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Effect of Heatpipe Array Condenser Section Length on Thermal Cooling of Li-Ion Batteries
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作者 Olanrewaju M.Oyewola Olawale S.Ismail Adetokunbo A.Awonusi 《Frontiers in Heat and Mass Transfer》 EI 2024年第2期475-490,共16页
One of the new methods for ensuring that the battery in a thermal energy storage system is kept at the proper temperature is the heat pipe-based ThermalManagement System(TMS).In this study,the improvement of cooling p... One of the new methods for ensuring that the battery in a thermal energy storage system is kept at the proper temperature is the heat pipe-based ThermalManagement System(TMS).In this study,the improvement of cooling performance of a heat pipe based TMS is examined through the variation of condenser section length of heat pipes in an array.The TMSs with an array of heat pipes with different condenser section lengths are considered.The system performances are evaluated using a validated numerical method.The results show that a heat pipebased TMS provides the best cooling performance when a wavy-like variation is employed and when the condenser section length of the last set of the heat pipe in the array is greater than that of the penultimate set.The maximum cell temperature and the maximum temperature difference within the cell of this TMS are decreased by 4.2 K and 1.1 K,respectively,when compared to the typical heat pipe based TMS with zero variation in its condenser section length.Conclusively,the strategy offers an improvement in the thermal uniformity for all the TMS cases. 展开更多
关键词 thermal cooling condenser section length Li-ion battery heatpipe
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On Sentence Complexity in THE TIMES: A Comparative Study of SentenceLength and Sentence Complexity in the News Section and the Sports Section
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作者 赤列德吉 《海外英语》 2014年第15期3-4,共2页
My investigation will serve two purposes. First, I shall investigate the function of the subclauses in the corpus in relation to their complexity, and I shall establish whether there is a correlation between sentence ... My investigation will serve two purposes. First, I shall investigate the function of the subclauses in the corpus in relation to their complexity, and I shall establish whether there is a correlation between sentence length and sentence complexity.Second, I shall analyse the complexity of the subclauses collected from the two sections and compare the results from these sections, focusing on finite subclauses and non-finite subclauses. I hope to be able to point out some differences in style between the news and sports sections concerning the use of subordinate clauses in various syntactic functions in order to examine how the choice of linguistic structures differs in different sections of The Times. 展开更多
关键词 SENTENCE length SENTENCE COMPLEXITY style MARKER t
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The Effective Buckling Length on Numerical Study of Pipe-Sectioned Pier-Pile Integral Steel Structure
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作者 Takayuki Omori Akira Kasai Rei Kohara 《Open Journal of Earthquake Research》 2017年第4期159-167,共9页
Pier-Pile integral structures provide construction works with many environmental and landscape advantages. For example, the space required to construct these structures is smaller than that of other bridges due to the... Pier-Pile integral structures provide construction works with many environmental and landscape advantages. For example, the space required to construct these structures is smaller than that of other bridges due to the footing being removed, meaning that it is not necessity to greatly change the surroundings of these bridges. While there are environmental and landscape advantages, there are also a few demerits for the overall land-scape designs, including demerits in the design of this proposed structure which consists of relatively slender parts. This proposed structure has already been constructed in areas where possibility of a severe earthquake is low. However, some problems that have yet to be examined are related to the use of this proposed structure in areas where earthquakes are frequent. Lacking detailed studies of its behavior during severe earthquakes, it is currently difficult to construct these structures in Japan. Consequently, it is necessary to investigate in detail limited performance about compression and bending moment, and earthquake- resistant performance of these structures in order to resolve these problems. In this paper, It was clarified the relationship between the rigidity of the ground and the effective buckling length by buckling analysis and elasto- plastic finite deformation analysis. Moreover, it was proposed a simplified formula using a proposed characteristic value β and several factors for analysis accuracy. A simplified formula would support to determine the effective buckling length to design the pier using the load-bearing capacity curve based on the slenderness ratio parameter. 展开更多
关键词 Pire-Pile INTEGRAL Steel Structures EFFECTIVE BUCKLING length PIPE section
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Influence of anchorage length and pretension on the working resistance of rock bolt based on its tensile characteristics 被引量:3
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作者 Jucai Chang Kai He +3 位作者 Dongdong Pang Dong Li Chuanming Li Bingjun Sun 《International Journal of Coal Science & Technology》 EI CAS CSCD 2021年第6期1384-1399,共16页
In coal mining roadway support design,the working resistance of the rock bolt is the key factor affecting its maximum support load.Effective improvement of the working resistance is of great significance to roadway su... In coal mining roadway support design,the working resistance of the rock bolt is the key factor affecting its maximum support load.Effective improvement of the working resistance is of great significance to roadway support.Based on the rock bolt’s tensile characteristics and the mining roadway surrounding rock deformation,a mechanical model for calculating the working resistance of the rock bolt was established and solved.Taking the mining roadway of the 17102(3)working face at the Panji No.3 Coal Mine of China as a research site,with a quadrilateral section roadway,the influence of pretension and anchorage length on the working resistance of high-strength and ordinary rock bolts in the middle and corner of the roadway is studied.The results show that when the bolt is in the elastic stage,increasing the pretension and anchorage length can effectively improve the working resistance.When the bolt is in the yield and strain-strengthening stages,increasing the pretension and anchorage length cannot effectively improve the working resistance.The influence of pretension and anchorage length on the ordinary and high-strength bolts is similar.The ordinary bolt’s working resistance is approximately 25 kN less than that of the high-strength bolt.When pretension and anchorage length are considered separately,the best pretensions of the high-strength bolt in the middle of the roadway side and the roadway corner are 41.55 and 104.26 kN,respectively,and the best anchorage lengths are 1.54 and 2.12 m,respectively.The best anchorage length of the ordinary bolt is the same as that of the high-strength bolt,and the best pretension for the ordinary bolt in the middle of the roadway side and at the roadway corner is 33.51 and 85.12 kN,respectively.The research results can provide a theoretical basis for supporting the design of quadrilateral mining roadways. 展开更多
关键词 Working resistance of rock bolt PRETENSION Anchorage length Ordinary bolt High-strength bolt Quadrilateral section roadway
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Analysis of the mass of behind-armor debris generated by RHA subjected to normal penetration of variable cross-section EFP 被引量:4
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作者 Boyang Xing Dongjiang Zhang +7 位作者 Zhenyan Guo Yunhui Hou Rui Guo Rongzhong Liu Liang Chen Hao Zhou Yongliang Yang Jianhua Luo 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2019年第3期390-397,共8页
Analyzing the mass of behind-armor debris (BAD) generated by Rolled Homogeneous Armor (RHA) subjected to normal penetration of variable cross-section Explosively Formed Projectile (EFP) is the purpose of this paper. S... Analyzing the mass of behind-armor debris (BAD) generated by Rolled Homogeneous Armor (RHA) subjected to normal penetration of variable cross-section Explosively Formed Projectile (EFP) is the purpose of this paper. So theoretical analysis, numerical simulation and experimental data are combined to analyze the influence of variable cross-section characteristic on the time history of crater radius. Moreover the relationships between time history of crater radius (as well as mass of BAD) and the thickness of RHA (from 30mm to 70 mm) and the impact velocity of EFP (1650 m/s to 1860 m/s) are also investigated. The results indicate that: 1) being compared to the variable cross-section characteristic is ignored, the theoretical time history of crater radius is in better agreement with the simulation results when the variable cross-section characteristic is considered;2) being compared to the other three conditions of plug, the theoretical mass of BAD is in the best agreement with the simulation results when the shape of plug is frustum of a cone and the angle between generatrix and bottom is 45- and the axial length of mushroom is considered. 展开更多
关键词 Explosively formed PROJECTILE Behind-armor DEBRIS Variable CROSS-section characteristic Shape of plug Axial length of MUSHROOM theoretical model
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Determination of Telomere Length by the Quantitative Fluorescence <i>in Situ</i>Hybridization (Q-FISH) Method
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作者 Junko Aida Naotaka Izumiyama-Shimomura +6 位作者 Ken-ichi Nakamura Naoshi Ishikawa Masanori Terai Yoko Matsuda Shinsuke Aida Tomio Arai Kaiyo Takubo 《American Journal of Analytical Chemistry》 2014年第12期775-783,共9页
Telomeres are nucleoprotein complexes located at the ends of eukaryotic chromosomes and are shorten with aging or various causes. Shortened telomere plays an important role for chromosomal instability in carcinogenesi... Telomeres are nucleoprotein complexes located at the ends of eukaryotic chromosomes and are shorten with aging or various causes. Shortened telomere plays an important role for chromosomal instability in carcinogenesis, or a number of diseases in relation to aging. FISH using peptide-nucleic acid (PNA) probe is suitable for analyzing telomeres, because telomere is a part of DNA molecule and localized in chromosomal end in loop shape structure (T-loop). We introduce our telomere analysis for tissue sections and cultured cells in this paper. On the tissue sections, we analyze telomere length with telomere intensity to centromere intensity ratio (TCR), centromere as an inner control. In the cultured cells, we analyze telomere lengths on each chromosome with karyotyping. Those Q-FISH methods by PNA probe are an accurate and reliable tool for research on telomere lengths in various conditions in biology. 展开更多
关键词 TELOMERE TELOMERE length Q-FISH Tissue section CHROMOSOME
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Accurate calculation of the elastic scattering properties of ^7Li atoms at ultralow temperatures 被引量:2
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作者 孙金锋 张计才 王杰敏 《Chinese Physics B》 SCIE EI CAS CSCD 2006年第3期531-535,共5页
The elastic scattering properties for collisions between two ^7Li atoms are investigated in the cold and ultracold regimes separately. Based on recent theoretical and experimental results, we present the improved hybr... The elastic scattering properties for collisions between two ^7Li atoms are investigated in the cold and ultracold regimes separately. Based on recent theoretical and experimental results, we present the improved hybrid potentials for the singlet X^1 ∑g^+ and triplet a^3 ∑u^+ ground states of the Li2, Our calculated values for the scattering lengths α and the effective ranges re are compared with previous ones, and found them to be in good agreement. The scattering lengths are 34.6α0 for the singlet state and -27.6α0 for the triplet state. Shape resonances occur in the collisions at low energies. We also calculate the total cross sections and the energy positions of shape resonances for both X^1 ∑g^+ and a^3 ∑u^+ states. 展开更多
关键词 scattering length elastic cross section shape resonance
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On stability of elastic domain during isothermal solid-solid phase transformationin a tube configuration 被引量:1
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作者 Liang Dong Qing-Ping Sun 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2012年第3期683-694,共12页
Under isothermal quasi-static stretching the phase transition of a superelastic NiTi tube involves the formation (during loading) and vanishing (in unloading) of a high strain (martensite) domain. The two events... Under isothermal quasi-static stretching the phase transition of a superelastic NiTi tube involves the formation (during loading) and vanishing (in unloading) of a high strain (martensite) domain. The two events are accompanied by a rapid stress drop/rise due to the formation/vanishing of do- main fronts. From a thermodynamic point of view, both are instability phenomena that occur once the system reaches its critical state. This paper investigates the stability of a shrink- ing cylindrical domain in a tube configuration during unload- ing. The energetics and thermodynamic driving force of the cylindrical domain are quantified by using an elastic inclu- sion model. It is demonstrated that the two domain fronts ex- hibit strong interaction when they come close to each other, which brings a peak in the total energy and a sign change in the thermodynamic driving force. It is proved that such domain front interaction plays an important role in control- ling the stability of the domain and in the occurrence of stress jumps during domain vanishing. It is also shown that the pro- cess is governed by two nondimensional length scales (the normalized tube length and normalized wall-thickness) and that the length scale dependence of the critical domain length and stress jump for the domain vanishing can be quantified by the elastic inclusion model. 展开更多
关键词 cylindrical elastic domain Stability of domain Domain front Critical domain length Stress jump ~ ther-modynamic driving force
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Calculation of the elastic scattering properties for cold and ultracold 39K atoms in a triplet state
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作者 胡秋波 王晓飞 +1 位作者 孙金锋 朱遵略 《Chinese Physics B》 SCIE EI CAS CSCD 2007年第8期2367-2370,共4页
The elastic scattering properties for collisions between cold and ultracold 39K atoms in a triplet state are investigated. Based on the recent theoretical and experimental results, the improved hybrid potential is pre... The elastic scattering properties for collisions between cold and ultracold 39K atoms in a triplet state are investigated. Based on the recent theoretical and experimental results, the improved hybrid potential is presented for a triplet α3∑u^+ ground state of K2. Our calculated value of the s-wave scattering length a by using the Numerov method for the triplet state is 79.578α0 and found to be in good agreement with the previous ones. The numbers of bound states are supported by the molecular potential. Pronounced shape resonances appear for the l = 3 partial waves for the α3∑u^+ state. Furthermore, the s-wave scattering cross section, the total cross section and energy positions of shape resonances for the α3∑u^+ state are calculated. 展开更多
关键词 scattering length effective range elastic cross section shape resonance
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Calculation of the elastic collision properties of Na and Li atoms at ultracold temperature
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作者 张计才 张莹 +1 位作者 杜丙阁 孙金锋 《Chinese Physics B》 SCIE EI CAS CSCD 2009年第4期1486-1490,共5页
This paper firstly reports a theoretical study of elastic scattering properties in a mixture of 23Na and 7Li atoms at cold and ultracold temperatures in detail. Based on the new constructed accurate singlet X1∑g+ an... This paper firstly reports a theoretical study of elastic scattering properties in a mixture of 23Na and 7Li atoms at cold and ultracold temperatures in detail. Based on the new constructed accurate singlet X1∑g+ and the triplet a3∑u+ states interatomic potentials for 23Na7Li mixture, it calculates the scattering lengths and the effective ranges by three computational methods, and obtains good agreements. Using the mass scaling method, it also calculates 23Na6Li scattering lengths and s-wave and total elastic cross sections, whose rich resonance structures were found and interpreted in terms of quasibound diatomic levels trapped behind a centrifugal barrier. 展开更多
关键词 scattering length elastic cross section variable phase method
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CONCEPTUAL DEVELOPMENT OF THE EARTH TUBE COOLING SYSTEM FOR A TALL BUILDING
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作者 Xiangfeng Liu Miao Xu +1 位作者 Juanli Guo Renjie Zhu 《Journal of Green Building》 2019年第2期3-28,共26页
Earth tubes are earth-to-air heat exchangers that are frequently utilized in energy conscious low-rise buildings, but are scarcely reported for tall buildings. The feasibility of applying earth tube cooling to tall bu... Earth tubes are earth-to-air heat exchangers that are frequently utilized in energy conscious low-rise buildings, but are scarcely reported for tall buildings. The feasibility of applying earth tube cooling to tall buildings in a hot summer and cold winter climate zone was studied in this paper. Firstly, the designed cooling load of a tall building was obtained from the energy simulation using the baseline and the modified models with applicable energy efficiency measures. Based on the load, the required cooling capacity, the overall section area and the effective length of the earth tube system was deduced from the heat transfer and fluid flow calculation analytically. Then the performance of the earth tube system was crosschecked and verified via the Computational Fluid Dynamics (CFD) simulation. In the CFD simulation, earth tubes with different diameters and lengths, as well as a full-scale earth tube model with surrounding soil above the depth of constant temperature, were investigated. The outlet air temperatures of the full-scale models were computed with the consideration of different axial distances between adjacent tubes. Meanwhile, multiple conceptual design schemes and the tunnel construction method for the earth tube system were proposed from the perspective of performance enhancement, constructability, efficiency and economy. It revealed that earth tube systems are conditionally feasible for some tall buildings if their design guidelines for climate, underground spaces, construction method, friction of tube interior surface, optimization of effective length and axial distance, as well as synergy with other energy efficiency measures are followed. Even the cooling capacity of earth tubes degrade with time due to the accumulated heat underground, but in a hot summer and cold winter climate zone it can still possibly produce cooled air for a tall building with a Floor Area Ratio of less than 7 effectively in summer. 展开更多
关键词 earth tube energy efficiency tall building cooling capacity overall section area effective length
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Dynamic behavior of single-layer latticed cylindrical shells subjected to seismic loading 被引量:4
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作者 沈世钊 邢佶慧 范峰 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2003年第2期269-279,共11页
The single-layer latticed cylindrical shell is one of the most widely adopted space-fl'amed structures.In this paper,free vibration properties and dynamic response to horizontal and vertical seismic waves of singl... The single-layer latticed cylindrical shell is one of the most widely adopted space-fl'amed structures.In this paper,free vibration properties and dynamic response to horizontal and vertical seismic waves of single-layer latticed cylindrical shells are analyzed by the finite element method using ANSYS software.In the numerical study,where hundreds of cases were analyzed,the parameters considered included rise-span ratio,length-span ratio,surface load and member section size.Moreover,to better define the actual behavior of single-layer latticed shells,the study is focused on the dynamic stress response to both axial forces and bending moments.Based on the numerical results,the effects of the parameters considered on the stresses are discussed and a modified seismic force coefficient method is suggested.In addition,some advice based on these research results is presented to help in the future design of such structures. 展开更多
关键词 single-layer latticed cylindrical shell dynamic behaviors seismic force coefficient method rise-span ratio length-span ratio surface load intensity member section size
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Size-dependent surface tension of a cylindrical nanobubble in liquid Ar 被引量:1
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作者 闫红 朱如曾 魏久安 《Chinese Physics B》 SCIE EI CAS CSCD 2012年第8期146-151,共6页
In view of the continued disputes on the fundamental question of whether the surface tension of a vapour bubble in liquid argon increases, or decreases, or remains unchanged with the increase of curvature radius, a cy... In view of the continued disputes on the fundamental question of whether the surface tension of a vapour bubble in liquid argon increases, or decreases, or remains unchanged with the increase of curvature radius, a cylindrical vapour bubble of argon is studied by molecular dynamics simulation in this paper instead of spherical vapour bubble so as to reduce the statistical error. So far, the surface tension of the cylindrical vapour bubble has not been studied by molecular dynamics simulation in the literature. Our results show that the surface tension decreases with radius increasing. By fitting the Tolman equation with our data, the Tolman length σ = -0.6225 sigma is given under cut-off radius 2.5σ, where σ = 0.3405 nm is the diameter of an argon atom. The Tolman length of Ar being negative is affirmed and the Tolman length of Ar being approximately zero given in the literature is negated, and it is pointed out that this error is attributed to the application of the inapplicable empirical equation of state and the neglect of the difference between surface tension and an equimolar surface. 展开更多
关键词 cylindrical nanobubble surface tension Tolman length molecular dynamics simulation
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Optical Path Length,Temperature,and Wavelength Effects Simulation on Ozone Gas Absorption Cross Sections towards Green Communications
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作者 Michael David mohd haniff ibrahim +3 位作者 Sevia Mahdaliza Idrus Nor Hafizah Ngajikin Asrul Izam Azmi Tay Ching En Marcus 《Journal of Electronic Science and Technology》 CAS CSCD 2016年第3期199-204,共6页
Ozone is a green house gas. Ozone absorption cross sections have been reported with discrepancies and inconsistencies. In this paper, simultaneous effects of the optical path length and temperature variations on ozone... Ozone is a green house gas. Ozone absorption cross sections have been reported with discrepancies and inconsistencies. In this paper, simultaneous effects of the optical path length and temperature variations on ozone gas absorption cross sections are investigated at different wavelengths. HITRAN 2012, the latest available line list on spectralcalc.com simulator, is used in this study to simulate ozone gas absorption cross sections in relation to the simultaneous effects of the optical path length and temperature at the wavelengths of 603 nm and 575 nm. Results obtained for gas cells with the optical path length from 10 cm to 120 cm show that the decrease in temperatures from 313 K to 103 K results in the increase in ozone gas absorption cross sections. At wavelengths of 603 nm and 575 nm, the percentage increase of ozone gas absorption cross sections is 1.22% and 0.71%, respectively. Results obtained in this study show that in the visible spectrum, at constant pressure, ozone gas absorption cross sections are dependent on the temperature and wavelength but do not depend on the optical path length. Analysis in this work addresses discrepancies in ozone gas absorption cross sections in relation to the temperature in the visible spectrum; thus, the results can be applied to get optimal configuration of high accuracy ozone gas sensors. 展开更多
关键词 Index Terms--Absorption cross sections length OZONE PRESSURE TRANSMITTANCE visible spectrum.
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Steric Effects in the Cl+CHD3(v1=1) Reaction
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作者 Fengyan Wang Kopin Liu 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2013年第6期705-709,I0004,共6页
A recent study has revealed a full 3-dimentional reactive scattering picture of the reaction CI+CHD3(v1=1) as the C1 atoms attack CHD3 from various directions respective to the C-H stretching bond. The reported pol... A recent study has revealed a full 3-dimentional reactive scattering picture of the reaction CI+CHD3(v1=1) as the C1 atoms attack CHD3 from various directions respective to the C-H stretching bond. The reported polarization-dependent differential cross sections provide the most detailed characterization of the influences of reagent alignments on reactivity. To convey the stereo-specific information more accessible to general chemists, we show here, by proper symmetry considerations, how to retrieve from the measurements the relative integral and differential cross sections of two most common collision geometries: the end-on versus side-on attacks. The results, albeit coarse-grained, provide an appealing picture that not only reinforces our intuition about chemical reactivity, but also sheds more light on the conventional (unpolarized) attributes. 展开更多
关键词 Steric effect Integrate cross section cylindrical symmetry Slice image Crossed beam technique
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Post-Buckling Behavior of Laminated Composite Cylindrical Shells Subjected to Axial, Bending and Torsion Loads 被引量:1
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作者 Yengula Venkata Narayana Jagadish Babu Gunda +1 位作者 Ravinder Reddy Pinninti Markandeya Ravvala 《World Journal of Engineering and Technology》 2015年第4期185-194,共10页
In present work, post-buckling behavior of imperfect (of eigen form) laminated composite cylindrical shells with different L/D and R/t ratios subjected to axial, bending and torsion loads has been investigated by usin... In present work, post-buckling behavior of imperfect (of eigen form) laminated composite cylindrical shells with different L/D and R/t ratios subjected to axial, bending and torsion loads has been investigated by using an equilibrium path approach in the finite element analysis. The Newton-Raphson approach as well as the arc-length approach is used to ensure the correctness of the equilibrium paths up to the limit point load. Post-buckling behavior of imperfect cylindrical shells with different L/D and R/t ratios of interest is obtained and the theoretical knock-down factors are reported for the considered cylindrical shells. 展开更多
关键词 POST-BUCKLING cylindrical Shells Eigen IMPERFECTION Shapes AXIAL Compressive LOAD BENDING LOAD Torsion LOAD Arc-length Method KNOCK-DOWN Factor
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Time Course of Postoperative Complications in Low-Risk Women after Planned Cesarean Section
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作者 Anne Raabjerg Kruse Linn Håkonsen Arendt +5 位作者 Christian Erikstrup Ulrik Schiøler Kesmodel Finn Friis Lauszus Niels Uldbjerg Iben Sundtoft Axel Forman 《Open Journal of Obstetrics and Gynecology》 2022年第5期394-407,共14页
Objectives: Length of hospital stay after cesarean section is today much shorter than previously, and a stay of only 1 day is used in many departments. However, complications requiring immediate treatment must be diag... Objectives: Length of hospital stay after cesarean section is today much shorter than previously, and a stay of only 1 day is used in many departments. However, complications requiring immediate treatment must be diagnosed before leaving hospital. We assessed the time interval from planned cesarean section to diagnosis of major complications in low-risk women to estimate a safe time of discharge. Methods: We performed a retrospective observational study among 5633 women undergoing planned cesarean section from 2001-2017 at Aarhus University Hospital, Denmark. The inclusion criterion was postoperative complication graded as Clavien-Dindo ≥ II. Exclusion criteria were preoperative comorbidity or problems during surgery indicative of need for prolonged stay. Time from cesarean section to suspicion of a postoperative complication was the primary endpoint. Results: The study population consisted of 116 women with unexpected postoperative complications, 47 classified as Clavien-Dindo II and 69 as Clavien-Dindo III-IV. In 63 of the 116, the diagnoses were suspected within 24 hours (Clavien-Dindo II: 25, Clavien-Dindo III-IV: 38). These included all cases of relaparotomy and uterine atony with immediate need of medical treatment. Acute colonic pseudo-obstruction was diagnosed within 2 days, while other complications were suspected and treated 2 to 10 days postoperatively. Conclusions: Among low-risk women with a postoperative complication, all cases requiring relaparotomy and medically treated uterine atony were suspected within 24 hours after surgery. Discharge 24 hours after planned cesarean section seems safe in low-risk patients. 展开更多
关键词 Cesarean section Postoperative Complications Postoperative Hemorrhage Early Discharge length of Hospital Stay
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不同结构参数下的半U形地下空间烟气运动参数的机器学习预测
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作者 徐志胜 殷耀龙 +2 位作者 雷志强 陈诗仪 应后淋 《灾害学》 北大核心 2025年第1期67-73,共7页
结合火灾数值模拟(FDS)与机器学习方法,该文对半U形地下空间火灾时的烟气运动进行了深入分析。研究发现,在预测烟气回流长度及烟气最高温升方面,BP神经网络相比于支持向量机回归(SVR)展现了更高的精度,其决定系数超过了95%,而相对误差... 结合火灾数值模拟(FDS)与机器学习方法,该文对半U形地下空间火灾时的烟气运动进行了深入分析。研究发现,在预测烟气回流长度及烟气最高温升方面,BP神经网络相比于支持向量机回归(SVR)展现了更高的精度,其决定系数超过了95%,而相对误差仅集中在20%以内,显著优于SVR方法。通过shap值解释机器学习模型,并结合FDS数值模拟的结果,揭示坡高是影响烟气回流长度的决定性因素,且坡高的增大、宽度的减小或热释放速率增大均会缩短烟气回流。同时,热释放速率是影响烟气最高温升的主要因素,受坡高影响较大,而宽度的减小虽能在一定幅度上降低最高烟气温升,但效果并不显著。该研究拓展了地下空间火灾烟气运动参数的预测方法,为地下空间火灾动力学行为预测及通风排烟系统的优化设计贡献了创新性的方法。 展开更多
关键词 半U形地下空间 机器学习 截面宽度 坡高 烟气回流长度 最高烟气温升
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Genetic analysis of fruit shape traits at different maturation stages in sponge gourd 被引量:6
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作者 ZHANG Sheng HU Jin ZHANG Cai-fang GUAN Ya-jing ZHANG Ying 《Journal of Zhejiang University-Science B(Biomedicine & Biotechnology)》 SCIE CAS CSCD 2007年第5期338-344,共7页
The fruit shape is important quantitative trait closely related to the fruit quality. However, the genetic model of fruit shapes has not been proposed. Therefore, in the present study, analysis of genetic effects for ... The fruit shape is important quantitative trait closely related to the fruit quality. However, the genetic model of fruit shapes has not been proposed. Therefore, in the present study, analysis of genetic effects for fruit shape traits (fruit length and fruit perimeter) in sponge gourd was conducted by employing a developmental genetic model including fruit direct effects and maternal effects. Analysis approaches of unconditional and conditional variances were applied to evaluate the genetic behavior of fruit shape traits at economical and physiological maturation times. The results of variance analysis indicated that fruit length and fruit perimeter were simultaneously affected by fruit direct genetic effects and maternal effects. Fruit direct genetic effects were relatively more important for fruit shape traits at whole developmental period. The gene expression was most active at the economical maturation stage (1-12 d after flowering) for two shape traits, and the activation of gene was mostly due to direct dominance effects at physiological maturation stage (13-60 datter flowering). The coefficients due to different genetic effects, as well as the phenotypic correlation coefficients, varied significantly between fruit shape traits themselves at various maturation stages. The results showed that it was relatively easy to improve fruit shape traits for industrial purpose by carefully selecting the parents at economical maturation stage instead of that at physiological maturation stage. 展开更多
关键词 Fruit length Fruit perimeter Genetic effects Genetic variance Luffa cylindrical Roem
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Approximate Relativistic Solutions for One-Dimensional Cylindrical Coaxial Diode 被引量:1
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作者 曾正中 刘国治 邵浩 《Plasma Science and Technology》 SCIE EI CAS CSCD 2002年第1期1093-1100,共8页
Two approximate analytical relativistic solutions for one-dimensional, space-charge- limited cylindrical coaxial diode are derived and utilized to compose best-fitting approximate solutions. Comparison of the best-fit... Two approximate analytical relativistic solutions for one-dimensional, space-charge- limited cylindrical coaxial diode are derived and utilized to compose best-fitting approximate solutions. Comparison of the best-fitting solutions with the numerical one demonstrates an error of about 11% for cathode-inside arrangement and 12% in the cathode-outside case for ratios of larger to smaller electrode radius from 1.2 to 10 and a voltage above 0.5 MV up to 5 MV. With these solutions the diode lengths for critical self-magnetic bending and for the condition under which the parapotential model validates are calculated to be longer than 1 cm up to more than 100 cm depending on voltage, radial dimensions and electrode arrangement. The influence of ion flow from the anode on the relativistic electron-only solution is numerically computed, indicating an enhancement factor of total diode current of 1.85 to 4.19 related to voltage, radial dimension and electrode arrangement. 展开更多
关键词 Approximate Relativistic Solutions for One-Dimensional cylindrical Coaxial Diode length MV
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