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Safety Performance Functions for Traffic Signals:Phasing and Geometry
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作者 Shane Turner 《Journal of Civil Engineering and Architecture》 2023年第4期199-213,共15页
A significant proportion of urban crashes,especially serious and fatal crashes,occur at traffic signals.Many of the black-spots in both Australia and New Zealand cities occur at high volume and/or high-speed traffic s... A significant proportion of urban crashes,especially serious and fatal crashes,occur at traffic signals.Many of the black-spots in both Australia and New Zealand cities occur at high volume and/or high-speed traffic signals.Given this,crash reduction studies often focus on the major signalised intersections.However,there is limited information that links the phasing configuration,degree of saturation and overall cycle time to crashes.While a number of analysis tools are available for assessing the efficiency of intersections,there are very few tools that can assist engineers in assessing the safety effects of intersection upgrades and new intersections.Safety performance functions have been developed to help quantify the safety impact of various traffic signal phasing configurations and level of intersection congestion at low and high-speed traffic signals in New Zealand and Australia.Data from 238 signalised intersection sites in Auckland,Wellington,Christchurch,Hamilton,Dunedin and Melbourne was used to develop crash prediction models for key crash-causing movements at traffic signals.Different variables(road features)effect each crash type.The models indicate that the safety of intersections can be improved by longer cycle times and longer lost inter-green times,especially all-red time,using fully protected right turns and by extending the length of right turn bays.The exception is at intersections with lots of pedestrians where shorter cycle times are preferred as pedestrian crashes increase with longer wait times.A number of factors have a negative impact on safety including,free left turns,more approach lanes,intersection arms operating near or over capacity in peak periods and higher speed limits. 展开更多
关键词 Crash/Accident prediction models generalized linear models traffic signal layout and phasing pedestrian safety and safety performance functions
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Enhancement of MAD/MIR phasing at low resolution and a new procedure for automatic phase extension
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作者 韩普 古元新 +1 位作者 丁玮 范海福 《Chinese Physics B》 SCIE EI CAS CSCD 2019年第7期389-395,共7页
To achieve de novo protein structure determination of challenging cases, multi-wavelength anomalous diffraction(MAD) and multiple isomorphous replacement(MIR) phasing can be powerful tools to obtain low-resolution ini... To achieve de novo protein structure determination of challenging cases, multi-wavelength anomalous diffraction(MAD) and multiple isomorphous replacement(MIR) phasing can be powerful tools to obtain low-resolution initial phases from heavy-atom derivative datasets, then phase extension is needed against high-resolution data to obtain accurate structures.In this context, we propose a direct-methods procedure here that could improve the initial low-resolution MAD/MIR phase quality.And accordingly, an automated process for extending initial phases to high resolution is also described.These two procedures are both implanted in the newly released IPCAS pipeline.Three cases are used to perform the test, including one set of 4.17 ? MAD data from a membrane protein and two sets of MAD/MIR data with derivatives truncated down to 6.80 ? and 6.90 ?, respectively.All the results have shown that the initial phases generated from the direct-methods procedure are better than that from the conventional MAD/MIR methods.The automated phase extensions for the latter two cases starting from 6.80 ? to 3.00 ? and 6.90 ? to 2.80 ? are proved to be successful, leading to complete models.This may provide convenient and reliable tools for phase improvement and phase extension in difficult low-resolution tasks. 展开更多
关键词 direct methods MULTI-WAVELENGTH anomalous diffraction(MAD)/multiple isomorphous replacement(MIR) phasing PHASE EXTENSION low-resolution
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Method for Collision Avoidance in Spacecraft Rendezvous Problems with Space Objects in a Phasing Orbit
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作者 Danhe Chen A.A.Baranov +2 位作者 Chuangge Wang M.O.Karatunov N.Yu.Makarov 《Computer Modeling in Engineering & Sciences》 SCIE EI 2021年第6期977-991,共15页
As the number of space objects(SO)increases,collision avoidance problem in the rendezvous tasks or reconstellation of satellites with SO has been paid more attention,and the dangerous area of a possible collision shou... As the number of space objects(SO)increases,collision avoidance problem in the rendezvous tasks or reconstellation of satellites with SO has been paid more attention,and the dangerous area of a possible collision should be derived.In this paper,a maneuvering method is proposed for avoiding collision with a space debris object in the phasing orbit of the initial optimal solution.Accordingly,based on the plane of eccentricity vector components,relevant dangerous area which is bounded by two parallel lines is formulated.The axises of eccentricity vector system pass through the end of eccentricity vector of phasing orbit in the optimal solution,and orientation of axis depends on the latitude argument where a collision will occur.The dangerous area is represented especially with the graphical dialogue,and it allows to find a compromise between the SO avoiding and the fuel consumption reduction.The proposed method to solve the collision avoidance problem provides simplicity to calculate rendezvous maneuvers,and possibility to avoid collisions from several collisions or from“slow”collisions in a phasing orbit,when the protected spacecraft and the object fly dangerously close to each other for a long period. 展开更多
关键词 SPACECRAFT collision avoidance rendezvous problem space objects phasing orbit
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Ce-SAD Phasing of Glucose Isomerase and Thermolysin Using Cu <i>Kα</i>Radiation
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作者 Sibi Narayanan Devadasan Velmurugan 《Crystal Structure Theory and Applications》 2013年第3期93-99,共7页
Current structural genomics projects aim to solve a large number of selected protein structures as fast as possible. High degree of automation and standardization is required at every step of the whole process to spee... Current structural genomics projects aim to solve a large number of selected protein structures as fast as possible. High degree of automation and standardization is required at every step of the whole process to speed up protein structure determination. Phase problem is a bottleneck in macromolecular structure determination and also in model building which is a time-consuming task. The simplest approach to phasing macromolecular crystal structures is the use of a SAD signal. SAD data can be collected using the in-house copper (1.54 A) wavelength source. Data collected using copper wavelength with the incorporation of anomalously scattering heavy metal atoms may serve as a powerful tool for structural biologists to solve novel protein structures as well where synchrotron beam line is not available. A short soak of protein crystals in heavy metal solution or by incorporating heavy atoms into the protein drop while crystallizing the protein (co-crystallization) leads to incorporation of these heavy metal ions into the ordered solvent shell around the protein surface. The present work aims to determine whether cerium ion can be successfully incorporated into the protein crystal through quick-soaking method while maintaining the isomorphism. The study also aims in understanding whether this metal ion can be used for phasing purpose. The intensity data are collected and analyzed for anomalous signal, substructure solution and the binding sites. 展开更多
关键词 Anomalous Scattering SAD phasing CE Glucose ISOMERASE THERMOLYSIN
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Dephasing Measurements in InGaAs/AlInAs Heterostructures: Manifestations of Spin-Orbit and Zeeman Interactions
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作者 Lior H. Tzarfati Rafi Hevroni +5 位作者 Amnon Aharony Ora Entin-Wohlman Michael Karpovski Victor Shelukhin Vladimir Umansky Alexander Palevski 《Journal of Modern Physics》 2017年第1期110-125,共16页
We have measured weak antilocalization effects, universal conductance fluctuations, and Aharonov-Bohm oscillations in the two-dimensional electron gas formed in InGaAs/AlInAs heterostructures. This system possesses st... We have measured weak antilocalization effects, universal conductance fluctuations, and Aharonov-Bohm oscillations in the two-dimensional electron gas formed in InGaAs/AlInAs heterostructures. This system possesses strong spin-orbit coupling and a high Landé factor. Phase-coherence lengths of 2 - 4 μm at 1.5 - 4.2 K are extracted from the magnetoconductance measurements. The analysis of the coherence-sensitive data reveals that the temperature dependence of the decoherence rate complies with the dephasing mechanism originating from electron-electron interactions in all three experiments. Distinct beating patterns superimposed on the Aharonov-Bohm oscillations are observed over a wide range of magnetic fields, up to 0.7 Tesla at the relatively high temperature of 1.5 K. The possibility that these beats are due to the interplay between the Aharonov-Bohm phase and the Berry one, different for electrons of opposite spins in the presence of strong spin-orbit and Zeeman interactions in ring geometries, is carefully investigated. It appears that our data are not explained by this mechanism;rather, a few geometrically-different electronic paths within the ring’s width can account for the oscillations’ modulations. 展开更多
关键词 MESOSCOPIC Physics DECOHERENCE Aharonov BOHM Spin Orbit Interaction Berry Phase
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Left-turn phasing selection considering vehicle to vehicle and vehicle to pedestrian conflicts
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作者 Kakan C.Dey Md Tawhidur Rahman +1 位作者 Subasish Das Amrit Manova Williams 《Journal of Traffic and Transportation Engineering(English Edition)》 EI CSCD 2023年第1期58-69,共12页
Left-turning vehicle movement at signalized intersections with permissive left-turn phases creates safety concerns due to the higher chance of conflict with opposing-through vehicles and pedestrians.In this research,a... Left-turning vehicle movement at signalized intersections with permissive left-turn phases creates safety concerns due to the higher chance of conflict with opposing-through vehicles and pedestrians.In this research,a simulation-based study was conducted to evaluate pedestrians’impact on traffic conflicts between left-turning vehicles and opposing-through vehicles(V-V conflicts)as well as traffic conflicts between left-turning vehicles and pedestrians(V-P conflicts)in the permissive left-turn phasing scenario.Intersections with different opposing-through volumes,left-turn volumes,number of opposing-through lanes,and pedestrian volumes were modeled in VISSIM,a traffic micro-simulator.The surrogate safety assessment model(SSAM)was used to estimate the number of V-V and VP conflicts.The effect of pedestrian presence on V-V and V-P conflicts was evaluated using simulation scenarios with and without pedestrian presence.Simulation results revealed that pedestrian presence increased both V-V and V-P conflicts.As pedestrian presence increased the total number of traffic conflicts,permissive left-turn phasing processed fewer left-turn vehicles to maintain the same level of intersection safety with pedestrian presence compared to the no-pedestrian scenario.Since current left-turn phasing decision guidelines do not consider the impacts of pedestrian presence,this research quantified pedestrian-influenced and pedestrian-involved left-turn traffic conflicts to determine appropriate left-turn signal phasing decisions to ensure safe and efficient crossing of pedestrians and vehicles at signalized intersections.This simulation-based study’s findings can be beneficial in the decision making of left-turn phasing selection as the before-after intersection safety performance analysis by collecting field data often resources intensive. 展开更多
关键词 V-V conflicts V-P conflicts Left-turn phasing PEDESTRIAN WARRANTS
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基于CTA颅内动脉瘤形态联合PHASES评分对破裂出血预测研究
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作者 王金泉 黄吉淮 谢颖 《影像研究与医学应用》 2024年第4期31-34,共4页
目的:分析头颈部计算机断层扫描血管成像(CTA)联合PHASES评分对颅内动脉瘤(IA)破裂出血的预测价值。方法:回顾性分析2021年10月—2023年9月东莞市长安医院诊治的IA患者临床资料,根据IA破裂出血与否分为IA破裂组(n=46)和IA未破裂组(n=44)... 目的:分析头颈部计算机断层扫描血管成像(CTA)联合PHASES评分对颅内动脉瘤(IA)破裂出血的预测价值。方法:回顾性分析2021年10月—2023年9月东莞市长安医院诊治的IA患者临床资料,根据IA破裂出血与否分为IA破裂组(n=46)和IA未破裂组(n=44),收集两组临床资料,对比两组患者CTA影像瘤体特征参数和PHASES评分结果。采用受试者工作特征(ROC)曲线分析两者联合预测动脉瘤破裂的效能。结果:IA破裂组高血压、糖尿病发生率及PHASES评分均高于IA未破裂组,差异有统计学意义(P <0.05)。两组病灶位置以颈内动脉(ICA)和大脑中动脉(MCA)为主,但IA破裂组病灶位置在MCA的占比为41.30%,高于IA未破裂组的20.45%,瘤体>7 mm的最多(瘤体7~9.9 mm占65.22%),瘤体形态不规则占58.7%,未破裂组病灶位置在ICA最多(68.18%),瘤体<7 mm的居多(75.00%),瘤体形态规则囊状动脉瘤占93.18%,差异有统计学意义(P <0.05)。CTA瘤体特征参数比较,IA破裂组患者瘤颈宽度、瘤体高度、瘤体长度、动脉瘤最大直径、入射夹角、动脉瘤体颈比等参数均高于IA未破裂组,差异有统计学意义(P <0.05)。CTA瘤体特征参数+PHASES评分联合预测曲线下面积为0.916,高于CTA瘤体特征参数(0.901)和PHASES评分(0.731)。结论:CTA瘤体特征参数+PHASES评分联合预测IA患者破裂出血效能最佳。 展开更多
关键词 颅内动脉瘤 破裂出血 CTA PHASES评分
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Multi-isomorphous replacement phasing of the earthworm fibrinolytic enzyme component A from Eisenia fetida 被引量:1
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作者 汤涌 江涛 +4 位作者 张季平 樊蓉 吴骋 梁栋材 常文瑞 《Science China(Life Sciences)》 SCIE CAS 2003年第3期263-272,共10页
Earthworm fibrinolytic enzyme component A (EFEa) from Eisenia fetida, a protein func-tioning not only as a direct fibrinolytic enzyme, but also as a plasminogen activator, has been crystallized in P212121 space group ... Earthworm fibrinolytic enzyme component A (EFEa) from Eisenia fetida, a protein func-tioning not only as a direct fibrinolytic enzyme, but also as a plasminogen activator, has been crystallized in P212121 space group with 3 protein molecules per asymmetric unit. Four heavy atom derivatives were prepared using a mother liquor containing 1.4 mol·L-1 Li2SO4 and 0.1 mol·L-1 MOPS buffer (pH7.2) and used to solve the protein抯 diffraction phase. The heavy atom binding sites in the derivative crystals were determined using difference Patterson and difference Fourier methods and were refined in combination to yield the initial protein抯 structure phase at 0.25 nm resolution. The non-crystallographic symmetry relationship of the three independent protein mole-cules in the asymmetric unit was determined using the correlative heavy atom sites and used for the averaging of the initial electron density. As a result, the electron density was significantly im-proved, providing a solid foundation for subsequent structure determination. 展开更多
关键词 Eisenia fetida EARTHWORM FIBRINOLYTIC enzyme plasminogen activator multi-isomorphous replacement phasing.
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Energy conservation in China's coal-fired power industry by installing advanced units and organized phasing out backward production 被引量:1
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作者 Weiliang WANG Junfu LYU +3 位作者 Zheng LI Hai ZHANG Guangxi YUE Weidou NI 《Frontiers in Energy》 SCIE CSCD 2019年第4期798-807,共10页
Coal-fired power is the main power source and the biggest contributor to energy conservation in the past several decades in China.It is generally believed that advanced technology should be counted on for energy conse... Coal-fired power is the main power source and the biggest contributor to energy conservation in the past several decades in China.It is generally believed that advanced technology should be counted on for energy conservation.However,a review of the decline in the national average net coal consumption rate(NCCR)of China's coal-fired power industry along with its development over the past few decades indicates that the upgradation of the national unit capacity structure(including installing advanced production and phasing out backward production)plays a more important role.A quantitative study on the effect of the unit capacity structure upgradation on the decline in the national average NCCR suggests that phasing out backward production is the leading factor for the decline in the NCCR in the past decade,followed by the new installation,whose sum contributes to approximately 80%of the decline in the national average NCCR.The new installation has an effective affecting period of about 8 years,during which it would gradually decline from a relatively high value.Since the effect of phasing out backward production may remain at a certain degree given a continual action of phasing out backward capacity,it is suggested that the organized action of phasing out backward production should be insisted on. 展开更多
关键词 coal-fired power energy conservation net coal consumption rate new installation phasing out backward production unit capacity structure
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Experimental demonstration of suppressing residual geometric dephasing 被引量:1
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作者 Jin-Ming Cui Ming-Zhong Ai +7 位作者 Ran He Zhong-Hua Qian Xiao-Ke Qin Yun-Feng Huang Zheng-Wei Zhou Chuan-Feng Li Tao Tu Guang-Can Guo 《Science Bulletin》 SCIE EI CAS CSCD 2019年第23期1757-1763,共7页
The geometric phase is regarded as a promising strategy in fault tolerance quantum information processing(QIP) domain due to its phase only depending on the geometry of the path executed. However, decoherence caused b... The geometric phase is regarded as a promising strategy in fault tolerance quantum information processing(QIP) domain due to its phase only depending on the geometry of the path executed. However, decoherence caused by environmental noise will destroy the geometric phase. Traditional dynamic decoupling sequences can eliminate dynamic dephasing but can not reduce residual geometric dephasing, which is still vital for high-precision quantum manipulation. In this work, we experimentally demonstrate effective suppression of residual geometric dephasing with modified dynamic decoupling schemes,using a single trapped171 Ybtion. The experimental results show that the modified schemes can reduce dephasing rate up to more than one order of magnitude compared with traditional dynamic decoupling schemes, where residual geometric dephasing dominates. Besides, we also investigate the impact of intensity and correlation time of the low-frequency noise on coherence of the quantum system. And we confirm these methods can be used in many cases. 展开更多
关键词 Geometric dephasing Berry phase Dynamic decoupling Ion trap
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In situ observation of the phase transformation kinetics of bismuth during shock release
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作者 李江涛 王倩男 +7 位作者 徐亮 柳雷 张航 Sota Takagi Kouhei Ichiyanagi Ryo Fukaya Shunsuke Nozawa 胡建波 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第4期586-592,共7页
A time-resolved x-ray diffraction technique is employed to monitor the structural transformation of laser-shocked bismuth.Results reveal a retarded transformation from the shock-induced Bi-Ⅴphase to a metastable Bi-... A time-resolved x-ray diffraction technique is employed to monitor the structural transformation of laser-shocked bismuth.Results reveal a retarded transformation from the shock-induced Bi-Ⅴphase to a metastable Bi-Ⅳphase during the shock release,instead of the thermodynamically stable Bi-Ⅲphase.The emergence of the metastable Bi-Ⅳphase is understood by the competitive interplay between two transformation pathways towards the Bi-Ⅳand Bi-Ⅲ,respectively.The former is more rapid than the latter because the Bi-Ⅴto B-Ⅳtransformation is driven by interaction between the closest atoms while the Bi-Ⅴto B-Ⅲtransformation requires interaction between the second-closest atoms.The nucleation time for the Bi-Ⅴto Bi-Ⅳtransformation is determined to be 5.1±0.9 ns according to a classical nucleation model.This observation demonstrates the importance of the formation of the transient metastable phases,which can change the phase transformation pathway in a dynamic process. 展开更多
关键词 phase transformation time-resolved x-ray diffraction(XRD) BISMUTH metastable phase nonequilibrium phase diagram
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Kinematic analysis of flexible bipedal robotic systems
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作者 R.FAZEL A.M.SHAFEI S.R.NEKOO 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2024年第5期795-818,共24页
In spite of its intrinsic complexities,the passive gait of bipedal robots on a sloping ramp is a subject of interest for numerous researchers.What distinguishes the present research from similar works is the considera... In spite of its intrinsic complexities,the passive gait of bipedal robots on a sloping ramp is a subject of interest for numerous researchers.What distinguishes the present research from similar works is the consideration of flexibility in the constituent links of this type of robotic systems.This is not a far-fetched assumption because in the transient(impact)phase,due to the impulsive forces which are applied to the system,the likelihood of exciting the vibration modes increases considerably.Moreover,the human leg bones that are involved in walking are supported by viscoelastic muscles and ligaments.Therefore,for achieving more exact results,it is essential to model the robot links with viscoelastic properties.To this end,the Gibbs-Appell formulation and Newton's kinematic impact law are used to derive the most general form of the system's dynamic equations in the swing and transient phases of motion.The most important issue in the passive walking motion of bipedal robots is the determination of the initial robot configuration with which the system could accomplish a periodic and stable gait solely under the effect of gravitational force.The extremely unstable nature of the system studied in this paper and the vibrations caused by the impulsive forces induced by the impact of robot feet with the inclined surface are some of the very serious challenges encountered for achieving the above-mentioned goal.To overcome such challenges,an innovative method that uses a combination of the linearized equations of motion in the swing phase and the algebraic motion equations in the transition phase is presented in this paper to obtain an eigenvalue problem.By solving this problem,the suitable initial conditions that are necessary for the passive gait of this bipedal robot on a sloping surface are determined.The effects of the characteristic parameters of elastic links including the modulus of elasticity and the Kelvin-Voigt coefficient on the walking stability of this type of robotic systems are also studied.The findings of this parametric study reveal that the increase in the Kelvin-Voigt coefficient enhances the stability of the robotic system,while the increase in the modulus of elasticity has an opposite effect. 展开更多
关键词 bipedal robot flexible link swing phase transient phase eigenvalue problem Kelvin-Voigt coefficient
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Phase-engineering modulation of Mn-based oxide cathode for constructing super-stable sodium storage
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作者 Quanqing Zhao Ruru Wang +5 位作者 Ming Gao Bolin Liu Jianfeng Jia Haishun Wu Youqi Zhu Chuanbao Cao 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2024年第1期421-427,I0010,共8页
The Mn-based oxide cathode with enriched crystal phase structure and component diversity can provide the excellent chemistry structure for Na-ion batteries.Nevertheless,the broad application prospect is obstructed by ... The Mn-based oxide cathode with enriched crystal phase structure and component diversity can provide the excellent chemistry structure for Na-ion batteries.Nevertheless,the broad application prospect is obstructed by the sluggish Na^(+)kinetics and the phase transitions upon cycling.Herein,we establish the thermodynamically stable phase diagram of various Mn-based oxide composites precisely controlled by sodium content tailoring strategy coupling with co-doping and solid-state reaction.The chemical environment of the P2/P'3 and P2/P3 biphasic composites indicate that the charge compensation mechanism stems from the cooperative contribution of anions and cations.Benefiting from the no phase transition to scavenge the structure strain,P2/P'3 electrode can deliver long cycling stability(capacity retention of 73.8%after 1000 cycles at 10 C)and outstanding rate properties(the discharge capacity of 84.08 mA h g^(-1)at 20 C)than P2/P3 electrode.Furthermore,the DFT calculation demonstrates that the introducing novel P'3 phase can significantly regulate the Na^(+)reaction dynamics and modify the local electron configuration of Mn.The effective phase engineering can provide a reference for designing other high-performance electrode materials for Na-ion batteries. 展开更多
关键词 Sodium ion battery Oxide cathode Phase engineering Phase diagram Na~+kinetic
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Phasing analysis of the transcriptome and epigenome in a rice hybrid reveals the inheritance and difference in DNA methylation and allelic transcription regulation 被引量:1
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作者 Jia-Wu Feng Yue Lu +3 位作者 Lin Shao Jianwei Zhang Huan Li Ling-Ling Chen 《Plant Communications》 2021年第4期52-65,共14页
Hybrids are always a focus of botanical research and have a high practical value in agricultural production.To better understand allele regulation and differences in DNA methylation in hybrids,we developed a phasing p... Hybrids are always a focus of botanical research and have a high practical value in agricultural production.To better understand allele regulation and differences in DNA methylation in hybrids,we developed a phasing pipeline for hybrid rice based on two parental genomes(PP2PG),which is applicable for Iso-Seq,RNA-Seq,and Bisulfite sequencing(BS-Seq).Using PP2PG,we analyzed differences in gene transcription,alternative splicing,and DNA methylation in an allele-specific manner between parents and progeny or different progeny alleles.The phasing of Iso-Seq data provided a great advantage in separating the whole gene structure and producing a significantly higher separation ratio than RNA-Seq.The interaction of hybrid alleles was studied by constructing an allele co-expression network that revealed the dominant allele effect in the network.The expression variation between parents and the parental alleles in progeny showed tissue-or environment-specific patterns,which implied a preference for trans-acting regulation under different conditions.In addition,by comparing allele-specific DNA methylation,we found that CG methylation was more likely to be inherited than CHG and CHHmethylation,and its enrichment in genic regions was connected to gene structure.In addition to an effective phasing pipeline,we also identified differentiation in OsWAK38 gene structure that may have led to the expansion of allele functions in hybrids.In summary,we developed a phasing pipeline and provided valuable insights into alternative splicing,interaction networks,trans-acting regulation,and the inheritance of DNA methylation in hybrid rice. 展开更多
关键词 phasing HYBRID trans-acting regulation allele co-expression network allele-specific expression allele-specific DNA methylation
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采用PHASE2软件的隧洞一次支护数值模拟与分析
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作者 刘卓 穆全平 《水科学与工程技术》 2024年第1期37-39,共3页
处于V类围岩的隧洞施工时,通常要采取一次支护以保证围岩稳定。采用PHASE2岩土工程弹塑性有限元分析软件,对某引调水工程中处于V类围岩的隧洞围岩位移与塑性区分布进行模拟分析。结果表明:在不采取支护措施情况下,隧洞施工时将发生坍塌... 处于V类围岩的隧洞施工时,通常要采取一次支护以保证围岩稳定。采用PHASE2岩土工程弹塑性有限元分析软件,对某引调水工程中处于V类围岩的隧洞围岩位移与塑性区分布进行模拟分析。结果表明:在不采取支护措施情况下,隧洞施工时将发生坍塌破坏,具有极大的安全隐患;在采取拟定措施后,围岩总位移满足规范要求,且未发生塑性破坏,因此支护后隧洞达到稳定且安全的状态,验证支护措施的有效性。但为保证工程安全,建议施工期间做好排水措施,并缩短施工开挖、一次支护措施之间的施工间隔,使支护尽早发挥作用。 展开更多
关键词 隧洞开挖 一次支护 PHASE2 数值模拟
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Revealing the atomic mechanism of diamond–iron interfacial reaction
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作者 Yalun Ku Kun Xu +6 位作者 Longbin Yan Kuikui Zhang Dongsheng Song Xing Li Shunfang Li Shaobo Cheng Chongxin Shan 《Carbon Energy》 SCIE EI CAS CSCD 2024年第3期255-263,共9页
Diamond,with ultrahigh hardness,high wear resistance,high thermal conductivity,and so forth,has attracted worldwide attention.However,researchers found emergent reactions at the interfaces between diamond and ferrous ... Diamond,with ultrahigh hardness,high wear resistance,high thermal conductivity,and so forth,has attracted worldwide attention.However,researchers found emergent reactions at the interfaces between diamond and ferrous materials,which significantly affects the performance of diamond-based devices.Herein,combing experiments and theoretical calculations,taking diamond–iron(Fe)interface as a prototype,the counter-diffusion mechanism of Fe/carbon atoms has been established.Surprisingly,it is identified that Fe and diamond first form a coherent interface,and then Fe atoms diffuse into diamond and prefer the carbon vacancies sites.Meanwhile,the relaxed carbon atoms diffuse into the Fe lattice,forming Fe_(3)C.Moreover,graphite is observed at the Fe_(3)C surface when Fe_(3)C is over-saturated by carbon atoms.The present findings are expected to offer new insights into the atomic mechanism for diamondferrous material's interfacial reactions,benefiting diamond-based device applications. 展开更多
关键词 coherent interface counter-diffusion DIAMOND IRON phase transition
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Microstructure Characteristics and Elevated Temperature Mechanical Properties of a B Containedβ-solidifiedγ-TiAl Alloy
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作者 王秀琦 GUO Ruiqi +5 位作者 刘国怀 LI Tianrui YANG Yuxuan CHEN Yang XIN Meiling WANG Zhaodong 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS CSCD 2024年第3期738-746,共9页
The improved microstructure and enhanced elevated temperature mechanical properties of Ti-44Al-5Nb-(Mo,V,B)alloys were obtained by vacuum arc re-melting(VAR)and primary annealing heat treatment(HT)of 1260℃/6 h/Furnac... The improved microstructure and enhanced elevated temperature mechanical properties of Ti-44Al-5Nb-(Mo,V,B)alloys were obtained by vacuum arc re-melting(VAR)and primary annealing heat treatment(HT)of 1260℃/6 h/Furnace cooling(FC).The phase transformation,microstructure evolution and tensile properties for as-cast and HTed alloys were investigated.Results indicate that three main phase transformation points are determined,T_(eut)=1164.3℃,T_(γsolv)=1268.3℃and T_(βtrans)=1382.8℃.There are coarse lamellar colonies(300μm in length)and neighbor reticular B2 andγgrain(3-5μm)in as-cast alloy,while lamellar colonies are markedly refined and multi-oriented(20-50μm)as well as the volume fraction and grain sizes of equiaxedγand B2 phases(about 15μm)significantly increase in as-HTed alloy.Phase transformations involvingα+γ→α+γ+β/B2 and discontinuousγcoarsening contribute to the above characteristics.Borides(1-3μm)act as nucleation sites forβ_(eutectic) and produce massiveβgrains with different orientations,thus effectively refining the lamellar colonies and forming homogeneous multi-phase microstructure.Tensile curves show both the alloys exhibit suitable performance at 800℃.As-cast alloy shows a higher ultimate tensile stress of 647 MPa,while a better total elongation of more than 41%is obtained for as-HTed alloy.The mechanical properties improvement is mainly attributed to fine,multi-oriented lamellar colonies,coordinated deformation of homogeneous multi-phase microstructure and borides within lamellar interface preventing crack propagation. 展开更多
关键词 TiAl alloy phase transformation heat treatment BORIDE microstructure mechanical properties
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Chimera states of phase oscillator populations with nonlocal higher-order couplings
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作者 伍勇刚 余华健 +1 位作者 郑志刚 徐灿 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第4期402-407,共6页
The chimera states underlying many realistic dynamical processes have attracted ample attention in the area of dynamical systems.Here, we generalize the Kuramoto model with nonlocal coupling incorporating higher-order... The chimera states underlying many realistic dynamical processes have attracted ample attention in the area of dynamical systems.Here, we generalize the Kuramoto model with nonlocal coupling incorporating higher-order interactions encoded with simplicial complexes.Previous works have shown that higher-order interactions promote coherent states.However, we uncover the fact that the introduced higher-order couplings can significantly enhance the emergence of the incoherent state.Remarkably, we identify that the chimera states arise as a result of multi-attractors in dynamic states.Importantly, we review that the increasing higher-order interactions can significantly shape the emergent probability of chimera states.All the observed results can be well described in terms of the dimension reduction method.This study is a step forward in highlighting the importance of nonlocal higher-order couplings, which might provide control strategies for the occurrence of spatial-temporal patterns in networked systems. 展开更多
关键词 synchronization complex system coupled oscillators phase transition
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Diet and monensin influence the temporal dynamics of the rumen microbiome in stocker and finishing cattle
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作者 Jianmin Chai Caleb P.Weiss +3 位作者 Paul A.Beck Wei Zhao Ying Li Jiangchao Zhao 《Journal of Animal Science and Biotechnology》 SCIE CAS CSCD 2024年第2期733-748,共16页
Background Stocker cattle diet and management influence beef cattle performance during the finishing stage,but knowledge of the dynamics of the rumen microbiome associated with the host are lacking.A longitudinal stud... Background Stocker cattle diet and management influence beef cattle performance during the finishing stage,but knowledge of the dynamics of the rumen microbiome associated with the host are lacking.A longitudinal study was conducted to determine how the feeding strategy from the stocker to the finishing stages of production affects the temporal dynamics of rumen microbiota.During the stocker phase,either dry hay or wheat pasture were provided,and three levels of monensin were administrated.All calves were then transported to a feedlot and received similar finishing diets with or without monensin.Rumen microbial samples were collected on d 0,28,85 during the stocker stage(S0,S28 and S85)and d 0,14,28,56,30 d before slaughter and the end of the trial during the finishing stage(F0,F14,F28,F56,Pre-Ba,and Final).The V4 region of the bacterial 16S rRNA gene of 263 rumen samples was sequenced.Results Higher alpha diversity,including the number of observed bacterial features and the Shannon index,was observed in the stocker phase compared to the finishing phase.The bacterial amplicon sequence variants(ASVs)differentiating different sampling time points were identified.Dietary treatments during the stocker stage temporally impact the dynamics of rumen microbiota.For example,shared bacteria,including Bacteroidales(ASV19)and Streptococcus infantarius(ASV94),were significantly higher in hay rumen on S28,S85,and F0,while Bacteroidaceae(ASV11)and Limivicinus(ASV15)were more abundant in wheat.Monensin affected rumen microbial composition at a specific time.Transportation to feedlot significantly influenced microbiome structure and diversity in hay-fed calves.Bacterial taxa associated with body weight were classified,and core microbiotas interacted with each other during the trial.Conclusions In summary,the temporal dynamics of the rumen microbiome in cattle at the stocker and finishing stage are influenced by multiple factors of the feeding strategy.Diet at the stocker phase may temporarily affect the microbial composition during this stage.Modulating the rumen microbiome in the steers at the stocker stage affects the microbial interactions and performance in the finishing stage. 展开更多
关键词 Beef cattle DIET Feedlot phase MONENSIN Next-generation sequencing Rumen microbiota Stocker
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In-Situ Atomic-Scale Observation of Brownmillerite to Ruddlesden-Popper Phase Transition Tuned by Epitaxial Strain in Cobaltites
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作者 林挺 高昂 +6 位作者 汤哲歆 林炜光 孙慕华 张庆华 王雪锋 郭尔佳 谷林 《Chinese Physics Letters》 SCIE EI CAS CSCD 2024年第4期152-158,共7页
Phase transitions involving oxygen ion extraction within the framework of the crystallographic relevance have been widely exploited for sake of superconductivity,ferromagnetism,and ion conductivity in perovskiterelate... Phase transitions involving oxygen ion extraction within the framework of the crystallographic relevance have been widely exploited for sake of superconductivity,ferromagnetism,and ion conductivity in perovskiterelated oxides.However,atomic-scale pathways of phase transitions and ion extraction threshold are inadequately understood.Here we investigate the atomic structure evolution of LaCoO_(3) films upon oxygen extraction and subsequent Co migration,focusing on the key role of epitaxial strain.The brownmillerite to Ruddlesden-Popper phase transitions are discovered to stabilize at distinct crystal orientations in compressive-and tensile-strained cobaltites,which could be attributed to in-plane and out-of-plane Ruddlesden-Popper stacking faults,respectively.A two-stage process from exterior to interior phase transition is evidenced in compressive-strained LaCoO_(2.5),while a single-step nucleation process leaving bottom layer unchanged in tensile-strained situation.Strain analyses reveal that the former process is initiated by an expansion in Co layer at boundary,whereas the latter one is associated with an edge dislocation combined with antiphase boundary.These findings provide a chemomechanical perspective on the structure regulation of perovskite oxides and enrich insights into strain-dependent phase diagram in epitaxial oxides films. 展开更多
关键词 STRAINED Phase OXIDES
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