Diffusion phenomena of cells and biomolecules in microfluidic devices

Biomicrofluidics is an emerging field at the cross roads of microfluidics and life sciences which requires intensive research efforts in terms of introducing appropriate designs, production techniques, and analysis. The ultimate goal is to deliver innovative and cost-effective microfluidic devices to biotech, biomedical, and pharmaceutical industries. Therefore, creating an in-depth understanding of the transport phenomena of cells and biomolecules becomes vital and concurrently poses significant challenges. The present article outlines the recent advancements in diffusion phenomena of cells and biomolecules by highlighting transport principles from an engineering perspective, cell responses in microfluidic devices with emphases on diffusion- and flow-based microfluidic gradient platforms, macroscopic and microscopic approaches for investigating the diffusion phenomena of biomolecules, microfluidic platforms for the delivery of these molecules, as well as the state of the art in biological applications of mammalian cell responses and diffusion of biomolecules.     

A combined time and frequency domain method for model reduction of discrete systems

A new combined time and frequency domain method for the model reduction of discrete systems in z-transfer function is presented. First, the z-transfer functions are transformed into the w-domain by the bilinear transformation, z = (1+w)/(1?w). Then, four model reduction methods—Routh approximation, Hurwitz polynomial approxima- tion, stability equation, and retaining dominant poles—are used respectively to reduce the order of the denominator polynomials in the w-domain. Least squares estimate is then used to find the optimal coefficients in the numerator polynomials of the reduced models so that the unit step response errors are reduced to a minimum. The advantages of the proposed method are that both frequency domain and time domain characteristics of the original systems can be preserved in the reduced models, and the reduced models are always stable provided the original models are stable.     

Laser-based patterning for fluidic devices in nitrocellulose

In this report, we demonstrate a simple and low cost method that can be reproducibly used for fabrication of microfluidic devices in nitrocellulose. The fluidic patterns are created via a laser-based direct-write technique that induces polymerisation of a photo-polymer previously impregnated in the nitrocellulose. The resulting structures form hydrophobic barriers that extend through the thickness of the nitrocellulose and define an interconnected hydrophilic fluidic-flow pattern. Our experimental results show that using this method it is possible to achieve microfluidic channels with lateral dimensions of ∼100 μm using hydrophobic barriers that form the channel walls with dimensions of ∼60 μm; both of these values are considerably smaller than those that can be achieved with other current techniques used in the fabrication of nitrocellulose-based fluidic devices. A simple grid patterned nitrocellulose device was then used for the detection of C-reactive protein via a sandwich enzyme-linked immunosorbent assay, which served as a useful proof-of-principle experiment.     

全厚进路和分层崩落联合采矿法试验研究

拉么锌矿鱼泉洞矿体在倾斜、低品位的薄矿体开采中,试验研究采用全厚进路和分层崩落联合采矿法试验研究。矿体的矿岩硬度系数f值=6～8,层理发育,平均地质品位Zn=3%～4%;Cu=0.3%～0.5%,原来选择多分段全面留矿法开采方案,后来因为平均品位低而改用这种采矿方法。     

Monolithic integration of fine cylindrical glass microcapillaries on silicon for electrophoretic separation of biomolecules

We demonstrate monolithic integration of fine cylindrical glass microcapillaries (diameter ∼1 μm) on silicon and evaluate their performance for electrophoretic separation of biomolecules. Such microcapillaries are achieved through thermal reflow of a glass layer on microstructured silicon whereby slender voids are moulded into cylindrical tubes. The process allows self-enclosed microcapillaries with a uniform profile. A simplified method is also described to integrate the microcapillaries with a sample-injection cross without the requirement of glass etching. The 10-mm-long microcapillaries sustain field intensities up to 90 kV/m and limit the temperature excursions due to Joule heating to a few degrees Celsius only.     

A three-phase method for patent classification

An automatic patent categorization system would be invaluable to individual inventors and patent attorneys, saving them time and effort by quickly identifying conflicts with existing patents. In recent years, it has become more and more common to classify all patent documents using the International Patent Classification (IPC), a complex hierarchical classification system comprised of eight sections, 128 classes, 648 subclasses, about 7200 main groups, and approximately 72,000 subgroups. So far, however, no patent categorization method has been developed that can classify patents down to the subgroup level (the bottom level of the IPC). Therefore, this paper presents a novel categorization method, the three phase categorization (TPC) algorithm, which classifies patents down to the subgroup level with reasonable accuracy. The experimental results for the TPC algorithm, using the WIPO-alpha collection, indicate that our classification method can achieve 36.07% accuracy at the subgroup level. This is approximately a 25,764-fold improvement over a random guess.     

P2P网络的认证方法研究（英文）

P2P网络离散、动态和自治的特点使得传统的认证方法不能很好的解决其认证问题。本文采用证书和信任值相结合的方式，提出了一个新的认证协议APExSPKI用于解决P2P网络中节点之间的互认证问题。信任值绑定在证书中使得节点在身份认证的同时还可以进行授权和访问控制操作。 此外APExSPKI不需要可信服务器的参与，它允许网络中的任何节点参与到认证的过程中来，参与信任值投票并可充当代理节点来为其他节点颁发证书，这充分体现了节点对等、自治的特点。     

A new method for linear system reduction

A simple and flexible algorithm is presented to find stable reduced models, provided the original system has a set of dominant poles. The proposed technique applies to the multi- variable case as well and provides a parameter to control the approximation for small and large t.     

企业知识资本评估新方法探析--标杆瞄准评估法

本文在总结了企业知识资本评估方法的基础上,提出了一种全新的企业知识资本评估方法,即标杆瞄准评估法。该方法立足于企业之间的对比分析,更易于企业的应用。     

A lemmatization method for Mongolian and its application to indexing for information retrieval

In Mongolian, two different alphabets are used, Cyrillic and Mongolian. In this paper, we focus solely on the Mongolian language using the Cyrillic alphabet, in which a content word can be inflected when concatenated with one or more suffixes. Identifying the original form of content words is crucial for natural language processing and information retrieval. We propose a lemmatization method for Mongolian. The advantage of our lemmatization method is that it does not rely on noun dictionaries, enabling us to lemmatize out-of-dictionary words. We also apply our method to indexing for information retrieval. We use newspaper articles and technical abstracts in experiments that show the effectiveness of our method. Our research is the first significant exploration of the effectiveness of lemmatization for information retrieval in Mongolian.     

A structured method for smart city project selection

The concept of a smart city, based on advanced information and communications technology (ICT), emerged to mitigate the impact of rapid urbanization and was considered feasible. However, the selection of technology and policy for providing better services to citizens and ensuring sustainable development is a multiple-objective decision process that is usually performed by experts in relevant domains. The major goal of this study is to propose a structural method for policy selection, which consists of three phases. In the first phase, the modified Delphi method is used to determine the elements of the decision by surveying panel members for their opinions. In the second phase, an analytic hierarchy process is used to ascertain the priority of each alternative according to the goal of the decision. In the third phase, zero-one goal programming models are developed to select a feasible portfolio based on the political goal and the annual budget. We conducted an empirical study to demonstrate and validate that the proposed model can induce the municipality to consider citizens’ requirements, identify the strengths and weaknesses of proposed policies, and select a feasible project portfolio in response to public expectations. In addition, the study found that a feasible portfolio, including consideration of citizens, business, and the environment, enables the public perceptions of government performance within the resource constraints of the organization.     

A mechanical method for graphical solution of polynomials

A mechanical synthesizer with thirty harmonic elements (fifteen sine components and fifteen cosine components) may be used to graph a polynomial in a complex plane. The sum of the sine components is recorded by a tracing point which moves vertically. The sum of the cosine components is recorded by horizontal motion of a drawing board.     

A two-step iterative method for discrete-time systems reduction

A two-step iterative method (1,2) for a reduction in the order of linear continuous-time systems, given in the state equation or the transfer function, is extended to reduce discrete-time systems. The method requires the optimization of the residues and eigenvalues (or poles) belonging to an objective function. The objective function to be minimized is chosen as the finite sum of the squares of the error between the step responses of the reduced model and the original system. This scheme is continued cyclically until the objective function is satisfactorily minimized. By investigating the initial selection of the eigenvalues in the reduced-order model, it is found that the dominant eigenvalues of the original system give a good approximation. Further, the resulting model is always stable, assuming the original system is stable. As shown in a numerical example, the proposed method is superior to the other methods of model reduction in both steady-state and transient responses, and in the value of the sum of the squares of the error.     

国家自然科学基金项目申请量预测的新方法

近年来,国家自然科学基金项目申请量迅猛增长,申请量预测成为宏观调控这一趋势的重要决策依据。通过深入剖析影响申请量的政策因素和资格因素,开发了一个基于潜在申请者的申请量预测方法。实验结果表明,所提方法的平均相对预测误差显著小于多项式拟合、指数平滑、ARMA模型、灰色G(1,1)模型等常见预测方法。而且,新方法的主要创新性在于其能预估申请政策调控对申请量的影响。