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Unprecedented j.ST Observations Contest Cosmological Canons

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Engineering 2024年第6期37卷 6-9页

作者： chris Palmer Senior Technology Writer

After more than 18 months of nearly flawless operation,the j.mes Webb Space Telescope(j.ST)continues to deliver amazement,making unexpected discoveries,adding new wrinkles to known phenomena,and calling into question long-held theories of how the universe works.“The instruments are working amazingly well,in essentially all cases better than expected,”said Garth Illingworth,professor emeritus of astronomy and astrophysics at the University of California,Santa Cruz(CA,USA),and one of the three originators of the mission over three decades ago.“It has exceeded every one of its performance requirements,which is truly amazing when you think about how complex it is.”That complexity has included three decades of planning,design,and construction,followed by launch and maneuvering 1.5106 km from Earth to its second Lagrange(L2)orbit,unfolding and locking into position the 18 segments of its 6.5 m diameter main mirror,and deploying 8 motors,90 cables,and some 400 pulleys to unfurl its fragile sunshield[1,2].

关键词： universe Observation Cosmo

Attitude control of multi-spacecraft systems on SO(3)with stochastic links failure

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Chinese j.urnal of Aeronautics 2024年第3期37卷 320-331页

作者： KANG Zeyu SHEN Qiang WU Shufan chris j.DAMAREN MU Zhongcheng School of Aeronautics and Astronautics Shanghai Jiao Tong UniversityShanghai 200240China Institute for Aerospace Studies University of TorontoTorontoOntario M3H 5T6Canada

In this paper,for Multi-Spacecraft System(MSS)with a directed communication topology link and a static virtual leader,a controller is proposed to realize attitude consensus and attitude stabilization with stochastic links failure and actuator ***,an MSS attitude error model suitable for a directed topology link and with a static virtual leader based on SO(3)is derived,which considers that the attitude error on SO(3)cannot be defined based on algebraic ***,we design a controller to realize the MSS on SO(3)with attitude consensus and attitude stabilization under stochastic links failure and actuator ***,the simulation results of a multi-spacecraft system with stochastic links failure and a static virtual leader spacecraft are demonstrated to illustrate the efficiency of the attitude controller.

关键词： Multi-spacecraft systems Attitude consensus Attitude stabilization Stochastic links failure Super-martingale convergence

Universal insertion of molecules in ionic compounds under pressure

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National Science Review 2024年第1期11卷 120-128页

作者： Feng Peng Yanming Ma chris j.Pickard Hanyu Liu Maosheng Miao College of Physics and Electronic Information Luoyang Normal University Department of Chemistry and Biochemistry California State University Northridge State Key Laboratory of Superhard Materials & Key Laboratory of Material Simulation Methods and Software of Ministry of Education College of Physics Jilin University International Center of Future Science Jilin University Department of Materials Science & Metallurgy University of Cambridge Advanced Institute for Materials Research Tohoku University Department of Earth Science University of California Santa Barbara

Using first-principles calculations and crystal structure search methods, we found that many covalently bonded molecules such as H2, N2, CO2, NH3, H2O and CH4may react with NaC l, a prototype ionic solid,and form stable compounds under pressure while retaining their molecular structure. These molecules,despite whether they are homonuclear or heteronuclear, polar or non-polar, small or large, do not show strong chemical interactions with surrounding Na and Cl ions. In contrast, the most stable molecule among all examples, N2, is found to transform into cyclo-N5-anions while reacting with NaC l under high pressures. It provides a new route to synthesize pentazolates, which are promising green energy materials with high energy density. Our work demonstrates a unique and universal hybridization propensity of covalently bonded molecules and solid compounds under pressure. This surprising miscibility suggests possible mixing regions between the molecular and rock layers in the interiors of large planets.

关键词： molecule-solid hybrid materials high-pressure crystal structure prediction density functional theory planet interior

European Union Issues World’s First Comprehensive Regulations for Artificial Intelligence

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Engineering 2024年第7期38卷 5-7页

作者： chris Palmer Senior Technology Writer

In March 2024,European Union(EU)lawmakers passed the world’s first comprehensive set of regulations governing the use of artificial intelligence(AI)[1].The EU’s AI Act,two and a half years in the making,was initially drawn up as a landmark bill to reduce harm in areas in which AI was thought to pose the biggest risks to people,such as in health care,education,and security,as well as banning uses that pose“unacceptable risks,”including manipulation of human behavior and evaluation of individuals’trustworthiness based on personal *** to the regulations,which will go into effect in stages over the next two years,“high-risk”AI systems will require risk-mitigation strategies,high-quality data sets,transparency,better documentation,and human *** most common current AI uses,such as augmenting recommendation engines and email spam filters,will see far less oversight.

关键词： email artificial transparency

Unprecedented Collaboration Plots Largest,Most Detailed Maps of the Brain

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Engineering 2024年第8期39卷 7-9页

作者： chris Palmer 不详

In October 2023,a set of 21 papers published simultaneously in the j.urnals Science,Science Advances,and Science Translational Medicine reported the largest,most-detailed maps to date of the cells making up portions of human and nonhuman primate brains[1,2].Accomplished by multiple large teams of neuroscientists in the United States and Europe,the collaborative effort also included the classification of 3300 different cell types in the human brain.

关键词： Medicine brains simultaneous

Increasing Threat of Scarcity Prompts Rise in Water Recycling

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Engineering 2024年第2期33卷 6-8页

作者： chris Palmer Senior Technology Writer

In j.nuary 2018,construction wrapped on Salesforce Tower(Fig.1),a 61-story office building that now dominates the skyline of San Francisco,CA,*** addition to being the tallest building in the city,Salesforce Tower is the largest structure in the world with an onsite water recycling *** by the Australian com-pany Aquacell(Milton,NSW,Australia),the system cleans 113 m^(3)of sewage,sink,shower,and other wastewater each day for use in irrigation and flushing toilets,saving an estimated 35000 m?of water anmually[1].The building is j.st one of dozens in San Fran-cisco outitted with their own water recycling systems,thanks to a city mandate enacted in 2015[1].

关键词： cycling wastewater recycling

Nearest Neighbor Sampling of Point Sets Using Rays

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Communications on Applied Mathematics and Computation 2024年第2期6卷 1131-1174页

作者： Liangchen Liu Louis Ly Colin B.macdonald Richard Tsai Department of Mathematics The University of Texas at Austin2515 SpeedwayAustinTX 78712USA Oden Institute for Computational Engineering and Sciences The University of Texas at Austin201 E24th StAustinTX 78712USA Department of Mathematics University of British Columbia1984 Mathematics RdVancouverBCV6T1Z2Canada

We propose a new framework for the sampling,compression,and analysis of distributions of point sets and other geometric obj.cts embedded in Euclidean *** approach involves constructing a tensor called the RaySense sketch,which captures nearest neighbors from the underlying geometry of points along a set of *** explore various operations that can be performed on the RaySense sketch,leading to different properties and potential *** information about the data set can be extracted from the sketch,independent of the ray *** integrals on point sets can be efficiently computed using the *** also present several examples illustrating applications of the proposed strategy in practical scenarios.

关键词： Point clouds Sampling Classification Registration Deep learning Voronoi cell analysis

Microglial dysfunction and genetic risk for neurodegenerative disease

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Neural Regeneration Research 2025年第5期20卷 1401-1402页

作者： Debra S.macdonald j.y Penney Department of Biomedical Sciences AVCUniversity of Prince Edward IslandCharlottetownPECanada

Neurodegenerative disorders such as Alzheimer's and Parkinson's diseases a re increasing in prevalence as world populations *** tremendous progress has been made,our understanding of the mechanisms that underlie the development of these diseases remains far from com *** troubling,despite the growing emotional and financial toll being to ken by neurodegenerative disorders,existing treatment options are limited almost exclusively to those that help manage symptoms but that lack the ability to alter the progression of the disease(Liu et al.,2022).

关键词： degenerative diseases

Experimental and analytical investigation on friction resistance force between buried coated pressurized steel pipes and soil

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Frontiers of Structural and Civil Engineering 2024年第4期18卷 615-629页

作者： Shaurav ALAM Tanvir MANZUR j.hn MATTHEWS chris BARTLETT Erez ALLOUCHE Brent KEIL j.hn KRAFT Department of Civil Engineering and Construction Engineering Technology Louisiana Tech UniversityRustonLA 71270USA Department of Civil Engineering Bangladesh University of Engineering and TechnologyDhaka 1000Bangladesh Georgia Tech Research Institute AtlantaGA 30332USA Stantec Inc. Edmonton T5J0K4Canada North West Pipe Company VancouverWA 98684USA

This paper presents an analytical approach for estimating frictional resistance to pipe movement at soil and external pipe surface of buried coated pressurized steel pipes relative to the internal thrust *** proposed analytical method was developed based on 36 experiments,which involved three coating types(cement mortar(CM),polyurethane type-I(PT-I),prefabricated plastic tape(PPT))on pipes’surfaces,three different soils(pea-gravel(PG),sand(S),silty-clay(SC)),and four simulated over burden depths above the pipe’s *** showed frictional resistance decreased with increasing over burden depth above the pipe’s *** degree of frictional resistance at the pipe-soil interface was found to be in the order of PG>SC>S for all coating variations and overburden *** coated pipe buried in all three types of soil produced significantly higher frictional resistance as compared to other coating *** on experimental data,the developed analytical introduced a dimensionless factor“Z”,which included effects of types of coatings,soil,and overburden depths for simplified rapid *** showed that the method provided a better prediction of frictional resistance forces,in comparison to previous analytical methods,which were barely close in predicting friction resistance for different coating variations,soil types,and overburden *** resistance force values reported herein could be considered conservative.

关键词： friction resistance force thrust force coated pressurized steel pipe soil type overburden depth