色谱法测定矿物岩石中的微量氩

钾氩同位素地质年龄测定已广泛地应用于同位素年代学和地质研究工作。这一方法的关键在于对矿物岩石中微量氩的定量分析。由于年轻地质体中矿物岩石的放射性成因氩含量很低,准确定量非常困难。应用气相色谱法对矿物岩石中的微量氩进行测定,是钾氩同位素地质年龄测定工作中一项新的尝试。     

第四纪地质年代学和定年方法及应用

第四纪样品的同位素定年是一个常见的较困难的地质问题。近几年来，由于质谱分析、热电高质谱计、加速器质谱计和样品分离技术的进步，第四纪地质年代学及定年方法发展非常迅速。K－Ar和Ar－Ar定年、14C、铀系、FT、TL和ESR定年等已能为地球演化及第四纪以来古气候及古环境的变化提供准确的时间标尺。宇宙成因核素，例如10Be、26Al、36Cl和39Ar可以用于地球表面的侵蚀定年、冰川作用和冰川消退定年、地下水年龄测定及地球物质形成年龄和暴露年龄的测定，大大提高了测量灵敏度、测量精度和测量速度。这些定年方法在第四纪地质年代学和同位素地质科学中获得了很大进展。上述方法的实现及潜在的应用将在第四纪地质学及地球科学中发挥重要作用。本文讨论了这些方法的特点、优越性、局限性及其意义。     

溅射原子化激光共振电离－飞行时间质谱仪系统的电荷耦合器件大屏幕图像显示系统的研制

研制成功了在溅射原子化共振电离－飞行时间质谱仪上分辨率为１μｍ、观察范围为１６０μｍ×１６０μｍ的电荷耦合器件（ＣＣＤ）大屏幕图像显示系统，利用该系统分析研究了黄铁矿样品中微细粒金的大小及分布情况，并进行了深度分析。     

微机械系统中精密弹性微动工作台的研制及其精度分析

研制了一种低成本、高精度的双层精密弹性微动工作台及其闭环控制系统，并对其精度进行了分析。试验结果表明其分辨力优于０．１μｍ，定位精度优于±０．５μｍ，可作为一般微机械系统中的精密工作台。     

硫酸盐矿物^234U-^230Th热电离质谱测年方法探讨

热电离质谱技术被应用到^234U-^230Th同位素丰度的测定,使该方法的样品用量减小、精度和准确度得到了提高。石膏矿物是蒸发岩中最为普遍的盐类矿物,在湖泊沉积中可容易挑出大量和结晶很好的石膏矿物。由于石膏样品较低的U含量和化学处理的难度较大,     

硫酸盐矿物~(234)U-~(230)Th热电离质谱测年方法探讨

引 言 热电离质谱技术被应用到234U-230 Th同位素丰度的测定,使该方法的样品用量减小、精度和准确度得到了提高。石膏矿物是蒸发岩中最为普遍的盐类矿物,在湖泊沉积中可容易挑出大量和结晶很好的石膏矿物。由于石膏样品较低的U含量和化学处理的难度较大,其234U-230 Th年代一直未得到很好的发展。本工作初步探索了盐湖沉积物中石膏矿物的U和Th的分离提取、并采用高精度热电离质谱测定234U-230Th体系年代。初步给出罗布泊盐类沉积时代。1 U、Th的分离提取方法及同位素测定 石膏矿物中的U、Th的分离提取难度较大,主要是由于分离过程…     

挥发性有机化合物标准样品的碳同位素δ13C测定:以甲酸、乙酸为例

密闭石英管燃烧法制备挥发性有机化合物（VOCs）标准同位素样品时,可有效避免制备过程中因挥发所导致的同位素分馏。以市售高纯度的甲酸、乙酸为标准同位素样品,重复制备它们的同位素分析样各5次,并在Finnigan MAT-252气体同位素比值质谱仪上测定其碳同位素δ¹³C。结果显示此法具有极高的重现性,相对标准偏差分别为0.07% (n=5)、0.04% (n=5)。与之对比,另一套同位素测定系统（气相色谱-燃烧炉-同位素比值质谱,GC/C/IRMS）对同一标准物质的同位素测定结果并无显著差别,但在精度上却明显不及前者。密闭石英管燃烧-气体同位素质谱法的测定误差相对较小,可作为VOCs标准同位素样品的δ¹³C分析方法。     

LA-BrF_5-IRMS直连系统的δ~(17)O和δ~(18)O值测定

激光五氟化溴（即LA-BrF5）法已逐渐成为国际上一种快捷的硅酸盐矿物氧同位素提取方法,并部分地取代常规的BrF5法而应用于地质样品的氧同位素研究上。LA-BrF5法的最大优点是激光产生的高温能够在很短时间内使硅酸盐（包括氧化物）矿物氟化而使氧完全释放出来,因此对那些难熔矿物,如橄榄石、石榴子石、锆石等都是最有效的,它具有反应时间快、样品用量少和原地（in-site）分析（如用UV激光器）等优点。LA-BrF5-IRMS直连（on-line）技术还可以进行?17O值测定,也是这类方法的一大优点,这有助于对陨石[1]和硫酸盐[2]等矿物的17O异…     

LA-BrF5-IRMS直连系统的δ^17O和δ^18O值测定

激光五氟化溴(即LA-BrF5)法已逐渐成为国际上一种快捷的硅酸盐矿物氧同位素提取方法，并部分地取代常规的BrF5法而应用于地质样品的氧同位素研究上。LA-BrF5法的最大优点是激光产生的高温能够在很短时间内使硅酸盐(包括氧化物)矿物氟化而使氧完全释放出来，因此对那些难熔矿物，如橄榄石、石榴子石、锆石等都是最有效的，     

同位素稀释质谱法对年青玄武岩K－Ar年龄的测定

用同位素稀释质谱法在ＲＧＡ－１０质谱计和析Ａｒ仪联合系统中，分析测定了一批年青（第四纪）玄武岩样品的常规Ｋ－Ａｒ年龄。绝大多数样品的年龄值在０．１～０．７Ｍａ之间，只有少数几个样品的年龄值在１～２Ｍａ之间，所测年龄都在第四纪范围内。部分样品经过重复检测获得了良好的重现性，这表明测量精度和准确度都比较高。经检测样品的大气４０Ａｒ／３６Ａｒ比值在２９５．５±５以内。这与当今大气Ａｒ比值２９５．５无明显差别，证明样品不含过剩４０Ａｒ和３６Ａｒ，测得的年龄值是真实可信的。大多数样品的测定误差在±５％以内，仅有少数几个样品的测定误差在±５～±１０％之间，这样的测试水平对年青的第四纪地质样品而言是完全可以接受的。     

Minimal Realization of Linear Graph Models for Multi-physics Systems

An engineering system may consist of several different types of components,belonging to such physical"domains"as mechanical,electrical,fluid,and thermal.It is t...     

INTEGRAL EQUATION METHOD＇S APPLICATION IN HOLE-EDGE STRESS OF COMPOSITE MATERIAL PLATE WITH DIFFERENT SHAPED HOLES

The strength of composite plate with different hole-shapes is always one of the most important but complicated issues in the application of the composite material. The holes will lead to mutations and discontinuity to the structure. So the hole-edge stress concentration is always a serious phenomenon. And the phenomenon makes the structure strength decrease very quickly to form dangerous weak points. Most partial damage begins from these weak points. According to the complex variable functions theory, the accurate boundary condition of composite plate with different hole-shapes is founded by conformal mapping method to settle the boundary condition problem of complex hole-shapes. Composite plate with commonly hole-shapes in engineering is studied by several complex variable stress fimction. The boundary integral equations are founded based on exact boundary conditions. Then the exact hole-edge stress analytic solution of composite plate with rectangle holes and wing manholes is resolved. Both of offset axis loadings and its influences on the stress concentration coefficient of the hole-edge are discussed. And comparisons of different loads along various offset axis on the hole-edge stress distribution of orthotropic plate with rectangle hole or wing manhole are made. It can be concluded that hole-edge with continuous variable curvatures might help to decrease the stress concentration coefficient; and smaller angle of outer load and fiber can decrease the stress peak value.     

Non-monotonic material contrast in scanning ion and scanning electron images

30 keV Ga⁺ focused ion beam induced secondary electron (iSE) imaging was used to determine the relative contrast between several materials. The iSE signal compared from C, Si, Al, Ti, Cr, Ni, Cu, Mo, Ag, and W metal layers does not decrease with an increase in target atomic number Z₂, and shows a non-monotonic relationship between contrast and Z₂. The non-monotonic relationship is attributed to periodic fluctuations of the stopping power and sputter yield inherent to the ion–solid interactions. In addition, material contrast from electron-induced secondary electron (eSE) and backscattered electron (BSE) images using scanning electron microscopy (SEM) also shows non-monotonic contrast as a function of Z₂, following the periodic behavior of the stopping power for electron–solid interactions. A comparison of the iSE and eSE results shows similar relative contrast between the metal layers, and not complementary contrast as conventionally understood. These similarities in the contrast behavior can be attributed to similarities in the periodic and non-monotonic function defined by incident particle–solid interaction theory.     

Application of Feature Extraction through Convolution Neural Networks and SVM Classifier for Robust Grading of Apples

This paper proposes a novel grading method of apples,in an automated grading device that uses convolutional neural networks to extract the size,color,texture,an...     

分布动态载荷识别的抗噪处理

针对正交多项式频域法在用多种响应对矩形薄板进行载荷识别中抗噪性较差的问题,综合运用平均法、矩阵预处理和奇异值截断法等方法对之进行改善,并引入空间映射的思想,将该方法的应用范围拓展为复杂的模型.利用仿真算例,证实了该方法具有较好的抗噪性.     

基于MELTAC-N平台的核电厂安全级DCS环网研究与测试

针对工程实践中环网通讯相关问题的处理缺乏理论基础及国产化安全级DCS平台的开发缺乏成熟经验借鉴问题,对基于MELTAC-N平台核电厂安全级DCS环网的软硬件实现进行了研究。提出了安全级DCS环网双环网冗余设计、光切换开关设计等硬件设计方法,以及以RPR协议为基础,采用全数据收发策略的软件设计方法。在CPR1000安全级DCS平台上对安全级DCS环网的可靠性及实时性进行了评价,并进行了容错能力、响应时间及响应时间稳定性测试验证实验。结果表明,基于MELTAC-N平台安全级DCS环网软硬件设计具有较好的容错能力及响应时间稳定性。     

Short-Term Relay Quality Prediction Algorithm Based on Long and Short-Term Memory

The fraction defective of semi-finished products is predicted to optimize the process of relay production lines, by which production quality and productivity ar...     

End-to-End Multiview Gesture Recognition for Autonomous Car Parking System

The use of hand gestures can be the most intuitive human-machine interaction medium.The early approaches for hand gesture recognition used device-based methods....     

The laboratory simulation of abrasive wear

Abrasive wear has long been recognised as one of the most potentially serious tribological problems facing the operators of many types of plant and machinery; several industrial surveys have indicated that wear by abrasion can be responsible for more than 50% of unscheduled machine and plant stoppages. Locating the operating point of a tribological contact in an appropriate operational ‚map’︁ can provide a useful guide to the likely nature and origins of the surface degradation experienced in use, though care must be exercised in choosing the most suitable parameters for the axes of the plot. Laboratory testing of materials and simulations of machine contacts are carried out for a number of purposes; at one level for the very practical aims of ranking candidate materials or surface hardening treatments in order of their wear resistance, or in an attempt to predict wear lives under field conditions. More fundamentally, tests may be aimed at elucidating the essential physical mechanisms of surface damage and loss, with the longer term aim of building an analytical and predictive model of the wear process itself. In many cases, component surface damage is brought about by the ingress of hard, particulate matter into machine bearing or sealing clearances. These may be running dry although, more usually, a lubricant or service fluid is present at the interface. A number of standardised wear test geometries and procedures have been established for both two- and three-body wear situations, and these are briefly described. Although abrasive wear is often modelled as following an ‚Archard’︁ equation (i.e. a linear increase in material loss with both load and time, and an inverse dependence on specimen hardness) both industrial experience and laboratory tests of particularly lubricated contacts show that this is not always the case: increasing the hardness differential in an abrasively contaminated lubricated pair may not always reduce the rate of damage to the harder surface.     

ANGULAR DISTORTION ALLOWABLE VALUE AND ASSESS METHOD OF WELD ON COKE TOWER

A graph as the new engineering method for estimate the safety of bulging deformation of coke tower is proposed. Through stresses analysis of circumferential weld of coke tower and comparing the stresses produced by pressure with heat stress of steady state, residual stress, bending stress produced by both itself weight and wind loads, it showed that the stresses produced by pressure on the angle distortion are the main factor of equivalent stress of the combined stress. After comparing four kinds of stress controlling conditions, the relation to stress with depth of angular distortion, grade of curvature of angular distortion and half of region of angular distortion has been inferred. Graph of deformation allowable value of coke tower for different condition by angular distortion and half of region of angular distortion has been plotted. The five steps for its engineering use have been explained. The lighter the grade of curvature is, the larger of bulge allowance, may be, and the bigger of depth of angular distortion may pose too. For the coke tower with a popular structure of Dg 5 400 mm×28 mm, the result by graph is nearly more than the result of two formulas formed by other research, the error is less than 7.0%. But, the graph can be easily applied to different size of angular distortion.