改进的多光谱聚合通道行人检测

针对外部环境的多变性和复杂性导致的单一波段下行人检测准确率较低的问题,提出了一种改进的基于可见和红外双波段聚合通道特征的行人检测算法。分别提取可见图像与红外图像的聚合通道特征;通过改变像素对比规则,采用自适应的阈值进行比较,将得到的改进的中心对称的局部二值模式特征添加到特征通道中;针对多光谱聚合通道特征设计了不同滤波器组进行滤波;训练分类器,实现多光谱下行人检测。实验表明,改进的局部二值模式特征能更好地描述红外图像中行人的对称性,中间滤波层丰富了候选特征池,算法在多种场景均能有效检测出行人,提高了行人检测精度,与利用多光谱聚合积分通道的检测工作相比,平均漏检率有所降低。

Introducing tree neighbouring relationship factors in forest pattern spatial analysis:weighted Delaunay triangulation method

It is important to quantify and analyze forest spatial patterns for studying biological characteristics,population interaction and the relationship between the population and environment.In this study,the forest spatial structure unit was generated based on the Delaunay triangulation model(DTM),and the weights were generated using the comprehensive values of the tree diameter at breast height,total height and crown width.The distance between neighbors determined by the DTM was weighted to transform the original coordinates of trees into logical coordinates.Then,a weighted spatial pattern(WSP)was developed.After weighting,the neighboring trees were replaced,the replacement ratio was 38.3%,and there was 57.4%of the central tree.Correlation analysis showed that the uniform angle index of the WSP was significantly correlated with the tree size standard deviation under uniformity(r=0.932)and randomness(r=0.711).The DTM method not only considers the spatial distance between trees,but also considers the non-spatial attributes of trees.By changing the spatial topological relation between trees,this method further improves the spatial structure measurement of forest.

Density-dependent shock Hugoniot of polycrystalline diamond at pressures relevant to ICF

In inertial confinement fusion(ICF),polycrystalline diamond-referred to as high density carbon(HDC)-has become a promising ablator candidate.However,with smaller grain size and lower initial density,the equation of state(EOS)for HDC can deviate from that for single-crystal diamond,which could be a concern for ICF designs,but current experimental EOS studies for HDC are far from sufficient to clarify how initial density affects target compressibility.Presented here are measurements of the Hugoniot for HDC with an initial density of 3.23 g/cm^(3) at pressures of 17–26 Mbar.Combined with experimental data reported for nanocrystalline diamond(NCD),a stiffer compressibility of NCD due to lower initial density is confirmed.Two porous models are used for comparison and seem to offer better agreement compared with SESAME databases.Also,the effect of temperature on the Gruneisen parameter,which is usually neglected,might need to be considered for NCD under these conditions.The present data offer important support for EOS studies relevant to ICF and constrain the construction of wide-range EOS.

Analysis of the Influence Factors of Grain Supply-Demand Gap in China

Based on the analysis of the grain supply and demand gap’s current situation in China, this paper establishes an indicator system for the influence factors of grain supply and demand gap. Then this paper calculates the correlation degree between the main grain varieties’ supply and demand gap and its influence factors. The results show that sown area and unit yield have the greatest impact on wheat supply and demand gap;per capita disposable income and unit yield have the greatest impact on corn supply and demand gap;per capita disposable income and agricultural mechanization level have the greatest impact on the supply and demand gap of soybean and rice. From the analysis results, we can obtain the difference between the factors affecting the grain supply and demand gap, and provide a certain theoretical basis and new ideas for the balance of grain supply and demand in China.

Analysis and Forecast of China’s Grain Supply and Demand Quality Grade Structural Balance

Based on the analysis of China’s grain production and demand quality grade, this paper uses the non-equidistance GM (1,1) model and the inference algorithm to predict the structural balance of the supply and demand grades of China’s four major grain crops. The results show that the supply and demand for wheat, corn and rice can maintain a quantitative balance. While, it’s difficult to achieve a quality grade balance in wheat and rice and keep a supply and demand balance in terms of quantity and quality of soybean. Simultaneously, the supply of premium grade corn is greater than the demand. The analysis and prediction results can reflect the existing structural balance matter of grain supply and demand at different quality grades in China, and provide theoretical basis for governments to formulate relevant policies.

Multilevel Correlation Analysis of Influencing Factors on Grain Total Factor Productivity in Main Grain Producing Provinces of China

In order to analyze the influencing factors of TFP (the abbreviation of Total Factor Productivity) deeply, this paper calculates and decomposes the TFP of the main grain producing provinces in China from 2006 to 2015 by the DEA-Malmquist index model. On the basis of this, the grey correlation analysis model based on super-efficiency DEA is used to quantitatively analyze the influencing factors of total factor productivity, technological progress and technical efficiency. The results show that the proportion of grain sowing, the level of food economic development, the level of grain mechanization, the average scale of operations and the level of fertilizer using have the most influence on grain total factor productivity. Finally, according to the results of the analysis, some suggestions are put forward to improve the TFP of different provinces in the main grain producing areas.

Research Progress on the Application of Icariin in Osteoarthritis Treatment

Osteoarthritis(OA)is a multifaceted bone and joint disease with degenerative changes of articular cartilage.Therefore,the current research on the etiology of OA mainly focuses on the etiology of articular cartilage degeneration.Clarifying the pathogenesis of OA from the molecular level has become an important research topic in the field of orthopedics.Its main pathological features are the decrease of chondrocyte metabolic activity,cartilage matrix degradation,and osteophyte formation.Icariin(ICA)is the main active monomer of epimedium,a traditional Chinese medicine,and the pharmacological research has revealed favorable effects of ICA on the bone system.ICA can promote the proliferation of chondrocytes and inhibit the apoptosis of chondrocytes,alleviate the degradation rate of cartilage matrix,and effectively protect articular cartilage.This review also expounds the mechanism of promoting cartilage repair.

Energy Absorption by 3D-Printed Mesh Structures with a Negative Poisson’s Ratio

A negative Poisson's ratio(NPR)structure represents optimal impact-resistance with applications in various fields,including the crash box in vehicles,which absorbs impact kinetic energy.The crash box is designed to deform in response to impact,increasing local structural density,which enhances impact resistance performance.Current studies have only focused on the NPR effect in the plane dimension at low-speed loads.Few studies have considered high-speed impact loads on three-dimensional NPR structures.We have developed two types of AlSi10Mg alloy energy-absorbing structures with NPR using three-dimensional printing technology,and have compared our systems with a conventional hexagonal mesh structure.Sample testing involved split-Hopkinson pressure bar measurements,which showed good agreement with dynamic numerical simulations.When subjected to an impact load,the NPR structure exhibited better impact resistance and energy absorption compared with the positive Poisson's ratio structure.The proposed dual-layer hexagonal structure ensures an NPR effect while exhibiting higher strength and improved stability relative to the conventional concave hexagon structure.

Additive manufacturing of metallic glasses and high-entropy alloys:Significance,unsettled issues,and future directions

As two kinds of well-known prominent high-performance alloys,metallic glasses(MGs)and high-entropy alloys(HEAs)have attracted increasing attention.Most of them contain multiple alloying components,demonstrate intriguing microstructures,and exhibit excellent properties;however,their unique performances are closely dependent on the fabrication process,although they are limited due to the need for rapid solidification during fabrication.On the other hand,additive manufacturing(AM)can be used to fabricate complex parts via rapid solidification,thus saving materials.These advantages provide AM with a great possibility to produce MG and HEA materials with tunable microstructures therefore properties,and corresponding parts with complex geometries,large dimensions,and more functions.This paper provides a comprehensive and systematic overview of the manufacturing and properties of MGs and HEAs using AM techniques.The correlation between MGs and HEAs with conventional manufacturing meth-ods and the difficulties encountered are retrospectively discussed.Afterward,this review specifically focuses on the recent research advances in MGs and HEAs fabricated using AM technologies.Then,various properties of the AM-fabricated MGs and HEAs are discussed.Finally,the remaining issues and potential solutions,challenges,and future directions on the AM of MGs and HEAs are also presented.

A“T.E.S.T.”hydrogel bioadhesive assisted by corneal cross-linking for in situ sutureless corneal repair

Corneal transplantation is an effective clinical treatment for corneal diseases,which,however,is limited by donor corneas.It is of great clinical value to develop bioadhesive corneal patches with functions of“Transparency”and“Epithelium&Stroma generation”,as well as“Suturelessness”and“Toughness”.To simultaneously meet the“T.E.S.T.”requirements,a light-curable hydrogel is designed based on methacryloylated gelatin(GelMA),Pluronic F127 diacrylate(F127DA)&Aldehyded Pluronic F127(AF127)co-assembled bi-functional micelles and collagen type I(COL I),combined with clinically applied corneal cross-linking(CXL)technology for repairing damaged cornea.The patch formed after 5 min of ultraviolet irradiation possesses transparent,highly tough,and strongly bio-adhesive performance.Multiple cross-linking makes the patch withstand deformation near 600%and exhibit a burst pressure larger than 400 mmHg,significantly higher than normal intraocular pressure(10-21 mmHg).Besides,the slower degradation than GelMA-F127DA&AF127 hydrogel without COL I makes hydrogel patch stable on stromal beds in vivo,supporting the regrowth of corneal epithelium and stroma.The hydrogel patch can replace deep corneal stromal defects and well bio-integrate into the corneal tissue in rabbit models within 4 weeks,showing great potential in surgeries for keratoconus and other corneal diseases by combining with CXL.

Design of FeSiBPCu soft magnetic alloys with good amorphous forming ability and ultra-wide crystallization window

The Fe_(81.3)Si_(4)B_(13–x)PxCu_(1.7) soft magnetic alloys with high Cu and proper P elements addition were synthesized with the aim of ensuring the amorphous forming ability(AFA)while expanding the crystallization window(CW).It is found that the atomic ratio of P/Cu of∼3 is advantageous for AFA whereas a small amount of P addition promotes the precipitation ofα-Fe grains and excessive P addition induces surface crystallization behavior of the present alloys.High Cu concentration can expand the annealing temperature(Ta)window whereas proper P addition effectively expands the annealing time(ta)window.The Fe_(81.3)Si_(4)B_(13-x)PxCu_(1.7) soft magnetic alloy was successfully synthesized with a large Ta window of up to 130°C and ta window of 90 min,which is a breakthrough for nanocrystalline alloys with high saturation magnetization.Microstructure analysis reveals that the ultra-wide CW is related to the unique nucleation mechanism,that is,theα-Fe grains are precipitated attaching to the Cu or CuP clusters and enveloping the Cu clusters,resulting in the high number density ofα-Fe nanocrystals.The ultra-wide CW promises the potential material in flexibly choosing the annealing process according to the performance.

Impact of ablation ratio on 5-year postoperative posterior corneal stability after refractive surgery:SMILE and FS-LASIK

Background:To investigate the impact of the ablation ratio on 5-year postoperative posterior corneal stability in myopic eyes after small incision lenticule extraction(SMILE)and femtosecond laser-assisted in situ keratomileusis(FS-LASIK)surgery.Methods:A prospective,nonrandomized,cohort study:80 eyes of 43 patients underwent SMILE surgery and 63 eyes of 32 patients underwent FS-LASIK surgery at the EYE&ENT Hospital,Fudan University.Ablation ratio Was defined as lenticule thickness(SMILE cases)or ablation depth(FS-LASIK cases)divided by central corneal thickness(CCT).Posterior corneal elevation changes were recorded as posterior central elevation(PCE),posterior corneal surface at thinnest point(PTE)and posterior corneal mean elevation(PME).Patients were followed up at 6-month and 5-year intervals to investigate the impact of the ablation ratio on posterior corneal elevation after SMILE and FS-LASIK surgery.Results:PCE dropped at the 6-month follow-up for both SMILE(decreased by-1.11±2.93μm,P<0.05)and FSLASIK groups(decreased by-0.46±3.72μm,P<0.05).PTE also dropped in SMILE(reduced by-2.04±3.02μm,P<0.05)and FS-LASIK group(reduced by-1.28±4.21μm,P<0.05)at the 6-month follow-up.Stable PCE(elevation change:SMILE-0.28±4.03μm;FS-LASIK 0.79±4.13μm,P>0.05)and PTE(elevation change:SMILE-0.08±4.28μm;FS-LASIK 1.42±3.85μm,P>0.05)for both groups were recorded at the 5-year follow-up compared to the 6-month visit.Ablation ratio was strongly correlated with 5-year postoperative PCE(β=2.68±1.05,P<0.01)and PTE(β=2.35±1.17,P<0.05).Cut-off value raised for 5-year postoperative PCE and PTE was 27.3%and 27.1%,respectively.Conclusions:Ablation ratio was strongly correlated with postoperative posterior corneal elevation in a 5-year follow-up in both SMILE and FS-LASIK groups.PCE and PTE underwent slight backward displacement 6 months postoperatively and remain stable at the 5-year follow-up.Threshold of the ablation ratio for resisting forward displacement of posterior corneal surface Was 27.3%and 27.1%for SMILE and FS-LASIK groups,respectively.

Investigation Into the Electromagnetic Impulses From Long- Pulse Laser Illuminating Solid Targets Inside a Laser Facility

Emission of the electromagnetic pulses （EMP） due to laser-target interaction in laser facility had been evaluated using a cone antenna in this work. The microwave in frequencies ranging from several hundreds of MHz to 2 GHz was recorded when long-pulse lasers with several thousands of joules illuminated the solid targets, meanwhile the voltage signals from 1V to 4V were captured as functions of laser energy and backlight laser, where the corresponding electric field strengths were obtained by simulating the cone antenna in combination with conducting a mathematical process （Tiknohov Regularization with L curve）. All the typical coupled voltage oscillations displayed multiple peaks and had duration of up to 80ns before decaying into noise and mechanisms of the EMP generation was schematically interpreted in basis of the practical measuring environments. The resultant data were expected to offer basic know-how to achieve inertial confinement fusion.

Impact of ablation ratio on 5-year postoperative posterior corneal stability after refractive surgery:SMILE and FS-LASIK

Background:To investigate the impact of the ablation ratio on 5-year postoperative posterior corneal stability in myopic eyes after small incision lenticule extraction(SMILE)and femtosecond laser-assisted in situ keratomileusis(FS-LASIK)surgery.Methods:A prospective,nonrandomized,cohort study:80 eyes of 43 patients underwent SMILE surgery and 63 eyes of 32 patients underwent FS-LASIK surgery at the EYE&ENT Hospital,Fudan University.Ablation ratio was defined as lenticule thickness(SMILE cases)or ablation depth(FS-LASIK cases)divided by central corneal thickness(CCT).Posterior corneal elevation changes were recorded as posterior central elevation(PCE),posterior corneal surface at thinnest point(PTE)and posterior corneal mean elevation(PME).Patients were followed up at 6-month and 5-year interval to investigate the impact of the ablation ratio on posterior corneal elevation after SMILE and FSLASIK surgery.Results:PCE dropped at the 6-month follow-up for both SMILE(decreased by−1.11±2.93μm,P<0.05)and FSLASIK groups(decreased by−0.46±3.72μm,P<0.05).PTE also dropped in SMILE(reduced by−2.04±3.02μm,P<0.05)and FS-LASIK group(reduced by−1.28±4.21μm,P<0.05)at the 6-month follow-up.Stable PCE(elevation change:SMILE−0.28±4.03μm;FS-LASIK 0.79±4.13μm,P>0.05)and PTE(elevation change:SMILE−0.08±4.28μm;FS-LASIK 1.42±3.85μm,P>0.05)for both groups were recorded at the 5-year follow-up compared to the 6-month visit.Ablation ratio was strongly correlated with 5-year postoperative PCE(β=2.68±1.05,P<0.01)and PTE(β=2.35±1.17,P<0.05).Cut-off value for 5-year postoperative raised PCE and PTE was 27.3 and 27.1%,respectively.Conclusions:Ablation ratio was strongly correlated with postoperative posterior corneal elevation in a 5-year follow-up in both SMILE and FS-LASIK groups.PCE and PTE underwent slight backward displacement 6-month postoperatively and remain stable at the 5-year follow-up.Threshold of the ablation ratio for resisting forward displacement of posterior corneal surface was 27.3 and 27.1%for SMILE and FS-LASIK groups,respectively.

Microstructure and soft-magnetic properties of FeCoPCCu nanocrystalline alloys

Fe(83.2-x)CoxP(10)C6Cu(0.8)(x=0,4,6,8 and 10)alloys with a high amorphous-forming ability and good softmagnetic properties were successfully synthesized.Saturation magnetic flux density(Bs)is effectively enhanced from 1.53 T to 1.61 T for as-quenched alloy by minor Co addition,which is consistent well with the result of the linear relationship between average magnetic moment and magnetic valence.For Cocontained alloys,the value of corecivity(Hc)is mainly determined by magneto-crystalline anisotropy,while effective permeability(μe)is dominated by grain size and average saturation polarization.After proper heat treatment,the Fe(79.2)Co4P(10)C6Cu(0.8)nanocrystalline alloy exhibited excellent soft-magnetic properties including a high Bsof 1.8 T,a low Hcof 6.6 A/m and a highμeof 15,510,which is closely related to the high volume fraction of α-(Fe,Co)grains and refined uniform nanocrystalline microstructure.

Structural homology of the strength for metallic glasses

The structure-property relationship,one of the central themes in materials science,is far from being well understood for metallic glasses(MGs)due to the great complexity of their amorphous structures.Based on the analysis of published experimental data for 165 MGs from more than 15 different alloy systems,the present study reveals a universal dependence of mechanical properties(Young’s moduli,shear moduli and yield strength)on simple structural parameters(the inter-atomic distance and/or valence electron density)originating from the interatomic potential and Fermi sphere-Brillouin zone interaction.This work establishes a structure-property relationship for metallic glasses and provides insights into the fundamentals of the mechanical properties of disordered systems.

Numerical simulation of oxide nanoparticle growth characteristics under the gas detonation chemical reaction by space-time conservation element-solution element method

Under harsh conditions （such as high temperature, high pressure, and millisecond lifetime chemical reaction）, a long-standing challenge remains to accurately predict the growth characteristics of nanosize spherical particles and to determine the rapid chemical reaction flow field characteristics, The growth characteristics of similar spherical oxide nanoparticles are further studied by successfully introducing the space-time conservation element-solution element （CE/SE） algorithm with the monodisperse Kruis model. This approach overcomes the nanosize particle rapid growth limit set and successfully captures the characteristics of the rapid gaseous chemical reaction process. The results show that this approach quantitatively captures the characteristics of the rapid chemical reaction, nanosize particle growth and size distribution. To reveal the growth mechanism for numerous types of oxide nanoparticles, it is very important to choose a rational numerical method and particle physics model.

Inheritance factor on the physical properties in metallic glasses

Material genetic engineering can significantly accelerate the development of new materials.As an important topic in material science and condensed matter physics,the development of metallic glasses(MGs)with specific properties has largely been the result of trial and error since their discovery in 1960.Yet,property design based on the physical parameters of constituent elements of MGs remains a huge challenge owing to the lack of an understanding of the property inheritance from constitute elements to the resultant alloys.In this work,we report the inherent relationships of the yield strengthσ_(y),Young’s modulus E,and shear Modulus G with the valence electron density.More importantly,we reveal that the electronic density of states(EDOSs)at the Fermi surface(E_(F))is an inheritance factor for the physical properties of MGs.The physical properties of MGs are inherited from the specific element with the largest coefficient of electronic specific heat(γ_(i)),which dominates the value of the EDOS at E_(F).This work not only contributes to the understanding of property inheritances but also guides the design of novel MGs with specific properties based on material genetic engineering.