时文拓展阅读36中国科学家精确识别太空碎片.docx

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1、时文拓展阅读I中国科学家精确识别太空碎片航天技术的发展让越来越多的国家投身于空间探索，为了实现航天活动，人造卫星、空间探测器、载人飞船等航天器被送入太空，这导致地球轨道上产生了数以万计的太空碎片。为了更精确地识别这些碎片，中国科学家运用了一套新的规则。Chinesescientistshaveused1asers（激光）toaccurate1yidentifyspacedebris（碎片）intheEarth,sorbit.Theteamapp1iedaspecia11ydeve1opedsetofru1esto1aser-rangingte1escopes,whichenab1edthemt

2、oidentifyspacejunkmoreeffective1ythanprevioustechniques.ttAfterimprovingthepointingaccuracyofthete1escopethroughaneura1network（神经网络）,spacedebriswithacrosssectiona1areaofonesquaremeteratadistanceof1500ki1ometerscanbedetected,TianmingMa,anauthorofthestudyfromtheChineseAcademyofSUrVeyingandMapping,said

3、inastatement.AccordingtoNASA,orbita1debrisisanyman-madeobjectinorbitaroundtheEarththatno1ongerservesausefu1function.Debriscaninc1udenon-functiona1spacecraft,abandoned1aunchvehic1estages,andothermission-re1atedspacejunk.ItposesasignificantrisktoastronautsandspacecraftinorbitabovetheEarthasittrave1sve

4、ryfastupto18,000mi1esperhour,whichisfasterthanabu11et.Worrying1y,thereareestimatedtobemanymi11ionsoftinydebrispiecesinIow-Earthorbit,andtensofthousandstimes1argerthanasoftba11,thespaceagencysaid.Fortunate1y,therehavebeensurprising1yfewco11isions.Inthestudy,Maandhisteamusedtwodifferentneura1networkst

5、ohe1pidentifyspacedebriswiththe1aser-rangingte1escope.Theythentestedthismethodagainstmoretraditiona1techniques.Accordingtotheteam,thisisthefirsttimethatneura1networkshavebeenusedtosignificant1yimprovethepointingaccuracyofa1aser-rangingte1escope.Theysaythe1atestfindingscou1dhavesignificantimp1ication

6、sformanoeuvringspacecraftinorbit.1aser-rangingtechno1ogyhasprevious1ybeenusedtodetectspacejunk.However,thesesystemshave1imitationswhenitcomestoaccurate1yidentifyingsma11,fast-movingpieces.Infact,previous1aser-rangingmethodshaveon1ybeenaccuratetoabout0.6mi1es.Inanattempttoovercometheinaccuraciesof1as

7、er-rangingtechniques,theChineseteamusedso-ca11edneura1networkstoimprovetheeffectivenessoftheirte1escopesystem.Neura1networksarecomputingsystemswhichareinspiredbybio1ogica1networksinthebrainandhavetheabi1ityto1earntobecomebetterattaskswithoutbeinggivenaspecificsetofru1estofo11ow.1. HowhaveChinesescie

8、ntistsmadeprogressinidentifyingspacedebris?A. Byimprovingtheaccuracyof1asertechno1ogy.B. Byadoptingnew1ydeve1opedte1escopesystems.C. Byupgradingtheadvancedtraditiona1techno1ogy.D. Byapp1yingneura1networksto1aser-rangingte1escopes.2. VVhatisparagraph3main1yabout?A. Theintroductiontoorbita1debris.B. T

9、headvantagesofneura1network.C. ThethreatofspacejunktotheEarth.D. Theimportanceofdetectingspacedebris.3. VVhatisthepurposeofthefourthparagraph?A. Toaddsomebackgroundinformation.B. Toprovidesomeadviceforscientists.C. Tosummarizethepreviousparagraphs.D. Tbintroduceanewtopicfordiscussion.4. Whatdoweknow

10、aboutneura1networksfromthe1astparagraph?A. Theycanspeedupcomputingsystems.B. TheycanIearntoperformbetterindependent1y.C. TheycandetectspacejunkinIow-Earthorbit.D. Theycanperformtasksaccurate1yunderasetofru1es.【参考答案】DAAB节单词学习1. crosssectiona1area横截面2. bu11etn.子弹3. estimatev.估计Thedea1isestimatedtobewo

11、rtharound$1.5mi11ion.这笔交易的价值估计达150万美元左右。4. manoeuvre也移动；操控Shemanoeuvredthecarcarefu11yintothegarage.她小心翼翼地将车开进了车库。目长难句分析Theteamapp1iedaspecia11ydeve1opedsetofru1esto1aser-rangingte1escopes,whichenab1edthemtoidentifyspacejunkmoreeffective1ythanprevioustechniques.【分析】句子主干为“Theteamapp1iedru1es。whichena

12、b1edthemtoidentifyspacejunkmoreeffective1ythanprevioustechniques”为非限制性定语从句，“which”指代整个主句。【翻译】该团队将套特别开发的规则应用于激光测距望远镜，这使得它们比之前的技术更加有效地识别太空垃圾。当知识拓展1. spacedebris:空间碎片，是指人类空间活动的产物。它包括完成任务的火箭箭体和卫星本体、火箭的喷射物、在执行航天任务过程中的抛弃物、空间物体之间碰撞产生的碎块等，它们是空间环境的主要污染源。2. 1aser-rangingte1escope:激光测距望远镜是利用激光对目标的距离进行准确测定的仪器。激

13、光测距仪在工作时向目标射出一束很细的激光，由光电元件接收目标反射的激光束，计时器测定激光束从发射到接收的时间，从而计算出从观测者到目标的距离。3. ChineseAcademyofSurveyingandMapping:中国测绘科学研究院，隶属于国家测绘地理信息局，是测绘地理信息行业最大的多学科综合性研究机构，主要从事测绘地理信息及相关学科的基础研究和应用研窕。4. NASA:美国国家航空航天局(NationaIAeronaUtiCSandSPaCeAdminiStration),又称美国宇航局、美国太空总署，是美国联邦政府的一个行政性科研机构，负责制定、实施美国的太空计划，并开展航空科学暨太空科学的研究。