混纺试样束强测试中的实验方法

探讨混纺试样束强测试的实验方法 .采用澳大利亚 CSIRO研究所生产的SIROLAN-TENSOR束强测试仪 ,手工混制不同混纺比的毛涤试样 ,通过实验作比例分析 ,制定出可行的混纺试样测试方法 (平铺式测试法 )

棉纤维生长各阶段的土壤水分状况对其束强的影响

在纤维伸长前期、填充后期充足的土壤水分对提高束强有利,纤维生长扭曲期土壤干旱对提高束强有利,反之则不利。

原棉束强与铃期、铃期平均温度、棉铃吐絮日期关系的试验研究

原棉束强与铃期、铃期平均温度呈曲线相关,当铃期平均温度在30℃以上时,铃期大幅度缩短,束强随温度升高、铃期缩短而迅速增大;当铃期平均温度在30℃以下时,铃期随温度降低而缓慢变长,束强随铃期、温度变化不大。只有在吐鲁番9月上旬以前原棉东强与吐絮日期呈高度反相关,南北疆及9月中以后的吐鲁番等地,原棉束强一般与吐絮日期无关。

碱束斯特恩-盖拉赫实验

利用 K束斯特恩 -盖拉赫实验装置 ,通过对束源和表面电离探测器的改进 ,实现 Li,Na,K,Rb,Cs全碱束斯特恩 -盖拉赫实验 .

分子束梯形束形计算

本文对截面为矩形的窄束给出束强分布的图解法证明,并提出计算束强的精确公式。

施特恩-格拉赫实验束形分析

对于施特恩-格拉赫实验,实验者通常是根据实验得到的束强分布与束强分布函数的符合程度来评价实验结果的.本文结合一系列专题实验,系统地讨论了束强分布函数的来源、基本形式、适用范围及应用时应注意的一些问题.

某些棉花品质指标相互关系的探讨

目前,新疆棉花品质问题研究中,经常遇到的一个问题,就是某些棉花品质指标相互关系问题。如:我国常用的细度、国际常用特克斯、麦克隆值;又如单强、束强、卜强;也有翻译问题,如有的把同一单位一克/特克斯翻成不同的名称:有叫强力的,也有叫束强的。搞清楚类似棉花品质指标之间的关系,对充分利用现有资料、充分利用现有仪器都有重要意义。为此,翻译了苏联植棉业大百科全书中有关条目,对照中国棉花栽培学中有关论述,经反复推敲,现将主要结果报告于下,与同志们讨论。

Strength of circular concrete columns under concentric compression

An experimental study, in which six columns were loaded concentrically toinvestigate the behavior of reinforced normal strength and high strength circular columns underconcentric compression, is described. The concrete strengths of the columns were 30 MPa and 60 MPa.The primary variables considered were the concrete strength and the amount of transversereinforcement. Test results indicate that smaller hoop spacing provides higher column capacity andgreater strength enhancement in a confined concrete core of columns. For the same lateralconfinement, high strength concrete columns develop lower strength enhancement than normal strengthconcrete columns. Both the strength enhancement ratio (f'_(cc) /f'_(co)) and the column capacityratio (P_(test)/P_o) were observed to show linear increase variations with rho_s f_(yt)/f'_c incircular columns.

Surface modification of Cu-25Cr alloy induced by high current pulsed electron beam

A Cu-25Cr alloy prepared by vacuum induction melting method was treated by the high current pulsed electron beam （HCPEB） with pulse numbers ranging from 1 to 100. Surface morphologies and microstructures of the alloy before and after the treatment were investigated by scanning electron microscopy and X-ray diffraction. The results show that significant surface modification can be induced by HCPEB with the pulse number reaching 10. Craters with typical morphologies on the Cu-25Cr alloy surface are formed due to the dynamic thermal field induced by the HCPEB. Micro-cracks, as a unique feature, are well revealed in the irradiated Cu-25Cr specimens and attributed to quasi-static thermal stresses accumulated along the specimen surface. The amount of cracks is found to increase with the pulse number and a preference of these cracks to Cr phases rather than Cu phases is also noted. Another characteristic produced by the HCPEB is the fine Cr spheroids, which are determined to be due to occurrence of liquid phase separation in the Cu-25Cr alloy. In addition, an examination on surface roughness of all specimens reveals that more pulses will produce a roughened surface, as a result of compromising the above features.

脱胶大麻纤维强力试验方法研究

本文运用正交试验及统计分析方法,优选了大麻纤维束强的有关试验参数,确定了合理的试验方案,并与大麻纤维单强进行了相关分析,得出了大麻纤维单强与束强线性相关的结论,说明了两种方法的可行性。

Ultimate flexural strength of normal section of FRP-confined RC circular columns

Numerical analysis is carried out to study the sectional properties of the fiber-reinforced polymer（FRP）-confined reinforced concrete（RC）circular columns. The axial load ratio, the FRP confinement ratio and the longitudinal reinforcement characteristic value are the three main parameters that can influence the neutral axis depth when concrete compression strain reaches an ultimate value. The formula for computing the central angle θ, corresponding to the compression zone, is established according to the data regression of the numerical analysis results. The numerical analysis results demonstrate that the concrete stress enhancement from transverse confinement and strain hardening of the longitudinal reinforcement can cause a much greater flexural strength than that defined by the design code. Based on the analytical studies and the test results of 36 large scale columns, the formula to calculate the flexural strength when columns fail under seismic loading is proposed, and the calculated results agree well with the test results. Finally, parametric studies are conducted on a typical column with different axial load ratios, longitudinal reinforcement characteristic value and FRP confinement ratios. Analysis of the results shows that the calculated flexural strength can be increased by 50% compared to that of unconfined columns defined by the code.

网

我是一条大草鱼,"高龄"5岁,住在一个湖里。我的伙伴不断被一个叫网的东西捕获,幸好我聪明,夜间才到岸边去,白天最多在湖中间露一露面,一有船来就往深水里钻,因此,才得如此"高寿"。一天晚上,我到岸边觅食,忽然,一束强光照得我头昏眼花,只听"嗖"的一声,我就被什么东西缠住了。我知道那是网。我拼命地挣扎,可那东西越缠越紧,最后。

月下独步

很久没像今晚这样独自在月下漫步了。这并不是说自己很少单独出门,抑或说已与月色久违。而是说像今晚这种状态：不是因为任何事由出来,就是想出去走走,甚或说都没有想到欣赏月色,只是在不经意间与她邂逅。但今晚的月色却美得超出我的想象：深蓝的天幕上,零星点缀着几颗星子,将夜空衬托得格外深邃和单纯;一轮明月.

Yielding and fracture behaviors of coarse-grain/ultrafine-grain heterogeneous-structured copper with transitional interface

Heterogeneous-structured Cu samples composed of coarse-grained(CG) and ultrafine-grained(UFG) domains with a transitional interface were fabricated by friction stir processing, in order to investigate the effect of interface constraint on the yielding and fracture behaviors. Tensile test revealed that the synergetic strengthening induced by elastic/plastic interaction between incompatible domains increases with increasing the area of constraint interface. The strain distribution near interface and the fracture morphology were characterized using digital image correlation technique and scanning electron microscopy, respectively. Fracture dimples preferentially formed at the interface, possibly due to extremely high triaxial stress and strain accumulation near the interface. Surprisingly, the CG domain was fractured by pure shear instead of the expected voids growth caused by tensile stress.

A comprehensive comparison on vibration and heat transfer of two elastic heat transfer tube bundles

Elastic heat transfer tube bundles are widely used in the field of flow-induced vibration heat transfer enhancement. Two types of mainly used tube bundles, the planar elastic tube bundle and the conical spiral tube bundle were comprehensively compared in the condition of the same shell side diameter. The natural mode characteristics, the effect of fluid-structure interaction, the stress distribution, the comprehensive heat transfer performance and the secondary fluid flow of the two elastic tube bundles were all concluded and compared. The results show that the natural frequency and the critical velocity of vibration buckling of the planar elastic tube bundle are larger than those of the conical spiral tube bundle, while the stress distribution and the comprehensive heat transfer performance of the conical spiral tube bundle are relatively better.

Instantaneous phase inversion based on an unwrapping algorithm

The full-waveform inversion method is a high-precision inversion method based on the minimization of the misfit between the synthetic seismograms and the observed data.However,this method suffers from cycle skipping in the time domain or phase wrapping in the frequency because of the inaccurate initial velocity or the lack of low-frequency information.furthermore,the object scale of inversion is affected by the observation system and wavelet bandwidth,the inversion for large-scale structures is a strongly nonlinear problem that is considerably difficult to solve.In this study,we modify the unwrapping algorithm to obtain accurate unwrapped instantaneous phase,then using this phase conducts the inversion for reducing the strong nonlinearity.The normal instantaneous phases are measured as modulo 2π,leading the loss of true phase information.The path integral algorithm can be used to unwrap the instantaneous phase of the seismograms having time series and onedimensional(1 D)signal characteristics.However,the unwrapped phase is easily affected by the numerical simulation and phase calculations,resulting in the low resolution of inversion parameters.To increase the noise resistance and ensure the inversion accuracy,we present an improved unwrapping method by adding an envelope into the path integral unwrapping algorithm for restricting the phase mutation points,getting accurate instantaneous phase.The objective function constructed by unwrapping instantaneous phase is less affected by the local minimum,thereby making it suitable for full-waveform inversion.Further,the corresponding instantaneous phase inversion formulas are provided.Using the improved algorithm,we can invert the low-wavenumber components of the underneath structure and ensure the accuracy of the inverted velocity.Finally,the numerical tests of the 2 D Marmousi model and 3 D SEG/EAGE salt model prove the accuracy of the proposed algorithm and the ability to restore largescale low-wavenumber structures,respectively.

Network traffic flow evolution with battery electric vehicles and conventional gasoline vehicles

In order to investigate the effect of the use of battery electric vehicles on traffic dynamics,the valid paths of electric battery vehicles are defined and a check-based method is proposed to obtain them.Then,assuming that travelers only focus on their past travel experience,a day-to-day traffic assignment model is established based on reinforcement learning and bounded rationality.In the proposed model,the Bush-Mosteller model,a reinforcement learning model,is modified to calculate path choice probability according to bounded rationality.The modified model updates the path choice probability only if the gap between expected travel time and perceived travel time is beyond the cognitive threshold.Numerical experiments validate the effectiveness of the model and show that traffic flows can converge to the equilibrium in any case of cognitive thresholds and penetration rates of battery electric vehicles.The cognitive threshold has a positive influence on the variation of traffic flows while it has a negative influence on the differences between traffic flows.The adaptation of battery electric vehicles leads to the poor performance of the traffic system.

Multi-goal Control of Chaotic Connected Complex Networks

Beam transport network(BTN)with small world(SW)(so-called BTN-SW)and Lorenz chaotic connectednetwork with scale-free(SF)are taken as two typical examples,we proposed a global linear coupling and combined withlocal error feedback methods in sub-networks to realize multi-goal control method of halo and chaos in two networksabove.The simulation results show that the methods above is effective for any chaotic connected networks and has apotential of applications in based-halo-chaos secure communication.

Performance of Cross-Shaped Concrete Columns Confined by Stirrups

The stress-strain curves of confined concrete were obtained based on tests of seven cross-shaped columns confined by stirrups under axial load. The experiment results showed that the strength and deformation of confined concrete can be enhanced effectively by stirrups for cross-shaped columns. Compared with the non-confined concrete, when the stirrup characteristic value is in the range of 0.046-0.230, the confined concrete compressive strengths has an increase of 8%-43%, and the strain corresponding to the peak stress of confined concrete has an increase of 25%-195%. According to the test results, the effects of stirrup characteristic and stirrup spacing on the compressive strength and strain of confined concrete were analysed. It is shown that the compressive strength of confined concrete has a linear relationship with the product of stirrup characteristic value and stirrup effective restraint coefficient, and the strain corresponding to the peak stress of confined concrete has a nonlinear relationship with the product of stirrup characteristic value and stirrup effective restraint coefficient. The stress-strain curve equation of confined concrete was proposed for cross-shaped columns, and the calculated curves are in good agreement with the experimental curves.

SAR IMAGE ENHANCEMENT BASED ON BEAM SHARPENING TECHNIQUE

A major problem encountered in enhancing SAR image is the total loss of phase information and the unknown parameters of imaging system. The beam sharpening technique, combined with synthetic aperture radiation pattern estimation provides an approach to process this kind of data to achieve higher apparent resolution. Based on the criterion of minimizing the expected quadratic estimation error, an optimum FIR filter with a symmetrical structure is designed whose coefficients depend on the azimuth response of local isolated prominent points because this response can be approximately regarded as the synthetic aperture radiation pattern of the imaging system. The point target simulation shows that the angular resolution is improved by a ratio of almost two to one. The processing results of a live SAR image demonstrate the validity of the method.