鲟鱼肝酶解条件优化及酶解液对双歧杆菌增殖效果的研究

为提高鲟鱼肝脏的加工附加值，使用碱性蛋白酶，以水解度为评价指标，在单因素试验的基础上，通过Plackett-Burman试验、响应面分析法优化鲟鱼肝蛋白酶解条件。在此条件下，进一步探究了酶解液对双歧杆菌的促生长效果。结果表明，最优酶解条件为碱性蛋白酶添加量10 540 U/g鱼肝蛋白、体系初始pH值10.0、酶解时间8.6 h、酶解温度45 ℃、料液比1∶10（g∶mL），此条件下水解度（81.7%）是优化前（40.4%）的1.02倍。鲟鱼肝蛋白酶解液对青春双歧杆菌、两歧双歧杆菌、动物双歧杆菌、长双歧杆菌、短双歧杆菌和婴儿双歧杆菌6种均具有显著的促生长效果。研究结果为鲟鱼加工副产物利用提供了新途径，同时也为双歧杆菌促生长因子的研发提供新思路。     

混炼方式对螺旋纳米碳纤维增强天然橡胶复合材料力学性能的影响

采用干法和湿法两种混炼工艺制备了螺旋纳米碳纤维(HCNFs)/炭黑(CB)/天然橡胶(NR)复合材料,通过扫描电镜、拉伸试验机和应变扫描仪分别对所制备复合材料的界面形貌、力学性能和Payne效应进行了测试分析,考察了混炼方式对复合材料宏观力学性能及Payne效应的影响。结果表明,与纯CB填料相比,在干湿两种混炼方式下,添加适量的HCNFs(1～6份)能提高HCNFs/CB/NR复合材料的300%定伸应力、扯断伸长率、拉伸强度和硬度。与干法混炼相比,湿法混炼能明显增强HCNFs/CB/NR复合材料的Payne效应,并提升在HCNFs高添加量(2～6份)条件下的拉伸强度和扯断伸长率,这主要源于湿法混炼能够有效改善HCNFs在橡胶基质中的分散性。     

水体中微塑料的环境影响行为研究进展

微塑料是指一类广泛存在于环境中的粒径小于5mm的塑料颗粒的总称，当其存在于水体环境中，容易吸附其他污染物，影响它们的迁移行为，进而对生态效应产生影响。本文依据水体环境中微塑料的相关研究报道，对微塑料在水环境中的影响行为进行概述。主要从微塑料的物理、化学和生物特性在环境中的变化特性，微塑料与环境中其他污染物质的相互作用关系，以及微塑料及其复合污染体系对水生生物造成的生态效应影响等3个方面对微塑料的环境行为进行总结、归纳与阐述。最后，针对微塑料对水环境中的环境影响效应，提出了今后的研究方向与展望。     

以资源整合重组助推南山矿下属集体企业转型发展的新探索

为解决南山矿下属集体企业面临的人员老化严重、生产装备落后、职工就业压力大等发展难题，探索了以资产整合、业务整合、人员整合和管理整合四位一体的资源整合重组新模式，扭转了企业经营困局，维护了矿区和谐稳定，促进了企业转型发展，对同类矿山具有良好的借鉴作用。      

Excitonic Properties of Chemically Synthesized 2D Organic–Inorganic Hybrid Perovskite Nanosheets

2D organic–inorganic hybrid perovskites (OIHPs) represent a unique class of materials with a natural quantum‐well structure and quasi‐2D electronic properties. Here, a versatile direct solution‐based synthesis of mono‐ and few‐layer OIHP nanosheets and a systematic study of their electronic structure as a function of the number of monolayers by photoluminescence and absorption spectroscopy are reported. The monolayers of various OIHPs are found to exhibit high electronic quality as evidenced by high quantum yield and negligible Stokes shift. It is shown that the ground exciton peak blueshifts by ≈40 meV when the layer thickness reduces from bulk to monolayer. It is also shown that the exciton binding energy remains effectively unchanged for (C₆H₅(CH₂)₂NH₃)₂PbI₄ with the number of layers. Similar trends are observed for (C₄H₉NH₃)₂PbI₄ in contrast to the previous report. Further, the photoluminescence lifetime is found to decrease with the number of monolayers, indicating the dominant role of surface trap states in nonradiative recombination of the electron–hole pairs.     

Enhanced hydrogen storage performance of three-dimensional hierarchical porous graphene with nickel nanoparticles

Three-dimensional hierarchical porous graphene with nickel nanoparticles (3DHPG-Ni) was synthesized through electrostatic assembly method with the assistance of poly (methyl methacrylate) (PMMA) template and subsequent removal of PMMA template by calcination. The morphology, microstructure and hydrogen adsorption properties of 3DHPG-Ni nanocomposites were examined in detail. The obtained 3DHPG-Ni nanocomposite exhibited hierarchical porous structure composed of macro-, meso- and micropores, high specific surface area (925 m² g^?1), large pore volume (0.58 cm³ g^?1) and excellent hydrogen storage capacity. Under the pressure of 5 bar, 3DHPG-Ni nanocomposite showed a maximum hydrogen capacity of 4.22 wt% and 1.95 wt% at 77 K and 298 K, respectively, demonstrating that the as-prepared 3DHPG-Ni nanocomposite was supposed to be a promising material with outstanding properties for practical applications in the field of hydrogen storage. The three-dimensional hierarchical porous structure, evenly distributed Ni nanoparticles and hydrogen spillover effect were responsible for the enhanced hydrogen storage capacities.     

融合环境因素的有限空间毒气扩散危害程度分析

为探究环境因素对毒气扩散危害程度的影响,通过对比有限空间内外环境差异,了解气体在有限空间内受力情况,并以传统高斯烟羽模型为基础,考虑扩散气体与有限空间边界碰撞产生的反射作用,建立了适用于有限空间气体扩散的改进高斯烟羽模型。深度剖析有限空间气体扩散环境,挖掘气体扩散主要关联因子,构建风速、地表粗糙度对有限空间气体扩散的影响函数;参照有限空间环境特征,分别设置3种不同风速与2种不同地表粗糙度,推求6种不同环境条件下气体扩散面积,阐明风速与地表粗糙度对有限空间气体扩散的影响程度。结果表明:在单一风速条件下,风速越高,地表粗糙度越低,洞室内H2S气体滞留时间越短,洞室内气体的扩散面积越小;风速越低,地表粗糙度越高,洞室内气体的扩散面积越大。     

微裂隙中水泥浆液渗滤效应的可视化试验研究

在微裂隙岩体注浆过程中,水泥浆液的渗滤效应对注浆效果的影响显著。自主研制了一套微裂隙注浆可视化试验系统,该系统由注浆系统、微裂隙模型以及监测系统3个部分组成,监测系统又分为显微监测系统和压力流量监测系统。当水泥浆液进入微裂隙模型后,利用显微监测系统对裂隙入口处的渗滤效应进行实时观测。利用压力流量监测系统对注浆试验过程中的注浆压力以及累计流量进行自动记录。运用自主设计的微裂隙注浆可视化试验系统,对微裂隙中的水泥浆液渗滤过程进行试验研究。采用3种水泥浆材(超细水泥Ⅰ、超细水泥Ⅱ和普通水泥),研究在注浆压力2.0 MPa、水灰比1.0的条件下,不同水泥颗粒粒径大小在不同裂隙开度下的浆液渗滤效应。通过试验发现,当裂隙开度较小时,在裂隙入口处形成了完整的半圆拱形滤饼;随着裂隙开度的增加,在裂隙入口处形成断续分布状滤饼;当裂隙开度增加到无渗滤发生时,裂隙入口处仅残留少量水泥颗粒附着物。通过试验获得了3种水泥的最小可注入裂隙开度大小b min和最小无渗滤裂隙开度大小b crit:超细水泥Ⅰ的b min和b crit分别为80和280μm;超细水泥Ⅱ的b min和b crit分别为100和300μm;普通水泥的b min和b crit分别为140和310μm。研究结果发现水泥粒径的减小对最小可注入裂隙开度大小的影响较大,但对最小无渗滤裂隙开度大小的影响较小。结合渗滤趋势k值,发现随着水泥粒径的减小,相应的k min和k crit值会随之增加,水泥浆液更容易在裂隙入口处发生渗滤,这是因为超细水泥比表面积更大,水泥颗粒间易发生团聚。     

Effect of Mo on corrosion behavior of Ni20Cr–xMo alloys in air with NaCl–KCl–CaCl2 vapor at 570°C

The effect of Mo on the corrosion behavior of Ni20Cr–xMo alloys in an oxidizing chlorine-containing atmosphere using air mixed with the salt-vapor mixture of NaCl–KCl–CaCl₂ at 570°C was investigated. The results revealed that the corrosion performance of the Ni20Cr alloys in the oxidizing chlorine atmosphere was improved by Mo addition of up to 3 wt%. The Mo-free alloy formed a potassium chromate during corrosion as a result of the reaction between the Cr₂O₃ scale and KCl vapor. The chromate formation increased the chlorine potential at the scale surface and induced the breakdown of the protective Cr₂O₃ scale, resulting in internal chromium chloride precipitates and a Cr-depleted zone. In contrast, the presence of Mo resulted in the formation of a NiO scale, which did not react with the salt vapors and, therefore, prevented the formation of chromates. The beneficial effect of Mo on the high-temperature chlorination of Ni–Cr alloys in salt-vapor-containing atmospheres was ascribed to the suppression of chlorine generation due to NiO scale formation.