Alternating current-dielectrophoresis driven on-chip collection and chaining of green microalgae in freshwaters

The capability of the AC dielectrophoresis (DEP) for on-chip capture and chaining of microalgae suspended in freshwaters was evaluated. The effects of freshwater composition as well as the electric field voltage, frequency, and duration, on the dielectrophoretic response of microalga Chlamydomonas reinhardtii were characterized systematically. Highest efficiency of cell alignment in one-dimensional arrays, determined by the percentage of cells in chain and the chain length, was obtained at AC-field of 20 V mm⁻¹ and 1 kHz applied for 600 s. The DEP response and cell alignment of C. reinhardtii in water sampled from lake, pond, and river, as well as model media were affected by the chemical composition of the media. In the model media, the efficiency of DEP chaining was negatively correlated to the conductivity of the cell suspensions, being higher in suspensions with low conductivity. The cells suspended in freshwaters, however, showed anomalously high chaining at long exposure times. High concentrations of nitrate and dissolved organic matter decrease cell chaining efficiency, while phosphate and citrate concentrations increase it and favor formation of longer chains. Importantly, the application of AC-field had no effect on algal autofluorescence, cell membrane damage, or oxidative stress damages in C. reinhardtii.     

Analysis of Nonlinear Systems with Stochastic Input and Stochastic Parameters

This paper gives an extension of the Volterra-functional method to the analysis of nonlinear systems with both stochastic input and stochastic parameters. In Section II, first-order linear systems with stochastic input and stochastic parameter are analyzed. Certain definitions and symbolic relations are established. A special example in which the stochastic input and the stochastic parameter are closely related is given in Appendix I. Section III deals with the analysis of first-order nonlinear systems with both stochastic input and stochastic parameter, by means of the Volterra-functional method. A simpler analysis by extension of the Transform-ensemble method is given in Appendix II. Section IV presents the detailed analysis of nonlinear stochastic systems with four illustrative examples. The analysis can be extended to a class of nonlinear stochastic systems with higher-order linear plants with constant or time-varying parameters.     

Broadcast diamond channel: Transmission strategies and bounds

This paper proposes a new multiuser communication model in which a source with broadcast capabilities wants to transmit two different messages to two different destinations in the case that no direct links between the source and its destinations. In this channel model, two parallel half-duplex relays are used to extend the transmission. For this communication model, an outer bound to the achievable capacity is initially derived. Then, two distinctive transmission schemes are characterized such that the source can transmit to the two destinations. In each scheme, the transmission is split into two phases. Specifically, in the first phase, the source can broadcast different messages to the two relays. Then, in the second phase, the two relays can forward the source’s signals into their destinations. Based on the transmission on each scheme, the achievable rate region is characterized. Further, we derive the optimal duration of each phase. The theoretical analyses are followed by many numerical examples that compare between the different transmission techniques and also show the points at which the capacity is achieved.     

生命科学知识的普及以及进化论的研究有待加强

生命科学在上世纪后50年的快速发展,特别是近十几年来生物技术日新月异的进展以及生物经济时代的迅速临近,使生命科学一跃而成为最受人们关注的一门科学。生命无穷的奥秘,诱发出人们对探究这种奥秘的极大兴趣。更由于生命科学与人的生活、健康和环境密切相关,使人对其格外重视。人类要想了解自己的过去、现在和将来,也必须要学习和研究生命科学。人的正确的宇宙观、世界观的形成,国民素质的提高,都要求用生命科学的知识武装自己。生命科学的发展实质上不仅与个人,而且与民族和国家的发展,甚至与地球的未来都息息相关。随着生命科学知识与时…     

Counting spanning trees in the graphs of Kleitman and Golden and a generalization

A new calculation is given for the number of spanning trees in a family of labelled graphs considered by Kleitman and Golden, and for a more general class of such graphs.     

A fast and versatile cross-linking strategy via o-phthalaldehyde condensation for mechanically strengthened and functional hydrogels

Fast and catalyst-free cross-linking strategy is of great significance for construction of covalently cross-linked hydrogels. Here, we report the condensation reaction between o-phthalaldehyde (OPA) and N-nucleophiles (primary amine, hydrazide and aminooxy) for hydrogel formation for the first time. When four-arm poly(ethylene glycol) (4aPEG) capped with OPA was mixed with various N-nucleophile-terminated 4aPEG as building blocks, hydrogels were formed with superfast gelation rate, higher mechanical strength and markedly lower critical gelation concentrations, compared to benzaldehyde-based counterparts. Small molecule model reactions indicate the key to these cross-links is the fast formation of heterocycle phthalimidine product or isoindole (bis)hemiaminal intermediates, depending on the N-nucleophiles. The second-order rate constant for the formation of phthalimidine linkage (4.3 M⁻¹ s⁻¹) is over 3000 times and 200 times higher than those for acylhydrazone and oxime formation from benzaldehyde, respectively, and comparable to many cycloaddition click reactions. Based on the versatile OPA chemistry, various hydrogels can be readily prepared from naturally derived polysaccharides, proteins or synthetic polymers without complicated chemical modification. Moreover, biofunctionality is facilely imparted to the hydrogels by introducing amine-bearing peptides via the reaction between OPA and amino group.     

Stochastic control and time scheduling for irregular robots

Vehicles of different sizes are difficult to navigate in close vicinity. In this paper, we propose multi-vehicle coordination strategy by stochastic control and time scheduling to guarantee no collisions. We use contours and relative motions of vehicles to calculate collision time and use it in multi-vehicle scheduling and reduce computation burden. The proposed strategy enables the vehicles to add calculation delay when vehicles are moving towards the destinations. To avoid complicated control rule design for motion-restricted irregular vehicles, we propose stochastic control to provide satisfactory performance. By changing the frequency of control update, a modification is proposed to take congestion into account. Simulation examples are given to demonstrate the effectiveness of the proposed approach.     

黑龙江省推广TRIZ理论方法的SWOT分析与有关策略

知识经济时代,创新成为各个国家谋求发展的重要战略手段,而创新离不开创新方法的支持,TR IZ理论作为促进创新的一种有效方法,得到了我国及黑龙江省政府部门的充分重视。采用SWOT分析方法,对黑龙江省推广TR IZ理论方法所具有的优势、劣势以及面临的机遇与挑战进行了系统分析,并提出有关策略,旨在为促进黑龙江省TR IZ理论方法推广、提升黑龙江省创新能力提供有效的方法与决策支持。     

Stochastic bipartite consensus with measurement noises and antagonistic information

This paper is dedicated to the stochastic bipartite consensus issue of discrete-time multi-agent systems subject to additive/multiplicative noise over antagonistic network, where a stochastic approximation time-varying gain is utilized for noise attenuation. The antagonistic information is characterized by a signed graph. We first show that the semi-decomposition approach, combining with Martingale convergence theorem, suffices to assure the bipartite consensus of the agents that are disturbed by additive noise. For multiplicative noise, we turn to the tool from Lyapunov-based technique to guarantee the boundedness of agents’ states. Based on it, the bipartite consensus with multiplicative noise can be achieved. It is found that the constant stochastic approximation control gain is inapplicable for the bipartite consensus with multiplicative noise. Moreover, the convergence rate of stochastic MASs with communication noise and antagonistic exchange is explicitly characterized, which has a close relationship with the stochastic approximation gain. Finally, we verify the obtained theoretical results via a numerical example.     

Optimal adaptive reset control with guaranteed transient and steady state tracking error bounds

In this paper, a solution for improvement of transient performance in adaptive control of nonlinear systems is proposed. An optimal adaptive controller based on a reset mechanism and a prescribed performance bound is devised. The suggested controller has the structure of adaptive backstepping controller in which the estimated parameters are reset to an optimal value. The designed controller ensures both the transient bound and the asymptotical convergence of the states. It is shown that the tracking error satisfies the prescribed performance bound all the time, besides the speed of the convergence rate is increased by resetting the estimated parameters. The results have been proved through both the analytical and simulation studies. The proposed method is applied to an Augmented Quarter Car Model as a case study. Simulation results verify the established theoretical consequences that the prescribed performance bound based optimal adaptive reset controller can enhance the transient performance of the adaptive controller.     

Spectral and graph-theoretic bounds on steady-state-probability estimation performance for an ergodic Markov chain

Motivated by the wide application of Markov-chain steady-state-probability estimation, we pursue a spectral and graph-theoretic performance analysis of a classical estimator for steady-state probabilities here. Specifically, we connect a performance measure to estimate the structure of the underlying graph defined on the Markov-chain's state transitions. To do so, (1) we present a series of upper bounds on the performance measure in terms of the subdominant eigenvalue of the state transition matrix, which is closely connected with the graph structure; (2) as an illustration of the graph-theoretic analysis, we then relate the subdominant eigenvalue to the connectivity of the graph, including for the strong-connectivity case and the weak-link case. We also apply the results to characterize estimation in Markov chains with rewards.     

加强对长江三角洲及沿江开发关键问题的研究

长江三角洲是我国继珠江三角洲开发开放之后又一经济增长最快、发展最好的地区。这一地区以上海为经济中心,自然条件优越,原有经济基础好,工农业生产门类齐全,文化教育与科技发达,是长江流域也是全国最大的经济核心区。按经济总量,长江三角洲一直居我国各大经济区之首,其土地面积仅占全国1%,人口占全国6%,1995年国内生产总值占全国的16%,2001年国内生产总值达到19130亿元,占全国18.7%,比1995年上升了2.7个百分点,体现了经济区的快速发展势头和集聚效应。长江三角洲处于我国东部沿海的中部,经济腹地深广,自浦东开放开发以来,已成为国内外新的…     

IGCNN-FC: Boosting interpretability and generalization of convolutional neural networks for few chest X-rays analysis

Computer-aided diagnosis (CAD) with convolutional neural networks (CNNs) has been widely applied to assist doctors in medical image analysis. However, most of them often encounter two obstacles: (1) Data scarcity, because the advanced performance of CNNs heavily depends on a large amount of data, especially high-quality annotated ones. (2) Interpretability, CNNs cannot directly provide evidence related to the decision-making process to support their diagnosis results. To overcome these two obstacles, we propose an interpretable deep learning framework based on CNNs. Specifically, we introduce a multi-scale loss-based attention to leverage the mid- and high-level features to mine significant features for decision-making. Additionally, to better explore the semantic knowledge from training data, we utilize the mixup method to produce more annotated training images. Moreover, to boost model generalization capability, we employ the self-distillation to learn the knowledge generated from previous training epochs. Experiments on two benchmark Chest X-ray datasets demonstrate the effectiveness of the proposed framework with superior performance over recent SOTA methods, with boosting model interpretability.     

Absolute stability of uncertain discrete Lur’e systems and maximum admissible perturbed bounds

The robust absolute stability problem for norm uncertain and structured uncertain discrete Lur’e systems is considered in this paper by using Lyapunov function method. A sufficient condition of absolute stability for discrete Lur’e systems is established in terms of linear matrix inequalities (LMIs) or the equivalent frequency-domain condition. We compare the result with the Popov-like criterion (Tsypkin criterion) and extended strictly positive real (ESPR) lemma. Furthermore, sufficient conditions on absolute stability for discrete Lur’e systems with norm and structured uncertainties are also presented based on linear matrix inequalities. Estimates of the maximum bounds of all admissible perturbations are given by generalized eigenvalue problems. Finally, several numerical examples are worked out to illustrate the efficiency of the main results.     

考虑随机需求及返回策略的供应链协调分析

在随机需求情形下,通过返回策略工具,运用Stackelberg非合作博弈理论,分别构建了多供应链竞争下,处于竞争劣势的分散式、集中式及收益共享情形下的供应链EOQ和供应链内部协调机制。供应链协调时,收益共享及集中式供应链EOQ、整体利润均大于分散式供应链的情形。相比分散式供应链情形,收益共享协调机制对供应链整体比较有利,对零售商最为有利。通过选择恰当共享系数,使返回策略与收益共享契约密切结合,可以有效降低产品的缺货、剩余及返回数量,进而提高零售商EOQ,较大幅度扩大市场销售份额,使供应链的整体收益大于集中式供应链的收益,并同时使供应链内部各成员的收益更加均衡,这为供应链的长期稳定发展奠定了坚实的基础。     

加强国际合作 实现跨越发展

能源问题是人类可持续发展的战略问题。大量科学探索证明,无限的聚变能将是人类最理想、最清洁、最安全的新能源。等离子体物理研究所(下称等离子体所)主要从事高温等离子体物理和受控热核聚变及相关高技术研究,以探索、开发、解决人类洁净的新能源为最终目的。在探索新能源的过程中,等离子体所通过广泛深入的国际合作,取得了显著成效。HT-7超导托卡马克装置实验取得重大突破,等离子体放电时间长达63.95秒,为未来聚变反应堆做出了中国聚变界的重要贡献。在聚变能的开发研究中,目前磁约束核聚变研究已处于世界领先地位。正在建设的国家大科…     

沉积微相约束条件下的随机地质建模方法及应用研究

以地质建模为主要研究对象,根据油田开发地质研究需要完善的方法技术,以建模方法研究为基础,进行了沉积微相约束地质建模综合研究.在分析目前国内外研究现状的基础上,针对我国开发地质研究工作的特点,提出根据测井解释成果,应用随机模拟的方法定量地开展沉积微相研究.应用沉积微相研究成果约束测井储层参数的分布,形成油藏数值模拟研究所需要的准确的储层三维地质模型,解决了常规油田开发地质研究过程中沉积相研究成果与储层参数分布无法有效结合的缺陷.应用与该方法相适应的IRMS软件成功实现了山东胜利油区孤东油田第七开发区西部上第三系馆陶组油藏精确的沉积微相模型,由此微相约束形成的油藏储层三维地质模型数据体直接应用于油藏数值模拟研究,应用效果及现场实施的效果良好.     

Robust bounds for fractional-order systems with uncertain order and structured perturbations via Cylindrical Algebraic Decomposition method

This paper considers the robust stability problem of fractional-order systems with uncertain order and structured perturbations. A stability check procedure is proposed for determining the robust bounds of uncertain order and other uncertain parameters for fractional-order systems.The results are obtained in terms of Cylindrical Algebraic Decomposition which is first used for analyzing the robust stability problem of fractional-order systems with uncertain order. The method is non-conservative for fractional-order systems with the uncertain order α satisfying 0?<?α?<?2. Examples are given to demonstrate the effectiveness of proposed approach.