Life-Cycle Bearing Capacity for Pre-Stressed T-beams Based on Full-Scale Destructive Test

To investigate the evolution of load-bearing characteristics of pre-stressed beams throughout their service life and to provide a basis for accurately assessing the actual working state of damaged pre-stressed concrete T-beams,destructive tests were conducted on full-scale pre-stressed concrete beams.Based on the measurement and ana-lysis of beam deflection,strain,and crack development under various loading levels during the research tests,combined with the verification coefficient indicators specified in the codes,the verification coefficients of bridges at different stages of damage can be examined.The results indicate that the T-beams experience complete,incom-plete linear,and non-linear stages during the destructive test process.In the complete linear elastic stage,both the deflection and bottom strain verification coefficients comply with the specifications,indicating a good structural load-bearing capacity no longer adheres to the code’s requirements.In the non-linear stage,both coefficients exhi-bit a sharp increase,resulting in a further decrease in the structure’s load-bearing capacity.According to the pro-visions of the current code,the beam can be in the incomplete linear stage when both values fall within the code’s specified range.The strain verification coefficient sourced from the compression zone at the bottom of theflange is not recommended for assessing the bridge’s load-bearing capacity.

Design and process test of a novel MOEMS accelerometer based on Raman-Nath diffraction

A novel micro-opto-electro-mechanical system （MOEMS） accelerometer based on Raman-Nath diffraction is presented. It mainly consists of an FPW delay line oscillator and optical strip waveguides. The fun- damental theories and principles of the device are introduced briefly. A flexural plate-wave delay-line oscillator is designed to work as an acousto-optic （AO） shifter, which has a Klein-Cook parameter of 0.38. Single-mode optical strip waveguides of 2 μm in width and thicknesses of 0.6 μm are designed by using the effective index method for light transmission. The E^y00 mode waveguide polarizers are designed to ensure the consistency of the light polarization in the waveguides. The fabrication process, based on （100） oriented, 450-#m-thick silicon wafers is proposed in detail, and some difficulties in the process are discussed carefully. At last, a series of process tests are undertaken to solve the proposed problems. The results indicate that the proposed design and fabrication process of the device is dependable and realizable.

Optimization of Extraction Process of Zihua Qinghuo Capsule by Orthogonal Test

With quercetin content and yield of dry extract as investigation indices, three factors, amount of water added, decoction time and decoction times were investigated by an orthogonal test, so as to select the optimal water extraction process for Zihua Qinghuo Capsule. The determined extraction process was adding 8 times of water in five herbs including Viola philippica and decocting for 2 times, 1.5 h each time. Pilot scale test demonstrated that the selected process is stable and feasible, and could provide reliable reference for practical production.

Lognormal Process Software Reliability Modeling with Testing-Effort

We propose a software reliability growth model with testing-effort based on a continuous-state space stochastic process, such as a lognormal process, and conduct its goodness-of-fit evaluation. We also discuss a parameter estimation method of our model. Then, we derive several software reliability assessment measures by the probability distribution of its solution process, and compare our model with existing continuous-state space software reliability growth models in terms of the mean square error and the Akaike’s information criterion by using actual fault count data.

甘薯杂粮粉品质特征与主要理化性质的Mantel test分析

以不同品种甘薯全粉为原料,复配黄豆粉、芝麻粉制备甘薯杂粮粉,并测定其β-胡萝卜素、玉米黄质、槲皮素含量,利用曼特尔检验(Mantel test)方法探讨这3种天然成分含量与其理化指标之间的相关性,研究甘薯品种对甘薯杂粮粉品质的影响。结果表明:甘薯杂粮粉的抗氧化能力与β-胡萝卜素含量呈强正相关(r=0.80),与玉米黄质含量(r=0.26)和槲皮素含量(r=-0.14)呈现弱相关性。甘薯杂粮粉的干物质含量与β-胡萝卜素含量呈负相关(r=-0.72),与玉米黄质含量(r=0.91)和槲皮素含量(r=1.00)呈强正相关。总体表明β-胡萝卜素是甘薯杂粮粉中有效的抗氧化成分。

Uniaxial compression CT and acoustic emission test on the coal crack propagation destruction process

Acoustic emission test and CT scanning are important techniques in the study of coal crack propagation. A uniaxial compression test was performed on coal samples by integrating CT and acoustic emission. The test comparison analyzes the acoustic emission load and CT images for an effective observation on the entire process, from crack propagation to the samples＇ destruction. The box dimension of the coal samples＇ acoustic emission series and the CT images were obtained through calculations by using the authors＇ own program. The results show that the fractal dimension of both the acoustic emission energy and CT image increase rapidly, indicating coal and rock mass has entered a dangerous condition. Hence, measures should be taken to unload the pressure of the coal and rock mass. The test results provide intuitive observation data for the coal meso-damage model. The test contributes to in-depth studies of coal or rock crack propagation mechanisms and provides a theoretical basis for rock burst mechanism.

Kolmogorov-Smirnov APF Test for Inhomogeneous Poisson Processes with Shift Parameter

In this article, we study the Kolmogorov-Smirnov type goodness-of-fit test for the inhomogeneous Poisson process with the unknown translation parameter as multidimensional parameter. The basic hypothesis and the alternative are composite and carry to the intensity measure of inhomogeneous Poisson process and the intensity function is regular. For this model of shift parameter, we propose test which is asymptotically partially distribution free and consistent. We show that under null hypothesis the limit distribution of this statistic does not depend on unknown parameter.

Optimization of Extraction Process of Prunellae Spica Compound by Orthogonal Test

[Objectives] The study aimed to optimize the extraction process of Prunellae Spica compound to provide an experimental basis for the development and utilization of the compound. [Methods]Through orthogonal test,the optimal extraction process of Prunellae Spica compound was chosen by using the yield of dry paste and ursolic acid content as evaluation indicators. [Results]The optimal extraction process of Prunellae Spica compound is as follows: solvent dosage was 16 times,and extraction frequency was 3 times,while extraction time was 1 h.[Conclusions]The extraction process of Prunellae Spica compound was stable and feasible,and this study can provide a theoretical basis for further preparation of the compound.

Δ<i>I_DDQ</i>Testing of a CMOS Digital-to-Analog Converter Considering Process Variation Effects

In this paper, we present the implementation of a built-in current sensor (BICS) which takes into account the increased background current of defect-free circuits and the effects of process variation on ΔIDDQ testing of CMOS data converters. A 12-bit digital-to-analog converter (DAC) is designed as the circuit under test (CUT). The BICS uses frequency as the output for fault detection in CUT. A fault is detected if it causes the output frequency to deviate more than ±10% from the reference frequency. The output frequencies of the BICS for various (MOSIS) model parameters are simulated to check for the effect of process variation on the frequency deviation. A set of eight faults simulating manufacturing defects in CMOS data converters are injected using fault-injection transistors and tested successfully.

大截面变化率铝合金异形管整体液力成形工艺设计与优化

目的针对某大截面变化率空心构件成形难的问题,采用液力成形的方法进行成形并对其生产工艺进行优化。方法首先针对目标零件,通过压扁截面处对称及圆截面处对称2种不同的对称方式设计了A型结构和B型结构,通过有限元模拟对比了同一加载路径下2种不同结构的成形特点,选取了成形效果较好的A型结构进行成形工艺研究,建立了A型结构的成形分区图,继而根据成形分区图进行了正交试验设计。结果在同一种加载路径下,A型结构成形的目标零件最大减薄率明显小于B型结构成形的目标零件最大减薄率,且在成形过程中,B型结构压扁特征处易出现褶皱或起皱趋势,而A型结构压扁特征处壁厚分布更加均匀,A型结构成形效果优于B型结构成形效果。优化后的工艺参数如下:压制压力为2 MPa、初始压力为7 MPa、成形压力为15 MPa、轴向进给为13 mm,成形零件最大减薄率为15.9%。结论经成形分区图指导设计的正交成形试验结果均符合设计要求,成形分区图的设立对成形试验的设计具有指导作用;采用优化后的工艺参数获得了较好的试验效果,可为工业生产提供指导。

A Recursive Method of Time-Frequency Analysis for the Signal Processing of Flutter Test with Progression Variable Speed

Focused on the non-statlonarity and real-time analysis of signal in flutter test with progression variable speed （FTPVS）, a new method of recursive time-frequency analysis is presented. The time-varying system is tracked on-line by building a time-varying parameter model, and then the relevant parameter spectrum can be obtained. The feasibility and advantages of the method are examined by digital simulation. The results of FTPVS at low-speed wind-tunnel promise the engineering application perspective of the method.

基于低浓铀燃料医用同位素试验堆的99Mo分离工艺研究

医用同位素试验堆是以硝酸铀酰溶液为燃料,生产99Mo具有一定优势,已成为医用同位素生产的重要方法。低浓铀燃料是研究堆发展的趋势,在低浓铀条件下医用同位素试验堆的99Mo分离工艺至关重要。本研究主要对低浓铀燃料的医用同位素试验堆99Mo分离进行深入研究,结果显示,联合使用球形氧化铝柱、α-安息香肟柱和活性炭柱工艺,能够实现99Mo提取、分离和纯化。此外,使用该工艺在低浓铀模拟燃料溶液中对Mo的分离效果进行验证,得到Mo回收率为75.7%,杂质也满足要求。该工艺不仅提高了医用同位素试验堆在低浓铀燃料条件下99Mo的产率,更为医用同位素试验堆的低浓化奠定了基础,具有较大的应用价值。

Software Reliability Growth Model for Imperfect Debugging Process Considering Testing-Effort and Testing Coverage

Because of the inevitable debugging lag,imperfect debugging process is used to replace perfect debugging process in the analysis of software reliability growth model.Considering neither testing-effort nor testing coverage can describe software reliability for imperfect debugging completely,by hybridizing testing-effort with testing coverage under imperfect debugging,this paper proposes a new model named GMW-LO-ID.Under the assumption that the number of faults is proportional to the current number of detected faults,this model combines generalized modified Weibull(GMW)testing-effort function with logistic(LO)testing coverage function,and inherits GMW's amazing flexibility and LO's high fitting precision.Furthermore,the fitting accuracy and predictive power are verified by two series of experiments and we can draw a conclusion that our model fits the actual failure data better and predicts the software future behavior better than other ten traditional models,which only consider one or two points of testing-effort,testing coverage and imperfect debugging.

基于LMS Test.Lab的振动试验中断处理方法研究

当前产品振动试验中断处理方法主要依据GJB 150A和MIL-STD-810G标准,但是该标准只涉及一般性处理要求,缺乏具体的处理细节和注意事项,导致实用性降低。因此,本文针对基于LMS Test.Lab的电动振动试验系统,详细研究了振动试验中典型的中断处理方法。首先分析了LMS振动控制采集分析软件和振动台系统的组成和工作原理,然后归纳总结了振动试验常见的中断原因和通用处理方法,最后从软件异常、硬件故障和人因中断等三方面分析研究了振动试验中断处理方法,有助于指导设计和试验人员快速有效处理振动试验中断问题,缩短停机时间,降低试验风险,同时为军民产品振动环境与可靠性试验大纲制定提供了参考。

基于多指标权重综合评分和正交试验的调经养巢膏提取工艺优选

目的优选调经养巢膏的提取工艺。方法以加水倍数、提取时间、提取次数为考察因素,以阿魏酸、金丝桃苷、松果菊苷、丹酚酸B、淫羊藿苷的溶出量和出膏率为评价指标,分别采用层次分析(AHP)法、CRITIC法及AHP-CRITIC混合加权法确定各指标的权重系数,采用L_(9)(3^(4))正交试验优选提取工艺。结果优选工艺为复方中药加水煎煮3次,第1次加7倍量水室温浸泡40 min后,煎煮60 min,第2,3次各加5倍量水,煎煮50 min。3次验证试验测得浓缩液中阿魏酸、金丝桃苷、松果菊苷、丹酚酸B、淫羊藿苷的平均溶出量分别为0.0691,0.1307,0.8739,0.8645,0.2175 mg/mL,平均出膏率为40.35%,综合评分为93.35。结论优选工艺科学可行、稳定可控,可为后期调经养巢膏的开发利用提供参考。

不同来水流量下黄土堰塞坝溃口展宽历程的水槽试验研究

黄土在水流作用下容易遭受侵蚀,不同流量的来水对黄土堰塞坝的溃决过程和溃口扩展方式有显著影响。该文通过一系列水槽实验,流量分别为0.6 L/s、0.8 L/s、1.0 L/s、1.2 L/s和1.5 L/s,得到以下结论:①当来水流量Q≤1.0 L/s时溃口展宽为短暂历程,经历溃口贯通一个过程;来水流量Q>1.0 L/s时溃口展宽为完整历程,经历溃口贯通、快速发展、稳定三个过程;②溃口快速发展阶段中,侵蚀深度和坡角控制着溃口两侧土体的稳定性,坝顶溃口形态以及溃决流量的变化反映侵蚀方向和强度的变化;③黄土的水敏性促进了管涌现象的出现,使得坝体内部侵蚀更为剧烈,导致溃口展宽出现短暂历程;④完整历程模式下洪水迅速强烈地冲击下游,而短暂历程模式需要持续稳定的应急措施来应对洪水风险。能够为黄土堰塞坝的溃决机理和防治措施提供参考支持。

基于损伤因子的车用铰链轧制工艺优化

为了确定更适合于复杂断面型钢轧制成形工艺的韧性断裂准则,本文构建了包含韧性断裂准则的铰链型钢全轧程数值模型。通过分析轧件截面维氏硬度值与模拟计算的损伤因子之间的关系,确定了更适合在铰链型钢轧制成形工艺中应用的韧性断裂准则。研究结果表明,Brozzo韧性断裂准则在预测复杂断面型钢轧制过程中材料损伤演化方面表现最佳。此外,基于Brozzo准则计算的损伤因子,探究了不同轧制工艺参数组合对轧件最大损伤因子的影响规律。通过正交试验和多元回归分析,确定了影响轧件最大损伤因子显著的工艺参数依次为初轧温度、孔型偏转角和轧辊直径,而轧制速度的影响不显著。最终优化的工艺参数组合为:初轧温度1250℃,轧辊直径比1.15,孔型偏转角1.61°,轧辊转速148.9 r/min,此时轧件的最大损伤因子为7.92,相比于优化前减小了约20%。由此可见,选择适宜的工艺参数组合可以显著降低轧件的损伤因子,从而有效提高轧件质量。

商洛香菇和羊肚菌多糖提取工艺探究

[目的]探索商洛香菇和羊肚菌中多糖的提取工艺。[方法]以商南县香菇和羊肚菌为原料,采用超声波辅助热水浸提法对多糖进行提取。通过单因素试验,对比料液比、超声时间、超声温度和热水浸提温度对香菇和羊肚菌多糖提取率的影响,借助正交试验,得出超声波辅助热水浸提法提取香菇和羊肚菌多糖的最佳提取工艺。[结果]在料液比1∶60,超声时间30 min,超声温度40℃,浸提温度60℃的条件下,香菇多糖提取率最高;在料液比1∶50,超声时间20 min,超声温度40℃,浸提温度50℃的条件下,羊肚菌多糖提取率最高。[结论]超声波辅助热水浸提法提取香菇和羊肚菌多糖是一种可行有效、节约、经济的提取方法。

金桔红茶酒的研制及其体外抗氧化研究

以金桔(Fortunella margarita)与红茶为原料,酿酒酵母(Saccharomyces cerevisiae)SY为菌种,研制兼具金桔和红茶风味与营养的金桔红茶酒。以感官评分、酒精度及残糖量为评价指标,采用单因素试验和响应面试验优化金桔红茶酒的发酵工艺,并对其基本理化及微生物指标、功能性成分及体外抗氧化能力进行测定。结果表明,金桔红茶酒的最佳发酵工艺参数为:红茶汤与金桔汁体积比2∶1、酿酒酵母SY接种量0.3%、初始糖度23°Bx,在此条件下,金桔红茶酒的感官评分为88.62分,酒精度为11.83%vol、残糖量为9.07°Bx、pH值为3.26、总黄酮含量为0.71 mg/m L、总多酚含量为0.25 mg/m L;菌落总数和大肠杆菌(Escherichia coli)未检出,其理化和微生物指标均符合相关标准要求。金桔红茶酒的羟基自由基清除率为84.45%,1,1-二苯基-2-苦肼基(DPPH)自由基清除率为92.14%,表明其具有一定的抗氧化活性。

棉/涤混纺四面弹印花面料的生产工艺

为丰富棉/涤面料的多样性,文章对棉/涤混纺四面弹印花面料的生产工艺进行优化,最终确定了各道工序的生产工艺条件,不仅缩短了工艺流程,还保证了经向弹性。在该条件下生产的棉/涤混纺四面弹印花面料成品的尺寸稳定性、弹性性能、强力以及色牢度等各项指标均满足标准要求。