Fiber Fabry-Perot Sensor and Its Application for Monitoring Bridge Strain

The strain is an important parameter that reflects the bridge health status, the fiber Fabry-Perot sensor is embedded in the concrete structure as the intelligent sensing element for the bridge strain. The strain measuring system is made up of the fiber Fabry-Perot sensor,light switch,fiber strain gauge and the comput- er; it can be used to monitor automatically the bridge strain. At present,the system has been installed in the Dafosi Bridge over the Yangtze River in Chongqing. The monitoring data show that the fiber Fabry-Perot sensor has good stability and reliability; it can be used to monitor the bridge strain for a long time.     

Fatigue life finite element analysis of output gear pair of wind turbine speed-increase gearbox

Cracking monitoring provides an important way to evaluate structural safety. Cracking monitoring method based on distributed optical fiber sensor can effectively avoid undetected phenomenon existed in point-wise test method, and it can run automatically. A theoretical model of cracking monitoring based on obliquely intersected fibers and Brillouin Optical Time Domain Analysis (BOTDA) is introduced, and the numerical equation among fiber strain, crack width and crack angle is established by the calibration experiment. The experiments are also carried out to study the performance of different kinds of cracking sensors with different gauge length and pretension. The quantitative relationship between optical fiber measured strain and crack (including width and angle) is established for the 300 millimeter crack sensor. The cracking simulation test proved that this new method can effectively record the width and the angle of cracks during the whole cracking process.     

Development of an Optical Fiber Spectrograph for Detecting Living Liquid

This paper introduces a fiber optical spectrograph which can directly measure the liquid of the living body. Based on the property of fiber optical and capillary, the authors design a special optical fiber probe which can directly insert the living body to sample the liquid and plunge the liquid into the optical path. That is ,the sample liquid can be directly tested without any pre processing. So this operation simplified the detecting process and perform measurement in situ. In order to improve the sentivity of the probe, the optical fibers in the probe are distributed in layers so as to increasing the optical length of the living liquid. On the other hand, the computer control the stepward motor to rotate through the pulses emitting from the parallel port of the computer so as to drive the quart prism rotating. The optical signal is accepted by the photomultipler and sampled by the computer. This spectrograph can display in time the spectrum of the living liquid on the screen. Through analysing the spectrum of the living liquid, many living parameters can be detected.     

The Optical Signal Processing of Distributed Fiber Optical Force Sensors

For the distributed fiber optical sen sor based on the principle of mede-coupling of polarization-maintaining fiber and the theory of partial coherence of quasi-monochromatic light,it is of great importance to process the weak optical signal from the sensing fiber.The characteristics of the optical slgnal was analyzed and suggestions were given for medified Mach-Zehnder interfer-ometer,which in cludes an acoustooptical medulator and a polarized-beam splitter to realize the het-erodyne in terferen ce. The method not only eliminates the influences of light source fluctuation and background light,but decreases the loss of the signal ptocessing,and improves S/N ratio.The experi-ment results coincide well with the analysis.     

THE ALGORITHM OF COMPUTEROPTICAL-FIBERDIFFERENTIAL PROTECTION to show POSITIVE SEQUENCE FAULTED COMPONENT CURRENTS

Because of unsatisfied relaying protection of short transmission lines, a new differential protection system consisting of microcomputer and optical fiber channel has been presented in this paper. According to this system, a new algorithm including a differential criterion used for the positive sequence currents caused by faults and a difference-half cycle Fourier filtering method has been set up.     

Mechanical Properties and Durability of Extruded Fiber Reinforced Cement Mortar Board and Its Composite Beam

The effect of water to cement ratio, fiber types and content, cement types on the bending performance of the extruded fiber reinforced cementitious board were studied. And it was found that polyvinyl alcohol (PVA) fibers can significantly improve the ductility of the board compared with polypropylene (PP) fibers. As PVA fiber content achieved 1.7%, the strain hardening and multiple cracking were occurred on the extruded board, while strain softening were shown on PP fiber reinforced cement board. The difference between the two kinds of board was from the differences of the mechanical properties of the two fibers. In addition, taking the fiber reinforced extruded board as base, the ultimate bending strength, as well as and the corresponded deflection and the resistant to chloride iron penetrating, was improved for a composite beam with fiber board and concrete compared with those of traditional concrete beam.     

Strain rate effects on dynamic behavior of reinforcement concrete columns with various reinforcement ratio

The mechnical characteristics of concrete is sensitive to the strain rate and it is crucial to consider the effect of load rates on the behavior of reinforced concrete (RC) structures subjected to dynamic loads such as severe earthquakes. In this study, numerical simulations on the dynamic behavior of typical RC column specimens under dynamic loadings with different load rates were performed. Concrete constitutive model considering the strain rate effects proposed by the CEB code was employed with a fiber model to characterize the nonlinear strain rate dependent behavior of RC columns. The developed dynamic fiber element model was validated by comparing the simulated results of four RC column specimens with the fast loading test results. Results show that the developed fiber element model can predict the behavior of RC columns with acceptable accuracy. After valiating the proposed fiber elemen model considering the strain rate effect, the load carrying capacity of different RC columns with various longitudinal reinforcement ratios and volumetric stirrup ratios were simulated. Results show that the trends of the influences of longitudinal reinforcement ratios and volumetric stirrup ratios on the load carrying capacity of the RC columns under dynamic loadings are different.     

Development of Embedded ECG Monitor Based on Linux

Presently, ECG monitor encounters the trend of miniaturizing, intelligentizing and networking. Short distance and limited channels are shortcomings of the existed telemetric ECG (Electrocardiograph) monitoring system, while the existed remote monitoring system has the disadvantages of high cost and low Data Transfer Rate. Furthermore, neither of these two systems can implement real-time monitoring on the spot. So, an embedded ECG Monitor based on Linux, which successfully solves these problems, is introduced. With embedded system technique, this embedded monitor, which can not only realize real-time monitoring on the spot, but also analyse the ECG data, has the advantages of low cost, small volume, light weight, low power, high stability, powerful networking function and so on. And by communicating through Internet, which has the features of low cost, high data transfer rate and good expandability, it can also send ECG data to monitoring center in order to achieve long-term monitoring. The development of this monitor provides a new solution for medical instruments' implementation and networking, and is of certain reference value.     

New Development of Transmission Researches about Optical Solitons in Optical Fiber Telecommunication Systems

This paper prieseuts comprehensively new development of transmission researches about the optical solitons in optical fiber tele communication systems abroad,including:1.N soliton interaction in optical fiber;2.pulse propagation in the fiber;3.the femtosecond soliton soliton interaction in dispersion shifted fiber;4.strongly coupled nonlinear parametric solitary waves;5.higher order effects in bandwidth limited soliton propagation in optical fibers;6.suppression of noise accumulation in band width limited soliton transmission by means of nonlinear loop mirrors.     

Experimental Analysis on the Frost Resistance of Steel Fiber Reinforced Concrete

The frost resistance of steel fiber reinforced concrete (SFRC) was studied based on the fast freeze thaw tests in water and in a 3.5% sodium chloride solution, with different mass fraction of steel fiber in concrete at 0%, 0.5%, 1.0%, 1.5% and 2.0%, respectively. The effects of the number of freeze thaw cycles and the volume fraction of steel fiber on the mass lose rate, the splitting strength loss rate and the dynamic modulus of elasticity of SFRC were analyzed. The reinforcement mechanism of the steel fiber under the action of freeze and thaw was also discussed. Moreover, mercury intrusion method and SEM analysis were carried out to study the pore size distribution features and the performance of microstructure on the impact of frost resistance of SFRC. The results show that adding an appropriate amount of steel fiber into concrete can reduce the pore porosity and improve the compactness of concrete. Furthermore, the presence of steel fiber proves to shrink the porosity and improve evidently the frost resistance of concrete. It is also shown that the steel fiber content has a great influence on the frost resisting property of SFRC. The best performance of SFRC can be achieved when the volume fraction of steel fiber is 1.5%.     

预应力CFRP布及预紧螺栓加固RC梁试验研究

为提高碳纤维布加固RC结构的效果及其可靠性,提出了预应力碳纤维布与预紧螺栓联合加固技术。结合在役RC梁的损伤特点及目前的RC梁加固方法,分别采用不同的碳纤维布加固技术对完整梁和破坏梁的抗弯性能进行了对比试验研究。针对目前碳纤维布张拉设备的缺陷,研发了便于现场应用的新型碳纤维布布张拉设备,分析了预应力大小对加固效果的影响。结果表明,预应力碳纤维布及预紧螺栓联合加固技术是一种更可靠的桥梁加固方法,不仅能够提高RC梁正截面的抗弯承载能力及正常使用阶段的截面刚度,而且螺栓预紧锚固碳纤维布能够很好地抑制其在混凝土表面的剥离,提高碳纤维布与混凝土表面之间粘结强度,对碳纤维布施加预应力能够充分发挥其高强性能,有效抑制混凝土裂缝开裂和开展。     

棉纤维品质长度的图像测量

提出了一种新的棉纤维品质长度的检测方法。该方法主要通过使用CCD、计算机、高亮度光源构成的精准测量系统而实现,它能够准确测量Hertel曲线上任意一点的纤维累积根数。基于随机分布理论,建立了纤维长度分布的数学模型,实现了对主体长度以上纤维各个长度进行分段测量。实验表明,本方法的测量结果与Y111结果高度相关,测量速度快。     

Finite Element Analysis of Concrete Structures Strengthened with Carbon Fiber Sheet

Stress redistributes after the concrete structures strenthened with carbon fiber reinforced polymer sheet. It is a question of secondary loading.Many scholars have studied it and got a lot of achievements.This paper summarizes the methods and analyzes their advantage and shortcoming. Based on it, a new method is proposed.The method is developing in large-scale general software-Ansys by using adding new elements, constitutive relationship, failure criterion,and so on.The calculation formula agrees with the experimental data.     

Study on New Technology of Compensation Network for Improving the Stability of Optical Fiber Sensor

THis Paper derscribes a novel all-fiber compensation network with three access-couplers for improving the stability of amplitude modulated fiber optical sensors. and its optimumstructure which is indepent on environment effects. We also describe the sealing method of the com-pensation network and the experiment of its coupler parameter variation caused by tempertare andvibration. The expreiment results showed that the compe nsation network can effectivelv resist themeasurement error affected by the in tensity variation of the optieal souce and other transmission loss.     

A New Car Lighting and Signals Control System Based on Optical Fiber Communication

The control signals of conventional car lighting and signal control system which is not possess self-diagnosing function are transmitted via special wiring harness, with which the drivers are not able to discover a trouble and an accident may be occur when car running. To solve the problem, a new control system based on optical fiber communication is proposed. Its fundamental control function, self-diagnosing function, hardware designing and software developing are introduced.     

Properties of Steel Fiber Asphalt Concrete and Its Application

To prevent asphalt pavement from cracking under low temperatures and prolong its fatigue life, we tested the properties of a new type of steel fiber asphalt pavement. The tests evaluated Marshall stability, dynamic ruts, and cleavage strength under both low and normal temperature conditions. We also analyzed the anti-corrosion property of steel fiber and the factors affecting the properties of the steel fiber asphalt mixture. The steel fiber asphalt pavement was installed on a highway in Chongqing, P. R. China to investigate the construction art of the steel fiber asphalt mixture and examine its effect in field use. The test results and concrete use in the field show that the cleavage strength and flexibility of steel fiber asphalt concrete increase due to the action of steel fiber. We conclude that the anti-cracking capacity of asphalt pavement under low temperature conditions can be improved by steel fiber. The construction art of steel fiber asphalt pavement is the same as common asphalt pavement without the necessity of anti-corrosion processing for steel fiber. The research results are useful for pavement material selection in low temperature regions and heavy traffic road pavement designs.     

Analysis of Fiber Renforced Concrete Beam-Column Joints Model

Due to the large stirrup ratio and reinforcement congest in beam-column joints, the ordinary reinforced concrete beam-column joints take inconvenience to construction. Cracked fiber renforced concrete (FRC) has strong bridge ability and better tensile performance so that it can replace part or all of the stirrups. Based on previous researches on resistance mechanism of reinforced concrete joints, a new model using FRC materials in the core zone of beam-column joints is presented. It is a kind of model in which horizontal shear supported by the diagonal strut mechanism and softening truss mechanism with a certain percentage. The calculation results of the model is compared with the existing test results. It is a bit conservative to specimens with low axial load ratio. However, the results are in line with the specimens with high axial load ratio. Therefore, the results totally demonstrate the rationality of the proposed model in this paper. Meanwhile, according to the proposed model, the shear capacity of beam-column joints can be not only calculated, it also check whether FRC compressive strength in core zone of joints and horizontal stirrup ratio meets design requirements, which has a higher practicability.     

Extraction of Cotton Fiber DNA and Its Application in Traceability

[Objective] To address the questions of lacking monitoring system for origins of varieties, this study explored a DNA extraction method suitable for cotton fiber, aiming to establish an identification system that uses cotton fiber DNA as a medium to trace the authenticity and cultivar of cotton varieties. [Method] By improving and optimizing the extraction method, the DNAs of cotton fibers at different days post anthesis and lint from different years were extracted and used as templates for routine polymerase chain reaction (PCR) amplification. 13 pairs of simple sequence repeat(SSR) primers were selected for SSR-PCR amplification using the DNA of Lu 1127, Shikang 126 and Ruiza 816. [Result] The DNA extraction method can extract cotton fiber DNAs of different developmental stages and different years. With the development of fiber, although the extracted DNA content is reduced, it can still meet the needs of downstream experiments. The extracted cotton fiber DNAs can be subjected to conventional PCR amplification, the PCR amplified bands were clear; 13 pairs of cotton SSR primers were used for SSR-PCR amplification of cotton fiber DNAs of Lu 1127, Shikang 126 and Ruiza 816, and a clear polymorphic band could be amplified and easily distinguished. [Conclusion] This extraction method is suitable for extracting genomic DNA of cotton fiber, and is satisfied with conventional PCR amplification with SSR markers. It is confirmed that the cotton fiber DNA molecular markers are feasible for tracing the source of cotton varieties, and it is expected to provide technical support for ensuring the safety of cotton industry.     

新型组合梁板连接中板的抗弯性能

在高层建筑结构设计中,由于上部荷载较大或梁的跨度较大,使得梁的截面高度较高,通常会影响建筑的有效层高和建筑的总体高度。为了减小各层梁板结构高度,有效增大各层净高,提出了一种钢箱梁嵌入现浇板的新型组合梁板连接方式。针对这种新型连接方式,对6个钢箱梁混凝土板组合连接区域进行了板承受支座负弯矩的单调加载试验,对比分析了采用钢箱梁嵌入混凝土板组合楼盖与传统栓钉连接组合楼盖中板抵抗支座负弯矩的性能差异;并利用ABAQUS对试件进行了有限元分析。试验与有限元分析结果表明：采用钢箱梁嵌入板连接组合方式,其混凝土板抵抗支座负弯矩的能力与传统连接方式板抵抗支座负弯矩能力没有明显差异。     

Real Time Monitoring System of Drilling State in the Different Places Based on Internet

On the basis of the Real Time Multi-parameter Monitoring System of Drilling Engineering, a new Internet-based Real Time Monitoring System of Drilling State in Different Places is developed. This system enables long-distance monitoring on the drilling field through the Internet. In the different places the basic data can be obtained from the drilling field, in this way the technology resource and expert resource in the different places can be taken full advantage to resolve the problem of the weak technology of the drilling team, and realize the long distance monitoring, long distance direction, and long-distance management. This system makes use of the popular network technology and data management technology, and adopts the Asp and Java to settle the key technology problem of the real time transmission and real time display.