摘要：This paper presents an investigation on the effect of probe support on the flow field of an axial *** experiment is carried out in a large-scale low-speed research compressor.A cylindrical probe support intruding to 50% blade span was installed at 50% chord upstream from the rotor leading *** region from 5° to 32° off the probe support in the direction of rotation at the rotor outlet was measured with a 5-hole probe and a high-response total pressure *** experiment is performed at both near-design and near-stall *** measuring results of 5-hole probe and high-response total pressure probe indicate that the probe blockage effect is different at different blade *** wake of the probe support weakens the leakage vortex intensity at the tip region,leading to greater total pressure *** near-design condition,the presence of probe support has a negative effect on the region from 75% to 92% span,while improves the flow field below 75% *** near stall condition,the probe support has a negative effect on the region from 70% to 90% span,and almost has no influence on the flow field below 70% span.

摘要：This paper presents the investigation of the effects of suction side squealer tip on the performance of an axial compressor. The experiment is carded out in a single-stage large-scale low-speed compressor. The investigated tip geometries include fiat tip as the baseline and suction side squealer tip. The tip clearance of the baseline is 0.5% of the blade span. The static pressure rise characteristic curves of both the rotor and the stage are measured. The flow field at the exit of the rotor is measured by a 5-hole probe under design and off-design conditions. The static pressure on the endwall of the rotor passage is also obtained. The results show that the pressure rise characteristic curves obtained by measuring the pressure on the end wall are almost unchanged by using the suction side squealer tip. The measuring results of the 5-hole probe show the static pressure and the total pressure in tip region is slightly greater than that of the flat tip at the design condition at the exit of the rotor. It also leads to greater averaged static pressure rise and total pressure. At the near stall condition, the averaged static pressure and total pressure is lower than the baseline which is related to the redistribution of the blade load caused by the suction side squealer tip.

摘要：Sarcaglarols A-D(1-4),two pairs of lindenane-monoterpene heterodimers fused by a 1,2-dioxane moiety,were discovered and isolated from the leaves of Sarcandra glabra guided by MS/MS molecular networking-based *** planar structures,absolute configurations of basic skeleton and flexible polyhydric side chain were established by analysis of HRESIMS,NMR spectroscopic data,ECD spectrum,and the X-ray diffraction study of isopropylidene *** intermolecular[2+2+2]cycloaddition may play a key role in the biosynthesis pathway of the 1,2-dioxane moiety fused lindenane-monoterpene heterodimer skeleton,which can be recognized as the biogenetic precursors of our previous reported lindenane-normonoterpene *** addition,compounds 1,3 and 4 exhibited moderate inhibitory effects of lipid accumulation in free fatty acid-exposed L02 cells.

摘要：In order to monitor deformation of high temperature components for a long time,a sensing device integrating a bridge-shaped mechanical displacement amplifier has been *** sensing device has higher resolution and accuracy than conventional ***,the relation between the magnification ratio and the structure size of the displacement amplifier is a bottleneck of sensing device *** this,the magnification ratio of a mechanical displacement amplifier is analytically derived based on its geometry *** prototypes of the displacement amplifier made in propathene are manufactured,and an experimental system is set up to validate the accuracy of the established magnification ratio *** magnification ratios and experimental magnification ratios are compared and agree well,which verifies that the proposed equation is *** analytical equation provides an effective design method for bridge-shaped mechanical displacement amplifiers with an expected magnification ratio.

摘要：Atmospheric oxygen （02） is the most crucial element on earth for the aerobic organisms that depend on it to release energy from carbon-based macromolecules. This is the first study to systematically analyze the global O2 budget and its changes over the past 100 years. It is found that anthropogenic fossil fuel combustion is the largest contributor to the current O2 deficit, which consumed 2.0 Gt/a in 1900 and has increased to 38.2 Gt/a by 2015. Under the Representative Concentration Pathways （RCPs） RCP8,5 scenario, approximately 100Gt （gigatonnes） of O2 would be removed from the atmosphere per year until 2100, and the O2 concentration will decrease from its current level of 20.946% to 20.825%. Human activities have caused irreversible decline of atmospheric O2. It is time to take actions to promote O2 production and reduce O2 consumption.

摘要：The design synthesis is the key issue in the mechanical conceptual design to generate the design candidates that meet the design *** paper devotes to propose a novel and computable synthesis approach of mechanisms based on graph theory and polynomial *** graph framework of the synthesis approach is built firstly,and it involves:(1)the kinematic function units extracted from mechanisms;(2)the kinematic link graph that transforms the synthesis problem from mechanical domain into graph domain;(3)two graph representations,i.e.,walk representation and path representation,of design candidates;(4)a weighted matrix theorem that transforms the synthesis process into polynomial ***,the formulas and algorithm to the polynomial operation are *** on them,the computational flowchart to the synthesis approach is summarized.A design example is used to validate and illustrate the synthesis approach in *** proposed synthesis approach is not only supportive to enumerate the design candidates to the conceptual design of a mechanical system exhaustively and automatically,but also helpful to make that enumeration process computable.

摘要：We review recent research activities on structural reliability analysis,reliability-based design optimization(RBDO) and applications in complex engineering structural *** novel uncertainty propagation methods and reliability models,which are the basis of the reliability assessment,are *** addition,recent developments on reliability evaluation and sensitivity analysis are highlighted as well as implementation strategies for RBDO.

摘要：Hyperthermia has been considered as a promising healing treatment in bone regeneration. We designed a tissue engineering hydrogel based on magnetic nanoparticles to explore the characteristics of hyperthermia for osteogenic regeneration. This nanocomposite hydrogel was successfully fabricated by incorporating magnetic Fe_3O_4 nanoparticles into chitosan/polyethylene glycol(PEG) hydrogel, which showed excellent biocompatibility and were able to easily achieve increasing temperatures under an alternative magnetic field(AMF). With uniformly dispersed nanoparticles, the composite hydrogel resulted in high viability of mesenchymal stem cells(MSCs), and the elevated temperature contributed to the highest osteogenic differentiation ability compared with direct heat treatment applied under equal temperatures. Therefore, the nanoheat stimulation method using the magnetic nanocomposite hydrogel under an AMF may be considered as an alternative candidate in bone tissue engineering regenerative applications.

摘要：未来活动通讯系统瞄准提供很高的数据传播率，甚至在象高速度的车轮轨道火车，磁悬浮火车火车，高速公路车辆，飞机，指导导弹或太空船那样的高活动性的情形。一个特别地重要的商业应用程序是对高速度的宽带的强壮、增加的世界范围的要求无线通讯(多达 574.8 ? km/h 测试速度或 380 ? km/h 广告速度)为象为旅客的机载的娱乐服务那样的应用程序在铁路，提供的数据，声音和录像满足，火车控制，训练派遣，火车传感器地位处理和监视。在如此的高活动性的情形，有很多通讯挑战，包括快移交，更新的地点，当模特儿的高速度的隧道，评价和均等， anti-Doppler 传播技术，快力量控制，和奉献网络建筑学。因为在很高速度的情形的信号传播将不可避免地经历 s ……

摘要：Power System Stabilizer (PSS) was proposed during 1960s to solve the low frequency oscillation problem raised by the wide application of the high-gain fast-response exciters. The fundamentals of PSS design lie in the angle compensation to increase the damping torque, which, since then, has become an important principle in designing the various power system dampers, such as SVC, TCSC, UPFC. Although many papers have been dedicated to the application of this principle, it is interesting to note that in the real industry applications PSS parameters have to be carefully tuned on site in spite of its mature design theory. So does the classical PSS design theory really meet the PSS design demand? By combining the frequency domain and the time domain analysis, this paper reinvestigates the basic idea behind the classical PSS design theory. The paper clarifies the con-cepts of the synchronous torque as well as the damping torque and proves that the classical PSS design principles based on these concepts are not theoretically sound. Then the paper discusses the Linear Optimal Controller Design method and ana-lyzes its relations with the conventional PID design. By doing so the paper reveals the real mechanism of the PSS and proposes to use more systematic and advanced control tools to enhance the controller performance.