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Gene selection is an indispensable step for analyzing noisy and high-dimensional single-cell RNA-seq (scRNA-seq) data. Compared with the commonly used variance-based methods, by mimicking the human maker selection in the 2D visualization of cells, a new feature selection method called HRG (Highly Regional Genes) is proposed to find the informative genes, which show regional expression patterns in the cell-cell similarity network. We mathematically find the optimal expression patterns that can maximize the proposed scoring function. In comparison with several unsupervised methods, HRG shows high accuracy and robustness, and can increase the performance of downstream cell clustering and gene correlation analysis. Also, it is applicable for selecting informative genes of sequencing-based spatial transcriptomic data.

Two types of Y2O3 partially stabilized ZrO2(YSZ)-based agglomerated powders with and without SiC whiskers were prepared by spray granulation, and the flow ability, apparent density and particle size distribution of them were investigated. The thermal cycling performance and failure mechanism of conventional high temperature sealing coating and modified one with additional layer with whiskers, which were sprayed by air plasma spraying (APS), were comparatively analyzed. The results showed that, compared to the powder without whiskers, the flow ability of that with whiskers reduced by 2.32%, and the apparent density and the proportion of 45–150 μm agglomerated powder increased by 1.53% and 2.29%, respectively. The thermal cycling failure mode of conventional high temperature sealing coating was the overall spalling of ceramic coating, and the spalling position originated from the interface of thermally grown oxide (TGO)/ceramic coating. Microstructure observation indicated that the structure integrity of SiC whiskers in the additional layer sprayed by APS was still retained. The whiskers were uniformly distributed and the interfaces between bonding coating and ceramic coating exhibited excellent bonding. With the additional layer containing whiskers, the thermal cycling life of the coating was increased by 102.53%. In the thermal cycling process, the “bridging” and “pulling-out” effects of whiskers located at the additional layer consumed considerable energy, which could reduce the driving force of crack growth. Besides, a porous structure of the additional layer after thermal cycling was formed due to “bridging” and “pulling-out” of whiskers, further improving the thermal cycling life of coating with the additional layers.

For the case that two pursuers intercept an evasive target, the cooperative strategies and state estimation methods taken by pursuers can seriously affect the guidance accuracy for the target, which performs a bang For the case that two pursuers intercept an evasive target, the cooperative strategies and state estimation methods taken by pursuers can seriously affect the guidance accuracy for the target, which performs a bang-bang evasive maneuver with a random switching time. Combined Fast multiple model adaptive estimation (Fast MMAE) algorithm, the cooperative guidance law takes detection configuration affecting the accuracy of interception into consideration. Introduced the detection error model related to the line-of-sight (LOS) separation angle of two interceptors, an optimal cooperative guidance law solving the optimization problem is designed to modulate the LOS separation angle to reduce the estimation error and improve the interception performance. Due to the uncertainty of the target bang-bang maneuver switching time and the effective fitting of its multi-modal motion, Fast MMAE is introduced to identify its maneuver switching time and estimate the acceleration of the target to track and intercept the target accurately. The designed cooperative optimal guidance law with Fast MMAE has better estimation ability and interception performance than the traditional guidance law and estimation method via Monte Carlo simulation.

Process intensification in rotating packed bed (RPB) has been demonstrated to be a favorite and spotlight in field of multiphase transportation and reaction. The state of the art in the field of mass transfer has been investigated and proposed. In this review, firstly, highlighted modifications on rotor and distributor are developed and enumerated to inspire the potential on mass transfer. Additionally, various methods are presented and compared based on their adaptation. Then, much effort has been directed at analyses below: Characteristics of flow are qualitative in flow distribution while characteristics of mass transfer are quantitative in correlations and parameters. Finally, applications which are excellent in mass transfer among conventional chemical industry and emerging industry are described. The review mentions the considerable opportunity for exploitation of hybrid technology in mass transfer and highlights the valuable challenge in multidisciplinary integration. To inspire the potential on mass transfer process in RPB, fundamental research on structures, methods, characteristics and applications are also prospective.

In the present study, an optimal laminar flow minichannel heat sink (MCHS) has been determined through three-dimensional simulations and the multi-objective optimization algorithm. The cross-sectional shape described by six variables is optimized by the multi-objective genetic algorithm (MOGA) and multi-objective particle swarm optimization (MOPSO). During the optimization, the thermal resistance θ and pumping power P are two conflicting objectives for evaluating the performances of the MCHS. After obtaining the non-inferior solutions, the technique for order preference by similarity to an ideal solution (TOPSIS) is applied as a decision-making method to determine the best compromise one. Results indicate that the TOPSIS can effectively reduce the P of the Pareto solutions without significantly increasing θ. Compared with the straight channel, the TOPSIS optimal solution could reduce θ by 7.47% or P by 31.54%. Meanwhile, the mechanism of performance improvement is analyzed by comparing the TOPSIS optimal solution and the straight channel with the same P. It is observed that the optimized channel shape changes the fluid distribution by increasing the heat transfer coefficient slightly and the heat transfer area by 12.22%, respectively.

Hepatocellular carcinoma (HCC) is highly heterogeneous in nature and has been one of the most common cancer types worldwide. To ensure repeatability of identified gene expression patterns and comprehensively annotate the transcriptomes of HCC, we carefully curated 15 public HCC expression datasets that cover around 4000 clinical samples and developed the database HCCDB to serve as a one-stop online resource for exploring HCC gene expression with user-friendly interfaces. The global differential gene expression landscape of HCC was established by analyzing the consistently differentially expressed genes across multiple datasets. Moreover, a 4D metric was proposed to fully characterize the expression pattern of each gene by integrating data from The Cancer Genome Atlas (TCGA) and Genotype-Tissue Expression (GTEx). To facilitate a comprehensive understanding of gene expression patterns in HCC, HCCDB also provides links to third-party databases on drug, proteomics, and literatures, and graphically displays the results from computational analyses, including differential expression analysis, tissue-specific and tumor-specific expression analysis, survival analysis, and co-expression analysis. HCCDB is freely accessible at http://lifeome.net/database/hccdb. Keywords: Hepatocellular carcinoma, Database, Transcriptome, Integrative analysis, Meta-analysis

Today, the use of alternative energy sources such as solar energy to overcome the obstacles caused by the consumption of fossil fuels is inevitable. However, solar energy faces natural issues such as intermittency, instability and uncertainty. Meanwhile, integration of clean energy sources can be a key solution. On the other hand, fuel cells are conversion devices that have advantages, e.g., high reliability, low emissions, and high efficiency. The aim of this study is to present and evaluate the operation of a new energy process based on alkaline fuel cell (AFC) and solar photovoltaic (PV) field. AFC produces electrical and thermal power. In downstream cycles, additional electricity and cooling are generated by the Stirling engine and the absorption chiller, respectively. The solar field provides the power of an electrolyzer to supply fuel and oxidant to the fuel cell. Results showed that the cycle can produce up to 3.4 kW of electricity. The share of AFC, Stirling engine and solar PV field in electricity generation is 29.3, 21.4 and 49.3 %, respectively. It was also found that the electrical and overall efficiencies of the cycle are 64.36 and 77.57 %, respectively. In addition, 77.44 kW of exergy is destroyed.

Distributed array antenna synthetic aperture radar (SAR), flexible baseline interferometric SAR (InSAR) or integrated multi-task imaging sensors are the most attractive development directions of aerial survey and remote sensing system, and urgently demand a distributed Position and Orientation System (DPOS) to accurately measure multi-nodes time-spatial reference information. However, the traditional transfer alignment (TA) method can't meet the requirements of some high precision interferometric imaging task. To solve the problem, a dual-filter TA method based on position-velocity-attitude matching (PVAM) was proposed. Firstly, the TA method based on attitude matching (AM) is conducted in filter-1 to estimate the flexible angles and the derivatives. Then the TA method based on position-velocity matching (PVM) is conducted in filter-2, and the position and velocity measurements are compensated by the flexible angles and the derivatives estimated by filter-1. Finally, the strapdown solutions of slave IMU are corrected by the corrections from both filter-1 and filter-2. A semi-physical simulation based on airborne DPOS flight experiment has been conducted, verifying that the baseline error has been reduced from 0.0240 m to 0.0083 m and the computation time has been decrease by 3.41%.

We present a 3-manifold automorphism f : M → M with rank Fix ( f ⁎ ) = 2 rank π 1 ( M ) . Related facts are discussed.

Nuclear power has gradually become one of the key parts in power supply structure due to its environmental benefits, effective productivity and steady operation. However, complicated system, high investment and derivative security issues make it difficult to develop in a large scale. Nowadays, faced with serious challenges from environment protection, fossil fuel lacking and upgrading of industrial structure, China are taking measures to promote nuclear power industry to realize sustainable development. China׳s nuclear power industry has achieved large achievements in industrial policy, technical and economic condition during the last three decades. However, there still exist problems impeding its future development. Therefore, this paper first analyzes the external environment and historical stages of nuclear power industry in China. Then, it summarizes its current situation and points out the existing problems. In the end, to deal with the above problems, this paper proposes relative solutions from the aspects of industrial distribution optimization, regional resources integration, technical standard system, industrial organization mode and so on.

Automatic target recognition in infrared imagery is a challenging problem. In this paper, a kernel sparse coding method for infrared target recognition using covariance descriptor is proposed. First, covariance descriptor combining gray intensity and gradient information of the infrared target is extracted as a feature representation. Then, due to the reason that covariance descriptor lies in non-Euclidean manifold, kernel sparse coding theory is used to solve this problem. We verify the efficacy of the proposed algorithm in terms of the confusion matrices on the real images consisting of seven categories of infrared vehicle targets.

In this paper, numerical simulation has been carried out to study effect of heater power allocation on the thermal stress evolution during Kyropoulos sapphire cooling process. Characteristics of the temperature and stress distributions during the whole cooling process are firstly analyzed. A design of divided side heater is then proposed for a flexible power adjustment. The transient profiles of thermal stresses are obtained from analysis of the typical power allocation ratios of the top part to the lower part of the side heater. The results show that during the cooling process large stresses usually present in the regions near the ‘throat’ and ‘bottleneck’ of the crystal. The highest stress turns up at the bottleneck during the naturally cooling process occurred after the power is off. The results further indicate that the von Mises stress significantly decreases as the power radio increases. Additionally, the maximum stresses for a higher power ratio under the range of the current study are always smaller than that of a lower one before reaching the peak values, which is beneficial to avoid thermal stress-related defects. Based on the analysis, optimized power allocation of the side heater is recommended.

In this paper, the influence of the slot parameters of the slotted fins on the flow and heat transfer performance and the exergy destruction are studied by numerical simulation, and the optimal parameters corresponding to the best overall performance and the minimum exergy destruction are obtained by the method of CFD coupled with optimization algorithm, respectively. In current work, the slot length and width are taken as parameters (slot length 1.2–2.1 mm, slot width 0.1–1.0 mm), 100 different cases are studied under the same boundary conditions, and the results are analyzed and optimized by the neural network and genetic algorithm. The overall performance is taken as the evaluation of the heat transfer performance and the power consumption, while exergy destruction caused by heat transfer and fluid flow are taken as the estimate of the loss of available energy and mechanical work. The results show that the overall performance is best when the slot length and width are 1.38 mm and 0.27 mm respectively, and the overall performance is 13.1% higher than that of flat fin. While the exergy destruction caused by heat transfer and fluid flow are minimized synergistically when the slot length and width are 1.37 mm and 0.12 mm, and the irreversible loss caused by heat transfer is reduced by 19.13%, at the cost of an increase of 40.6% in the irreversible loss caused by fluid flow. The difference between the parameters corresponding to best overall performance and exergy destruction minimization means the irreversible loss of heat transfer and fluid flow process is not minimum when the overall performance is best, and indicates the exergy destruction minimization can be a principle to evaluate the heat transfer and flow process. The result in this paper is of great significant to the energy utilization and the improvement of the thermal quality in waste heat recovery.

In this paper, we study the consensus problem of multi-agent systems with parametric uncertainties on directed graph communication topologies containing a spanning tree. The challenge lies in that the input–output property of a strictly proper system transfer function involving self and communication delays and the extremum of a delay-involved transfer function are both unclear. By establishing a new input–output property of the delay-involved strictly proper transfer function and applying a constructive approach in frequency domain, we obtain the extremum of the delay-involved transfer function, upon which, we establish a unified framework to resolve the consensus problem of multi-agent systems with parametric uncertainties and time delays, and the terminal convergence point value is achieved. Based upon Lyapunov stability theory and frequency domain input–output analysis, we demonstrate that the proposed unified consensus control framework ensures scaled weighted average consensus with the integral action of the synchronization signal vector. Simulation results are provided to demonstrate the effectiveness of the proposed consensus scheme.

Small target detection in infrared video sequence is a challenging problem. In this paper, a collaborative structured sparse coding (SSC) model which incorporates the L 1 , 2 and L 2 , 1 regularization terms is proposed. The Alternating Direction Method of Multiplier (ADMM) is developed to solve this model. Further, online dictionary learning is embedded into the model and temporal information is incorporated to eliminate the clutters and noises. Extensive synthetic and real data experiments show that our method obtains better detection performance than baseline methods and state-of-art infrared-patch-image (IPI) model.

In this paper, the theoretical and practical feasibility of estimating ego-motion in monocular navigation is under investigation. In particular, this paper concerns the observability issues of monocular navigation models. In order to recover the ego-motion of the monocular camera from 2D (two-dimension) image sequence, this paper proposes a novel recursive parametric model. This model differs from other traditional parametric models with the reduced state-dimension and the consistent observability of system state. In addition, the consistent observability of different models are compared by using time-varying observability analysis theory. At the end of this paper, two groups of experiments are implemented to validate the effectiveness of the proposed method.

The paper presents linear system Input–Output Finite-Time Stabilization (IO-FTS) method under Finite-Time Boundedness (FTB) constraint. A state feedback controller is designed, via Linear Matrix Inequalities (LMIs), to guarantee the system both IO-FTS and FTB. The proposed methods are applied to the guidance design of a class of terminal guidance systems to suppress disturbances with IO-FTS method and FTB constraints simultaneously satisfied. The simulation results illustrate the effectiveness of the proposed methods.

In this paper, we consider the consensus problem of multiple agents modeled by Euler–Lagrange (EL) equation, among which two classes of agents are addressed, i.e., some agents with exactly known parameters and the others with parametric uncertainties. We propose a distributed consensus protocol for the heterogeneous EL systems in which both time-delay and jointly connected topologies are taken into consideration. Based on graph theory, Lyapunov theory and Barbalat׳s lemma, the stability of the controller is proved. A distinctive feature of this work is to investigate the consensus problem of EL systems with heterogeneous dynamics, time-delay and jointly connected topologies in a unified theoretical framework. Simulation results are also provided to illustrate the effectiveness of the obtained results.

In this paper, we consider the consensus problem of a class of heterogeneous multi-agent systems composed of the linear first-order and second-order integrator agents together with the nonlinear Euler–Lagrange (EL) agents. First, we propose a distributed consensus protocol under the assumption that the parameters of heterogeneous system are exactly known. Sufficient conditions for consensus are presented and the consensus protocol accounting for actuator saturation is developed. Then, by combining adaptive controller and PD controller together, we design a protocol for the heterogeneous system with unknown parameters (in the nonlinear EL dynamics). Based on graph theory, Lyapunov theory and Barbalat's Lemma, the stability of the controllers is proved. Simulation results are also provided to illustrate the effectiveness of the obtained results.

This paper studies the adaptive consensus problem of networked mechanical systems with time-varying delay and jointly-connected topologies. Two different consensus protocols are proposed. First, we present an adaptive consensus protocol for the connected switching topologies. Based on graph theory, Lyapunov stability theory and switching control theory, the stability of the proposed algorithm is demonstrated. Then we investigate the problem under the more general jointly-connected topologies, and with concurrent time-varying communication delay. The proposed consensus protocol consists of two parts: one is for the connected agents which contains the current states disagreement among them and the other is designed for the isolated agents which contains the states difference between the current and past. A distinctive feature of this work is to address the consensus control problem of mechanical systems with unknown parameters, time-varying delay and switching topologies in a unified theoretical framework. Numerical simulation is provided to demonstrate the effectiveness of the obtained results.

Real-time and accurate fault detection is essential to enhance the aircraft navigation system’s reliability and safety. The existent detection methods based on analytical model draws back at simultaneously detecting gradual and sudden faults. On account of this reason, we propose an online detection solution based on non-analytical model. In this article, the navigation system fault detection model is established based on belief rule base (BRB), where the system measuring residual and its changing rate are used as the inputs of BRB model and the fault detection function as the output. To overcome the drawbacks of current parameter optimization algorithms for BRB and achieve online update, a parameter recursive estimation algorithm is presented for online BRB detection model based on expectation maximization (EM) algorithm. Furthermore, the proposed method is verified by navigation experiment. Experimental results show that the proposed method is able to effectively realize online parameter evaluation in navigation system fault detection model. The output of the detection model can track the fault state very well, and the faults can be diagnosed in real time and accurately. In addition, the detection ability, especially in the probability of false detection, is superior to offline optimization method, and thus the system reliability has great improvement.

This paper studies adaptive attitude synchronization of spacecraft formation with possible time delay. By introducing a novel adaptive control architecture, decentralized controllers are developed, which allow for parameter uncertainties and unknown external disturbances. Based upon graph theory, Lyapunov stability theory and time-delay control theory, analytical tools are also provided. A distinctive feature of this work is to address the adaptive attitude synchronization with unknown parameters and coupling time delay in a unified theoretical framework, with general directed information flow. It is shown that arbitrary desired attitude tracking and synchronization with respect to a given reference can be attained. Simulation results are provided to demonstrate the effectiveness of the obtained results.

To solve the problem of interception avoidance of flight vehicle, this paper comprehensively considers miss distance, energy consumption and prediction uncertainty on the final time of interception by a finite-time H ∞ performance measure, and designs optimal energy consumption maneuver. An optimal interception against optimal evader maneuver of flight vehicle is also presented. The results show that the best evader effect will be achieved under condition of a large amplitude evader maneuver at the end of interception if the flight vehicle can predict the final time of interception accurately, and a large interception miss distance will be gained at a relatively small energy consumption.

Let M be a compact orientable 3-manifold, and let F be a separating (resp. non-separating) incompressible surface in M which cuts M into two 3-manifolds M1 and M2 (resp. a manifold M1). Then M is called the surface sum (resp. self surface sum) of M1 and M2 (resp. M1) along F, denoted by M=M1∪FM2 (resp. M=M1∪F). In this paper, we will study how g(M) is related to χ(F), g(M1) and g(M2) when both M1 and M2 have high distance Heegaard splittings.

We say a knot $k$ in the 3-sphere $\mathbb S^3$ has {\it Property $IE$} if the infinite cyclic cover of the knot exterior embeds into $\mathbb S^3$. Clearly all fibred knots have Property $IE$. There are infinitely many non-fibred knots with Property $IE$ and infinitely many non-fibred knots without property $IE$. Both kinds of examples are established here for the first time. Indeed we show that if a genus 1 non-fibred knot has Property $IE$, then its Alexander polynomial $\Delta_k(t)$ must be either 1 or $2t^2-5t+2$, and we give two infinite families of non-fibred genus 1 knots with Property $IE$ and having $\Delta_k(t)=1$ and $2t^2-5t+2$ respectively. Hence among genus one non-fibred knots, no alternating knot has Property $IE$, and there is only one knot with Property $IE$ up to ten crossings. We also give an obstruction to embedding infinite cyclic covers of a compact 3-manifold into any compact 3-manifold., Comment: 24 pages, 9 figures

We construct a class of simple, small knots in a handlebody of genus g , for any g >1.

Fission track study has been conducted on the miarolitic garnet from Zhangzhou Igneous Complex. It is found that the garnet is of Mn- and Fe-rich type; its uranium concentration ranges from 0.2 to 0.8 μg/g, with an average of 0.7 μg/g; fission track age of the garnet is 73.4±2.8 Ma; and induced fission track length and spontaneous fission track length are 11.5±0.7 μ m and 11.0±0.8 μ m, respectively. These data were used to constrain evolution of the granite body.

The etching characteristics of phosphate glass VG-13 have been studied in various etching conditions using relativistic heavy ions U-238, Au-197 and La-139. The addition of KF to HBF4 solution obviously increases the sensitivity of VG-13. The effects of concentration of KF on S and V(g) were studied. For La ions (z/beta=63), S was measured to be about 1.15.

For each closed hyperbolic (orientable or nonorientable) surface F, we provide a positive integer h(F) with properties that for any homeomorphism ƒ on F, at least one of the iterates ƒ,ƒ2,…,ƒh(F) has a fixed point and there is a periodic (orientation reversing) homeomorphism s on F such that s1, s2,…,sh(F)−1 are all fixed point free. Those integers h(F) are: h(F2) = 4, h(Fg) = 2g − 2, g>2, h(N3)= 2, h(Nq)= q − 2, q>3. There is an interesting difference between our result and the Nielsen's result in the orientable category.

In this paper, we determine the maximum orders of periodic maps on closed surfaces. For the orientable closed surface of genus g , g ⩾2, this maximum order is 4 g + 2 (realized by an orientation preserving map) if g is odd and is 4 g + 4 (realized by an orientation reversing map) otherwise. For the nonorientable closed surface of genus q , q ⩾3, this maximum order is 2 q if q is odd and is 2 q − 2 otherwise. Furthermore, the maximum order of orientation reversing periodic maps on F g is 4 g − 4 if g is odd.