首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
From summer 1792 until spring 1797, Alexander von Humboldt was a mining official in the Franconian parts of Prussia. He visited mines, inspected smelting works, calculated budgets, wrote official reports, founded a mining school, performed technological experiments, and invented a miners’ lamp and respirator. At the same time he also participated in the Republic of Letters, corresponded with savants in all Europe, and was a member of the Leopoldine Carolinian Academy and the Berlin Gesellschaft Naturforschender Freunde. He collected minerals, made geognostic observations, performed chemical and physiological experiments, read the newest scientific journals, and prepared and published texts on mineralogy, geognosy, chemistry, botany and physiology. Humboldt did his scientific investigations alongside his administrative and technical work. This raises the question of whether there were fruitful interactions between Humboldt's technical-administrative work and (parts of) his natural inquiry. I argue that the mining official Humboldt was a late eighteenth-century figure of hybrid savant-technician. Mines and smelting works provided numerous opportunities for studies of nature. Humboldt systematically used inspection tours for mineralogical and geognostic observations. He transformed mines into chemical laboratories, and he transferred knowledge and material items from his natural inquiries in mines to academic institutions. The main objective of this paper is to illuminate the persona of savant-technician (or scientific-technological expert) along with Humboldt's mixed technological and scientific work during his term as mining official.  相似文献   

2.
The addition of 'fire' to the European battle repertoire resulted in the close-order drill for manoeuvres of the line. Begun in late sixteenth-century Netherlands and perfected in eighteenth-century Prussia under Frederick the Great, the drill's precision marching evolved into a military science which conceived what infantry acquired through rigorous training as a lawful 'second nature' of men. In contrast, the liberal Webers' 1836 locomotion research orientation was, as was that of French skirmishing, one of natural self-regulation. Later Prussian military science, restored in Imperial Germany, was merged into locomotion science.  相似文献   

3.
本文主要研究通过引入滑动窗口模型,提出了面向XML查询数据流的频繁查询子树在线挖掘算法。算法以全局Trie树为数据缓存结构管理和维护缓存池的数据流,采用自下而上、基于前缀等价类的遍历方式快速产生所有带根查询子树和标准查询子树。实验结果表明该算法具有挖掘速度快、内存消耗稳定等特点,可以有效、平稳地处理XML查询数据流。  相似文献   

4.
矿山环境问题一直受到国际社会的广泛关注和重视,为了实现资源开采与环境协调一致,实现”低开采、高效率、低排放”目的。本文介绍了矿山开采和利用过程中的矿山环境问题,以及所引起的各种地质灾害现象。分析了资源开采与环境保护之间相互关系以及矿区可持续发展的重要性。针对典型矿山环境破坏问题提出了治理措施,提出了符合21世纪资源开发的全局性矿区”绿色开采”模式。  相似文献   

5.
考虑BP网络存在收敛速度慢、局部极值等缺点,引入线性下降惯性权重粒子群优化(LWPSO)算法,建立基于线性下降惯性权重粒子群优化(LWPSO)算法的人工神经网络模型,在分析抚顺发电有限责任公司厂区地表下沉的实际观测资料的基础上,对厂区的任意点,任意时刻进沉陷预测研究。  相似文献   

6.
为了确定大安山矿+680m水平9槽近距离薄煤层回采巷道合理的布置方式及护巷方式,根据理论分析和数值模拟,确定了单一煤层开采的开采方案,提出了9槽回采巷道留3~5m窄小煤柱护巷的无煤柱护巷方式,及9上和9下煤层回采巷道采用外错式和内错式的相结合的布置方式,并研究了相应的支护形式。数值模拟结果表明选择无煤柱护巷方式是合理的,留煤柱护巷方_式支承压力的影响范围比无煤柱护巷大2.5倍,煤柱上垂直应力比无煤柱护巷大2.5~7.5MPa。  相似文献   

7.
本文主要针对Apriori算法采用最小支持度和最小信任度阈值来发现知识,而没有考虑交易中数量问题的不足,提出一种快速的基于频繁模式树FP-tree的最大频繁项目集挖掘算法.该算法不需要产生频繁项集,而且只需要扫描事务数据库D一次,从而提高了算法的执行效率.该方法结合大量的实际项目数据进行关联规则挖掘测试发现,不仅能较好地分析非稠密数据,也能处理现实世界中稠密数据. 结果 表明该优化算法可显著降低关联规则挖掘在数据挖掘工作中的时间开销.  相似文献   

8.
决策树算法是数据挖掘中重要的分类算法,本文首先阐述了数据挖掘中决策树的基本思想,然后针对ID3算法倾向于取值较多的属性的缺点。对ID3算法予以改进,并通过实验对改进前后的算法进行了比较,实验表明改进后的算法是有效的。  相似文献   

9.
Mining education was one of the areas of technical savoir transformed during the eighteenth century. Mining academies arose and spread through Europe in the second half of that century. This happened first in the German states and the Austrian dominions, due to the cameralistic system, and soon developed elsewhere through a transfer of the German model to France (Ecole des mines) as well as to other francophone and Spanish-speaking areas (Belgium and Piedmont-Savoy, Spain and America). The mining academies may rightly be considered among the prototypes of technical high schools (Polytechniques and Technische Hochschulen) established during the nineteenth century. In the course of exploring some of the details of this development, the present paper aims at suggesting outlines to be followed in pursuing a comparative analysis of special schools for the training of technicians and mining officers (Bergschulen and Bergakademien). A second aim is to examine more closely the Italian case as a typical example of adaptation, although on a smaller scale, of French and German experiences. This can provide a framework within which to place further microanalyses and case-studies.  相似文献   

10.
This review focuses on conceptual and methodological advances in our understanding and characterization of the conformational heterogeneity of proteins. Focusing on X-ray crystallography, we describe how polysterism, the interconversion of pre-existing conformational substates, has traditionally been analyzed by comparing independent crystal structures or multiple chains within a single crystal asymmetric unit. In contrast, recent studies have focused on mining electron density maps to reveal previously ‘hidden’ minor conformational substates. Functional tests of the importance of minor states suggest that evolutionary selection shapes the entire conformational landscape, including uniquely configured conformational substates, the relative distribution of these substates, and the speed at which the protein can interconvert between them. An increased focus on polysterism may shape the way protein structure and function is studied in the coming years.  相似文献   

11.
FoodMart超市市场部想提高客户满意度和客户保有率,于是计划对会员卡方案重新定义,以便更好地为客户提供服务并且使提供的服务能够更加密切地满足客户的期望。本文基于对FoodMart超市客户数据的分析,适当选取某些客户类型特征作为决策属性,并利用ID3算法从FoodMart超市客户数据中挖掘客户分类规则。并利用java语言编程实现了ID3算法。仿真的结果不仅为FoodMart超市会员卡重新定义制定最佳的指导策略,而且在理论研究和工程实践中都具有重要的意义。  相似文献   

12.
The suggestion has been made that polyamines may be involved in the control of cell death, since exceedingly high or low levels induce apoptosis in different cell systems. For a deeper insight into the relationship between apoptosis and polyamine metabolism, we investigated in vitro the effect on rat thymocytes of mitoguazone (MGBG, which inhibits S-adenosylmethionine decarboxylase, i.e. a key enzyme in the polyamine biosynthetic pathway). Thymocytes were selected as an especially suitable model system, since they undergo spontaneous apoptosis in vivo and can be easily induced to apoptose in vitro by etoposide, used here as an apoptogenic agent. MGBG protected thymocytes from both spontaneous and drug-induced apoptosis, and this protective effect was associated with a decrease in polyamine oxidase activity and total polyamine levels.Received 7 July 2004; received after revision 2 September 2004; accepted 9 September 2004  相似文献   

13.
D-amino acid oxidase (DAAO) activity was not altered in the liver and kidney by oral administration of D-alanine to adult mice. The enzyme was apparently not induced by the enteric microflora either, since the enzyme activity in the liver and kidney of germ-free mice was not different from that of specific-pathogen-free mice. The times of appearance of DAAO activity and of free D-amino acids in the kidney were elucidated using suckling mice. DAAO activity started to increase 7 days after birth, and reached almost the adult level by 28 days. The content of free neutral D-amino acids also increased with age, in a similar fashion. A possible conclusion is that the enzyme activity normally increases during this period, to eliminate the free D-amino acids which have increased with age in the suckling mice. Consequently, the administration of D-alanine had no further effect in increasing enzyme activity.  相似文献   

14.
基于煤矿深井高温的原因,结合实际的勘查和测定来分析大兴矿采区巷道热害的主要热量来源,并给出各个热源放热量的具体计算方法。运用CFD软件对采区巷道的温度场进行模拟。  相似文献   

15.
D-amino acid oxidase (DAAO) activity was not altered in the liver and kidney by oral administration of D-alanine to adult mice. The enzyme was apparently not induced by the enteric microflora either, since the enzyme activity in the liver and kidney of germ-free mice was not different from that of specific-pathogen-free mice. The times of appearance of DAAO activity and of free D-amino acids in the kidney were elucidated using suckling mice. DAAO activity started to increase 7 days after birth, and reached almost the adult level by 28 days. The content of free neutral D-amino acids also increased with age, in a similar fashion. A possible conclusion is that the enzyme activity normally increases during this period, to eliminate the free D-amino acids which have increased with age in the suckling mice. Consequently, the administration of D-alanine had no further effect in increasing enzyme activity.  相似文献   

16.
结合双鸭山分公司东荣三矿的实际条件,从矿压显现的时空关系及其相互作用规律出发,采用现场测试及数值模拟的实验方法,研究近距离煤层群开采过程中产生的应力场及位移场对回采工作面及其周边巷道的影响;从而确定煤层群开采过程中,采准巷道与工作面开采之间合理的时空关系及其巷道的合理支护方式。  相似文献   

17.
针对晓明矿地质条件,综合运用关键层理论、围岩平衡法、“三带”法、数值分析及巷道探查等方法分析了7#煤层回采后上覆围岩活动规律,确定了上部4—1#煤层的底板下沉量、煤体破坏程度及煤层应力状态以及煤层的连续性和完整性。综合理论分析、数值分析及现场探查结果,判定4—1#煤层上行开采是可行的,并提出回采设计方案,为晓明矿及类似条件矿井进行上行开采提供了参考。  相似文献   

18.
专门对AutoCAD+进行二次开发,在剖面算量法的基础上,提出了一种计算煤岩量关系的方法——量定位置和轧刀算量。以内蒙古霍林河南露天矿为例,针对其复杂的地质条件,实现了在生成的剖面露天境界多边形范围内进行算量,对不同的设计方案快速的计算出煤岩量关系并绘制出V-P曲线,提高了采矿技术.人员编制采矿设计的精度和效率。  相似文献   

19.
结合某铅锌矿矿山垮塌区开采技术条件复杂的工程实际,基于高效安全回采矿石的思想,提出了4种可行的回采方案。运用MIDAS/GTS有限元软件,构建了垮塌区复杂开采条件下的三维数值模型,并采用FLAC3D数值模拟软件对垮塌区的失稳垮塌进行了数值模拟分析,确定垮塌区的影响范围和科学经济的回采顺序,为安全高效地回采矿石提供技术支持。研究表明:0#空区的失稳垮塌影响了5个采场的安全开采;优化后的回采顺序为先确保充填体质量,再由两边向中间开采。  相似文献   

20.
基于三维地质模型的露天矿模拟开采系统应用研究   总被引:1,自引:0,他引:1  
为了实现露天矿三维可视化模拟开采,提出了一种快速构建露天矿三维地质模型的方法——包络面构模法。在建立露天矿数字化三维地形/地质模型的基础上,根据露天矿的实际情况建立三维开采模板,自动生成推进模板,从而实现露天矿的模拟开采,使得多方案设计从中选优成为可能,进而提高了采矿设计的速度和质量。  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号