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Effects of Al_(2)O_(3)-SiO_(2) Raw Material Types on Properties of Anorthite Based Insulation Refractories

China's Refractories 2024年第1期33卷 23-27页

作者： DU Juan GUO Huishi YANG Jialin li Wenfeng GUI Yanghai ZHAO Zhiqiang liU Yingfan School of Materials Science and Engineering Henan University of TechnologyZhengzhou 450001China School of Materials and Chemical Engineering Zhengzhou University of Light IndustryZhengzhou 450051China

To optimize their Al_(2)O_(3)-SiO_(2) raw materials,anorthite based insulation refractories were prepared by the in-situ sintering process combined with the foaming method after sintering at 1.50℃for 3 h,using green and pollution-free kaolin,kyanite,andalusite and sillimanite as Al_(2)O_(3)-SiO_(2) raw materials,respectively,and industrial CaCO_(3) as the CaO *** of Al_(2)O_(3)-SiO_(2) raw material types on the physical properties,phase composition and microstructure were *** results are as *** samples prepared by different Al_(2)O_(3)-SiO_(2) raw materials have hexagonal flake anorthite and a small amount of mullite and *** bulk density and thermal conductivity decrease in the order of using kaolin,andalusite,kyanite and sillimanite as the Al_(2)O_(3)-SiO_(2) raw material,but their apparent porosity ***,in the sample with kaolin,the bonding between anorthite crystals on the pore walls is closer than that of the other samples,which is conducive to increasing the cold crushing *** bonding between anorthite crystals on pore walls gradually decreases in the order of using kyanite,andalusite and sillimanite as the Al_(2)O_(3)-SiO_(2) raw material,thus their cold crushing strength decreases *** comprehensive consideration,the properties of the sample from kyanite are the *** apparent porosity,thermal conductivity and cold crushing strength are 84.6%,0.1.1.W·m^(-1.·K^(-1. and 1.89 MPa,respectively.

关键词： anorthite based insulation refractories Al_(2)O_(3)-SiO_(2)raw materials crushing strength thermal conductivity microstructure

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Residue behaviors and dietary risk assessment of dinotefuran and its metabolites in Lycium barbarum from farm to fork

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Food Science and Human Wellness 2024年

作者： Ouli Xiao Minmin li Jieyin Chen Ran Wang Xiaofeng Dai Zhiqiang Kong State Key Laboratory for Biology of Plant Diseases and Insect Pests， Institute of Plant Protection， Chinese Academy of Agricultural Sciences Western Agricultural Research Center， Chinese Academy of Agricultural Sciences Key Laboratory of Agro-products Quality and Safety Control in Storage and Transport Process， Ministry of Agriculture and Rural Affairs/Institute of Food Science and Technology， Chinese Academy of Agricultural Sciences Institute of Plant Protection， Beijing Academy of Agriculture and Forestry Sciences

Lycium barbarum， known as wolfberry or goji berry， is consumed by humans as a medicine and a food homology product. Conventionally grown wolfberry is often treated extensively with pesticides， which could pose a hazard to humans. Here， the degradation dynamics of dinotefuran and its two metabolites (UF and DN)， during wolfberry cultivation and processing was investigated. The half-life (T1.2) of dinotefuran was 1..36 d and 9.1. d， respectively， under the recommended dosage and double the recommended dosage. During the oven and sun drying processes， processing factors (PFs) of dinotefuran were 1.07 - 1.34， implying the enrichment of pesticide residues. Decoction process made the removal rate of dinotefuran reach 87.48%， which is higher than that of the brewing process (1..7%)， while dinotefuran remained in the wine with high ethanol content in the alcohol soaking process. The hazard quotient (HQ) of dinotefuran， as determined via dietary risk assessment combined with PFs， was 1. indicating an acceptable risk for human consumption. Bioaccessibility of dinotefuran in the three digestive stages were intestinal (1..20% - 88.08%) > gastric (5.45% - 86.72%) > oral (23.1.%) via in vitro simulated digestive system. These findings provide scientific evidence for reasonable application and risk assessment of dinotefuran residues in wolfberry.

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搭载给水管的宽幅流线型钢箱梁涡振性能及抑振措施研究

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振动与冲击 2024年第4期43卷 199-206,238页

作者：李春光李赫佳陈赛韩艳长沙理工大学土木工程学院湖南长沙410114

为研究给水管不同设置位置对宽幅流线型钢箱梁的涡振性能影响及涡振抑制措施,以某大跨度扁平钢箱梁斜拉桥为研究对象,制作缩尺比为1.50的钢箱梁刚性节段模型进行风洞试验和数值模拟计算。首先对比分析了风攻角为0°、±3°时,给水管设... 详细信息

为研究给水管不同设置位置对宽幅流线型钢箱梁的涡振性能影响及涡振抑制措施,以某大跨度扁平钢箱梁斜拉桥为研究对象,制作缩尺比为1.50的钢箱梁刚性节段模型进行风洞试验和数值模拟计算。首先对比分析了风攻角为0°、±3°时,给水管设置在主梁风嘴内(Ⅰ型)和设置在桥面上(Ⅱ型)两种不同断面形式的主梁涡振特性;并采用数值模拟探究了给水管对主梁涡振性能影响的作用机理。其次,研究了结构阻尼比对Ⅰ型断面主梁涡振性能的影响;最后,通过试验测试了栏杆透风率、栏杆抑流板等气动措施对Ⅰ型断面主梁涡振性能的影响。试验结果表明:给水管是涡振敏感构件,对于Ⅰ型断面,风攻角为-3°时,主梁未出现涡振现象;风攻角为0°时,有小幅涡振响应;风攻角为+3°时,出现明显的涡振现象;Ⅱ型断面主梁无涡振现象发生。数值模拟结果显示,给水管放置在主梁外部可以有效降低上表面旋涡的尺寸,从而抑制涡振的产生。增大结构阻尼比可以有效抑制主梁的涡振;改变栏杆透风率抑振效果不明显;设置抑流板对抑振效果明显。

关键词：给水管涡振性能风洞试验数值模拟气动措施阻尼比抑流板栏杆

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Impact of fluorine on crystal-melt separation in high-silica magma: Insights from muscovite in the Ramba leucogranite of Tethyan Himalaya

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Journal of Earth Science 2024年

作者： li-Ran Chen Wang-Chun Xu lian-Xun Wang Hong-Fei Zhang Wuhan State Key Laboratory of Geological Processes and Mineral Resources， and School of Earth Sciences， China University of Geosciences

The process of crystal-melt separation in the high-silica magmatic mush is still a subject of debate. To explore the process， we conducted a detailed study of Late Miocene leucogranites (SiO2＞70 wt.%) in the Ramba Dome of the Tethyan Himalaya， focusing on the genesis and fluorine content of muscovite. The Ramba leucogranites consist of two-mica granite with minor garnet-bearing granite. Large and euhedral muscovites are found in both types of granite exhibiting different geochemical features. The muscovites from the two-mica granites exhibit lower F (mean value: ～0.41.0.43 wt.%)， FeO (mean value: ～1.75–1.81.wt.%)， but higher TiO2(mean value: ～0.61.0.73 wt.%) contents compared to those from the garnet-bearing granites (mean F value: ～0.72%; mean FeO value: 2.48 wt.%; mean TiO2value: ～0.23 wt.%). According to geochemical criteria， we categorized the muscovites from the two-mica granite as two groups: (1. crystallized from the early magma， and (2) formed from interstitial residual melt. In comparison， the muscovite from the garnet-bearing granite was likely crystallized from residual melt extracted from the same magmatic reservoir which underwent a higher degree of evolution. Accordingly， the two-mica granite represents the residual crystal mush consisting of early crystals crystallized from magma and trapped interstitial residual melt， while the garnet-bearing granite represents the aggregation of extracted residual melt. We examined the possibility of crystal-melt separation by estimating the variation of fluorine content and viscosity between the early magma and residual melt. Our results indicate a notable disparity in fluorine content between the residual melt (mean value: ～4364 ppm) and the early magma (mean value: ～2033 ppm). As a result， the estimated viscosity experiences a reduction from 1.6.52Pa s for the early magma to 1.5.87Pa s for the residual melt. The fluorine enrichment could have played a critical role in decreasing melt viscosity and initiating crys

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市场一体化对黄河流域经济高质量发展的影响

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资源科学 2024年第3期46卷 462-474页

作者：生延超李金婧徐珊李倩湖南工商大学公共管理与人文地理学院长沙410205 浙江工业大学管理学院杭州310014

[目的]加快建设统一大市场是落实黄河流域生态保护和高质量发展战略的重要推手,研究市场一体化对黄河流域经济高质量发展的影响及机制,可为黄河流域经济高质量发展提供理论支撑和政策参考。[方法]选取201.-2020年黄河流域的69个地级市... 详细信息

[目的]加快建设统一大市场是落实黄河流域生态保护和高质量发展战略的重要推手,研究市场一体化对黄河流域经济高质量发展的影响及机制,可为黄河流域经济高质量发展提供理论支撑和政策参考。[方法]选取201.-2020年黄河流域的69个地级市的面板数据作为样本,利用双向固定效应模型、中介模型和门槛模型探讨市场一体化对黄河流域经济高质量发展的影响。[结果]①市场一体化能够显著促进黄河流域经济高质量发展,市场一体化程度每提升1.单位,黄河流域经济高质量发展水平提升0.579个单位。②完善基础设施、要素流动和产业结构升级是市场一体化促进黄河流域经济高质量发展的重要机制。③经济集聚存在显著的单一门槛效应,当经济集聚程度超过门槛值0.020,市场一体化对黄河流域经济高质量发展的促进作用降低。④市场一体化对黄河流域经济高质量发展的促进作用存在区域异质性,中小城市市场一体化对其经济高质量发展的促进作用更强烈,特大城市市场一体化抑制其经济高质量发展。[结论]要加快推进黄河流域市场一体化建设,完善地区基础设施,畅通要素流动,促进产业结构升级,合理控制经济集聚程度和城市规模,借助政策因地制宜发挥市场一体化的高质量红利效应。

关键词：市场一体化经济高质量发展基础设施要素流动产业结构升级黄河流域

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Molecular-scale co-assembly membranes derived from keplerate cluster:carbonic anhydrase-mimicking nanocapsules for enhanced CO/Nseparation

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Science China Chemistry 2024年

作者： Wanlei Zhao Hongqiang li Ruoxuan Zheng Yixin Yang Wei Chen Yufei Song State Key Laboratory of Chemical Resource Engineering Beijing University of Chemical Technology Quzhou Institute for Innovation in Resource Chemical Engineering

The development of CO2separation membranes with high permeability and high selectivity,as well as ultra-thin selective layers,has always been ***,a molecular-scaled co-assembly strategy is employed to fabricate the Pebax-Mo1.2(Pebax=polyether-block-amide copolymer;Mo1.2=（NH4）42[Mo72VIMo60VO372（CH3COO）30（H2O）72]) *** optimal selfstanding membrane,Pebax-Mo1.2-5%,shows a CO2permeability of～384 Barrer and an ultra-high ideal CO2/N2selectivity of～244,outperforming most membranes reported in the *** CO2permeability and ideal CO2/N2selectivity are increased by 70%and 367%,respectively,compared with the pristine Pebax membrane.A thin-film composite membrane prepared by spin-coating technique on a support membrane with gutter layers also exhibits a CO2permeance of 838 GPU and a CO2/N2selectivity of *** excellent performance can be attributed to the following reasons:（1. strong hydrogen bonding interactions between{Mo1.2}clusters and Pebax confer excellent interfacial compatibility to the mixed matrix membranes;（2）incorporation of hollow{Mo1.2}clusters into the Pebax molecular chain decreases the crystallinity of Pebax,and thereby accelerates the chain dynamics and increases the free volume of the membrane;（3） in situ diffuse reflectance infrared Fouriertransform spectroscopy demonstrates that the{Mo1.2}clusters can effectively catalyze the hydration reaction of CO2and promote the transport of CO2;（4） furthermore,the 0.35 nm pores of the crown ether-type{Mo9O9}allow the accurate size sieving of CO2（0.33 nm） and N2（0.36 nm） molecules.

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基于有约束L_(1.2)范数稀疏正则化的声源识别方法

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振动与冲击 2024年第2期43卷 166-178页

作者：潘薇李远文冯道方黎敏北京科技大学钢铁共性技术协同创新中心北京100083 北京科技大学流体与材料相互作用教育部重点实验室北京100083 北京科技大学机械工程学院北京100083

基于等效源法(equivalent source method,ESM)的近场声全息(near field acoustic holography,NAH)是一种有效的声源识别技术。然而,针对空间稀疏分布的声源识别问题,传统基于L_(2)范数以及基于L_(1.范数的ESM方法分别存在声源幅值被低... 详细信息

基于等效源法(equivalent source method,ESM)的近场声全息(near field acoustic holography,NAH)是一种有效的声源识别技术。然而,针对空间稀疏分布的声源识别问题,传统基于L_(2)范数以及基于L_(1.范数的ESM方法分别存在声源幅值被低估与算法稳定性差等问题。因此,提出了基于有约束L_(1.2)范数稀疏正则化的声源识别方法,该方法具有强稀疏性与强抗干扰的优势,可以解决传统方法的声源识别精度低的问题。通过数值模拟试验以及普通室内的实测实验,验证了方法的有效性。

关键词：声源识别等效源法(ESM) 有约束L_(1.2)范数稀疏正则化

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政府在应急管理中采取的避责策略生成机理研究——基于不完全契约理论的分析

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湘潭大学学报（哲学社会科学版） 2024年第3期48卷 14-20页

作者：李立清李若涛湖南农业大学公共管理与法学学院湖南长沙410128

避责策略作为一种趋利避害的倾向普遍存在于政府决策者中,阻碍了政府的应急管理效能提升。本文运用单案例分析,借助不完全契约理论,提出“应急管理‘控制权—索取权’避责策略生成机理分析框架”,以“H省C市特别重大居民自建房倒塌事故... 详细信息

避责策略作为一种趋利避害的倾向普遍存在于政府决策者中,阻碍了政府的应急管理效能提升。本文运用单案例分析,借助不完全契约理论,提出“应急管理‘控制权—索取权’避责策略生成机理分析框架”,以“H省C市特别重大居民自建房倒塌事故”为案例,对政府在应急管理中采取的避责策略生成机理进行分析。研究发现:(1.公共权力分配机制缺陷与风险不确定性的存在,驱动了政府采取应急管理避责策略;(2)监督机制失灵催生下级政府过度扩张剩余索取权;(3)上级政府剩余控制权过强将挫败下级政府应急管理积极性。本文据此提出相应政策建议:(1.改进权力分配机制;(2)完善权力监督机制;(3)优化绩效评估体系。

关键词：避责策略生成机理不完全契约理论

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组合浸渍和超低温冻融预处理对真空冷冻干燥蓝莓品质的影响

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农业工程学报 2024年第2期40卷 82-92页

作者：李洋李国庆袁迪郑梓仪东北林业大学土木与交通学院哈尔滨150040

为探究组合浸渍冻干保护剂(海藻糖-CaCl_(2))和超低温冻融预处理对蓝莓活性物质和品质的影响,该研究以直接冷冻干燥为对照组,以普通冻融(-20℃)、超低温快速冻融(-80℃)、超声波辅助冻干保护剂浸渍冻融(-20℃)、(-80℃)预处理后进行真... 详细信息

为探究组合浸渍冻干保护剂(海藻糖-CaCl_(2))和超低温冻融预处理对蓝莓活性物质和品质的影响,该研究以直接冷冻干燥为对照组,以普通冻融(-20℃)、超低温快速冻融(-80℃)、超声波辅助冻干保护剂浸渍冻融(-20℃)、(-80℃)预处理后进行真空冷冻干燥为试验组,比较分析蓝莓活性物质(多酚氧化酶和过氧化物酶活性)、营养物质(维生素C、花青素、总酚、类黄酮)、质构特性(硬度、咀嚼性)等指标的变化情况,并在此基础上进行BoxBehnken三因素三水平试验设计。结果表明:单一的冻干保护剂浸渍处理或者超低温处理均不如两者组合效果理想,两者组合浸渍后-80℃冻融处理可以有效维持蓝莓硬度,提高蓝莓营养物质的保留度并减少真空冷冻干燥时间。冻融次数为2次,浸渍时间为3.7 h,单次冷冻时间为4.2 d时蓝莓综合指标最高,营养物质保留度最高。该研究阐述了冻干保护剂浸渍预处理与超低温冻融两者联合处理对真空冷冻干燥蓝莓品质提升的机理,探究了冻融次数、冷冻时间、浸渍时间对品质的影响,得出了真空冷冻干燥预处理的最佳参数,为蓝莓真空冷冻干燥技术的发展提供了新思路。

关键词：蓝莓冻融超低温冻干保护剂超声波浸渍

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The microbial community and flavour substances of off-flavoured rice sour soup during storage

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Food Science and Human Wellness 2024年

作者： Xiuli li Na liu likang Qin Ting Zhu Ruyue Xiao Song Miao School of liquor and Food Engineering， Gui{1. University Majiang Mingyang Foods Co. Teagasc Food Research Centre， Moorepark， Fermoy， Co.Cork

Fermented sour soup is a unique traditional sour food of the Miao and Dong ethnic groups in China. However， due to the commonly used traditional fermentation， the unstable fluctuation of microbial community often leads to some unpleasant inherent off-flavours in rice sour soup. In this study， the microbial composition and volatile flavour components of off-flavour and normal rice sour soup were examined by high-throughput sequencing (HTS) and headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry (HS-SPME-GC-MS). Then， based on Pearson correlation coefficients， the correlations between fungi and bacteria and those between core microorganisms and key volatile flavour components were investigated. The dominant fungal genera included Candida， Dekkera， Pichia， Rhizopus， and Issatchenkia， whereas the dominant bacterial genera included Lactobacillus， Pectinatus， Bifidobacterium， Pseudomonas， and Acetobacter. Compared to normal rice sour soup， off-flavoured rice sour soup contained the significantly increased relative abundance of Candida and the significantly decreased relative abundance of Dkkera. In addition， 80 volatile flavour compounds detected in off-flavoured rice sour soup， mainly including esters， acids， and alcohols， were different from those detected in normal rice sour soup. Especially， some substances were only detected in off-flavoured rice sour soup， such as 1.hexanol (68-207 μg/kg)， butyric acid (20-91.μg/kg) and heptanoic acid (1.-44 μg/kg)， which might be the main source of off-flavours. These results provide new ideas and strategies of removing or abating odour from fermented rice sour soup.

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