注浆法在已建油罐地基加固中的应用

在一定的压力作用下,将水泥浆注入松散的地基土中,浆液凝固后将松散的土粒固结在一起,对地基进行加固。这种方法具有省时、省工、省费用、使用简单方便等优点。特别是对已建油罐地基的处理更有其独到之处。由于钻孔可在任意角度下进行,因此可对罐基础任何区域进行加固并达到较好的效果。文章对钻孔布置、钻孔、注浆花管布置、压力灌浆、充水预压等几项关键技术进行了较详细的论述。     

用MATLAB研究聚丙烯腈湿法纺丝的凝固过程

以聚丙烯腈二甲基亚砜溶液为纺丝液,二甲基亚砜水溶液为凝固液的湿法纺丝体系为例,借助MATLAB研究湿法纺丝凝固过程;通过编写MATLAB程序,求解凝固过程的数学模型,得到溶剂(二甲基亚砜)与非溶剂(水)在凝固过程中与时间和空间关系的三维图;通过改变模型参数考察纺丝条件对凝固进程的影响.结果是:增加纺丝液中的固含量,则延长初生纤维凝固的时间;而升高凝固浴温度则缩短凝固时间.增加纺丝液固含量或降低凝固浴温度可缓和凝固进程,增加凝胶化时间,对于获得结构均匀、致密的纤维有利.本文编写的程序给数学模型求解带来便利,通用性好,可用于求解其它类似的数学模型.     

Local controllability of quantum systems

We give a criterion that is sufficient for controllability of multipartite quantum systems. We generalize the graph infection criterion to the quantum systems that cannot be described with the use of a graph theory. We introduce the notation of hypergraphs and reformulate the infection property in this setting. The introduced criterion has a topological nature and therefore it is not connected to any particular experimental realization of quantum information processing.     

Quantifying channels output similarity with applications to quantum control

In this work, we aim at quantifying quantum channel output similarity. In order to achieve this, we introduce the notion of quantum channel superfidelity, which gives us an upper bound on the quantum channel fidelity. This quantity is expressed in a clear form using the Kraus representation of a quantum channel. As examples, we show potential applications of this quantity in the quantum control field.     

聚丙烯腈丝条水洗过程中残留DMSO扩散规律的研究

在聚丙烯腈原丝生产过程中,水洗对原丝的结构和性能有重要影响。研究了不同水洗条件下残留DMSO的溶出规律,通过Fick定律建立了溶剂的扩散数学模型,得到不同条件下的扩散系数值,并且通过实验值对其进行修正。借助压汞法考察了不同水洗条件下丝条的孔隙结构参数变化,结果表明:丝条中存在着丰富的微孔,超声波的加入使丝条平均孔径减小。孔结构的变化改变扩散系数,孔隙率增大时扩散系数增大。     

System-level reliability assessment of mixed-signal convergent microsystems

The next-generation convergent microsystems, based on system-on-package (SOP) technology, require up-front system-level design-for-reliability approaches and appropriate reliability assessment methodologies to guarantee the reliability of digital, optical, and radio frequency (RF) functions, as well as their interfaces. Systems approach to reliability requires the development of: i) physics-based reliability models for various failure mechanisms associated with digital, optical, and RF Functions, and their interfaces in the system; ii) design optimization models for the selection of suitable materials and processing conditions for reliability, as well as functionality; and iii) system-level reliability models understanding the component and functional interaction. This paper presents the reliability assessment of digital, optical, and RF functions in SOP-based microsystems. Upfront physics-based design-for-reliability models for various functional failure mechanisms are presented to evaluate various design options and material selection even before the prototypes are made. Advanced modeling methodologies and algorithms to accommodate material length scale effects due to enhanced system integration and miniaturization are presented. System-level mixed-signal reliability is discussed thorough system-level reliability metrics relating component-level failure mechanisms to system-level signal integrity, as well as statistical aspects.     

Reliability of fine-pitch through-vias in glass interposers and packages for high-bandwidth computing and communications

Glass is an ideal substrate material to enable 2.5D and 3D packaging of ICs at low cost and high performance. However, it is a brittle material and is prone to failures during fabrication and operation. Large coefficient of thermal expansion (CTE) mismatch between copper and glass leads to thermomechanical stresses that can lead to glass cracking and delamination from glass interfaces. This paper focuses on modeling and reliability characterization of copper-plated through-package-vias (TPV) in glass packages. Thermomechanical simulations were carried out to obtain design guidelines for reliable TPVs in glass. Test-vehicles with different glass thicknesses and copper TPV fabrication conditions were fabricated for thermal cycling tests, resistance monitoring and failure analysis. The reliability characterization results showed good thermomechanical reliability of TPVs in ultra-thin glass panels.     

湿法纺丝条件对临界凝固时间的影响

以聚丙烯腈-二甲基亚砜-水体系为研究对象,通过建立数学模型,对聚丙烯腈湿法纺丝凝固的初期阶段进行研究。借助MATLAB软件,采用有限元法对数学模型进行求解。利用数学模型考察纺丝条件对纺丝液临界凝固时间的影响。结果表明:(1)凝固浴浓度在一定程度上决定凝固进程;纺丝液临界凝固时间随凝固浴浓度升高而增加,且增加的趋势是越来越快,当浓度大于60%尤为明显;(2)纺丝液临界凝固时间随纺丝液中水含量的增加而减小,使纺丝液凝固时发生瞬时相分离的趋势增大;(3)随着喷丝孔直径的增加,纺丝液临界凝固时间会延长。     

Exercise echocardiography with left atrial stimulation: advantages and limitations of the method

Exercise echocardiography seems a relatively reliable diagnostic technique for evaluation of patients with coronary artery disease. The prognostic aspects of the stress echo have widely been documented with the use of various stressors (exercise, dipyridamole, dobutamine, pacing). Rapid atrial pacing echocardiography is highly specific and sensitive technique for the detection of the coronary disease, especially in patients who are unable to perform an active stress test. This technique minimizes the factors decreasing image quality during exercise (chest wall movements and hyperventilation). Exercise echocardiography is safe, relatively cheap, and can be done in every hospital.     

可见光响应型尖晶石纳米粉体的制备及其光催化还原性能

采用柠檬酸络合溶胶-凝胶法制备CoAl_2O_4、MgFe_2O_4和CoFe_2O_4三种可见光响应型尖晶石纳米粉体,分别用UV-Vis、XRD和SEM对其光电活性、晶体结构和形貌进行表征。结果表明,三种催化剂均属尖晶石结构,颗粒呈近球形和不规则形状,粒子尺寸约(3～20)nm,光吸收极限波长800 nm,计算得到禁带宽度E_g1.55 eV。在模拟日光灯照射下,进行光催化还原CO_2制取甲酸的研究,结果表明,三种催化剂均有较好的活性,CoFe_2O_4的催化能力较强,光照5 h,甲酸收率达4 943.11 μmol·g~(-1)。