共查询到20条相似文献，搜索用时 265 毫秒
1.
2.
语言是文化的组成部分,一种语言代表了一种文化,同时语言也是思维的工具,它帮助人们认识丰富多彩的世界。因此,学习一种语言就是学习一种文化;保存一种语言就是保存一种文化。相反,失去了一种语言不仅意味着失去了一种文化,失去了一种思维方式,失去了一份宝贵的历史文化遗产,而且意味着我们人类失去了一种可供比较、借鉴的文化和信息来源。对广西仡佬语濒危成因进行分析,不仅能起到加强对仡佬语的保护作用,而且能使仡佬语所蕴含的文化得到保护和传承。 相似文献
3.
根据2001~2003 年调查,入侵山东的外来有害生物有 104 种,其中,有害病原微生物 12 种,有害植物 65 种,有害动物 27 种.现已有 3 种病原微生物、1种有害植物和3种有害动物被消灭.对现入侵山东的97种外来有害生物的地理分布作了调查,并分析了其地理分布特点,为外来有害生物的预测预报、检疫、综合治理、系统控制提供了科学依据. 相似文献
4.
5.
常熟地区蝶类资源调查初报 总被引：1，自引：0，他引：1
常熟地区蝶类现记录到52种,隶属6科,其中凤蝶科9种,粉蝶科7种,眼蝶科4种,灰蝶科8种,弄蝶科6种,蛱蝶科18种。对蝶类资源进行了初步的论述,提出了一些保护对策。 相似文献
6.
沂蒙山区野生蔬菜资源及其开发利用初探 总被引：4，自引：0，他引：4
初步记述了沂蒙山区的野菜资源,共有41科,100属,129种.其中草本植物115种,木本植物7种,藻菌植物4种,蕨类植物3种.对该区野生菜的开发和利用现状进行了评述,并提出了一些措施 相似文献
7.
经调查,笔架山公园记录鸟类81种,隶属12目、31科、58属。其中留鸟47种、候鸟30种(冬候鸟23种、S候鸟7种)、旅鸟4种,国家重点保护鸟类6种。东洋界的鸟41种,古北界的20种,埃塞俄比亚界的1种(引进种),古北界和东洋界广泛分布的鸟类19种。在54种当地繁殖鸟类中,东洋界37种。笔架山公园的鸟类组成,东洋种具有显著的优势,并显示闽广沿海亚区的区系特征。文章分析了笔架山不同环境和植被类型分布的不同鸟类生态类群的种类组成和数量特点,评价了鸟类资源的状况,提出了若干保护管理建议。 相似文献
8.
"四种能力"的培养是高校人才培养的本质要求和最终目标。对"四种能力"的内涵做了界定,阐述了"四种能力"间的相互关系,在此基础上,分析了基于"四种能力"培养的教学管理要素,初步构建了基于"四种能力"培养的教学管理机制。 相似文献
9.
10.
田慧敏 《赤峰学院学报(自然科学版)》2014,(11):7-9
本文对采自白音敖包自然保护区,达里湖南岸、黄岗梁国家森林公园等地的大型真菌标本300余份进行鉴定,共计103种,20科46属,其中子囊菌2种,担子菌101种,内蒙古新记录种有6种.内蒙古特有种5种,食用菌42种,药用菌40种,毒菌16种.文中对新纪录种进行了简单描述并对部分种进行了简要讨论. 相似文献
11.
A combined cycle fatigue （CCF） testing system with ultrasonic frequency component was developed toevaluate the CCF properties of S350 steel welded joints in this study. The fatigue testing results indicated that the S-Ncurves of CCF did not have fatigue limit, which agreed with those of pure high frequency fatigue of welded joints. TheS-N curves showed that the CCF strength of welded joints dropped greatly with the increasing interaction between highand low frequency fatigue loading. An approximation design method of CCF was presented using amplitude envelopeas the stress range. 相似文献
12.
Improving the Fatigue Performance of the Welded Joints of Ultra-Fine Grain Steel by Ultrasonic Peening 总被引：2，自引：0，他引：2
Contrast tests were carried out to study the fatigue performance of the butt joints treated by ultrasonic peening, aiming at the improvement of ultrasonic peening treatment(UPT) on welded joints of a new material. The material is a new generation of fine grain and high purity SS400 steel that has the same ingredients as the traditional low carbon steel. The specimens are in two different states:welded and ultrasonic peening conditions. The corresponding fatigue testing data were analyzed according to the regulation of the statistical method for fatigue life of the welded joints established by International Institute of Welding(IIW). Welding residual stress was considered in two different ways: the constant stress ratio R = 0.5 and the Ohta method. The nominalstress-number (σ-N) curves were corrected because of the different plate thickness compared to the standard and because there was no mismatch or angular deformation. The results indicated that: 1 ) Compared with the welded specimens, when the stress range was 200 MPa, the fatigue life of the SS400 steel specimens treated by ultrasonic peening is prolonged by over 58 times, and the fatigue strength FAT corresponding to 106 cycles is increased by about 66％; 2) As for the SS400 butt joint ( single side welding double sides molding) , after being treated by UPT, the nominal S-N curve (m = 10) of FAT 100 MPa(R =0.5) should be used for fatigue design. The standard S-N curves of FAT 100 MPa (R = 0.5, m = 10) could be used for fatigue design of the SS400 steel butt joints treated by ultrasonic peening. 相似文献
13.
本文以大型焊接回转筒体工作状态中的主要技术参数为依据,分析和判断大型焊接回转筒体环缝接头产生疲劳失效的部位和原因。通过计算分析,校核和建立故障树分析方法,求出大型焊接回转筒体的失效模式。从而,提出预防失效的主要途径,为大型异厚回转筒体的设计、制造、使用提供可借鉴的依据。 相似文献
14.
Brittle cracks were observed in the welded beam-to-column connections of steel frames during an earthquake. The crack propagation and accumulated damage to the connections can lead to fractures at much lower ductility ratios. Understanding the connections’ damage behavior during an earthquake is crucial for the design of steel moment frames in seismic areas. Nine full scale beam-to-column connections were tested under constant amplitude and variable amplitude cyclic loading. The effects of loading amplitude, loading history, and peak load on the connection damage were analyzed. The damage characters were studied and three damage evolution models were calibrated and validated based on test results. The damage mechanism was investigated and an effective plastic strain index was developed to evaluate connection damage based on a ductile fracture mechanism. A fatigue fracture mechanics-based model, for evaluating the damage process of beam-to-column connections under cyclic loading, was proposed. 相似文献
15.
产品焊接试板是压力容器生产工艺控制的重要环节，产品质量是否可靠，焊接试板检测结果是主要的判据。本文分析了薄焊接试较弯曲试样失效的原因，并对减少失效的可能性作出了阐述。 相似文献
16.
17.
应力腐蚀断裂是焊接结构断裂失效的重要原因之一,这种断裂失效呈脆断特点,易导致灾难性后果.探讨应力腐蚀裂纹的产生、开裂的机理及其影响因素,并提出控制焊接结构发生应力腐蚀断裂的措施. 相似文献
18.
给出了焊接钢筋网单向板裂缝间距和宽度的计算公式，并作了7块单向板的试验来验证，结果表明，这些板的开裂间距主要依赖于焊接横向钢筋间距，而裂缝宽度的计算是根据裂缝间距进行的。 相似文献
19.
The mechanical characteristics of the weld joint were investigated by tensile test, microstructure test, and microhardness test. The welded tube NC bending tests were carried out to evaluate the weld on the formability of the QSTE340 welded tube. The results show that the wall thinning degree, cross-sectional deformation and springback angle increase significantly as the weld line is located on the outside of the bend compared with that located on the middle and inside, and the welded tubes produce nearly identical performance as the weld line is located on the middle and inside. The wall thickening degree decreases much as the weld line is located on the inside of the bend. So the welded tube can acquire good bending formability as the weld line is located in the region away from the outside of the bend. 相似文献
20.
张建 《温州职业技术学院学报》2014,(1):61-64
低温环境金属的焊接易导致焊接接头产生冷裂纹.为减少焊接冷裂纹的产生,需采用预热措施.采用焊条电弧焊在环境温度为-15℃下进行T形接头焊接仿真,运用Simufact-Welding软件分析焊件预热到80℃和120℃时焊缝处的残余变形和残余应力.结果表明,预热到120℃时,焊缝处的残余变形小;预热到120℃时,除焊缝起始点和终止点外,其余焊缝处的残余应力小.因此,合理控制预热温度,可减小晶粒脆化;适当增大t./5时间,有利于缓解接头的冷却速度,减小淬硬倾向. 相似文献