烧结钕铁硼微观组织对磁性能的影响

研究了不同烧结和时效工艺的N35(16.70Nd，16．50Pr，0．30Dy,1．15B，0．30Al)和N30(10．60Nd，23．40Pr，0．30Dy，1．20B，0．30Al)两种牌号钕铁硼磁体的晶粒大小和形态对磁性能的影响。结果得出：剩磁Br随晶粒尺寸的增大有极大值，内禀矫顽力Hcj及最大磁能积BHm随晶粒尺寸的增大而降低。高磁能积磁体的最佳组织为晶粒均匀、细小、呈球形，没有聚集成块的富钕相和富硼相存在。     

Combined Model-Based Prediction for Non-Invasive Prenatal Screening

The risk of chromosomal abnormalities in the child increases with increasing maternal age. Although non-invasive prenatal testing (NIPT) is a safe and effective prenatal screening method, the accuracy of the test results needs to be improved owing to various testing conditions. We attempted to achieve a more accurate and robust prediction of chromosomal abnormalities by combining multiple methods. Here, three different methods, namely standard Z-score, normalized chromosome value, and within-sample reference bin, were used for 1698 reference and 109 test samples of whole-genome sequencing. The logistic regression model combining the three methods achieved a higher accuracy than any single method. In conclusion, the proposed method offers a promising approach for increasing the reliability of NIPT.     

Mutation of GmIPK1 Gene Using CRISPR/Cas9 Reduced Phytic Acid Content in Soybean Seeds

Phytic acid (PA) acts as an antinutrient substance in cereal grains, disturbing the bioavailability of micronutrients, such as iron and zinc, in humans, causing malnutrition. GmIPK1 encodes the inositol 1,3,4,5,6-pentakisphosphate 2-kinase enzyme, which converts myo-inopsitol-1,3,4,5,6-pentakisphosphate (IP₅) to myo-inositol-1,2,3,4,5,6-hexakisphosphate (IP₆) in soybean (Glycine max L.). In this study, for developing soybean with low PA levels, we attempted to edit the GmIPK1 gene using the CRISPR/Cas9 system to introduce mutations into the GmIPK1 gene with guide RNAs in soybean (cv. Kwangankong). The GmIPK1 gene was disrupted using the CRISPR/Cas9 system, with sgRNA-1 and sgRNA-4 targeting the second and third exon, respectively. Several soybean Gmipk1 gene-edited lines were obtained in the T₀ generation at editing frequencies of 0.1–84.3%. Sequencing analysis revealed various indel patterns with the deletion of 1–9 nucleotides and insertions of 1 nucleotide in several soybean lines (T₀). Finally, we confirmed two sgRNA-4 Gmipk1 gene-edited homozygote soybean T₁ plants (line #21-2: 5 bp deletion; line #21-3: 1 bp insertion) by PPT leaf coating assay and PCR analysis. Analysis of soybean Gmipk1 gene-edited lines indicated a reduction in PA content in soybean T₂ seeds but did not show any defects in plant growth and seed development.     

Performance variation of bendable polymer electrolyte fuel cell based on Ag nanowire current collector under mixed bending and twisting load

The bendable fuel cell based on polydimethylsiloxane and Ag nanowire current collectors was fabricated and characterized as it is subject to mixed bending and twisting load. The power density of the fuel cell decreased with the increasing twisting angle regardless of the application of bending. However, the fuel cell with the bending component showed higher power densities than that without bending in all twisting angles. By calculating the stress distribution inside the fuel cell using finite-element method, it was found that the higher performance in the bendable fuel cell under both bending and twisting load is due to the stronger compressive stress on a membrane-electrode assembly induced by the bending load. From electrochemical impedance investigation, it was visualized that although the twisting load increases both electrolyte and electrode resistances, this effect seems to be canceled by the bending, leading to the increased performance.     

Automated structural analysis of SCR‐style software requirements specifications using PVS

The importance of effective requirements analysis techniques cannot be overemphasized when developing software requiring high levels of assurance. Requirements analysis can be largely classified as either structural or functional. The former investigates whether definitions and uses of variables and functions are consistent, while the latter addresses whether requirements accurately reflect users' needs. Verification of structural properties for large and complex software requirements is often repetitive, especially if requirements are subject to frequent changes. While inspection has been successfully applied to many industrial applications, the authors found inspection to be ineffective when reviewing requirements to find errors violating structural properties. Moreover, current tools used in requirements engineering provide only limited support in automatically enforcing structural correctness of the requirements. Such experience has motivated research to automate straightforward but tedious activities. This paper demonstrates that a theorem prover, PVS (Prototype Verification System), is useful in automatically verifying structural correctness of software requirements specifications written in SCR (Software Cost Reduction)‐style. Requirements are automatically translated into a semantically equivalent PVS specification. Users need not be experts in formal methods or power users of PVS. Structural properties to be proved are expressed in PVS theorems, and the PVS proof commands are used to carry out the proof automatically. Since these properties are application independent, the same verification procedure can be applied to requirements of various software systems. Copyright © 2001 John Wiley & Sons, Ltd.     

Numerical methods for analyzing the effects of uncertainties on the dynamics of periodic structures

Various approaches are proposed and compared for analysing the effects of structural irregularities and parameter uncertainties on the dynamics of finitely long, one-dimensional, mono-coupled, nearly periodic assemblies with and without structural damping. Computational concerns are raised in regard to the classical method of modal analysis, and alternative methods are formulated which allow for the numerically efficient determination of the exponential decay constant. While modal analysis and Cramer's rule require the solution of an eigenvalue problem, the matrix inversion and matrix partitioning approaches avoid costly eigenvalue computations and require only cost-effective algebraic manipulations. Therefore, implementation of either the direct inversion technique or matrix partitioning both simplifies the analysis and cuts computational costs substantially. © 1997 John Wiley & Sons, Ltd.     

FACTORS INFLUENCING SOLID SOLUBILITIES OF RARE-EARTHS IN Pd

1.IntroductionInmostmetalsolvents,therare-earths(RE)areinsolubleorhavequitesmallsolidsolubilities.EveninsolventslikeAgandAu,themaximumsolidsolubilitiesofheavyrare-earthsarelessthan1oat.%,whichhavealreadybeenreviewedinRefs.[1-3].ThesoIidsolubilitiesofrare-earthsinPd,however,aregenerallylargerthan1Oat.%exceptafewlightrare-earthssuchasLaandNdwhichhavequitesmallvalues.Althoughthealloyingbehaviorofpalladiumwithrare-earthswasdiscussedbasedontheatomicsizeeffectl4],thespecialityforthesolidsolubili…     

蒸汽吞吐井地层水判别方法

本文通过对某热采试验区水样资料的统计、分析,提出了用生产动态特征、水化学特征及电性特征对地层水的综合判别方法;指出用绍勒尔碱交换指数(IBE)可以定量地划分油水层,在对实际资料分析的基础上,给出了几个水化学特征值及电性特征值方面的界限。     

Unusually Fast Optically Induced Birefringence in Polyoxetanes Bearing 4‐(N,N‐Diphenyl)amino‐4′‐nitroazobenzene Chromophores

Two new polyoxetane polymers bearing azobenzene‐type chromophore pendants were prepared, and their photoinduced molecular orientation and relaxation were studied. The two polymers differ in the mode of attachment of the chromophores, which are either laterally ( Pox 1 ) or perpendicularly ( Pox 2 ) bound to the polymer backbone. The two polymers reveal unusually fast (∼2 s to saturation at 0.4 W/cm²) photoinduced reorientation of chromophores and decay behavior at room temperature. Side‐on attachment of the chromophores ( Pox 1 ) results in a significantly faster response to polarized light and higher maximum birefringence than end‐on attachment. The kinetics of photoinduced orientation and relaxation decay were quantitatively analyzed and the results are discussed in relation to the structures of the polymers.     

海面雷达最大探测距离分布规律快速计算方法研究

为解决海面雷达最大探测距离分布规律计算耗时过长的问题,论文首先分析蒸发波导条件下雷达最大探测距离计算方法的特性,给出蒸发波导高度、理查森数和风速对雷达最大探测距离的影响,随后在此基础上提出用查表法计算每条海面气象水文记录对应的雷达最大探测距离,并总结出构建标准距离表的原则。利用查表法很大程度上缩短了计算时间,计算结果与直接计算偏差较小,能满足快速建立海面雷达最大探测距离分布规律的需要。