Developmental change in the acuity of the "number sense": The approximate number system in 3-, 4-, 5-, and 6-year-olds and adults.

Behavioral, neuropsychological, and brain imaging research points to a dedicated system for processing number that is shared across development and across species. This foundational Approximate Number System (ANS) operates over multiple modalities, forming representations of the number of objects, sounds, or events in a scene. This system is imprecise and hence differs from exact counting. Evidence suggests that the resolution of the ANS, as specified by a Weber fraction, increases with age such that adults can discriminate numerosities that infants cannot. However, the Weber fraction has yet to be determined for participants of any age between 9 months and adulthood, leaving its developmental trajectory unclear. Here we identify the Weber fraction of the ANS in 3-, 4-, 5-, and 6-year-old children and in adults. We show that the resolution of this system continues to increase throughout childhood, with adultlike levels of acuity attained surprisingly late in development. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

美国《保健物理》(Health Physics)杂志英文摘要(2022年122卷第1期)

Dose Estimation for Exposure to Radioactive Fallout from Nuclear Detonations Steven L.Simon1,AndréBouville2,Harold L.Beck3,Lynn R.Anspaugh4,Kathleen M.Thiessen5,F.Owen Hoffman5,Sergey Shinkarev6(1.National Cancer Institute,National Institutes of Health,Bethesda,MD;2.National Cancer Institute,National Institutes of Health,Bethesda,MD(retired);3.US Department of Energy(retired),New York,NY;4.Department of Radiology,University of Utah(Emeritus),Henderson,NV;5.Oak Ridge Center for Risk Analysis,Inc.,Oak Ridge,TN.     

Neural Representation of Open Surfaces

Neural implicit surfaces have emerged as an effective, learnable representation for shapes of arbitrary topology. However, representing open surfaces remains a challenge. Different methods, such as unsigned distance fields (UDF), have been proposed to tackle this issue, but a general solution remains elusive. The generalized winding number (GWN), which is often used to distinguish interior points from exterior points of 3D shapes, is arguably the most promising approach. The GWN changes smoothly in regions where there is a hole in the surface, but it is discontinuous at points on the surface. Effectively, this means that it can be used in lieu of an implicit surface representation while providing information about holes, but, unfortunately, it does not provide information about the distance to the surface necessary for e.g. ray tracing, and special care must be taken when implementing surface reconstruction. Therefore, we introduce the semi-signed distance field (SSDF) representation which comprises both the GWN and the surface distance. We compare the GWN and SSDF representations for the applications of surface reconstruction, interpolation, reconstruction from partial data, and latent vector analysis using two very different data sets. We find that both the GWN and SSDF are well suited for neural representation of open surfaces.     

变长线齿轮测量尺寸的计算

本文基于变长线齿轮传动齿轮副的特点，提出了齿轮公法线跨齿数、长度以及弦齿厚的计算公式，并针对武钢○七工程某轧机上变长线齿轮传动，给出了计算实例。     

曲柄摇杆机构的摇杆摆角和运动连续的条件

本文对曲柄摇杆机构的摇杆摆角进行了研究。论证了小的几何取值范围和工程取值范围；揭示了缩减的现象，分析了缩减的原因、结果和条件，导出了缩减量的计算表达式；在此基础上，论证了曲柄摇杆机构运动连续的条件。     

A method for reduction of number of actuators in Independent Modal Space Control

In this paper, a modified Independent Modal Space Control (IMSC) that relaxes the fundamental hardware requirement of IMSC is proposed for handling the vibration and attitude control problem of large, flexible structures. The method incorporates a new switching algorithm for dynamically selecting controlled modes and a novel design technique for determining the modal control force. The main advantage of the proposed method is that it minimizes the discontinuity of the modal control forces and assures the asymptotic stability of the closed-loop system. The simplicity and efficiency of the method is demonstrated through an example involving vibration control of a cantilevered beam. The system performance and stability of the proposed method is compared with previously published methods that also seek to reduce the number of actuators in IMSC.     

630吨摩擦螺旋压力机的冲顶分析与研究

本文以产品质量和工艺过程为基本要求,通过对工作机构的能量及螺杆螺纹头数的分析,找出解决 ６３０ 吨摩擦螺旋压力机冲顶问题的方法—螺杆螺纹头数由四头改为两头。     

Some remarks on the security of the identification scheme based on permuted kernels

We present in this paper an idea of how to reduce the number of possible permutations when trying to solve the permuted kernels problem. We refer to the identification scheme of Shamir [2] and we also show how a dishonest prover can maximize his prospects to pass the test.     

Incompleteness,Complexity, Randomness and Beyond

Gödel's Incompleteness Theorems have the same scientific status as Einstein's principle of relativity, Heisenberg's uncertainty principle, and Watson and Crick's double helix model of DNA. Our aim is to discuss some new faces of the incompleteness phenomenon unveiled by an information-theoretic approach to randomness and recent developments in quantum computing.     

柴油-甲醇乳化燃料乳化剂的最佳HLB值及水含量的影响

柴油机中掺烧醇的最大难点之一在于难以获得价廉、稳定的柴油-甲醇乳化燃料。作者研究了柴油-甲醇乳化燃料乳化剂的最佳HLB值以及不同含水量对最佳HLB值的影响。研究结果表明：柴油-甲醇乳化燃料乳化剂的最佳HLB值在3．5左右，当柴油甲醇乳化燃料中含水形成了甲醇-水-柴油三元乳化燃料时，其最佳HLB值与柴油-水的最佳HLB值相同，且三元乳化燃料乳化剂的最佳HLB值不随含水量的增加而变化，但随着含水量增加，乳化燃料分层时间会产生变化；在柴油-甲醇-水乳化液中，当水在甲醇-水混合液中的比例为40％左右时，甲醇-水-柴油三元乳化燃料(柴油：甲醇 水=8：1)的分层时问最长，即在柴油-甲醇乳化燃料中加水有利于提高乳化燃料的稳定性。