摘要：This paper presents a two-wheeled differential spherical mobile robot in view of the problems that the motion of spherical robot is difficult to control and the sensor is limited by the spherical *** robot is simple in structure,flexible in motion and easy to *** kinematics and dynamics model of spherical mobile robot is established according to the structure of spherical mobile *** the basis of the adaptive neural sliding mode control,the trajectory tracking controller of the system is *** the simulation of the s-trajectory and circular trajectory tracking control of the spherical mobile robot,it is concluded that the spherical mobile robot is flexible in motion and easy to *** addition,the simulation results show that the adaptive neural sliding mode control can effectively track the trajectory of the spherical *** adaptive control eliminates the influence of unknown parameters and disturbances,and avoids the jitter of left and right wheels during the torque output.

摘要：提出了一种基于二代镍基单晶(SX)高温合金γ′相尺寸变化统计分析的SX高温合金固溶热处理最佳时间的选择方法。通过数值分析引入了微观结构均匀性ω,根据数据统计ω曲线可分为3个阶段:显著变化区、过渡区和稳态区。过渡区描述了固溶热处理时间选择的最佳范围。通过测量合金的γ′筏化和蠕变性能,验证了该方法的有效性。同时也通过第四代镍基SX高温合金验证了该方法的准确性。该方法能够有效地建立最优的热处理工艺,并为SX高温合金的设计和工程应用提供指导。

摘要：Rapid technological development and population growth are responsible for a series of imminent environmental problems and an ineluctable energy *** application of semiconductor nanomaterials in photocatalysis or photoelectrocatalysis(PEC)for either the degradation of contaminants in the environment or the generation of hydrogen as clean fuel is an effective approach to alleviate these ***,the efficiency of such processes remains suboptimal for real *** construction of a built-in electric field is considered to efficiently enhance carrier separation and reduce carrier recombination to improve catalytic *** the past decade,as a new method to enhance the built-in electric field,the piezoelectric effect from piezoelectric materials has been extensively *** this review,we provide an overview of the properties of piezoelectric materials and the mechanisms of piezoelectricity and ferroelectricity for a built-in electric ***,piezoelectric and ferroelectric polarization regulated built-in electric fields that mediate catalysis are ***,the applications of piezoelectric semiconductor materials are also highlighted,including degradation of pollutants,bacteria disinfection,water splitting for H2 generation,and organic *** conclude by discussing the challenges in the field and the exciting opportunities to further improve piezo-catalytic efficiency.

摘要：目的:探讨真实世界数据应用与研究者发起的临床研究存在的鸿沟及其原因,并收集不同利益相关者的建议。研究设计:该定性研究针对3类人群分别设计3个访谈提纲。使用建构主义扎根理论进行数据分析。研究地点:中国北京市的6家三甲医院(3家综合医院和3家专科医院)。研究对象:通过分层目的抽样,对来自12个临床科室的42名医生、5名信息科人员和4名临床管理者进行访谈。结果:目前,电子病历数据应用于临床研究的过程中存在鸿沟仍然是中国医院普遍存在的问题。缺乏数据互操作性、非结构化的电子病历记录以及对数据安全性的担忧,造成基于医院的真实世界数据应用受到限制。各方利益相关者给出的建议,包括更新医院信息系统、推进数据标准和建立独立的临床研究平台。结论:了解造成真实世界数据应用于临床研究出现障碍的原因并给出建议,有助于中国临床研究的发展。本研究认为,更新医院信息系统、推进资料标准化和建立临床研究平台,可以促进未来将真实世界数据应用于临床研究。

摘要：Aiming to resolve the technical problems of lower gas concentrations and a reduced effective drainage period caused by gas-drainage borehole fracture development, a flexible gel （FG） gas-drainage borehole sealing material was developed that adapts to borehole deformation. In this study, based on orthogonal tests, the effect of the ratio of material to water, stirring time and stirring speed on the viscosity, filtration property, water retention and pumpability of the FG were studied. The results indicate that the stirring speed, ratio of material to water and stirring time in turn increased the viscosity and the ratio of material to water, stirring time and stirring speed enhanced the filtration property and water retention. The FG pumps smoothly and achieves the optimal state of high water retention, low fluid loss and low viscosity when the ratio of material to water is 1：10, the stirring speed is 800 r/min, and the stirring time is 12 min. The field test results indicate that, after using the FG, the average drainage gas concentration increases by 25.9% and 27.6g and the average negative pressure of extraction increases by 2.7 kPa and 3.5 kPa com- pared with expansive cement and polyurethane, respectively.

摘要：Each conventional alloy has its own specific compositions but the compositional origin is largely unknown due to our insufficient understanding about chemical shortrange ordering in the alloy,in particular,in the solid-solution *** the present paper,the compositions of metallic alloys are discussed and formulated,by unveiling the basic moleculelike structural units in solid *** oscillation theory,which describes the partial charge screening behavior in solid solutions,and henceforth the origin of short-range ordering,is applied to pin down the ideal chemical compositions of conventional metallic *** propose that,at a specific composition,atoms self-assemble into an ideally ordered structure consisting of atoms residing in the nearestneighbor shell(denoted as cluster)plus those in the next outer shell(denoted as glue atoms),which can be formulated as[cluster](glue atoms).This simplified version of short-rangeorder structure represents the smallest charge-neutral and mean-density zone(termed as“chemical units”)and can be regarded as the‘molecules’of solid ***,the chemical units and the corresponding molecule-like formulas for face-centered-cubic(FCC),hexagonal close-packed(HCP),and body-centered cubic(BCC)structures are analyzed and equations are obtained to identify the chemical formulas for FCC solid *** instance,well-knownα-brass Cu-30 Zn alloy is formulated as[Zn-Cu_(12)]*** of aluminum alloys,superalloys and stainless steels are also illustrated,demonstrating the versatility of the present model to interpret chemically complex alloys.

摘要：Bio-nanochannels in living organisms participate in the physiological activities by selectively transporting ions through cell *** structure and function of biological ion channels inspire the development of artificial ion nanochannels with practical *** bioinspired nanochannels based on polymer materials present good mechanical stability,high-performance ion transport and designability,which have attracted much *** this review,we mainly focus on the fabrication and application of polymer-based biomimetic nanochannels especially in environmentally responsive biosensor and energy *** firstly introduce the basic understanding of nanochannels in ion regulation and osmotic energy ***,we discuss the fabrication methods of polymer-based nanochannels and highlight their advantages compared with other *** practical applications of polymer-based biomimetic nanochannels,especially in energy conversion and environmentally responsive biosensor,are detailedly ***,we summarize the unsolved problems in bioinspired nanochannels and overview the further developing direction in this field.

摘要：Dynamic exploration for oil and gas requires careful monitoring of reservoir contents for safety and efficiency of oil extraction. This paper proposes a multi-source and multi-azimuth walk-around vertical electromagnetic profiling （MM-VEP） technique for surface-to-borehole electromagnetic surveying. Based on the difference in conductivities between reservoirs with different concentrations of oil and water, MM-VEP can be used to monitor reservoirs as they are injected with water. The MM-VEP response in five azimuth planes is modeled with three-dimensional （3D） integral equation calculations. The progress of waterflooding in four stages for enhanced oil recovery is shown to be indicated by field anomalies MM-VEP caused by variations in the reservoir resistivity. Numerical modeling demonstrates that MM-VEP measurements provides enough quantitative information from an underground reservoir to accurately detect oil deposits and monitor the progress of waterflooding.

摘要：根据对近年来公路路线设计的总结 ,从汽车行驶的安全性、舒适性出发 ,通过计算和对比分析 ,对平竖曲线半径的设置提出建议。

摘要：According to the Chapman multi-scale rock physical model, the seismic response characteristics vary for different fluid-saturated reservoirs. For class I AVO reservoirs and gas-saturation, the seismic response is a high-frequency bright spot as the amplitude energy shifts. However, it is a low-frequency shadow for the Class III AVO reservoirs saturated with hydrocarbons. In this paper, we verified the high-frequency bright spot results of Chapman for the Class I AVO response using the frequency-dependent analysis of a physical model dataset. The physical model is designed as inter-bedded thin sand and shale based on real field geology parameters. We observed two datasets using fixed offset and 2D geometry with different fluid- saturated conditions. Spectral and time-frequency analyses methods are applied to the seismic datasets to describe the response characteristics for gas-, water-, and oil-saturation. The results of physical model dataset processing and analysis indicate that reflection wave tuning and fluid-related dispersion are the main seismic response characteristic mechanisms. Additionally, the gas saturation model can be distinguished from water and oil saturation for Class I AVO utilizing the frequency-dependent abnormal characteristic. The frequency-dependent characteristic analysis of the physical model dataset verified the different spectral response characteristics corresponding to the different fluid-saturated models. Therefore, by careful analysis of real field seismic data, we can obtain the abnormal spectral characteristics induced by the fluid variation and implement fluid detection using seismic data directly.