检索结果-南通市图书馆

Corrosion Resistance and Tribological Properties of Laser Cladding Layer of H13 Die Steel Strengthened by Ultrasonic Rolling

引用

Chinese Journal of Mechanical Engineering 2022年第6期35卷 415-426页

作者： Kaikui Zheng youxi lin Jianguo Cai Chengqian Lei School of Mechanical Engineering and Automation Fuzhou UniversityFuzhou 350116China School of Advanced Manufacturing Fuzhou UniversityJinjiang 362251China Mechanical and Electrical Engineering Practice Center Fuzhou UniversityFuzhou 350116China

Laser cladding is a new surface repair method that can improve the wear and corrosion resistance of substrate surfaces.However,the cladding layer typically exhibits a rough surface,high hardness and large residual tensile stress,and thus requires further machining and finishing.Ultrasonic rolling(U-rolling)is a highly efficient finishing and strengthening process that combines ultrasonic technology with traditional rolling(T-rolling).In this study,an ironbased alloy was coated onto the surface of H13 die steel using laser cladding,and the surface of the cladding layer was polished using U-rolling.The effects of U-rolling on the surface quality,corrosion resistance and friction and wear properties of the laser-cladding layer were investigated and compared with those obtained by T-rolling.The surface roughness of the U-rolled sample was only 1/4 that of the T-rolled sample.The hardness and residual compressive stress of the laser cladding layer after U-rolling were higher than those after T-rolling.Similarly,the surface corrosion resistance of the laser cladding layer after U-rolling was higher than that after T-rolling.U-rolling changed the surface roughness,grain size,and residual stress of the material and thus affected the corrosion resistance of the laser cladding layer.The friction coefficient and wear rate of the U-rolled surface of the cladding layer were lower than those of the T-rolled surface.In addition,the tribological properties of the cladding layer were found to be related to the rolling direction.When the friction direction of the sample was the same as the rolling direction,its friction and wear performance were higher than those when the two directions were perpendicular.

关键词： Laser cladding Ultrasonic rolling Surface quality Corrosion resistance Tribological properties

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Dry friction damping mechanism of flexible microporous metal rubber based on cell group energy dissipation mechanism

引用

Friction 2023年第2期11卷 259-279页

作者： Liangliang SHEN Zhiying REN Jian XU lin PAN youxi lin Hongbai BAI School of Mechanical Engineering and Automation Fuzhou UniversityFuzhou 350116China Engineering Research Center for Metal Rubber Fuzhou UniversityFuzhou 350116China State Key Laboratory of Fine Chemicals Liaoning High Performance Polymer Engineering Research CenterSchool of Chemical EngineeringDalian University of TechnologyDalian 116024China Fuzhou Friction and Lubrication Industry Technology Innovation Center Fuzhou 350108China

Flexible microporous metal rubber (FMP-MR) is a high-damping material that dissipates energy by dry friction through internal spiral metal wires in contact with each other. However, the FMP-MR energy dissipation mechanism is not fully understood owing to its disordered grid interpenetrating structure. In this work, computer-aided preparation technology is used to accurately reconstruct the complex spiral network structure of FMP-MR multipoint random contact, and a cell group model with an energy dissipation mechanism is proposed to obtain the dynamic energy distribution of the contact friction in both space and time dimensions. By judging the effective contact point, a global displacement ablation phenomenon of hooked staggered porous materials is induced. The macro- and micro-equivalent frictions are introduced to effectively explain the characteristics of the strong energy dissipation in FMP-MR under fretting excitation. A real and effective damping hysteresis constitutive model is then constructed to dynamically capture the mapping relationship between the complex nonlinear topological structure effect of the materials and spatial random contact dry friction in real time. The results indicate that the contact behavior between turns of the FMP-MR wire follows a clear quasi-Gaussian distribution under an external load, forcing the topological results to change. The energy dissipation of the materials revealed peak energy consumption lagging behind the loading limit for a certain distance, which can be determined by the effective contact point and contact dry friction slip. The consistency between the quasi-static compression tests and constitutive curves of the model was quantitatively verified through residual analysis. The data demonstrated the differential behavior of the FMP-MR meso-structure to follow a phased growth law during loading with different action mechanisms in the guiding, main growth, and relaxation stages of the energy consumption displacement curve. In summary, these findings provide an accept

关键词： flexible microporous metal rubber(FMP-MR) effective contact energy dissipation dry friction damping hysteresis

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

VOC emitted by biopharmaceutical industries:Source profiles,health risks,and secondary pollution

引用

Journal of Environmental Sciences 2024年第1期135卷 570-584页

作者： Jiawei Ma lin Li State Key Laboratory of Environmental Aquatic Chemistry Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijing 100085China University of Chinese Academy of Sciences Beijing 100049China National Engineering Laboratory for VOCs Pollution Control Material&Technology University of Chinese Academy of SciencesBeijing 101408China

The biopharmaceutical industry contributes substantially to volatile organic compounds(VOCs)emissions,causing growing concerns and social developmental conflicts.This study conducted an on-site investigation of the process-based emission of VOCs from three biopharmaceutical enterprises.In the workshops of the three enterprises,26 VOCs were detected,which could be sorted into 4 classes:hydrocarbons,aromatic hydrocarbons,oxygen-containing compounds,and nitrogen-containing compounds.Ketones were the main components of waste gases,accounting for 44.13%-77.85%of the overall VOCs.Process-based source profiles were compiled for each process unit,with the fermentation and extraction units of tiamulin fumarate being the main source of VOC emissions.Dimethyl heptanone,vinyl acetate,diethylamine,propylene glycol methyl ether(PGME),and benzene were screened as priority pollutants through a fuzzy comprehensive evaluation system.Ground level concentration simulation results of the Gauss plume diffusion model demonstrated that the diffusivity of VOCs in the atmosphere was relatively high,indicating potential non-carcinogenic and carcinogenic risks 1.5-2 km downwind.Furthermore,the process-based formation potentials of ozone and secondary organic aerosols(SOAs)were determined and indicated that N-methyl-2-pyrrolidone,dimethyl heptanone,and PGME should be preferentially controlled to reduce the ozone formation potential,whereas the control of benzene and chlorobenzene should be prioritized to reduce the generation of SOAs.Our results provide a basis for understanding the characteristics of VOC emission by biopharmaceutical industries and their diffusion,potentially allowing the development of measures to reduce health risks and secondary pollution.

关键词： Biopharmaceutical Volatile organic compound Priority pollutant Exposure risk Secondary pollution

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Construction of algal-bacterial consortia using green microalgae Chlorella vulgaris and As(Ⅲ)-oxidizing bacteria:As tolerance and metabolomic profiling

引用

Journal of Environmental Sciences 2024年第5期139卷 258-266页

作者： Xiaoman He Guobing lin Jiayuan Zeng Zhaoguang Yang lin Wang College of Chemistry and Chemical Engineering Central South UniversityChangsha 410083China Key Laboratory of Hunan Province for Water Environment and Agriculture Product Safety Central South UniversityChangsha 410083China

Bioremediation became a promising technology to resolve arsenic(As)contamination in aquatic environment.Since monoculture such as microalgae or bacteria was sensitive to environmental disturbance and vulnerable to contamination,green microalgae Chlorella vulgaris and arsenite(As(Ⅲ))-oxidizing bacteria Pseudomonas sp.SMS11 were co-cultured to construct algal-bacterial consortia in the current study.The effects of algae-bacteria(A:B)ratio and exposure As(Ⅲ)concentration on algal growth,As speciation and metabolomic profile were investigated.Algal growth arrested when treated with 100 mg/L As(Ⅲ)without the co-cultured bacteria.By contrast,co-cultured with strain SMS11 significantly enhanced As tolerance in C.vulgaris especially with A:B ratio of 1:10.All the As(Ⅲ)in culture media of the consortia were oxidized into As(Ⅴ)on day 7.Methylation of As was observed on day 14.Over 1% and 0.5% of total As were converted into dimethylarsinic acid(DMA)after 21days cultivation when the initial concentrations of As(Ⅲ)were 1 and 10 mg/L,respectively.Metabolomic analysis was further performed to reveal the response of consortia metabolites to external As(Ⅲ).The enriched metabolomic pathways were associated with carbohydrate,amino acid and energy metabolisms.Tricarboxylic acid cycle and glyoxylate and dicarboxylate metabolism were upregulated under As stress due to their biological functions on alleviating oxidative stress and protecting cells.Both carbohydrate and amino acid metabolisms provided precursors and potential substrates for energy production and cell protection under abiotic stress.Alterations of the pathways relevant to carbohydrate or amino acid metabolism were triggered by energy requirement.

关键词： Microalgae Algal-bacterial consortia As(Ⅲ)-oxidizing bacteria Metabolomics Energy metabolism

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

A fast forward computational method for nuclear measurement using volumetric detection constraints

引用

Nuclear Science and Techniques 2024年第2期35卷 47-63页

作者： Qiong Zhang lin-Lv lin University of Electronic Science and Technology of China Chengdu 610000China

Owing to the complex lithology of unconventional reservoirs,field interpreters usually need to provide a basis for interpretation using logging simulation models.Among the various detection tools that use nuclear sources,the detector response can reflect various types of information of the medium.The Monte Carlo method is one of the primary methods used to obtain nuclear detection responses in complex environments.However,this requires a computational process with extensive random sampling,consumes considerable resources,and does not provide real-time response results.Therefore,a novel fast forward computational method(FFCM)for nuclear measurement that uses volumetric detection constraints to rapidly calculate the detector response in various complex environments is proposed.First,the data library required for the FFCM is built by collecting the detection volume,detector counts,and flux sensitivity functions through a Monte Carlo simulation.Then,based on perturbation theory and the Rytov approximation,a model for the detector response is derived using the flux sensitivity function method and a one-group diffusion model.The environmental perturbation is constrained to optimize the model according to the tool structure and the impact of the formation and borehole within the effective detection volume.Finally,the method is applied to a neutron porosity tool for verification.In various complex simulation environments,the maximum relative error between the calculated porosity results of Monte Carlo and FFCM was 6.80%,with a rootmean-square error of 0.62 p.u.In field well applications,the formation porosity model obtained using FFCM was in good agreement with the model obtained by interpreters,which demonstrates the validity and accuracy of the proposed method.

关键词： Nuclear measurement Fast forward computation Volumetric constraints

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

面向阵列级同时同频收发的宽带自干扰空域抑制

引用

电子与信息学报 2024年第5期46卷 1951-1957页

作者：林朗赵宏志邵士海唐友喜电子科技大学通信抗干扰全国重点实验室成都611731 电磁空间认知与智能控制技术实验室北京100089

具备阵列级同时同频收发能力的多功能一体化平台,面临发射阵列对接收阵列的强自干扰问题。针对这一问题,该文设计了一种宽带自干扰空域抑制方法,构造了限制主波束增益损失条件下,最小化残余自干扰和噪声功率的非凸优化问题,提出了交替... 详细信息

具备阵列级同时同频收发能力的多功能一体化平台,面临发射阵列对接收阵列的强自干扰问题。针对这一问题,该文设计了一种宽带自干扰空域抑制方法,构造了限制主波束增益损失条件下,最小化残余自干扰和噪声功率的非凸优化问题,提出了交替迭代的优化算法联合求解发射和接收数字波束成形系数,从理论上分析了所提算法的自干扰抑制极限性能,并给出了所提算法的计算复杂度。分析和仿真结果表明,给定2.4 GHz工作频率,100 MHz带宽,主波束增益损失限制在3 dB时,收发各30阵元的相控阵列宽带自干扰空域抑制能力,即有效各向同性隔离度达到168 dB,距离自干扰抑制性能极限差距7 dB。

关键词：同时同频收发数字波束成形空域自干扰抑制

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

The physiological role of the unfolded protein response in the nervous system

引用

Neural Regeneration Research 2024年第11期19卷 2411-2420页

作者： Shuangchan Wu Wensheng lin Department of Neuroscience University of MinnesotaMinneapolisMNUSA Institute for Translational Neuroscience University of MinnesotaMinneapolisMNUSA

The unfolded protein response(UPR)is a cellular stress response pathway activated when the endoplasmic reticulum,a crucial organelle for protein folding and modification,encounters an accumulation of unfolded or misfolded proteins.The UPR aims to restore endoplasmic reticulum homeostasis by enhancing protein folding capacity,reducing protein biosynthesis,and promoting protein degradation.It also plays a pivotal role in coordinating signaling cascades to determine cell fate and function in response to endoplasmic reticulum stress.Recent research has highlighted the significance of the UPR not only in maintaining endoplasmic reticulum homeostasis but also in influencing various physiological processes in the nervous system.Here,we provide an overview of recent findings that underscore the UPR’s involvement in preserving the function and viability of neuronal and myelinating cells under physiological conditions,and highlight the critical role of the UPR in brain development,memory storage,retinal cone development,myelination,and maintenance of myelin thickness.

关键词： myelin neuron oligodendrocyte Schwann cell unfolded protein response

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

NFXL1 functions as a transcriptional activator required for thermotolerance at reproductive stage in Arabidopsis

引用

Journal of Integrative Plant Biology 2024年第1期66卷 54-65页

作者： Qiao‐Yun Zhu lin‐lin Zhang Jian‐Xiang Liu State Key Laboratory of Plant Environmental Resilience College of Life SciencesZhejiang UniversityHangzhou 310027China

Plants are highly susceptible to abiotic stresses,particularly heat stress during the reproductive stage.However,the specific molecular mechanisms underlying this sensitivity remain largely unknown.In the current study,we demonstrate that the Nuclear Transcription Factor,X-box Binding Protein 1-Like 1(NFXL1),directly regulates the expression of DEHYDRATION-RESPONSIVE ELEMENT-BINDING PROTEIN 2A(DREB2A),which is crucial for reproductive thermotolerance in Arabidopsis.NFXL1 is upregulated by heat stress,and its mutation leads to a reduction in silique length(seed number)under heat stress conditions.RNA-Seq analysis reveals that NFXL1 has a global impact on the expression of heat stress responsive genes,including DREB2A,Heat Shock Factor A3(HSFA3)and Heat Shock Protein 17.6(HSP17.6)in flower buds.Interestingly,NFXL1 is enriched in the promoter region of DREB2A,but not of either HSFA3 or HSP17.6.Further experiments using electrophoretic mobility shift assay have confirmed that NFXL1 directly binds to the DNA fragment derived from the DREB2A promoter.Moreover,effector-reporter assays have shown that NFXL1 activates the DREB2A promoter.The DREB2A mutants are also heat stress sensitive at the reproductive stage,and DEREB2A is epistatic to NFXL1 in regulating thermotolerance in flower buds.It is known that HSFA3,a direct target of DREB2A,regulates the expression of heat shock proteins genes under heat stress conditions.Thus,our findings establish NFXL1 as a critical upstream regulator of DREB2A in the transcriptional cassette responsible for heat stress responses required for reproductive thermotolerance in Arabidopsis.

关键词： Arabidopsis DREB2A heat stress NFXL1 reproductive thermotolerance

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Emerging role of lncRNAs as mechanical signaling molecules in mechanotransduction and their association with Hippo-YAP signaling:a review

引用

Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2024年第4期25卷 280-292页

作者： Siyi lin Xinyu HE Ying WANG Yu CHEN Aifu lin College of Medicine Zhejiang UniversityHangzhou 310058China College of Life Sciences Zhejiang UniversityHangzhou 310058China Cancer Center Zhejiang UniversityHangzhou 310058China Key Laboratory for Cell and Gene Engineering of Zhejiang Province Hangzhou 310058China International School of Medicine International Institutes of Medicinethe Fourth Affiliated Hospital of Zhejiang University School of MedicineYiwu 322000China Key Laboratory of Cancer Prevention and Intervention China National Ministry of EducationHangzhou 310058China Future Health Laboratory Innovation Center of Yangtze River DeltaZhejiang UniversityJiaxing 314100China

Cells within tissues are subject to various mechanical forces,including hydrostatic pressure,shear stress,compression,and tension.These mechanical stimuli can be converted into biochemical signals through mechanoreceptors or cytoskeleton-dependent response processes,shaping the microenvironment and maintaining cellular physiological balance.Several studies have demonstrated the roles of Yes-associated protein(YAP)and its homolog transcriptional coactivator with PDZ-binding motif(TAZ)as mechanotransducers,exerting dynamic influence on cellular phenotypes including differentiation and disease pathogenesis.This regulatory function entails the involvement of the cytoskeleton,nucleoskeleton,integrin,focal adhesions(FAs),and the integration of multiple signaling pathways,including extracellular signal-regulated kinase(ERK),wingless/integrated(WNT),and Hippo signaling.Furthermore,emerging evidence substantiates the implication of long non-coding RNAs(lncRNAs)as mechanosensitive molecules in cellular mechanotransduction.In this review,we discuss the mechanisms through which YAP/TAZ and lncRNAs serve as effectors in responding to mechanical stimuli.Additionally,we summarize and elaborate on the crucial signal molecules involved in mechanotransduction.

关键词： YAP/TAZ Long non-coding RNA(lncRNA) Mechanotransduction F-actin

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Comprehensive study on the spatial distribution of heavy metals and their environmental risks in high-sulfur coal gangue dumps in China

引用

Journal of Environmental Sciences 2024年第2期136卷 486-497页

作者： Yingbo Dong Huan Lu Hai lin School of Energy and Environmental Engineering University of Science and Technology BeijingBeijing 100083China Beijing Key Laboratory on Resource-oriented Treatment of Industrial Pollutants Beijing 100083China

The accumulation of coal gangue(CG)from coal mining is an important source of heavy metals(HMs)in soil.Its spatial distribution and environment risk assessment are extremely important for the management and remediation of HMs.Eighty soil samples were collected from the high-sulfur CG site in northern China and analyzed for six HMs.The results showed that the soil was heavily contaminated by Mn,Cr and Ni based on the Nemerow index,and posed seriously ecological risk depended on the geo-accumulation index,potential ecological risk index and risk assessment code.The semi-variogram model and ordinary kriging interpolation accurately portrayed the spatial distribution of HMs.Fe,Mn,and Cr were distributed by band diffusion,Ni was distributed by core,the distribution of Cu had obvious patchiness and Zn was more uniform.The spatial autocorrelation indicated that all HMs had strong spatial heterogeneity.The BCR sequential extraction was employed to qualify the geochemical fractions of HMs.The data indicated that Fe and Cr were dominated by residual fraction;Cu,Ni and Zn were dominated by reducible and oxidizable fractions;Mn was dominated by reducible and acid-extractable(25.38%-44.67%)fractions.Pearson correlation analysis showed that pH was the main control factor affecting the non-residue fractions of HMs.Therefore,acid production from high sulfur CG reduced soil pH by 2-3,which indirectly promoted the activity of HMs.Finally,the conceptual model of HMs contamination at the CG site was proposed,which can be useful for the development of ecological remediation strategies.

关键词： High-sulfur coal gangue Soil contamination Heavy metals Spatial distribution Geochemical fractions Risk assessment

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：