大跨径长箱涵现浇钢筋砼箱身模板平移技术

山东省济南市大辛河支沟现浇钢筋砼箱涵净跨径5m、净高3.5m,总长145m。本文就箱身内、外模板采用平移技术,改变传统支模方法:拼装—拆散—再拼装—再拆散……进行介绍。从技术控制和成本效益上论述移模技术能够大大减少材料消耗、降低成本、加快施工进度的,缩短工期、取得最佳经济效益的可行性。

橡胶移模工艺技术的研究与应用

依据橡胶后硫化效应原理,通过优化模压工艺,采用外层底单独提前生产、内层底改为刀钺冲裁、帮脚粘贴胶围条、内层胶片冲出孔洞、外层底模具尺寸调整的工艺措施,创新性的提出橡胶移模工艺。结果显示,成品鞋底质量达到德国德士玛连帮注射转盘机双密度硫化成型工艺技术水平,使企业原有长期闲置的模压设备能够更好的发挥应有的作用。

基于L型槽结构的小型化SIW滤波器

为了解决传统基片集成波导(SIW)滤波器在通信电路中占用空间较大的问题,提出一种新型的开槽方法实现了小型化SIW滤波器。通过在四分之一模基片集成波导(QMSIW)谐振腔的顶层金属板上蚀刻L型谐振槽,利用开槽扰动的模移技术原理,使QMSIW腔的谐振基模被移动到低频处。基于此,设计了一款中心频率为2.6 GHz,相对带宽为8.6%的二阶准椭圆响应带通滤波器,且在通带外的上下阻带给出了传输零点,提高了滤波器的选择性。实际测试的S参数与仿真结果吻合,表明蚀刻L型槽结构可以实现小型化和高选择性。

Numerical Simulation of Asynchronous Simulated Moving Bed Chromatography

Asynchronous simulated moving bed chromatography (ASMBC), known also as the 'VARICOL' process, is more efficient and flexible than the well-known and traditional simulated moving bed chromatography (SMBC). A detailed model of ASMBC, taking account of non-linear competitive isotherms, mass transfer parameters, and complex port switching schedule parameters, was developed to simulate the complex dynamics of ASMBC.The simulated performance is in close agreement with the experimental data of chiral separation reported in the literature. The simulation results show that ASMBC can achieve the performance similar to SMBC with fewer columns and can achieve better performance than SMBC with the same total column number. All design and operation parameters can be chosen correctly by numerical simulation. This detailed ASMBC model and the numerical technique are useful for design, operation, optimization and scale-up of ASMBC.

Heat Transfer in Nucleate Pool Boiling of Binary and Ternary Refrigerant Mixtures

Heat transfer coefficients in nucleate pool boiling were measured on a horizontal copper surface for refrigerants, HFC-134a, HFC-32, and HFC-125, their binary and ternary mixtures under saturated conditions at 0.9MPa. Compared to pure components, both binary and ternary mixtures showed lower heat transfer coefficients.This deterioration was more pronounced as heat flux was increased. Experimental data were compared with some empirical and semi-empirical correlations available in literature. For binary mixture, the accuracy of the correlations varied considerably with mixtures and the heat flux. Experimental data for HFC-32/134a/125 were also compared with available correlated equation obtained by Thome. For ternary mixture, the boiling range of binary mixture composed by the pure fluids with the lowest and the medium boiling points, and their concentration difference had important effects on boiling heat transfer coefficients.

Numerical simulation and analysis of solid-liquid two-phase threedimensional unsteady flow in centrifugal slurry pump

Based on RNG k-ε turbulence model and sliding grid technique, solid-liquid two-phase three-dimensional(3-D) unsteady turbulence of full passage in slurry pump was simulated by means of Fluent software. The effects of unsteady flow characteristics on solid-liquid two-phase flow and pump performance were researched under design condition. The results show that clocking effect has a significant influence on the flow in pump, and the fluctuation of flow velocity and pressure is obvious, particularly near the volute tongue, at the position of small sections of volute and within diffuser. Clocking effect has a more influence on liquid-phase than on solid-phase, and the wake-jet structure of relative velocity of solid-phase is less obvious than liquid-phase near the volute tongue and the impeller passage outlet. The fluctuation of relative velocity of solid-phase flow is 7.6% smaller than liquid-phase flow at the impeller outlet on circular path. Head and radial forces of the impeller are 8.1% and 85.7% of fluctuation, respectively. The results provide a theoretical basis for further research for turbulence, improving efficient, reducing the hydraulic losses and wear. Finally, field tests were carried out to verify the operation and wear of slurry pump.

A hybrid model of a subminiature helicopter in horizontal turn

A hybrid model of a subminiature helicopter in horizontal turn is presented. This model is based on a mechanism model and its compensated neural network （NN）. First, the nonlinear dynamics of a sub-miniature helicopter is established. Through the linearization of the nonlinear dynamics on a trim point, the linear time-invariant mechanism model in horizontal turn is obtained. Then a diagonal recursive neural network is used to compensate the model error between the mechanism model and the nonlinear model, thus the hybrid model of a subminiature helicopter in horizontal turn is achieved. Simulation results show that the hybrid model has higher accuracy than the mechanism model and the obtained compensated-NN has good generalization capability.

Soil-Vegetation-Atmosphere Radiative Transfer Model in Microwave Region

The radiative transfer is one of the significant theories that describe the processes of scattering, emission, and absorption of electromagnetic radiant intensity through scattering medium. It is the basis of the study on the quan-titative remote sensing. In this paper, the radiative characteristics of soil, vegetation, and atmosphere were described respectively. The numerical solution of radiative transfer was accomplished by Successive Orders of Scattering (SOS). A radiative transfer model for simulating microwave brightness temperature over land surfaces was constructed, de-signed, and implemented. Analyzing the database generated from soil-vegetation-atmosphere radiative transfer model under Advanced Microwave Scanning Radiometer-Earth Observing System (AMSR-E) configuration showed that the atmospheric effects on microwave brightness temperature should not be neglected, particularly for higher frequency, and can be parameterized. At the same time, the relationship between the emissivities of the different channels was developed. The study results will promote the development of algorithm to retrieve geophysical parameters from mi-crowave remotely sensed data.

Implementation technology of Kirchhoff demigration

Demigration refers to directly applying a specific imaging technique to a migrated section. It is applied primarily to seismic data mapping. In a previous research study, a time-efficient implementation technology of demigration was expounded. In the present study, the Fast Marching Method （FMM） used for traveltime computation in the isochrone-staek demigration, is developed. Furthermore, other key techniques （ such as selection of aperture and antialiasing filtering factor） are analyzed in detail. Besides, the detail implementation method and program flow are given, which is shown their good computational efficiency and high-quality demi- gration effect. This implementation technique is illustrated with both the V（z） model and Marmousi model. It provides a basic method for implementing demigration in the application of seismic data mapping.

Electro-Mechanical Phase Shifters Based on MEMS Structure

The aim of the study of phase shifter on MEMS （micro-electro-mechanical systems） structures was to minimize the dimensions of the design achievement. Also, the main task was to achieve the reliability and durability of the device. The calculation was based on the optimization technique （step by step） and the modeling of individual parts of the device, namely MEMS-keys that perform the main function--switching. The urgency of this problem is the development and study of one device as a universal, that is, automatically switches from two signals simultaneously. Designs are original and devises are the intellectual property of the authors. The program for modeling phase shifters Computer Simulation Technology Microwave Studio and its results are presented in the paper.

Chromatic Dispersion Monitoring Method Based on Phase Shift Technique

The modulation phase shift method was used to measure chromatic dispersion in a standard single mode fiber for telecommunication. The modulation phase difference of the transmitted light at the wavelength of 1532.16 nm modulated by a radio frequency signal was measured, relative to the transmitted light at the wavelength of 1549.33 nm modulated by the same signal. By introducing a reference light at the wavelength of 1310 nm, a 1310/1550 nm wavelength division multiplexing was used instead of the high cost dense wavelength division multiplexing. In the experiment, two testing lights were coupled with the reference light to the fiber spools of different lengths, respectively. By finite difference method, the chromatic dispersion between the two testing lights was measured, and the fixed errors generated during transmission were less than 0.5 ps/(nm·km).

Application of the Moving Averaging Technique in Surplus Production Models

Surplus production models are the simplest analytical methods effective for fish stock assessment and fisheries management. In this paper, eight surplus production estimators(three estimation procedures) were tested on Schaefer and Fox type simulated data in three simulated fisheries(declining, well-managed, and restoring fisheries) at two white noise levels. Monte Carlo simulation was conducted to verify the utility of moving averaging(MA), which was an important technique for reducing the effect of noise in data in these models. The relative estimation error(REE) of maximum sustainable yield(MSY) was used as an indicator for the analysis, and one-way ANOVA was applied to test the significance of the REE calculated at four levels of MA. Simulation results suggested that increasing the value of MA could significantly improve the performance of the surplus production model(low REE) in all cases when the white noise level was low(coefficient of variation(CV) = 0.02). However, when the white noise level increased(CV= 0.25), adding the value of MA could still significantly enhance the performance of most models. Our results indicated that the best model performance occurred frequently when MA was equal to 3; however, some exceptions were observed when MA was higher.

Entry and technology transfer in a Cournot model

This work studies entry and technology transfer in a Cournot model where there are two domestic firms. A foreign firm has a patent on a technological innovation that reduces the costs of all firms. The foreign firm can license the innovation to one or both domestic firms. The authors consider two standard licensing policies： （1） auction policy and （2） unit royalty policy. The foreign firm can license the innovation either by staying outside the domestic market, or it can enter the market, license the innovation and compete with the domestic firms. The authors show that （1） when the foreign firm stays outside, it is never optimal for it to use royalties, （2） if it licenses the innovation by entering the industry, then royalties could be optimal and （3） when it decides on its entry strategy by taking its optimal licensing policies into account, it always finds it optimal to enter the domestic market.

A COMBINED ADMISSION CONTROL ALGORITHM WITH DA PROTOCOL FOR SATELLITE ATM NETWORKS

Admission control is an important strategy for Quality of Service (QoS) provisioning in Asynchro- nous Transfer Mode (ATM) networks. Based on a control-theory model of resources on-Demand Allocation (DA) protocol, the paper studies the effect of the protocol on the statistical characteristics of network traffic, and proposes a combined connection admission control algorithm with the DA protocol to achieve full utiliza- tion of link resources in satellite communication systems. The proposed algorithm is based on the cross-layer-design approach. Theoretical analysis and system simulation results show that the proposed algo- rithm can admit more connections within certain admission thresholds than one that does not take into account the DA protocol. Thus, the proposed algorithm can increase admission ratio of traffic sources for satellite ATM networks and improve satellite link utilization.

Migration and distribution of bone marrow stromal cells in injured spinal cord with different transplantation techniques

Objective： To study the regularity of migration and distribution of bone marrow stromal cells （BMSCs） in injured spinal cord with intradural space transplantation. Methods： Forty Wistar rats were randomly assigned into 4 groups. The spinal cord injury model was prepared according to the modified Allen method. BMSCs were labeled by CM-Dil. And 5.0x 10^6 cells were transplanted by different channels including intraventricular injection （Group A）,injured spinal cord intrathecally injection （Group B）, remote intrathecally injection at the L3-L4 level （Group C）, and intravenous injection （Group D）. Spinal cord was dissected at 24 hours, 1, 2, 3 and 4 weeks after transplantation. Sections of 4 μm were cut on a cryostat and observed under fluorescence microscopy. Results： No fluorescence was observed 24 hours aftertransplantation in spinal cord injury parenchyma except Group B. One week later, BMSCs in Groups A and C began to migrate to the injured parenchyma; 2-4 weeks later, BMSCs penetrated into the injured parenchyma except Group D. The number of BMSCs decreased at 3-4 weeks after transplantation. The number of cells in Group B decreased faster than that of Groups A and C. Conclusions： BMSCs transplanted through intraventricular injection, injured spinal cord intrathecally injection and remote intrathecal injection could migrate to the injured parenchyma of spinal cord effectively. The number of BMSCs migrated into injured spinal cord parenchyma is rare by intravenous injection.

Theoretical and experimental investigation on bridge-borne noise under moving high-speed train

Bridge-borne noise pollution caused by train-induced bridge vibration has attracted more and more attentions due to its low-frequency characteristic.In order to investigate the numerical simulation technique of bridge-borne noise and noise reduction methods,a simply supported prestressed concrete (PC) box-girder bridge is adopted for study.Based on train-track-bridge interaction theory,the dynamic response of the bridge under a moving high-speed train is calculated in time-domain and assumed as the sound source of bridge-borne noise.Then bridge-borne noise is estimated according to boundary element method (BEM) in frequency-domain.The time-frequency transform is conducted by fast Fourier transformation (FFT).The validity of the numerical simulation technique is verified through comparison with field measurement results.Furthermore,noise reduction methods are proposed and corresponding effects are discussed.Results show that the proposed numerical simulation method is feasible and accurate in assessing bridge-borne noise.The dominant frequencies of bridge vibration and bridgeborne noise range from 40 Hz to125 Hz and from 31.5 Hz to 100 Hz,respectively.The peak frequency of bridge-borne noise near the bottom plate is 63 Hz.Increasing the thickness of deck plate,adjusting the inclination of webs to 0°-12°,strengthening the boundary constraints and adding a longitudinal clapboard are very effective noise control measures.

Fabrication of Tailored Bragg Gratings by the Phase Mask Dithering/Moving Technique

The most relevant aspects related to the phase mask dithering/moving method for the fabrication of complex Bragg grating designs are reviewed. Details for experimental implementation of this technique is presented, including theoretical analysis of the calibration functions for the correct dither/displacement. Results from tailored Bragg grating structures fabricated by this method are shown. Apodized Bragg gratings with modeled spatial profiles were implemented, resulting in side mode suppression levels of more than 20 dB in gratings showing transmission filtering level higher than 30 dB. Chirped gratings with the spectral bandwidth up to 4 nm, π-shift and sampled Bragg gratings with equalized peaks equally spaced by 0.8 nm （100 GHz） were also fabricated.