微流体离散点样技术

提出一种制作高密度DNA微阵列的非接触式点样新方法。压电陶瓷低频微振动使得微流体产生均匀的离散和喷射；对微喷嘴内壁进行疏水化处理，从而消除微流体由于湿润作用在微喷嘴内部的自发性流动，使得微喷射具有数字化量可控的特征。通过微流体粘度控制、微喷射速度和微喷射距离的控制消除样点缺陷，获得了均匀的点样样点。通过微喷嘴几何尺寸控制和驱动频率控制获得从飞升到皮升级样点体积，可以用于制作高密度的微阵列。惯性力在微米尺度下仍然起主导作用，可以驱动微流体中微粒的移动，消除微喷嘴堵塞现象。     

一种有效抑制压电打印头残余振动的驱动波形设计

随着压电驱动打印头在工业领域的应用越来越广,打印头喷墨质量越来越多地被人们关注。在压电薄膜驱动打印头喷墨过程中,振动板的残余振动制约着压电打印头的最高喷墨频率,从而影响喷墨质量。通过主动消除振动板的残余振动可以使喷嘴弯液面在墨滴喷射后快速稳定,进而提高打印头的最高喷墨频率。文中提出一种基于负反馈原理的方法来设计压电打印头的驱动电压波形,主动消除振动板的残余振动。通过在对振动板残余振动时实时加载由喷嘴液面平均速度反馈的消振电压,快速消除残余振动。数值模拟结果和多普勒测量实验结果表明该设计方法可以有效抑制振动板残余振动。     

基于微喷技术的微胶囊制造实验研究

利用压电驱动器产生的低频振动，使微流道中的流体产生脉冲流动，通过微喷头实现微流体的数字化离散和喷射。通过控制振动的频率和微喷头的直径，可以实现微胶囊尺寸的数字化控制。利用悬浮交联微胶囊制备方法，以海藻酸钠包覆胰岛细胞进行了微胶囊制作实验，制造出了尺寸均匀的微米级尺度微胶囊。展望了基于微流体数字化的微胶囊制造技术的发展前景。     

微流体数字化技术制备基因芯片微阵列

采用以脉冲为微流动基本形态、脉冲当地惯性力为主动力的微流体数字化技术进行了基因芯片微阵列制备实验.在搭建的基于微流体数字化技术的基因芯片微阵列制备系统上,实验验证了脉冲点样系统参量(收敛角2θ、微喷嘴内径d、电压幅值U和驱动频率f)对样点直径和脉冲点样稳定性的影响规律.以实验规律为依据,提出了制备样点直径约为100 μ...     

聚合物熔体微滴喷射装置设计

针对现有3D打印制造技术对材料种类与形状的限制,结合现有微滴喷射制造技术,设计出了一种由螺杆挤出建压系统,电磁铁驱动的机械冲击系统,加热系统,温控系统和三维移动平台组成的聚合物熔体微滴喷射装置,并介绍了其工作原理。采用PP(聚丙烯)粉料作为熔体微滴喷射装置试验用料,通过调节加热温度,螺杆转速,机械冲击脉冲频率,喷嘴和基台距离等工艺参数和机械参数,实现了均匀可控的熔体输送和熔滴喷射,极大的拓展了传统聚合物3D打印所需材料种类与形状限制。     

数字化微喷射用直列微喷嘴制作工艺

为解决玻璃微管道拉制工艺制作的单孔微喷嘴存在容易脆断,微管道长度不易控制,微喷射效率低等问题,提出了一种新的微喷嘴制作工艺.该工艺延续了微喷嘴拉制工艺中非IC工艺和低成本的制作特点,仍以低流阻的圆截面为喷口形状,通过材料流变运动和冷却时收缩率不同,将多根微管道紧密嵌入到塑料管中;通过毛细腐蚀作用.制作出变内径的锥形管,并实现微喷管长度的控制.制作了内径50 μm的 4 孔微喷嘴和 lO 孔微喷嘴,锥管长为750 μm,微喷管长2.5mm.使用制作的微喷嘴在微流体数字化驱动平台上进行了水性液体在油相和气相中的微喷射实验,制备了 80 μm的微滴和微滴阵列.实验表明,该工艺制作的直列微喷嘴可以在微流体数字化驱动下实现较好的数字化微喷射效果.     

基于ARM9嵌入式技术的滚筒式点样仪控制系统

为实现高精度、高速度的生物芯片制备,研发了一种新型滚筒式点样仪,着重描述了点样仪的机械结构设计、硬件系统以及软件系统的设计。以基于ARM9嵌入式微处理器带有触摸屏的控制器为控制核心,实现了点样仪的高精度双闭环控制。利用频闪观测系统和压电式微喷法使点样仪进行精确的微量喷射。采用C语言编写ARM9底层程序,研发了点样仪的软件系统,从而实现了全自动点样。最后通过微喷实验对不同驱动参数下的样点直径进行了测试,测试结果表明:微喷射稳定性好,样点平均直径较小,满足控制要求。     

新型纳升级点样微喷系统的研制

点样微喷头是非接触法点样的关键部件.在对自行研制的压电陶瓷微喷头进行理论分析的基础上,得到了驱动压电陶瓷微喷头的具体条件.并利用单片机和波形发生芯片制成了数控驱动系统.利用这种驱动系统可以时微喷头实现完全数字控制并进行了喷射实验,得到单个液滴的体积约为0.11 nL的结果.还讨论了驱动电压以及脉冲宽度对于液滴体积和初速度的影响.     

直列微喷嘴制作工艺及数字化微喷射实验

摘要：采用玻璃微管道拉制工艺制作的单孔微喷嘴存在着容易脆断,微管道长度不易控制,微喷射效率低等问题。为此设计了一种新的微喷嘴制作工艺,该工艺延续了微喷嘴拉制工艺中非IC工艺和低成本的制作特点,仍以低流阻的圆截面为喷口形状,通过材料流变运动和冷却时收缩率不同将多根微管道紧密嵌入到塑料管中;通过毛细腐蚀作用,制作出变内径的锥形管,同时也达到了控制微喷管长度的目的。制作了内径50μm的4孔微喷嘴和10孔微喷嘴,锥管长为750μm,微喷管长2.5mm。使用制作的微喷嘴在微流体数字化驱动平台上进行了水性液体在油相和气相中的微喷射实验,制备了80μm的微滴和微滴阵列。实验表明该工艺制作的直列微喷嘴可以在微流体数字化驱动下实现较好的数字化微喷射效果。     

自激振动空化射流振动分析试验

从提高喷射喷嘴的设计效率和射流冲蚀与清洗效率角度出发,在理论分析自激振动空化喷嘴工作原理的基础上,设计不同尺寸组合的风琴管自激振动空化喷嘴,测量风琴管自激振动空化喷嘴喷射时喷嘴及射靶的振动,通过对振动信号的比较分析,研究自激振动空化射流振动特性及频率特性。结果表明,自激振动空化喷嘴振动频域图中的高频成分是谐振腔内空化泡破裂撞击导致的高频振动,自激振动空化喷嘴振动频域图中存在调制频率,即喷嘴谐振腔内自激振动的谐振频率。实测值与理论计算值相符。给出风琴管自激振动空化喷嘴的主要结构参数喷嘴直径、谐振腔长对喷嘴产生自激振动空化效果的影响规律,得出给定试验系统中自激振动空化喷嘴的最佳结构参数。振动分析试验研究与仿真研究结果一致,为自激振动空化喷嘴的优化设计提供了有效方法。     

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.