流加糖流加速度对谷氨酸发酵的影响

在谷氨酸发酵生产中,流加糖工艺的控制对发酵中后期的产酸影响很大,不同的流加糖浓度和不同的流加糖速度均对发酵有不同程度的影响,下面通过实验数据,从不同的流加糖速度来探索发酵生产中流加糖工艺的控制。

彩色多普勒评价胎儿脑动脉及脐动脉血流加速度的价值研究

选取我院2013年3月~2014年3月间收治的186例妇产科分娩孕妇与孕期健康体检女性的临床资料,分析所有受检女性的临床资料,其中异常组42例,正常组144例。所有女性均接受彩色多普勒检查,分析这种检查方式在胎儿脑动脉及脐动脉血流加速度检测中的应用价值。结果（1）异常组的脐动脉AC与脑动脉AC值检测值低于正常组,两组对比有较大差异,存在统计学意义（P〈0.05）。（2）正常组的管径与动脉数量均多于对照组,对比有较大差异,存在统计学意义（P〈0.05）。彩色多普勒在胎儿脑动脉及脐动脉血流加速度的检测中有着较高的应用价值,可以对胎儿胎盘循环情况进行监测,便于尽早将胎儿循环障碍纠正,保证宫内安全。

盐酸坦索罗辛胶囊体内药物浓度与男性尿流率相关性研究

目的:检测健康青年男性口服盐酸坦索罗辛胶囊(哈乐)前后尿流率变化,了解药物浓度对尿流参数的影响。方法:对8例健康青年男性口服哈乐前后进行尿流测定和生命体征监测。服药前测定2次,服药后每2小时测定1次。服药后8h内每小时和第10、12、16、24、36、48、72h进行血药浓度测定。结果:尿流加速度在服药后3～6h明显增加(P<0.05),且与血药浓度曲线峰值一致;余与服药前无差异(P>0.05)。结论:哈乐效果与血药浓度密切相关,口服常规剂量(0.4mg)对青年男性尿流加速度有明显影响,对生命体征无影响。

弓网强电流滑动电接触摩擦振动分析与建模

在电气化铁路弓网系统中,受电弓滑板与接触线之间的摩擦振动加速度反映了弓网载流摩擦的接触状况,影响弓网的离线概率以及磨损状态。该文通过对弓网接触状态的分析,建立弓网摩擦副的弹簧-阻尼-质量模块摩擦振动模型。通过实验研究,在考虑法向压力、运行速度及电流强度三要素对摩擦振动的影响下,分析摩擦振动模型中特性参数和受力与三要素的函数关系;在此基础上,利用实验数据求解函数关系中的常数参数。最后通过实验验证摩擦振动模型的精确性,为进一步研究弓网系统的载流摩擦磨损机理以及离线概率提供理论依据。

旧金山湾地区的泥石流灾害

一些滑坡运动的速度迟缓，所造成的破坏是逐渐积累的；另一些滑坡运动的速度迅速，造成巨大的生命和财产损失，且是突发的和不可预见的。泥石流（也指泥滑、泥流或者岩屑崩塌）是一种常见的快速滑动滑坡类型，通常在强降雨期间由已饱和的土壤诱发。泥石流通常由陡峭山坡液化的土壤滑动或滑落引起，泥石流加速度为35英里/小时或更大，能够沿山坡和沟渠向下流动直至相对平缓的地面。

温度对糖蜜酒精发酵的影响

温度对酵母的生长繁殖影响很大,在用固定化酵母进行糖蜜酒精发酵过程中,温度的变化主要影响酵母起种时间的长短,糖液流加速度,以及发酵速度的快慢。

一种用于异常行为检测的运动特征描述子

目前,用于描述视频中人群的运动信息大多是基于光流的速度描述子。事实上,加速度蕴含丰富的运动信息,能够提供速度描述子在描述复杂运动模式时缺失的信息,以更好地表征复杂的运动模式。文中研究了一种运动特征描述子,使用受限玻尔兹曼机模型进行异常行为检测。首先,提取视频中的光流场信息,计算帧间加速度光流;然后,对一个时空块中的加速度信息进行直方图统计,将若干帧的所有时空块直方图特征进行拼接,从而获得加速度描述子;最后,在仅包含正常行为的训练集上建立受限玻尔兹曼机模型,在测试阶段根据测试视频重建特征与原始特征的误差大小进行异常检测。实验表明,所提出的加速度描述子结合速度描述子,在UMN数据集与UCF-Web数据集上,ROC曲线下的面积分别达到了0.984与0.958,相较于其他算法,所提方法取得了更高的异常行为检测准确率。

An Experimental Investigation on Solid Acceleration Length in the Riser of a Long Circulating Fluidized Bed

Systematic experimental work was conducted to investigate the solid acceleration length in a 16m long circulating fluidized bed riser with fluid cracking catalyst particles over a wide range of operating conditions. A more feasible method is proposed to determine the acceleration length from the measured axial profiles of pressure gradient (or apparent solid holdup). With this new method and large amount of experimental data, a clear picture on the variation of the acceleration length with both solid circulating rate and superficial gas velocity is obtained.It is found that the acceleration length increases generally with increasing solid flow rate and/or decreasing gas velocity. However, the trend in variation of the acceleration length with operating conditions are quite different in different operation ranges. Reasonable explanations are suggested for the observed variation patterns of acceleration length.

Passive Control of Turbulent Jet Flow with Wedged Nozzle

Turbulent flow field of the free jet with circular nozzle and wedged nozzles is measured using hot wire anemometry with resolution higher than the smallest turbulence time scale. Wavelet analysis is employed to perform multi-scale decomposition of instantaneous turbulence fluctuating velocity signals, and the energy distribution of the turbulent multi-scale eddy structures over scales is studied using wavelet coefficients. Investigation of the multi-scale eddy structures of circular jet and various wedged jets reveals the transport of the energy of these wedged jets in the space from the axis to the side of the jet, as compared with the circular jet. Furthermore, not only the eddy structures at the wedge tines in the near field are crashed, but also the interactions such as eddy structure union and entrainment take place at different longitudinal and normal locations along with the development of the jets because of the existence of wedges.

Characteristics of Clustering Debris Flows in Wenchuan Earthquake Zone

Clustering debris-flow events, namely many debris flows simultaneously triggered by a regional rainstorm in a large-scale mountainous area,occurred in four regions of Wenchuan earthquake stricken areas in 2008 and 2010. The characteristics of the clustering debris flows are examined with regard to triggering rainfall, formation process, and relationship with the earthquake by field survey and remote sensing interpretation. It is found that the clustering events occurred nearly at the same time with the local peak rainstorms, and the rainfall intensity-duration bottom limit line for clustering debris flows is higher than the worldwide line. It means that more rainfall is needed for the occurrence of the clustering debris flows. Four kinds of major formation processes for these debris flows are summarized: tributary-dominated, mainstreamdominated, transformation from slope failures, and mobilization or liquefaction of landslide. The four regions has a spatial correlation with the strongquake-influenced zone with the peak ground acceleration = 0.2 g and the seismic intensity > X.

Analysis of Phase Transition in Traffic Flow based on a New Model of Driving Decision

Different driving decisions will cause different processes of phase transition in traffic flow. To reveal the inner mechanism, this paper built a new cellular automaton （CA） model, based on the driving decision （DD）. In the DD model, a driver＇s decision is divided into three stages： decision-making, action, and result. The acceleration is taken as a decision variable and three core factors, i.e. distance between adjacent vehicles, their own velocity, and the preceding vehicle＇s velocity, are considered. Simulation results show that the DD model can simulate the synchronized flow effectively and describe the phase transition in traffic flow well. Further analyses illustrate that various density will cause the phase transition and the random probability will impact the process. Compared with the traditional NaSch model, the DD model considered the preceding vehicle＇s velocity, the deceleration limitation, and a safe distance, so it can depict closer to the driver preferences on pursuing safety, stability and fuel-saving and has strong theoretical innovation for future studies.

Converted-wave Seismology in Anisotropic Media Revisited, Part II: Application to Parameter Estimation

In transversely isotropic media with a vertical symmetry axis （VTI）, the converted-wave （C-wave） moveout over intermediate-to-far offsets is determined by four parameters. These are the C-wave stacking velocity Vc2 , the vertical and effective velocity ratios γ0 and γeff, and the anisotropic parameter χeff. We refer to the four parameters as the C-wave stacking velocity model. The purpose of C-wave velocity analysis is to determine this stacking velocity model. The C-wave stacking velocity model Vc2, γ0, γeff, and χeff can be determined from P-and C-wave reflection moveout data. However, error propagation is a severe problem in C-wave reflection-moveout inversion. The current short-spread stacking velocity as deduced from hyperbolic moveout does not provide sufficient accuracy to yield meaningful inverted values for the anisotropic parameters. The non-hyperbolic moveout over intermediate-offsets （x/z from 1.0 to 1.5） is no longer negligible and can be quantified using a background γ. Non-hyperbolic analysis with a γ correction over the intermediate offsets can yield Vc2 with errors less than 1% for noise free data. The procedure is very robust, allowing initial guesses of γ with up to 20% errors. It is also applicable for vertically inhomogeneous anisotropic media. This improved accuracy makes it possible to estimate anisotropic parameters using 4C seismic data. Two practical work flows are presented for this purpose： the double-scanning flow and the single-scanning flow. Applications to synthetic and real data show that the two flows yield results with similar accuracy but the single-scanning flow is more efficient than the double-scanning flow.

Optimized Design of Spacer in Electrodialyzer Using CFD Simulation Method

In this study, the effects of length-width ratio and diversion trench of the spacer on the fluid flow behavior in an electrodialyzer have been investigated through CFD simulation method. The relevant information, including the pressure drop, velocity vector distribution and shear stress distribution, demonstrates the importance of optimized design of the spacer in an electrodialysis process. The results show width of the diversion trench has a great effect on the fluid flow compared with length. Increase of the diversion trench width could strength the fluid flow, but also increase the pressure drop. Secondly, the dead zone of the fluid flow decreases with increase of length-width ratio of the spacer, but the pressure drop increases with the increase of length-width ratio of the spacer. So the appropriate length-width ratio of the space should be moderate.

A fast explicit finite difference method for determination of wellhead injection pressure

A fast explicit finite difference method (FEFDM),derived from the differential equations of one-dimensional steady pipe flow,was presented for calculation of wellhead injection pressure.Recalculation with a traditional numerical method of the same equations corroborates well the reliability and rate of FEFDM.Moreover,a flow rate estimate method was developed for the project whose injection rate has not been clearly determined.A wellhead pressure regime determined by this method was successfully applied to the trial injection operations in Shihezi formation of Shenhua CCS Project,which is a good practice verification of FEFDM.At last,this method was used to evaluate the effect of friction and acceleration terms on the flow equation on the wellhead pressure.The result shows that for deep wellbore,the friction term can be omitted when flow rate is low and in a wide range of velocity the acceleration term can always be deleted.It is also shown that with flow rate increasing,the friction term can no longer be neglected.

Modelling and Control of Pressurized Molten Metal in Press Casting

This paper presents a modeling and control of molten metal＇s pressure in pressing process using an innovative iron casting developed by our group. In this method, molten metal is directly poured into a lower mold, and then pressed to fill cavity by an upper mold being lowered down. For complex liquid flow during pressing, the liquid＇s pressure changing inside vertical path with various contraction and expansion geometries is newly modeled via the unstationary Bernoulli equation. The mathematical model is derived for a control design of pressing. To conduct the pressing velocity design algorithm, an unknown parameter of proposed model considering viscous flow is identified by using CFD （Computational Fluid Dynamics） with heat flow calculation. Control performance using a multi-switching velocity pattern is confirmed as an effective control design using the pressure model, because the pressure fluctuation has discontinuous variation points. Substituting detailed information for mold shape, poured volume and initial temperature into a developed control input generator, an optimum pressing velocity design and a robust design for defect-free production are proposed by the design algorithm based on the construction of an inverse system comprised of the sequential switching from higher to lower speed. Consequently, the effectiveness of the pressing control with reasonable pressure suppression has been demonstrated through CFD.

Experimental study of traffic-induced vibration of the new CCTV headquarters building

The traffic-induced vibrations of the new CCTV Headquarters building are studied stages. In the first stage when the through experiments in two 30th floor of the northwest tower and the 38th floor of the southeast tower were finished, the traffic flows on the roads surrounding the building were investigated, and 27 setups of accelerations were measured at the roadside, on the pile cap and on the 9th floor. In the second stage when the whole steel structure was completed, l 5 setups of accelerations were measured at the roadside, on the pile cap and on the 37th and the 48th floors. The accelerations of the building under different traffic flows, in different positions are analyzed in both time domain and frequency domain. The damping ratios are estimated by the upgraded half-power bandwidth method.

Emittance Measurement at BEPCⅡ Linac

Further studies on beam emittance measurement have been made to improve the emittance measurement precision at BEPCⅡ linac.Some problems in the measurement are solved and a code for beam emittance calculation is developed.With these improvements,the emittance measurement precision was upgraded.

An in-plane low-noise accelerometer fabricated with an improved process flow

We present a bulk micromachined in-plane capacitive accelerometer fabricated with an improved process flow,by etching only one-fifth of the wafer thickness at the back of the silicon while forming the bar-structure electrode for the sensing capacitor.The improved flow greatly lowers the footing effect during deep reactive ion etching(DRIE),and increases the proof mass by 54% compared to the traditional way,resulting in both improved device quality and a higher yield rate.Acceleration in the X direction is sensed capacitively by varying the overlapped area of a differential capacitor pair,which eliminates the nonlinear behavior by fixing the parallel-plate gap.The damping coefficient of the sensing motion is low due to the slide-film damping.A large proof mass is made using DRIE,which also ensures that dimensions of the spring beams in the Y and Z directions can be made large to lower cross axis coupling and increase the pull-in voltage.The theoretical Brownian noise floor is 0.47 μg/Hz1/2 at room temperature and atmospheric pressure.The tested frequency response of a prototype complies with the low damping design scheme.Output data for input acceleration from ?1 g to 1 g are recorded by a digital multimeter and show very good linearity.The tested random bias of the prototype is 130 μg at an averaging time of around 6 s.

Numerical prediction of the flow property in round turbulent jet of fiber suspension

The equation of probability distribution function for mean fiber orientation,and the equations of Reynolds averaged NavierStokes,turbulence kinetic energy and turbulence dissipation rate with the additional term of the fibers are derived and solved numerically.The effects of fiber concentration and fiber aspect-ratio on the mean velocity profile,turbulent kinetic energy and turbulent viscosity are analyzed.The results show that the mean axial velocity gradient increases near the centerline and decreases near the outside,respectively,as the fiber concentration increases.The mean axial velocity decreases with increasing the fiber concentration at the same radial positions.The centerline mean axial velocity decreases with axial distance,and this phenomenon is more obvious as the fiber concentration increases.The turbulent kinetic energy and turbulent viscosity increase over the jet region with an increasing fiber concentration.The variation tendency of mean axial velocity,turbulence kinetic energy and turbulence viscosity with fiber aspect-ratio is the same as that with fiber concentration.The difference is that the variation with fiber concentration is more obvious than with fiber aspect-ratio.