Helicobacter pylori isolates from ethnic minority patients in Guangxi:Resistance rates,mechanisms,and genotype

AIM: To investigate the rate of Helicobacter pylori (H. pylori) resistance to clarithromycin among ethnic minority patients in Guangxi, explore the underlying mechanisms, and analyze factors influencing genotype distribution of H. pylori isolates.

The Supply-Demand Analysis and Mechanism Innovation of Chinese Rural Public Goods

The connotation of rural public goods is expounded.The rural public goods refer to the products and labors that satisfy the production and living of rural residents,economic growth and social progress.The rural public goods is characterized by non-excludability,non-competitiveness and indispensability of other general public goods.The supply situation of Chinese government to rural public goods is analyzed,as well as the demand situation of rural public goods,which includes farmers' demand on training,the assistance demand of rural weak groups,farmers' demand on comfortable living conditions and farmers' demand on "soft" public goods.The paths for innovating the supply mechanism of rural public goods are put forward,which cover perfecting the decision mechanism of public goods supply;scientifically distributing the supply responsibility of rural public goods;facilitating the reform of each supporting equipment and exploring the multiple capital collecting channels of rural public goods.

APPLICATION OF THE PROBABILISTIC FRACTURE MECHANICS METHOD OF PREDICTING THE FATIGUE LIFE OF TUBULAR JOINTS

In this paper .fatigue strength of T-type tubularjoints subjected to in-planebending or out-of-plane bending load is investigated By, considering material constantsand initial crack sizes as random variables and applying Monte Carlo simulation method, we have giyen a statistical analvsis on fatigue life. Simultaneously, linearregression analyses of computed resuldts are performed and compared with that of theknown experimental data.

Diffusion Brazing of Mechanically Alloyed Oxide Dispersion Strengthened Materials

The present research exploits diffusion brazing of mechanically alloyed Y 2O_3 dispersion strengthened nick-el-base MA760 and iron-base MA956 alloys using B-and P-containing thin foil and sputter coated interlayers.Microstructures of diffission brazed interface before and after recrystallization annealing were investigated usingoptical metallography, electron microprobe analysis, and transmission electron microscopy. It has been foundthat B and P have a strons influence on the recrystallization behavior of these materials. Too high B or P levelsin the interlayers caused recrystallization of the base alloys during brazing process which was operated at temperatures below normal recrystallization points.

STUDIES ON MECHANIS OF PHOTOSENSITIZED ISOMERIZATION OF NORBORNADIENE DERIVATIVES

Using acridine dyes as sensitizers,the photoisomerization of three norbornadiene derivatives was investigated.The valence isomerization of nor- bornadiene derivatives(Ⅰ_a,Ⅰ_b,Ⅰ_c)gave their corresponding isomers of quadri- cyclane(Ⅱ_a,Ⅱ_b,Ⅱ_c)operating with relatively high efficiency in an electron transfer mode.Their quantum yields of isomerization were determined and the reaction mechanism was discussed.

Thermal and Mechanical Properties of Isotactic Polypropylene/TiO_2 Particulate Composites

Particulate composites based on isotactic polypropylene(iPP) and titanium dioxide(TiO 2) have been prepared and their morphology and thermal behavior investigated by scanning electron microscopy(SEM), differential scanning calorimetry(DSC) and thermogravimetric analysis(TGA). Tensile tests were performed to assess the influence of TiO 2 on the mechanical properties of the iPP.

融合注意力机制卷积神经网络的扬声器异常声分类

针对扬声器异常声非线性、非平稳且易受外部噪声干扰,以及因特征冗余而导致扬声器异常声识别率偏低的问题,提出一种基于变分模态分解(variational mode decomposition, VMD)和一维卷积循环注意力网络(1DCNN-BiLSTM-Attention)相结合的扬声器异常声分类方法。首先,采集不同类型异常声信号,采用VMD对异常声信号进行分解并提取扬声器异常声特征,构建标签化的初始数据;其次,将特征数据输入至1DCNN-BiLSTM网络中进行初始化特征提取,利用注意力机制自适应优化网络对异常声特征的学习权重,提升网络对特征鉴别能力,并优化Dropout抑制网络在训练过程中存在的过拟合问题,构成1DCNN-BiLSTM-Attention分类网络;最后,将所提方法应用于扬声器异常声分类中。实验结果表明:该方法可以有效提取到扬声器异常声中的关键特征,平均分类准确率为99.17%,与VGG16、RF和DCNN相比,其准确率分别提高了13.14%、0.56%,12.34%。

汽车后大灯镜壳大型薄壁精密注塑模设计

根据汽车后大灯镜壳的结构特点,设计了一副大型薄壁精密注塑模具。模具采用定模成型内表面、动模成型外表面及动模侧向抽芯机构,有效地解决了成型塑件脱模困难问题;模具采用三级定位机构,显著提高了模具刚度和寿命;模具采用随形水路温度控制系统,成型周期降低了10%,成型塑件最大变形量下降了20%,成型塑件的尺寸精度达到了设计要求的MT3;模具采用推杆先复位机构,有效地消除了滑块和推杆汽相撞的风险,保证了侧向抽芯机构安全可靠。模具投产后运行平稳,成型塑件尺寸稳定。

High-Level Security Dimension Evaluation of Blockchain BaaS System and Key Technology

In recent years,blockchain technology integration and application has gradually become an important driving force for new technological innovation and industrial transformation.While blockchain technology and applications are developing rapidly,the emerging security risks and obstacles have gradually become prominent.Attackers can still find security issues in blockchain systems and conduct attacks,causing increasing losses from network attacks every year.In response to the current demand for blockchain application security detection and assessment in all industries,and the insufficient coverage of existing detection technologies such as smart contract detectiontechnology,this paper proposes a blockchain core technology security assessment system model,and studies the relevant detection and assessment key technologies and systems.A security assessment scheme based on a smart contract and consensus mechanism detection scheme is designed.And the underlying blockchain architecture supports the traceability of detection results using super blockchains.Finally,the functionality and performance of the system were tested,and the test results show that the model and solutions proposed in this paper have good feasibility.

结合PBL与竞赛机制的《微机原理与接口技术》创新教学体系

《微机原理与接口技术》是高校理工科专业的必修核心课程,旨在培养学生的实践创新能力,在复合应用型人才培养中发挥非常关键的作用。文章以《微机原理与接口技术》课程为例,探讨PBL教学模式与竞赛机制的结合教学在课程中的具体应用,从而创新课程教学体系,为提升教学质量和效率提供有效保障。

羟基乙叉二膦酸对Fe^(2+)活化O_(2)降解污染物的强化效果及机制

羟基乙叉二膦酸(HEDP)常与Fe^(2+)形成Fe^(2+)-HEDP配合物,本文验证了HEDP存在可以促进Fe^(2+)活化分子氧产生活性自由基(ROS),研究结果显示添加2mmol/L HEDP后,Fe^(2+)/O_(2)体系中苯酚(10mg/L)的降解效果从0.69%提升到69.31%,在此过程中,体系中的HEDP还能够实现部分自降解.电子自旋共振(ESR)和掩蔽实验结果表明体系中主要ROS为HO^(•)和O_(2)^(•–),双电子传递途径(O_(2)→H_(2)O_(2)→HO^(•))是体系中产生HO^(•)的主要方式.在3.0~9.0的pH值范围内,HEDP都能够促进ROS的产生和污染物的降解,常见环境阴离子对体系影响较小.

FeCoNiTi_(x)中熵合金组织性能及其在硬质合金中的应用

FeCoNi中熵合金相比传统合金具有优异的性能,但其室温强度不高,限制了其应用。通过机械合金化和放电等离子烧结工艺制备FeCoNiTi_(x)(x=0,0.25,0.50,0.75,1)中熵合金块体,重点研究了各元素机械合金化顺序以及Ti含量对FeCoNiTi_(x)中熵合金显微组织和性能的影响,并初步探讨了FeCoNiTi_(x)中熵合金作为黏结剂在WC基硬质合金中的应用。结果表明:机械合金化过程中FeCoNi基体相为FCC相,添加Ti元素后形成Laves相和钛氧化物相,因此FeCoNiTi_(x)中熵合金物相由FCC相、Laves相和钛氧化物相组成。随着Ti含量的增加,FeCoNiTi_(x)合金密度、硬度和强度均上升,塑性先增强后减弱。FeCoNiTi_(0.50)中熵合金表现出良好的力学性能,其显微硬度、屈服强度、压缩强度和压缩应变分别为531 HV、1 987.57 GPa、2 114.85 GPa和20.5%。添加少量Ti元素可提升FeCoNi合金的耐腐蚀性。FeCoNiTi_(x)黏结剂在WC基硬质合金中能稳定存在,抑制WC烧结过程中脱碳相的形成。WC-FeCoNiTi_(0.50)硬质合金表现出较好的力学性能,其显微硬度与断裂韧性分别为1 834 HV与15.12 MPa·m^(1/2)。

Effect of Deformation Temperature on Microstructure and Mechanical Properties of AZ31 Mg Alloy Processed by Differential-Speed Rolling

A differential-speed rolling(DSR) was applied to AZ31 magnesium alloy sample at different rolling temperatures of 473,523,573,and 623 K with 1-pass and 2-pass operations.The microstructural evolution and mechanical properties of the deformed samples were investigated.The rolling temperature was found to be an important parameter affecting the microstructural development.After DSR at 473 K,the microstructure was more homogeneous than that obtained after deformation by equal-speed rolling(ESR).The fully recrystallized microstructures were generated after DSR at 573 and 623 K.As to mechanical properties,the yield strength(YS) and ultimate tensile strength(UTS) decreased monotonously with increasing rolling temperature.In contrast,the elongation of the DSR-deformed samples was improved as the rolling temperature increased.The strain hardening exponent(n) calculated by Hollomon equation increased with increasing the rolling temperature,which would explain an increase in the uniform elongation.

CINO双通道结合多头注意力机制藏文情感分类方法

为了解决藏文情感分类任务中现有的模型对文本语义信息理解和深层文本特征提取能力不足的问题,该文使用CINO(Chinese Minority PLM)预训练模型来获取动态词向量,通过TextCNN和BiGRU融合的双通道情感分类模型,分别实现获取文本局部特征和深层全局特征,并引入多头自注意力机制引导模型学习更重要的信息。实验结果表明,该文提出的双通道模型准确率高达92.84%,相较于该文的其他对比模型效果更佳。

岩石-混凝土组合体单轴压缩力学与破坏特征数值模拟研究

目的为研究单轴压缩条件下混凝土组分骨料含量、强度等级、占比和界面倾角对岩石-混凝土组合体力学与破坏特征的影响,方法结合凸多边形随机骨料生成投放程序与RFPA2D分析系统,构建组合体数值模型并进行数值模拟。结果组合体的破坏类型可分为由混凝土组分破坏并延伸至花岗岩组分或两种组分及界面共同破坏引起的“两体Ⅰ型和Ⅱ型破坏”,由混凝土组分单独破坏或混凝土组分和界面共同破坏引起的“单体Ⅰ型和Ⅱ型破坏”。对界面处应力状态进行分析,从理论上解释了沿界面宏观裂纹的形成原因;组合体抗压强度接近混凝土的抗压强度,其值与混凝土组分强度等级正相关而与占比负相关;组合体弹性模量数值模拟结果与理论值吻合较好,且与骨料含量和强度等级正相关,与混凝土组分占比和界面倾角负相关;组合体泊松比与骨料含量和混凝土组分占比负相关,强度等级对其影响较小;组合体抗压强度和泊松比均随界面倾角的增加先减小后增加。结论构建了含骨料岩石-混凝土组合体数值模型,并运用RFPA2D分析系统对4种组合方式组合体进行数值模拟,可通过提高混凝土组分强度、降低混凝土组分占比与材料间的界面倾角提升组合体的力学特性。研究结果可为地下或坝体等工程的稳定性分析提供参考依据。

Formation mechanism of micro emulsion on aluminum and lanthanum extraction in P507-HCl system

P507 solvent extraction is the main method to separate and purify the rare earth products.The emulsification may be caused by the impurities in process of extracting rare earths,and these result in huge economic loss and decrease the quality of rare earth products.In recent researches,the extractant was prone to emulsification,and aluminum content of rare earth products also increased,while aluminum concentration of feed was higher.Pointing to this problem,the structural change of saponification P507 extracting aluminum and lanthanum was investigated by infrared spectroscopy,and the results showed that Al ions exchanged with H of P-O-H to become P-O-Al.Because aluminum held the characteristic of hydrophilic after extracted in the form of hydroxyl polymer ions and this provided conditions for the formation of micro emulsion.The organic phase and aqueous phase were investigated by polarizing microscope after aluminum was extracted.The results showed that the organic phase was clear when the extraction capacity of Al was less than 5 g/L.If the extraction capacity of Al exceeded 5 g/L,it formed W/O of ME(micro emulsion),leading to form emulsion of the organic phase.When Al concentration of feed was less than 1 g/L,the aqueous phase would form O/W of ME.If aluminum was extracted by saponification P507 firstly,then the the organic phase loading aluminum extracted rare earth continually,the organic and aqueous phase formed emulsification easily.

冻融循环及各向异性对原状黄土动力特性的影响研究

【目的】为了研究冻融循环作用和各向异性对西宁地区原状黄土力学特性及变形的影响,【方法】借助冻融循环试验箱和GDS双向动态三轴仪,开展冻融循环试验和施加半正弦波形式的循环荷载动力特性试验,采用修正H-D模型分析冻融循环次数、与沉积方向呈不同角度对西宁地区黄土动力特性参数的影响。【结果】结果显示:(1)随着冻融循环次数的增加,动剪切强度呈现出先减小后增加的趋势;黄土Gd-1增长阈值呈现出先增大后减小的趋势;黄土阻尼比λ呈现出先增加后减小的趋势。(2)与沉积方向呈不同角度的土样动剪切强度具有差异性,即由大到小为0°>60°>90°>45°;Gd-1增长阈值由大到小为45°>90°>60°>0°;黄土阻尼比λ由大到小为45°>90°>60°>0°。【结论】结果表明:(1)随着冻融循环次数的增加,土体结构强度和刚度均表现出先减弱后增强的趋势,土体抵抗变形消耗的动能则呈相反趋势。(2)各向异性影响黄土的动剪切强度、刚度及阻尼比,与沉积方向呈45°土体动剪切强度最低,刚度最弱,土体发生变形消耗动能最多。(3)冻融循环作用影响土体在不同方向的力学特性,随冻融循环次数的增加,与沉积方向呈45°时土体各向异性表现明显,其结构损伤程度最大。

一种改进的小样本医学图像分割算法研究

文章针对医学图像的小样本特点和分割模型泛化能力差的问题,提出了一种基于元学习的医学图像分割网络。文章首先在3D U-Net网络基础上,将其下采样模块从两层三维卷积层增加为三层,将每层三维卷积层的批归一化改进为组归一化;其次在U型网络编解码器连接处,引入Transformer模块,增强模型提取全局信息的能力;在U型网络跳跃连接处引入了改进的注意力门机制,原理是替换其中的批归一化改进为组归一化,优化使用低批次来训练模型的效果,将Softmax激活函数替换为ReLU激活函数;最后使用模型无关元学习(Model Agnostic Meta Learning,MAML)算法训练模型。在公开数据集M&Ms上的实验结果表明,文章算法的Dice评分和Hausdorff距离分别为69.9%和11.88 mm,与其他主流算法对比,分割精度更优,泛化能力更好。

基于SBERT-Attention-LDA与ML-LSTM特征融合的烟草问句意图识别方法

针对烟草领域中问句意图识别存在的特征稀疏、术语繁多和捕捉文本内部的语义关联困难等问题,提出了一种基于SBERT-Attention-LDA(Sentence-bidirectional encoder representational from transformers-Attention mechanism-Latent dirichlet allocation)与ML-LSTM(Multi layers-Long short term memory)特征融合的问句意图识别方法。该方法首先基于SBERT预训练模型和Attention机制对烟草问句进行动态编码,转换为富含语义信息的特征向量,同时利用LDA模型建模出问句的主题向量,捕捉问句中的主题信息;然后通过更改后的模型级特征融合方法ML-LSTM获得具有更为完整、准确问句语义的联合特征表示;再使用3通道的卷积神经网络(Convolutional neural network,CNN)提取问句混合语义表示中隐藏特征,输入到全连接层和Softmax函数中实现对问句意图的分类。基于烟草行业权威网站上获取的数据集开展了实验验证,实验结果表明,所提方法相比其他几种深度学习结合注意力机制的方法精确率、召回率和F1值上有显著提升,与BERT和ERNIE(Enhanced representation through knowledge integration and embedding)-CNN模型相比提升明显,F1值分别提升2.07、2.88个百分点。

海上风电大直径嵌岩单桩侧向承载机理分析

针对我国海上风电基础的大量嵌岩需求,文章采用物理模型试验及数值模拟方法研究了大直径嵌岩单桩基础的水平受荷特性以及桩-岩整体失效模式,分析了基岩强度、桩基直径、桩基壁厚、嵌岩深度等因素对嵌岩桩侧向承载性能的影响。研究结果表明:桩身抗弯能力随基岩强度提高而提高;嵌岩桩基础浅层基岩的破坏遵循被动楔形破坏模式,深层基岩的破坏遵循旋转破坏模式;基岩强度、桩基直径和嵌岩深度的增加均能提高桩基水平承载力,而桩基壁厚对其影响不大;对于嵌岩桩水平承载性能的提升效果存在临界嵌岩深度,桩径及覆盖层厚度对临界嵌岩深度的影响较小,而基岩强度对其变化较为敏感。