridges;while PC12 cells were only observed to grow in the longitudinal direction of grooves.To further investigate these observations,a 3D physical model of axonal outgrowth was developed.In this model,axon shafts are simulated as elastic 3D beams,accounting for the axon outgrowth as well as the focal contacts between axons and substrates.Moreover,the bending direction of axon tips during groove ridge crossing is governed by the energy minimization principle.Our physical model predicts that axonal groove ridge crossing is contributed by the bending compliance of axons,caused by lower Young’s modulus and smaller diameters.This work will aid the understanding of the mechanisms involved in axonal alignment and elongation of neurons guided by grooved substrates,and the obtained insights can be used to enhance the design of instructive scaffolds for nerve tissue engineering and regeneration applications.
基金Under the auspices of Nonprofit Environment Protection Specific Project of China(No.201209029-4)National Natural Science Foundation of China(No.50939001)
文摘Roads are conspicuous components in a river landscape;however,their impacts on river landscape patterns and ecological processes have not been systematically studied at the watershed scale.In this paper,the Lancang River Valley in Yunnan Province,China was selected as a case to study road lateral disconnection and crossing impacts and identify river-road network interaction.This study was primarily focused on the road impacts on soil erosion intensity and patch density by using GIS analysis at different scales and explored their distribution with terrain factors.The results showed that river density revealed spatial autocorrelation although both of the roads and rivers were distributed unevenly in the valley.The lateral road(road curvature≥1.1)proportion correlated with soil erosion intensity(p 0.01)at the small sub-basin scale.Soil erosion intensity decreased with increasing lateral road buffer width.Light erosion generally accounted for a large proportion of the erosion in the lateral road buffer zones(1.0–4.0 km),while higher class lateral roads imposed greater impacts on soil erosion than lower class roads,which primarily had a moderate erosion level.In addition,the results of road-river intersection density indicated that road crossing impacts were significantly correlated with patch density at the small sub-basin scale.Topography factor(percent of slope>25°in each sub-basin had a close relationship with the ratio of total length of road line with curvature value≥1.1 to the total number of intersections.The correlation(p 0.01)between road impacts and terrain factor revealed that topography affected the road impact distribution in the Lancang River Valley.
基金Supported by JSPS and CNRS under the Japan-France Research Cooperative Programthe Grant-in-Aid for Scientific Research on Innovative Areas"Toward new frontiers:Encounter and synergy of state-of-the-art astronomical detectors and exotic quantum beams",JSPS/MEXT KAKENHI under Grant Nos JP18HO3692 and JP18H05462+1 种基金the National Key R&D Program of China(2018YFA0404403)the National Natural Science Foundation of China Nos 11775316,11535004,11875074 and 11875073
文摘Traditional "magic numbers" were once regarded as immutable throughout the nuclear chart. However, unexpected changes were found for unstable nuclei around N = 20. With both proton and neutron numbers around the magic number of 20, the neutron-rich ^(39)Cl isotope provides a good test case for the study of the quantumstate evolution across the major shell. In the present work, the negative parity states in ^(39)Cl are investigated through the β decay spectroscopy of 39 S. Newly observed γ transitions together with a new state are assigned into the level scheme of ^(39)Cl. The spin parity of 5/2^- for the lowest negative parity state in ^(39)Cl is reconfirmed using the combined γ transition information. These systematic observations of the negative parity states in ^(39)Cl allow a comprehensive comparison with the theoretical descriptions. The lowest 5/2^- state in ^(39)Cl remains exotic in terms of comparisons with existing theoretical calculations and with the neighboring isotopes having similar single-particle configurations. Further experimental and theoretical investigations are suggested.
基金supported by the National Natural Science Foundation of China(11672262,11472240,11532011,and 11621062)
文摘The ratio of expectation crossings of dielectric elastomer balloon excited by random pressure is analytically evaluated in this letter. The Mooney-Rivlin model is adopted to describe the constitutive relation while the random pressure is described by Gaussian white noise. Through a specific transformation, the stochastic differential equations for the total energy and phase are derived. With the application of the stochastic averaging, the system total energy is then approximated by a one-dimensional diffusion pro-cess. Solving the associated Fokker-Planck-Kolmogorov (FPK) equation yields the stationary probability density of the system total energy. The ratio of expectation crossings is then derived based on the joint stationary probability density of stretch ratio and its ratio of change. The efficacy and accuracy of the proposed procedure are verified by comparing with the results from Monte Carlo simulation (MCS).