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211274788_单钢管避雷针高柔结构横风向风致响应研究★

第54卷第3期2023年5月太原理工大学学报J O U R N A L O F T A I Y U A N U N I V E R S I T Y O F T E C HN O L O G YV o l .54N o .3M a y 2023 引文格式:焦晋峰,苏亚兰,邓婕,等.单钢管避雷针高柔结构横风向风致响应研究[J ].太原理工大学学报,2023,54(3):473-481.J I A O J i n f e n g ,S U Y a l a n ,D E N G J i e ,e t a l .S t u d y o n c r o s s -w i n d r e s p o n s e o f s i n g l e s t e e l p i p e l i g h t n i n g r o d h i gh f l e x i b l e s t r u c t u r e [J ].J o u r n a l o f T a i y u a n U n i v e r s i t y o f T e c h n o l o g y,2023,54(3):473-481.收稿日期:2022-11-25;修回日期:2023-01-07基金项目:国家自然科学基金资助项目(52278198);山西省自然科技研究基金资助项目(202203021211184),山西省基础研究计划资助项目(202103021223105) 第一作者:焦晋峰(1979-),博士,副教授,主要从事钢结构与空间结构的研究,(E -m a i l )j i a o jf _1@126.c o m 通信作者:陈鹏程(1989-),博士,讲师,主要从事钢结构与空间结构的研究,(E -m a i l )c h e n p e ng ch e n g @t yu t .e d u .c n 单钢管避雷针高柔结构横风向风致响应研究焦晋峰1,2,苏亚兰2,邓婕2,付兴强2,陈鹏程2(1.吕梁学院建筑系,山西吕梁033000;2.太原理工大学土木工程学院,太原030024)摘要:单钢管避雷针结构横截面为圆形且基频较低,在运营过程中容易发生风振现象,采用双向流固耦合方法对其进行3维数值风洞模拟,探讨7种风速下钢管避雷针结构受力性能及风振响应,并与现行的国家规范条文对比㊂分析结果表明:在典型风速下避雷针结构两侧所受横风向风压力最大为1.03k P a ,是顺风向风压力的1.72倍,且在不同节段钢管连接处风压力突变现象显著;当风速大于10m /s 时,避雷针结构所受横风向风压大于规范提供的风荷载标准值,两者相差42%,且结构顶端位移相差30.6%;当风速大于20m /s 时,避雷针结构横风向振动频率与避雷针结构高阶自振频率接近,避雷针结构易发生高阶弯曲振动,存在安全隐患㊂关键词:双向流固耦合;单钢管避雷针结构;三维数值风洞模拟;横风向风压;风振响应中图分类号:T U 347 文献标识码:AD O I :10.16355/j .c n k i .i s s n 1007-9432t yu t .2023.03.010 文章编号:1007-9432(2023)03-0473-09S t u d y o n C r o s s -w i n d R e s p o n s e o f S i n g l e S t e e l P i p e L i g h t n i n gR o d H i gh F l e x i b l e S t r u c t u r e J I A O J i n f e n g 1,2,S U Y a l a n 2,D E N G J i e 2,F U X i n g q i a n g 2,C H E N P e n g c h e n g2(1.D e p a r t m e n t o f A r c h i t e c t u r e ,L y u l i a n g U n i v e r s i t y ,L y u l i a n g 033000,C h i n a ;2.C o l l e g e o f Ci v i l E n g i n e e r i n g ,T a i y u a n U n i v e r s i t y o f T e c h n o l o g y ,T a i yu a n 030024,C h i n a )A b s t r a c t :F o r s i n g l e s t e e l p i p e l i g h t n i n gr o d s t r u c t u r e t h a t h a s a c i r c u l a r c r o s s s e c t i o n a n d l o w f u n d a m e n t a l f r e q u e n c y ,w i n d v i b r a t i o n p h e n o m e n o n i s e a s y t o o c c u r i n t h e o pe r a t i o n p r o c e s s .T h e t w o -w a yf l u i d -s t r u c t u r e c o u p l i ng me t h o d w a s u s e d t o c o n d u c t t h r e e -d i m e n s i o n a l n u m e r i c a l w i n d t u n n e l s i m u l a t i o n ,a n d t h e m e c h a n i c a l p r o p e r t i e s a n d w i n d v i b r a t i o n r e s p o n s e of s t e e l p i pe l i g h t n i n g r o d s t r u c t u r e u n d e r s e v e n w i n d s pe e d s w e r e d i s c u s s e d .T h e o u t c o m e s w e r e a n d c o m -p a r e d w i t h c u r r e n t n a t i o n a l s t a n d a r d p r o v i s i o n s .T h e a n a l ys i s r e s u l t s s h o w t h a t t h e m a x i m u m t r a n s v e r s e w i n d p r e s s u r e o n b o t h s i d e s o f t h e l i g h t n i n g r o d s t r u c t u r e i s 1.03k P a u n d e r t y pi c a l w i n d s p e e d ,w h i c h i s 1.72t i m e s t h e d o w n w i n d w i n d p r e s s u r e ,a n d t h e a b r u p t c h a n ge of w i n d p r e s s u r e i s s ig n i f i c a n t a t th e c o n n e c ti o n o f s t e e l p i p e i n d i f f e r e n t s e c t i o n s .W h e n t h e w i n d s pe e d i s g r e a t e r t h a n 10m /s ,t h e t r a n s v e r s e w i n d p r e s s u r e of t h e l igh t ni n g ro d s t r u c t u r e i s g r e a t e r t h a n t h e s t a n d a r d w i n d l o a d v a l u e p r o v i d e d b y t h e s pe c if i c a t i o n ,t h e d i f f e r e n c e b e t w e e n t h e t w o i s42%,a n d t h e d i s p l a c e m e n t o f t h e t o p o f t h e s t r u c t u r e i s30.6%.W h e n t h e w i n d s p e e d i s g r e a t e r t h a n20m/s,t h e t r a n s v e r s e v i b r a t i o n f r e q u e n c y o f t h e l i g h t n i n g r o d s t r u c t u r e i s c l o s e t o t h e h i g h-o r d e r n a t u r a l v i b r a t i o n f r e q u e n c y o f t h e l i g h t n i n g r o d s t r u c t u r e,a n d t h e l i g h t n i n g r o d s t r u c t u r e i s p r o n e t o p r o d u c e h i g h-o r d e r b e n d i n g v i b r a t i o n,w h i c h h a s s a f e t y r i s k s.K e y w o r d s:b i d i r e c t i o n a l f l u i d-s t r u c t u r e c o u p l i n g;s i n g l e s t e e l p i p e l i g h t n i n g r o d c o n s t r u c t i o n;3D n u m e r i c a l w i n d t u n n e l s i m u l a t i o n;c r o s s w i n d p r e s s u r e;w i n d-i n d u c e d r e s p o n s e为避免雷击作用对变电站造成严重损害,通常采用避雷针结构作为主要防雷措施,其按构造主要分为构架避雷针结构㊁单钢管避雷针结构和格构式避雷针结构等,其中高度为35m的单钢管避雷针结构具有构造简单㊁轻质高强㊁占地较少等优点而被广泛使用㊂此类避雷针为圆截面结构,长细比较大,具有高柔性,且结构基频较低,故在运营过程中受到风荷载影响较大㊂风场流动时会在结构尾迹形成强烈的漩涡,漩涡交替脱落,使绕流物体上产生横风向交变侧向力,当漩涡脱落频率与避雷针结构的固有频率接近时会产生涡激共振,从而对避雷针结构造成严重损伤㊂例如,甘肃地区和新疆地区部分变电站避雷针结构发生倾倒事故造成变电站相关设施发生故障,通过对避雷针结构设计㊁安装及风振特性等方面的综合分析,得出事故的原因为处于风场迎风侧最上游的钢管避雷针,在湍流强度较低的流场中和适宜的风速条件下发生了涡激共振[1-2],因此,针对风荷载作用下避雷针结构的涡激振动问题亟需深入研究㊂目前针对风绕流引起圆柱体结构涡激振动的问题已有大量研究,大部分研究者采用F L U E N T㊁C F X㊁M i d a s N F X等软件研究了不同雷诺数条件下,圆柱绕流的流场特性[3-5]㊂陶涛等[6]基于涡激振动相关标准对风电机组高柔塔进行二阶涡激振动特性分析,揭示了高柔塔二阶涡激振动作用机理㊂C H E N[7]使用浸入边界法对流经3个相同的圆柱体的绕流特性进行数值研究㊂夏谦等[8]通过进行风洞试验研究了扰流板对输电塔钢管涡激振动控制效果的影响㊂邓洪州等[9]研究了实际工程中避雷针圆柱体结构由风荷载引起的涡激振动,张文芳[10]分析了风振作用下T M D对高耸结构振动控制机理, R E P E T T O e t a l[11]分析了细长结构在风振作用下的疲劳破坏,L I[12]分析了避雷针结构倾斜的原因,提出了可以有效保证避雷针结构安全的一种新型安装方法㊂景涛等[13]㊁焦晋峰等[14]㊁刘冉等[15]分别采用单㊁双向流固耦合方法分析了避雷针结构的受力性能,得出可以在基本风速内有效抑制涡激振动的结构优化措施㊂C H E N[16]通过数值模拟避雷针结构法兰螺栓,并与试验结合为避雷针结构松动位置的精确定位和松动检测程度奠定了基础㊂国内外研究者主要通过分析风场扰流特性来分析避雷针结构涡激振动问题,仅分析流场作用机理难以判断避雷针结构受力性能,而国内规范‘变电站建筑结构设计技术规程“D L/T5457-2012[17]通过基本风压计算避雷针结构在不同高度下的顺风向风荷载,并没有考虑风绕流对避雷针结构的影响㊂同时,大部分研究者也主要通过模拟脉动风速时程谱研究避雷针结构的顺风向风振响应,忽略了风绕流对避雷针结构连接部位的受力性能影响㊂因此,本文以高度为35m的单钢管避雷针结构为研究对象,基于双向流固耦合方法对其进行三维数值风洞模拟,结合计算流体力学分析该结构的风压力分布模式;探究不同风速对单钢管避雷针结构受力性能影响,并与‘规程“[17]方法进行对比;最后对单钢管避雷针结构进行顺风向与横风向动力响应分析,以期为单钢管避雷针结构设计提供参考依据㊂1双向流固耦合方法1.1流固耦合控制方程空气流动与避雷针结构变形间的流固耦合问题,一般需要采用迭代求解连续性方程㊁动量方程㊁物理守恒定律㊁流固耦合控制方程等,其中双向流固耦合分析方法的流体场和固体场同时进行计算,既考虑流体场对固体场的影响,又考虑固体场对流体场的影响㊂1.1.1空气流体控制方程流体的流动遵循质量守恒定律㊁动量守恒定律和能量守恒定律,主要依靠下列控制方程来定义描述㊂质量守恒方程:ρft+Δ㊃(ρf v)=0.(1)动量守恒方程:474太原理工大学学报第54卷ρf t+Δ㊃(ρf v v -τf )=f f .(2)式中:ρf 为流体密度;t 为时间;v 为流体速度矢量;τf 为剪切力张量,可按τf =(-p +μΔv )I +2μe 式计算;p 为流体压力;μ为动力黏度系数,e 为速度应力张量㊂1.1.2 避雷针结构控制方程由牛顿第二定律可推导得出避雷针结构的物理守恒定律:ρsd ㊃㊃s =Δ㊃σs +f s .(3)式中:ρs 为结构密度;σs 为柯西应力张量;f s 为体积力矢量;d ㊃㊃s 为避雷针结构的加速度矢量㊂1.1.3 流固耦合控制方程流固耦合分析也遵循基本的守恒定律㊂在空气流体和避雷针结构的耦合交界面处,必须满足流固耦合控制方程,以使流体和结构在应力(τ)㊁位移(d )㊁热流量(q )㊁温度(T )等变量处相等或者守恒㊂τf n f =τsn s .(4)d f =d s .(5)q f =q s .(6)T f =T s .(7)式中:f 为流体;s 为固体㊂1.2 双向流固耦合方法验证为验证双向流固耦合方法的准确性,本文采用实体单元建立了单根构架避雷针结构有限元模型[15],风场尺寸上下边界均为10D ,距入口10D ,距出口25D ,D 为构架避雷针结构第五段钢管直径大小,风速选为2m /s 和5m /s ,风向角为0ʎ.通过双向流固耦合方法得到构架避雷针结构不同测点的应变均方值,并结合文献[14-15]模拟结果与风洞试验值进行对比,测点布置及对比结果分别如图1和图2所示,对比发现计算结果与风洞试验值误差均小于20%,证明本文所采用双向流固耦合方法的可行性㊂2 单钢管避雷针结构的数值模拟2.1 单钢管避雷针结构的数值模型采用文献[14]中高度为35m 单钢管避雷针结构,每段钢管的高度尺寸如图3所示㊂弹性模量为206G P a ,泊松比为0.3,钢材密度为7850k g/m 3,结构材质为Q 235B 圆钢管㊂圆钢管间采用法兰圆盘连接,为便于计算,单钢管避雷针结构有限元模型对法兰连接进行简化,底部支座按照理想固接处理㊂结构材料应力-应变关系采用双线性随动强化模型W -1测点W -2测点W -3测点W -4测点W -5测点第一段第二段第三段第四段第五段支座S -1测点S -2测点S -3测点S -4测点S -5测点40 m m40 m m25 m m 20 m m 20 m m 40 m m40 m m25 m m20 m m20 m mW 轴S 轴图1 应变测点布置F i g .1 A r r a n g e m e n t o f s t r a i n m e a s u r i n g po i n t s 以考虑实际材料塑性㊂单钢管避雷针结构的风洞尺寸与上文保持一致,入口边界为速度入口,出口边界为自由出流,上下边界为对称边界[14],设置流固耦合交界面便于后续系统耦合器计算㊂2.2 网格划分流场网格的划分对于反映钝体绕流的特性以及计算效率的快慢至关重要㊂本文采用I C E M C F D软件对流场区域划分以六面体为主的网格,如图4(a )㊁(b )所示,整体网格尺寸采用50mm.为了观察近壁面以及尾流区风速风压变化,在近壁面处设置膨胀层,初始尺寸10mm ,膨胀系数采用1.1.网格质量以q u a l i t y 评价,越接近1则网格质量越好,本文q u a l i t y 大于0.7,网格质量较高㊂单钢管避雷针结构管壁薄而高度大直接划分网格较为困难,为了便于计算对避雷针结构切分后进行网格划分,如图4(c)所示㊂在流场模型及固场模型中分别设置流固耦合交界面,以便后续在S y s t e m C o u p l i n g 模块中通过流固耦合交界面进行双向数据传递㊂2.3 参数设置为了准确模拟出风环境场对避雷针结构横风向涡激振动影响,湍流模型选取S S T k -ω模型,该模型既能在近壁面稳定地计算黏性子层,又能在边界层边缘和自由剪切层中充分模拟湍流流动[8]㊂进口边界的风速根据‘建筑结构荷载规范“(G B 50009-2012)[18]指数风速剖面的基本表达式(8)编写入口风速程序,采用F l u e n t 中U D F 功能输入,湍流动能574 第3期焦晋峰,等:单钢管避雷针高柔结构横风向风致响应研究试验值文献［14］数值模拟结果文献［13］数值模拟结果本文数值模拟结果121086应变/ 10-6W1W2W3W4W5测点号（d ）5 m/s 时W 轴各测点应变值试验值文献［14］数值模拟结果文献［13］数值模拟结果本文数值模拟结果121086应变/ 10-6S1S2S3S4S5测点号（c ）5 m/s 时S 轴各测点应变值试验值文献［14］数值模拟结果文献［13］数值模拟结果本文数值模拟结果3.53.02.52.01.5应变/ 10-6W1W2W3W4W5测点号（b ）2 m/s 时W 轴各测点应变值试验值文献［14］数值模拟结果文献［13］数值模拟结果本文数值模拟结果6543应变/ 10-6S1S2S3S4S5测点号（a ）2 m/s 时S 轴各测点应变值图2 各测点应变值试验与数值模拟结果对比F i g .2 C o m pa r i s o n o f s t r a i n v a l u e t e s t a n d n u m e r i c a l s i m u l a t i o n r e s u l t s a t e a c h m e a s u r e m e n t p o i n t 24 00019 00014 0008 000±030 00033 00035 000GD -1φ45×4GD -2φ83×6GD -3φ152×6GD -4φ219×8GD -5φ299×8GD -6φ380×10GD -7φ450×10（a ）（b ）单位：mm图3 35m 单钢管避雷针结构F i g .3 35m s i n g les t e e l p i p e l i g h t n i n g ro d s t r u c t u r e T u r b u l e n t K i n e t i c E n e r g y㊁湍流耗散率T u r b u l e n t D i s s i pa t i o n R a t e 均设为0.5㊁湍流黏度T u rb u l e n t V i sc o s i t y 设为1.U (z )=U 0ZZ 0α.(8)（a ）流场网格（b ）x -y 截面流场网格（c ）避雷针连接部位网格图4 网格划分F i g.4 G r i d d i v i s i o n 式中:U 为风速,α为地面粗糙度指数,该变电站地貌为B 类,α=0.15,Z 为钢管高度㊂674太原理工大学学报第54卷打开动网格,考虑到圆柱位移较小且存在多个方向位移分量,采用S m o o t h i n g和R e m e s h i n g网格更新方法,更新类型为S y s t e m C o u p l i n g.流体域(F l u e n t)㊁固体域(T r a n s i e n t S t r u c t u r a l)㊁系统耦合器(S y s t e m C o u p l i n g)的计算时间步长设置一致,综合考虑计算精度与计算效率的要求,选择时间步长为0.01s,计算总时间为20s.3数值模拟结果分析3.1风速为25m/s时避雷针结构表面风压力考虑到实际工程中常用设计风速,为分析避雷针结构表面风压分布模式及受力特点,根据式(1)设置数值风洞高度为10m时,入口风速为25m/s.得到圆钢管表面及周围风场风压力分布模式,如图5所示,避雷针结构迎风面受到正风压,两侧壁面及背风面受负风压㊂为提取单钢管避雷针结构表面所受风压值,在避雷针结构表面设置4个测点,分别为迎风面㊁两侧面和背风面的风压力值最大处㊂3.397×1022.314×1021.231×1021.485×10-9.344×10-2.017×102 -3.100×102 -4.183×102 -5.266×102 -6.349×102 -7.432×102测点2测点4测点1测点3风向风压/ Pa图5测点分布F i g.5 D i s t r i b u t i o n o f m e a s u r i n g p o i n t s参照规范‘变电站建筑结构设计技术规程“(D L/T5457-2012)[17]中的式(9),可以求得单钢管避雷针结构不同高度所受风荷载的标准值:w k=βzμsμz w0.(9)式中:w k为风荷载标准值;w0为基本风压,按w0= v201600计算;βz为高度z处的风振系数;μs为风荷载体型系数;μz为风压高度变化系数㊂将数值风洞中单钢管避雷针结构4个测点所受风压值与规范[17]风荷载标准值进行对比,如图6所示,可以看出:1)测点1受顺风向正风压最大为583.8P a,小于风荷载标准值㊂在避雷针结构钢管连接处顺风向风压存在突变现象,在G D-2与G D-3连接处,风压从585P a降至442P a后又增至596P a,在G D-1与测点1风压风荷载标准值800600400200w/Pa50101520253035h/ mGD-7GD-6GD-5GD-4GD-3GD-2GD-1（a）测点1风压（b）测点2、3、4风压1 000500w/Pa测点2风压测点3风压测点4风压风荷载标准值50101520253035h/ mGD-7GD-6GD-5GD-4GD-3GD-2GD-1图6避雷针结构风压变化F i g.6 W i n d p r e s s u r e c h a n g e o f l i g h t n i n g r o d s t r u c t u r eG D-2连接处再次降为425P a.这是由于避雷针结构不同节段连接处圆钢管直径发生变化,使气体倒流形成漩涡导致风压力发生变化;2)测点2㊁4分别为避雷针结构两侧所受横风向负风压,由于避雷针结构是轴对称结构,测点2与测点4所受风压力接近,最大为1.03k P a,绝对值都大于风荷载标准值㊂与顺风向风压值相比,横风向风压力是顺风向风压力的1.72倍,分布规律相似,连接处同样存在突变现象,在节段G D-2与G D-3连接处,风压从994P a降至577P a后又增至1000P a;3)测点3为背风向负风压,相比测点1㊁2㊁4的风压值较小,不同节段连接处风压突变现象不明显㊂3.2钢管避雷针结构表面应力和位移分布图7为风速为25m/s时单钢管避雷针结构的等效应力云图以及位移云图,单钢管避雷针结构位移随高度呈正相关关系,最大位移位于结构顶部㊂避雷针结构所受高应力区域位于不同节段间的连接处,节段G D-2㊁G D-3㊁G D-4㊁G D-5㊁G D-6和G D-7间应力集中位置发生在避雷针结构迎风面风压驻点处,因本文将法兰圆盘进行简化,故数值模拟结果存在一定误差,位移和应力结果偏大㊂774第3期焦晋峰,等:单钢管避雷针高柔结构横风向风致响应研究214.9最大191.03 167.15 143.27 119.39 95.513 71.635 47.757 23.8780最小132.82最大118.07 103.31 88.5573.792 59.034 44.275 29.517 14.7590.000 414 99最小（a）位移云图（b）应力云图图7避雷针结构分析结果F i g.7S t r u c t u r a l a n a l y s i s r e s u l t s o f l i g h t n i n g r o d而G D-1与G D-2节段连接处应力位置位于结构侧面横风向风压驻点处㊂造成单钢管避雷针结构此受力特点的主要原因是随着单钢管避雷针结构高度增加,结构钢管直径减小,结构两侧横风向风压力对避雷针结构的影响增大,当高度大于33m时,横风向风压力对结构的影响最大,导致G D-1与G D-2两个节段连接处侧面横风向驻点处等效应力最大㊂可见,当数值风洞入口风速为25m/s时,横风向风压力对避雷针结构受力性能影响较大,不可忽略㊂3.3不同风速下单钢管避雷针结构受力性能影响为进一步讨论不同风速下横风向风压力对避雷针结构的影响变化,对比数值风洞入口风速为5m/s㊁10m/s㊁15m/s㊁20m/s㊁25m/s㊁30m/s和35m/s 时,单钢管避雷针结构分别在双向流固耦合(方法一)与‘规程“[17](方法二)两种方法下所受最大风压力及位移,如图8所示,可以得出:1)两种方法计算得到单钢管避雷针结构所受风压值以及在风荷载作用下产生的位移均与风速大小呈正相关;2)测点1顺风向最大风压值小于风荷载标准值,二者间的差值率ɤ15%,与风速呈负相关关系;当风速ȡ10m/s时,测点2横风向最大风压值大于风荷载标准值,二者间的差值率在42%,与风速呈正相关关系;3)对比两种方法下避雷针结构所受最大位移,数值风洞计算结果大于规范计算结果,由于避雷针结构受到横风向风压力影响,随风速增加差值增大,最大相差30.6%.综上所述,本文基于数值风洞计算所得单钢管避雷针结构最大顺风向风压值与风荷载标准值差值测点2最大风压测点1最大风压风荷载标准值2 5002 0001 5001 000500w/Pa50101520253035v/ （m·s-1）（a）避雷针结构风压力测点2测点160555045403530252015105差值率/%5101520253035v/ （m·s-1）（b）风压差值率（c）避雷针结构位移方法一方法二600400200位移/mm50101520253035v/ （m·s-1）40图8两种方法结果对比F i g.8 C o m p a r i s o n o f t h e r e s u l t s o f t w o c a l c u l a t i o n m e t h o d s 率小于15%,本文采用的数值模拟分析结果具有一定可靠性;当vȡ10m/s时,数值风洞内横向压力对避雷针结构位移影响较大,建议采用本文所用双向流固耦合方法进行验算,以保证避雷针结构设计结果的合理性以及在使用过程中的安全性㊂4单钢管避雷针结构动力响应分析4.1单钢管避雷针结构自振模态分析为进一步分析横风向风压对单钢管避雷针结构动力响应的影响,现对单钢管避雷针结构进行模态分析㊂采用A N S Y S W o r k b e n c h软件M o d a l模块,网格划分和接触设置与前面的数值模拟设置保持一874太原理工大学学报第54卷致,得到了单钢管避雷针结构的前8阶固有频率与振型,如表1所示,由于避雷针结构为轴对称结构,所以每2阶振型相同,固有频率接近㊂避雷针结构后6阶自振频率大于1H z,发生高阶弯曲振动现象,为避免在运营过程中发生异常振动引起的安全事故,应避免避雷针结构振动频率与后6阶自振频率接近产生共振㊂表1单钢管避雷针结构振型及频率T a b l e1 V i b r a t i o n m o d e a n d n a t u r a l f r e q u e n c yo f s i n g l e s t e e l t u b e l i g h t n i n g r o d阶数固有频率/H z振型特点10.64绕y轴弯曲摆动20.64绕x轴弯曲摆动31.72绕y轴一阶弯曲振动41.75绕x轴一阶弯曲振动53.70绕y轴二阶弯曲振动63.76绕x轴二阶弯曲振动76.07绕y轴三阶弯曲振动86.15绕x轴三阶弯曲振动4.2单钢管避雷针结构动力响应分析以风速25m/s为例,在单钢管避雷针结构最大位移处提取顺风向与横风向位移随时间的变化曲线,如图9(a)㊁(c)所示,可以看出单钢管避雷针结构顺风向位移随时间发生周期性变化,幅值由414.9 mm逐渐变为214.9mm并趋于稳定,横风向位移幅值为5.73mm,相比顺风向位移,幅值较小但振动较为复杂㊂通过拾取傅里叶变换(F F T)后的峰值频率,发现结构顺风向振动在f=0.65H z频率下的响应较为显著,横风向振动在0.3㊁0.65㊁1.95H z 频率下的响应较为显著,如图9(b)㊁(d)所示㊂顺风向振动与横风向振动都以f=0.65H z频率为主,与单钢管避雷针结构通过模态分析得出的一㊁二阶自振频率f=0.64H z接近㊂为了进一步分析避雷针结构在不同风速下动力响应变化,提取在风速为5m/s㊁10m/s㊁15m/s㊁20 m/s㊁25m/s㊁30m/s和35m/s时避雷针结构顶部最大位移处顺风向与横风向位移谱,如图9(e),发现随着风速增大避雷针结构顺风向与横风向振动仍然是在0.65H z频率下的响应最为显著,最大振幅与风速成正比㊂当风速为20m/s时,横风向振动在0.3H z㊁0.65H z频率下的响应较为显著,而当风速为25m/s时,横风向振动在0.3㊁0.65㊁1.95H z频率下的响应较为显著,证明当风速大于20m/s时,横风向振动发生与避雷针结构高阶模态自振的现象,不利于结构安全㊂4.3单钢管避雷针结构绕流形态风流经单钢管避雷针结构产生漩涡脱落现象,为进一步探索风荷载对避雷针结构振动效应的影响,根据卡门涡街理论,单钢管避雷针结构绕流的形态可以根据公式(10)计算雷诺数R e来判断:R e=6900v D.(10)式中:D为结构截面直径,v为风速㊂根据公式(10)计算得到,当入口风速为25m/s 时避雷针结构不同节段钢管雷诺数,如表2所示, G D-1-G D-7节段钢管雷诺数呈现增大趋势,则避雷针结构尾流区域增大且涡脱频率增大㊂分别计算在风速为5~35m/s时G D-7节段钢管雷诺数,如表3所示,G D-7节段钢管R e都小于3.0ˑ105.可见,在风速为5~35m/s时,单钢管避雷针结构尾流漩涡呈周期性脱落,处于亚临界微风共振,建议对该避雷针结构采取防振措施㊂表2单钢管避雷针结构雷诺数T a b l e2 R e y n o l d s n u m b e r o f s i n g l e s t e e l p i p el i g h t n i n g r o d s t r u c t u r e节段h/m v/(m㊃s-1)D/mm R eG D-13430.03459326.6G D-231.529.698317006.5 G D-32729.0115230432.5 G D-421.528.0421942373.9 G D-516.526.9529955601.1 G D-61125.3638066493.9 G D-7421.7945067656.7表3不同风速下G D-7节段雷诺数T a b l e3 R e y n o l d s n u m b e r o f G D-7s e g m e n t sa t d i f f e r e n t w i n d s p e e d sv/(m㊃s-1)5101520253035 R e/1041.42.74.15.46.78.19.7 5结论本文采用A N S Y S W o r k b e n c h有限元软件针对单钢管避雷针结构进行了三维数值风洞模拟,分析不同风速下单钢管避雷针结构受力特点,并与规范规定数值进行对比,最后对其进行横风向与顺风向动力响应分析,主要结论如下:1)在入口风速为25m/s的数值风洞内,单钢管避雷针结构两侧所受最大横风向风压力为1.03 k P a,是顺风向风压力的1.72倍,且在钢管连接处风压力突变现象显著,在节段G D-2与G D-3连接处,风压从994P a降至577P a后又增至1000P a.2)当风速大于10m/s时,横风向风压对避雷974第3期焦晋峰,等:单钢管避雷针高柔结构横风向风致响应研究400200y / m m1020t / s（a ）顺风向位移（b ）顺风向位移振幅80757065605550454035302520151050振幅/ m m2频率/ Hz4f ＝0.65 Hz （c ）横风向位移20-2-4-6x / m m10t / s20（d ）横风向位移振幅321振幅/ m m2频率/ Hz4f 2＝0.65 Hzf 1＝0.3 Hz f 3＝1.95 Hz（e ）不同风速下横风向位移振幅2.42.01.61.20.80.40振幅/ m m 12345频率/ Hzv ＝15 m/sv ＝20 m/s v ＝25 m/s v ＝30 m/s速度/（m ·s -1）振幅/mm 对应频率/Hz151.190.65202.180.65252.470.65302.590.65图9 单钢管避雷针结构顶部最大位移时程图F i g .9 T i m e -h i s t o r y d i a g r a m o f m a x i m u m d i s p l a c e m e n t a t t h e t o p o f s i n g l e s t e e l p i p e l i g h t n i n g ro d s t r u c t u r e 针结构影响不可忽略,结构在数值风洞内所受最大顺风压小于风荷载标准值,差值率小于15%,横风向风压值大于风荷载标准值,差值率约为42%,而结构顶端位移与按‘规程“[17]方法计算结果相比增长30.6%.3)当风速大于20m /s 时,避雷针结构顺风向振动以0.65H z 频率为主,横风向振动在0.3㊁0.65㊁1.95H z 频率下的响应较为显著,与避雷针结构高阶自振频率接近,避雷针结构易发生高阶弯曲振动,存在一定的安全隐患㊂参考文献:[1] 王建,邓鹤鸣,刘劲松,等.风害区域750k V 变电站构架避雷针变形分析及应对措施[J ].电瓷避雷器,2017,276(2):14-18.WA N G J ,D E N G H M ,L I U J S ,e t a l .T h e D e f o r m a t i o n a n a l y s i s a n d c o u n t e r m e a s u r e s o n t h e f r a m e l i g h t n i n g ro d o f 750k V s u b s t a t i o n i n t h e w i n d d a m a g e a r e a s [J ].I n s u l a t o r s a n d S u r ge A r r e s t e r s ,2017,276(2):14-18.[2] 孙涛.一起架构避雷针断裂故障原因分析[J ].电磁避雷器,2017,276(2):49-52.S U N T.A c a u s e a n a l y s i s o f f r a c t u r e f a i l u r e w i t h a r c h i t e c t u r e t y p e l i g h t n i n g r o d [J ].I n s u l a t o r s a n d S u r ge A r r e s t e r s ,2017,276(2):49-52.[3] 张睿,娄敏,王晓凯,等.错列双圆柱涡激振动干涉数值模拟[J ].石油机械,2022,50(9):85-92.Z HA N G R ,L O U M ,WA N G X K ,e t a l .N u m e r i c 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s i s o f s t r u c t u r a l m e c h a n i c a l p e r f o r m a n c e o f f r a m e d l i g h t n i n g r o d u n d e r s t r o n g w i n d[J].C h i n a S c i e n c e p a p e r,2019,14(10):1090-1095.[14]焦晋峰,胡帅,刘勇,等.基于流固耦合理论的独立避雷针P-Δ效应分析[J].中国科技论文,2021,16(10):1046-1054.J I A O J F,HU S,L I U Y,e t a l.A n a l y s i s o f P-Δe f f e c t o f i n d e p e n d e n t l i g h t n i n g r o d b a s e d o n f l u i d-s t r u c t u r e i n t e r a c t i o n t h e o r y [J].C h i n a S c i e n c e p a p e r,2021,16(10):1046-1054.[15]刘冉.基于双向流固耦合的变电构架避雷针结构风振响应分析[D].郑州:郑州大学,2019.[16] C H E N G.D y n a m i c s m o d e l i n g a n d e x p e r i m e n t a l m o d a l a n a l y s i s o f b o l t l o o s e n i n g f o r l i g h t n i n g r o d[J].J o u r n a l o f V i b r o e n g i-n e e r i n g,2020,22(3):657-671.[17]国家能源局.变电站建筑结构设计技术规程:D L/T5457-2012[S].北京:中国计划出版社,2012.[18]中华人民共和国住房和城乡建设部,中华人民共和国国家质量监督检验检疫总局.建筑结构荷载规范:G B50009-2012[S].北京:中国建筑工业出版社,2012.(编辑:万佳)184第3期焦晋峰,等:单钢管避雷针高柔结构横风向风致响应研究。

热重分析法对废旧电路板热解过程动力学和热力学分析

第15卷第1期2024年2月有色金属科学与工程Nonferrous Metals Science and EngineeringVol.15，No.1Feb. 2024热重分析法对废旧电路板热解过程动力学和热力学分析阳宇1，夏勇1，王君2，欧阳少波*1，熊道陵1，李立清1（1.江西理工大学材料冶金化学学部，江西赣州 341000； 2.商洛学院化学工程与现代材料学院，陕西省尾矿资源综合利用重点实验室，陕西商洛 726000）摘要：废旧电路板（SPCB ）是一种典型的有机废弃物，可通过热解技术实现其资源化利用。

采用热重分析技术（TGA ）对其热解特性进行研究，揭示热解过程反应动力学和热力学。

实验在氮气气氛下，考察了不同升温速率（5、10、15 ℃/min ）对SPCB 热失重特性的影响，结果表明热解过程主要发生在250 ~ 400 ℃温度区间，随着升温速率增大，SPCB 热失重（TG ）曲线逐渐向高温方向偏移，在对应的热失重速率（DTG ）曲线中，存在一个明显的失重峰，且峰值温度不断增加，热滞后现象显著。

采用Flynn-Wall-Ozawa （FWO ）模型、Kissinger-Akahira-Sunose （KAS ）模型和Friedman （FM ）模型进行动力学分析，拟合得到平均表观活化能（E a ）分别为168.46、167.31、234.84 kJ/mol ，活化能均随转化率增加而相应增大。

利用FWO 模型对热力学参数进行计算，在相同升温速率下，随着转化率的增大，吉布斯自由能变（ΔG ）逐渐降低，对应的焓变（ΔH ）和熵变（ΔS ）不断增加；在相同转化率时，ΔH 和ΔS 随升温速率增加稍有降低，而ΔG 逐渐增加。

关键词：废旧电路板；热解特性；动力学；热力学中图分类号：TQ524；X784 文献标志码：AKinetics and thermodynamics during pyrolysis of scrapprinted circuit board by TGAYANG Yu 1, XIA Yong 1, WANG Jun 2, OUYANG Shaobo *1, XIONG Daoling 1, LI Liqing 1（1. Faculty of Materials Metallurgy and Chemistry ， Jiangxi University of Science and Technology ， Ganzhou 341000， Jiangxi ， China ； 2. Shanxi Key Laboratory of Comprehensive Utilization of Tailings Resources ， College of Chemical Engineering and Modern Materials ，Shangluo University ， Shangluo 726000， Shanxi ， China ）Abstract: Scrap printed circuit board (SPCB) is a typical organic waste, which could be utilized as a resource by pyrolysis technology. The pyrolysis characteristics of SPCB were studied by thermogravimetric analysis (TGA) to reveal the reaction kinetics and thermodynamics during the pyrolysis process. Under N 2 atmosphere, the effects of different heating rates, e.g. 5 ℃/min , 10 ℃/min and 15 ℃/min , on the thermal decomposition behavior of SPCB were investigated in detail. The results observed showed that the pyrolysis process was mainly occurred in the收稿日期：2022-12-01；修回日期：2023-04-09基金项目：江西省自然科学基金资助项目（2020BAB214021）；江西省教育厅科学技术研究资助项目（GJJ200809）；陕西省自然科学基金资助项目（2021JQ-840）；江西理工大学大学生创新创业训练资助项目（DC2022-004）通信作者：欧阳少波（1986—　），博士研究生，讲师，主要从事炭材料应用和废弃资源热转化利用方面的研究。

西北大学最好的专业

西北大学最好的专业篇一：西北大学排名西北大学（Northwestern University），简称NU或NWU，1851年创立，是享誉世界的美国顶尖私立研究型大学，十大联盟高校。

西北大学Northwestern University 2015年在最权威的《美国新闻和世界报道》(US News)美国大学排名上位列第13位，2015年泰晤士高等教育（Times）全球大学排行榜排名第21位。

西北大学是一个大规模的研究大学，其学生大多数寄宿。

中北部院校协会和相应的美国化学、心理学、商业、教育、新闻业、音乐、工程、法学和医学专业组织认可其130多个本科项目以及70个研究生和专业项目。

在2006年至2007年学期中西北大学授予了2089个学士学位、2665个硕士学位、462个博士学位和416个专业学位。

留学360介绍：本科项目四年，有大学大多数学生，强调“艺术和科学/专业”。

每个学校的系自己设立学位要求。

每学年分三学期，每学期约十周，三个学期从每年的九月末开始，六月初结束。

一般本科生需要在毕业前至少学习了12个学期，但是西北大学的学生业可以通过加速、荣誉和混合医学、科学、数学、工程和新闻学科。

博士研究生项目与本科项目一起进行。

本科毕业生班中按照成绩平均积点最高的3%被授予最优等，其次的5%被授予极优等，在其次的8%被授予优等。

西北大学也有荣誉学术协会。

至今为止西北大学向不同人物授予了520个名誉学位。

学生情况在2006至2007年学术年西北大学招收了8284名本科生、8249名研究生和1495名专业学生。

本科生中51.6%是女生，他们来自美国50个州和其它50个国家。

收录被定义为“比较选择，较少转入”。

2011届（2007年入学）的本科生有21,930名学生报名：5872名被接受（26.8%）、1981名征收（33.7%）还有96.3%的降级学生。

86%的学生在四年后毕业，六年后93%的学生毕业。

教学资源西北大学共设有11间图书馆，其中以埃文斯通校区的主图书馆最具规模，总藏书超过460万本，共收藏逾4万本杂志与期刊，学生可以经由电脑化的图书馆设备查知资料的所在处。

化学检索网站集

NO.1（1）超星——南大镜像点在超星网站上，可以下载或是阅读相关书籍。

（2）Nature官网进入该数据库网站后，在Browse一栏中点击subject，从而选择感兴趣的学科。

进行检索时，可点击“advanced search”，进入检索界面，可输入作者、题目、期刊名称、出版时间等进行检索，还可按学科分类搜索。

（3）Science官网（）点击science journal可以查看到science杂志的内容，同时还可以像nature一样进行检索。

（4）中经网，点击进入中国经济统计数据库，这里有详尽的关于中国经济发展的各项统计数据，一目了然，比如点选左边栏的经济地图：（5）维普网，如进入南大镜像点，只要知道自己想要找的期刊名称或是作者，出版社就可以找到这本期刊。

也可以利用期刊导航，找到自己想要找的东西。

（6）BEILSTEIN化学资料数据库NO.2美国国家标准与技术研究所NIST官网的使用Nist time:数理科学与化学：化学：包括分析化学，化学原理与工程，化学分析，有机分析化学等许多有关化学的分支。

在其中我们可以查看许多想看到的最新知识和新发表的论文，对开阔我们化学视野有很大的帮助。

在右边有一个NIST most popular,其中的chemistry webbook是一个相当实用的搜索引擎。

这是一个相当大的数据库。

可以让我们通过一个化合物的一些简单的性质（如化学式等），来查看着整个物质的一系列性质（如某些特定的理化性质，一些本身的属性常数以及各种谱图等）。

回到左边，其中有一个energy,在其中我们可以搜索到各种当代所开发的能源信息（如电能，核能等），另外其中也包括许多新能源，能源转换，储存和运输等一系列能源信息。

在下面有一个materials science，其中介绍了各种材料的信息。

如：生物材料，混合材料，纳米材料等一系列过去的材料信息和一些新材料信息。

具体操作为：输入网址：,打开链接。

国开电大本科《理工英语4》机考第三大题阅读理解选择总题库[珍藏版]

国开电大本科《理工英语4》机考总题库[珍藏版]说明：资料整理于2023年8月，适用于国开电大一平台期末机考考试。

第三大题阅读理解选择题首字母AAccording to experts,the advantage of modified food is that it helps in preventing the occurrence of allergies and also has along shelf life.However,a major portion of the population is against the consumption of genetically modified food and is concerned about its disadvantages.If you are also confused about the consumption of genetically modified food,read through the pros and cons given below and decide for yourself.Advantages of Genetically Modified Foods●One of the most prominent advantages of genetically modified food is that it helps in controlling the occurrence of certain diseases.Certain foods cause allergy to people.Their genetic modification alters the DNA system of these foods,thereby making them non-allergic.●Another major advantage of such type of foods is that they grow faster than their traditionally grown counterparts.As a result,there is greater productivity and more food.●A person need not bother about any additional costs,such as buying chemicals and pesticides,when it comes to genetically engineered food.The food is naturally pest-resistant.●Farming these foods can be a great way to fight world hunger.Since these crops grow faster or more effectively,increased production would help countries wherein crops may not normally prosper because of less than desirable environmental conditions.●The increased shelf life of these food products helps in reducing the quantity of rotten food.Disadvantages of Genetically Modified Foods●The biggest disadvantage of genetically modified food is that they have harmful effects on the human body.The consumption of these genetically engineered foods can lead to development of diseases that are immune to antibiotics.●Chances of developing cancer are high in people who regularly consume engineered food.●Since it is an unnatural way of producing foods,there is an increased health hazard such as allergens,transfer of antibiotic resistance markers and unknown effects.●Since the production of engineered food involves infusing animal genes in the crops and tampering with nature,it might not be good for consumption in the long run.特别提醒：本题共5个小题,需要拉动答题框右边的滚动条使5个试题显示出来做答！！[单选题]◆How does genetically modified food control the occurrence of certain diseases?A.By cross-pollinating.B.By conventional crossbreeding.C.By altering the DNA system of these foods.[答案]C[单选题]◆Do farmers need to buy any chemicals and pesticides if they plant genetically modified food?A.Yes,they need to.Because the food is not resist to pests.B.No,they don’t need to.Because the food is naturally pest-resistant.C.No,they don’t need to.Because the chemicals and pesticides are provided by the government.[答案]B[单选题]◆Which statement is not the advantage of genetically modified food?A.It may have harmful effects on human body.B.Genetically modified food grows faster than their traditionally grown counterparts.C.Farming genetically modified food can help fight world hunger.[答案]A[单选题]◆What would happen to a person if he regularly consume genetically modified food?A.He would get cold.B.He would lose some weight.C.He would have cancer.[答案]C[单选题]◆Which of the following would be the best title for this passage?A.Can Genetically Modified Foods Combat World Hunger?B.Genetically Modified Mood：Our Answer Is No.C.Genetically Modified Foods：Pros And Cons[答案]C首字母II am very happy to share my story about breast enlargement in Thailand.Anyone who is not sure about breast enlargement should read this story first.Firstly,I was amazed at the level of care I received at the Thailand private hospital.It was like being in a luxury hotel.The nursing staffs were also better than those who I have ever met in all my years in America.Not only were they professional,but kinder and more patient than Western nurses.The hospital food was excellent,so I was able to choose from a large and varied Menu.In my private room,there was cable T.V.,a fridge,a phone,and impressive views of Bangkok(曼谷).My Translator was able to communicate with me,and the plastic surgeons arranged the whole operation without me lifting a finger.The operation cost me a third of the price of the U.K.With the low cost of the air tickets and a holiday,it worked out at about half UK’s price,because the cost in Thailand is so cheap.Combining a plastic surgery with a holiday in an amazing place is an unforgettable experience.From the moment I arrived in Bangkok airport,I felt relaxed and welcomed by the Plastic Surgery&Holiday team,it made me feel that I had friends here already.特别提醒：本题共5个小题,需要拉动答题框右边的滚动条使5个试题显示出来做答！！[单选题]◆Where did the author have her breast-enlargement operation?A.In Thailand.B.In America.C.In U.K.[答案]A[单选题]◆Was the author satisfied with the nursing staffs for her?A.No,because they were no better than America nurses.B.Yes,because they were more patient than Western nurses.C.No,because the care was very poor.[单选题]◆Which of the following statement is TRUE?A.The author was content with the food in the hospital.B.When the author was in the hospital,she lived in a public room.C.There was cable T.V.,a bridge and a phone in the author’s room.[答案]A[单选题]◆What does the underlined phrase lifting a finger mean in paragraph three?A.Doing something with only one finger.B.Helping with something.C.Carrying something.[答案]B[单选题]◆Why did the author think her experience unforgettable?A.Because she had an operation there.B.Because she was satisfied with everything there.C.Because she was satisfied with the service and price there.[答案]CIf you think3D printing is only good for making flimsy paperweights.then you’re pretty much right.However.a group of audacious Dutch architects have already begun3D printing an entire canal house in Amsterdam.Is the first3D printed house a gimmick?Definitely!Is it an experiment that pushes the possibilities for3D printing technology and architecture?Maybel3D Print Canal House is the brainchild of DUS Architects.“KamerMaker’.Dutch for’room maker”,is their giant printer built inside a shipping container.Just a few weeks ago,KamerMaker began printing plastic furniture and walls at an empty canal-side lot in northern Amsterdam.Smaller versions of the unusual honeycomb walls have been tested on normal desktop printers,and everyone just needed to scale it up.Well,if only it were that easy.The printer did not always manage to spread the plastic evenly,making some of the ribs of the honeycomb structure of the block uneven.reported ARN（Australian Radio Network,to the surprise of no one who has used a 3D printer.But the architects remain optimistic.The first few printed blocks are meant to be test pieces as they improve the process.It takes about a week to print a3-meter high block right now.The project’s leader hopes to eventually get that down to two hours and finish the first of12rooms in a year.and the entire house in less than3years. Ultimately,3D Print Canal House is an architectural research project,one that is very much being conducted in the public eye:you can actually buy tickets to visit the construction site for2、50Euros.The top floors will become more omate.for example.as newer techniques are incorporated.They’ll explore the possibilities of3D printing.like the honeycomb walls or an entire room recycled.redesigned,and built anew.Nobody’s going to move into a3D printed house soon,but,if any on ever does.something might be learned from this experiment by the canal.特别提醒:本题共5个小题,需要拉动答题框右边的滚动条使5个试题显示出来做答！！[单选题]◆What have the Dutch architects begun to use the3D printer to do according to the passage?A.To make heavy paperweights.B.To print the unusual honeycombC.To print an entire canal house.D.To build a shipping container.[答案]B[单选题]◆Where did KamerMaker begin printing plastic furniture and walls several weeks ago?A.It was inside a shipping container in Amsterdam.B.It was at an empty canal-side lot in northern Amsterdam.C.It was in a canal house in Amsterdam.D.It was in a room.[答案]B[单选题]◆What is the weakness of the3D printer mentioned in the passage?A.It cannot always spread the plastic evenly.B.It needs to be shortened.C.It cannot make the ribs of the honeycomb structure.D.It can print anything smoothly.[答案]B[单选题]◆How long will it take for the3D printer to make the canal house in Amsterdam?A.A week.B.Two hours.C.More than3years.D.Less than3years.[答案]A[单选题]◆Which of the following statements is WRONG according to the passage?A.This canal house is being built in the public eye.B.The top floors of the canal house will be more decorated.C.Some one is going to move into this canal house soon.D.One can visit the construction site for2.50Euros[答案]CImagine you sitting on your front garden admiring the shining sun when your neighbor comes with that annoying car with the noisy sound and the exhaust pipe blowing out the horrible black smoke.What are you going to do about it？In our modem days,too many people depend on their cars to get to work or to drop off their children to school.However,is it safe to have an increasing number of cars on our roads？Research shows that cars create serious pollution.Exhaust from all combustion engines produce harmful effects on the health of both car users and all innocent walkers.Cities have become islands of toxic chemicals from the unrestrained use of vehicles burning fossil fuels.The harmful health effects of car exhaust are pervasive and difficult to measure.For example,people with asthma would suffer with attacks due to the pollution.The world wild life also suffers from the cars’toxic emissions.No matter how much manufacturers try to make cars environmentally friendly it will damage our earth in one way or another.Additionally cars are too dangerous for our community.Careless drivers put themselves and others in danger.Cars are critical to walkers especially to children if the driver is not looking on the road or somehow distracted Have you known someone whose toes or feet have been run over by cars while crossing the street？Lastly.cars create social problems,which could lead to poor health.A few drivers suffer“Road Rage”and put themselves.loved ones and others in a threatening situation.Some cars create disturbing noises,which disturbs people living near highways,freeways,etc.not to get enough sleep.People depend on their cars so much that they forgot to exercise their bodies and end up being obese or having a heart problem.As a result of the excessive number of cars on our roads,everyone’s life is in danger.In order to create an environmentally friendly and safe world,it is necessary for each country to limit the permits in number to control regional air pollution.Second,car manufacturers should try to improve the efficiency of vehicles,such as finding solutions to emissions of combustion engines,developing new power sources such as new fuels,natural gas.Third,try to improve efficiency of traffic by setting up dedicated bus lanes and giving priority to car-pools and vehicles with3or more passengers.Besides,traffic can be scheduled;for example,commercial traffic atnight;large companies can shift working hours and decentralize administrative operations.特别提醒：本题共5个小题,需要拉动答题框右边的滚动条使5个试题显示出来做答！！[单选题]◆Exhaust from cars is________.A.harmlessB.pollutiveC.not serious[答案]B[单选题]◆In the author’s view,it is________to make cars be friendly to environment.A.impossibleB.feasibleC.hopeful[答案]A[单选题]◆________will be the major victims in the car accident.A.WalkersB.ChildrenC.Car-drivers[答案]B[单选题]◆Cars caused some social problems EXCEPT________.A.obesityB.a quick temperC.employment[答案]C[单选题]◆Which of the following is NOT TRUE as to handling car problems？A.Reducing the number of cars.ing a car in the restricted areaC.Finding alternative fuels.[答案]BIn the grass,a baby duck was hatched(孵化)out in a college biology lab with a backward left foot.At the time,it probably wouldn’t have survived,if Mike Gary didn’t recommend a proper operation to cut off that bad foot.Months after the healing process,engineers at Nova copy Company produced a3D printed model that would be used to create a prosthetic(修复的)foot for the duck.Considering that ABS plastics were not flexible enough for this type of exercise,the Nova copy company made a three-dimension ally modeled foot made of silicone,with the hope to create a permanent prosthesis(假肢)for the duck.It took just13hours to produce.This3D prosthesis demonstrated the3D technologies can be used not only for human application,but also in foreign subjects such as animals and other medical treatments.特别提醒：本题共5个小题,需要拉动答题框右边的滚动条使5个试题显示出来做答！！[单选题]◆Where was the baby duck hatched out?A.In a college biology lab.B.In a back yard.C.In Nova copy Company.[答案]A[单选题]◆What was wrong with the baby duck?A.It didn’t survived.B.It was born with a backward left foot.C.Mike Gary cut off that bad foot.[答案]B[单选题]◆Could ABS plastics be used to produce a3D printed model that would be used to create a prosthetic foot for the duck?A.No,because ABS plastics were not flexible enough.B.Yes,but it could only be produced by Nova copy Company.C.Yes,because it was made of silicone.[答案]A[单选题]◆How long did it take to create a permanent prosthesis for the duck?A.10hours.B.13hours.C.30hours.[答案]B[单选题]◆What did the last sentence of this passage indicate?A.3D technologies can be used only for human application.B.3D technologies can be used only for foreigners.C.3D technologies can be used to human,animals and other medical treatments.[答案]C首字母MMy hero is a person who has given me so many things,who has taught me about everything,and who has shown me how beautiful life is.And gradually as I get older and I grow up,my hero has opened my eyes to the fact that life is not always beautiful and happy like a fairy tale,but life is much more than that.My hero has explained to me that life can be very hard.Everyone must struggle hard to make all their dreams come true and to be a successful person.Maybe,because my her olives so close to me,I haven’t realized that this person has inspired me so much.My only true heroism y mother.She was born in Jakarta,on the1st of July.My mother is the youngest child in her family.She has two sisters,who always love and take care of her.Maybe,because of that,she becomes a cheerful,kind,friendly,and love able person.She wants everybody to feel comfortable when they are around her.My mother likes to study and to read everything,from books to newspapers.Everyone really likes to talk and chat with her,so she has many friends.My mother believes all you need is to be a hard-working person who always wants to study hard,so that you can be a successful person.She says that many people around her have succeeded because they have studied and worked hard.特别提醒：本题共5个小题,需要拉动答题框右边的滚动条使5个试题显示出来做答！！[单选题]◆If a person wants to succeed in his life,he________.A.should listen to a fairy tale everydayB.must dream a good dream everydayC.has to work hard all his life[答案]C[单选题]◆The underlined word“inspired”in Paragraph2may have the same meaning as“________”.A.encouragedB.showedC.cared[答案]A[单选题]◆The writer’s mother becomes a love able person becauseA.she is the youngest in the familyB.her two sisters love her very muchC.she feels comfortable in her family[答案]B[单选题]◆From the third passage,We can infer(推测)that the writer________.A.is a friendly person like his motherB.has many friends to talk withC.knows the meaning of success[答案]C[单选题]◆Which of the following is the best title for the reading?A.Study well!B.What a beautiful life!C.My mother,my hero.[答案]C首字母RRoby Mini is just40centimeters tall,has a large round screen for ahead and has been designed to help senior citizens living alone.Manufactured by robotics company Shanghai PT Info,the brightly colored robot,which costs 5,000yuan($790),was launched on Aug14to help entertain and monitor elderly people.In Shanghai last year,the number of registered residents at least60years old was4million.That was nearly30 percent of the population.By2018,the figure is projected to rise to5million.With many living alone,robots such as Roby Mini can help playa crucial role in caring for the elderly.“It will change the way people interact with digital products,”Hong says.Founded in May,Shanghai PT Info had already done the groundwork.In fact,the research team spent three years developing the speech recognition system before the firm was officially launched.With360-degree wheels hidden under its body,Roby Mini can follow a person through face recognition and strike up a conversation,tell jokes or provide information.The robot also works as a computer terminal,supplying weather information,ordering groceries online and even booking taxis.Roby Mini can be connected to other gadgets as well,such as smart wristbands or magnetic devices on doors.Roby Mini can also connect an elderly owner to a doctor through its high-definition screen.Already Shanghai PT Info is talking to three community hospitals in Shanghai’s Min hang district.Since the robot is linked to the Internet,it can support long-distance audio and video calls.Mass production started this month and Shanghai PT Info plans to manufacture200,000units this year.But the future is not easy for Shanghai PT Info.Earlier this year,Flying wings Intelligent Robot Technology(Shanghai)introduced a machine with sensors that will ring an alarm when an elderly person falls down.Tianjin Shangjiu Sheng yuan Technology Group also developed a robot for seniors in2014.Owners can turn on the lights and air-conditioning units by pressing buttons on the machine.It can also remind elderly owners to take pills,and inform them of hospital checkups and family birthdays.特别提醒：本题共5个小题,需要拉动答题框右边的滚动条使5个试题显示出来做答！！◆Roby Mini is the name of_________.A.a robotics companyB.a robotC.a senior citizen living alone[答案]B[单选题]◆Roby Mini is designed to_________.A.help look after children living alone in senior high schoolB.help entertain and monitor senior citizensC.change the way people interact with digital products[答案]B[单选题]◆According to this passage,the number of registered residents at least60years old will be___.A.4million next yearB.30percent of the populationC.increase to5million by2018[答案]C[单选题]◆The writer thinks“the future is not easy for Shanghai PT Info”because_________.A.there are too many elder people in ShanghaiB.Roby Mini can not ring an alarm when an elderly person falls down.C.the company will face tough competition in the marketplace[答案]C[单选题]◆The writer thinks“the future is not easy for Shanghai PT Info”because_________.A.there are too many elder people in ShanghaiB.the company will face tough competition in the marketplaceC.Roby Mini can not ring an alarm when an elderly person falls down[答案]B[单选题]◆The best title for this passage would be“_________”.A.How to Use a RobotB.Elder People Increase in ShanghaiC.Robot Gives Help to Older People[答案]C首字母TThere are three kinds of goals:short-term,medium-range and long-term goals.Short-term goals are those that usually deal with current activities,which we can apply on a daily basis.Such goals can be achieved in a week or less,or two weeks,or possibly months.It should be remembered that just as a building is no stronger than its foundation,our long-term goals cannot amount to very much without the achievement of solid short-term goals.Upon completing our short-term goals,we should date the occasion and then add new short-term goals that will build on those that have been completed.The intermediate goals build on the foundation of the short-term goals.They might deal with just one term of school or the entire school year,or they could even extend for several years.Any time you move a step at a time,you should never allow yourself to become discouraged or overwhelmed.As you complete each step,you will enforce the belief in your ability to grow and succeed.And as your list of completion dates grows,your motivation and desire will increase.Long-term goals may be related to our dreams of the future.They might cover five years or more.Life is not a static thing.We should never allow a long-term goal to limit us or our course of action.特别提醒：本题共5个小题,需要拉动答题框右边的滚动条使5个试题显示出来做答！！[单选题]◆Short-term goals are the ones that________.A.motivate you over the long haulB.keep you engaged on a daily basisC.might be measured for many years[答案]B[单选题]◆The medium-range goals are built upon________.A.belief and successB.the motivation and desireC.the completion of the short-term goals[答案]C[单选题]◆Once we set ourselves long-term goals,________.A.we should stick to them until we complete themB.we may change our goals as we have new ideas and opportunitiesC.we had better wait for the exciting news of success[答案]B[单选题]◆What does the underlined word“static”mean in the last paragraph?A.movingB.developingC.not moving[答案]C[单选题]◆Which of the following statements is TRUE according to the passage?A.Short-term goals all help in achieving your long-term goals.B.Any time you move a step at a time,you may become discouraged.C.Life is a static thing,thus never allowing a long-term goal to limit us.[答案]A首字母WWhen computer servers operate a complex program,they can get very hot.Cooling the servers can be costly.So researchers asked what would happen if the heat created by the servers could be captured and used?Data centers of large Internet companies such as Google and Microsoft have thousands of computer servers.As these servers process information,they create large amounts of heat,so they need huge cooling systems,These systems send the heat into the air.The Dutch company Nerdalize thinks paying for electrieity to operate the servers and then paying again to cool them is a waste of energy.So it developed a device called the e-Radiator.It is a computer server that also works as a heating source.Boaz Leupe is the chief executive officer of Nerdalize,He says the e-Radiator saves money because companies don’t have to pay to cool their servers.“The kilowatt(千瓦)hour you are using is used twice-once to heat the home and once to compute the client’s task without the cooling overhead.”He says five homeowners in the Netherlands are testing the heating device in their homes.“We reimburse the electricity the server uses,and that we can do because of the computer clients on the other side,and,in that way,homeowners actually get heating for free,and computer users don’t have to pay for the overhead of the data center.”Jan Visser is one of the participants in the year-long experiment.He says the amount of heat produced by the e-Radiator into room depends on the work being done by the computer server.He says it can not be used as theprimary source of heat.But he is ready to try it.He says if it provides enough warmth,he will be able to use his home’s heating system less,which will save him money.Nerdalize says e-Radiators create heat temperatures of up to55℃.It says the devices could save users up to$440in heating costs a year.特别提醒：本题共5个小题,需要拉动答题框右边的滚动条使5个试题显示出来做答！！[单选题]◆Why did researchers ask what would happen if the heat created by the servers could be captured and used?A.Because computers can get very hot.puter servers is a complex program,C.Cooling computer servers costs a lot of money.[答案]C[单选题]◆The computer servers in large Internet companies such as Google and Microsoft can________.A.create large amounts of informationB.create large quantity of heatC.manage the huge cooling systems[答案]B[单选题]◆Nerdalize developed the e-Radiator because_________.A.e-Radiator cost less energyB.e-Radiator can cool the servers for freeC.e-Radiator can create cold air for free[答案]B[单选题]◆According to Jan Visser,the amount of heat produced by the e-Radiator_________.A.depends on the work being processed by PCB.can not be used as the home’s heating systemC.can not be used as the main source of heat[答案]C[单选题]◆The best title for this passage would be“_________”.A.The New Way to Heat HomesB.The New Way to Cool HomesC.Hot Computers Could Be Used for Free[答案]AWHY BUILD A SPACE ELEVATOR?The space elevator will reduce the cost of getting from Earth to space.It will also allow us to take very large payloads into space very easily,very safely.Because of that,we can build cities on the moon.We can build space stations.We can build large solar arrays in space to collect energy from the sun and beam it down to Earth.WHY NOT JUST USE ROCKETS INSTEAD?Rockets are very expensive.The shuttle costs S10,000a pound to put a payload into low-Earth orbit,and if you want to go to the moon or Mars,it’s hundreds of thousands of dollars per pound or more.Rockets are also very limited in the amount of payload they can carry.and they’re risky.With a space elevator,the cost is a fraction of that-it may go down to100th or1,000th of current costs-and there are no rocket engines that might explode.WHAT WOULD IT BE LIKE TO RIDE THE ELEVATOR?You’d go to an ocean platform,you’d climb into a module,and you’d feel it start moving.You’d see the Earth fall away.In just a half hour or so,you’d pass up through the clouds,and you’d start to see the curve of the horizon.Another half an hour to an hour later,you’d basically be in space.You’d see stars,even in the middle of the day.Eventually you’d be weightless.It’d be a very smooth ride:there wouldn’t be any shaking.ARE THERE POTENTIAL DRAWBACKS TO OPENING SPACE THIS WAY?Everything we do has the potential for creating some bad.If we mine an asteroid,the asteroid’s going to look ugly.just like a mine here.But I think the benefits of opening up space far outweigh the damage that we can see-benefits in terms of gaining energy from space to replace oil.additional capabilities in telecommunications. manufacturing in space.additional real estate and exploration.特别提醒：本题共5个小题,需要拉动答题框右边的滚动条使5个试题显示出来做答！！[单选题]◆If a space elevator is built,what can’t be built by us?A.Cities on the moon.B.Space stations.C.Skyscrapers in space.D.Expressways in space.[答案]C[单选题]◆The main reason of building a space elevator instead of using rockets is that________.A.the technology needed in building a space elevator is easier than that of rocketsB.the safety of a space elevator is better than that of rocketsC.the cost of building a space elevator is a fraction of using rocketsD.a space elevator is much more expensive than a rocket[答案]C[单选题]◆Which of the following statements is NOT correct,when you are riding the space elevator?A.You’d feel the Earth fall away.B.You’d see the horizon in just half an hour.C.You can’t see the stars in the middle of the day.D.You’d be weightless.[答案]C[单选题]◆What does the word“outweigh”in Paragraph4mean?A.Be less important than.B.Be greater than.C.Be lighter than.D.Be less valuable than[答案]B[单选题]◆Which of the following can summarize the main idea of this passage?A.Why do we need to build a space elevator?B.What can we do after building the space elevator?C.Why does building a space elevator cost less than using rockets?D.How can we build a space elevator?[答案]AWould a robot serving you coffee in bed make waking up easier on weekday mornings?Could a household robot help an elderly relative who is living alone?How would you like to climb into a robotic car and eat breakfast with the kids while you’re all driven to school and work?These scenarios may sound like science fiction,but experts say they’re a lot closer to becoming reality than you probably think.Brown University roboticist Chad Jenkins expects a near-term robot revolution that will echo the computing revolution of recent decades.And he says it will be driven by enabling robots to learn more like humans do-by watching others demonstrate behaviors and by asking questions.。

211262197_HAZOP_方法在氢气压缩机风险分析中的应用

第52卷第5期辽宁化工 Vol.52，No. 5 2023年5月 Liaoning Chemical Industry May，2023基金项目：中国石化炼油事业部项目（项目编号：CLY21027）。

收稿日期： 2022-06-06HAZOP 方法在氢气压缩机风险分析中的应用王一昊1,2，张毅1,2，凌晓东1,2，姜雪1,2（1. 中石化安全工程研究院有限公司，化学品安全控制国家重点实验室，山东青岛 266071；2. 中石化国家石化项目风险评估技术中心有限公司，山东青岛 266071）摘要：相比于传统的化石能源，氢能具有零排放、高热值等一系列优势，因此世界各国都相继加快了对氢能的研发和应用步伐。

氢气压缩机是我国加氢站建设的关键，也是确保加氢、储氢、运氢环节畅通无阻的关键设备。

由于氢气易燃易爆的特性，一旦氢气压缩机发生故障，极有可能会出现压缩机停机、气体泄漏等危险，甚至引发火灾和爆炸。

因此迫切需要对氢气压缩机可能面临的安全风险进行评估，辨识氢气压缩机运行中的危险因素，查明可能的故障原因并制定相应的保护措施。

以氢气压缩机为研究对象，采用HAZOP 方法对氢气压缩机进行了危险辨识与后果评估，保障了其安全平稳运行。

结果表明：氢气压缩机面临入口过滤器压差过高、一级进气缓冲罐压力过低以及一级排气温度过高等风险，应考虑增设报警装置。

关键词：氢气压缩机；自动化安全控制；HAZOP中图分类号：TQ086 文献标识码： A 文章编号： 1004-0935（2023）05-0669-04在大规模的气体化工过程中，压缩机的应用十分普遍。

在氢能网络的建设中，需要将氢气压缩至高压状态，以便用于存储、运输环节以及氢燃料电池汽车。

氢气压缩机通常会面临频繁的启动停机过程，进排气压力的波动范围大，维护频率低，维护难度大。

因此需要明确氢气压缩机可能面临的风险状况与风险等级，提前制定维护措施与风险预防措施，提高其安全平稳运行能力。

应用物理学专业拔尖人才培养方案的研究与实践——以哈尔滨理工大学应用物理学专业为例

———以哈尔滨理工大学应用物理学专业为例
高玮，朱智涵，姬广举
（哈尔滨理工大学，黑龙江哈尔滨 150080）
摘要：为响应教育部倡导的基础学科拔尖人才培养计划（珠峰计划），哈尔滨理工大学依托理学院物理系实施强
基计划，成立应用物理学专业“王大珩精英实验班”。文章从培养目标、毕业要求、课程体系和科研创新能力培养
实验方法和技能；掌握资料查询、文献检索及运用现代信息技术获取最新参考文献的基本方法；了解物理学的理论前沿、应用前景和最新发展动态；具备运用物理学的研究方法进行科学研究、技术创新的工作能力；具有针对特定科学问题设计解决方案，归纳、整理、分析数据，撰写论文，参与学术交流的能力；掌握一门外语，能熟练阅读本专业外文文献资料，可进行跨文化环境的交流。
二、课程体系基本框架本专业课程体系内容完全涵盖了专业规范所要求的专业基本知识体系（7 个专业基础知识领域，23 个核心知识单元），结合拔尖人才的特点与要求，经过对培养目标的分析与论证，充分考虑了课程对毕业要求的支撑，形成了本课程体系。课程设置主要包括：自然科学类课程、人文社科经管类课程、专业基础类课程、科研基础与实训类课程、专业模块选修类课程，以及一般实践类课程。本方案的课程设置情况具体如下。课程数量：通识课 23 门，专业核心课 14 门，专业选修课 8 门，实践环节 13 门，共计 58 门。学分情况：通识课 75.5 学分，专业核心课 46 学分，专业选修课 15.5 学分，实践环节 38 学分，共计 175 学分。学时情况：通识课 1 270 学时，专业核心课 744 学时，专业选修课 310 学时，共计 2 324 学时。三、专业课程设置与特色为了突出大珩班“厚基础、重实践、强创新”的专业特色，物理专业基础课占较大比重，普通物理类和理论

2-1 中文期刊全文数据库

• 学术文献搜索：对文献内容的详细标引
• 定义搜索：可对学术定义进行快速查询 • 翻译助手：实现中英文词、短语、句子的辅助互译
• 学术趋势：提供学术趋势分析服务
• 图片搜索：提供各行业图片数据 • 数字搜索：提供数字知识和统计数据搜索服务 • 工具书：查找各个学科的1000多万个词条
几个常见问题 1、关于“用户数已满”的问题
• 比较 – 收录年限：CNKI、VIP在时间跨度、收录期刊种类、文献量上有优势，适于回溯性检索，但VIP收录期刊的年限及连续性不及CNKI；万方收录年限短，但收录全面，却实效性较强，适合于新课题检索。 – 分类检索：CNKI提供多种分类检索途径，VIP采用中图分类法，分类层次较深入；万方采用期刊分类导航，不能直接从分类角度检索文献，提供的期刊名称导航，服务历史较长，近年连续性较好 – 主题检索：CNKI可检索字段较多、检索结果包括同类文献、相关研究机构、相关文献作者链接，对扩展检索结果可以起到启发作用； – 检索效果：在相同检索条件（检索入口、检索限定）下，三者的检索效果依次为：CNKI、万方、VIP，原因是：收录合著者、语种、收刊范围上不同，例如，VIP虽然数量大，但连续性较差 – 浏览器：都支持PDF，CNKI还支持CAJ – 用户权限：CNKI的并发用户数限制
时间：2003-2009，范围：核心期刊，检索结果245篇
如果输入方式改变，检出结果大不一样，ห้องสมุดไป่ตู้析问题出在哪里？
如果检索字段是“主题”而不是“篇名”，检出结果又如何？
• 检出1184篇
构建检索式例三（专业检索） • 在中国学术期刊全文数据库中查找我校李根生老师发表的文章。 • 检索项：作者=李根生 AND 单位=石油大学，共检出22 条记录。

开源信息检索技术在高校图书馆的应用——以昆明理工大学图书馆为例

开源信息检索技术在高校图书馆的应用
以昆明理工大学图书馆为例
孔云杨婷
（明理工大学图书馆，云南昆明６０９）昆５０３
摘
要：本文以昆明理工大学图书馆为例，从高校图书馆的角度，通过对开源技术的特点及其功能分析，探讨了开源检
储引擎插件。Ｓｈｎｐｉｘ的特性：高速索引（在新款ＣＵ上，Ｐ近１ＭＢ秒）０／；高速搜索（—Ｇ的文本量中平均查询速度不到０１２４．秒）；高可用性（ＣＵ上最大可支持１０Ｂ的文本，０文单Ｐ０Ｇ１Ｍ０档）；良好的相关性排名，提供支持分布式搜索；提供文档摘要生成；ＭｙＱＬ内部的插件式存储引擎上搜索，提供Ｓ支持布尔
索技术在高校图书馆的发展与应用问题，为我国其他高校图书馆提供经验借鉴。关键词：开源软件；高校图书馆；信息检索；云计算；ｗｅ．ｂ２０中图分类号：６５２文献标识３：Ａ５－文章编号：１７ — ２９（０）０ — ０９０６３２１２１１８０５－４
１Ｗｅ２０时代对图书馆发展的新要求．２ｂ．
数据、息、知识的爆炸性增长给图书馆带来了戏剧性信
的挑战，但也为其发展提供了前所未有的机遇。数字图书馆的发展是对传统图书馆的颠覆，是未来图书馆生存的必然，其发展的核心问题是如何更好地对搜集、织、检索与利用组好信息资源。许多读者在面对海量信息时显得手脚无措，读者对图书馆的服务提出了更高的要求，希望能快速准确地获

谈连续刚构桥控制长期下挠的措施

谈连续刚构桥控制长期下挠的措施
郭永平
（广东华路交通科技有限公司，东广州广５０５１５０）
摘
要：结合多年的工程实践经验，出通过跨中对顶合龙张拉下缘预应力索进行体系转换、提通过体外索和跨中预压重等措施控
制连续刚构桥长期下挠，解决了控制大跨梁桥长期下挠的难题，保证了结构的安全。关键词：续刚构桥，连长期下挠，中对顶合龙，跨体外预应力索
体外预应力索从而减小桥梁运营后的徐变下挠量也是一种行之
有效的措施。下述为几例设置体外预应力索的工程实践。
１１８）９６年广东九江大桥成功研制研平行钢丝热挤ＰＥ索套。当时在２×１０ｍ独塔斜拉桥和７×５６０ｍ顶推连续梁桥中使用体外索，取得了良好的效果。２２）０世纪９０年代初，在福建省节
见图３。在苏通大桥辅航道桥预应力的设计中，了减小运营后为
的徐变下挠量，在跨中位置除了预留３对３１．４体内预应力１５２外，还设计３对２１．４体外备用钢束。这是典型的体内、５５２体外
预应力钢索混合布置的方式。
ｂ随着时间的推移，）梁徐变下挠，
产生。本文通过对多年工程实践的总结，出了控制大跨梁桥长部分的恒载对结构产生的弯矩予以消除。提期下挠可以采用的新的思路：在桥梁恒载形成的各种工况中， “ 分
阶段设置预应力来抵消恒载弯矩 ” 。当箱梁各个截面所存在的恒载弯矩都不大时，么箱梁下挠就得到有效的控制。其主要实施那

2024感恩节活动策划模板六篇

2024感恩节活动策划模板六篇感恩节活动策划篇1一、活动背景。

每年的十一月的第四个星期四是西方传统节日--感恩节。

虽然是外国节日，但是拥有一颗感恩的心却是每一个人都应该的。

尤其是当代大学生多半是独生子女，凡事都先想着自己，对父母都很少关心，对一些曾经帮助过自己的人难以言表谢意。

所以开展此活动唤起人们的感恩之心，让同学们将自己的真实感情表达出来。

二、活动目的。

唤起人们的感恩之心，在心中培植一种感恩的情感，无论对待父母或者是老师，朋友或者对手，快乐或者悲伤，都能以一颗感恩的`心去面对。

三、活动时间。

11月22日。

四、活动地点。

重庆理工大学一食堂广场。

五、活动对象。

重庆理工大学全体同学。

六、活动方式。

帮助有需要的同学赠送感恩卡片。

七、活动内容。

一、前期安排。

1．根据协会统一的安排和部署策划部提前起草活动策划,由部长审核。

2．外联部尽可能拉到赞助，并提前两天将需要的卡片买好。

3．办公室准备好会旗和宣传横幅，并在活动前一天申请到场地。

4．办公室打印两份青协成员联系表。

5．宣传部提前两天画好活动海报，并准备好活动所需的宣传单。

6．活动前一天办公室开短会，确定人员分配和通知相关事宜。

7．外联部提前一天在一食堂和二食堂周围发传单，并且悬挂好横幅。

二、活动流程。

1．09：40以前办公室人员把桌子抬到一食堂广场，并且借到帐篷。

2．09：40左右新闻部组织成员到一食堂广场配合办公室布臵好场地。

3．10:00至19:00青协相应成员按照安排表在一食堂广场负责对需要送卡片的同学进行登记。

4．活动期间外联部负责好横幅以及宣传标语的维护。

5．在相应活动时间内每组组长不定时在一食堂附近对组员进行巡查和监督。

6．活动期间青协没有重要事情的成员尽量到一食堂帮忙。

7．活动期间新闻部在各个时间段到一食堂广场进行摄影和拍照。

8．19:00后，由办公室将相关宣传横幅和标语收好以及将借来的桌子和帐篷归还到相应地点。

9．晚上21:00由会长组织20人左右在菊轩大厅集合，再统一安排派送卡片。

理工文献检索期末试卷

一、单项选择题（从下列各题四个备选答案中选出一个正确答案，并将其代号写在答题纸相应位置处。

每题2分，共30分）1．_C_ 是题录型检索工具A. CABIB.中国学术期刊文摘C.全国报刊索引（自然版）D.经济纵横2. 浏览超星数字图书馆，应首先安装__D_____.A. Apabi ReaderB. Adobe ReaderC. CAJ ViewerD. SSReader3. 世界上第一大联机检索系统是_A_。

A.DIALOG系统B.OBRIT系统C.OCLC系统D.STN 系统4. 利用baidu搜索信息时，要将检索范围限制在网页标题中，应该使用的语法是___B_______。

A.site:B.intitle:C. inurl::5．国际农业和生物科学中心英文名称的简称为_A 。

A.CABIB. AGRINDEXC. BAD.B of A6.信息检索根据检索对象不同，一般分为___C___________。

A. 二次检索、高级检索B.分类检索、主题检索C.数据检索、事实检索、文献检索D.计算机检索、手工检索7. 国际上评价期刊最有影响力的一个指标是___A_____。

A. 影响因子B.读者统计数据C.引文量D.价格8. 二次检索指的是：___C__________。

A．第二次检索B．检索了一次之后，结果不满意，再检索一次C．在检索结果中运用“与、或、非”进行再限制检索D.以上都不是9.国际连续出版物编号___A__________。

A.ISSNB.OCLCC.ISBND. CSSCI10．下列搜索引擎具有书名号检索功能的有______B________。

A．Google B.百度C.中搜D.AltaVista11．《中文核心期刊要目总览》2004 版的“农业经济”类核心期刊有_B__ 种。

A．20 B．19 C．17 D．1512．通过追溯检索获得的相关文献与原文献相比在发表时间上__B__。

A．早B.晚C. 相同D. 不确定13．在维普中文期刊全文数据库中“在检索结果中”检索相当于B 。

基于CTTI数据的我国高校智库发展特点分析

构,形成政、商、学三大教学体系，拥有“中国经济观
察报告会”“格政”“国家发展论坛”3个智库品牌活
动,牵头组织“中美经济对话”和“中美卫生对话”，
大学建
一流大学中发了
作用⑷*
成立于1985年的复旦大学美国研究中心作为教育部人文社会科学重点研究基地，是针对美国问
题研究以及中美关系研究的国家级研究单位*该
研究中心由已故复旦大学校长谢希德教授创建，具
有学术研究、政策咨询、人才培养、国际交流四大功
能,现已培养美国研究和中美关系研究方向硕士、博士研究生数百人，主办《美国问题研究》辑刊
（CSSCI），出版《21世纪的美国与世界》丛书，在中美外交领域为国家提供重要的决策咨询服务[5] *
广西大学中国一东盟研究院立足于广西壮族
TTCSP（美国宾夕法尼亚大学“智库研究项目”"《全球智库报告2019》显示，中国多家大学智库入选不同专业榜单*其中北京大学国际战略研
—66—
北京财贸职业学院学报
究所、清华-卡内基全球政策中心等6家中国高校头部智库上榜TTCSP “2019全球最佳大学附属智库”榜单（排名情况如表2所示）*另外如中国人民大学重阳金融研究院（RDCY）入选“2019全球最佳国内经济政策研究”榜单（61位）及“2019全球最佳外交政策与国际事务研究”榜单（113位），该智库关于中美人文交流和“一带一路”倡议的两份研究报告还入选“2019全球最佳智库政策研究报告”；清华大学卡内国际研究中心、师大学洲研究院（IASZNU）入选“全球最佳区域研究中心（大学附属）”榜单（分列第3位、第25位）*浙江师范大学非洲研究院是我国高校首家成立的综合性非洲研究院，以其专业性非洲研究已连续四次上榜*云南大学亚洲国际河流中心是我国目前唯一专注于国际河流问题的研究机构，据相关介绍，该中心对我国13条主要国际河流、全球15条国际河流及资源环境开展研究,专业特色鲜明[3] *

回填反压法处治滑坡设计

第2期(总第269期）山西交通科技No .22021 年 4 月SHANXI SCIENCE & TECHNOLOGY of COMMUNICATIONSApr .回填反压法处治滑坡设计卫亚辉(山西省交通规划勘察设计院有限公司，山西太原030032)摘要：以某高速公路施工过程中边坡滑坡处治设计为例，分析该段滑坡成因，并对其进行边坡稳定性计算，研究回填反压法在工程实际中的应用效果，后续施工结果表明处治效果良好，可为类似工程提供一定的借鉴。

关键词：高速公路;路基边坡；滑坡处治中图分类号:U 418.55 文献标识码:A文章编号：1006-3528(2021 )02-005(M )31工程概况某高速公路K 12+100—K 12+280段路基于2019 年5月14日开始强夯施工，路基从2019年5月24日开始填筑，2019年6月26日路基填筑高度为7 ~ 8 m ,发现已填筑的路基边坡以及路基填方坡脚位置有多条不规则裂缝，坡脚位置有3条沟天然形成土包(开挖出土质为粉土及粉质黏土），土包原地貌也存在不规则裂缝。

开始由一条裂缝，裂缝宽度为2 ~ 3 cm ,经过 10 d 左右时间观察，出现多条不规则裂缝，裂缝宽度为4 ~ 5 cm ,后续裂缝宽度随时间持续增长，增长速度相对比较慢，此处的裂缝对填方路基主体存在滑坡及坍塌的安全隐患。

图1边坡裂缝分布位置图2工程地质条件2.1地形地貌本段边坡属于剥蚀堆积黄土丘陵区，微地貌为黄土冲沟，呈鸡爪状，本项目产生裂缝的边坡以填方边坡形式通过。

2.2地层岩性地层岩性主要为耕植土、第四纪上更新统(仏™1) 粉土等，上第三纪上新统(N /)洪积粉质黏土、粉土、钙质结核，二叠纪石千峰组(P /)强-中风化泥质砂岩夹泥岩与泥岩互层，现分述如下：a )Q 产粉土黄褐色，稍湿，稍密，稍有光泽，稍有韧性，刀切面粗糙，干强度差，局部夹粉质黏土，局部含有钙质结核。

重症监护病房患者院内获得压力性损伤的危险因素分析

护理学杂志2021年2月第36卷第3期•53 ••基础护理•重症监护病房患者院内获得压力性损伤的危险因素分析庄秋楓1，肖世极2，周秀花1，李映林2Pressure injury risk factors i n critical care patients Zhuang Qiufeng , Xiao Shiji , Zhou Xiuhua , Li Yinglin摘要：目的研究重症监护室患者院内获得压力性损伤的临床特征以及危险因素，为针对性干预提供参考。

方法通过病例对照研究，利用美国波士顿B I D医疗中心重症监护病房建立的重症医学数据库，分析重症监护病房患者2级以上获得性压力性损伤发生危险因素。

结果共30171例纳入分析，1667例发生2级以上压力性损伤，46. 8%为70岁以上老年患者，73. 4%的患者于入院后1周内出现压力性损伤。

44. 4%压力性损伤发生部位在骶尾部。

Logistic回归分析得出急性生理学评分，Braden评分中的摩擦力与剪切力、移动能力、营养摄取能力，血红蛋白、血管升压药物、镇静药物、机械通气、脓毒血症、类风湿性关节炎、糖尿病、肾衰竭、瘫痪、体质量减轻、肥胖为压力性损伤发生的危险因素（P<0. 05, P<0. 01)。

结论重症监护室患者获得压力性损伤发生率较高，影响因素多，需进一步细化研究；同时医护人员应进行个性化评估及预防。

关键词：压力性损伤；危险因素；重症监护病房；病例对照研究；危险评估中图分类号：R473. 2 文献标识码：B 犇犗犐 10. 3870/j. issn. 10014152. 2021. 03. 053压力性损伤（Pressure Injury,PI)是长期卧床患者的常见并发症，可增加感染概率，降低生活质量，增加医疗费用及病死率，IC U患者压力性损伤发生率 16. 9%〜23. 8%[1]，在临床所有科室中最高。

压力性损伤的发生是多因素综合作用的结果，了解压力性损伤发生的高危患者，是预防压力性损伤的基本步骤。

5 喇叭系统检测维修

情感
目标
1.体会学生团队协作的重要性；
2.能够规范操作，培养认真细致的精神，初步形成良好的职业素养。
重点
掌握喇叭故障的诊断流程。
难点
能进行教学车喇叭部件拆装。
教学方法
任务驱动法、分析法、指导法
学法指导
自主学习法、角色扮演法、仿真练习法、实践法
教学流程
一、课前准备，创设任务；二、视频导课，引出任务；三、结构学习，分析任务；
（2）检查喇叭继电器，用4493继电器拆卸工具拆卸继电器，用万用表检查继电器各脚之间的通断性，若有两队触点导通或无任何一对触点导通，说明继电器损坏，找到导通的一对触点，这就是继电器线圈接头，用3587含组合插头的连接线组将线圈接头按照电路图分别接蓄电池正负极，应该能听到继电器的响声，保持通电，用万用表测量继电器另一对接脚的导通性，若导通说明继电器正常，若不通更换继电器。确认继电器无故障后，验证喇叭故障是否排除，若没有排除进入下一步的检查。
福建理工学校教案活页
课程名称：汽车电子电气与空调舒适系统技术NO：5
课题
喇叭系统检测维修
执行时间
班级
18汽4
18汽4
周次
课时
8课时
节次
3.4
1-6
日期
7.6
7.7
教学目标
知识
目标
1.掌握喇叭故障的诊断策略。
2.掌握喇叭故障的诊断流程。
技能(方法)目标
1.熟悉万用表的使用，熟练测量电压、电阻、电流。
2.常用维修工具使用熟练，能进行教学车喇叭部件拆装。
（4）拆卸方向盘上的喇叭开关，断开喇叭开关接头，用3587连接线组将喇叭开关插头直接接地，喇叭工作，更换或维修喇叭开关。喇叭开关接地后喇叭仍然无声，用3587连接线组一端连接蓄电池正极，另一端连接喇叭接头，喇叭无声更换喇叭。若喇叭工作，进一步检查喇叭导线，必要时更换配电中心。