Modified DS np Chart Using Generalized Multiple Dependent State Sampling under Time Truncated Life Test

This study presents the design of a modified attributed control chart based on a double sampling(DS)np chart applied in combination with generalized multiple dependent state(GMDS)sampling to monitor the mean life of the product based on the time truncated life test employing theWeibull distribution.The control chart developed supports the examination of the mean lifespan variation for a particular product in the process of manufacturing.Three control limit levels are used:the warning control limit,inner control limit,and outer control limit.Together,they enhance the capability for variation detection.A genetic algorithm can be used for optimization during the in-control process,whereby the optimal parameters can be established for the proposed control chart.The control chart performance is assessed using the average run length,while the influence of the model parameters upon the control chart solution is assessed via sensitivity analysis based on an orthogonal experimental design withmultiple linear regression.A comparative study was conducted based on the out-of-control average run length,in which the developed control chart offered greater sensitivity in the detection of process shifts while making use of smaller samples on average than is the case for existing control charts.Finally,to exhibit the utility of the developed control chart,this paper presents its application using simulated data with parameters drawn from the real set of data.

Safety of the express freight train running over a long-span bridge

Purpose-Express freight transportation is in rapid development currently.Owing to the higher speed of express freight train,the deformation of the bridge deck worsens the railway line condition under the action of wind and train moving load when the train runs over a long-span bridge.Besides,the blunt car body of vehicle has poor aerodynamic characteristics,bringing a greater challenge on the running stability in the crosswind.Design/methodology/approach-In this study,the aerodynamic force coefficients of express freight vehicles on the bridge are measured by scale model wind tunnel test.The dynamic model of the train-long-span steel truss bridge coupling system is established,and the dynamic response as well as the running safety of vehicle are evaluated.Findings-The results show that wind speed has a significant influence on running safety,which is mainly reflected in the over-limitation of wheel unloading rate.The wind speed limit decreases with train speed,and it reduces to 18.83 m/s when the train speed is 160 km/h.Originality/value-This study deepens the theoretical understanding of the interaction between vehicles and bridges and proposes new methods for analyzing similar engineering problems.It also provides a new theoretical basis for the safety assessment of express freight trains.

归来庄金矿矿体和岩体中Au等成分的Runs检验及意义

Runs检验是研究序列分布规律的一种数学方法。用这种方法检验归来庄金矿和铜石杂岩体的某些成分,得出归来庄金矿TC30中Au的高品位值的出现不是随机的,而是具有集中出现的规律性;铜石杂岩体中SiO2和Au都是具有随机变化性,说明杂岩体没有明显的演化关系,不同岩体的形成时间先后对成矿元素Au的富集没有明显影响;杂岩体中Al2O3和TiO2比值在闪长玢岩和二长斑岩中无明显差异,说明二者为同源成因。

Beep test评估11～15岁少年游泳运动员有氧能力的效度研究

目的:评估现有通过beep test估算VO_2max的公式在我国少年游泳运动员中的适用性,以及能否建立预测准确性更高的公式。斱法:28名男子和25名女子少年游泳运动员,年龄11~15岁,先进行beep test获得最快折返跑速度,随后通过递增负荷跑台测试获得VO_2max测试值。通过逐步回归法建立新的VO_2max估算公式,计算分别通过Léger、Barnett(a)、Barnett(b)、Matsuzaka和新公式的VO_2max估算值,采用差值比较、相关分析、误差分析和一致性分析进行各估算值的效度检验。结果:1)通过Léger、Barnett(a)、Barnett(b)和Matsuzaka公式得出的VO_2max估算值均显著低于测试值,%Error为(68.4~90.0)%,与测试值间的差值为7.63~9.02ml/kg/min,一致性界限为0.49~17.55 ml/kg/min。2)VO_2max的新预测公式为VO_2max=61.435+3.211S-2.003BMI-5.189×G(r=0.715,P=0.004,SEE=2.25 ml/kg/min),其中G表示性别(男=0,女=1),S为最快折返跑速度。3)新公式得出的VO_2max估算值与测试值无显著差异,%Error下降至16.1%,与测试值间的差值减少到0.02±3.09 ml/kg/min,一致性界限为-6.03~6.08 ml/kg/min。结论:beep test适用于我国少年游泳运动员有氧能力的评估,但现有VO_2max估算公式的效度水平一般。基于本研究所选取群体新建的估算公式有效提高了预测的准确性。

Geomechanical properties will constrain CO_(2)injection into the lower Ordovician Rose Run sandstone deep saline reservoir,Appalachian Basin,Kentucky,USA

The Kentucky Geological Survey(KGS)1 Hanson Aggregates stratigraphic research well,Carter County,Kentucky,USA,was drilled to a total depth of 1474 m as a field-scale test of potential CO2 storage reservoir properties in the Central Appalachian Basin.Geomechanical properties of the Rose Run sandstone(upper Ordovician Knox group)were tested for its suitability as a storage reservoir.A 9.8-m thick section of the Rose Run was penetrated at 1000 m drilled depth and a whole-diameter core and rotary sidewall cores were taken.Average porosity and permeability measured in core plugs were 9.1%and 44.6 mD,respectively.Maximum vertical stress gradient calculated in the wellbore was 26 MPa/km.Wellbore fractures in dolomites underlying and overlying the Rose Run follow the contemporary N53E Appalachian Basin stress field.The Rose Run elastic geomechanical properties were calibrated to values measured in core plugs to evaluate its fracturing risk as a CO2 storage reservoir.Mean Young’s modulus and Poisson’s ratio values of the Rose Run were 45 GPa and 0.23,respectively,whereas Young’s modulus and Poisson’s ratio values were 77.1 GPa and 0.28,respectively,in the overlying Beekmantown dolomite,suggesting the Rose Run may fracture if overpressured during CO2 injection but be confined by the Beekmantown.Triaxial compressive strength measured in core plugs found the Rose Run and Beekmantown fractured at mean axial stresses of 156.5 MPa and 282.2 MPa,respectively,confirming the Beekmantown as suitable for confining CO2 injected into the Rose Run.A step-rate test was conducted in a mechanically-isolated 18.6-m interval bracketing the Rose Run.Static Rose Run reservoir pressure was 9.3 MPa,and fracture gradient under injection was 13.6 MPa/km,suggesting step-rate testing before CO2 injection,and subsequent pressure monitoring to ensure confinement.As the region around the KGS 1 Hanson Aggregates well is underpressured and adjacent to faulted Precambrian basement,further research is needed to evaluate its induced seismicity risk during CO2 injection.

Dynamic Crowd Loading Test on Tibetan Ancient Structures

The field test of a typical Tibetan ancient structure instrumented with displacement and acceleration transducers was conducted to measure time histories due to crowd walking and running. The test case is introduced firstly. The displacement time histories are then used to analyze the dynamic property such as fundamental frequency of vertical vibration and damping ratio of the test structure, and the acceleration time histories are applied to evaluate the floor vibration serviceability. The floor interaction and comparison of human walking and running are also discussed. Some valuable conclusions are given.

CORE-UNIFIED SOC TEST DATA COMPRESSION AND APPLICATION

The pattern run-length coding test data compression approach is extended by introducing don't care bit(x) propagation strategy into it.More than one core test sets for testing core-based System-on-Chip(SoC) are unified into a single one,which is compressed by the extended coding technique.A reconfigurable scan test application mechanism is presented,in which test data for multiple cores are scanned and captured jointly to make SoC test application more efficient with low hardware overhead added.The proposed union test technique is applied to an academic SoC embedded by six large ISCAS'89 benchmarks,and to an ITC' 02 benchmark circuit.Experiment results show that compared with the existing schemes in which a core test set is compressed and applied independently of other cores,the proposed scheme can not only improve test data compression/decompression,but also reduce the redundant shift and capture cycles during scan testing,decreasing SoC test application time effectively.

针刺诱发电池热失控的研究进展综述

针刺测试是研究锂离子电池热失效机理和热失控特性的重要方法之一。本文汇总了目前广泛采用的针刺测试设置,并研究了不同变量对热失控演化的影响,包括针刺的深度、速度、位置以及针的材料和直径等,对针刺破坏下锂离子电池内短路及热失控行为进行机理性探索与分析。结果发现,针刺的深度与电池热失控行为的严重程度成正比,针刺的速度对电池热失控没有明显影响,针刺发生在活性材料较密集或电极附近时电池热失控更严重。针的材料和直径对电池热失控行为具有双重影响,需要结合实际情况对产热和散热情况分别进行分析。最后通过总结不同因素对电池热失控的影响,对减缓锂离子电池热失控以及更新其安全测试程序提出了新的见解,为后续的创新型研究工作提供思路。

下陡上缓混合式海堤上不规则波爬高研究

波浪爬高是影响海堤堤顶高程的一个重要因素,直接影响工程投资。下部为陡墙、上部为斜坡、中间带平台的海堤为我国沿海常见的一种海堤断面型式,为研究此种海堤断面型式上不规则波爬高规律,通过物理模型试验观测得到不同试验条件下波浪爬高,并根据海堤下部陡墙坡度、上部斜坡坡度、平台宽度与平台高度、波浪要素对波浪爬高的影响分析,拟合了不规则波爬高计算公式。结果表明,陡墙坡度为0的海堤的波浪爬高值比0.5小;当波陡在0.03~0.05之间时,随着海堤上部坡度变缓,大部分波浪爬高逐渐减小;波浪爬高随着平台宽度的增加而减小;波浪爬高随着海堤平台位置的降低而增大;波浪爬高随着波陡的增加呈现先增大后减小的趋势;拟合公式可反映下部为陡墙、中间为平台、上部为斜坡的混合式海堤断面上波浪爬高规律。

A Novel Variable Shifting Code for Test Compression of SoC

The test vector compression is a key technique to reduce IC test time and cost since the explosion of the test data of system on chip （SoC） in recent years. To reduce the bandwidth requirement between the automatic test equipment （ATE） and the CUT （circuit under test） effectively, a novel VSPTIDR （variable shifting prefix-tail identifier reverse） code for test stimulus data compression is designed. The encoding scheme is defined and analyzed in detail, and the decoder is presented and discussed. While the probability of 0 bits in the test set is greater than 0.92, the compression ratio from VSPTIDR code is better than the frequency-directed run-length （FDR） code, which can be proved by theoretical analysis and experiments. And the on-chip area overhead of VSPTIDR decoder is about 15.75 % less than the FDR decoder.

Diagnostic values of combination of free running asthma screening test and total serum allergen IgE level in children with asthma

Background A free running asthma screening test is usually used for screening exercise-induced bronchoconstriction.The total serum allergen IgE level can reveal the patient＇s atopy characteristics.Our study is to evaluate the diagnostic values of the combination of the two tests in asthmatic children and compare this new diagnostic method with the Intemational Study of Asthma and Allergies in Childhood （ISSAC） questionnaires and the bronchial provocation test,which are popular diagnostic tool for pediatric asthma.Methods A total of 773 school children were recruited in this study.The children＇s asthma was diagnosed by means of a combination of the free running asthma screening test and total serum allergen IgE level.The new diagnostic method value was assessed using receiver operating characteristic （ROC） curves and compared with other diagnostic tools such as ISSAC questionnaires and the bronchial provocation test.Results The AUC of this new diagnostic method was higher than 0.9.When the cut-off value of total serum allergen IgE level was ≥47 KU/L,the sensitivity and the specificity were 71.4％ and 85.1％,respectively,which were better than those of either the ISSAC questionnaires or bronchial provocation test.Conclusion The combination of the free running asthma screening test and total serum allergen IgE level may be an effective diagnostic tool for children＇s asthma.

我国重载铁路技术规章管理现状及问题初探

随着重载铁路的发展,越来越多的铁路局集团公司管内开通运行了重载列车。由于重载铁路在技术设备和运营管理等方面的特点,既有普速铁路技术管理无法满足重载铁路的运用需求。相关铁路局集团公司在不同程度上制定了关于重载铁路的技术规章,但是国铁集团层级仍缺少关于重载铁路的基础性、系统性技术规章,基于国铁集团、铁路局集团公司层级的重载铁路技术管理现状,对重载铁路技术规章编制中可能遇到的若干关键技术管理问题进行了研究分析,为后续开展国铁集团层级重载铁路技术规章的制定具有一定的借鉴意义。

一种改进的智能长跑测试系统设计与实现

基于西南财经大学天府学院第一代产品设计了一种改进的智能长跑测试系统。首先,采用高精度天线采集RFID信号,通过2.4G无线通信技术实现超高频读写器与智能应用之间的交互。其次,优化长跑数据解析算法,利用数据帧关联性最大限度地解析长跑数据,并实时展示测试结果。此外,增加了RFID预检环节,检查RFID卡片是否正常工作,及时排除无法识别的卡片。实验结果表明该系统具有更好的精确性和稳定性。

人工智能机器人视觉识别系统设计

随着人工智能技术的飞速发展,机器人视觉识别系统在工业、医疗、安防等领域发挥着越来越重要的作用。文章设计了一个基于人工智能的机器人视觉识别系统,包括对象检测、图像分类、人脸识别、目标跟踪和图像增强等功能。经测试,验证了系统的稳定性和可靠性。该系统可应用于多个领域,具有广阔的发展前景。

网球比赛的走势预测

以2023年温布尔登网球锦标赛的比赛数据为例,利用因子分析和逻辑回归方法刻画了球员“状态”的变化并预测网球比赛的走势。首先,确定9个评价指标,运用主成分分析法从中提取出4个共性因子,实现了球员“状态”的可视化;其次,采用游程检验方法检验比赛的随机性,证明球员“状态”决定了比赛的走势;最后,对“关键点”数据集进行斯皮尔曼相关分析,并运用逐步剔除回归分析法构建模型,预测比赛走势。

电力机车走行风相变散热器风洞试验研究

文章基于电力机车走行风相变散热器的结构模型,建立了其等效热阻网络,分析其传热特性,推导了风速影响下散热量的修正系数关系式;通过风洞试验,研究了散热器在不同风速、不同水流量下散热量和热阻的变化特性,以及散热器在不同风速下的热启动性能及阻力特性。结果表明:散热器散热量随风速及水流量的增大而不断增大,而散热器热阻则刚好相反;散热器静态启动时间和散热启动时间均小于4 min;单个散热器产生阻力仅为机车牵引力的0.17‰,对整车阻力影响很小。

辊压机减速机空负荷试车工艺设计

针对辊压机减速机在维修装配完毕后,受自身外形结构和固定位置的限制,无法实现空负荷试车或无法满转速试车的问题,对辊压机减速机空负荷试车工艺进行改进设计,改进后的新工艺解决了原试车过车中存在的问题。

水翼船的横摇控制

将一条模型尺度的全浸没式水翼艇作为案例船开展横摇控制研究。采用模型预测控制算法有效处理水翼失速角等约束条件,同时限制水翼的大幅剧烈运动,兼顾横摇姿态控制和执行机构保护的双重目标。在预测模型中增添预测偏差量作为前馈项,用以消除稳态误差,对常规模型预测控制算法做出一个重要改进。将案例船配备推进系统和可控水翼进行横摇控制航行试验,结果清晰展示了改进型模型预测控制器的横摇控制效果,这对水翼船的姿态控制研究具有重要借鉴意义。

矿用带式输送机运行阻力的应用分析

带式输送机是煤矿开采中常用的输送设备,随着煤矿长距离、大运量的输送,带式输送机的能耗成为研究的重点。针对带式输送机的运行阻力进行分析,搭建了阻力测试系统,在不同的运行载荷、速度及温度作用下,对带式输送机的运行阻力进行分析,得到不同因素的影响作用,从而为带式输送机的使用提供指导,降低带式输送机的能耗。

中深层无干扰地岩热供暖系统测试研究

地热能被誉为面向未来的能源,在我国“双碳战略”背景下其开发利用受到越来越多重视。中深层无干扰地岩热供暖技术具有“封闭换热、对地上地下环境无干扰、自主供热”等特点,近年来已在我国很多地区得到应用。进一步探究该技术在不同地区的应用特点,对中深层无干扰地岩热技术在宁夏地区的首个应用案例进行测试研究。经测试单口中深层无干扰地岩热换热孔平均输出功率为547.9 kW,连续测试四个月期间热源侧平均供水温度变化范围为33.622.7℃,没有明显的下降;经测试数据分析计算,应用案例年运行成本135662.6元,平均运行单价为1.71元/m^(2)·月;相比于燃煤锅炉供暖方式,年可节约费用517937.4万元,运行单价降低6.53元/m^(2)月,降低幅度达79%;同时年可替代标煤116.3 t,年可减少CO_(2)排放量为288.1 t,具有良好的经济和环保效益。