光纤感温火灾预警监测系统的设计与应用分析

阐述光纤感温预警监测系统的工作原理、系统设计及应用研究方面的概况及意义,探讨光纤感温火灾预警监测系统的设计与应用.     

腈纶表面接枝蛋白质改性纤维的结构与性能

腈纶经过表面水解、酰氯化和接枝反应等过程在表面接枝上大豆蛋白质,制成了蛋白质接枝改性腈纶。对其进行物理力学性能分析、红外分析和电子显微镜形貌观察表明:改性腈纶在表面接枝蛋白质的效果明显,其表面完全覆盖上了完整致密的蛋白质表面膜层;X射线衍射分析表明,蛋白质接枝改性腈纶的超分子结构与普通腈纶相比并没有发生大的变化,基本保持了原有腈纶的高序态和低序态共存的结构特征。     

Experimental study on the deformation and failure mechanism of overburden rock during coal mining using a comprehensive intelligent sensing method

Understanding the spatiotemporal evolution of overburden deformation during coal mining is still a challenge in engineering practice due to the limitation of monitoring techniques. Taking the Yangliu Coal Mine as an example, a similarity model test was designed and conducted to investigate the deformation and failure mechanism of overlying rocks in this study. Distributed fiber optic sensing(DFOS), highdensity electrical resistivity tomography(HD-ERT) and close-range photogrammetry(CRP) technolo...     

金属基底增敏的干涉型高温光纤传感器

为了实现对井下潜油电泵机组温度的实时监测,设计了一种由粗锥型单模--多模--单模(Coarse Cone Singlemode-Multimode-Singlemode, CCSMS)构成的马赫--曾德尔干涉(Mach-Zehnder Interferometer, MZI)型高温光纤传感器。该结构采用直接熔接的方法将单模光纤与多模光纤相熔接;接着通过调整熔接机的熔接参数,在单模光纤上制作出粗锥结构;最后将制备的结构嵌入铜基板的U型槽中,实现传感器的增敏封装。对封装后的传感器的温度响应特性进行了测试。实验结果表明,在40～250℃的温度范围内,该传感器实现了灵敏度为124.9 pm/℃的温度传感。对其稳定性和重复性进行了测试。结果表明,传感器的稳定性最大误差约为0.44%,重复性最大误差约为2.29 pm/℃。该传感器具有灵敏度高、重复性和稳定性好的特点,有望用于油气井下潜油电泵机组的温度监测。     

Association of Ligamentum Flavum Hypertrophy with Adolescent Idiopathic Scoliosis Progression—Comparative Microarray Gene Expression Analysis

The role of the ligamentum flavum (LF) in the pathogenesis of adolescent idiopathic scoliosis (AIS) is not well understood. Using magnetic resonance imaging (MRI), we investigated the degrees of LF hypertrophy in 18 patients without scoliosis and on the convex and concave sides of the apex of the curvature in 22 patients with AIS. Next, gene expression was compared among neutral vertebral LF and LF on the convex and concave sides of the apex of the curvature in patients with AIS. Histological and microarray analyses of the LF were compared among neutral vertebrae (control) and the LF on the apex of the curvatures. The mean area of LF in the without scoliosis, apical concave, and convex with scoliosis groups was 10.5, 13.5, and 20.3 mm², respectively. There were significant differences among the three groups (p < 0.05). Histological analysis showed that the ratio of fibers (Collagen/Elastic) was significantly increased on the convex side compared to the concave side (p < 0.05). Microarray analysis showed that ERC2 and MAFB showed significantly increased gene expression on the convex side compared with those of the concave side and the neutral vertebral LF cells. These genes were significantly associated with increased expression of collagen by LF cells (p < 0.05). LF hypertrophy was identified in scoliosis patients, and the convex side was significantly more hypertrophic than that of the concave side. ERC2 and MAFB genes were associated with LF hypertrophy in patients with AIS. These phenomena are likely to be associated with the progression of scoliosis.     

Pure Chitosan Biomedical Textile Fibers from Mixtures of Low- and High-Molecular Weight Bidisperse Polymer Solutions: Processing and Understanding of Microstructure–Mechanical Properties’ Relationship

Natural polymers, as extracted from biomass, may exhibit large macromolecular polydispersity. We investigated the impact of low molar mass chitosan (LMW, DP_w~115) on the properties of chitosan fibers obtained by wet spinning of chitosan solutions with bimodal distributions of molar masses. The fiber crystallinity index (CrI) was assessed by synchrotron X-ray diffraction and the mechanical properties were obtained by uniaxial tensile tests. The LMW chitosan showed to slightly increase the crystallinity index in films which were initially processed from the bimodal molar mass chitosan solutions, as a result of increased molecular mobility and possible crystal nucleating effects. Nevertheless, the CrI remained almost constant or slightly decreased in stretched fibers at increasing content of LMW chitosan in the bidisperse chitosan collodion. The ultimate mechanical properties of fibers were altered by the addition of LMW chitosan as a result of a decrease of entanglement density and chain orientation in the solid state. An increase of crystallinity might not be expected from LMW chitosan with a still relatively high degree of polymerization (DPw ≥ 115). Instead, different nucleation agents—either smaller molecules or nanoparticles—should be used to improve the mechanical properties of chitosan fibers for textile applications.     

Y对轴承钢上激光熔覆FeCoCrNi涂层结构和冲蚀磨损的影响

以激光熔覆方法在轴承钢上制得FeCoCrNi-xY高熵合金涂层,并对其处于气体环境中的耐高温冲蚀性进行了测试。研究Y对涂层结构和冲蚀磨损的影响。研究结果表明：随着Y增大,蜂窝形组织开始减少直到全部消失,生成了许多尺寸较小的M颗粒,形成了粒径更小以及分布形态更均匀的Y化物组织。提高Y的加入量后,涂层发生了硬度先减小再增大势,测试得到的硬度值介于720-960 HV范围内。当逐渐提高冲蚀角后,FeCoCrNi-xY涂层发生了冲蚀磨损率持续增大。FeCoCrNixY涂层获得了高于轴承钢的硬度,呈现明显的脆性特点。对FeCoCrNi-0.3Y涂层冲蚀形成了深度更大的犁沟,达到了更高的冲蚀磨损率。当温度提高后,磨损率同样呈现增大现象,不过变化幅度较低。各攻角下的涂层磨损形式并未受到温度的明显影响。     

铁通公司FTTH发展与建设思考

本文从FTTH发展思路、应用场景、建设模式等方面进行阐述,并对铁通公司FTTH下一步发展提出4点建议。     

Thickening and Rheological Properties of Crystalline Polyester Used in Low Pressure Sheet Molding Compounds

Low pressure sheet molding compound (LPMC,1.0-3.0 MPa,95-103 ℃) is a new kind of thermosetting material with crystalline polyester as a physical thickenner.LPMC is different from conventional SMC using an earth oxide thickening agent (e.g.MgO) as chemical thickenner,it relies on the physical thickening of crystalline polyester.Crystalline polyester resin is the key material to mold LPMC parts.Currently there was no report about the thickening mechanism of crystalline polyester in LPMC.In this article,crystalline polyester resins,whose melting points were between 45 ℃ and 89 ℃,were synthesized by a two-step esterification.The melt points of crystalline polyesters are controlled by regulating the mol ratio of the two glycols and the two acids.And by means of varying the content of crystalline polyester resin,the thickening effect on resin paste is investigated.In addition,the thickening mechanism of crystalline polyester in LPMC was investigated by FTIR and DSC analysis.The effects of the diameters and viscosity of crystalline polyester on the rheological property and fiber distribution of LPMC sheets were studied,too.Results show that the thickening effect is excellent when the weight content of crystalline polyester resin is 3%.And there exists three kinds of functions acting in the process of thickening:swelling,hydrogen bonds and induction crystallization.During the preparing process of resin paste in LPMC,the temperature of resin paste must be kept at 90 ℃.In addition,crystalline polyester make LPMC have a perfect fluid property.When the viscosity of LPMC sheet is beyond 1 kPa s,the fiber orientation is not obvious.But when the viscosity of LPMC sheet is about 500 Pa s,the fiber shows a certain degree of orientation.Moreover the study of physical and chemical thickening mechanism of crystalline polyester and the rheological discipline of LPMC sheets in the hot mould will provide the researchers and enterprises with theory guidance.     

广东省化纤行业的现状及未来发展建议

通过对广东省化纤发展现状和有利因素进行分析,指出了主要存在问题,提出未来发展建议.