Investigation into rail corrugation in high-speed railway tracks from the viewpoint of the frictional self-excited vibration of a wheel–rail system

A finite element vibration model of a multiple wheel-rail system which consists of four wheels, one rail, and a series of sleepers is established to address the problem of rail corrugation in high-speed tracks. In the model, the creep forces between the wheels and rail are considered to be saturated and equal to the normal contact forces times the friction coefficient. The oscillation of the rail is coupled with that of wheels in the action of the saturated creep forces. When the coupling is strong, self- excited oscillation of the wheel-rail system occurs. The self-excited vibration propensity of the model is analyzed using the complex eigenvalue method. Results show that there are strong propensities of unstable self-excited vibrations whose frequencies are less than 1,200 Hz under some conditions. Preventing wheels from slipping on rails is an effective method for suppressing rail corrugation in high-speed tracks.

植物乳杆菌WU146-磷酸-β-葡萄糖苷酶的基因克隆、蛋白表达及生物信息学分析

植物乳杆菌是一类兼性异养,兼性厌氧的同型发酵乳酸菌,其在改善食品风味和发酵特性等方面发挥着重要作用,而这种功能特征与其具有糖苷酶活性密切相关。为了挖掘植物乳杆菌糖苷酶的应用价值,以植物乳杆菌WU14为研究对象,利用聚合酶链式反应(PCR)技术成功克隆了8个WU14的糖苷水解酶,生物信息学分析表明均为糖苷水解酶1家族(GH1)的6-磷酸-β-葡萄糖苷酶基因。鉴于植物乳杆菌中该类糖苷酶鲜有报道,采用原核异源表达展开研究。序列分析表明8个酶蛋白氨基酸序列具有GH1家族的6-磷酸-β-葡萄糖苷酶典型的2个保守催化位点,序列一致性在32%~74%之间。经SDS-PAGE,8个蛋白均在大肠杆菌中表达,其中BglAW14、BglCW14、BglFW14为部分可溶性表达,其余为蛋白表达,形成包涵体。生物信息学分析显示:8个基因的编码蛋白都无信号肽和跨膜结构,疏水性较强。由亚细胞定位预测可知,除BglEW14主要存在于分泌结构内和BglHW14主要存在于细胞膜外,其余6个基因都存于细胞质内。对8个6-磷酸-β-葡萄糖苷酶基因的克隆表达及生物学序列分析,为进一步探究植物乳杆菌来源的6-磷酸-β-葡萄糖苷酶的分子机理研究奠定了基础。

Monitoring subsidence rates along road network by persistent scatterer SAR interferometry with high-resolution TerraSAR-X imagery

Ground subsidence is one of the key factors damaging transportation facilities, e.g., road networks consisting of highways and railways. In this paper, we propose to apply the persistent scatterer synthetic aperture radar interferometry （PS-InSAR） approach that uses high- resolution TerraSAR-X （TSX） imagery to extract the regional scale subsidence rates （i.e., average annual sub- sidence in mm/year） along road networks. The primary procedures involve interferometric pair selection, interfer- ogram generation, persistent scatterer （PS） detection, PS networking, phase parameterization, and subsidence rate estimation. The Xiqing District in southwest Tianjin （China） is selected as the study area. This district contains one railway line and several highway lines. A total of 15 TSX images covering this area between April 2009 and June 2010 are utilized to obtain the subsidence rates by using the PS-InSAR （PSI） approach. The subsidence rates derived from PSI range from -68.7 to -1.3 mm/year. These findings show a significantly uneven subsidence pattern along the road network. Comparison between the PSI-derived subsidence rates and the leveling data obtained along the highways shows that the mean and standard deviation （SD） of the discrepancies between the two types of subsidence rates are 0.1 and 4-3.2 mm/year, respectively. The results indicate that the high-resolution TSX PSI is capable of providing comprehensive and detailed subsidence information regarding road networks with millimeter-level accuracy. Further inspections under geo- logical conditions and land-use categories in the study area indicate that the observed subsidence is highly related to aquifer compression due to groundwater pumping. Therefore, measures should be taken to mitigate groundwater extraction for the study area.

Overview and outlook on railway track stiffness measurement

Stiffness is one of the basic performance parameters for railway track. The efficient and accurate stiffness measurement has been considered as the foundation for further development of railway engineering, and therefore has great theoretical and practical significance. Based on a summary of the connotation and measurement of track stiffness, the state of the art of measurement methods for track stiffness was analyzed systematically. The standstill measurement of track stiffness can be performed with the traditional jack-loading method, impact hammer method, FWD （falling weight deflectometer） method, and track loading vehicle method. Although these methods can be adopted in stiffness measurement for a section of railway track, they are not desirable owning to small range and low efficiency. In the recent 20 years, researchers have proposed many methods like unbalancedloading laser displacement method, deflection basin deformation rate method, and eccentricity excitation method to continuously measure track stiffness; however, these methods have drawbacks like poor accuracy, low speed, and insufficient data analysis. In this work, the merits and demerits of these methods were summarized, and optimization suggestions were presented. Based on the wave transmission mechanism and principle of vibration energy harvesting, an overall conception on continuous measurement of stiffness and long-term stiffness monitoring for special sections was proposed.

Improvement of railway performance： a study of Swedish railway infrastructure

The volume of rail traffic was increased by 5 % from 2006 to 2010, in Sweden, due to increased goods and passenger traffic. This increased traffic, in turn, has led to a more rapid degradation of the railway track, which has resulted in higher maintenance costs. In general, degradation affects comfort, safety, and track quality, as well as, reliability, availability, speed, and overall railway performance. This case study investigated the needs of railway stakeholders responsible for analysing the track state and what information is necessary to make good maintenance decisions. The goal is to improve the railway track per- formance by ensuring increased availability, reliability, and safety, along with a decreased maintenance cost. Inter- views of eight experts were undertaken to learn of general areas in need of improvement, and a quantitative analysis of condition monitoring data was conducted to find more specific information. The results show that by implement- ing a long-term maintenance strategy and by conducting preventive maintenance actions maintenance costs would be reduced. In addition to that, problems with measured data, missing data, and incorrect location data resulted in increased and unnecessary maintenance tasks. The conclusions show that proactive solutions are needed to reach the desired goals of improved safety, improved availability, and improved reliability. This also includes thedevelopment of a visualisation tool and a life cycle cost model for maintenance strategies.

A new triterpene saponin from Panax japonicus C.A.Meyer var major(Burk.) C.Y.Wu et K.M.Feng

One new Iriterpene saponin was isolated from Panaxjaponicus C. A. Meyer var major （Burk.） C. Y. Wu et K. M. Feng, and established as oleanolic acid 3-O-[β-D-glucopyranosyl-（1 →2）-β-D-glucuronopyranosyl-6＇-O-n-butyl ester] which showed mod- erate antitumor activities against the A2780 cells and OVCAR-3 cells. Its structure was established by means of spectral data, particularly NMR, including HSQC and HMBC techniques.

On resolution to Wu's conjecture on Cauchy function's exterior singularities

This is a series of studies on Wu＇s conjecture and on its resolution to be presented herein. Both are devoted to expound all the comprehensive properties of Cauchy＇s function f（z） （z = x ＋ iy） and its integral J[f（z）]≡（2πi）-∮cf（t）（t-z）-1dt taken along the unit circle as contour C,inside which（the open domain D＋） f（z） is regular but has singularities distributed in open domain Doutside C. Resolution is given to the inverse problem that the singularities of f（z） can be determined in analytical form in terms of the values f（t） of f（z） numerically prescribed on C（｜t｜ = 1） ,as so enunciated by Wu＇s conjecture. The case of a single singularity is solved using complex algebra and analysis to acquire the solution structure for a standard reference. Multiple singularities are resolved by reducing them to a single one by elimination in principle,for which purpose a general asymptotic method is developed here for resolution to the conjecture by induction,and essential singularities are treated with employing the generalized Hilbert transforms. These new methods are applicable to relevant problems in mathematics,engineering and technology in analogy with resolving the inverse problem presented here.

Question of Parity Non-conservation in Weak Interactions

In order to reasonably explain the phenomenon of cell bioelectricity,we proposed the conservation law of cell membrane area,established the ion inequality equation,and therefore paid attention to the mystery of“θ-τ”.We researched and analyzed the“θ-τ”mystery,discussed the parity non-conservation in weak interactions,suggested possible experiments to test the parity non-conservation in weak interactions,and gave our research and analysis conclusions:The parity non-conservation in weak interactions,is still a“conjecture”;The experimental scheme suggested in the papers by C.N.Yang et al.cannot determine whether the weak interaction can separate left and right,and it is impossible to directly answer whetherθandτin the“θ-τ”mystery are the same particle;The Co60βdecay experiment such as C.S.Wu is a pseudo-mirror experiment,whether the experimental result violates parity conservation is only based on the assumption of C.N.Yang et al.In fact,experiments such as polarized Co60 did not overturn the so-called“law of parity conservation”.The mirror image principle does not have any physical meaning,does not correspond to any physical conservation quantity,and cannot be destroyed by any physical experiment.In the process of turning“mirror symmetry”and“mirror asymmetry”into so-called physical“common sense”and scientific“facts”respectively,the methods of transformation are“stealing concepts”and“circular argumentation”.The“θ-τ”mystery is a“man-made”mystery.θandτare two different particles,which may be the result of the same precursor particle being divided into two.The work of C.N.Yang,T.D.Lee,C.S.Wu et al.has brought quantum physicists from the“small black room”to the“bigger black room”or“smaller black room”.The right and wise choice is to go back through the door that came in.With the development of science today,it is time for some contents to reform from the bottom.

WU27Y—25双头弯管机、JH21—200型压力机

最近研制成功WU27Y—25双头弯管机,该机为全液压传动,弯管的夹紧、弯曲、退回全部程序在7～10s内自动完成,生产效率高,适用范围广,特别适用于钢家具、汽车、轮船、飞机等制造业中的座椅、框架状钢管制品的弯管工序。

Railroad capacity tools and methodologies in the U.S. and Europe

A growing demand for passenger and freight transportation, combined with limited capital to expand the United States （U.S.） rail infrastructure, is creating pressure for a more efficient use of the current line capacity. This is further exacerbated by the fact that most passenger rail services operate on corridors that are shared with freight traffic. A capacity analysis is one alternative to address the situation and there are various approaches, tools, and methodologies available for application. As the U.S. continues to develop higher speed passenger services with similar characteristics to those in European shared-use lines, understanding the common methods and tools used on both continents grows in relevance. There has not as yet been a detailed investigation as to how each continent approaches capacity analysis, and whether any benefits could be gained from cross-pollination. This paper utilizes more than 50 past capacity studies from the U.S. and Europe to describe the different railroad capacity defini- tions and approaches, and then categorizes them, based on each approach. The capacity methods are commonly di- vided into analytical and simulation methods, but this paper also introduces a third, ＂combined simulation- analytical＂ category. The paper concludes that Europeanrail studies are more unified in terms of capacity, concepts, and techniques, while the U.S. studies represent a greater variation in methods, tools, and objectives. The majority of studies on both continents use either simulation or a combined simulation-analytical approach. However, due to the significant differences between operating philosophy and network characteristics of these two rail systems, European studies tend to use timetable-based simulation tools as opposed to the non-timetable-based tools commonly used in the U.S. rail networks. It was also found that validation of studies against actual operations was not typically completed or was limited to comparisons with a base model.

Were the Miao Kings ＂Prophets of Renewal＂？ The Case of the 1795-1797 Hunan Miao Revolt

This essay considers the concept of ＂prophets of renewal＂ introduced by James Scott in The Art of Not Being Governed.. An Anarchist History of Upland Southeast Asia （2009）, as seen in the context of the 1795-97 Miao revolt along China＇s Hunan-Guizhou border. The appearance ofa ＂Miao King＂ and four ＂Wu kings＂ centering anti-Qing resistance in an intractable highland--utilizing native legends, spirit possession, investment of officials, and multi-ethnic recruitment--suggests a case of＂Zomia＂ （the vast Southeast Asian Massif） prophets in action, as Scott himself suggests. Closer examination, however, reveals a more complex and uncertain picture, characterized by division between rival lords and an overall dearth of institutional, ideological, or cosmological elaboration, all further obscured by a paucity of historical sources. The Miao kings might be seen as prophets of renewal in a general sense, but the fit is inexact. There is still value, however, in considering Scott＇s model in the study of this event. It enables a sharper conceptualization of the agency of the Miao people, while offering a case for comparison with analogous instances of religiously-based native resistance on other Qing frontiers.