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saville wave介绍PPT最新版

能力（Talent）
个体认为自己能做什么或者擅长做什么

3、为什么要选择Saville Consulting Wave®？
③ 测试报告可提供丰富的测试信息，有助于对测试者进行评估，预测更准确。
c. 报告提供详细的胜任力潜能得分，有助于企业进行人岗匹配。

机是否一致？

Wave Professional Styles—专业报告
第三部分本次测试在 12 部分 -36 维度 -108 方面上的详细得分情况，包括每个维度的作答模式标注

Wave Professional Styles—专业报告
第四部分本次测试36维度上的得分及对比情况，包含每个维度的作答模式标注。
Saville Consulting Wave®
Saville 公司介绍
Saville 公司是世界最著名的测评内容供应商，由
原SHL集团创始人 Peter Saville 教授创建于2004年，
总部位于英国。
Saville公司根据个体职业发展周期，从个体
的能力、性格、动机、兴趣、岗位胜任力和与企
业文化适应性等角度出发，针对不同职业发展环
3、为什么要选择Saville Consulting Wave®？
③ 测试报告可提供丰富的测试信息，有助于对测试者进行评估，预测更准确。 d.提供丰富的企业文化及环境匹配度信息，协助用人企业更准确的进行人才筛选。
测试结果与企业文化紧
密联系，最大化的为企业人力资源管理与企业文化建设
提供支持。

单版报告
全方位测评报告企业环境匹配度报告全方位胜任力报告

3
为什么要选择Saville Consulting Wave®？

意大利savio自动络筒05年ORION PC参考说明

ORION主要数据的设置设定（齿轮图标）基本值系统所有各节主要工作数据辅助设备各节基本设定--单锭配置数据--单锭设定循环槽筒纱线张力传感器控制筒管操作参数防带状纱打结器空拈器技术参数1．基本值--机器名称----NETWORK--机器编号: 1 MACHINE IP ADDRESS机器序列号: 321-016-01 SUBNET MASK--打印机-- SERVER IP ADDRESS⊙无⊙ KF MACHINE NAME--每班结束时打印-- DOMAIN NAME⊙生产数据--CLEARER TYPE--⊙ NOT INTEGRATED〇 LOEPFE2．系统--语言-- 计量单位—支数--口令更改--中文（CHINESE） Nm Tex Nec New 级别 1 级别 2--日期--计量单位—长度-- 日期 / 时间 --YY/MM/DD 米 02/05/16 16：09：12计量单位—重量--计时器--公斤 00 ：003．所有各节锭数：60节数：1节序号：1第一锭：1末锭： 60--当前配置数据--节 1 ：1--604．主要工作数据--操作参数--防带状纱装置--张力传感器-- --循环--管纱输送器-- 纱线编码：COTTON Nominal Count：14.5--操作参数--筒纱重量（gr）：1500 筒纱长度（Mt）：110000管纱重量（gr）：58 管纱长度（Mt）：3150Real Count：14.5 络纱速度（Mt/min）：1200纱线数量：1 加速度：150滑动系数：1 上蜡装置（无：0；有：1）：0--防带状纱--筒纱直径参数：3333--张力传感器--最小压力：8压力：10 Anti-Wrap Sensitivity：220--VSS可变速系统参数--可变速系统百分比：100 减速最大速度：20--循环--管纱输送器----循环--反转速度：50 筒纱寻纱尾次数：2长疵反转速度：100 管纱更换次数：2管纱寻纱尾次数：25．辅助设备⊙左手机型〇右手机型--吸风装置类型----发送数据-- ⊙人工 TDE+变频器 Complete⊙ Motor Temperature Prob⊙ Overloading Motor〇Superba LinkYarn F. 管纱输送器落纱小车空管库筒纱传送带吸风装置除尘系统空管传送带筒纱传送带--筒纱传送带--传送带数量：0 转向器数量：0⊙机头⊙人工筒管传送带〇自动筒管传送带自动筒纱传送带上启动时所需筒纱数1：--吸风装置--⊙吸风电机⊙Magitex（意大利）停机时间（分钟）：2〇Electro-jet（西班牙）除尘间隔次数：0空管传送带--空管传送装置--传送带数量：1〇机头⊙机尾6．各节基本设定（只可查阅）--单锭配置数据--7．单锭设定⊙张力控制装置（Booster）〇筒纱架⊙纱线张力传感器〇 C.A.P. Full Step〇不允许更换管纱〇断纱改向〇 Lycra Cycle 〇包缠时DWM方式处理〇清纱器测试〇 Forced Bobbin Change （Red Light）〇 Forced Bobbin Change （Textile Alarm）--纱批----Yarn Feeler Sensor--⊙单批纱探纱传感器〇编码 1 ATX 1 BTSR 1〇编码 2 Sensor Value：70 注：①新式探纱传感器（与中探纱气阀一体）选择ATX1。

Dust Bowl 迷雾尘抉择时光说明书

Teaching the BookIn the midst of the Dust Bowl, with dust piling up like snow across the prairie, 14-year-old Billie Jo’s life is transformed by a terrible accident. It leavesher scarred—inside and out. Karen Hesse’s award-winning novel provides an unforgettable reading experience told in free verse against the backdrop of a desperate time in American history. Students will engage in activities including researching the history, geography, and art of the Dust Bowl.Theme Focus:Historical Fiction Comprehension Focus: Analyze Theme Language Focus: Dust Bowl Vocabulary Book SummaryIn powerful and lyrical free verse, Billie Jo Kelby tells the story of her life on the Oklahoma prairie from the winter of 1934 through the autumn of 1935—during the hard times of the Dust Bowl. Despite the constant dust storms and the struggle to make ends meet, Billie Jo is happy with her life. She loves to play the piano, her mother is pregnant with a much-wanted child, and her father is determined to keep their farm and home.Then a terrible accident brings tragedy into Billie Jo’s life. Her mother mistakes a pail of kerosene for water and pours it onto the stove. T rying to save her mother from the fire, Billie Jo accidentally makes things worse. After her mother and the baby die, Pa falls into a deep depression and Billie Jo can no longer play the piano because of the burns on her hands. Nor can she forgive her father or herself. Bil-lie Jo’s life is so painful, with her wound, her guilt, and the dust, that she tries to escape on a freight train. The journey results in Billie Jo’s own personal journey toward forgiveness and healing.Set against the backdrop of the Dust Bowl and the hardships faced by prairie families, the novel is a testament to the power of hope and the triumph of the human spirit.ABOUT THE AUTHORKaren Hesse was born in Baltimore, Maryland, in 1952. From an early age, she aspired to become an author, partly because of the encouragement of her fifth grade teacher. “Mrs. Datnoff believed I could be a professional writer some day and because she believed, I believed too.I love writing. I can’t wait to get to my keyboard every morning. Adults often ask why I write for the younger set. My reply: I can’t think of anyone I’d rather write for. Young readers are the most challenging, demanding, and rewarding of audiences.”In 1998, Hesse’s novel Out of the Dust won the Newbery Medal. It is based on extensive research into the history of the Dust Bowl and the people who survived it. Hesse has authored several other award-winning works of historical fiction on topics that range from World War II to the Holocaust. Karen Hesse currently lives in Vermont with her husband and has two grown daughters.Visit the Scholastic website for more information about Karen Hesse at: http://bit.ly/VUf9gq.BOOK STATSGrade Level Equivalent: 5–8 Ages: 11+ Genre: Historical Fiction, Free Verse Pages: 227Subject/Theme: Forgiveness, Survival, CourageGuided Reading Level: X OVERVIEWCommon CoreState StandardsReading Writing Listening &SpeakingLanguageGrade 5RL.5.1, RL.5.2,RL.5.4, RL.5.6W.5.3SL.5.1, SL.5.4L.5.4Grade 6RL.6.1, RL.6.2,RL.6.4, RL.6.6W.6.3SL.6.1, SL.6.4L.6.4Grade 7RL.7.1, RL.7.2,RL.7.4, RL.7.5W.7.3 SL.7.1, SL.7.4L.7.4Grade 8RL.8.1, RL.8.2,RL.8.3, RL.8.4,W.8. SL.8.1, SL.8.4L.8.4TEACHER GUIDE1© 2012 SI ALL RIGHTS RESERVEDGet Ready to ReadDust Bowl Provide students with a visual context for the dust storms to go with the dramatic and unreal descriptions in Out of the Dust. Fortunately, because the US government hired remarkable pho-tographers such as Walker Evans to document the storms and the people who suffered through them, there is a rich visual history available. Share these photographs, from the Kansas State University web-site, to show how humans and the landscape were ravaged by dust storms during the 1930s by visiting: http://bit.ly/WgzXPW.Before showing the photographs, share basic in-formation about the Dust Bowl. Consider discuss-ing how, by the 1930s, the soil in Oklahoma and neighboring states had become loose and dry partly as the result of converting too much wild grassland to farmland. Also consider sharing that wheat crops failed, and nearly 50 million acres were severely damaged before conservation measures helped put an end to the storms that threatened the lives of people and animals, as well as, the crops. Preview and Predict Discuss with students the title and cover of the book. Explain that the image on the cover is a picture of a real girl from the 1930s. In the novel, the girl is named Billie Jo, and she narrates her own story of survival during the Dust Bowl. Ask students what sort of challenges they think Billie Jo might face in the story.Words from the Dust Bowl Explain to students that the author uses some unfamiliar words that were part of people’s vocabulary during the Dust Bowl. She also uses words that describe the land-scape of the times. The list below contains words from the world of the Dust Bowl. Ask students to look for clues in the text to figure out the words’ meanings or to check dictionary definitions.Use Resource #1: Vocabulary Cards on page 7 and distribute copies to students. Ask them to write down the definitions of the words as they read them in the book.drought (p. 31) withered (p. 39) scorch (p. 81) sod (p. 107) duster (p. 109) parched (p. 128) migrants (p. 199) gaunt (p. 200)BIG QUESTIONCritical ThinkingHow will Billie Jo come “out ofthe dust”?As You ReadModeled Reading First, ask students to read the season and date on page 1: Winter 1934. Note that the book is divided into seasons from winter, 1934 to autumn, 1935. Then read aloud the first poem in the book. Explain that it is titled “Beginning, August 1920” because that is the date of Billie Jo’s birth, which she describes in the first poem. Model a fluent reading of the poem, being conscious of both the line breaks and the punctuation. Clarify any questions students have before they begin reading the book.Independent Reading Assign students to read Out of the Dust independently. Remind them to keep the big question in mind as they read.Analyze Theme Out of the Dust delivers a power-ful message about forgiveness, hope, and healing through its sparse, poetic text. Guide students to do a deep reading of the text, making inferences and analyzing the theme. Remind students that the theme is a message about life or human nature that the author expresses through the character’s actions and ideas.Ask students to think deeply about the themes of the book for themselves and to decide what message the book gives them. Emphasize the importance of supporting their interpretation of the theme with specific evidence from the text.Use Resource #2: Analyze Theme on page 9 to sup-port students in examining the themes in Out of the Dust. Ask them to answer the questions on the resource as they read and discuss their responses with a partner. When they have finished the book, ask them to state the theme of the book in one or two sentences. Guide a discussion about theme with the group, encouraging students to offer their answers and to supply evidence from the book to support their ideas.After Y ou ReadLead students in a discussion of these focus story elements.1. Historical Fiction 14-year-old Billie Jo tells this story. How does her point of view affect what you learn about life in the Dust Bowl? How would the story be different if an adult told it? (Sample answers: Billie Jo tells about how she dreams of playing the piano, tests she has in school, and her friends. An adult might talk more about money and farming.)2. Analyze Theme How have Billie Jo and her father healed by the end of the book? How has the land begun to heal as well? (Sample answer: BillyJo has finally forgiven herself and her father; she has healed inside, as well as, outside. Her father has also healed from the bitterness of losing his wife and is courting another woman. The land has healed from the dust storm and there is a rebirth of growing things.)3. Words from the Dust Bowl Use the words drought, parched, and gaunt to describe both the landscape of the Dust Bowl, Billie Jo, and her father. (Answers will vary, but should be supported by word meanings and text evidence.)Encourage students to share their responses with a partner or small group.1. Text-to-Self If you were Billie Jo, would you get off the train to return home or would you stay on to find a new life?2. Text-to-World The Dust Bowl was a natural di-saster. What natural disasters have occurred recently? How did they affect people’s lives?3. Text-to-Text What other young characters have you read about who have faced desperate conditions for survival? Compare one of the characters to Billie Jo.TEACHER GUIDE34 BIG QUESTIONCritical Thinking How will Billie Jo come “out of the dust”?Extension ActivitiesReading/Writing ConnectionPoetry to Prose Out of the Dust provides an op-portunity to teach students about the differences in writing genres. Ask students to choose one of their favorite poems in the book. Then challenge them to rewrite it in the form of a expository text like a newspaper article or a narrative text like a diary en-try. Help students to see the economy of poetry (the power of using few words) as they translate the genre into a prose form.Content Area ConnectionsHistory Letters to the White House Ask studentsto read letters that young people wrote to President Frank-lin D. Roosevelt and First Lady Eleanor Roosevelt during the Great Depression. They can find the letters by visiting: http://bit.ly/TtcRZi . Ask students to report back to the class by choosing a letter and reading it to the class. Then ask them to explain what it reveals about the times of the Great Depression.Geography Dust Bowl States Ask students toresearch the geographic area of the US that was affected by the Dust Bowl. Guide them to do an image search on “Dust Bowl maps,” to find several good maps of the affected areas and those hardest hit. Project a map of the United States on the whiteboard and have students draw in the states that were hit by the dust storms.Science Causes of the Dust Bowl Have studentsresearch the causes of the Dust Bowl, which are attributed to detrimental farming practices and climatic shifts. Ask them to report on their findings, citing the sources they read and explaining the theories behind the natural disaster.Art Photographs from the Dust Bowl Photog-raphers working for the US government captured historic images of the Dust Bowl and the people it affected. Encour-age students to examine these photographs on sites such as Wessel’s Living History Farm, which includes interviewD o n ’t f o r g e t t h etranscripts with people who lived through the Dust Bowl, as well as, photographs: http://bit.ly/UzKGHQ . Ask students to choose one photograph that they are especially drawn to and describe it to the class while projecting it on the white-board or a screen.BIG ACTIVITYFree Verse Poem After students have read Out of theDust , discuss things they notice and things they like about free verse. The book provides a wonderful example of the power of poetry to express deep feelings and meanings. Ask students to experiment with the form of free verse poetry to express something important in their lives by using the Big Activity: Free Verse Poem . Guide them through the following steps to create their poem:1. C hoose an experience from your life that has a special meaning to you.2. B rainstorm words and phrases that capture the feeling of the experience.3. C reate a rhythm and shape for the poem that grows out of your feelings.4. U se punctuation to guide the reader to stop and start at important places.5. W rite an ending line that emphasizes the theme of your poem.TEACHER GUIDE 5Name: ________________________________________ Date: ____________________BIG ACTIVITY: F ree Verse PoemChoose an experience from your life that has special meaning to you. Write a free verse poem about it, using words and phrases that capture the importance of the experience and your feelings. Give the poem a shape that expresses its meaning and write an ending line that emphasizes the theme.© 2012 SI ALL RIGHTS RESERVED Title: ___________________________________________________________Poem: ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________READ MORE AND LEARN MOREUse these books and other resources to expand your students’ study of the book or theme.Dear America: A Light in the StormKaren HesseAges: 9–13Grades: 4–7Lexile Measure: 850L Pages: 208Guided Reading Level: TIt’s 1861, the first year of the Civil War, and Amelia helpsher family run a lighthouse off the coast of Delaware, astate wedged between the warring North and South. Hermother and father argue constantly about President Lincolnand much more. Meanwhile, inspired by the lighthouse sheloves, Amelia comes to feel that she is the light of her family.Can she keep burning bright so that Father and Mothercome back together? Available as a Storia e-bookAntarcticaWalter Dean MyersAges: 11–14Grades: 6–8Lexile Measure: 1100L Pages: 144Guided Reading Level: YExploring the treacherous South Pole was never easy, buta few brave men, such as James Cook, Richard Byrd, andErnest Shackleton, were determined to do it. The authordescribes their journeys in riveting detail while portrayingthe strength and courage it took to face such unforgivingconditions. Available as a Storia e-bookThe Healing SpellKimberly Griffiths LittleAges: 10–14 Grades: 5–8Lexile Measure: 800L Pages: 368T welve-year-old Livie is living with a terriblesecret: she caused the accident that left her Mamma in acoma. When Mamma comes home from the hospital, stillin a coma, Livie is wracked by guilt. Can a mysterious faithhealer with a magical box of spells help Livie make Mammawake up again? Is a healing string Livie’s last chance forforgiveness? Available as a Storia e-bookTo find PDF versions of the Storia teacher guidesand links to purchase the related books, visit:/ereading-resources/Morbito 2: Guardian of the DarknessNahoko UehashiAges: 11–13 Grades: 6–8Lexile Measure: 830L Pages: 272Now an adult, Balsa must return to the capitalshe fled as a child to clear the name of her mentor, Jiguro,and unravel the mystery of her past. One secret from thepast puts Balsa in mortal peril. She discovers that Jigurowas once a member of the king’s royal guard, and when heescaped with Balsa, the king sent his guards out one by oneto bring them back. Are the Guardians of the Dark still afterher? By returning to the capital, is she walking right intotheir hands? Available as a Storia e-bookWar HorseMichael MorpurgoAges: 10–14 Grades: 5–8Lexile Measure: 1090L Pages: 192Guided Reading Level: ZJoey is a handsome red bay horse, loved by Albert, his13-year-old master. When Albert’s father sells Joey to theBritish Army, the horse is carried away by strangers, trainedto serve in combat, and shipped to the battlefields of WorldWar I. Hunger, cold, and the sound of great guns are nomatch for Joey’s bravery and sense of compassion. He iscertain that someday he will return home, even though heis captured by the enemy. Will Joey ever make it back to thefarm and Albert? Available as a Storia e-bookCircle of SecretsKimberley Griffiths LittleAges: 10–14 Grades: 5–8Lexile Measure: 800L Pages: 336Shelby has a pain in her heart that’s been thereever since her mama, Mirage, left a year ago. When herdaddy takes a job overseas, Shelby has to go live with Miragetill after Christmas. There’s a blue-bottle tree in the Mirage’syard, which is supposed to trap spirits and keep things safe.Shelby thinks that a ghost may be leaving messages in thebottles. Now, Shelby needs Mirage more than ever, and itseems like forgiveness is the real key to putting everyone’sghosts to rest. Available as a Storia e-book6 TEACHER GUIDETEACHER GUIDE 7© 2012 SI ALL RIGHTS RESERVEDResource #1: Vocabulary CardsName: ________________________________________Date:____________________RESOURCE #2:A nalyze ThemeAnswer these questions as you read to analyze the theme of the book. Provide evidence fromthe text to support each of your answers.“Beginning: August 1920” (pp. 3–5)1. How does Billie Jo think her father feels about her being born a girl?“Blame” (pp. 70–72)2.W hat does Billie Jo think about the accident? How does she feel about herself? How doesshe feel about her father right after the accident?“Outlined by Dust” (pp. 111–114)3. What mixed feelings does Billie Joe have for her father? How does he treat her?“Midnight Truth” (pp. 195–196)4. What are Billie Jo’s feelings about her father now? What does she plan to do about it?“Cut it Deep” (pp. 209–211)5. H ow have Billie Jo’s feelings toward her father changed? How have her feelings aboutherself changed?What do you think is the theme or message about life in Out of the Dust?8 TEACHER GUIDE© 2012 SI ALL RIGHTS RESERVED。

Vanity Fair打印

Vanity Fair 名利场
A Novel without a Hero
I. Introduction to the Author
William Makepeace Thackeray (1811—1863)
Author:Thackeray’s Life
Time
1811
6 years 1830
Comments on Thackeray
He is one of the greatest critical realists of the 19th century. He took it as his duty to expose the vices and to disclose the darkness of society. He also regarded snobbery and the money-grabbing as the chief vice in the society. He criticized the social moral by speaking in an ironical(讽刺的), sarcastic(尖刻的) and cynical(愤世嫉俗的) tone of an on-looker.
Precise language Thorough observation Rich knowledge of social life and human sympathy Accurate and true to life A satirist His satire is caustic(刻薄的) and full of subtle humor. A moralist He intends to let his readers get a moral impression.

怀念威廉·科恩劳尔的尼瓦达银腾打印目录与检查表

Aladdin on Carpet
Las Vegas
Year Guide
MM .999 Released Price
CC Rim 1994 $22-$28
(V) Ali Baba (3 Dots)
Aladdin on Carpet
CC Rim 1994 $100-150
Sinbad
Aladdin on Carpet
$18.00 $15.60
$17.00
$22.75
Approx
2019
2020 Silver
Auction Auction Weight
$18-$25 $16-$20 .6010 Oz
.4898 Oz
$16.50 $25.00 .4948 Oz
$16-$20 $20.00 .5881 Oz
$15-$25
Monorail
Bally's (3 7s)
GDC Rim 1995 $22-$28
Running 7 (LV Top)
Bally's (3 7s) (LV Top)
GDC Rim 1995 $22-$28
(E) Running 7(WR)(LV NV.Bottom) Bally's (3 7s) (LV Top)
Reno
MM .999
G Rim
Year Guide Released Price
1996 $22-$28
Toucan/Angel Fish
Atlantis Hotel Tower
G Inner 1998 $22-$28
(E) Toucan/Angel Fish(50++)
Atlantis (Many Blds) (WL)

英语重点词汇详解savior

英语重点词汇详解saviorsavior英[ˈseɪvjə]美[seɪvjər]n.救助者；挽救者；救星；救世主复数：saviors英文释义：1.a teacher and prophet born in Bethlehem and active in Nazareth; his life and sermons form the basis for Christianity (circa 4 BC - AD 29)教师和先知出生在伯利恒，活跃在拿撒勒；他的生活和布道构成了基督教的基础(大约公元前4年-公元29年)2.a person who rescues you from harm or danger把你从伤害或危险中解救出来的人举个例子：1.I wanted nothing more than to be alone with my perpetual savior.我什么也不想要，只想和我永远的救星待在一起。

2.After all he was your savior. (9KB)再说他还是你的救命恩人。

3.We must admit, "I need a Savior." (12KB)我们必须承认，“我需要一位救赎者。

”4.Harry Stunned the Death Eater as they passed. Malfoy looked around, beaming, for his savior, and Ron punched him from under the Cloak.马尔福惊喜地看向四周，找着他的救星，罗恩隔着隐形衣戳了他一下。

常用短语：The Savior: 救世主Anticipating the Savior: 期待救世主Christ the Savior Cathedral: 救世主大教堂词汇拓展：近义词n. Son, Word, Logos, Jew, Hebrew, Israelite, prophet 联想词hero英雄;salvation拯救;god神;scapegoat替罪的羔羊;Jesus耶稣;deity神;nemesis报应;godfather教父;redemption赎回;miracle奇迹，奇迹般的人或物;almighty全能的;compendium英[kəmˈpendiəm]美[kəmˈpendiəm]n.概要；概略；收集物；汇编；用具盒；书信用品夹复数：compendiumscompendia英文释义：a collection of facts, drawings and photographs on a particular subject, especially in a book某一特定主题的事实、图画和照片的集合，尤指在书中举个例子：1.a compendium of advertisements and reviews, interlarded with gossip.一份登载广告和评论的小集子，其中夹杂着一些小道传闻。

0. FIBONACCI NUMBERS

1
h=4
Z4
H4= S4
h=5 Z5 H5= S5
Z6 h=6
S6
H6
Figure 1: The ﬁbonacenes with four, ﬁve, and six hexagons; cf. Fig. 3. Deﬁnition 1. A hexagonal system is a connected plane graph without cut-vertices in which all inner faces are hexagons (and all hexagons are faces), such that two hexagons are either disjoint or have exactly one common edge, and no three hexagons share a common edge. Deﬁnition 2. A hexagonal system is said to be simple if it can be embedded into the regular hexagonal lattice in the plane without overlapping of its vertices. Hexagonal systems that are not simple are called jammed . Hexagons sharing a common edge are said to be adjacent or neighboring . Two
When reading a book or an article in which Fibonacci numbers are encountered, one should always check the way in which these are deﬁned. Some authors use the initial conditions F0 = F1 = 1 , and thus their “Fibonacci numbers” are shifted by one relative to the present ones. 2 In view of some recent disputes concerning the spelling of the name, it may be useful to repeat Balaban’s original words from [3]: We are aware that ﬁbonaccenes would be etymologically more suitable but we suppressed one c for the simplicity and for similarity with the established name “acenes”.

SAVIOXCL 电器图纸

吸风电机过载保护
车头CPU输出
230VAC 供电
主电机启动
紧急停车
主电机运转
车头CPU输入
吹吸风装置启动接触器黄电清
电脑
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Luo et al[1].2008-3P

Size variation of conodont elements of the Hindeodus –Isarcicella clade during the Permian –Triassic transition in South China and its implication for mass extinctionGenming Luo a ,Xulong Lai a ,⁎,G.R.Shi b ,Haishui Jiang a ,Hongfu Yin a ,Shucheng Xie c ,Jinnan Tong c ,Kexin Zhang a ,Weihong He c ,Paul B.Wignall daFaculty of Earth Science,China University of Geosciences,Wuhan 430074,PR ChinabSchool of Life and Environmental Sciences,Deakin University,221Burwood Hwy,Burwood VIC 3125,Australia cKey Laboratory of Geobiology and Environmental Geology,China University of Geosciences,Wuhan 430074,PR China dSchool of Earth and Environment,University of Leeds,Leeds.LS29JT,United KingdomA B S T R A C TA R T I C L E I N F O Article history:Received 17August 2007Received in revised form 1April 2008Accepted 3April 2008Keywords:Multi-episode mass extinction ConodontHindeodus -Isarcicella Size reductionPermian –Triassic transition South ChinaBased on the analysis of thousands of conodont specimens from the Permian –Triassic (P –T)transition at Meishan (the GSSP of P –T Boundary)and Shangsi sections in South China,this study investigates the size variation of Hindeodus and Isarcicella P1elements during the mass extinction interval.The results demonstrate that Hin-deodus –Isarcicella underwent 4episodes of distinct size reduction during the P –T transition at the Meishan Section and 2episodes of size reduction in the earliest Triassic at Shangsi.The size reductions at Meishan took place at the junctions of beds 24d/24e,25/26,27b/27c and 28/29,and at the junctions of beds 28/29c and 30d/31a at Shangsi.The two earliest Triassic size reduction episodes were correlative between the two sections.These changes coincide with some important geological events such as eustatic sea-level changes,anoxic events,carbon isotope oscillations,miniaturization of brachiopods and microbial changes.Through detailed investigation of the palaeoenvironment and the palaeoecology of Hindeodus –Isarcicella ,the authors propose that the main causes of the size reduction was a sharp decline of food availability because of the mass extinction and the anoxic event during the P/T transition.The pattern of size reduction supports suggestions that the end-Permian mass extinction was multi-episodal,consisting of 3extinction events rather than a single catastrophic event.©2008Elsevier B.V.All rights reserved.1.IntroductionThe end-Permian biotic crisis was the largest mass extinction in the fossil record.It eliminated over 90%of species in the oceans (Stanley and Yang,1994;Bambach et al.,2004)and about 70%of vertebrate families on land (Benton,1988;King,1991;Maxwell,1992).The cause or causes and duration as well as the nature of the extinction remain uncertain and actively debated (Wu and Liu,1991;Wignall and Hallam,1993;Isozaki,1997;Kozur,1998;Yin and Tong,1998;Jin et al.,2000;Yin et al.,2001;Wang and Cao,2004;Fang,2004a,b;Grice et al.,2005;Racki and Wignall,2005;Yin et al.,2007a ).The Global Stratotype Section and Point (GSSP)of the Permian –Triassic Boundary at Meishan in Zhejiang Province,China has served as a focal point in this global debate,as it has provided much critical stratigraphical and palaeontological data.As a result,the section has received intensive multidisciplinary studies by various research groups,including lithostratigraphy,biostratigraphy,sedimentology,sequence stratigraphy,isotope geochemistry,eventostratigraphy,and magnetostratigraphy (Yin et al.,2001and references therein).There are several opinions about the causes and patterns of the P –T mass extinction (Isozaki,1997;Kozur,1998;Wang and Cao,2004;Fang,2004a,b;Grice et al.,2005;Racki and Wignall,2005).Some authors have proposed a single-episode catastrophic mass extinction (Jin et al.,2000;Kaiho et al.,2006),while others have argued for a multi-episode mass extinction (Wu and Liu,1991;Wignall and Hallam,1993;Yin and Tong,1998;Fang,2004a,b;Xie et al.,2005;Shen et al.,2006;Yin et al.,2007a ).In this paper,we attempt to test these various scenarios by using the size variation data of a group of conodont species from a single clade from several continuous Permian –Triassic boundary sections in South China.The fundamental question addressed in the study is to see if the sizes of conodont species varied across the PTB and,if so,whether or not the timing of the signi ﬁcant size changes actually corresponded to any of the proposed PTB extinction intervals.A related question,also investi-gated as an integral part of this study,is to elucidate the possible cause (s)for the size change of the conodont species across the PTB.There is now a considerable literature relating size variation in lineages through time to biotic crises caused by environmental changes in earth history.Initially,Urbanek (1993)coined the term “Lilliput effect ”for an observed size reduction of Silurian graptolites during a biotic crisis.Subsequently,other researchers have reported similar size decreases during times of extinction;for example,the sizePalaeogeography,Palaeoclimatology,Palaeoecology 264(2008)176–187⁎Corresponding author.Faculty of Earth Sciences,China University of Geosciences,Wuhan,Hubei 430074,PR China.Tel.:+862767883139;fax:+862787515956.E-mail address:xllai@ (X.Lai).0031-0182/$–see front matter ©2008Elsevier B.V.All rights reserved.doi:10.1016/j.palaeo.2008.04.015Contents lists available at ScienceDirectPalaeogeography,Palaeoclimatology,Palaeoecologyj o u r n a l h o me p a g e :w w w.e l sev i e r.c o m /l oc a t e /pa l a e oof late Devonian conodonts (Girard and Renaud,1996),heart urchins across the Cretaceous/Tertiary boundary (Jeffery,2001),and various organisms around the Permian/Triassic boundary (Twitchett,2001;He et al.,2005;Twitchett,2005a,b;Luo et al.,2006;Twitchett,2006;He et al.,2007;Twitchett,2007).It is widely held that there was no obvious change in conodont fortunes during the end-Permian mass extinction,because many conodont lineages clearly survived through the PTB (e.g.Clark et al.,1986;Jiang et al.,2007).However,the survival of lineages tends to overlook the potential ecological information that can come from the study of large conodont samples.Furthermore,unlike most other organisms,most Late Permian conodont species or their lineages persisted through into the Lower Triassic.Therefore,these conodonts can serve as the best material for the study of the size variation during the P –T transitional period.Luo et al.(2006)reported a size reduction in P1elements of the conodont genus Neogondolella at the bed 24d/24e junction (Upper Permian)at Meishan.However,the limited Neogondolella specimens from the Lower Triassic did not allow us to perform a full-scale size variation study throughout the Permian –Triassic transition.To overcome this shortfall,in this paper wehaveFig.1.A:Location map of study area in South China;Meishan Section (B)and Shangsi Section (C).(after Wingnall et al.,1995and Jiang et al.,2007).Table 1The total number,mean size,standard deviation,percentage of specimens larger than 0.5mm and 95%con ﬁdence interval of the mean for the P1element of Hindeodus –Isarcicella from the P/T transition at the Meishan Section,Changxing,Zhejiang Province Bed24a 24b 24c 24d 24e 252627a 27b 27c 27d 2829Number 793957717289413314127017147Mean (mm)0.4580.4590.4430.5340.4360.5330.3920.4550.5030.4210.4670.5800.459Standard deviation 0.1320.1430.0790.0960.1000.0060.0430.0980.1080.1030.1580.1500.108Percentage (N 0.5mm)29.1133.3320.0076.6225.5310027.6647.3718.4434.4467.8438.3095%con ﬁdence interval of the mean0.49130.49890.70020.56100.49510.58380.40480.47250.51820.43720.48710.60080.49260.42440.40260.18310.51440.35950.48220.36190.42980.48110.40170.44720.55360.4264177G.Luo et al./Palaeogeography,Palaeoclimatology,Palaeoecology 264(2008)176–187chosen hindeodid conodonts because as a lineage they survived across the P–T boundary.The recovery and size measurement of abundant conodont specimens is time-consuming,and this kind of study has only previously been undertaken for the P–T transition(Luo et al., 2006).The present paper examines the size variations,in large samples,of conodonts from the Hindeodus–Isarcicella clade duringtheFig.2.Size distribution histogram of P1elements of Hindeodus–Isarcicella from each bed in ascending order(24a to29except for bed25)through the P/T transition at the Meishan Section A.Theﬁgures above each histogram are the total number of specimens in each size range.178G.Luo et al./Palaeogeography,Palaeoclimatology,Palaeoecology264(2008)176–187end Permian to earliest Triassic interval,with the aim of improving our understanding of the mass extinction patterns and of biotic recovery.2.Material and methodThirteen successive bulk samples ranging from bed24to bed29 (the PTB is sited at the bottom of bed27c)were collected from Section A at Meishan,Changxing,Zhejiang province(Fig.1).The sample from bed24was divided into5sub-beds(beds24a–e).Bed27was also evenly separated into4sub-beds(beds27a–d).Each of these13 samples weighed20kg.The clay samples collected from beds25and 28were processed directly by water.The other samples were crushed into1cm3size fragments and treated with dilute acetic acid(10%)to dissolve the samples.A 2.80–2.81g/ml gravity liquid made of bromoform(2.89g/ml)and acetone(0.79g/ml)was used in the conodont separation for all the samples.The conodonts were picked one by one under the binocular stereoscope.All the Meishan samples have been entirely processed over20months.The samples from the Shangsi Section have not been completely processed but in the earliest Triassic there are Hindeodus–Isarcicella elements for this work.Over20,000specimens were obtained from this processing.Among these,more than14,000were P1elements of Neogondolella,Hindeodus and Isarcicella,which are important elements during the P/T transition.A binocular stereoscope and micrometer were used to measure the length between the anterior and posterior ends of each well-preserved Hindeodus–Isarcicella P1element.First,the complete elements with both anterior and posterior parts were measured under the binocular stereoscope with the micrometer in the ocular.Secondly,each measured element was arrayed according to its size recorded in the notebook. Thirdly,the size of some randomly-chosen elements was measured and compared to the measurements obtained from theﬁrst step and found to be nearly the same.Finally,different personnel were employed to measure some of the randomly chosen elements(about30–40elements of each bed)and compared their measurements with those of theﬁrst person,and again both results were found to be nearly the same.The mean size,distribution histogram,standard deviation and95% conﬁdence interval of the mean size were used to analyse the size distribution and variation of the conodonts.The mean size(X),which reﬂects the condition of a community,is based on the following equation:X¼1=N4X Ni¼1liwhere X is the mean size,N is the number measured in each bed and li is the length of each element.The95%conﬁdence interval,reﬂecting whether the size reduction is credible on95%conﬁdence,is based on the following equation:Y¼t a=2SﬃﬃﬃﬃNpwhere Y is theﬂuctuating range,t a=2is the t-test value of1−αconﬁdence,S is the standard deviation and N is the number measured from each bed.So,the conﬁdence interval is(X−Y,X+Y),where X is the mean size,X−Y is the lower line,while X+Y is the upper line.3.Taxonomy and evolution of Hindeodus–IsarcicellaBoth hindeodid and isarcicellid P1elements are scaphate,with a robust cusp at the anterior and numbers of smaller denticles following the cusp.The hindeodid P1elements are symmetrical or slightly asymmetric,whilst the isarcicellid P1elements are extremely asymmetric.The cavity of hindeodid shows slight swelling but no thickening,whilst that of isarcicellids is both swollen and thickened. Some of the isarcicellid P1elements have a denticle or series of denticles on one side or both sides of the cavity surface.Interpreta-tions of the evolution of the hindeodid–isarcicellid lineage are controversial(Kozur,1996;Ding et al.,1997;Lai,1997;Wang and Wang,1997).Ding et al.(1997)thought that Hindeodus latidentatus–H. parvus–Isarcicella turgida–I.isarcica formed an anagenetic lineage. However,Wang and Wang(1997)replaced I.turgida with I.staeschei in the evolutionary sequence of(Ding et al.,1997).Nevertheless, almost all authors have accepted the idea of an evolutionary sequence from hindeodid to isarcicellid.Nicoll et al.(2002)proposed that the growth pattern of hindeodids occurred by the addition of denticles at the posterior.The length between the anterior and posterior is therefore an important size parameter for Hindeodus–Isarcicella.During the past two decades,the P–T conodonts at the Meishan section have received intensive studies(Lai et al.,1995;Zhang et al., 1995;Ding et al.,1997;Wang and Wang,1997;Mei et al.,1998).Based on large conodont samples,our group has established parallel gondolellid and hindeodid zones at this section(Jiang et al.,2007), and the hindeodid zones in ascending order are tidentatus zone, H.praeparvus zone,H.changxingensis zone,H.parvus zone,Isarcicella staeschei zone and I.isarcica zone from beds24a to29.According to the latest radiometric dates,the absolute age of bed28at the Meishan Section(GSSP)is250.7±0.3Ma,and that of bed25(white clay)is 251.4Ma(Bowring et al.,1998).Mundil et al.(2004)rectiﬁed their earlier data(Mundil et al.,2001),and suggested that the duration of the mass extinction was shorter.In any case,the duration from bed25 to28is about0.7million years.This0.7myr interval corresponds to4 hindeodid conodont zones and hence indicates that the evolutionary rates were high for the conodonts.4.Size variation in the Hindeodus–Isarcicella clade4.1.Data from the Meishan sectionThe number(all the complete elements from each bed),mean size and standard deviation of P1elements of Hindeodus–Isarcicella for each bed are shown in Table1,together with the95%conﬁdence interval of the mean and the percentage of Hindeodus–Isarcicella P1 elements larger than0.5mm.The size distribution within each bed is shown in Fig.2.The mean size of all the individuals within a community which can more precisely reﬂect the living environment of this community is shown in Fig.3,of which the shadow interval shows the95%conﬁdence interval of the mean.The dominant peak for bed24a is0.4–0.5mm,with element length showing a normal distribution(Fig.2).The dominant peak for bed24b is0.3–0.4mm,but with a marked right-skewed distribution (skeweness=0.3112).The dominant peak for bed24c is also0.4–0.5mm,with a normal distribution,although with fewerelements.Fig.3.Variation of the mean size of P1elements of Hindeodus–Isarcicella from the end Permian(bed24a)to early Triassic(bed29)at the Meishan Section.The black area is the 95%conﬁdence interval of the mean size,and the central white circle and line show variation of the mean size.179G.Luo et al./Palaeogeography,Palaeoclimatology,Palaeoecology264(2008)176–187The dominant peak for bed 24d is 0.5–0.6mm,and it also appears to have a normal distribution.The dominant peak for bed 24e is 0.4–0.5mm,with a marked left-skewed trend.Both the two elements of bed 25are larger than 0.5mm,while the elements of bed 26are 0.3–0.5mm,with no element larger than 0.5mm.The dominant peaks for bed 27a and 27b are within 0.4–0.5mm,and their distribution approaches a normal distribution.The dominant peaks for bed 27c and 27d are 0.3–0.4mm,with slight right skew.The dominant peak for bed 28is 0.5–0.7mm,while that for bed 29is 0.4–0.5mm.Fig.3shows the size variation of conodont Hindeodus-Isarcicella P1element from the end Permian (bed 24a)to earliest Triassic (bed 29).The black area stands for the 95%con ﬁdence interval of the mean,and the central white points and line of the area show the variation of mean size of specimens in each bed.As the graph (Fig.3)shows,during the transitions between beds 24e/24d,26/25,27c/27b and 29/28,the characters (mean size,dominant peak,percentage)of size variation exhibit distinct changes.The dominant peak and the mean size for bed 24d are 0.5–0.6mm and 0.534mm respectively,and the percentage with a size larger than 0.5mm is 76.62%,while these characters for bed 24e are 0.4–0.5mm,0.436mm and 25.53%,respectively.The 95%con ﬁdence interval of the mean size shows that the upper line of bed 24e (0.4951)is smaller than the lower line of bed 24d (0.5144),so the size reduction is credible at a 95%con ﬁdence level.The t -test for means shows that the size reduction was distinct (p =0.000).There are only two Hindeodus –Isarcicella P1elements in bed 25,both of which are larger than 0.5mm,with a mean size of 0.533mm,while in bed 26all the elements are less than 0.5mm,and the mean size is only 0.392mm.The t -test for means (p =0.002)indicates the size variation was signi ﬁcant.Also,the size reduction in bed 26is credible as shown by the 95%con ﬁdence interval of the mean shown in Table 1.In beds 27and 28,Hindeodus –Isarcicella replaced Neogondolella as the dominant genera.There are abundant Hindeo-dus –Isarcicella P1elements in these beds.Jiang et al.(2007)identi ﬁed three assemblages from the end Permian (bed 24a)to the earliest Triassic (bed 29)by comparing the ratio of Hindeodus –Isarcicella P1elements to the Neogondolella P1elements,and beds 27and 28belong to their second assemblage.In bed 27b,the dominant peak and themean size are 0.4–0.5mm and 0.503mm,and the percentage with a size larger than 0.5mm is 47.37%,while in bed 27c,the dominate peak and the mean size are 0.3–0.4mm and 0.421mm respectively,and the percentage of size larger than 0.5mm is 18.44%.The upper line (0.4372)of the 95%con ﬁdence interval of the mean at bed 27c is smaller than that of the lower line (0.4811)at bed 27b.The t -test for means (p =0.000)indicated that this reduction of size was undoubted.In bed 27d,the dominant peak is 0.3–0.4mm,the same as bed 27c,but the mean size is 0.467mm,and the percentage with a size larger than 0.5mm is 34.44%.The mean size in bed 28,where the largest specimens in these beds are found,is 0.580mm,the dominant peak is 0.5–0.6mm,and the percentage with a size larger than 0.5mm is 67.84%.However,in bed 29,the dominant peak and mean size are 0.4–0.5mm and 0.459mm,respectively,and the percentage with a size larger than 0.5mm is 38.30%.At the transition between these two beds,all the parameters vary distinctly,and the upper line (0.4926)of the 95%con ﬁdence interval for bed 29is much smaller than the lower line (0.5536)for bed 28.t -test for means shows no reason to believe that the size reduction was not signi ﬁcant (p =0.000).It is interesting to note that the size of P1elements of Hindeodus –Isarcicella in beds 25and 28is comparatively very large,especially in bed 28(see above).Both of these are clay beds,and previous workers have thought that the extinction took place at these levels (Fang,2004a,b;Xie et al.,2005).In order to determine whether or not the size variation of Hindeo-dus –Isarcicella populations was affected by the presence of different species,we investigated the size variation of a single species,Hindeodus typicalis ,from beds 24a to 24e.This reveals ﬂuctuations similar to those shown by the overall population of conodonts,with a peak size in Bed 24d and a marked reduction in Bed 24e (Fig.4).t -test for means shows that the size reduction during this transition was signi ﬁcant (p =0.007).4.2.Data from the Shangsi sectionTable 2,Figs.5and 6show the size variation of P1elements of Hindeodus –Isarcicella and Hindeodus from the Shangsi Section,Sichuan Province.The ﬁrst change was recognized in thetransitionFig.4.Variation of the mean size of P1elements of Hindeodus typicalis from the end Permian (bed 24a to bed 24e)at the Meishan Section.The black area is the 95%con ﬁdence interval of the mean size,and the central white circle and line show variation of the mean size.Table 2The total number,mean size,standard deviation and 95%con ﬁdence interval of the mean of specimens of the P1element of Hindeodus-Isarcicella of earliest Triassic age from the Shangsi Section,Guangyuan,Sichuan Province Bed28c 28d 29a 29b 29c 30(b +c)30d 31a 31b 3233Number 1111247732104411915Mean(mm)0.3550.4310.1940.3390.3130.3900.4020.3480.3640.3430.455Standard deviation0.05100.0660.0440.1050.0660.0780.1140.0620.13195%Con ﬁdence interval of the mean0.39490.36300.35380.46810.42560.36310.40040.37350.52770.32720.30430.27310.31230.37830.33290.32770.31340.3829Fig.5.Variation of the mean size of P1elements of Hindeodus –Isarcicella from the earliest Triassic of the Shangsi Section,Sichuan Province.180G.Luo et al./Palaeogeography,Palaeoclimatology,Palaeoecology 264(2008)176–187between beds 29c and 28(combined beds 28c and 28d)in the Hin-deodus parvus zone (Lai et al.,1996).The upper line (0.3538)of the 95%con ﬁdence interval of the mean size of bed 29c is larger than the lower line (0.3272)of bed 28,while the upper line of the 75%con ﬁdence interval of the mean size of bed 29c (0.3321)is smaller than that of the lower line of bed 28(0.3381),and the t -test for means (p =0.021)also shows there is no reason to doubt this size reduction..The second size change was during the transition between bed 30d and 31a,in the I.isarcica zone.The upper line (0.3631)of the 95%con ﬁdence interval of the mean size of specimens in bed 31a is smaller than the lower line (0.3783)for bed 30d.So,the size reduction of this episode is credible at a 95%con ﬁdence level,and the t -test for means (p =0.001)also supports this phenomenon.As in the Meishan section,these data show that conodont size underwent two-episodes of reduction at the Shangsi section during the earliest Triassic.A comparison of the mean sizes of elements in these two sections shows that the mean size of hindeodid conodonts from the Shangsi Section is smaller than that of the Meishan Section.There is no reason to doubt that the difference in mean size is creditable as shown by a t -test of the means (p =0.000).This difference in means size between the two sections will be discussed below.5.DiscussionThe genera Hindeodus and Isarcicella survived the P –T mass extinction and then ﬂourished in the earliest Triassic.Taxonomically,both genera present no obvious change after the major extinction events during the P –T transition.However,the Hindeodus –Isarcicella populations show several episodes of size reduction of P1elements in this interval.As shown in Fig.3–6,from the latest Permian to earliest Triassic the mean size of P1elements of Hindeodus –Isarcicella remained nearly the same except for the several times when they experienced obvious size reductions.If the size changes are evidence of biotic crisis (Girard and Renaud,1996;Schmidt et al.,2006;Twitchett,2007),it would indicate that there were several crises that affected the growth of the conodonts in the P/T transition period.Normally,it is dif ﬁcult to distinguish juvenile hindeodids from small adult elements (Dr.Robert Nicoll,personal communication 2006).However,the texture and the thickness of the cavity are different in the juvenile and adults.The cavity of the juvenile is thin and translucent,whilst that of the adult is thick and ing this criterion,we interpret the size reductions of Hindeodus –Isarcicella elements in our study to be indicative of populations with a higher proportion of juveniles.The evolutionary rate of the hindeodid –isarcicellid clade through the PTB interval is very high,re ﬂecting a rapidly changing environment.In this sense,these conodonts did respond to the P –T mass extinction.The temporal pattern of the conodont size variation is also coincident with someother important geological events such as an anoxic event,sea-level changes and carbon isotope oscillations (Fig.7).5.1.Palaeoecology of conodont Hindeodus –IsarcicellaThe palaeoecology of Hindeodus and Isarcicella is still controversial.There are two main views:one viewpoint considered Hindeodus –Isarcicella to be a near-shore,shallow water taxon (Clark,1974;Wardlaw and Collinson,1984;Tian,1993;Hirsch,1994;Baud,1996;Krystyn and Orchard,1996;Orchard,1996);the other supposed that Hindeodus –Isarcicella had a wide facies range and occurred both in shallow and deeper water environments (Behnkn,1975;Clark,1981;Zhang,1990;Kozur,1995,1996;Kozur,1998).Kozur (1995)also pointed out that Hindeodus shows no provincialism and straddles the P/T boundary and is therefore the most suitable genus for de ﬁning the P/T boundary within a phylomorphogenetic line.Lai et al.(2001)and Lai and Zhang (1999),based on the evolution of Hindeodus –Isarcicella and Clarkina (Neogondolella ),and on palaeoen-vironmental interpretations of the Meishan D Section,concluded that Hindeodus was pelagic,found in sediments deposited at different depths,but living in the top layer of the ocean water.They also suggested that the replacement of Clarkina by Hindeodus was caused by the development of anoxic bottom waters during the Permian –Triassic transition and into the Early Triassic.If the upper water became anoxic (Grice et al.,2005;Huang et al.,2007),even Hindeo-dus –-Isarcicella would be affected.Nicoll et al.(2002)also noted that Hindeodus was present in a wide range of marine depositional environments,but they thought the replacement of Neogondolella by Hindeodus –Isarcicella was due to an increase of turbidity levels.If the turbidity of the water was one of the main factors affecting the size reduction of Neogondolella as proposed by Luo et al.(2006),it cannot have been the reason for the size reduction of the conodont Hindeo-dus –Isarcicella .On the basis of previous literature regarding the ecology of Hin-deodus –Isarcicella and the characters of these conodonts at the Meishan A section,the authors consider that Hindeodus –Isarcicella were pelagic conodonts,maybe dwelling in the photic-zone or somewhat deeper,thereby appearing as fossils in both shallow and deep water facies.The anoxic event may have impacted on the evolution of Hindeodus –Isarcicella,which suggested that perhaps implying photic zone anoxia (such as bed 27at the Meishan Section,Grice et al.,2005).There are also different opinions regarding the feeding mechan-isms of conodonts.Nicoll (1985,1987)thought that the conodont apparatus is the ﬁltering array of a microphagous active suspension feeder,while others have interpreted it to be the grasping and food-processing structure of a macrophagous predator or scavenger (Briggs et al.,1983;Aldridge et al.,1987;Purnell,1993).In either case,the abrupt decline of food supplies could have driven the size reduction of the conodont populations,by creating high juvenile mortality.Based on the detailed study of the polygonal microsculpture of Neogondo-lella elements from bed 24e at Meishan (Jiang et al.,2008)indicates an high juvenile mortality at this bed.5.2.Palaeoenvironmental changes during the P/T transition5.2.1.Sea-level changesZhang et al.(1996)studied the sequence stratigraphy of the Meishan D section in detail and proposed that the top contact of bed 24d is a type II sequence boundary,that bed 24e was an upward shallowing parasequence,and that bed 27b to 29belongs to a transgressive systems i et al.(2001)and Lai and Zhang (1999)analyzed the sea-level change bed by bed from bed 24d to 29of the Meishan D section.They thought that the depth of deposition of bed 24d was about 20–60m,while that of bed 24e was about 30–40m.Bed 25,the “white clay bed ”,is composed of montmorillonite –illiteFig.6.Variation of the mean size of P1elements of Hindeodus from the earliest Triassic of the Shangsi Section,Sichuan Province.The black area is the 95%con ﬁdence interval of the mean size,and the central white circle and line show variation of the mean size.181G.Luo et al./Palaeogeography,Palaeoclimatology,Palaeoecology 264(2008)176–187。

Abstract

On Preservation under Homomorphisms and Unions of Conjunctive QueriesAlbert Atserias∗Universitat Polit`e cnica de Catalunya,Dept.LSIJordi Girona Salgado1-308034Barcelona,Spainatserias@lsi.upc.esAnuj Dawar†University of Cambridge Computer LaboratoryJ.J.Thomson AvenueCambridge CB30FD,U.K.anuj.dawar@Phokion G.Kolaitis‡IBM Almaden Research Center650Harry RoadSan Jose,CA95120,U.S.A kolaitis@March2,2006AbstractUnions of conjunctive queries,also known as select-project-join-union queries,are the most fre-quently asked queries in relational database systems.These queries are deﬁnable by existential positiveﬁrst-order formulas and are preserved under homomorphisms.A classical result of mathematical logicasserts that the existential positive formulas are the onlyﬁrst-order formulas(up to logical equivalence)that are preserved under homomorphisms on all structures,ﬁnite and inﬁnite.After resisting resolu-tion for a long time,it was eventually shown that,unlike other classical preservation theorems,thehomomorphism-preservation theorem holds for the class of allﬁnite structures.In this paper,we showthat the homomorphism-preservation theorem holds also for several restricted classes ofﬁnite structuresof interest in graph theory and database theory.Speciﬁcally,we show that this result holds for all classesofﬁnite structures of bounded degree,all classes ofﬁnite structures of bounded treewidth,and,moregenerally,all classes ofﬁnite structures whose cores exclude at least one minor.1IntroductionIt is well known that the most frequently asked queries in databases are expressible in the select-project-join-union(SPJU)fragment of relational algebra(see[1]).From the point of view of relational calculus orﬁrst-order logic,the class of SPJU queries corresponds to the class of queries deﬁnable by existential positive formulas ofﬁrst-order logic,that is,formulas built from atomic formulas using conjunction,dis-junction,and existential quantiﬁcation only.By distributing conjunctions and existential quantiﬁers over ∗Partially supported by CICYT TIC2001-1577-C03-02and the Future and Emerging Technologies programme of the EU under contract number IST-99-14186(ALCOM-FT).†Research supported in part by EPSRC grant GR/S06721.‡On leave from UC Santa Cruz.Research partially supported by NSF Grant No.IIS-99074191disjunctions,every existential positive formula can be written as a disjunction of existential formulas in which the quantiﬁer-free part is a conjunction of atomic formulas.It is for this reason that SPJU queries are also known as unions of conjunctive queries.Starting with the work of Chandra and Merlin[7],the study of conjunctive queries and their unions has occupied a central place in database theory;in particular, researchers have investigated in depth certain fundamental algorithmic problems about(unions of)conjunc-tive queries,such as the containment and the evaluation problem for these queries.Let A=(A,R A1,...,R A m)and B=(B,R B1,...,R B m)be two relational structures over the same vocabulary(database schema)R1,...,R m.Recall that a homomorphism from A to B is a map h:A→B such that for every relation symbol R i and every tuple a=(a1,...,a r)from A,if a∈R A i then h(a)= (h(a1),...,h(a r))∈R B i.As already realized by Chandra and Merlin[7],the study of conjunctive queries is intimately connected to homomorphisms.In particular,unions of conjunctive queries are preserved under homomorphisms,where a query q is said to be preserved under homomorphisms if whenever a∈q(A) and h is a homomorphism from A to B,then h(a)∈q(B).Note that if a query q is preserved under homomorphisms,then it is also preserved under extensions,which means that whenever A is an induced substructure of B and a∈q(A),then a∈q(B).In addition,such a query q is monotone,which means that whenever a∈q(A)and B is obtained from A by adding tuples to some of the relations of A,then a∈q(B).These preservation properties can be thought of as asserting that the query satisﬁes a strong form of the open world assumption,in that a tuple in the result of the query will remain so under the addition of new facts to the databases,such as the introduction of new elements and new tuples in the relations.Classical preservation theorems of model theory are results that match semantic properties ofﬁrst-order formulas with syntactic properties ofﬁrst-order formulas.Speciﬁcally,theŁo´s-Tarski Theorem asserts that aﬁrst-order formula is preserved under extensions on all structures(ﬁnite and inﬁnite)if and only if it is logically equivalent to an existential formula(see[26]).Another classical preservation theorem in model theory,known as Lyndon’s Positivity Theorem,states that aﬁrst-order formula is monotone on all structures (ﬁnite and inﬁnite)if and only if it is logically equivalent to a positiveﬁrst-order formula.The non-trivial part in these results is to show that if aﬁrst-order formula has the semantic property stated,then it is logically equivalent to aﬁrst-order formula that has the corresponding syntactic property.The proofs make an essential use of the Compactness Theorem ofﬁrst-order logic(and,hence,of inﬁnite structures).The same technique can also be used to show that the following homomorphism-preservation theorem holds:a ﬁrst-order formula is preserved under homomorphisms on all structures(ﬁnite and inﬁnite)if and only if it is logically equivalent to an existential positiveﬁrst-order formula.The aforementioned classical preservation theorems are about the class of all structures(ﬁnite and inﬁ-nite)over someﬁxed vocabulary.It is natural to ask whether these preservation theorems relativize,that is, whether they hold on restricted classes of structures.Note that if a preservation theorem holds for a class C of structures,then restricting the statement of the theorem to a subclass C of C weakens both the hypoth-esis and the conclusion of the theorem.Thus,unlike many other results of model theorem,a preservation theorem may hold for a class C of structures,but may fail for some subclass C of C.Research inﬁnite model theory addressed the question of whether classical preservation theorems about the class of all structures hold for the class of allﬁnite structures.As it turned out,classical preservation theorems tend to fail when we restrict ourselves toﬁnite structures.In particular,theŁo´s-Tarski Theo-rem fails in theﬁnite,that is,there is aﬁrst-order formula that is preserved under extensions on the class of allﬁnite structures,but is not equivalent to any existential formula[36,23].Similarly,Lyndon’s Pos-itivity Theorem is also known to fail in theﬁnite[2,35].As for the homomorphism-preservation theo-rem,its status in theﬁnite had remained unsettled for quite a long time.In fact,theﬁnite version of the homomorphism-preservation theorem had received considerable attention by theﬁnite model theory com-2munity and had been singled out as a central problem(Problem5.9on theﬁnite model theory website at rmatik.rwth-aachen.de/FMT/).Moreover,it motivated a lot of re-lated research in this area,including[4,16,24,32].Eventually,in an important breakthrough,Rossman [33]proved that the homomorphism-preservation theorem does hold in theﬁnite.In other words,Rossman proved that if aﬁrst-order formula is preserved under homomorphisms on the class of allﬁnite structures, then it is equivalent,onﬁnite structures,to an existential positiveﬁrst-order formula.In particular,suppose that some arbitrary relational algebra query which may also involve the set-theoretic difference operator is preserved under homomorphisms on allﬁnite structures;Rossman’s result shows that this query can be transformed to an equivalent SPJU query.In this paper,we show that the homomorphism-preservation theorem holds for numerous restricted classes ofﬁnite structures of interest in graph theory and database theory.It should be noted that our results were established and published in preliminary form[6]before Rossman proved that the homomorphism-preservation theorem holds for the class of allﬁnite structures.It should also be pointed out that our results are not implied by Rossman’s theorem,since,as explained earlier,preservation theorems about a class of structures need not relativize to a subclass of that class.In its full generality,our main result asserts that the homomorphism-preservation theorem holds for every class C ofﬁnite structures that is closed under substructures and disjoint unions,and has the property that the Gaifman graphs of the structures in C exclude at least one minor.This result contains as special cases the homomorphism-preservation theorem for the classes of all structures of bounded treewidth,and the classes of all structures that exclude at least one minor;in particular,the homomorphism-preservation theorem holds for the class of all planar graphs.If we restrict attention to Boolean queries,we are able to further extend the classes of structures on which the homomorphism preservation theorem holds.In particular,we can show that the theorem for Boolean queries holds on every class C ofﬁnite structures that is closed under substructures and disjoint unions,and such that the cores of the structures in C exclude at least one minor.To put these results in perspective,let us brieﬂy comment on some of the key notions.Treewidth is a measure of how tree-like a graph(or,more generally, a relational structure)is.It has played a key role in Robertson and Seymour’s celebrated work on graph minors(see[12]).Moreover,classes of structures of bounded treewidth have turned out to possess good algorithmic properties,in the sense that various NP-complete problems,including constraint satisfaction problems and database query evaluation problems,are solvable in polynomial-time when restricted to inputs of bounded treewidth[10,12,21,22].The core of a structure A is a substructure B of A such that there is a homomorphism from A to B,but there is no homomorphism from A to a proper substructure B of B.This concept originated in graph theory(see[25]),but has found applications in conjunctive query processing and optimization[7]and,more recently,in data exchange[15].The proofs of our results combine earlier work about preservation properties in theﬁnite with some heavy combinatorial machinery.Ajtai and Gurevich[3]showed that if a query q on the class of allﬁnite structures is expressible in both Datalog andﬁrst-order logic,then it is also deﬁnable by an existential positive formula;furthermore,every Datalog program deﬁning q must be bounded.This is an important result about Datalog programs in its own right,but it is also a partial result towards the homomorphism-preservation theorem in theﬁnite because all Datalog queries are preserved under homomorphisms(since such queries are inﬁnitary unions of conjunctive queries).At a high level,the proof of the Ajtai-Gurevich theorem can be decomposed into two modular parts.Theﬁrst is a combinatorial lemma to the effect that if q is aﬁrst-order query that is preserved under homomorphisms onﬁnite structures,then the minimal models of q satisfy a certain“density”condition(incidentally,the minimal models of a Boolean query that is preserved under homomorphisms are cores).The second part shows that if all minimal models of a Datalog query satisfy the“density”condition,then there are onlyﬁnitely many of them.This means that q3hasﬁnitely many minimal models,which easily implies that q is deﬁnable by a union of conjunctive queries. To obtain our main theorem,we use the same architecture in the proof,but,in place of the second part,we essentially show that if C is a class ofﬁnite structures satisfying the hypothesis of the theorem(such as having bounded treewidth or excluding a minor),then every collection of structures in C that satisﬁes the “density”condition must beﬁnite.In turn,this requires the use of the Sunﬂower Lemma of Erd¨o s and Rado, as well as Ramsey’s Theorem.Furthermore,equipped with this new machinery,we obtain a different and perhaps more transparent proof of the Ajtai-Gurevich Theorem.Actually,we show that the Ajtai-Gurevich Theorem can be extended to a family ofﬁnite-variable inﬁnitary logics that taken together are strictly more expressive than Datalog. This is obtained by using tight connections between number of variables,treewidth,and minimal models.In Section2,we review some basic notions from logic and graph theory that we will need in the se-quel.Section3contains certain combinatorial facts about the minimal models of aﬁrst-order query that is preserved under homomorphisms.In Sections4and5,we establish the main results regarding classes of bounded treewidth and classes with excluded minors respectively.In Section6we discuss the relation-ship between peservation for Boolean and non-Boolean queries.We show that the preservation results for Boolean queries can be established for larger classes of structures.Finally,in Section7we obtain the aforementioned extension of the Ajtai-Gurevich Theorem.2PreliminariesThis section contains the deﬁnitions of some basic notions and a minimum amount of background material.2.1Relational Structures and GraphsA relational vocabularyσis aﬁnite set of relation symbols,each with a speciﬁed arity.Aσ-structure A consists of a universe A,or domain,and an interpretation which associates to each relation symbol R∈σof some arity r,a relation R A⊆A r.A graph is a structure G=(V,E),where E is a binary relation that is symmetric and irreﬂexive.Thus,our graphs are undirected,loopless,and without parallel edges.Aσ-structure B is called a substructure of A if B⊆A and R B⊆R A for every R∈σ.It is called an induced substructure if R B=R A∩B r for every R∈σof arity r.Notice the analogy with the graph-theoretical concept of subgraph and induced subgraph.A substructure B of A is proper if A=B.A homomorphism from A toB is a mapping h:A→B from the universe of A to the universe ofB that preserves the relations,that is if(a1,...,a r)∈R A,then(h(a1),...,h(a r))∈R B.We say that two structures A and B are homomorphically equivalent if there is a homomorphism from A to B and a homomorphism from B to A.Note that,if A is a substructure of B,then the injection mapping is a homomorphism from A to BThe Gaifman graph of aσ-structure A,denoted by G(A),is the(undirected)graph whose set of nodes is the universe of A,and whose set of edges consists of all pairs(a,a )of distinct elements of A such that a and a appear together in some tuple of a relation in A.The degree of a structure is the degree of its Gaifman graph,that is,the maximum number of neighbours of nodes of the Gaifman graph.Let G=(V,E)be a graph.Moreover,let u∈V be a vertex and let d≥0be an integer.The d-neighborhood of u in G,denoted by N Gd(u),is deﬁned inductively as follows:1.N G0(u)={u};2.N Gd+1(u)=N Gd(u)∪{v∈V:(v,w)∈E for some w∈N Gd(u)}.4A tree is an acyclic connected graph.A tree-decomposition of G is a labeled tree T such that1.each node of T is labeled by a non-empty subset of V;2.for every edge{u,v}∈E,there is a node of T whose label contains{u,v};3.for every u∈V,the set X of nodes of T whose labels include u forms a connected subtree of T. The width of a tree-decomposition is the maximum cardinality of a label in T minus one.The treewidth of G is the smallest k for which G has a tree-decomposition of width k.The treewidth of aσ-structure is the treewidth of its Gaifman graph.Note that trees have treewidth one.For every positive integer k≥2,we write T(k)to denote the class of allσ-structures of treewidth less than k.In the sequel,whenever we say that a collection C ofσ-structures has bounded treewidth,we mean that there is a positive integer k such that C⊆T(k).We say that a graph G is a minor of H if G can be obtained from a subgraph of H by contracting edges. The contraction of an edge consists in identifying its two endpoints into a single node,and removing the resulting loop.An equivalent characterization(see[11])states that G is a minor of H if there is a map that associates to each vertex v of G a non-empty connected subgraph H v of H such that H u and H v are disjoint for u=v and if there is an edge between u and v in G then there is an edge in H between some node in H u and some node in H v.We will sometimes refer to the subgraphs H v as the connected patches that witness that G is a minor of H.It is not hard to see that T(k)is closed under taking minors,that is,if G is a minor of H and the treewidth of H is less than k,then the treewidth of G is also less than k.Since the treewidth of K k,the complete graph on k vertices,is k−1,it follows that K k+1is not a minor of any graph in T(k).Finally, we will make use of the fact that K k is a minor of K k−1,k−1,the complete bipartite graph on two sets of k−1nodes.To see this,contract the edges of a perfect matching of size k−2sitting inside K k−1,k−1.The result is a complete graph on k−2nodes,which,together with the remaining two nodes of K k−1,k−1and all remaining edges,gives a K k.2.2First-order Logic and Conjunctive QueriesLetσbe a relational vocabulary.The atomic formulas ofσare those of the form R(x1,...,x r),where R∈σis a relation symbol of arity r,and x1,...,x r areﬁrst-order variables that are not necessarily distinct. Formulas of the form x=y are also atomic formulas,and we refer to them as equalities.The collection ofﬁrst-order formulas is obtained by closing the atomic formulas under negation,conjunction,disjunction, universal and existentialﬁrst-order quantiﬁcation.The semantics ofﬁrst-order logic is standard.If A is aσ-structure andϕis aﬁrst-order formula,we use the notation A|=ϕto denote the fact thatϕis true in A.The collection of existential-positiveﬁrst-order formulas is obtained by closing the atomic formulas under conjunction,disjunction,and existential quantiﬁcation.By substituting variables,it is easy to see that equalities can be eliminated from existential-positive formulas.An important fragment of existential-positive formulas is formed by the collection of sentences of the form∃x1...∃x nθ,whereθis a conjunction of atomic formulas with variables among x1,...,x n.These formulas deﬁne the class of Boolean conjunctive queries(also known as select-project-join queries or,in short,SPJ-queries).In the sequel,we will occasionally use the term conjunctive query to denote both a formula∃x1...∃x nθas above and the query deﬁned by that formula.Everyﬁnite structure A with n elements gives rise to a canonical conjunctive queryϕA,which is obtained byﬁrst associating a different variable x i with every element a i of A,1≤i≤n,then forming the conjunction of all atomic facts true in A,andﬁnally existentially quantifying all variables x i,1≤i≤n.In other words,the formula5ϕA is the existential closure of the positive diagram of A(see[26]).Conversely,every conjunctive query ∃x1...∃x nθgives rise to a canonical structure A with n elements,where the elements of A are the variables x1,...,x n and the relations of A consist of the tuples of variables in the conjucts ofθ.Chandra and Merlin [7]showed the following basic result,which has found many uses in database theory and the theory of constraint satisfaction problems.Theorem1(Chandra-Merlin Theorem).Let A and B be twoﬁnite structures.The following statements are equivalent.1.There is a homomorphism from A to B.2.B|=ϕA.3.ϕB logically impliesϕA.2.3Inductive Deﬁnitions and DatalogLetσbe a relational vocabulary.An inductive system ofﬁrst-order formulas is aﬁnite sequenceϕ1(x1,...,x k1,S1,...,S r),...,ϕr(x1,...,x kr,S1,...,S r)ofﬁrst-order formulas such that each S i is a relation symbol of arity k i,not already inσ.Every such system gives rise to an operatorΦon sequences of relations of aσ-structure.More precisely,if A is aσ-structure with universe A and R i⊆A k i is a relation for every i∈{1,...,r},we deﬁneΦi(R1,...,R r)={(a1,...,a ki )∈A k i:A|=ϕi(a1,...,a ki,R1,...,R r)},andΦ(R1,...,R r)=(Φ1(R1,...,R r),...,Φr(R1,...,R r)).The stagesΦm=(Φm1,...,Φm r)ofΦaredeﬁned by the inductionΦ0i=(∅,...,∅),andΦm+1i =Φi(Φm1,...,Φm r).If each formulaϕi is positivein the relation symbols S1,...,S r,then the associated operatorΦis monotone in each of its arguments.In such a case,the sequence of stagesΦ0,Φ1,...converges to the leastﬁxed-pointΦ∞=(Φ∞1,...,Φ∞r)of the operatorΦ.Moreover,if A isﬁnite,then there exists aﬁnite m0such thatΦ∞=Φm0.A Datalog program is aﬁnite set of rules of the form T0←T1,...,T m,where each T i is an atomic formula.The left-hand side of each rule is called the head of the rule,while the right-hand side is called the body.The relation symbols that occur in the heads are the intensional database predicates(IDBs),while all others are the extensional database predicates(EDBs).Note that IDBs may occur in the bodies too,thus,a Datalog program is a recursive speciﬁcation of the IDBs with semantics obtained via leastﬁxed-points of monotone operators(see[37]).For example,the following Datalog program deﬁnes the transitive closure of the edge relation E of a graph G=(V,E):T(x,y)←E(x,y);T(x,y)←E(x,z),T(z,y).A key parameter in analyzing Datalog programs is the number of variables used.We write k-Datalog for the collection of all Datalog programs with at most k variables in total.For instance,the above is a3-Datalog program.A Datalog program can be read as an inductive system ofﬁrst-order formulas(as above)where each formula is existential positive.Let C be a class ofσ-structures.A query q on C of arity n is a map that associates to each structure A in C an n-ary relation q(A)on the domain of A that is preserved under isomorphisms between structures.Let6L be some logic.We say that q is L -deﬁnable on C if there exists a formula ϕof L such that if A is in C ,then a ∈q (A )if and only if A ,a |=ϕ.A Boolean query is a query of arity 0,which can be identiﬁed with an isomorphism-closed subclass of C .Equivalently,a Boolean query is a mapping q from C to {0,1}that is invariant under isomorphisms.We say that a Boolean query q is L -deﬁnable on C if there is a sentence ψof L such that for every A ∈C ,we have that q (A )=1if and only if A |=ψ.3Preservation under Homomorphisms and Minimal ModelsFor the purpose of the constructions in this paper,we shall restrict our attention speciﬁcally to Boolean queries.The reason for restricting ourselves to Boolean queries is that the notion of minimal model ,which we rely on,is more naturally deﬁned for Boolean queries.In Section 6we return to non-Boolean queries and explain why the results apply equally well to these.For a Boolean query q ,we say that a σ-structure A in C is a minimal model of q in C if q (A )=1and there is no proper substructure B of A in C such that q (B )=1.Recall from Section 2that substructures are not necessarily induced.The following characterization is part of the folklore,a proof for the class of all ﬁnite σ-structures can be found in [4].Here,we state it in a more general form for classes of ﬁnite σ-structures that are closed under substructures,and sketch a proof.Theorem 2.Let C be a class of ﬁnite σ-structures that is closed under substructures,and let q be a Boolean query on C that is preserved under homomorphisms on C .The following are equivalent:1.q has ﬁnitely many minimal models in C .2.q is deﬁnable on C by an existential-positive ﬁrst-order sentence.Proof (sketch).The direction (1)⇒(2)is established by constructing,for each ﬁnite structure A ,a canonical conjunctive query ϕA ,as described earlier.The required existential positive formula deﬁning q is now obtained as the disjunction of ϕA over all minimal models A of q .This follows from the preservation of q under homomorphisms and the fact that,by Theorem 1,a structure B satisﬁes ϕA if and only if there is a homomorphism from A to B .For the direction (2)⇒(1),we ﬁrst use the fact that every existential positive formula is equivalent to a ﬁnite disjunction m i =1ψi ,where each ψi is a conjunctive query.For each such conjunctive query ψi ,let A i be the canonical ﬁnite structure associated with ψi ,1≤i ≤m .Note that such a canonical structure A i need not be a member of C .Nonetheless,it is not hard to show that every minimal model B of q in C is equal to a homomorphic image h (A i )of one of the canonical ﬁnite structures A i ,1≤i ≤m .Thus,the cardinality of every minimal model of q in C is less than or equal to the maximum cardinality of the canonical ﬁnite structures Ai ,1≤i ≤m ,which implies that q has ﬁnitely many minimal models in C .By Theorem 2,to establish the homomorphism-preservation theorem for the class of all ﬁnite struc-tures,we would need to show that any ﬁrst-order deﬁnable query preserved under homomorphisms has only ﬁnitely many minimal models.Equivalently,it would sufﬁce to show that for any such query there is a bound on the size of the minimal models.Ajtai and Gurevich [3],in comparing the expressive power of Datalog and ﬁrst-order logic,showed that the minimal models of every ﬁrst-order sentence preserved under homomorphisms satisfy an interesting combinatorial property.Intuitively speaking,they are dense .More precisely,if there are arbitrarily large minimal models,then they cannot be very thinly spread out,which means that they do not contain a large set of elements all far away from each other.Furthermore,one cannot remove a small number of elements from a large minimal model to create such a scattered set.7The Ajtai-Gurevich proof of this property is based on Gaifman’s Locality Theorem forﬁrst-order logic [18].Before we state the precise result,we need a deﬁnition and a piece of notation.Let G=(V,E)bea graph.Recall the deﬁnition of d-neighborhood N Gd (u)in Section2.We say that a subset A⊆V of thenodes is d-scattered if N Gd (u)∩N Gd(v)=∅for every two distinct u,v∈A.For a graph G=(V,E)anda set B⊆V,we write G−B for the graph obtained from G by removing all nodes in B and the edges to which they are incident.This is a notation we will use repeatedly in the sequel.We are ready for the result of Ajtai and Gurevich.While they proved this for the class of allﬁnite structures,it is easy to see that the proof relativizes to classes satisfying some simple restrictions.This observation follows from the fact that disjoint union and taking a substructure are the only constructions used in the proof in[3].Theorem3.Let C be a class ofﬁniteσ-structures that is closed under substructures and disjoint unions. Let q be a Boolean query that isﬁrst-order deﬁnable and preserved under homomorphisms on C.For every s≥0,there exist integers d≥0and m≥0such that if A is a minimal model of q,then there is no B⊆A of size at most s such that G(A)−B has a d-scattered set of size m.In particular,there exist integers d≥0 and m≥0such that if A is a minimal model of q,then G(A)does not have a d-scattered set of size m.Now,let C be a class ofﬁniteσ-structures that is closed under substructures and disjoint unions.With Theorems2and3in hand,in order to establish that the homomorphism-preservation theorem holds on C, it sufﬁces to show that for some s and every d and m,all sufﬁciently large structures in C have d-scattered sets of size m after removing at most s elements.We formulate this observation as the following corollary, which we will use repeatedly in what follows.Corollary1.Let C be a class ofﬁniteσ-structures having the following properties:1.C is closed under substructures and disjoint unions;2.for some s and for all d and m,there is an N so that if A∈C has more than N elements,then thereis a set B of at most s elements such that G(A)−B has a d-scattered set of size m.On the class C,every Boolean query that isﬁrst-order deﬁnable and preserved under homomorphisms is deﬁnable by an existential positiveﬁrst-order formula.There is a case that is particularly easy in which we can take s=0.Lemma1.For every k≥0,d≥0,and m≥0,there exists an N≥0such that for all graphs G=(V,E G) with|V|>N and degree at most k,the graph G has a d-scattered set of size m.Proof.Fix d≥0and m≥0,let N=mk d,and let G=(V,E G)be a graph with|V|>N.The size of the d-neighborhood of every node in G is bounded by k d.Therefore,there are at least m nodes in G with disjoint d-neighborhoods.As an immediate corollary we obtain the homomorphism-preservation result for classes of structures of bounded-degree.Theorem4.Let C be a class ofﬁniteσ-structures that is closed under substructures and disjoint unions,and such that the structures in C have bounded degree.On the class C,every query that isﬁrst-order deﬁnable and is preserved under homomorphisms is also deﬁnable by an existential-positiveﬁrst-order formula.8。

R.R.P. van Nooyen

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Some preconditioners that show potential for parallelization are examined to judge their e ciency relative to the current ISNaS incompressible ow solver preconditioners. The experiments show that in 2D parallel versions of the current preconditioners outperform there rivals. In 3D the approximate inverse preconditioner shows promise as preconditioner for the pressure equation.
3 Numerical Experiments
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萨的名词解释英文版电子书

萨的名词解释英文版电子书Sah: An Exploratory Guide to an Enigmatic Electronic BookIntroductionIn this age of digital evolution, electronic books, or eBooks, have become an integral part of our reading habits. They have revolutionized the way we access and consume information. Among the plethora of eBooks available, one intriguing title emerges: "Sah: An Exploratory Guide to an Enigmatic Electronic Book." In this article, we delve into the enigmatic nature of Sah, exploring its unique characteristics, benefits, and impact on readers.Unveiling the Essence of Sah1. The Unprecedented Experience of SahSah presents an extraordinary reading experience that transcends traditional books. It seamlessly blends text, images, audio, videos, and interactive elements. By employing cutting-edge technology, Sah captivates readers by immersing them in an interactive narrative, enabling a dynamic exploration of the content.2. Pioneering Features of SahSah boasts innovative features that amplify the reading experience. The book's interface allows readers to annotate, highlight, and bookmark in real-time, providing a more personalized and interactive engagement. Furthermore, Sah's built-in search function enables users to navigate seamlessly through its extensive content, empowering effortless exploration of its wealth of knowledge.3. Extensive Knowledge BaseOne of Sah's distinguishing aspects is its comprehensive knowledge base. It covers a broad range of subjects, including literature, science, history, art, and more. Packed withrich information, Sah provides readers with a vast repository of knowledge, empowering them to broaden their intellectual horizons.Impact on Readers1. Enhanced Learning ExperienceSah's interactive nature fosters active learning, enhancing the absorption and retention of information. Through its multimedia features, Sah accommodates various learning preferences by appealing to visual, auditory, and kinesthetic learners. By immersing readers in a multi-sensory experience, Sah stimulates cognitive engagement, making the learning process enjoyable and effective.2. An Avenue for Creativity and ExpressionSah's unique format creates possibilities for creativity and expression. Through the integration of images, videos, and interactive elements, readers can embark on creative journeys where they visualize, interpret, and interact with the content in innovative ways. Sah empowers readers to become co-creators, intertwining their imagination with the author's vision.3. Accessible Knowledge for AllOne of the greatest strengths of Sah is its accessibility. With just a touch on a screen, Sah brings a wealth of knowledge to readers, irrespective of their geographical location or economic background. Sah eliminates the barriers to access, fostering inclusivity and enabling people from all walks of life to benefit from its transformative potential.The Future and Evolution of SahAs technology continues to evolve, Sah is poised to adapt and push the boundaries further. With the incorporation of emerging technologies such as virtual reality and artificial intelligence, Sah could evolve into an even more immersive and personalized reading experience. These advances suggest that Sah represents just the beginning of a revolutionary shift in the way we engage with books.ConclusionSah, the enigmatic electronic book, breaks away from traditional literary formats, offering readers an unparalleled experience. Its fusion of text, multimedia, and interactive elements provides an immersive and stimulating environment for learning and creativity. Furthermore, Sah's accessibility ensures that knowledge is no longer confined to a select few but becomes an enriching resource for all. As the world embraces the digital age, Sah stands as a testament to our evolving relationship with literature and technology, paving the way for a new era of reading.。

savoir 从句

savoir 从句
"知道"从句是一个法语语法概念，用来描述一个主句中的动作或状态是由另一个从句中的动词所引起或影响的情况。

在这种结构中，主句中的动词通常是"知道"（savoir）或"相信"（croire）等表示认知或信仰的动词。

"知道"从句通常由一个连接词引导，比如"que"或"qui"。

例如，在句子"Je sais que tu es occupé"（我知道你很忙），从句"que tu es occupé"（你很忙）是由主句中的"Je sais"（我知道）引起的。

"知道"从句可以包含各种时态和语态，取决于主句中的动词的时态和语态。

例如，主句和从句可以同时处于过去时，未来时，条件时或虚拟时等。

另外，"知道"从句也可以包含各种不同类型的从句，比如陈述句、疑问句、感叹句等。

总的来说，"知道"从句是法语中一个重要的语法结构，用来描述认知或信仰对主句中的动作或状态的影响。

它在表达复杂的思想和观点时起着重要作用，需要在学习法语语法时认真掌握和理解。

Invacare AVIVA FX Power Wheelchair with Captain's

Invacare is pleased to offer you an upgraded solution to your ordering process. Our enhanced order forms allow you to fill out a form electronically, print and fax the form, save and email* it to Customer Service, or maintain the business practices that work for you today. The format has been revised to reveal a cleaner look with electronic selection and input functions.Adobe Acrobat Reader DCInteractive functions of our new forms work best with the latest version ofAdobe Acrobat Reader DC visit https:///reader/ to download andinstall on your PC or Mac or visit Google Play/ iTunes to download the Adobe Acrobat Reader DC app for your device.*Thank you for using Invacare eForms.For additional information please visit /eFormsSubmitPrintSaveInvacare ® AVIVA™ FX Power Wheelchairwith Captain’s Seat & LiNX ElectronicsIf you do not have access to Adobe Acrobat Reader DC simply print this form and complete it by hand and fax it to our Customer Service Departmentat:800-678-4682Adobe Acrobat Reader DC allows you to save this form with your content - to complete later or use as a starting point for your next form. Please note that content must be added and saved in Acrobat - saving content from completed forms in the browsermay not be possible.Adobe Acrobat Reader DC allows you to submit this form electronically via your emailclient. Simply click the submit button below and step through thesimple process.SUBMITCLEAR FORM PRINT FORMDate:PO:Account #:Contact:RTS/Therapist:Tag:Phone:Fax:Email:SHIP TOClient Height:Comments:Request Type:Quote OrderBASE OPTIONS Base ModelsIFX-20CName:Address:Apt:City:State:Zip:AVIVA FX Base for Captain’s Seat K0849$7,995User Weight LimitsU300User Weight under 300 lbsStandardClient Weight:Knee to Heel:Battery Tray TypeGP24Group 24 Battery BoxNCLights & IndicatorsLIGHTSLED lights and indicators (1)(2)$7001. Must order REM216, REM400 or REM500Batteries24BATTERYGroup 24 Battery, Pair (On Chair) E2363$600Battery Charger Option110CHARGER 110 Volt Battery Charger NC L8900Omit Battery Charger-$80IFX-20RAVIVA FX Base for Rehab Seating K0848$7,995Caster OptionAB1228-38” x 2.5” Black Casters w/ Solid InlayNCPerformance MotorsHSMTRPerformance Motors – 7.5 mph (1)$1,4001. Must order 24TRYTransport OptionsTRBKTS Wheelchair Transport Brackets StandardTRROTransport Ready Option(1)$501. TRRO Meets ISO-7176 Part 19Tire OptionAB1431-314” x 3” Black Tires w/ Gel Foam InsertsNCShroud Color (Must pick one)Rim Insert Color (Must pick one)164PR Standard Black NC 165PR Anthracite Black NC 166PR Mercury Blue NC 167PR Bengal Red NC 168PR Silver Star NC 169PRMidnight PurpleNC164P Standard Black NC 165P Anthracite Black NC 166P Mercury Blue NC 167P Bengal Red NC 168P Silver Star NC 169PMidnight PurpleNCMidnight PurpleAnthracite BlackStandard BlackSilver StarMercury BlueBengal RedElevating SeatELEVSeat-To-Floor HeightLOW Low Seat-To-Floor 20.5”NC MED Medium Seat-To-Floor 21.5”NC TALLTall Seat-To-Floor 22.5”NCELOW Extra Low Seat-To-Floor 19.5”NC Elevate Lift 12” E2300$2,995Captain Seat Width SettingVW1616” Wide NC VW1818” Wide NC VW2020” Wide NC VW2222” WideNCCaptain Seat Width SettingVD1616” Deep NC VD1717” Deep NC VD1818” Deep NC VD1919” Deep NC VD2020” DeepNCSeat Width/Depth CompatabilityVD16VD17VD18VD19VD20VW16X X X VW18XXX VW20X X X VW22XXXAdjustable Rehab Seat Width RangeCaptain Seat Style1620W SEMIR 16”-20” Width Range Semi-Recline Captain’s Seat N/C Standard2022WSEMIRB20”-22” Width RangeSemi-Recline with Solid SeatN/C$100Rehab Seat Width SettingsW16D1616” Wide 16” Deep N/C N/C W17D1717” Wide 17” Deep N/C N/C W18D1818” Wide 18” Deep N/C N/C W19D19W20D20W21D21W22D22D2319” Wide 19” Deep 20” Wide 20” Deep 21” Wide K010821” Deep K010822” Wide K010822” Deep K010823” Deep K0108N/C N/C N/C N/C $329$529$329$529$529N/C N/CAdjustable Rehab Seat Depth RangeRehab Seat Depth Settings1620D 16”-20” Depth Range 2023D20”-23” Depth Range1.For Captain Seat OnlySeat Cushion OptionsLC Matrx-Libra 16”w - 20”w E2624$485LC Matrx-Libra 21”w E2624$525LC Matrx-Libra 22”w E2625$595CCOCOn Chair Cushion Credit-$90PS-V Matrx PS 16”w – 20” w E2605$345PS-V Matrx PS 22”w E2606$695CCOCOn Chair Cushion Credit-$90MA-VI Matrx Vi 16”w – 21” w E2607$425MA-VI Matrx Vi 22”w E2608$475CCOC-$90Invacare Matrx Libra CushionInvacare Matrx PS CushionInvacare Matrx-Vi CushionOn Chair Cushion CreditFinished Back Height - Rehab SeatRehab Back CanesRehab Back Cane Angle SettingRehab Seat Back OptionsSLNGK Sling BackN/C RHBK Standard Rehab Back and Cushion N/C RPIP Recessed Planar Interface Plate $125OMBOmit Standard Rehab Back and Cushion$8018”18”90º19”20”91º20”22”95º21”24”96º22”20”23”22”24”24”25”1. 4-5” Gap from bottom of back pan to seat pan2. Finished back height measured from seat pan to top of back restNCNCNCNCFinished Back Height (1)(2)Straight Back Cane Height Backrest Angle Angled Back Cane Height Upgradable Back OptionsHB16High Back 16” high $595HB18High Back 18” high $595HB20High Back 20” high $595BCOCOn Chair Matrx Back Credit-$125E2620PBE14Matrx Elite 14” high (1)$625PBE16Matrx Elite 16” high $625PBE18Matrx Elite 18” high $625PBE20Matrx Elite 20” high $625E2620BCOCOn Chair Matrx Back Credit-$125PBEH16Matrx Elite HD 16” high$795PBEH20Matrx Elite HD 20” high $795BCOCOn Chair Matrx Back Credit-$125E2620 22”w E2621(1)EDB14Matrx Elite Deep 14” high$760EDB16Matrx Elite Deep 16” high $760EDB18Matrx Elite Deep 18” high$760EDB20Matrx Elite Deep 20” high x 24” wide $760E2620BCOCOn Chair Matrx Back Credit-$125PBETR16Matrx Elite TR 16” high$650PBETR18Matrx Elite TR 18” high $650PBETR20Matrx Elite TR 20” high $650BCOCOn Chair Matrx Back Credit-$125E2620EDBHD16Matrx Elite Deep HD 16” high $795EDBHD18Matrx Elite Deep HD 18” high $795EDBHD20Matrx Elite Deep HD 20” high $795BCOCOn Chair Matrx Back Credit-$125E2620 22”w E2621(1)1. Only available in 21” or 22” width1. Not compatable with 19” or 20” wide seatsMPB-V16Matrx PB (Posture Back) 16” high $625MPB-V20Matrx PB (Posture Back) 20” high$625E2620MPB-D16Matrx Posture Back Deep 16” high$645MPB-D20Matrx Posture Back Deep 20” high $645BCOCOn Chair Matrx Back Credit-$125E2615Standard Front RiggingLap Belts1515Seat Positioning Strap (1)NC 1. Please select with TRBKTS option 2. For Rehab Seat OnlyCaptain Seat Arm TypeLVAHF Left full length, adjustable height E0973$115LVAHD Left desk length, adjustable height E0973$115RVAHF Right full length, adjustable height E0973$115RVAHDRight desk length, adjustable height E0973$115PBSSB-48Push Button Style Lap Belt, Length 48” (2)StandardPBSSB-60Push Button Style Lap Belt, Length 60” (2)NC PBSSB-70Push Button Style Lap Belt, Length 71” (2)NC PLB2Bodypoint ® Padded Lap Belt 2 Point(67” length)(2)$170PLB4Bodypoint ® Padded Lap Belt 4 Point (67” length)(2)$215FCMT70Basic Fixed Center Mount Platform 70°(1)(2)NC FCMT90Basic Fixed Center Mount Platform 90º(1)(2)NC FCMT97Basic Fixed Center Mount Platform 97º(1)(2)NC FCPFlat Calf Pads for Fixed Center Mount Foot Platform (3)$3501. Comes standard with 12”x11” footplate (no heel loops)2. Seat pan to footplate 9”-17”3. Rehab Seat OnlyMEHSP-6Matrx Elan Standard Pad 6” E0955$235MEHSP-10Matrx Elan Standard Pad 10” E0955$235MEHSP-14Matrx Elan Standard Pad 14” E0955$235MEHOP-9Matrx Elan Occipital Pad 9” E0955$235MEHOP-12Matrx Elan Occipital Pad 12” E0955$235MEH-4P Matrx Elan 4-Point Pad 11”W x 10”H $325CAHConcepts Auto Style Headrest E0955$3501. If mounting on PB Elite must order removable hardwareMatrx Headrest Pads with Standard Cover (1)MEMAH Elan Multi-Axis Removable HDW E1028$220CMAHMotion ConceptsMulti-Axis Removable HDW E1028$195Headrest Mounting HardwareULMFB ADPAH-S ADPAH-M ADPAH-T Horizontal Arm Tube Extension Left NC HTE-L Ultra Rail Seat Mnt Flip Back Cantilever MAXX Tilt Arm (9-12.5”)Adult Dual Post Adj. Height 9.75”-12.75” w/ flat pouchAdult Dual Post Adj. Height 12.75”-15.75” w/ flat pouch Adult Dual Post Adj. Height 15.75”-18.75” w/ flat pouch $250StandardStandard Standard Rehab Arm Rests (1)Horizontal Arm Tube Extension RightNCHTE-R1. Height measured from seat pan to top of tubeRehab Arm Pads (1)ERGOLErgonomic Arm Trough – Left E2209$85ERGOR Ergonomic Arm Trough – Right E2209$85FHL-LT Flat Hand Pad – Left(2)$55FHP-RTFlat Hand Pad – Right (2)$55WFALL-LF Left Full (14”)$20WFALL-LDLeft Desk (10”)$20WFALL-RF Right Full (14”)$20WFALL-RDRight Desk (10”)$20Modular Integral Soft Skin FoamMISK-LF Left Full (14”)$32MISK-LDLeft Desk (10”)$32MISK-RF Right Full (14”)$32MISK-RDRight Desk (10”)$321. Full length pads ship with full length arm tubes (w/ extension); ergo trough ships with desk length tubes (w/o extension)2. Must order ergo troughMSTEX-LF Left Full (14”)$32MSTEX-LD Left Desk (10”)$32MSTEX-RF Right Full (14”)$32MSTEX-RDRight Desk (10”)$32Rehab Arm Pads (continued)(1)STAP-LFLeft Full (2.25” x 14”)Standard STAP-LD Left Desk (2.25” x 10”)Standard STAP-RF Right Full (2.25” x 14”)Standard STAP-RD Right Desk (2.25” x 10”)StandardOAP Omit Arm Pads-$25Footrest/Legrest Accessories1337Calf Strap E0038$27IMPACT6Impact Guards $511346Heel Loop (pair) E0951$45LPT2Longer Pivot Slide Tube for 1350$83ALPT Longer Pivot and Slide Tube $84ALPT4Longer Pivot Slide Tube 4”$84CTMT-FJ IVC Center Foot Platform adjustable knee angle (9.25” – 12” STF) E0990(1)(2)$270CTMT-FIVC Center Foot Platform adjustable knee angle (12.25” – 15” STF) E0990(1)(2)$2701. Not available with 16” seat depth2. STF height raised 1.5” with elevateFootplate Options for Manual Center MountSML Small Foot Plates (5.25” x 8”)NC MDM Medium Foot Plates (5.25” x 10”)NC LRG Large Foot Plates (5.9” x 12”)NC CTMTFBCenter Mount Foot BoardNCManual Center MountFootplates1651Composite Flip-up FootplatesNC AT5543Adjustable angle Flip-up Footplates K0040$1651350Extra Large Aluminum Footplates$1001. Rehab Seat OnlyMELR MAXX Swing-AwayManual Elevating - Straight E0990$680MAXX Style Elevating Side Mounted - Manual (1)MSKTHL-S Length: 10”-14”NC MSKTHL-M Length: 13”-17”NC MSKTHL-LLength: 16”-20”NCELECTRONICSREM110SS LiNX REM110 Joystick with Egg Switch for single actuatorNCNon-ExpandableREM210SSLiNX REM210 Joystick allows through the drive control operation of single actuator (requires STTDC)NC REM110LiNX Drive Only Remote (One Drive Function)NC Non-Expandable Single Drive Joystick (1)EXPCExpandable Controller E2377$700ExpandablePWH Harness Req. for Exp. System E2313$450REM211LED Expandable Remote (1)(3)StandardREM216LED Expandable Remote with Lights (2)(3)$350REM400Color 3.5” Touch Screen Remote (3)$1,0001. Not available with lights & indicators 2. Must pick lights & indicators3. Must choose expandable and PWH4. Rehab seat onlySTTDC Function key for operation of single actuator through the drive control E2310$1,795NEXCNon-Expandable ConrollerNCSW400TGL Toggle Kit for REM400$200REM500LiNX Color 3.5” Touch Screen (3)(4)Display Only (No Driver Control)$1,5001. Rehab Seat Only2. Only One INPUT Module per Chair (does not include IN200)OUT500INPUT IN200Output Module (1)LiNX Input Module (9 Pin Connection)(1)LiNX Input Module for Remote Power Switch (1)$500$1500$500Electronic Modules1. Right handed joystick is standardLEFT Left Handed Joystick Mount (1)NC Mounting for Driver ControlsQUAD Quad Link swing-away, height adjustable E1028$235RIGHT-Q Right Handed Joystick Mount NC LEFT-QLeft Handed Joystick MountNCManual Swing Away70NHD 70º Swing Away FootrestsNC M70HD70º HD Swing Away (Length 13”-17”)(1)(2)$4951. Must choose footplate2.Rehab Seat OnlyASL300A Egg Switch (1)$156Switch for Powered SeatingRIGHT-ASLMT Right Handed Mount NC LEFT-ASLMTLeft Handed MountNC1. STTDC or ASL300A required for ELEVLAK LiNX Access Key (1)$100LiNX Electronic AccessoriesPC101A Bodypoint ® U Shaped Handle 3”(1) E2323$120Joystick TopsPC102A Bodypoint ® U Shaped Handle 4”(1) E2323$120PC107A Bodypoint ® Rubber Dome (1) E2323$120PC110ABodypoint ® Grooved Mushroom Knob (1)E2323$1201560T Handle Flexible Joystick Ext.(1) E2323$1201561Straight Handle Flexible Joystick Ext.(1) E2323$1201. Only Available on REM400 Remote2. Captain Seat OnlyAccessoriesCSWH Walker Holder (2) K0108$100CSCC Cane and Crutch Holder (2) E2207$100CS0202 Holder (2) E2208$150USBCL USB Charger (Mounted in Left Rail (2)NC USBCRUSB Charger (Mounted in Right Rail)(2)NC1. Required for programming2.Rehab seat only。

洛菲YMSpectra+_Xcl操作说明

Imperfections 疵纱统计显示
经常性发生的缺点纱在纺纱工业里通称为疵纱。一般都认为疵纱长度愈短或是疵纱直径较小的变异，其发生频率比较高。这些疵纱发生的来源大都来自原料或是不恰当的制程。原料、梳棉针布、上下罗拉偏心弯曲、下皮辊损坏、钢丝圈以及钢领等等，对疵纱的产生都有重大的影响。对疵纱给予可信度高的分析，不但可以找寻一最佳的生产条件，更可以对纤维原料的相关品质条件下结论。
棉结
短粗/短粗节
图 4
长粗节纱及双股纱
细节纱
Yarn Clearing 细纱清纱
Base curve 基础曲线
要定义那些疵点纱必须切除或保留，首先必须考虑到络筒车的效率。此点前已提过，我们可以在平面坐标上以一曲线界定要切除的疵点纱（曲线上方)以及不要切除的疵点纱（曲线下方)，这曲线可称为理想理论曲线（RG) 图5的凹形曲线是很能符合实际需求。这凹形曲线是取源于纺织界的评估，直径大但长度短的疵点纱是可以接受的。不将这些小疵点切除，能符合提高筒子效率的要求。我们必须根据清纱器型式及灵活的条件设定，将理想曲线，以及实际能达成的曲线范围区分出来。
公司所提供。
• 电子清纱器未经授权自行变更以及修改。 • 正常损耗。
spectra+

概論
Ya纱疵点
定义
精纺工程是要纺出相当均匀的细纱，然而却无法避免直径不均匀细纱的出现。因此首先要区别细纱的不规则性是正常或是真正的疵点。细纱疵点也可以定义为细纱的不规则性。它可以造成后道工程的困难或成品的瑕疵。在筒子工程中清纱器可以检出并去除疵点，因此清纱器可说是络筒车的一部份。粗节纱去除疵点纱会妨碍筒子工程。筒子必须停车，切除疵点纱，而且还必须打结。很明显的，以上动作将造成筒子产量的损失。因此在品质与产量间需做个折衷，也就是要寻求出最大疵点切除数及最低生产损失的交集点。这折衷区分出以下不同：细节纱

salvo英语阅读

salvo英语阅读英文回答：Salvo is a term that is often used in military contexts to refer to a simultaneous discharge of artillery or firearms. It can also be used more broadly to describe a sudden and intense attack or barrage of something. For example, during a battle, soldiers may unleash a salvo of bullets at the enemy, or a country may launch a salvo of missiles at a target.In a more figurative sense, salvo can also be used to describe a verbal attack or criticism. For instance, if someone is being criticized harshly by a group of people, it could be said that they are facing a salvo of negative comments.Overall, the term salvo conveys a sense of sudden and intense action, whether it be in a military context or in a more metaphorical sense.中文回答：Salvo是一个在军事背景下经常使用的术语，用来指代炮火或枪炮的同时发射。

它也可以更广泛地用来描述突然而强烈的攻击或弹幕。

例如，在一场战斗中，士兵们可能向敌人发射一连串的子弹，或者一个国家可能向一个目标发射一连串的导弹。

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绿洲江南园
淡水湾花园旺角广场锦昌文华天寓纳爱斯湖光山色别墅上海114地块上海嘉和美舍上海东湖花苑别墅
上海
上海上海杭州杭州丽水无锡上海上海上海
平开内倒/外平开
内倒平开窗外平开平开内倒平开门推拉窗/幕墙窗平开内倒/外平开平开门外平开窗外平开窗
上海置业集团
上海天益集团上海黄浦地产发展集团浙江城建房地产开发集团六合房地产开发集团浙江纳爱斯集团无锡民生房地产集团上海瑞安集团上海家和房地产集团上海诚功集团
SAVIO 公司保证所售产品均为原装正品
三维独立可调重型门合叶MECHANICA
MECHANICA：三维独立可调重型门合页 •快速调节
MECHANICA重型门合页拥有创新的理念、5大独家专利，您可凭直观轻松调节，无需再将时间浪费于复杂的操作和计算上。
•简单、精确的安装
MECHANICA重型门合页具备三维（间距、压紧力、高度）独立可调（单位：毫米），两把内六角扳手就可轻易调节。
意大利SAVIO产品设计：
• • 唯一一家执手是请专业的、世界顶级的设计商设计的产品。 SAVIO执手与法拉利、蓝宝基尼、玛莎拉蒂等超级跑车共同出自欧洲顶级的工业设计商PINIFARINA。执手外观简洁流畅，符合当今流行趋势，执手上有人性化的凹槽设计，握持更舒适。 SAVIO产品是门窗五金行业的法拉利，使用在高端公寓、别墅可增加卖点，不仅具有顶级的品质，而且为业主带来浓郁的意大利艺术风情，为生活增添光彩。 PINIFARINA是这个世纪的超级设计商，经典跑车法拉利和蓝宝基尼的多款超级跑车之造型都由宾尼法尼纳操刀。在全球范围内的各大品牌汽车公司生产的汽车中，包括房车和小型轿车，十之八九的设计都和宾尼法尼纳有关。
上海陆家嘴联合房地产公司
青岛广业房地产开发集团青岛伟达软件开发集团重庆会展集团深圳新浩城房地产广州侨鑫集团丹麦格兰富上海古北集团(有限公司)
…
SAVIO项目实例
阿联酋，沙迦
在一百多年的历史当中，萨威奥公司参与合作了全球各地的诸多著名建筑，其优异的品质和完善的服务获得了世界范围的高度评价。
•适用于不同型材类型
该款合页应用范围广泛，可使用于任何规格的窗型材
SAVIO 项目实例
SAVIO中国地区工程案例表 (部分)
项目名称
北京东方瑞景北京ABP总部基地万达广场
所在地区
北京北京宁波
窗型
内倒平开窗上悬窗平开内倒/外平开
开发商
北京峻成房地产集团
北京道丰科技商务园开发集团大连万达集团
萨威奥五金贸易（上海）有限责任公司
意大利萨威奥铝合金门窗幕墙用五金系统
目
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录
SAVIO 公司介绍欧洲认证国内检测 SAVIO 产品系列 SAVIO 产品设计 SAVIO 产品特性 SAVIO 工程案例及图片
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SAVIO 公司简介
公司历史
பைடு நூலகம்
意大利萨威奥(SAVIO)有限公司始创于1889年，距今已有117 多年的历史，位于意大利北部都灵(Turin)市附近，专业从事铝门窗五金产品的生产。
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产品特点
传动件表面的黑色镀锌处理，大大增强了部件的防腐性能，延长了五金件的使用寿命。使之在各种各样的使用环境中，依然有良好表现。
欧标非隔热铝合金型材简介
萨维奥产品系列
Y轴
技术说明：五金槽口只要符合标准C槽即可，现在绝大多数型材厂家都有成熟的产品可以提供。
3
1.8 1.8 2.5
20
15
•通过欧洲专业RAL测试承重和持久度
MECHANICA重型门合页是唯一一款通过德国RAL EB2/150和EB3/150测试：承重达150公斤，并打破持久度记录，开启次数达到1,000,000次。
•无法比拟的高效品质和价格
欧洲RAL证书连同技术和应用的高效性价比使 MECHANICA重型门合页成为合页中的最佳，同时它结构独特、价格优越、适用场合广泛。
11.5 1.8 3 3.5 5 2.5
X轴
标准C槽尺寸图
1.5
4.5 10 22 7.5
SAVIO 产品系列
萨威奥铝合金门窗五金系统简介
按开启方式分类：
1.平开内倒窗 1.1 先平开后内倒 RIBANTA 4 1.2 先内倒后平开 RIBANTA 4 2.内平开窗 3.外平开窗
4.推拉门窗
5.平开门 6.中悬窗 7.幕墙开启扇
Rib.4 Log.先内倒后平开装置
配置表： 1.执手－873.3 9010/颜色可选
2.基本组合－3001
3.合叶组合－3000.731 9010 /颜色可选
Rib.4 Trad.先平开后内倒装置
配置表： 1.执手－873.3 9010/颜色可选 2.基本组合－3004 3.合叶组合－3000.731 9010 /颜色可选
在117年的历史中，萨威奥集团依靠不断创新的生产、卓越的品质和优良的价格，占据了本行业的领导地位。
公司规模
至今，萨威奥有限公司拥有多家下属公司，这些公司在该行业都具有非常重要的经验和专业知识
公司优势
凭借自身产品的卓越品质，萨威奥有限公司的产品已位于全球61 多个国家市场的前列，并占据了欧洲五金界的领导地位，在现有的市场保持270％的增长率
深圳金中环广场
SAVIO项目实例
Los Faros大厦，阿根廷，布依诺斯艾利斯，南美洲最高建筑
SAVIO项目实例
ABDUL AZIZ AL MAJID TWIN TOWER ，阿联酋，沙迦
SAVIO项目实例
Petrovskyfort, 圣彼得堡，俄罗斯
SAVIO项目实例
感谢您的支持
平开门五金
SAVIO 产品特性
意大利SAVIO门窗幕墙五金系统产品特点：
在全球所有的门窗五金系统中，世界公认的技术领航者按以下分类：德国的木（PVC）窗，意大利的铝窗。而SAVIO公司就来自于——意大利都灵。门窗五金系统最早来源于欧洲，欧洲的门窗五金检测标准也是全球最严格，最严谨的。SAVIO公司是五金行业中第一家获得 ISO认证的公司，所有产品均通过欧洲标准的严格检测，其中许多技术指标远远高于欧洲标准。意大利SAVIO公司是欧洲顶级的铝合金门窗五金配件供应商，具体表现在以下一些特征上，同时也是铝合金门窗五金配件行业中的唯一： 1 SAVIO执手是请专业的、世界顶级的设计商设计的产品。
中悬窗装置
中悬窗特点：
•外观框扇平齐，简洁大方。 •采用中间转换框的原理，达到开启扇以中轴为转轴可旋转180度，室外玻璃可以完全翻转到室内，极大的方便了清洗玻璃。安全，一部分在室外，一部分在室内，重心在轴上。 •不仅正面通风好，而且不阻碍侧面风，最大限度的通风。而普通的侧开窗会挡住一侧的风，通风量较小。 •中悬窗在一般的中小雨天气下也可开窗通风，因为自身的开启扇可形成一挡雨面。 •可以做在比普通50窗高的位置上，可以通过拉杆等辅助设施直接下拉或上推，即可开启或关闭窗扇。普通平开窗或上悬窗开启或关闭时，人手要伸到窗外一定距离，对于位置较高的窗很难操作。
上海陆家嘴中央公寓上海金桥S8 青岛玺景园青岛软件城重庆新会展中心深圳金中环广场广州汇景新城格兰富泵业苏州西山别墅
上海上海青岛青岛重庆深圳广州苏州苏州
断热推拉窗，推拉门断热推拉窗，推拉门内倒平开窗外悬窗幕墙中悬窗幕墙上悬窗外平开窗，推拉门平开内倒窗,平开门平开内倒窗
SAVIO项目实例 LG大厦
SAVIO项目实例
北京总部基地 ABP
SAVIO项目实例
北京总部基地 ABP
SAVIO项目实例
北京总部基地 ABP
SAVIO项目实例
青岛玺景园
SAVIO项目实例
上海绿洲江南园
SAVIO项目实例
杭州锦昌文华苑
SAVIO项目实例
广州汇景新城
SAVIO项目实例
DIN ISO14001认证
各种认证
SAVIO 产品设计
美的追求
设计系出名门极具美感追求时尚
即便是一个小小的五金件，也同样有其美学要求。SAVIO与世界顶级设计商Pininfarina合作，共同打造出集质与美于一身的五金产品。 Pininfarina 是这个世纪的超级设计商。法拉利、蓝宝基尼等超级跑车的经典造型设计都来自pininfarina的创意。与这些跑车一样SAVIO的产品也出自pininfarina的独创设计，其理念是简洁、现代、充满速度感和张力。
三维独立可调重型门合叶SUMMA
SUMMA：SAVIO最新款重型门合页 •简单、快速的安装
带预先安装的不锈钢背板，独特的翼边形状和不锈钢背板的外形设计可以使合页快速夹紧型材，因此甚至可以将合页装配在已经安装好的门上。合页表面的特别上倾面增加了背板的螺纹接触面，更加强了紧固性能。
•简单且独立调节
8.内倒侧滑门
9.高窗开启器
萨维奥产品系列
先平开再内倒窗，先内倒再平开窗萨威奥公司的RIBANTA 4承重可达100公斤，在上悬平开窗系列两翼合页领域内，即使到今天此承重量仍是最高水平。
萨威奥公司的RIBANTA 150承重可达150公斤。在同行中没有其他生产厂家可以生产承重达到 150公斤的内倒平开窗配件。
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10 11 12 13
执手背板及齿轮和拨叉均为镀锌钢，增强耐用性，齿轮采用快装方式而不是螺丝固定从而增强使用寿命。
锁点、锁块之间的锁闭为面接触，接触面积更大，结合更紧密，从而增强窗户的气密水密性能，减缓窗扇的变形率. 平开内倒窗/内倒平开窗的下轴承为“L”形设计，这样的设计能最大程度的增强整窗的承重性，保护窗框不变形。下轴承与下转轴设有防盗、防脱落装置，避免在内倒时强行撬开窗扇进入室内。专业性最强，历史最悠久，116年从事铝合金门窗及幕墙的五金配件生产与研发。