Sample Size Determination and Statistical Hypothesis Testing for Core Centration in Press Coated Tablets

A novel statistical approach to evaluate the manufacturing quality of press coated tablets in terms of the centering of their core is presented. We also provide a formula to determine the necessary sample size. This approach is applied to real data.

Testing of Anti-stripping Property of Friction Spun Core Yarn

Friction spun core yarn has two components: filament core and staple fiber sheath. Under axial rubbing action, the failure mode of the core yarn is the stripping of the sheath from the core. This paper introduces a method to test the anti - stripping property of the core yarn. With a modified Universal Testing Machine, the stripping resistance of friction spun core yarn can be continuously measured. Some factors Influencing the measurements are discussed in detail. The testing results are compared with those from a Y731 Yarn Abrasion Tester and fur - ther confirmed by weaving practice.

软硬件协同的RapidIO接口带宽测试方法

RapidIO是一种高性能嵌入式系统互联技术。FPGA的SRIO控制器实现了RapidIO二代协议,在工程中经常需要得到其实际带宽性能以确定其是否满足应用需求。采用FPGA的嵌入式软核,配合FPGA内部硬件电路可搭建软硬件协同SOPC测试系统。该系统既具有硬件可裁剪、可定制、扩展性强的特点,又具备软件灵活性的特点。此系统在硬件层面设计了周期采样单元、周期配置接口、锁存接口、上传接口;软件层面具备采样参数配置、采样控制、采样数据分析、结果呈现功能。通过软硬件代码的编写和验证,表明此方法可实时监测接口的带宽及抖动性能指标。

Research on in-situ condition preserved coring and testing systems

As shallow resources are increasingly depleted,the mechanics'theory and testing technology of deep insitu rock has become urgent.Traditional coring technologies obtain rock samples without retaining the in-situ environmental conditions,leading to distortion of the measured parameters.Herein,a coring and testing systems retaining in-situ geological conditions is presented:the coring system that obtains in-situ rock samples,and the transfer and testing system that stores and analyzes the rocks under a reconstructed environment.The ICP-Coring system mainly consists of the pressure controller,active insulated core reactor and insulation layer and sealing film.The ultimate bearing strength of 100 MPa for pressurepreservation,temperature control accuracy of 0.97%for temperature-retained are realized.CH_(4)and CO permeability of the optimized sealing film are as low as 3.85 and 0.33 ppm/min.The average tensile elongation of the film is 152.4%and the light transmittance is reduced to 0%.Additionally,the pressure and steady-state temperature accuracy for reconstructing the in-situ environment of transfer and storage system up to 1%and±0.2 is achieved.The error recorded of the noncontact sensor ring made of lowdensity polymer is less than 6%than that of the contact test.The system can provide technical support for the deep in-situ rock mechanics research,improving deep resource acquisition capabilities and further clarifying deep-earth processes.

基于硬件描述语言的MP3解码器仿真平台的搭建以及IP Core的重用

开发基于硬件描述语言的 MP3解码器 ,首要的问题是要搭建一个能被很好地掌握控制的仿真平台。仿真平台包括仿真输入平台和仿真输出平台。在仿真输入平台中 ,构造了 2个模块 ,一个是用来存储 MP3音频文件的 ROM模块 ,另一个是控制器模块 ,其功能是把 RO M中的数据以串行数据流的方式送到解码器模块中去。其中 ,在构造 RO M模块时 ,采用了 IP

Development of a Drilling and Coring Test-bed for Lunar Subsurface Exploration and Preliminary Experiments

Drill sampling has been widely employed as an effective way to acquire deep samples in extraterrestrial exploration. A novel sampling method, namely, flexible-tube coring, was adopted for the Chang＇e mission to acquire drilling cores without damaging stratification information. Since the extraterrestrial environment is uncertain and different from the terrestrial environment, automated drill sampling missions are at risk of failure. The principles of drilling and coring for the lunar subsurface should be fully tested and verified on earth before launch. This paper proposes a test-bed for conducting the aforementioned experiments on earth. The test-bed comprises a rotary-percussive drilling mechanism, penetrating mechanism, drilling medium container, and signal acquisition and control system. For granular soil, coring experiments indicate that the sampling method has a high coring rate greater than 80%. For hard rock, drilling experiments indicate that the percussive frequency greatly affects the drilling efficiency. A multi-layered simulant composed of granular soil and hard rock is built to test the adaptability of drilling and coring. To tackle complex drilling media, an intelligent drilling strategy based on online recognition is proposed to improve the adaptability of the sampling drill. The primary features of this research are the proposal of a scheme for drilling and coring a test-bed for validation on earth and the execution of drilling experiments in complex media.

Ant colony optimization approach for test scheduling of system on chip

It is necessary to perform the test of system on chip,the test scheduling determines the test start and finishing time of every core in the system on chip such that the overall test time is minimized.A new test scheduling approach based on chaotic ant colony algorithm is presented in this paper.The optimization model of test scheduling was studied,the model uses the information such as the scale of test sets of both cores and user defined logic.An approach based on chaotic ant colony algorithm was proposed to solve the optimization model of test scheduling.The test of signal integrity faults such as crosstalk were also investigated when performing the test scheduling.Experimental results on many circuits show that the proposed approach can be used to solve test scheduling problems.

GR-1089-CORE对雷击浪涌测试及波形发生器的要求

NEBS认证中关于电磁兼容性和电气安全要求主要依据的标准是GR-1089-CORE。介绍了GR-1089-CORE对雷击浪涌测试的要求,并根据GR-1089-CORE对雷击浪涌发生器输出特性的要求探讨了雷击浪涌发生器的设计。

现行岩心录井标准中存在的问题及修订建议

目前国内制定的钻井取心、井壁取心、地质录井等标准均涉及岩心录井的部分内容,对现场岩心录井作业都有一定的指导作用。但随着非常规油气勘探开发的推进,现行标准中存在的一些试验参数不明确、含油气级别划分不精细、岩心整理方法相对落后、岩心管理信息量较少等问题也日渐显露。针对现行标准中存在的问题进行修订,为此提出的修订建议是:通过恒温定时确定岩心密闭试验最佳参数为60℃恒温加热120 min,根据不同储层性质精细划分含油气级别、制定泥页岩储层岩心含油气级别,变更岩心标号原则、打印代替手写标识,岩心卡片以“二维码”形式呈现。这些修订建议有利于提高岩心录井观察试验的科学性、减小录井成本、增加时效,促进岩心录井的信息化发展。

Cold Cracking of Flux Cored Arc Welded Armour Grade High Strength Steel Weldments

In this investigation, an attempt has been made to study the influence of welding consumables on the factors that influence cold cracking of armour grade quenched and tempered （Q＆.T） steel welds. Flux cored arc welding （FCAW） process were used making welds using austenitic stainless steel （ASS） and low hydrogen ferritic steel （LHF） consumables. The diffusible hydrogen levels in the weld metal of the ASS and LHF consumables were determined by mercury method. Residual stresses were evaluated using X-ray stress analyzer and implant test was carried out to study the cold cracking of the welds. Results indicate that ASS welds offer a greater resistance to cold cracking of armour grade Q＆T steel welds.

基于高中生物学核心素养培养的原创试题命制

以提升高中学生生命观念、科学思维、科学探究和社会责任四大生物学核心素养及精准备考为出发点,利用具有表观遗传特性的水稻突变体相关科研文献创设试题情境,进行原创试题的命制及分析,使学生对表观遗传产生直观认识,深入理解表型与基因型、DNA甲基化修饰与基因表达的关系,提高学生综合运用所学知识和技能解决问题的能力。

通气孔对新型不锈钢芯管平压性能影响分析

不锈钢芯管作为不锈钢桥面芯板的重要传力构件,其平压力学性能与桥面板承载能力息息相关。因钎焊工艺要求,不锈钢芯管壁上开设有双通气圆孔。为研究双通气圆孔对不锈钢芯管平压性能的影响,开展2组不同厚度不锈钢芯管平压性能试验与有限元非线性屈曲分析。通过试验结果验证采用Riks弧长法进行不锈钢芯管非线性屈曲分析方法的正确性。并考虑圆孔直径d、偏心距e、芯管壁厚t等因素,建立不同规格不锈钢芯管模型,开展非线性屈曲分析,探究多参数协同作用下对不锈钢芯管平压性能的影响分析。研究结果表明:不锈钢芯管平压试验曲线表现出明显的非线性特征,分为弹性阶段、弹塑性阶段与塑性破坏阶段;通气孔、管端扳边处转角及管脚10 mm处易优先出现局部屈曲破坏;不锈钢芯管极限荷载Pu及其对应的压缩位移δ_(u)随孔径d、偏心距e的增加而减小,随壁厚t增加而增大;芯管极限荷载Pu受孔径d的影响大于受偏心距e的影响,增大孔径使芯管极限荷载Pu下降6.00%~15.51%,而增大偏心距使芯管极限荷载Pu下降0.64%~9.22%,芯管应规避在管身中部(e/H=0.5)开孔;当孔径比d/D≯0.04、偏心比e/H≯0.3时,通气孔对芯管极限承载力影响较小,对极限荷载下的压缩位移δ_(u)不产生影响,建议将其作为通气孔设计取值。研究中获得的临界值及变化规律可用于新型不锈钢桥面芯板结构设计与优化研究。

基于TDA4VM的疲劳状态实时检测系统设计

针对传统嵌入式平台疲劳状态检测系统识别精度低和实时性差的问题,设计了一种基于TDA4VM异构多核处理器的疲劳状态实时检测系统。TDA4VM嵌入式处理器通过摄像头获取图像并进行目标检测,STM32微控制器控制外设模块,包括GPS模块、GSM模块和语音模块。在目标检测算法方面,先在YOLOX目标检测算法中引入注意力机制模块CBAM(Convolutional Block Attention Module),再对激活函数进行改进,并优化小滑窗替换算法。将训练后的YOLOX模型部署在硬件平台上,实际车载实验结果表明,在不同环境下疲劳状态检测精度可达到95.3%,同时还实现了30帧/s的实时检测。该检测系统具备精度高、实时性强和教学简易等特点,在实验教学和工程应用方面具有一定的参考价值。

建筑直流电缆的研发与应用

随着实现“双碳”目标关键技术“光储直柔技术”的发展,建筑直流配电系统亟需与之配套的直流配电电缆。通过对建筑直流电缆在研发和应用等方面的梳理,分析直流配电系统电缆应用现状和存在问题,提出建筑直流配电系统应采用专用的直流电缆。

全球通货膨胀分化:分析及中国对策

2017年以来,全球通货膨胀出现分化现象,这是自20世纪70年代布雷顿森林体系崩溃后少见的现象。逆全球化是当前全球通胀分化的主要原因之一。本文选取具有代表性的发达经济体的通胀情况进行分析,以此参照对比其与美国及其与中国通胀变化分化的情况。研究时间范围为2017年2月—2023年10月,涵盖两个阶段,涉及八个国家。采用协整检验和主成分分析发现,中国和美国是全球通胀分化的重要两极,主要发达经济体追随美国。中国未来面临逆全球化挑战的严峻程度和不确定性呈现上升趋势。我国应以“进”促“稳”,稳中求进,先立后破;研究把握主要发达国家在现有国际经济秩序中发挥主导作用的系统性的活动规律,探索中国在现有国际经济秩序中发挥更大作用、确保自身经济高水平安全发展的有效路径和方法。

地浸砂岩型铀矿松散岩层单动双管取心钻具的研制与试验

为解决单管钻具取心工艺方法在深部目的层/矿层等松散岩层取心中存在的取心质量差、取心效率低和操作难度大的问题,开展了地浸砂岩型铀矿松散岩层单动双管钻具的研制和试验。通过设计和改进单动机构、断心结构、液力退心机构和快拆机构,研制了两类分别具有可直接液力退心和快速拆卸功能的SD型单动双管钻具。试验结果表明:SD110型双管钻具可在免拆内管的情况下实现地表快速液力退心,提高双管钻具退心效率;SDKC110型钻具可快速拆装更换内管,实现退心和钻进平行作业。与单管钻具相比,SD系列单动双管钻具在松散岩层的平均回次长度提高28.62%,平均机械钻速提高11.61%;与常规单动双管钻具相比,退心操作时间降低了32.69%。SD系列单动双管钻具适用于在松散破碎地层进行取心钻进应用,可有效提高岩心采取效率和岩心质量。

DFT Techniques in DSP Chip Core NDSP25

Design for Testability(DFT) is critical in chip design.DFT techniques insert hardware logic to an original design,in order to improve testability of the chip,and thus reduce test cost significantly.In this paper,we introduces the most frequently used DFT techniques,then put emphasis on the DFT policy and the DFT realization of the NDSP25 chip core,and analyses the result at last.

基于核心素养的高考数学情境化试题的比较分析

从试题呈现方式、情境来源、涉及素养、情境类型和评价等级5个维度出发,对2020—2022年新高考Ⅰ卷及2023年新课标Ⅰ卷和2020—2023年高考数学天津卷试题进行比较分析发现,命题者能够重视情境化试题的价值,科学合理地设计情境化试题,力求试题情境以更多元化的方式呈现,从而考查学生的关键能力.

变速抽水蓄能电机在发电工况不同转速下磁场和损耗研究

本文对变速抽水蓄能发电电动机的电压方程、磁链方程、电磁转矩方程和运动方程进行了推导,并建立了10MW变速抽水蓄能发电电动机二维电磁场的数学方程和物理模型,对变速抽水蓄能发电电动机的电磁场数学方程进行了计算,得到了变速抽水蓄能电机在发电机工况下超同步速时定子电压和定子电流的波形,分析了变速抽水蓄能电机在发电机工况下不同转速时磁密的分布规律,研究了不同转速下定子铁芯损耗和转子铁芯损耗占总铁芯损耗比例的变化规律。搭建了10MW变速抽水蓄能发电电动机样机试验测试平台,通过试验测试得到的结果与计算结果较为接近。