Lock-up装置在连续梁桥上的减震性能研究

以某客运专线上大跨连续梁桥为实际工程背景,研究了Lock-up装置对结构纵向抗震性能的影响。根据Lock-up装置在地震作用下具有反复锁止的受力特点,采用非线性时程分析方法,分析了锁止速度对结构减震性能的影响。结果表明:对于大跨连续梁桥,Lock-up装置能够充分发挥活动墩的抗震承载能力,有效地提高桥梁结构整体抗震性能。当锁止速度较小时,Lock-up装置可以采用大刚度连杆模拟,并假定其始终处于完全锁定状态。但当锁止速度较高时,应考虑Lock-up装置反复锁止的实际工作特点,否则应用上述计算方法所得的结果偏于不安全。

Lock-up装置的作用机理与分析模型

为探讨Lock-up装置的分析模型,介绍了其构造、阐述了其作用机理,给出了Lock-up装置阻尼力的力学模型并提出了相应的数值模拟方法。基于某铁路桥梁,建立全桥有限空间模型,采用文中提出的模拟方法进行了Lock-up装置的减震性能分析,通过与常用的刚性连杆或主从约束模拟方法的比较,明确了刚性连杆模拟方法的适用条件。结果表明,Lock-up装置的地震作用过程比较复杂,当Lock-up装置能够激发出极大的阻尼力时,文中的模拟方法与常用的刚性连杆或主从约束模拟方法结果非常接近,通常情况按刚性连杆或主从约束模拟方法得到的结果偏大。

粘滞阻尼器和Lock-up装置在连续梁桥抗震中应用

近年来,我国逐渐在一些桥梁结构中使用了可提高结构抗震性能的减隔震装置,如隔震支座、阻尼器(地震响应校正装置)等。对应用较广的粘滞阻尼器和Lock-up装置的工作机理进行了介绍,对其在连续梁桥抗震中的应用进行了研究,通过实际桥例探讨了两种装置对连续梁桥抗震性能改进的有效性,并对其实用的局限性也进行了分析。研究的结果可供桥梁工程设计人员和科研人员参考。

An Interruptable Lock and Unlock Algorithm

Generally, Lock and Unlock statements are primitives that should be wholly imple- mented,i.e.,the test of lock state and the operation of locking must be executed continuously without being interrupted. Different from nmormal lock operations, the lock and Unlock algorithm Presented in this paper can be interrupted anywhere by other processes The value of the algorithm in the implementation of concurrent control and mutually-exclusive operations was elucidated with one application of the algorithm in a heterogeneous datedbase united system.

TOO YOUNG TO LOCK UP?

DR.WANG WENHUA,PROFESSOR OF LAW,VICE DEAN OF THE SCHOOL OF LAW AT BEIJING FOREIGN STUDIES UNIVERSITY,MEMBER OF THE COUNCIL OF CHINESE CRIMINAL LAW SOCIETYIn the last several years,juvenile delinquency has been on the rise,and as it appears more frequently in the public eye,the types of crimes have

Universal precursor seismicity pattern before locked-segment rupture and evolutionary rule for landmark earthquakes

Despite extensive investigations,no precursor patterns for reliably predicting major earthquakes have thus far been identified.Seismogenic locked segments that can accumulate adequate strain energy to cause major earthquakes are highly heterogeneous and low brittle.The progressive cracking of the locked segments with these properties can produce an interesting seismic phenomenon:a landmark earthquake and a sequence of smaller subsequent earthquakes(pre-shocks)always arise prior to another landmark earthquake within a well-defined seismic zone and its current seismic period.Applying a mechanical model,magnitude constraint conditions,and case study data of 62 worldwide seismic zones,we show that two adjacent landmark earthquakes reliably occur at the volume-expansion point and peak-stress point(rupture)of a locked segment;thus,the former is an identified precursor for the latter.Such a precursor seismicity pattern before the locked-segment rupture has definite physical meanings,and it is universal regardless of the focal depth.Because the evolution of landmark earthquakes follows a deterministic rule described by the model,they are predictable.The results of this study lay a firm physical foundation for reliably predicting the occurrence of future landmark earthquakes in a seismic zone and can greatly improve our understanding of earthquake generation mechanism.

Theory of Dynamics In-Phase Locking and Quasi-Period Synchronization in Two Mutually Coupled Multi-Quantum-Well Lasers

Abstract We study dynamics in two mutually coupling multi-quantum-well lasers. We carry out theoretical and numerical analysis of synchronization, anti-synchronization, in-phase locking in the two identical lasers but detuning, in detain. It is proved that the coupling level determines stability of the lasers by analyzing the eigenvalue equation. Critical case of locking is discussed via the phase difference equation. Quasi-period and stable states in the two lasers are investigated via varying the current, detuning and coupling level.

Lock-up装置对大跨连续刚构桥地震响应分析

为研究Lock-up装置对大跨连续刚构桥的地震响应,先介绍了Lock-up装置的基本情况、发展历史、构造及作用机理;接着,以某连续刚构桥为例进行不同情况下的地震响应有限元模拟,在其过渡墩处设置不同的约束,以大跨连续刚构桥墩底及桩顶弯矩和位移为参数进行比较分析。本文计算结果表明,对于大跨连续刚构桥来说,Lock-up装置可以使过渡墩与主墩很好地协同受力,降低地震对主墩的不利影响,得出在地震作用下Lock-up装置对大跨度连续刚构桥非常有效的结论。

Supracutaneous Locking Compression Plate for Grade I &II Compound Fracture Distal Tibia—A Case Series

Background: Supracutaneous plating using a locking compression plate (LCP) as an external fixator in compound periarticular areas is facilitated by the development of anatomical plates. The soft tissue around the distal tibia is easily compromised by trauma and subsequent operative fracture treatment posing a definitive challenge in the distal tibia compound fractures. The purpose of this report is to describe our successful results using the metaphyseal locking compression plate (LCP) as an external fixator in the treatment of Grade I & II compound fractures of distal tibia. Methodology: A total of five (05) patients underwent “supracutaneous plating” of the tibia using a metaphyseal locking compression plate. Average age was 36 years. Regular screw tract dressings were done. Average period of follow-up was 15 months. Results: The plate was in situ for an average of 24 weeks. There were no clinically significant screw site infections. In all five patients the plate was kept in place until there was complete consolidation both clinically and radiologically. At the latest follow-up (average 15 months), all patients were fully weight bearing with a fully healed tibia. All patients were infection-free with well-healed wounds. Conclusion: Routinely, after initial debridement and temporary bony stabilization is provided by external fixation in compound fractures of the distal tibia with significant soft tissue injury. Most external frames for the lower leg are bulky and cumbersome, causing significant problems for the patient. To circumvent these issues, we have successfully used an anatomically-contoured supracutaneous metaphyseal locking compression plate as external fixator in a series of five patients for grade I & II compound fracture of the distal tibia.

Is Distal Femur Locking Plate a Superior Implant in Distal Femur Fracture?

In spite of advances in techniques and improvements in surgical implants, confusion still prevails regarding use of specific implants in distal femur fracture. Fractures in the distal femur have posed considerable therapeutic challenges throughout the history of fracture treatment. Most of these surgical failures were due to inadequate fixation of the fracture fragments. The Aim of the study is to determine whether distal femur locking plates are superior implants than dynamic condylar screw and distal femur nail. A prospective and observational study was done in Department of Orthopaedics and Traumatology, Sri Ramachandra Medical Collage, Chennai between Jan. 2011 and Jan. 2015. Patients with distal femoral fractures, admitted into the hospital, were treated using various modes of internal fixation and followed up over a period of six months to one year and their functional outcome was evaluated. The functional and radiological assessment of patients during follow-up was done using Neer’s criteria. The use of any one of the implant, i.e. distal femur locking plates, dynamic condylar screw or distal femur nailing for internal fixation, depends on the type of fracture and the pre operative planning and intra operate decision of the surgeon. In our study, 38% of fractures treated by Dynamic condylar screw, 72% of fractures treated by distal femur locking plate and 42% of fractures treated by Distal femur supracondylar nail had excellent/satisfactory results. Locking plates had better outcome in both extra-articular and intra-articular group. They also had better outcome in both younger and older age groups.

动力吸振器在CVT车型LockUp方向盘振动控制中的应用

在介绍CVT车型LockUp工作原理和动力吸振器工作原理的基础上,针对某款车型的Lock Up方向盘振动问题,分别对Lock Up传递路径和方向盘共振特性进行了分析。结果表明,驱动轴和悬置入力是产生此问题的主要原因。但是考虑到驱动轴和悬置系统改动难度大的问题,提出了采用动力吸振器进行方向盘振动控制的方法。通过优化动力吸振器参数,成功使得方向盘的振动减小到了可接受的范围。

Neural Network Prediction of Disruptions Caused by Locked Modes on J-TEXT Tokamak

Prediction of disruptions caused by locked modes using the Back-Propagation （BP） neural network is completed on J-TEXT tokamak. The network, which is based on the BP neural network, uses Mirnov coils and locked mode coils signals as input data, and outputs a signal including information of prediction of locked mode. The rate of successful prediction of locked modes is more than 90%. For intrinsic locked mode disruptions, the network can give a prewarning signal about 1 ms ahead of the locking-time. For the disruption caused by resonant magnetic perturbation （RMPs） locked modes, the network can give a prewarning signal about 10 ms ahead of the locking-time.

Phase—Locking Dynamics in Coupled Circle—Map Lattices

The phase-locking dynamics in 1D and 2D lattices of non-identical coupled circle maps is explored. Aglobal phase locking can be attained via a cascade of clustering processes with the increase of the coupling strength.Collective spatiotemporal dynamics is observed when a global phase locking is reached. Crisis-induced desynchronizationis found, and its consequent spatiotemporal chaos is studied.

Frequencies of Lock Gate Structure Coupled with Reservoir Fluid

This study determines the natural frequencies of the lock gate structure,considering the coupled effect of reservoir fluid on one side using the finite element method(FEM).The gate is assumed to be a uniformly thick plate,and its material is isotropic,homogeneous,and elastic.The reservoir fluid is assumed to be inviscid and incompressible in an irrotational flow field.The length of the reservoir domain is truncated using the far boundary condition by adopting the Fourier series expansion theory.Two different assumptions on the free surface,i.e.,undisturbed and linearized,are considered in the fluid domain analysis.The computer code is written based on the developed finite element formulations.The natural frequencies of the lock gate are computed when interacting with and without reservoir fluid.Several numerical problems are studied considering the effects of boundary conditions,aspect ratios,and varying dimensions of the gate and the fluid domain.The frequencies of gate reduce significantly due to the presence of fluid.The frequencies increase when the fluid extends to either side of the gate.The frequencies reduce when the depth of the fluid domain above the top edge of the gate increases.The frequencies drop considerably when the free surface condition is taken into account.The results of frequencies of lock gate structure may be useful to the designer if it is experienced in natural catastrophes.

An injection-locking diode laser at 671 nm with a wide tuning range up to 6 GHz

We present a compact injection-locking diode laser module to generate 671 nm laser light with a high output power up to 150 m W.The module adopts a master-slave injection-locking scheme,and the injection-locking state is monitored using the transmission spectrum from a Fabry-Perot interferometer.Beat frequency spectrum measurement shows that the injection-locked slave laser has no other frequency components within the 150-MHz detection bandwidth.It is found that without additional electronic feedback,the slave laser can follow the master laser over a wide range of 6 GHz.All the elements of the module are commercially available,which favors fast construction of a complete 671-nm laser system for the preparation of cold^(6)Li atoms with only one research-grade diode laser as the seeding source.

＂Some Reflections upon the True Grounds ofMorality＂ Catharine Trotter in Defence of John Locke

Although excluded from the standard account of the history of philosophy, Catharine Trotter Cockbum （1679-1749）avoided the 17th-century bias against female intellectual skills and was an active contributor to the early modemphilosophical discourse. In her Defence of Mr Locke＇s Essay （1702）, she defended Locke from several criticisms byThomas Burnet （1635-1715）. By analysing three of Bumet＇s main arguments, such as the theory of naturalconscience, his anti-voluntarism, and his belief in the immateriality of the soul, Trotter showed that he oftenmisinterpreted John Locke＇s principles, especially those concerning his moral epistemology.

Lock-up装置在连续梁桥中应用的优化研究

以某5跨连续梁桥为工程背景,对Lock-up装置的工作性能和机理进行了分析。采用非线性时程分析方法,对地震中Lock-up装置锁止速度和Lock-up装置的位置对桥梁减震的影响进行了分析,得到了Lock-up的最优锁止速度和该桥的最优减震方案。结果表明:对于多跨连续梁桥,Lock-up装置可以很好地提高桥梁的整体抗震性能;从经济和减震效果看并不是越多的Lock-up装置越好。

On the generation of high-quality Nyquist pulses in mode-locked fiber lasers

Nyquist pulses have wide applications in many areas,from electronics to optics.Mode-locked lasers are ideal platforms to generate such pulses.However,how to generate high-quality Nyquist pulses in mode-locked lasers remains elusive.We address this problem by managing different physical effects in mode-locked fiber lasers through extensive numerical simulations.We find that net dispersion,linear loss,gain and filter shaping can affect the quality of Nyquist pulses significantly.We also demonstrate that Nyquist pulses experience similariton shaping due to the nonlinear attractor effect in the gain medium.Our work may contribute to the design of Nyquist pulse sources and enrich the understanding of pulse shaping dynamics in mode-locked lasers.

Dissipative soliton resonance within different dispersion regimes in a single mode-locked laser

Dissipative soliton resonance(DSR) was previously studied in separated mode-locked fiber lasers within different dispersion regimes including anomalous, near-zero and normal dispersion. Here we propose a method to study DSR in a single mode-locked laser in these different dispersion regimes. This is achieved by virtue of a waveshaper which can control the laser dispersion readily using software, avoiding the usual tedious cutback method. We find that dispersion has a negligible effect on DSR since the pulse duration keeps constant while dispersion is varied. Moreover, we examine the dynamics of DSR on the parameters of the SA including modulation depth and saturation power, and find that the pulse duration can be changed in a large range when the saturation power is decreased. Our numerical simulations could be important to guide relative experimental studies.

Dynamic gain driven mode-locking in GHz fiber laser

Ultrafast lasers have become powerful tools in various fields,and increasing their fundamental repetition rates to the gigahertz(GHz)level holds great potential for frontier scientific and industrial applications.Among various schemes,passive mode-locking in ultrashort-cavity fiber laser is promising for generating GHz ultrashort pulses(typically solitons),for its simplicity and robustness.However,its pulse energy is far lower than the critical value of the existing theory,leading to open questions on the mode-locking mechanism of GHz fiber lasers.Here,we study the passive mode-locking in GHz fiber lasers by exploring dynamic gain depletion and recovery(GDR)effect,and establish a theoretical model for comprehensively understanding its low-threshold mode-locking mechanism with multi-GHz fundamental repetition rates.Specifically,the GDR effect yields an effective interaction force and thereby binds multi-GHz solitons to form a counterpart of soliton crystals.It is found that the resulting collective behavior of the solitons effectively reduces the saturation energy of the gain fiber and permits orders of magnitude lower pulse energy for continuous-wave mode-locking(CWML).A new concept of quasi-single soliton defined in a strongly correlated length is also proposed to gain insight into the dynamics of soliton assembling,which enables the crossover from the present mode-locking theory to the existing one.Specifically,two distinguishing dynamics of Q-switched mode-locking that respectively exhibit rectangular-and Gaussian-shape envelopes are theoretically indicated and experimentally verified in the mode-locked GHz fiber laser through the measurements using both the standard real-time oscilloscope and emerging time-lens magnification.Based on the proposed criterion of CWML,we finally implement a GDR-mediated mode-locked fiber laser with an unprecedentedly high fundamental repetition rate of up to 21 GHz and a signal-tonoise ratio of 85.9 dB.