初中数学教法初探

“教师主导与学生主体相结合原则”在这里就可以展现得淋漓尽致.良好的开端是成功的一半,课堂导入是课堂教学的起步阶段.教师授课导入得好,不仅能吸引住学生,唤起学生的求知欲望,而且能燃起学生智慧的火花,使学生积极思维,勇于探索,主动地去学习,从而巩固原有知识,传授新的知识,使教学达到预期的效果.因此,在课堂教学中,一定重视教学伊始的导入艺术和方法.正确的新课引导要做的也就是做到真正的即能“启”而且还能“发”,以求创建和谐的教学情景,以激发学生学习新知向知识的海洋进军的欲望.     

云南个旧陡岩勘查区Sn多金属矿化信息提取与评价

个旧矿区被南北向个旧断裂分为东、西2个矿区。东区是已知矿床的集中区,随着东区"危机矿山"问题的日益凸显,西区的地质研究工作和资源潜力评价已成为矿山深部和外围找矿的热点。西区陡岩地区具有良好的成矿地质条件,是近年来个旧西区地质找矿工作的重点。采用因子分析(FA)-多重分形法(S-A)对1∶1万原生岩石化探数据中17种元素进行分析,获取锡多金属矿致异常信息,再通过变差函数分析异常控制因素,结合本次1∶1万野外地质填图成果,获得如下认识:①F1因子代表Cd-Hg-Pb-Zn元素组合,是中低温热液型多金属矿化的反应;F3代表Sn、Mo元素组合,反映的是岩体及热液的相关信息;F5包括Sn、Sr,Sr是碳酸盐岩的常见元素,反映Sn元素部分来源于个旧组灰岩和法郎组炭质、泥质灰岩。②勘查区东南部异常晕展布特征为串珠状分布且异常浓集中心恰好都位于岩性分段面,推测该区存在隐伏岩体。③该区的断裂控矿性不明显,Sn元素异常展布的空间结构性主要由南西向的地层和该区的隐伏岩体控制。     

Effect of Media on the in vitro Degradation of Biodegradable Ureteral Stent

The biodegradable ureteral stent should retain their supporting properties for defined period and then gradually degrade to small particles with the flow of urine. The mechanism and process of the stent’s degradation should be investigated and understood well due to its direct impact on the stents’ usage. An enhanced braidbased degradable ureteral stent composed of poly-glycolic acid(PGA) and the copolymer of lactic and glycolic acid(PGLA) was evaluated in vitro in this study with four kinds of degradable media:human urine(HU,pH = 7. 4),artificial urine(AU,pH = 5. 8),and phosphate buffer solutions( PBS,pH = 5. 8 and 7. 4) so as to compare the effects of media on the degradation of stents. The mechanical properties and morphology were observed at different degradaing time intervals of 0,7,14,21,28,and 35 d. The in vitro degradation behaviors of stents in four kinds of media were extremely different. The degradation rate of stents in HU was the highest. The impact of media’s pH to the degradation is not obvious while the components in the media contribute much to the difference.     

正确理解与运用同义的单双音节词语

本对现代汉语中“同义的单双音节词语”进行了分析研究，对少数民族学生学习汉语应注意的问题作了阐述。     

强化国家战略科技力量支撑，服务构建新发展格局

 加快构建以国内大循环为主体、国内国际双循环相互促进的新发展格局,是事关中国高质量发展的重大战略任务。支撑服务构建新发展格局是国家战略科技力量的责任担当。通过认识强化国家战略科技力量支撑服务构建新发展格局的重大意义,从统筹发展与安全的视角,提出了强化国家战略科技力量支撑服务构建新发展格局的总体思路和基本原则;从安全、发展、开放3个层面,提出了强化国家战略科技力量支撑服务构建新发展格局的主要路径：强化建制化、体系化支撑保障,夯实新发展格局安全基础;增强原创引领带动作用,提升双循环体系的动能与效能;面向国家重大区域发展战略,提升新发展格局的开放水平。     

合肥市沿河路桁架拱公路桥设计和施工

合肥市沿河路桁架拱公路桥设计和施工钱让清，祖朝兴（安徽大学交通分校合肥２３００５１）（合肥市政公司一处合肥２３０００１）合肥市沿河路桁架供公路大桥为合肥市建成的第一座桁架拱桥，由合肥市政公司一处以总价９８万元中标承建，实际耗资７９．８万元，盈利１８．...     

国家自然科学基金为留学回国人员提供施展才智的条件

1986年国家自然科学基金委员会(NSFC)成立,1987年开始设立青年科学基金。几年来,得到NSFC项目资助的留学回国人员共有近千人。这批留学回国人员利用科学基金资助的有限经费,得以继续开展以至开拓在国外所从事的研究工作。有些人的科研活动还不断深化,有所创新。有的已经纳入国家的攻关计划和高技术研究计划。这些留学回国人员已成了本系统、本单位的科研骨干。有些人还担任了重要部门的科技领导。几年     

Properties of Scaffold Reinforcement for Tendon Tissue Engineering in vitro Degradation

Four kinds of braided yarns were produced with different proportions of polyglycolic acid( PGA) and polylactic acid( PLA)multifilaments( 2PGA /1PLA, 2PGA /2PLA, 3PGA /1PLA, and3PGA /2PLA). A novel artificial plain stitch scaffold reinforcement was manufactured by braiding technology and knitting technology respectively. Tendon scaffold reinforcements were investigated for 8weeks in phosphate buffered solution( PBS)( pH = 7. 4) at 37 ℃.The degradation was studied with regard to the mass loss,tensile properties,grams per square meter( g /m2),thickness,caliber,and porosity of scaffold reinforcements. The experimental showed that during the process of 8-week degradation,the mass losses of scaffold reinforcements were small in the first 3-week,but they increased rapidly after 3-week,and the speeds tended to be small gradually after 6-week; the tensile properties dropped rapidly in the first 2-week; the grams per square meter and thicknesses speeded down obviously between 3-week to 6-week. The caliber and porosity of scaffold reinforcements first decreased and then increased gradually. The porosity can reach more than 97%.     

隙积术和会圆术——沈括《梦溪笔谈》评注一则

[说明]沈括(公元1031——1095年),字存中,钱塘(今浙江省杭州市)人。他不仅是我国北宋时期著名的科学家,而且是一个积极参加王安石变法运动的进步政治家,是一个法家。王安石变法期间,沈括担任了三司使(主管财政经济)等职,积极参与了新法的制订和实施,“朝廷新政规画,巨细括莫不预”(李焘《续资治通鉴长编》卷283)。沈括一生的科学实践是同当时的政治斗争紧密联系在一起的,是积极为推行新法服务的,如王安石农田水利法的重点项目汴河疏浚工程,就由沈括负责调查规划,他的测量成果,对汴河疏浚工程的设计和施工起了重要作用。     

石墨球生长的热力学及动力学稳定性探讨

自球铁问世以来,人们做了大量的试验研究和理论分析,努力探讨石墨球化机理,出现了许多解释球化现象的学说。尽管对球化机理至今尚未形成统一认识,但有几个方面的研究结论已为人们普遍接受:一是球内部石墨基面(0001)平行于圆围按年轮