Search

Constructing heterojunction is an attractive strategy for promoting photoelectrochemical (PEC) performance in water splitting and organic pollutant degradation. Herein, a novel porous BiVO

In this paper, a novel high dynamic range (HDR) image zero-watermarking algorithm against the tone mapping attack is proposed. In order to extract stable and invariant features for robust zero-watermarking, the shift-invariant shearlet transform (SIST) is used to transform the HDR image. Firstly, the HDR image is converted to CIELAB color space, and the L component is selected to perform SIST for obtaining the low-frequency subband containing the robust structure information of the image. Secondly, the low-frequency subband is divided into nonoverlapping blocks, which are transformed by using discrete cosine transform (DCT) and singular value decomposition (SVD) to obtain the maximum singular values for constructing a binary feature image. To increase the watermarking security, a hybrid chaotic mapping (HCM) is employed to get the scrambled watermark. Finally, an exclusive-or operation is performed between the binary feature image and the scrambled watermark to compute robust zero-watermark. Experimental results show that the proposed algorithm has a good capability of resisting tone mapping and other image processing attacks.

With the purpose of investigating the effects of geometry parameters of CFJ (Coflow jet) device on the aerodynamic characteristics of the supercritical bacj airfoil used by a STOL transport, we have carried out a computational analysis of CFJ airfoil with different values of injection slot size and location under the low-speed condition. The results show that the lift coefficient decreases gradually with decreasing stall angle, when the injection slot size is increased. When α=8°, with increasing injection slot size, the velocity of blowing jet decreases with decreasing power consumption and increasing aerodynamic effectiveness. Further, with the injection slot shifted towards the downstream direction, the α value corresponding to the maximum effective lift-drag-ratio increases with increasing maximum lift coefficient.

The tumor microenvironment is closely related to the progression and immune escape of tumor cells. Tumor-infiltrating immune cells (TIICs) and immune-related genes (IRGs) are indispensable components of the tumor microenvironment and have been demonstrated to be highly valuable in determining the prognosis of multiple cancers. To elucidate the prognostic value of TIICs and IRGs in gastric cancer, we conducted a comprehensive analysis focusing on the abundances of 22 types of TIICs and differentially expressed IRGs based on a dataset from The Cancer Genome Atlas (TCGA). The results showed that great composition differences in TIICs and immune cell subfractions were associated with survival outcomes in different stages. Additionally, 29 hub genes were characterized from 345 differentially expressed IRGs and found to be significantly associated with survival outcomes. Then, an independent prognostic indicator based on ten IRGs was successfully constructed after multivariate adjustment for some clinical parameters. Further validation revealed that these hub IRGs could reflect the infiltration levels of immune cells. Thus, our results confirmed the clinical significance of TIICs and IRGs in gastric cancer and may establish a foundation for further exploring immune cell and gene targets for personalized treatment.

A radar cross section (RCS) gradient calculation approach based on the discrete adjoint equation of Maxwell integral equation is proposed. The adjoint method can obtain the gradients of all design ...

This paper presents a high dynamic range (HDR) image zero watermarking method based on dual tree complex wavelet transform (DT-CWT) and quaternion. In order to be against tone mapping (TM), DT-CWT is used to transform the three RGB color channels of the HDR image for obtaining the low-pass sub-bands, respectively, since DT-CWT can extract the contour of the HDR image and the contour change of the HDR image is small after TM. The HDR image provides a wide dynamic range, and thus, three-color channel correlations are higher than inner-relationships and the quaternion is used to consider three color channels as a whole to be transformed. Quaternion fast Fourier transform (QFFT) and quaternion singular value decomposition (QSVD) are utilized to decompose the HDR image for obtaining robust features, which is fused with a binary watermark to generate a zero watermark for copyright protection. Furthermore, the binary watermark is scrambled for the security by using the Arnold transform. Experimental results denote that the proposed zero-watermarking method is robust to TM and other image processing attacks, and can protect the HDR image efficiently.

This study aimed to investigate the biological effects of supplementation of bovine lactoferricin (BLFc) at the rate of 100 mg/kg/day (LF-1) or 200 mg/kg/day (LF-2) in lactating dairy goats. Dietary BLFc supplementation increased the concentration of lactoferrin (LF) in the milk and serum (p < 0.05) without affecting the feed intake. In the LF-1 group, serum Fe, total antioxidant (T-AOC), and immunoglobulin A (IgA) were increased (p < 0.05), while malondialdehyde (MDA) was decreased (p < 0.05). In the LF-2 group, ruminal fluid pH value was decreased (p < 0.05), and the composition of ruminal microflora on day 42 was more diversified. Firmicutes phylum in the LF-2 group was the most abundant phyla. In contrast, Bacteroidetes phylum in the control group and the LF-1 group were the most abundant. Lower milk somatic cell count and higher IgA were observed in the LF-1 group and the LF-2 group than those in the control group (p < 0.05). These results suggested beneficial effects of supplementation of 100 mg/kg/day BLFc on reducing the oxidative stress and altering diversity of ruminal microflora.

As an efficient uncertainty quantification (UQ) methodology for moment propagation and probability analysis of quantities of interest, polynomial chaos (PC) expansions have received broad and sustained attentions. However, the exponentially increasing cost of building PC representations with increasing dimension of uncertainty, i.e., the curse of dimensionality, seriously restricts the practical application of PC at the industrial level. Some efficient strategies applying adaptive basis selection algorithm for sparse optimization (or l 1 -minimization) of PC show great potential compared to the classical full PC. However, these strategies mainly focus on forward selection algorithms, which are incapable of correcting any error made by these algorithms. Hence, this paper develops a novel adaptive forward–backward selection (AFBS) algorithm for reconstructing sparse PC. The proposed algorithm by a reasonable combination of forward selection and adaptively backward elimination technique can efficiently correct mistakes made by earlier forward selection steps, which retains the most significant PC terms and discards redundant or insignificant ones. The accuracy of built PC metamodel is checked by a cross-validation procedure. As a consequence, the most significant PC terms are detected sequentially and corresponding PC coefficients are accurately recovered. It largely enhances the sparsity of PC and improves the prediction accuracy compared to the popular forward selection algorithms, e.g., least angle regressions (LARs). To validate the efficiency of the proposed algorithm, a complex analytical function with Gaussian distribution inputs and two challenging aerodynamic applications including a sonic boom propagation analysis considering atmospheric uncertainty and a natural-laminar-flow (NLF) airfoil computation under both geometrical and operational uncertainties are elaborated. With an in-depth comparison with some popular PC reconstruction methodologies, the performance of the devised AFBS method is assessed comprehensively. The results demonstrate that the proposed AFBS method can efficiently identify the significant PC contributions describing the problems, and reproduce sparser PC metamodel and more accurate UQ results than those classical full PC and LARs methods.

Mitigation of sonic boom to an acceptable stage is a key point for the next generation of supersonic transports. Meanwhile, designing a supersonic aircraft with an ideal ground signature is always the focus of research on sonic boom reduction. This paper presents an inverse design approach to optimize the near-field signature of an aircraft, making it close to the shaped ideal ground signature after the propagation in the atmosphere. Using the Proper Orthogonal Decomposition (POD) method, a guessed input of augmented Burgers equation is inversely achieved. By multiple POD iterations, the guessed ground signatures successively approach the target ground signature until the convergence criteria is reached. Finally, the corresponding equivalent area distribution is calculated from the optimal near-field signature through the classical Whitham F-function theory. To validate this method, an optimization example of Lockheed Martin 1021 is demonstrated. The modified configuration has a fully shaped ground signature and achieves a drop of perceived loudness by 7.94 PLdB. This improvement is achieved via shaping the original near-field signature into wiggles and damping it by atmospheric attenuation. At last, a non-physical ground signature is set as the target to test the robustness of this inverse design method and shows that this method is robust enough for various inputs. Keywords: Aeroacoustics, Augmented Burgers equation, Low boom configuration, Optimization, Supersonic aerodynamics

With the continuous development and widespread attention of electric propulsion technology in traditional transportation fields such as automobiles and trains, the distributed propeller propulsion technology applied to electric or hybrid electric medium and small scale aircrafts has become a new topic in aviation research. This paper presents a preliminary design scheme of a distributed propeller electric propulsion transport aircraft firstly. Then, based on Reynolds average N-S equations, combined with the SA turbulence model, and replaced the real distributed propellers with simplified disk model, the aerodynamic characteristics of the aircraft with and without slipstream under the condition of low speed and high thrust at low altitude are analyzed. Finally, the effects of pressure distribution, pitching moment characteristics and wing flow on distributed propellers are studied in detailed. The results show that the lift and drag of the aircraft with slipstream are both larger than without slipstream and with slipstream effect, the pitching moment of the wing decreases, the pitching moment of the tail increases. When the tail is far away or completely inside the region of slipstream, the difference of pitching moment of the tail with and without slipstream is little, and the difference is obvious as the tail is only partially in the region of slipstream; When the diameter of distributed propellers is far larger than the wing thickness, more propeller power is used to shove air flow away from the surface area of the wing, and resulting in an insignificant increase in the coefficient of lift.

Dual carbon shells coated SnO2 hollow nanospheres (C@SnO2@C) are synthesized as anode material for lithium ion batteries, it delivers an almost constant capacity about 712.6 mAh g−1 after 300th cycles at 200 mA g−1. A capacity recovery (more than 200%) is observed during the high rate (5 A g−1) long cycling process (10000 cycles). The discharge capacity of the C@SnO2@C electrode is only 194.5 mAh g−1 after 200 cycles. Afterwards the capacity increases gradually until the 3000th cycle up to 500 mAh g−1 and then keeps stable for the subsequent cycles without obvious capacity fading tendency after 10000 cycles. These superior electrochemical performances should be attributed to the synergistic effect between the double carbon coating layers and the refined nanosized SnO2 nanocrystals. The double carbon coating layer could not only effectively provide buffers against the structural pulverization of electrodes during charge and discharge process through a novel spatial confinement strategy, but also facilitate the diffusion of electrons by enhancing the electronic conductivity. Thus, these benefits from the dually coated structure are able to provide a robust architecture for lithium-ion battery anodes.

The tumor immune microenvironment is of crucial importance in cancer progression and anticancer immune responses. Thus, systematic exploration of the expression landscape and prognostic significance of immune-related genes (IRGs) to assist in the prognosis of colon cancer is valuable and significant. The transcriptomic data of 470 colon cancer patients were obtained from The Cancer Genome Atlas database and the differentially expressed genes were analyzed. After an intersection analysis, the hub IRGs were identified and a prognostic index was further developed using multivariable Cox analysis. In addition, the discriminatory ability and prognostic significance of the constructed model were validated and the characteristics of IRGs associated overall survival were analyzed to elucidate the underlying molecular mechanisms. A total of 465 differentially expressed IRGs and 130 survival-associated IRGs were screened. Then, 46 hub IRGs were identified by an intersection analysis. A regulatory network displayed that most of these genes were unfavorable for the prognosis of colon cancer and were regulated by transcription factors. After a least absolute shrinkage and selection operator regression analysis, 14 hub IRGs were ultimately chose to construct a prognostic index. The validation results illustrated that this model could act as an independent indicator to moderately separate colon cancer patients into low- and high-risk groups. This study ascertained the prognostic significance of IRGs in colon cancer and successfully constructed an IRG-based prognostic signature for clinical prediction. Our results provide promising insight for the exploration of diagnostic markers and immunotherapeutic targets in colon cancer.

An electrolyte cation additive strategy provides a versatile route for developing high-energy and long-life aqueous zinc-ion hybrid capacitors. However, the mechanisms of energy storage and Zn anode protection are still unclear in Zn-based systems with dual-ion electrolytes. Here, a dual charge storage mechanism for zinc-ion hybrid capacitors with both cations and anions adsorption/desorption and the reversible formation of Zn4SO4(OH)6·xH2O enabled by the Mg2+ additive in the common aqueous ZnSO4 electrolyte are proposed. Theoretical calculations verify that the self-healing electrostatic shield effect and the solvation-sheath structure regulation rendered by the Mg2+ additive account for the observed uniform Zn deposition and dendrite suppression. As a result, an additional energy storage capacity of ≈50% compared to that in a pure 2 m ZnSO4 electrolyte and an extended cycle life with capacity retention of 98.7% after 10 000 cycles are achieved. This work highlights the effectiveness of electrolyte design for dual-ion carrier storage mechanism in aqueous devices toward high energy density and long cycle life. Ministry of Education (MOE) Submitted/Accepted version This work was supported by the National Natural Science Foundation of China (Grant Nos. 51972346, 51932011), the Hunan Natural Science Fund for Distinguished Young Scholar (2021JJ1006), the Program of Youth Talent Support for Hunan Province (2020RC3011), the Innovation-Driven Project of Central South University (No. 2020CX024), and the Fundamental Research Funds for the Central Universities of Central South University (No. 202321024). H.J.F acknowledges the financial support from Ministry of Education by Tier 1 grant (RG85/20).

The trans-10,cis-12 isomer of conjugated linoleic acid (t10c12-CLA) is a biohydrogenation intermediate in the rumen and has been shown to cause milk fat depression in dairy goats. However, few studies have focused on the in vitro molecular mechanisms involved in the response of the goat mammary gland to t10c12-CLA. In the present study, RNA sequencing technology was used to investigate the effects of t10c12-CLA on goat mammary epithelial cells. From the data, 25,153 annotated transcripts were obtained, and differentially expressed genes were selected based on a false discovery rate

Rudder Lock is a threat to flight safety, which should be carefully considered in the airworthiness certification. Since general aircrafts which are equipped with mechanical control system and controlled by unprofessional pilots becomes more and more popular, researches on rudder lock are still necessary. In this paper, a mechanically controlled medium sized transport is studied as an example. By analyzing the steady straight sideslip flight test data and flow field numerical simulation results, the mechanism of rudder lock is analyzed. Two aerodynamic improving methods including double-triangle dorsal fin and reducing set-back hinge balance are proposed. The flow field numerical simulation results show that double triangle dorsal fin can improve the stall characteristic of vertical tail, but the strong vortex will move the center of pressure forward, which worsens the rudder lock. Reducing set-back hinge balance can improve rudder lock effectively, while the hinge moment and rudder force will be increased, therefore the gearing ratio and tab should be carefully designed.

Lactoferrin (LF) is a prominent protein in milk, and is present in many other secretory fluids and white blood cells. The variation of LF content in milk is possibly regulated by multiple environmental factors such as milk composition and endogenous factors. In this study, we analysed the variations of LF in both milk and plasma of 20 Xinong Saanen goats and its related factors. Firstly, LF content in colostrum was 222.6 ± 41.57 μg/mL, and then throughout the lactation period the mean concentrations remained stable, ranged between 34.61 and 51.94 μg/mL. The LF concentration in plasma fluctuated between 173.56 and 246.20 μg/mL during the entire lactational period. There was no correlation between the milk and plasma LF concentrations (P > .05). However, LF in milk was closely correlated with milk lactose, protein and SNF contents (P .05). In addition, LF concentration in milk was correlated with the lactation stage (P

GPS data often have position deviations in precision and are apt to be affected by noise; hence, it is essential to extract features from trajectories before performing large-scale data mining. A GeoHash-based spatial coding technique called GeoHashTree was used to index spatiotemporal trajectory points in order to improve the efficiency of nearest-neighbor search. The GeoHashTree was applied in trajectory clustering and an improved density-based clustering algorithm was proposed to reduce the time complexity of nearest-neighbor search from $O(n^2)$ to $O(n\\log{n})$. After extracting trajectory points with changing angles, the proposed clustering approach was employed to achieve deep-level feature extraction on trajectory points with changing angles, which aims to accurately identify feature points. Extensive experiments are conducted on real GPS data and the results demonstrate that the proposed trajectory-clustering algorithm based on the GeoHashTree spatial index structure can improve time performance by an average of 90.89% as well as guarantee the accuracy of clustering compared with the traditional clustering method. The visualization results show that the trajectory feature extraction approach can effectively find trajectory points with changing angles and discover a varying types of feature points from large-scale data sets. In addition, the proposed approach does not depend on road network data and can dynamically update with new incoming trajectory data as road networks change in real time.

Based on improved multi-objective particle swarm optimization (MOPSO) algorithm with principal component analysis (PCA) methodology, an efficient high-dimension multi-objective optimization method is proposed, which, as the purpose of this paper, aims to improve the convergence of Pareto front in multi-objective optimization design. The mathematical efficiency, the physical reasonableness and the reliability in dealing with redundant objectives of PCA are verified by typical DTLZ5 test function and multi-objective correlation analysis of supercritical airfoil, and the proposed method is integrated into aircraft multi-disciplinary design (AMDEsign) platform, which contains aerodynamics, stealth and structure weight analysis and optimization module. Then the proposed method is used for the multi-point integrated aerodynamic optimization of a wide-body passenger aircraft, in which the redundant objectives identified by PCA are transformed to optimization constraints, and several design methods are compared. The design results illustrate that the strategy used in this paper is sufficient and multi-point design requirements of the passenger aircraft are reached. The visualization level of non-dominant Pareto set is improved by effectively reducing the dimension without losing the primary feature of the problem.

Rotor airfoil design is investigated in this paper. There are many difficulties for this high-dimensional multi-objective problem when traditional multi-objective optimization methods are used. Therefore, a multi-layer hierarchical constraint method is proposed by coupling principal component analysis (PCA) dimensionality reduction and e-constraint method to translate the original high-dimensional problem into a bi-objective problem. This paper selects the main design objectives by conducting PCA to the preliminary solution of original problem with consideration of the priority of design objectives. According to the e-constraint method, the design model is established by treating the two top-ranking design goals as objective and others as variable constraints. A series of bi-objective Pareto curves will be obtained by changing the variable constraints, and the favorable solution can be obtained by analyzing Pareto curve spectrum. This method is applied to the rotor airfoil design and makes great improvement in aerodynamic performance. It is shown that the method is convenient and efficient, beyond which, it facilitates decision-making of the high-dimensional multi-objective engineering problem.

Tree peony (Paeonia Sect. Moutan) is a famous ornamental plant, with huge historical, cultural, and economic significance worldwide. In this study, we reported the ~13.79 Gb draft genome of a wide‐grown Paeonia suffruticosa cultivar “Luo shen xiao chun,” representing the largest sequenced genome in dicots to date. Phylogenetic analyses based on genome sequences demonstrated that P. suffruticosa was placed as sister to Vitales, and they together formed a clade that was sister to Rosids, weakly supporting a relationship of ((Saxifragales and Vitales) and Rosids). The identification and expression analysis of MADS‐box genes based on the genome assembly and de novo transcriptome assembly of P. suffruticosa revealed that the function of C class genes was restricted in flower development, which might be responsible for the stamen petalody in tree peony cultivars. Overall, the first sequenced genome in the family Paeoniaceae provides an important resource for the origin, domestication, and evolutionary study as well as cultivar breeding in tree peony., Tree peony (Paeonia Sect. Moutan) is a famous ornamental plant, with huge historical, cultural, and economic significance worldwide. The presented genome assembly in this study would serve as an important resource for functional genomic and genetic studies on tree peony, which would be useful for the conservation of endangered wild paeonia species and exploring the mechanisms of plant diversification and adaption under domestication in various environments.

Silicon is regarded as the most promising candidate for the next-generation anode materials, because of its high specific capacity and wide availability. However, silicon anode materials suffer from large volume change during the charging/discharging processes, which leads to a too fast capacity degradation. To alleviate the volume change and capacity degradation, preforming pore structure in silicon anode materials is the most frequently adopted strategy. The pores are usually formed either by using templates or through selective etching, which involves complicated preparation process and consumes hazard chemicals. Here, we propose a nanostructured silicon anode derived from low-cost raw materials without the use of templates. The composite is composed of dense active cores and fluffy cocoon-like buffer layer. The buffer layer is a network of carbon nanobelts, which accommodates the volume change and maintains the electrical contact during the charging/discharging processes. As a result, the porous composite with the buffer layer displays a high cyclability, with a capacity retention of 104% after 100 cycles, while the dense sample without the buffer layer has a capacity retention of only 36%. Moreover, the process is green, effective and scalable, which could promote the application of silicon based anode materials.

In situ characterization techniques have made a significant progress in recent years, especially in the electrochemical field. For Li-ion batteries, in situ characterization techniques refer to using analytical equipment to directly characterize electrode materials during electrochemical measurements. At present, most in situ batteries are developed from commercial simulated batteries, of which the cost is very high and the cycle life is quite short. In this work, two kinds of coin-cell-based in situ batteries were designed as in situ X-ray diffraction (XRD) and Raman coin cells which exhibit many admirable advantages, such as low cost, long cycle life, easy to carry, and so on. In the designing process, in situ XRD and Raman coin cell have been tested with two electrode materials of Li4Ti5O12 and LiFePO4, and we solved many technical problems of assembling and measuring these two kinds of cells. Finally, in situ coin cells could be improved to investigate a variety of electrode materials, and this technique would arouse wide interests in the electrochemical field.

Experiment design method is a key to construct a highly reliable surrogate model for numerical optimization in large-scale project. Within the method, the experimental design criterion directly affects the accuracy of the surrogate model and the optimization efficient. According to the shortcomings of the traditional experimental design, an improved adaptive sampling method is proposed in this paper. The surrogate model is firstly constructed by basic sparse samples. Then the supplementary sampling position is detected according to the specified criteria, which introduces the energy function and curvature sampling criteria based on radial basis function (RBF) network. Sampling detection criteria considers both the uniformity of sample distribution and the description of hypersurface curvature so as to significantly improve the prediction accuracy of the surrogate model with much less samples. For the surrogate model constructed with sparse samples, the sample uniformity is an important factor to the interpolation accuracy in the initial stage of adaptive sampling and surrogate model training. Along with the improvement of uniformity, the curvature description of objective function surface gradually becomes more important. In consideration of these issues, crowdness enhance function and root mean square error (RMSE) feedback function are introduced in C criterion expression. Thus, a new sampling method called RMSE and crowdness enhance (RCE) adaptive sampling is established. The validity of RCE adaptive sampling method is studied through typical test function firstly and then the airfoil/wing aerodynamic optimization design problem, which has high-dimensional design space. The results show that RCE adaptive sampling method not only reduces the requirement for the number of samples, but also effectively improves the prediction accuracy of the surrogate model, which has a broad prospects for applications.

Quality and robustness of grid deformation is of the most importance in the field of aircraft design, and grid in high quality is essential for improving the precision of numerical simulation. In order to maintain the orthogonality of deformed grid, the displacement of grid points is divided into rotational and translational parts in this paper, and inverse distance weighted interpolation is used to transfer the changing location from boundary grid to the spatial grid. Moreover, the deformation of rotational part is implemented in combination with the exponential space mapping that improves the certainty and stability of quaternion interpolation. Furthermore, the new grid deformation technique named “layering blend deformation” is built based on the basic quaternion technique, which combines the layering arithmetic with transfinite interpolation (TFI) technique. Then the proposed technique is applied in the movement of airfoil, parametric modeling, and the deformation of complex configuration, in which the robustness of grid quality is tested. The results show that the new method has the capacity to deal with the problems with large deformation, and the “layering blend deformation” improves the efficiency and quality of the basic quaternion deformation method significantly.

A transonic, high Reynolds number natural laminar flow airfoil is designed and studied. The γ-θ transition model is combined with the shear stress transport (SST) k-w turbulence model to predict the transition region for a laminar-turbulent boundary layer. The non-uniform free-form deformation (NFFD) method based on the non-uniform rational B-spline (NURBS) basis function is introduced to the airfoil parameterization. The non-dominated sorting genetic algorithm-II (NSGA-II) is used as the search algorithm, and the surrogate model based on the Kriging models is introduced to improve the efficiency of the optimization system. The optimization system is set up based on the above technologies, and the robust design about the uncertainty of the Mach number is carried out for NASA0412 airfoil. The optimized airfoil is analyzed and compared with the original airfoil. The results show that natural laminar flow can be achieved on a supercritical airfoil to improve the aerodynamic characteristic of airfoils.

Correction for ‘Memory-effect-induced electrochemical oscillation of an Al-doped Li4Ti5O12 composite in Li-ion batteries’ by Liao Zhang et al., Chem. Commun., 2019, 55, 1279–1282.