污泥生物炭中氮硫行为及环境效应研究进展

污泥生物炭中氮硫元素含量高，其氮硫行为和环境效应对全球气候变化的影响不容忽视。以往的研究中，研究者往往以富碳生物炭作为主要研究对象，关注碳对全球气候变化的行为和功效，而对氮硫元素的作用关注不够。本文从原始污泥基本性质到其热解过程，再到生物炭的老化，逐步对污泥生物炭整个生命周期内氮硫的行为及其环境效应研究进行综述，并对未来应注重开展的研究方向进行展望，为生物炭中氮硫元素固定、释放及与之关联的环境效应和温室气体排放控制研究提供理论基础。分析表明，污泥中氮元素含量普遍高于硫元素，且热解过程中氮比硫更容易转移至气相产物。氮硫元素随热解温度的增加，在三相产物中的分配都是炭中持续减少，油中先增后减，气中一直增加。高温（＞800℃）条件下，气相中的氮含量高于固相，而硫元素则仍然主要存在于固相中。污泥生物炭老化及其环境效应研究表明，污泥生物炭氮硫元素与土壤的相互作用及其温室效应问题在今后的研究中应引起重视。     

王村煤业MG400/930-WD(3.3)型电牵引采煤机截割部扭矩轴优化设计研究

针对王村煤业MG400/930-WD(3.3)型电牵引采煤机截割部扭矩轴在截割电机负载超载情况发生断裂不能实现对截割电机保护的问题,本文提出了一种截割部扭矩轴设计优化方案。方案主要进行了扭矩轴材料选择、表面处理工艺改进以及卸荷槽的再设计,并对卸荷槽进行了参数试验,优化后的扭矩轴可以在电机超载时及时断裂,有效保护截割电机。     

黔西南某中高硫煤脱硫过程中微量元素的分配特性研究

为探究黔西南某中高硫煤中微量元素的富集程度,以及在脱硫降灰提质利用过程中微量元素的分配特性,通过摇床对其脱硫降灰进行了试验研究,并在合适的分选工艺条件下,考察了原煤、精煤和尾煤产品中微量元素的分配特征。通过“一粗一精一扫”重选,可获得产率32.83%、硫分0.96%、灰分11.16%的合格精煤产品。分选产品微量元素分析结果表明,该分选工艺对Cu、Sb、As、Co、Mo、TI、Ni等有害元素具有较好的脱除效果,并能一定程度富集锂和稀土等有价微量元素。通过此工艺可分别回收28.73%和47.37%的锂至精煤和中煤产品,精煤煤灰中Li₂O理论含量达5 258 μg/g,具有综合回收利用价值。研究结果可为该类中高硫煤炭资源的清洁与综合利用提供参考。     

一类两性分枝过程条件均值增长率的极限性质

本文主要研究随机环境中配对依赖人口数两性 Galton-Watson 分枝过程的条件均值增长率的极限性质．利用上可加函数的性质，得到配对单元平均增长率的极限性质和该过程条件均值的上界和下界．文中给出了关于过程条件均值增长率的两个序列，利用配对单元平均增长率的性质，获得了这两个序列的极限性质．随机环境中配对依赖人口数两性分枝过程比较复杂，本文的结论推广了现有的研究成果．     

Atomic Modulation Triggering Improved Performance of MoO3 Nanobelts for Fiber‐Shaped Supercapacitors

Asymmetric supercapacitors (ASCs) are emerging as a new class of energy storage devices that could potentially meet the increasing power and energy demand for next‐generation portable and flexible electronics. Yet, the energy density of ASC is severely limited by the low capacitance of the anode side, which commonly uses the carbon‐based nanomaterials. Here, the demonstration of sulfur‐doped MoO_3?x nanobelts (denoted as S‐MoO_3?x) as the anode for high‐performance fiber‐shaped ASC are reported. The Mo sites in MoO₃ are intentionally modulated at the atomic level through sulfur doping, where sulfur could be introduced into the MoO₆ octahedron to intrinsically tune the covalency character of bonds around Mo sites and thus boost the charge storage kinetics of S‐MoO_3?x. Moreover, the oxygen defects are occurring along with sulfur‐doping in MoO₃, enabling efficient electron transport. As expected, the fiber‐shaped S‐MoO_3?x achieves outstanding capacitance with good rate capability and long cycling life. More impressively, the fiber‐shaped ASC based on S‐MoO_3?x anode delivers extremely high volumetric capacitance of 6.19 F cm^?3 at 0.5 mA cm^?1, which makes it promising as one of the most attractive candidates of anode materials for high‐performance fiber‐shaped ASCs.     

A Combined Ordered Macro‐Mesoporous Architecture Design and Surface Engineering Strategy for High‐Performance Sulfur Immobilizer in Lithium–Sulfur Batteries

The practical application of lithium–sulfur (Li–S) batteries is hindered by the “shuttle” of lithium polysulfides (LiPS) and sluggish Li–S kinetics issues. Herein, a synergistic strategy combining mesoporous architecture design and defect engineering is proposed to synthesize multifunctional defective 3D ordered mesoporous cobalt sulfide (3DOM N‐Co₉S_8?x) to address the shuttling and sluggish reaction kinetics of polysulfide in Li–S batteries. The unique 3DOM design provides abundant voids for sulfur storage and enlarged active interfaces that reduce electron/ion diffusion pathways. Meanwhile, X‐ray absorption spectroscopy shows that the surface defect engineering tunes the CoS₄ tetrahedra to CoS₆ octahedra on Co₉S₈, endowing abundance of S vacancies on the Co₉S₈ octahedral sites. The ever‐increasing S vacancies over the course of electrochemical process further promotes the chemical trapping of LiPS and its conversion kinetics, rendering fast and durable Li–S chemistry. Benefiting from these features, the as‐developed 3DOM N‐Co₉S_8?x/S cathode delivers high areal capacity, superb rate capability, and excellent cyclic stability with ultralow capacity fading rate under raised sulfur loading and low electrolyte content. This design strategy promotes the development of practically viable Li–S batteries and sheds lights on the material engineering in related energy storage application.     

基于AMESim的液压马达加载系统研究

液压马达作为液压系统的执行元件在工程机械上广泛应用,针对液压马达加载工况下的输出特性,利用Simulink和AMESim软件对系统进行联合仿真建模,并对系统的运行状态、控制性能、回收性能进行研究,对液压马达加载系统的设计和改进具有重要的参考意义。     

Selective Analysis of Sulfur-Containing Species in a Heavy Crude Oil by Deuterium Labeling Reactions and Ultrahigh Resolution Mass Spectrometry

A heavy crude oil has been treated with deuterated alkylating reagents (CD₃I and C₂D₅I) and directly analyzed without any prior fractionation and chromatographic separation by high-field Orbitrap Fourier Transform Mass Spectrometry (FTMS) and Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (FT-ICR MS) using electrospray ionization (ESI). The reaction of a polycyclic aromatic sulfur heterocycles (PASHs) dibenzothiophene (DBT), in the presence of silver tetrafluoroborate (AgBF₄) with ethyl iodide (C₂H₅I) in anhydrous dichloroethane (DCE) was optimized as a sample reaction to study heavy crude oil mixtures, and the reaction yield was monitored and determined by proton nuclear magnetic resonance spectroscopy (¹H-NMR). The obtained conditions were then applied to a mixture of standard aromatic CH-, N-, O- and S-containing compounds and then a heavy crude oil, and only sulfur-containing compounds were selectively alkylated. The deuterium labeled alkylating reagents, iodomethane-d₃ (CD₃I) and iodoethane-d₅ (C₂D₅I), were employed to the alkylation of heavy crude oil to selectively differentiate the tagged sulfur species from the original crude oil.