基于GA参数辨识的直流伺服电机PID调节器的设计     

冯常奇  江品力 《南京气象学院学报》2014,6(4):312-315

针对数控火焰切割机自动调高系统的特点和要求,采用遗传算法对其位置调节器PID参数进行全局优化辨识,有效地解决了直流伺服电机的控制精度和快速性的问题.仿真结果表明,与传统的参数辨识法相比,遗传算法参数寻优使自动调高系统的动态性能大幅提高,具有很强的鲁棒性.  相似文献   

凉山瓦西乡南红玉中的赤铁矿包裹体特征与成因     

张良钜  宋楚欣  阮青锋  曾伟来  李东升  曾南石  胡惠驿  覃敏锋 《岩石矿物学杂志》2015,34(2):237-245

瓦西乡产出的南红玉中的红色点状及火焰纹典型包裹体分别是石英中的红色球粒与红色管状包裹体。鏡下及扫描电镜(SEM)研究,红色球粒分布在"三色"层水晶的菱面体单形晶面的间歇层面中,由红色核、黑色壳和红色表层组成;火焰纹管状包裹体主要出现在条带水晶中,管的方向垂直水晶的菱面体晶面,管的内壁呈黑色,外壳为红色。其球粒表层或管外壳的颜色、厚度及透光性则直接影响南红的颜色质量与润泽性。研究表明,球粒状和火焰状包裹体主要由片状、鳞片状或板片状赤铁矿组成;球粒圈层中的赤铁矿晶体c轴取向呈规律变化,可能与其V2O5含量有关。据水晶晶体中的球粒、管及共生矿物绿帘石、黄铜矿包裹体的红外光谱(IR)及流体包裹体均一法测温与激光拉曼(LRS)分析,球或管的赤铁矿属含有机质的低温热液(约160℃)成因,成矿溶液中的有机质也是促使铁氧化物凝聚形成具不同圈层结构的红色球粒与管的主要原因。有机质可能来自下二叠统茅口组碳酸盐。  相似文献   

白云母、高岭石矿物中羟基的o同位素分析方法研究     

李延河  蒋少涌 《地球学报》1999,20(1):63-66

羟基矿物内部存在两种位于不同结构位置上的氧原子硅氧四面体氧和羟基氧,二者之间的Ｏ同位素分馏可能比任何共生矿物对都大,是一种潜在的单矿物同位素地质温度计。单矿物同位素地质温度计较矿物对同位素地质温度计有很多优点。准确测量矿物中羟基的Ｏ同位素组成是建立单矿物同位素地质温度计的关键。本文介绍了一种精确测量白云母、高岭石矿物中羟基的Ｏ同位素组成的新方法火焰加热真空脱水氟化法。δ１８ＯＯＨ的分析精度达到０３‰,羟基氧的提取率达到９９％～１００％。实验证明羟基矿物在高温真空脱水过程中不存在Ｏ同位素动力学分馏,羟基水  相似文献   

Organohalogen compounds in deep-sea fishes from the western North Pacific, off-Tohoku, Japan: Contamination status and bioaccumulation profiles     

Shin Takahashi  Tomoko Oshihoi  Tomohiko Isobe  Tsunemi Kubodera 《Marine pollution bulletin》2010,60(2):187-196

Twelve species of deep-sea fishes collected in 2005 from the western North Pacific, off-Tohoku, Japan were analyzed for organohalogen compounds. Among the compounds analyzed, concentrations of DDTs and PCBs (up to 23,000 and 12,400 ng/g lipid wt, respectively) were the highest. The present study is the foremost to report the occurrence of brominated flame retardants such as PBDEs and HBCDs in deep-sea organisms from the North Pacific region. Significant positive correlations found between δ¹⁵N (‰) and PCBs, DDTs and PBDEs suggest the high biomagnification potential of these contaminants in food web. The large variation in δ¹³C (‰) values observed between the species indicate multiple sources of carbon in the food web and specific accumulation of hydrophobic organohalogen compounds in benthic dwelling carnivore species like snubnosed eel. The results obtained in this study highlight the usefulness of deep-sea fishes as sentinel species to monitor the deep-sea environment.  相似文献   

MAGNETOTELLURIC SOUNDING AND LATERAL INHOMOGENEITIES IN THE LITHOSPHERE     

《International Geology Review》2012,54(11):1340-1369

ABSTRACT

Libyan Desert Glass (LDG), rediscovered in modern times in 1932, is an ultrahigh-temperature glass composed of nearly pure SiO₂. LDG is found as surface float in Egypt’s Libyan (Western) Desert, its strewnfield defined by the intersection of major faults. Extra-terrestrial components are present in LDG but there is no associated impact crater. LDG is not an impactite, nor do pieces exhibit aerodynamic forms. Extremely viscous silica remained hot long enough to flow several centimetres. Additional constraints on the origin of LDG are imposed by exotic materials found nearby: a dark 30-gram granular micro-diamond mass, mullite-magnetite-silica glass rocks with micro-diamonds, lumps of fine-grained magnetite, titanium filaments, titanium nitride, titanium aluminide, aluminium oxycarbonitride, phosphides, silver, zirconium, zinc, carbonaceous grains, and metal grains coated with carbonaceous materials. The region is underlain by 500–3000 m of flat-lying sandstone composed of quartz grains and little else. To account for LDG and the other unusual materials and nearby outgassing vents, serpentinization is evoked. Products of this complex low-temperature crustal process include serpentine, magnetite, aqueous silica, and great quantities of hydrogen. The hydrogen, produced in Basement rocks beneath the sandstones, may have risen along faults, passing around grains of quartz (with which it does not react) until slowed by tight conditions, perhaps self-sealed by silica produced during serpentinization. Columns of quartz hundreds or thousands of metres high with intergranular spaces filled with H₂ (±CH₄) may have been established with some hydrogen leaking into the surface domain while still more was produced at depth. Disturbance by occasional impacts or airbursts, large or small, would violently release great columns of pressurized hydrogen, which, ignited, would burn until exhaustion. Such sustained heating events could be repeated. Exotic products might come from materials formed cold in the outer solar system, transformed in a great flickering flame with temperatures perhaps exceeding 1800°C.  相似文献   

电感耦合等离子体发射光谱法和火焰原子吸收光谱法连续测定化探样品中12个元素   总被引：3，自引：3，他引：0  

于阗  张连起  陈小迪 《岩矿测试》2011,30(1):71-74

建立了地质化探样品中不同含量和检出限要求的12个元素的连续测定方法。样品经一次取样,用盐酸-氢氟酸-硝酸-高氯酸溶样,电感耦合等离子体发射光谱法测定铜、铅、锌、钴、镍、镉、锶、钡、钒、锰后,加碘化钾-甲基异丁基甲酮萃取分离,火焰原子吸收光谱法测定银、镉。银、镉的相对标准偏差(RSD,n=12)分别为6.5%、4.7%。与现行分析方法相比,建立的方法灵敏度和精密度高、准确度好,降低了生产成本,缩短了检测时间,尤其适合大量化探样品的测定。  相似文献   

有机溴化物的溴同位素测试技术及其生物地球化学指示意义   总被引：2，自引：0，他引：2  

单慧媚  马腾  刘存富  刘玲  杨杰 《地球科学进展》2011,26(8):811-821

有机溴化物已成为继有机氯化物之后又一值得关注的全球性新兴持久性有机污染物。稳定Br同位素测试技术的快速发展,为有机溴化物生物地球化学循环研究提供了更为有效的技术支撑。在综述稳定Br同位素研究进展的基础上认为：①基于GC-MC-ICPMS技术基础上的有机单体Br同位素（CSIA-OBr）是Br同位素研究的主要趋势,难点是...  相似文献   

火焰原子吸收光谱法测定固态磷矿散源中的钾钠     

刘容春 《矿物岩石》2000,20(3):100-101

本文研究了用微波炉在自制聚四氟乙烯闭容器内,用ＮＨＯ３－ＨＦ增压分解样品,即解决了样品分解的难题,又减少了污染。并于标准系列中外加基体元素消除了基本的干扰,以ＦＡＡＳ测定Ｋ２Ｏ和Ｎａ２Ｏ。  相似文献   

放射性氡气测量动态监测煤炭地下气化燃空区   总被引：4，自引：1，他引：3  

刘菁华  王兴泰  田钢  王祝文 《物探与化探》2000,24(2):92-98

煤炭地下气化是将地下的煤炭进行有控制的燃烧,为了使煤的燃烧和气化得到有效的控制,了解燃烧的火焰工作面的移动速度以及燃空区的范围是致关重要的。唐山刘庄煤矿地下气化区的试验中,分析了放射性测氡法在进行煤炭地下气化监测中确定燃烧火焰工作面的移动速度及以燃空区范围的可行性和有效性,从而提出一些建议。  相似文献   

Truncated flame structures within a deposit of the Indian Ocean Tsunami: evidence of syn‐sedimentary deformation     

DAN MATSUMOTO  HAJIME NARUSE  SHIGEHIRO FUJINO  APICHART SURPHAWAJRUKSAKUL  THANAWAT JARUPONGSAKUL  NORIHIKO SAKAKURA  MASAFUMI MURAYAMA 《Sedimentology》2008,55(6):1559-1570

This study reveals the three‐dimensional morphology and syn‐sedimentary formation processes of a deformation structure termed ‘truncated flame structures’ which is found in a terrestrial tsunami deposit in southern Thailand that formed during the 2004 Indian Ocean Tsunami. The structure was found at the boundary between a lower fine‐grained layer and an upper coarse‐grained layer that are related to two runup events. In order to confirm the morphology of the structure, the authors excavated two trenches and an opencast pit. When viewed in a cross‐section oriented parallel to the direction of the runup current, the deformed boundary has an irregularly bulging profile, similar to that observed in flame structures. The protruding structures are inclined towards the downstream direction of the runup current, and are truncated horizontally along their upper surface by parallel laminations in the overlying layer. When viewed in a cross‐section oriented perpendicular to the current direction, it appears that parts of the upper layer descend into the lower layer as lobate masses. In places, these masses are completely detached from the main part of the upper layer, forming circular or elliptical shapes. The contact between the lower layer and the main part of the upper layer is a planar truncation surface. Opencast excavation of the contact surface revealed that the deformed structures have flat, sinuous horseshoe crests that open in a downstream direction. It is possible for the runup current to generate shear stress such that it deforms the boundary into a truncated flame structure. Moreover, the observations made in this study indicate the syn‐sedimentary development of the structure: deformation and truncation occurred simultaneously in association with the runup current that formed the upper layer. Truncated flame structures can be used as a criterion in identifying the syn‐sedimentary deformation of substrate: the structures are indicative of unidirectional flow with sufficiently high shear velocity to deform unconsolidated substrate. As in the present case, the truncated flame structures may be characteristic of tsunami events that involve strong unidirectional currents on land due to the extraordinarily long wave period of tsunamis, rather than other events such as storm surges or flooding.  相似文献