Aging effect and test-retest reliability of the sinusoidal harmonic acceleration test and velocity step test using nanotorque rotatory chair

Introduction:Rotatory chair testing has been used to evaluate horizontal canal function.Frequently used tests include sinusoidal harmonic acceleration test(SHAT)and velocity step test(VST).Objectives:Assessment of age effect on the SHAT and VST and assessment of test-retest reliability of the parameters of those two tests.Methods:A prospective study was performed on 100 subjects with no ear or vestibular complaints and normal vestibular evaluation.They were divided into two groups;Group A:below 50 years of age and Group B:50 years of age or above.SHAT was presented at frequencies 0.02,0.04,0.08,0.16,0.32,0.64 Hz with a peak velocity of 60°/s.VST was performed using a maximum velocity of 100°/s with acceleration and deceleration of 200°/s2.Thirty subjects were tested twice to assess reliability.Results:Study participants ranged in age from 20 to 67 years.Regarding group A,the mean age was30.92±7.31 and 55.36±4.61 for group B.No significant differences were found in SHAT parameters between the two groups.As well,there was no significant difference in VST per-rotatory time constant,however,post-rotatory time constant was significantly longer for Group B(P value<0.05).Intraclass correlation coefficient(ICC)values showed moderate to good reliability(ICC 0.5800.818)for SHAT parameters for the lower frequencies and indicated moderate reliability for VST time constant(ICC 0.5090.652).Conclusions:Age has no significant effect on the parameters of SHAT and VST.Test-retest reliability is generally good for both tests.

Comparison of Procedures to Evaluate the Cyclic Stress-Strain Curve from Incremental Step Test

The design of structural components in low-cycle fatigue field often requires the knowledge of the cyclic properties of the material, which are commonly described by the classical relation of Ramberg-Osgood. In order to obtain the cyclic curve using experimental data from incremental step tests, four methodologies are described and critically discussed. Three methods differ in the procedure of evaluation of the elastic modulus, while in the last one the experimental data are interpolated with a single non-linear regression. The various techniques were applied to data obtained from tests carried out on stainless steel specimens, and the resulting differences were analysed and quantified. An average behaviour was evaluated considering the total set of data obtained from experimental tests. The choice of the most suitable method is related to both the strain range of interest and the goal for which the results are used.

Validation of a 2 Minute Step Test for Assessing Functional Improvement

Introduction: Although many cardiopulmonary patients require home care services, the 6-minute walk test (6MWT) is unusable in most dwellings for objectively evaluating exercise capacity because it requires a 20 - 30 meter hallway. To meet this need, we developed a 2-minute step test (2MST): stepping up and down an 8 inch step for 2 minutes (1 step = bilateral step up + step down). Purpose: Evaluate the statistical validity, reproducibility, and sensitivity of the 2MST in assessing exercise capacity. Method: We compared the heart rate, oxygen saturation and perceived exertion obtained during performance of 2MST with those obtained during the 6MWT. Results: Comparing 2MST and 6MWT in 158 subjects for validity, r = 0.925 (P Conclusion: The 2MST is valid, reproducible, sensitive, safe, well-tolerated, and is a suitable substitute for the 6MWT.

CMT Cycle Step工艺参数对焊缝表面特征纹路及成形尺寸的影响

采用CMT Cycle Step焊接工艺进行平板堆焊正交试验,研究了送丝速度、焊接速度、熔滴数量和间隔时间四个参数对焊缝表面特征纹路及成形尺寸的影响,建立了各参数与焊缝表面鱼鳞纹步长S、焊缝熔宽B、堆焊层厚度h之间的回归模型.结果表明,随着焊接速度、熔滴数量和间隔时间的增大,焊缝表面鱼鳞纹步长S呈逐渐增大的趋势.适当减小焊接速度和间隔时间,可有效减小焊缝表面高度差Δh,提高焊缝表面成形质量.随着送丝速度和熔滴数量的增大,焊缝熔宽B和堆焊层厚度h均逐渐增大;随着焊接速度的增大,焊缝熔宽B和堆焊层厚度h逐渐减小.根据理论分析和回归分析得到准确性较高的回归方程,为预测焊接焊缝成形以及优化焊接工艺参数提供理论依据.创新点:(1)系统研究了CMT Cycle Step焊接工艺参数对焊缝成形的影响规律,有助于采用该方法解决点焊、热敏感材料焊接、电弧增材制造等领域的相关技术难题.(2)建立了CMT Cycle Step焊接工艺的送丝速度、焊接速度、熔滴数量和间隔时间四个参数对焊缝表面特征纹路及成形尺寸回归模型,为预测焊缝成形以及优化焊接工艺参数提供理论依据.(3)对CMT Cycle Step焊缝表面特征纹路—鱼鳞纹进行量化评价,探究工艺参数对焊缝表面鱼鳞纹步长S和表面高度差Δh的影响规律,有利于获得高表面平整度的焊缝.

Detonator stepping stress acceleration life test

Through the failure mechanism analysi s and simulation test of a certain kind of detonator,this paper confirms the str ess level of the stepping stress acceleration life test of the detonator,and t hen e stablishes the data processing mathematical model and storage life forecasting m ethod.At last,according to the result of the stepping stress acceleration lif e test of the detonator,this paper forecasts the reliable storage life of the detonator under the normal stress level.

Inference and optimal design on step-stress partially accelerated life test for hybrid system with masked data

Under Type-Ⅱ progressively hybrid censoring, this paper discusses statistical inference and optimal design on stepstress partially accelerated life test for hybrid system in presence of masked data. It is assumed that the lifetime of the component in hybrid systems follows independent and identical modified Weibull distributions. The maximum likelihood estimations(MLEs)of the unknown parameters, acceleration factor and reliability indexes are derived by using the Newton-Raphson algorithm. The asymptotic variance-covariance matrix and the approximate confidence intervals are obtained based on normal approximation to the asymptotic distribution of MLEs of model parameters. Moreover,two bootstrap confidence intervals are constructed by using the parametric bootstrap method. The optimal time of changing stress levels is determined under D-optimality and A-optimality criteria.Finally, the Monte Carlo simulation study is carried out to illustrate the proposed procedures.

月球弹簧回复式绳驱采样机械臂的设计及试验

针对深低温、低重力环境的月壤采样任务,设计并研制了一种功耗低、重量轻、结构简单、可靠性高的四自由度绳驱机械臂。将驱动绳索安装在臂杆末端,较大程度地减小了机械臂的功耗;在关节2、3处安装扭转弹簧,通过弹簧扭力给机械臂末端提供超过20 N的下压力;针对深低温环境,匹配了不同材料的配合间隙,提高了机械臂的可靠性;建立并验证了机械臂运动学模型的正确性。采样路径的仿真结果表明机械臂可完成采样任务。采用半闭环控制策略对样机的各独立关节进行了位置阶跃试验和正弦轨迹跟踪试验,试验结果表明各关节具备较高的响应速度、良好的稳定性和轨迹跟踪能力。

文冠果油对雄性小鼠记忆能力的影响

为了对文冠果油相关产品的开发提供数据支撑,将健康雄性小鼠分为4个组,即对照组(玉米油)、文冠果油低剂量组〔2.1 g/(kg·d)〕、文冠果油中剂量组〔4.2 g/(kg·d)〕和文冠果油高剂量组〔12.5 g/(kg·d)〕,分别经口给予小鼠灌胃1个月后,测定小鼠体质量,并进行跳台试验、避暗试验、水迷宫试验以评价文冠果油对雄性小鼠记忆能力的影响,试验结束后测定小鼠海马和大脑皮质组织匀浆中多巴胺(DA)、5-羟色胺(5-HT)、去甲肾上腺素(NE)、乙酰胆碱(ACh)含量及乙酰胆碱酯酶(AChE)活性,探讨文冠果油对小鼠记忆能力的影响机制。结果表明:经过1个月的灌胃试验,各组小鼠体质量及其增长率均无显著差异;文冠果油组小鼠跳台试验、避暗试验、水迷宫试验均为阳性;文冠果油高剂量组小鼠海马和大脑皮质组织匀桨中5-HT、ACh、NE、DA含量明显升高,AChE活性明显降低。综上,文冠果油具有改善小鼠记忆的功能,且是通过改善单胺类神经递质和胆碱能神经递质的代谢发挥作用的。

Shaking table comparative test and associated study of a stepped wall-frame structure

A new structural system called a stepped wall-frame structure is proposed in this study to solve the bottom yielding problem of RC frames, which widely occurred during previous earthquakes such as thc Wcnchuan and Yushu earthquakes in China. A 1/5 scale ordinary RC frame model and a stepped wall-frame model were subjected to shake table motions together to study the seismic behavior of the new structural system. This paper presents the dynamic characteristics, the seismic responses and the failure and collapse mechanism of the two models under low, moderate and high intensity shaking. The test results and further analysis demonstrate that the seismic performance of stepped wall-frame structures is superior to ordinary RC frames in terms of the well-controlled deformation pattern and more uniformly distributed damage. The stepped wall can effectively suppress the bottom yielding mechanism, and is simple, economical and practical tbr engineering practice.

证人出庭“三要件”的法教义学解读

通说认为,证人出庭“三要件”中“法院认为有必要出庭作证”为决定性要件。该观点符合当前绝大多数案件法院均以“无必要”为由限制证人出庭的司法现状。然而根据立法原意,证人出庭“三要件”处于平行、独立地位,不得以“有必要”为决定要件而忽略了对前两个要件的判断。在坚守“证人出庭为原则”基本立场基础上,以“三步检验法”重新构建证人出庭审查内容:第一,“控辩双方有异议”注意提出异议时间、异议方式以及异议主体;第二,“证人证言对定罪量刑有重大影响”应当从证人证言所蕴含的“待证事实”内容出发,由申请方承担初步证明,法院履行“无重大影响”说理义务;第三,法院认为“无必要”出庭仅限于明显重复、合理预断以及证人基于特殊原因无法出庭三种情形。

Selection of time step for pseudodynamic testing

Although the step degree of nonlinearity has been introduced to conduct basic analysis and error propagation analysis for the pseudodynamic testing of nonlinear systems, it cannot be reliably used to select an appropriate time step before performing a pseudodynamic test. Therefore, a novel parameter of instantaneous degree of nonlinearity is introduced to monitor the stiffness change at the end of a time step, and can thus be used to evaluate numerical and error propagation properties for nonlinear systems. Based on these properties, it is possible to select an appropriate time step to conduct a pseudodynamic test in advance. This possibility is very important in pseudodynamic testing, since the use of an arbitrary time step might lead to unreliable results or even destroy the test specimen. In this paper, guidelines are proposed for choosing an appropriate time step for accurate integration of nonlinear systems. These guidelines require estimation of the maximum instantaneous degree of nonlinearity and the solution of the initial natural frequency. The Newmark explicit method is chosen for this study. All the analytical results and the guidelines proposed are thoroughly confirmed with numerical examples.

渐扩式台阶泄洪道消能特性及优化研究

台阶式泄洪道的结构设计和消能问题一直是台阶式泄洪道工程设计的重点.在实际工作中,通过物理模型试验和数值模拟的方法来进行结构形式和消能率的优化研究.本文通过物理模型试验,对长阳土家族自治县枝柘河流域防洪治理工程中的高陡坡渐扩式台阶泄洪道水力学特性进行了试验研究,并对其结构进行了优化设计.研究表明,本工程中渐扩式台阶泄洪道总体结构设计新颖合理,但存在转弯段结构设计问题.经过优化设计后,泄洪道水流流态良好,在设计工况时消能率达98%,达到预期消能目的.

速度阶跃试验的新认知

速度阶跃试验(velocity step test,VST)是一种评估前庭功能的旋转试验,能够反映水平半规管前庭眼反射功能和速度存储机制。我们对VST的机制、检查方法、临床表现及影响因素进行了综述。在VST中,衰减时间常数(time constant,Tc)与峰值增益是两个主要参数,较短的Tc常见于单侧或双侧外周病变,而较长的Tc可能与中枢处理缺陷有关。虽然峰值增益重要性略逊于Tc,但其可以为Tc提供补充信息。Tc与正弦谐波加速试验的相位可进行换算,这两种方法可在临床上互为补充。在实际应用中,Tc会受到检查顺序、转椅速度、头部位置、适应性和警觉性、乙醇作用和视觉条件等因素的影响。目前,VST在前庭领域的研究主要限于描述前庭双温和晕动症的表现,对于其在其他领域的应用,仍需要进一步的研究。

Guideline of Test Suite Construction for GUI Software Centered on Grey-Box Approach

In this paper, the test suite construction for GUI (Graphical User Interface) software may be executed centered on grey-box approach with the prior test design of window access controls for unit testing, including front-end method of white box and follow-up black box method for integration testing. Moreover, two key opinions are proposed for the test suite construction for GUI software, the first one is that the “Triple-step method” should be used for unit testing with the prior disposing of data boundary value testing of input controls, and another one is that the “Grey-box approach” should be applied in integration testing for GUI software with necessary testing preparation in the precondition. At the same time, the testing of baseline version and the incremental testing should be considered for the test case construction to coordinate with the whole evolution of software product today. Additionally, all our opinion and thought are verified and tested with a typical case of GUI software—PQMS (Product Quality Monitoring Software/System), and results indicate that these methods and specific disposing are practical and effective.

STEP一致性测试系统的开发

STEP AP2 0 3( ISO10 30 3- 2 0 3- 1994)是表达 3D机械产品在设计阶段的产品数据的国际标准 ,它提供了一种独立于任何特定系统的信息通信的中性机制 .然而 ,如果不对应用系统进行确定其是否与标准相一致的测试 ,则产品数据交换的目标就不能完全达到 .文中在给出 STEP一致性测试的系统方法的基础上 ,通过已开发的 STEPAP2 0 3一致性测试系统 ,来说明如何实现

一种高精度快速激光修调方案设计

在激光修调过程中,激光的修调路径和控制策略是影响修调精度和修调速度的关键因素,而常规激光修调方案难以同时满足高精度和快速修调。因此,提出了一种高精度快速激光修调方案,使用“离散+连续”结构的金属薄膜电阻图形提高修调效率和可靠性;利用阶梯形的激光修调路径提升修调精度;采用动态测试步长的控制策略提高修调速度。采用上述方案对60个金属薄膜电阻样品进行激光修调,结果表明:修调精度可达0.004%,平均测试步长为2.53,验证了所提出的修调方案可有效提升修调精度和修调速度。进一步将该方案应用在200个温度传感器芯片的校准中,结果表明200个温度传感器芯片的测温误差均校准至±0.2℃以内,平均测试步长为6.29。

基于遗传BP算法预测贮存寿命

目的针对引信自然贮存试验数据统计方法计算量大且试验时间开展较长的问题,提出BP和遗传算法相结合的方法(遗传BP算法),通过步加试验解决寿命预测问题。方法通过步加试验数据求其试验各级应力下的环境因子,由环境因子将各级应力试验时间折合成实际贮存时间,根据Arrhenius模型求出可靠度函数。其次,采用遗传算法优化BP神经网络,避免陷入BP局部最优问题,将步加试验数据代入遗传BP算法进行训练,提高预测的精度和准确度。将正常应力下的数据代入遗传BP算法进行测试,求出可靠度预测值。最终对比实际、Arrhenius模型、遗传BP算法的贮存可靠度预测值。结果实际、Arrhenius模型、遗传BP算法的贮存可靠度预测值相近,证明遗传BP算法可以满足引信贮存可靠度的预测。结论采用遗传BP算法对步加试验进行寿命预测,可以有效减少试验时长和降低试验成本。

智能创作中版权豁免制度的边界与拓展

人工智能可以通过大量的数据进行训练,学习数据中的规律和特征,高效生成新的内容,这不仅引发了创作模式的改革,同时也给版权豁免制度带来了挑战。版权豁免制度设立的初衷在于平衡本权与他权。然而,随着人工智能带来的技术变革和产业调整,版权豁免制度在应对智能创作时暴露出了观念边界、规范边界以及条件边界受限等问题。对此,需要探索版权豁免制度的梯度式拓展策略,首先是主体拓展,针对“个人使用”条款的扩张解释。其次是原理拓展,将合理使用步骤化考量转向综合性考量。再次是规则拓展,增加智能创作豁免专项条款。最后是经济拓展,探索人工智能征税制度,从而保证“生动化创作”与“自动化创作”都能获得合理的规范支持与发展空间。

引信步进应力加速试验贮存寿命预测研究

目的 针对某机电引信加速寿命试验数据,采用传统统计分析方法存在计算量大、寿命预测精度难以保证的问题,开展与智能算法相结合的引信贮存寿命预测研究。方法 针对步进应力加速寿命试验数据,采用贝叶斯理论的环境因子法,对各级应力下的贮存时间进行折合计算。利用进化策略对粒子群算法进行改进,进而对所建立的BP神经网络预测模型的全局参数进行调整和优化,突破传统方法的局限。将折合后的试验时间、样本量、应力水平作为网络输入,失效数作为输出,来预测引信贮存寿命。结果 利用训练好的BP神经网络预测引信在正常应力水平下的失效数,计算其贮存可靠度。在迭代402次后,模型找到最优解,且预测误差在1%以内。结论 步进应力加速寿命试验与智能算法相结合的方法计算过程简单,预测精度较高,可有效提高引信贮存寿命的预测精度。

产前超声筛查五步检查法在胎儿心脏畸形诊断中的应用价值

目的分析产前超声筛查五步检查法在胎儿心脏畸形诊断中的应用价值。方法选取2020年1月至2021年12月我院收治的88例疑似怀有心脏畸形胎儿孕产妇为研究对象。所有研究对象均先接受常规产前超声筛查三步检查法检查,再接受产前超声筛查五步检查法检查。以分娩后新生儿心脏彩超或引产后胎儿尸检结果为金标准,比较两种检查方法的诊断效能及对不同类型胎儿心脏畸形的检出情况。结果金标准检查结果显示,88例疑似心脏畸形胎儿中,71例确诊为胎儿心脏畸形。产前超声筛查五步检查法在胎儿心脏畸形中的诊断准确度、灵敏度均高于常规产前超声筛查三步检查法(P<0.05);产前超声筛查五步检查法与常规产前超声筛查三步检查法在胎儿心脏畸形中的诊断特异度、阳性预测值、阴性预测值比较,差异无统计学意义(P>0.05)。产前超声筛查五步检查法对室间隔缺损、右心室肥大、心内膜垫缺损及心室发育不良综合征的鉴别准确率高于常规产前超声筛查三步检查法(P<0.05)。结论产前超声筛查五步检查法对胎儿心脏畸形的诊断效能较优,且能有效鉴别不同类型的胎儿心脏畸形,可作为胎儿心脏畸形的产前超声筛查手段,降低心脏畸形新生儿出生率。