Multiple Solutions for a Class of Singular Boundary Value Problems of Hadamard Fractional Differential Systems with p-Laplacian Operator

This paper discusses the existence and multiplicity of positive solutions for a class of singular boundary value problems of Hadamard fractional differential systems involving the p-Laplacian operator. First, for the sake of overcoming the singularity, sequences of approximate solutions to the boundary value problem are obtained by applying the fixed point index theory on the cone. Next, it is demonstrated that these sequences of approximate solutions are uniformly bounded and equicontinuous. The main results are then established through the Ascoli-Arzelà theorem. Ultimately, an instance is worked out to test and verify the validity of the main results.

超深井自动控制压井室内物理模拟试验及结果分析

现有超深井溢流压井技术依靠手动控制节流管汇,响应速度慢,井筒压力波动大,容易引发二次溢流、漏失等复杂情况,而自动控制压井技术可实现钻井时溢流压井作业稳定控制。为此,设计了比例–积分–微分(PID)与位移双层协同反馈的自动控制方法,开发了超深井自动控制压井系统,建立了自动控制压井物理模拟试验装置,开展了恒定目标压力、连续变化目标压力、压力突变干扰等条件下的自动控制压井试验。试验结果表明,自动控制压井系统能够在30 s左右完成节流阀开度的调节,节流压力波动范围小于0.02 MPa,与手动控制压井相比,自动控制压井系统具有良好的稳定性、准确性、反应速度和抗干扰能力。研究结果为超深井复杂地层安全压井提供了理论依据。

大健康背景下基于OBE理念的“功能食品学”专业课程教学改革与实践

在大健康背景下,基于OBE(outcome-based education)教育理念,紧密结合课程育人目标,坚持以学生为中心,从课程教学目标确定、教学内容体系重构、在线课程建设、多元化教学模式探索与实践、课程考核评价方式优化、第二课堂历练等方面开展“功能食品学”课程教学改革与实践,旨在增强学生对功能食品开发与研制基础理论和关键技术的理解与掌握,为进一步实现科学认知保健食品、明白理性放心消费、有效助推全民健康,以及为培养符合功能食品行业需求的高素质应用型人才奠定基础,也为新工科建设背景下高等院校专业课程的教学研究与改革提供有益参考。

秀丽隐杆线虫在食品营养功能评价中的研究进展

秀丽隐杆线虫作为一种理想的模式生物,已被越来越多地应用于食品营养功能的评价。与细胞、小鼠等其他模型比较,线虫具有体积小、寿命短、与人类基因同源性高、研究结果易于观察且能够在实验室大批量培养等优点。文章综述了秀丽隐杆线虫在抗肥胖、抗氧化、抗衰老的食品营养功能评价中的研究方法、潜在机理及研究进展,并展望了秀丽隐杆线虫在食品抗肥胖、抗氧化、抗衰老中的研究前景。

食用菌不同部位风味物质差异及其对食品风味影响研究进展

食用菌风味独特,不同部位香气物质存在差异,滋味物质也大有不同。基于食用菌不同部位风味物质研究现状,选取香菇(Lentinus edodes)、松茸(Tricholoma matsutake)、猴头菇(Hericium erinaceus)、牛肝菌(Boletus)、真姬菇(Hypsizygus marmoreus)和大球盖菇(Stropharia rugosoannulata)6种营养、经济价值较高的食用菌,综述其风味物质种类和不同部位风味物质差异,以及添加食用菌对食品风味的影响,旨在为食用菌的风味研究、产品开发和副产品高值化利用提供有益参考。

脑小血管病诊断和鉴别诊断的最新进展

脑小血管病(CSVD)是一种对我国人民健康产生严重影响的常见疾病。该疾病进展隐匿,可能被患者和临床医师忽视。近些年,对于CSVD的危险因素、发病机制、临床表现以及评价体系的研究取得一些进展。2013年,国际血管改变神经影像标准(STRIVE)协作组对CSVD的定义与描述进行了规范性的梳理。2021年,本团队发布了《中国脑小血管病诊治专家共识2021》,整合了最新的国内外研究成果。在2023年,国际STRIVE协作组进一步更新了CSVD领域的研究进展。在临床表现上,CSVD与神经退行性病变相似,特异性不够显著。尽管遗传检测和脑组织活检对于确诊有一定帮助,但由于技术和经费限制,这些方法在临床中并不常用。目前,神经影像学技术是主要用于检测CSVD引发的脑组织病变并作出诊断的手段。本文将集中讨论用于CSVD诊断的影像学标志,并深入探讨CSVD的影像鉴别诊断。

基于流式细胞仪的激光器驱动系统研究与设计

为获得适用于流式细胞仪的功率稳定、波长稳定、低噪声的激光光源,设计了一款恒功率控制的半导体激光器驱动系统。系统采用多量子阱激光二极管,以STM32为主控核心,以MAX8521芯片为温度控制核心,采用双闭环功率控制,实现对激光器输出光功率的高精度低噪声控制。实验结果表明,该系统的温度波动在±0.016℃范围内,温度控制不稳定度为±0.055%,输出光功率长期不稳定度为±0.078%,光噪声率为0.109%,输出光波长稳定在637~638 nm,仪器分辨率的全峰宽变异系数均小于等于1.70%,优于YY/T0588-2017流式细胞仪行业标准的要求。所设计的半导体激光器驱动系统温控精度高、输出长期稳定、光噪声小、成本低,能够有效满足流式细胞仪检测的需求。

海洋一号卫星观测任务规划算法设计及系统应用

针对海洋一号卫星观测任务规划需求,提出并实现了基于遗传策略的任务规划框架,解决了卫星实际使用中成像任务受卫星其他业务影响的多类型约束成像规划问题。基于海洋一号卫星实际规划业务要求,对任务规划约束和优化目标建立数学模型,提出了由预处理、窗口约束处理和组合约束处理与优化组成的三阶段规划框架。设计了多约束任务规划优化目标函数,并利用交叉、变异和种群选择等遗传机制对优化问题进行了求解。基于海洋一号卫星实际观测需求数据,对提出的算法进行了有效性和性能验证,结果表明本算法能够给出满足多类型约束的观测规划方案,并在观测时间、观测覆盖率等方面较其他策略有显著提升。研究结果表明通过优化目标函数的设计遗传算法能够实现复杂约束条件的成像规划求解,算法框架可为与海洋卫星具有相似业务特点的对地观测规划系统设计提供借鉴。

Sorl1 knockout inhibits expression of brain-derived neurotrophic factor:involvement in the development of late-onset Alzheimer's disease

Sortilin-related receptor 1(SORL1)is a critical gene associated with late-onset Alzheimer’s disease.SORL1 contributes to the development and progression of this neurodegenerative condition by affecting the transport and metabolism of intracellularβ-amyloid precursor protein.To better understand the underlying mechanisms of SORL1 in the pathogenesis of late-onset Alzheimer s disease,in this study,we established a mouse model of SorI1 gene knockout using cluste red regularly inters paced short palindro mic repeats-associated protein 9 technology.We found that Sorl1-knocko ut mice displayed deficits in learning and memory.Furthermore,the expression of brain-derived neurotrophic factor was significantly downregulated in the hippocampus and co rtex,and amyloidβ-protein deposits were observed in the brains of 5orl1-knockout mice.In vitro,hippocampal neuronal cell synapses from homozygous Sorl1-knockout mice were impaired.The expression of synaptic proteins,including Drebrin and NR2B,was significantly reduced,and also their colocalization.Additionally,by knocking out the Sorl1 gene in N2a cells,we found that expression of the N-methyl-D-aspartate receptor,NR2B,and cyclic adenosine monophosphate-response element binding protein was also inhibited.These findings suggest that SORL1 participates in the pathogenesis of late-onset Alzheimer s disease by regulating the N-methyl-D-aspartate receptor NR2B/cyclic adenosine monophosphate-response element binding protein signaling axis.

基于类别感知与重加权的多源域自适应算法

多源域自适应是迁移学习中的一个重要分支,类别偏移是多源域自适应领域的热点难题之一,其本质是源域和目标域类别分布不匹配的问题。针对此问题,提出了一种基于类别感知与重加权的多源域自适应算法,该算法通过类别感知策略增强相似类别间的正向迁移;同时,引入重加权矩匹配策略,减少不同层面的分布差异;此外,利用伪标签构建自适应权重,有效降低类别偏移的影响。在Digits-five和Office-Caltech10两个数据集上的任务分类准确率分别达到了94.11%和97.18%,实验结果表明,所提算法相比于当前典型的多源域自适应算法在类别偏移场景下的准确性方面有显著提升。

深基坑工程不同施工阶段对其围护结构及临近在役铁路路基稳定性影响分析

为研究基坑工程不同施工阶段对基坑围护结构及临近在役铁路稳定性的影响,针对盐城市铁路综合客运枢纽能源中心深基坑工程,首先分析不同施工阶段对基坑围护结构变形量的影响;然后基于临近铁路路基沉降变形监测数据,分析各施工阶段对铁路路基稳定性的影响。研究结果表明:土方开挖过程中基坑圈梁水平和竖向位移、支撑轴力、格构柱竖向位移均呈逐步增大的变化规律,支撑施工及底板浇筑过程中基坑各结构的位移量及支撑轴力逐步减小;随着施工进程的不断推进,铁路路基的竖向位移逐渐增大,直至拆撑结束后逐渐趋于稳定。最后通过收集若干基坑开挖对临近铁路路基影响的工程实例,发现铁路路基最大沉降值S_(max)与mH_(e)/L_(t)(m为基坑靠近路堤一侧的宽度、L_(t)为基坑坑壁至路基坡脚线的水平净距、H_(e)为基坑开挖深度)存在良好的对数关系。

Hyphae-mediated bioassembly of carbon fibers derivatives for advanced battery energy storage

Ingenious design and fabrication of advanced carbon-based sulfur cathodes are extremely important to the development of high-energy lithium-sulfur batteries,which hold promise as the next-generation power source.Herein,for the first time,we report a novel versatile hyphae-mediated biological assembly technology to achieve scale production of hyphae carbon fibers(HCFs)derivatives,in which different components including carbon,metal compounds,and semiconductors can be homogeneously assembled with HCFs to form composite networks.The mechanism of biological adsorption assembly is also proposed.As a representative,reduced graphene oxides(rGOs)decorated with hollow carbon spheres(HCSs)successfully co-assemble with HCFs to form HCSs@rGOs/HCFs hosts for sulfur cathodes.In this unique architecture,not only large accommodation space for sulfur but also restrained volume expansion and fast charge transport paths are realized.Meanwhile,multiscale physical barriers plus chemisorption sites are simultaneously established to anchor soluble lithium polysulfides.Accordingly,the designed HCSs@rGOs/HCFs-S cathodes deliver a high capacity(1189 mA h g^(-1)at 0.1 C)and good high-rate capability(686 mA h g^(-1)at 5 C).Our work provides a new approach for the preparation of high-performance carbon-based electrodes for energy storage devices.

Aboveground carbon sequestration of Cunninghamia lanceolata forests:Magnitude and drivers

Understanding the spatial variation,temporal changes,and their underlying driving forces of carbon sequestration in various forests is of great importance for understanding the carbon cycle and carbon management options.How carbon density and sequestration in various Cunninghamia lanceolata forests,extensively cultivated for timber production in subtropical China,vary with biodiversity,forest structure,environment,and cultural factors remain poorly explored,presenting a critical knowledge gap for realizing carbon sequestration supply potential through management.Based on a large-scale database of 449 permanent forest inventory plots,we quantified the spatial-temporal heterogeneity of aboveground carbon densities and carbon accumulation rates in Cunninghamia lanceolate forests in Hunan Province,China,and attributed the contributions of stand structure,environmental,and management factors to the heterogeneity using quantile age-sequence analysis,partial least squares path modeling(PLS-PM),and hot-spot analysis.The results showed lower values of carbon density and sequestration on average,in comparison with other forests in the same climate zone(i.e.,subtropics),with pronounced spatial and temporal variability.Specifically,quantile regression analysis using carbon accumulation rates along an age sequence showed large differences in carbon sequestration rates among underperformed and outperformed forests(0.50 and 1.80 Mg·ha^(-1)·yr^(-1)).PLS-PM demonstrated that maximum DBH and stand density were the main crucial drivers of aboveground carbon density from young to mature forests.Furthermore,species diversity and geotopographic factors were the significant factors causing the large discrepancy in aboveground carbon density change between low-and high-carbon-bearing forests.Hotspot analysis revealed the importance of culture attributes in shaping the geospatial patterns of carbon sequestration.Our work highlighted that retaining largesized DBH trees and increasing shade-tolerant tree species were important to enhance carbon sequestration in C.lanceolate forests.

梯度纳米纤维膜在纯生啤酒中的除菌过滤研究

针对目前商业化纯生啤酒用除菌滤膜存在孔径分布宽、抗污性差、膜孔易堵塞、可重复使用性差等问题,利用熔融挤出相分离法制备了不同直径大小的乙烯-乙烯醇共聚物(EVOH),通过将粗、细纳米纤维在上、下层的先后排列构筑了一种梯度结构纳米纤维膜。通过对梯度纳米纤维膜过滤性能、抗污性及可重复使用性等进行研究,发现梯度纳米纤维膜对10 g/L的酵母浸膏发酵液重复过滤后,稳定后的通量为22660 L m^(-2)h^(-1),远高于Pall®商业膜(4840 L m^(-2)h^(-1))。经高温蒸汽灭菌处理后的梯度纳米纤维膜的稳定通量为6600 L m^(-2)h^(-1),而商业膜仅为1760 L m^(-2)h^(-1),表现出优异的耐高温水蒸气性能。此外,污染后的梯度纳米纤维膜经80℃水清洗后的通量恢复率可达43%,而商业膜的通量恢复率仅为32%,表明梯度纳米纤维膜显示了优异的可重复使用性。为纯生啤酒用除菌滤膜的国产化替代提供了一种新的途径。

Analysis of Bright Source Hardness Ratios in the 4 yr Insight-HXMT Galactic Plane Scanning Survey Catalog

We conduct a statistical analysis of the hardness ratio(HR)for bright sources in the 4 yr Galactic Plane Scanning Survey catalog of Insight-HXMT.Depending on the stable(variable)flux F_(s)(F_(v))or spectrum S_(s)(S_(v))of each source,the bright sources are classified into three groups:F_(v)&S_(v),F_(v)&S_(s),and F_(s)&_(s).Our study of the HR characteristics in different types of sources reveals that accretion-powered neutron star(NS)low-mass X-ray binaries(LMXBs)exhibit softer energy spectra than NS high-mass X-ray binaries(HMXBs),but harder energy spectra than black hole binaries in most cases.This difference is probably due to their different magnetic field strengths.Additionally,Fv&Sv LMXBs tend to be harder than Fv&Ss LMXBs below 7 keV,while the opposite is true for HMXBs.Our results suggest that LMXBs may dominate unclassified sources,and NS binaries are likely to be the primary type of X-ray binaries with ambiguous compact stars.By comparing the HR of transient sources in their outburst and low-flux states,it is found that the averaged HR of four sources in the two states are roughly comparable within uncertainties.We also investigate the spatial properties of the three groups and find that Fv&Sv sources are mainly located in the longitude of-20°<l<9°,Fv&Ss sources cross the Galactic Plane,and Fs&Ss sources are predominantly concentrated in 19°<l<42°.In addition,analyzing the HR spatial distributions shows the absorption of soft X-rays(primarily below 2 keV)in the Galactic Plane.

基于数字孪生的车间生产数据感知方法设计及实现

针对传统车间在进行数字孪生时,对于生产数据的采集存在着目标单一、信息模型灵活性差以及通用性低等问题,提出了一种面向数字孪生的车间生产数据感知方法。首先,通过分析数字孪生车间生产数据采集与应用需求,提出了一种多层次的生产数据采集体系架构;其次,围绕该体系架构的处理层,针对基于OPC统一架构(OPC Unified Architecture,OPC UA)的生产资源数字化表征模型构建关键技术进行了重点阐述;最后,基于车间应用实例,结合关键技术以及体系架构开发了数字孪生系统,验证了该方法的可行性,有效支撑了装配车间数字孪生系统的运行。

基于原型嵌入图网络的小样本图像分类

针对在小样本图像分类中传统骨干卷积网络进行特征提取时会有上下文信息单一和感受野受限以及边特征相似度度量缺乏全局性问题,本文提出了一种基于原型嵌入图网络的小样本图像分类算法。首先,将CBAM产生的权重值与ASPP以不同采样率获取的不同尺度特征进行相乘的特征作为图网络的节点嵌入特征。然后,采用原型网络的方法在度量模块中构建了原型节点,使得成对节点之间的相似性计算转化为单个节点与原型节点相似性的和计算,将得到的相似度作为边特征输入图神经网络。最后,利用双图结构在多个更新代后将标签信息从有标签样本传播到无标签样本。在以ResNet-12为骨干卷积网络的算法分类任务中,本文在mini ImageNet、tiered ImageNet、CUB-200-2011和CIFAR-FS 4个数据集上的5-way 1-shot的任务分类准确率分别达到了71.47%、75.41%、86.21%和79.84%,在以Conv-4作为骨干卷积网络中,本文提出的算法在5-way 1-shot和5-way 5-shot任务中都优于现有的图网络方法。

银杏酸纯化、结构修饰及活性研究进展

银杏酸(ginkgolic acid,GA)是一种酚酸类的小分子有机化合物,是以银杏(Ginkgo biloba L)为主要原料的提取物,主要存在于银杏外种皮中。由于具有明显细胞毒性,因而被规定为制剂的限制性指标成分,但同时也具有极强的研究与应用价值。近些年来,有关于银杏酸的研究报道越来越多,使其已逐渐成为了热点研究之一。现今对近些年银杏酸的纯化以及其衍生物生物活性的相关研究进行综述,并着重介绍了银杏酸其母核结构的几种修饰途径,总结了初步的构效关系,以期为今后银杏酸的科学研究提供参考价值,为今后充分利用我国的银杏资源,为银杏酸的大规模生产提供理论依据。

Backward scattering of laser plasma interactions from hundreds-of-joules broadband laser on thick target

The use of broadband laser technology is a novel approach for inhibiting processes related to laser plasma interactions(LPIs).In this study,several preliminary experiments into broadband-laser-driven LPIs are carried out using a newly established hundreds-of-joules broadband second-harmonic-generation laser facility.Through direct comparison with LPI results for a traditional narrowband laser,the actual LPI-suppression effect of the broadband laser is shown.The broadband laser had a clear suppressive effect on both back-stimulated Raman scattering and back-stimulated Brillouin scattering at laser intensities below 1×10^(15) W cm^(−2).An abnormal hot-electron phenomenon is also investigated,using targets of different thicknesses.

能谱CT在胃肠食管癌诊断中的应用进展

胃肠道食管癌症是全球癌症发病和死亡的主要原因。胃肠道食管癌症的准确诊断对患者精准治疗、延长生命周期至关重要。能谱CT较常规CT提高了病变的检出率,术前能定量检测和描绘病灶及其周围组织内病变,对病灶进行良恶性定性诊断、术前精确分期、组织学分化程度判定具有一定价值,利于临床治疗策略的选择和改善患者预后,提高生存率。本文对能谱CT在诊断胃肠道食管癌症中的研究作一综述。