我国石墨资源、市场与技术现状及发展趋势

为促进我国石墨资源开发利用产业的健康发展，在介绍了我国石墨资源的分布与市场供需情况的基础上，分析了当前石墨矿选矿技术的特点，矿物加工过程中存在的问题，指出了石墨选矿技术的发展趋势及方向。     

Joining of dense Si3N4 ceramics with tape cast Lu-Al-Si-O-N interlayer

Lu-Al-Si-O-N tapes with different thickness were used to join gas pressure sintered Si₃N₄ ceramics. The microstructure of the joints and the influences of the joint thickness and joining temperature on the bonding strength of the as-joined Si₃N₄ ceramics have been investigated. The highest bonding strength about ~ 300 MPa of the joined specimens was achieved by using 450 µm interlayer at 1450 °C. The existence of Si₃N₄ nanowires was beneficial for the improvement of the bonding strength by interweaving the oxynitride glass matrix in the joint region.     

Study on depositing SiO2 nanoparticles on the surface of jute fiber via hydrothermal method and its reinforced polypropylene composites

To improve the interfacial compatibility of jute fiber reinforced polypropylene (PP) composites, hydrothermal method was used to deposit SiO₂ nanoparticles on the surface of pretreated jute fibers and the effect of reaction factors (tetraethoxysilane [TEOS] concentration, ammonia concentration, and reaction temperature) on the deposition of SiO₂ nanoparticles were evaluated. The results of FTIR, XRD, SEM, and TEM showed that the amorphous SiO₂ nanoparticles with an average particle size of 65.0 nm were successfully deposited on the surface of jute fibers at the TEOS/H₂O volume ratio of 1:2, ammonia of 0.55 M, reaction temperature of 100 °C (0.15 MPa) for 5 h. Compared with the sol–gel method, SiO₂ nanoparticles obtained by the hydrothermal method possessed smaller particle size and were less agglomerated, which can better fill in the surface defects of the jute fibers and result in a 12.9% increase in the tensile strength. The study on the mechanical properties and interface performance of the jute fiber reinforced PP composites indicated that the interfacial compatibility between jute fibers and PP was obviously improved. The tensile and impact strength of the composites reinforced with nano‐SiO₂ deposited jute fibers were increased by 26.87% and 25.65%, respectively, compared with the untreated jute fibers. J. VINYL ADDIT. TECHNOL., 26:43–54, 2020. © 2019 Society of Plastics Engineers     

H13钢等离子堆焊Ni60A/Cr3C2覆层的磨损及热疲劳性能

采用等离子堆焊技术在H13钢基体表面上制备了Ni60A/Cr₃C₂堆焊覆层,研究了覆层的磨损行为和热疲劳性能。在600 ℃下销盘试验的结果表明,镍基碳化铬复合覆层的耐磨性是Ni60A堆焊覆层的2.8倍和基材H13钢的11.6倍。镍基覆层可以显著降低H13钢的摩擦因数,加入碳化铬则会削弱覆层的摩擦性能。随着磨损的进行,主要磨损机理从氧化磨损演变为磨粒磨损和粘着磨损。在800 ℃到室温下的热疲劳测试结果表明,镍基碳化铬复合覆层在48个热循环后疲劳裂纹达到200 μm,早于镍基覆层的62次。这说明高温氧化促进热疲劳裂纹的产生。碳化铬增强相从镍基上剥离,导致镍基复合覆层热疲劳性能下降。     

630℃超超临界二次再热塔式锅炉热力特性与壁温耦合计算研究

630℃超超临界火电技术作为下一代超超临界发电技术,对于煤炭资源的节约、发电机组的经济性以及环境改善,都显示了优越性。目前630℃超超临界锅炉的热力计算还缺乏相关研究。本文以某1000MW超超临界二次再热塔式锅炉布置方案为例,将锅炉管道、炉膛、高温受热面作为串联管路计算,在工质侧将热力计算与管路计算进行耦合建立数值分析模型。该计算模型能够同时得到比实现水动力和热力计算更精细的结果,对后续700℃工程持续优化提升做好技术储备。     

MSCT多期增强扫描在肾脏透明细胞癌中的诊断价值

目的探讨多排螺旋CT(MSCT)多期增强扫描在肾脏透明细胞癌诊断中的规律性,提高对该肿瘤诊断水平。方法回顾性分析2016年1月~2018年6月14例均经手术切除病理证实为肾脏透明细胞癌患者的CT影像资料,所有病例均行MSCT平扫及多期动态增强扫描。结果14例肾脏透明细胞癌形态大多数呈圆形或者类圆形,瘤体最大径范围1.7cm^11.3cm,平均(4.8±1.4)cm,13例CT平扫时肿瘤密度不均匀,呈等低密度,1例呈等密度;12例出现坏死囊变,钙化1例,伴肾盂、肾盏侵犯2例;动态增强扫描可见12例包膜完整,1例均匀性强化,13例不均匀性强化;引入对比剂后皮质期,出现10例病灶强化幅度大于肾皮质,而仅4例低于肾皮质,三期平均CT值分别为110±30Hu,90±15Hu及75±14Hu,其中在实质期出现13例肿瘤强化幅度小于肾实质,仅1例大于肾实质。结论引入对比剂动态增强扫描后,肾脏透明细胞癌在皮质期明显不均匀强化,实质期强化幅度下降显著,呈现出典型的“快进快出”血流动力学强化方式,且肿瘤容易出现坏死、囊变为其特点。     

某贫磁赤铁矿石选矿工艺试验研究

为了使某矿山贫磁赤铁矿资源得到合理的开发利用，针对现开采部位矿石的性质和可选性问题，进行了工艺矿物学和可选性试验研究。试验结果表明：采用弱磁、强磁—阴离子反浮选工艺可得到精矿铁品位68.55%、精矿产率36.41%、金属回收率79.92%、尾矿品位9.86%的较好选别指标，说明矿石的可选性较好，为该矿石的合理开发利用提供了可靠的技术依据。     

楼宇型分布式能源系统设备容量和运行策略优化研究

设备容量优化和运行策略优化是分布式能源系统设计，运行的关键问题。为实现分布式能源系统的经济效益，能效水平和环境效益最大化，针对楼宇型分布式能源系统建立了相对普适化的物理模型和数学模型，以粒子群优化算法和线性规划相结合，采用两阶段优化方法计算系统的最优容量配置，并给出运行策略。以某写字楼的分布式能源系统为例，得到最优的系统设备容量和全年逐时运行策略，并采用遍历法验证计算结果的准确性。优化的分布式能源系统与传统供能系统相比，费用年值降低7.79%，年总能耗降低24.18%，污染物排放量减少了62.77 %。     

Flexible Porous Organic Polymer Membranes for Protonic Field-Effect Transistors

Artificial transistors represent an ideal means for meeting the requirements in interfacing with biological systems. It is pivotal to develop new proton-conductive materials for the transduction between biochemical events and electronic signals. Herein, the first demonstration of a porous organic polymer membrane (POPM) as a proton-conductive material for protonic field-effect transistors is presented. The POPM is readily prepared through a thiourea-formation condensation reaction. Under hydrated conditions and at room temperature, the POPM delivers a proton mobility of 5.7 × 10⁻³ cm² V⁻¹ s⁻¹; the charge carrier densities are successfully modulated from 4.3 × 10¹⁷ to 14.1 × 10¹⁷ cm⁻³ by the gate voltage. This study provides a type of promising modular proton-conductive materials for bioelectronics application.