Fuzzy Model Free Adaptive Control for Rotor Blade Full-Scale Static Testing

To eliminate the node traction coupling during wind turbine blade full-scale static testing,a model free adaptive control algorithm is presented based on fuzzy control performance function compensation. Based on the universal model theory,the fuzzy model free adaptive control( FMFAC) algorithm is designed by configuring the spot static testing experiences as compensation function F( ·). Then the algorithm implementation process is provided and its quick convergence is proved. Using software to establish static load coupling model of multi-nodes,simulate and verify the validity of FMFAC algorithm,which is applied to wind turbines blade full-scale static testing. The results show that the adaptive decoupling ability of FMFAC is better. The traction of four load points can stay steady and change coordinately. Process error is not over ± 6 k N. The error rate is lower than 1% in special phase.This algorithm effectively eliminates the traction coupling of the static testing process,and makes wind turbine blade testing steadily.

Study on Model Tests and Hydrodynamic Force Models for Free Spanning Submarine Pipelines Subjected to Earthquakes

A test rig is built to model the dynamic response of submarine pipelines with an underwater shaking table in the State Key Laboratory of Coastal and Offshore Engineering, Dalian University of Technology, China. Model tests are carried out to consider the effects of exciting wave directions and types. Based on the experimental results, two hydrodynamic force models derived from Morisen equation and Wake model are presented respectively. By use of hydrodynamic force models suitable for free spanning submarine pipelines under earthquakes, diseretized equations of motion are obtained and finite element models are established to analyze dynamic response of free spanning submarine pipeline subjected to multi-support seismic excitations. The comparison of numerical results with experimental results shows that the improved Morison and Wake hydrodynamic force models could satisfactorily predict dynamic response on the free spanning submarine pipelines subjected to earthquakes.

Research of testing method based on UML statecharts

Unified modeling language （UML） is a powerful graphical modeling language with intuitional meaning. It provides various diagrams to depict system characteristics and complex environment from different viewpoints and different application layers. UML-based software development and modeling environments have been widely accepted in industry, including areas in which safety is an important issue such as spaceflight, defense, automobile, etc. To ensure and improve software quality becomes a main concern in the field. As one of the key techniques for software quality, software testing can effectively detect system faults. UML based software testing based is an important research direction in software engineering. The key to software testing is the generation of test cases. This dissertation studies an approach to generating test cases from UML statecharts.

Development and Application of an in Situ Penetrator for Rapid Strength Testing of Submarine Sediment

In marine engineering, the strength of a submarine sediment is an indispensable parameter for assessment of construction. In this study, a free-fall cone penetrator named IPen was developed to realize a rapid and efficient measurement of sediment strength. The equipment is characterized by modular design and self-contained data acquisition. It is equipped with an acceleration sensor, a water pressure sensor, and a piezocone penetration test(CPTu) probe. It is designed to be released from near seabed surface with a releaser and then fall freely to provide a higher penetration velocity. Its maximum working depth is approximately 2500 m and maximum penetration depth is approximately 3 m. To derive the correlation between penetration resistance and sediment strength, a calibrator was devised to determine the penetration-rate factor. In addition, the factor applicable to in situ test points was determined in laboratory experiments. In June 2016, the IPen was tested in situ in the South Yellow Sea, China, during a shared voyage funded by the National Science Foundation. Meanwhile, undisturbed column samples were collected for laboratory tests. Based on the in situ test results, it was demonstrated that the IPen could accurately record the working states of various sensors during the freely falling course. IPen test results reliably reflected the sediment strength at all the testing points when compared with laboratory calibration tests, in situ vane tests and penetration tests, laboratory penetration tests, and unconsolidated and undrained triaxial compression tests.

Effects of Tuned Mass Damper on Wind-Induced Vibration of Free Standing Pylon by Wind Tunnel Test

In order to assess the effects of tuned mass dampers （TMDs） on wind actions, an aeroelastic model with a scale of 1：60 was constructed. Tests were performed in an atmospheric boundary layer wind tunnel to investigate the buffeting response of the pylon with a TMD fixed by a wire rope instead of a spring. The model was tested under different levels of damping. The experimental and numerical results showed that with the TMD in the optimal condition, the buffeting response was reduced by 47%.

Dynamic Testing of Elastic Modulus,Shear Modulus,and Poisson’s Ratio of Bamboo Scrimber

The bamboo scrimber is an anisotropic material.The elastic constant values of the bamboo scrimber specimens measured by the dynamic and static methods are consistent,and the dynamic test method has the advantages of rapidity,simplicity,good repeatability,and high precision.Bamboo scrimber has strong potential as a building material,and its elastic constant is an important index to measure its mechanical properties.To quickly,simply,non-destructively,and accurately detect the elastic constant of the bamboo scrimber,they were dynamically tested by the free plate transient excitation method and cantilever plate torsional vibration method.The static four-point bending method was used to verify the accuracy and reliability of the dynamic elastic modulus,shear modulus,and Poisson’s ratio of the bamboo scrimber.The mechanism analysis and evaluation of the quality grade,homogeneity,and size effect of the bamboo scrimber whole board were carried out.The main results show that the dynamic elastic modulus,shear modulus,and Poisson’s ratio of the bamboo scrimber are 12 GPa,1500 MPa,and 0.31,respectively,which meet the requirements of GB/T 40247-2021 for structural bamboo scrimber.

Noninvasive Prenatal Testing for Fetal Chromosomal Abnormalities Using Massively Parallel Sequencing: Clinical Experience from 7910 Korean Pregnancies

Objective: The purpose of this study is to review the clinical experience and performance of noninvasive prenatal testing (NIPT) method, using cell-free DNAto detect chromosomes 21, 18, 13, X, and Y abnormalities in over 7910 clinical samples from South Korean population. Method: Pregnant women between 1st of November 2015 to 18th of February 2018, with obstetric clinical findings participated in the study. NIPT was performed based on masivelly parallel sequencing with 0.3× low coverage paired-end sequencing using cell-free DNA in maternal plasma. Further invasive prenatal testing was recommended for pregnant women with positive NIPT results. Results: Of the total 7910 participants, 7890 (99.75%) were tested for NIPT and the remaining 20 (0.25%) were below the Quality Control (QC) standards. T13, T18, XXX, XXY and XYY had 100% of sensitivity, specificity, positive predictive values (PPV) and accuracy. The overall sensitivity was 100% and specificity, PPV and accuracy of all chromosomal abnormalities with further validation were 99.92%, 94.25%, and, 99.92% respectively. Conclusion: Our NIPT results showed high positive predictive value for the detection of autosomal trisomies and sex chromosome aneuploidies in our sample cohort.

Multiple z-Score Based Method for Noninvasive Prenatal Test Using Cell-Free DNA in Maternal Plasma

Objective: To improve the detecting accuracy of chromosomal aneuploidy of fetus by non-invasive prenatal testing (NIPT) using next generation sequencing data of pregnant women’s cell-free DNA. Methods: We proposed the multi-Z method which uses 21 z-scores for each autosomal chromosome to detect aneuploidy of the chromosome, while the conventional NIPT method uses only one z-score. To do this, mapped read numbers of a certain chromosome were normalized by those of the other 21 chromosomes. Average and standard deviation (SD), which are used for calculating z-score of each sample, were obtained with normalized values between all autosomal chromosomes of control samples. In this way, multiple z-scores can be calculated for 21 autosomal chromosomes except oneself. Results: Multi-Z method showed 100% sensitivity and specificity for 187 samples sequenced to 3 M reads while the conventional NIPT method showed 95.1% specificity. Similarly, for 216 samples sequenced to 1 M reads, Multi-Z method showed 100% sensitivity and 95.6% specificity and the conventional NIPT method showed a result of 75.1% specificity. Conclusion: Multi-Z method showed higher accuracy and robust results than the conventional method even at low coverage reads.

Proposal for a Loophole-Free Bell Test with Electron Spins of Donors in Silicon

So far, all experimental tests of Bell inequalities which must be satisfied by all local realistic hidden-variable theories and are violated by quantum mechanical predictions have left at least one loophole open. We propose a feasible setup allowing for a loophole-free test of the Bell inequalities. Two electron spin qubits of donors31P in a nanoscale silicon host in different cavities 300 m apart are entangled through a bright coherent light and postselections using homodyne measurements. The electron spins are then read out randomly and independently by Alice and Bob, respectively, with unity efficiency in less than 0.7 μs by using optically induced spin to charge transduction detected by radio-frequency single electron transistor. A violation of Bell inequality larger than 37% and 18% is achievable provided that the detection accuracy is 0.99 and 0.95, respectively.

Permutation Test在假设检验中的应用

本文介绍了一种实用的、基于大量计算的统计推断方法———Permutation test。该法根据所研究的问题构造检验统计量,并利用手头样本,按排列组合的原理导出检验统计量的理论抽样分布;若难以导出确切的理论分布,则采用抽样模拟的方法估计其近似分布,然后求出从该分布中获得手头样本及更极端样本的概率(P值),并界定此概率值,作出推论。本方法属分布自由检验,适用于总体分布未知的小样本资料,以及某些难以用常规方法分析的资料之假设检验问题。本文就“Permutation”的含义,“Permutation tes”t的特点,“统计量的构造”,“模拟次数的选择”,应用进展等问题展开探讨。

FREE模型在面向对象测试中的应用研究

在面向对象分析设计中 ,对象的行为通常与其状态紧密相关。因此 ,基于状态的测试成为面向对象软件中一个有效的测试方法。对FREE模型进行了研究 ,分析了该模型的优缺点及适用范围 ,并将其应用于面向对象软件测试中 ,为基于状态的测试提供一个类行为的可测模型 ,有利于提高面向对象的测试质量。

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.

Failure Modes of Lead Free Solder Bumps Formed by Induction Spontaneous Heating Reflow

The shear failure modes and respective failure mechanism of Sn3.5Ag and Sn3.0Ag0.5Cu lead-free solder bumping on Au/Ni/Cu metallization formed by induction spontaneous heating reflow process have been investigated through the shear test after aging at 120℃ for 0, 1, 4, 9 and 16 d. Different typical shear failure behaviors have been found in the loading curves （shear force vs displacement）. From the results of interracial morphology analysis of the fracture surfaces and cross-sections, two main typical failure modes have been identified. The probabilities of the failure modes occurrence are inconsistent when the joints were aged for different times. The evolution of the brittle NiaSn4 and Cu-Ni-Au-Sn layers and the grains coarsening of the solder bulk are the basic reasons for the change of shear failure modes.

A Calculation Method of Rolling Characteristics of Canard Missile with Free-Spinning Tails

The steady flow field of a canard missile on different angles of attack and Mach numbers were studied. Based on analysis, a method was proposed to reduce the calculation for the rolling characteristics of the canard missile with free-spinning tails, and was tested to obtain the relations between rolling moment coefficient, Mach number, and angle of attack. All the computed rolling moment coefficients obtained from the proposed method greatly agreed with the experimental results of FD-06 wind tunnel in CAAA, which proved that the method can not only reduce the calculation cost but also keep precision in calculating the rolling characteristics of canard missiles.

The Danger within:Covid-19 Affinity for ACE2 Receptors in Adipose Tissue and Testes.The Protective Effects of Estradiol,Fitness,and Weight Management

The imminent danger of the Covid-19 pandemic has accelerated research in pharmaceuticals that either target the viral Spike proteins fusion with ACE2 receptors,or the infectious RNA replication that often overwhelms immune defences.The scope of this review was to elucidate the main human vulnerabilities to Covid-19,including the accumulation of ACE2 receptors in testes,adipose tissue,thyroid,heart and kidneys that escalate viral affinity in males,the aged,and certain medical conditions,including diabetes,CVD,and pulmonary diseases.Pre-existing inflammation inherent in obesity may exacerbate the“cytokine storm,”a rampaging immune reaction during the course of Covid-19 that is deleterious to the host.We examined the molecular dynamics illustrating the action of new therapeutics necessary for Covid-19 patients;the estradiol advantage hypothesis;alternative therapies including hormone replacement procedures and mesenchymal stem cells;plus preventive and protective interventions.The current perspective also explored the primary components of dysregulated health predisposing individuals to Covid-19,including hormonal imbalance,increased lipids and lipoproteins,thyroid dysfunction,degraded fitness,and age-related testosterone decline accompanied by cortisol increase that provokes stress eating behaviours and weight accumulation.Obesity increases the probability of Covid-19 infection due to its abundance of ACE2 receptors;while physical activity may decrease Covid-19 vulnerability,by reducing fat and increasing muscle mass that manifests a relatively inhibited ACE2 expression.Several weight management solutions feature lasers and radiofrequency which diminish subcutaneous adiposity but do not enhance fitness.A data metanalysis of seven recently published clinical studies on 95 obese individuals,73 males and 22 females with an average BMI of 30.9,demonstrated visceral fat reduction combined with increased skeletal muscle mass.It also revealed a statistically significant decrease in BMI,lipids,lipoproteins,inflammation and toxicity as measured by CRP,Creatinine and Bilirubin respectively,juxtaposed by optimally healthier levels of Cortisol,Testosterone,Free T3,IGF-1,Insulin,and the appetite controlling hormones Leptin and Ghrelin.

隔震装置阻尼机构的参数设计与振动台试验

为了改善浮放物体隔震装置中阻尼力的施加方式,研制出一款阻尼机构。对其构造和工作机理进行阐述,推导出了它的力学特征表达式,并验证了分析模型的准确性。结合某文物隔震装置的目标性能,利用数值方法对阻尼机构的参数进行设计,并对比振动台试验。结果表明:该阻尼机构结构简单,性能稳定;经阻尼参数优化后的隔震装置在满足位移限值的情况下达到了设定的隔震目标;试验与数值分析结果相吻合,证明了阻尼机构参数设计的正确性,同时也检验了隔震装置的安装和运行质量。其中,试验与数值分析结果的吻合程度,尤其是位移时程曲线的吻合程度,可为浮放物体隔震装置的方案对比和质量评估提供思路。

圆球上浮运动特性数值仿真及试验研究

以圆球状浮体为对象,研究尺度、密度比(圆球密度与流体密度比值)对其上浮运动性能的影响。建立静水中圆球上浮运动数值模拟方法,通过与模型试验测试结果对比,验证数值方法的可靠性。通过验证的计算方法对不同尺度和密度比的圆球上浮运动过程进行分析,结果表明:圆球在稳定上浮阶段的阻力系数大致为常数1,不随圆球尺度和密度比变化产生较大变化;若2个圆球满足相似条件且尺度之比为λ,则它们的稳定速度之比和上浮总时间之比大致为λ0.5。本研究通过对圆球上浮运动的计算和分析,寻求不同尺度圆球上浮运动之间的相关性,可为其他结构物上浮运动性能的尺度相关性研究分析提供参考依据。

海底电缆动态疲劳试验方法研究

海底电缆安装敷设与在位运行期间承受长期、复杂的动态荷载,容易发生疲劳失效。针对悬跨海底电缆动态行为复杂,缺乏模拟海底电缆与海床脱离点处疲劳试验方法的问题,该文搭建悬跨海底电缆与海床接触的原型疲劳试验装置,开发悬跨海底电缆疲劳试验方法,开展内部疲劳失效发生层动态应变信息测量方法研究。结果表明:动态疲劳试验能够准确模拟海底电缆疲劳受力状态并还原其在振动荷载下的结构响应,试验过程中的加载拉力误差低于15%,加载曲率误差低于10%,对海底电缆内部铅护套层的应变测量误差低于10%。该文提出的动态疲劳试验方法对海底电缆的结构失效验证具有很好的参考价值。

曲线轨道式隔震装置的结构优化与应用研究

针对浮放物体的防震保护需求,研发出一款基于新型抗侧移组件的曲线轨道式隔震装置。阐述它的构造特点和运行机制,并依据结构原理制作模型,通过试验与理论对比来检验模型的运行质量进而验证方案的可行性。然后结合雨花阁内文物来设计样机,采用多条楼面波进行样机的振动台试验,测试其隔震效果。最后探讨建筑滤波效应对该类隔震装置设计的影响。研究结果表明:曲线轨道式隔震装置经优化后不仅零部件功能清晰,结构简单易加工,而且具备整体性强、运行质量高以及后期可扩展等优势。试验模型的零部件能充分发挥各自功能,尤其是抗侧移组件极大提高了模型的稳定性和可靠性,理论分析与试验结果吻合良好。结合案例所设计的样机虽具有较好的隔震性能,但限于非线性双自由度的结构特点,重复试验的响应结果存在差异,工程应用中应予以重视。当楼面波不易获取且隔震装置周期远离建筑自振周期时,依据楼面加速度放大系数,将调幅后的原始波作为隔震装置设计依据是可行的且结果偏保守。

Vangenes Cell-Free DNA采血管与 Streck Cell-Free DNA采血管在无创产前检测应用中的效果比较

目的:比较Vangenes■Cell-Free DNA采血管和Streck■Cell-Free DNA 采血管对血液样品的运输保存效果.方法:通过静脉抽血, 18名志愿者分别使用Vangenes■Cell-Free DNA 采血管与Streck■Cell-Free DNA采血管各采集一管10mL血液.经过约50h运输样本回到实验室,进行血浆分离、游离DNA提取、构建文库、上机测序并进行建库浓度、测序数据的unique read counts、 GC%以及duplication值等分析.结果:经比较, Vangenes ?Cell-Free DNA采血管保存样品在血浆颜色、建库浓度以及测序数据的unique read counts、 GC%以及duplication值等达到了Streck■Cell-Free DNA 采血管保存样品相似的结果,二者不存在显著性差异.结论:在血液样品运输保存过程中, Vangenes■Cell-Free DNA采血管可有效阻止有核细胞破裂导致的基因组DNA对于游离DNA的污染,对于利用胎儿游离DNA进行的无创产前检测技术具有重要意义.