Liquid phase hydrogenation of furfural to biofuel over robust NiCu/Laponite catalyst: A study on the role of copper loading

Sustainable production of biofuel and chemical feedstock through catalytic hydrogenation has now received increased attention due to the expeditious depletion of crude oil. In the present investigation, we developed a cost-effective and base metal-based NiCu/Laponite catalyst for liquid-phase hydrogenation of furfural into fuel range components. The robust catalysts were prepared by a simple co-impregnation method with constant loading of 5 wt% NiO with different wt.% of CuO (x) loadings (where x = 8, 10, 12 & 14%) on the Laponite support. The textural properties, surface acidity, and reduction of the synthesized catalysts were studied by employing various physicochemical characterizations such as XRD, N₂ sorption analysis, NH₃-TPD, H₂-TPR, and TGA. The obtained results revealed that optimum loading of 12% CuO and 5% NiO catalyst aids fine dispersion of copper and nickel oxide on the surface of the support. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images displayed the delamination of Laponite particles and dispersion of Ni-Cu catalyst on the support surface. The hydrogenation efficiency of the synthesized catalysts was tested in a bench top stainless steel autoclave reactor by liquid phase reaction condition of furfural at 150–210 °C under 10–25 bar H₂ pressure for 1–6 h. The excellent activity of 5Ni-12Cu/Laponite catalysts was compared and correlated with the physicochemical characteristics of the catalyst.     

不同组分比的HMX/DMI共晶炸药结构与性质的理论研究

利用分子动力学,研究了分子摩尔比对HMX/DMI共晶炸药几个重要晶面成键能的影响,对于不同分子的摩尔比的力学性质也进行了估算,借助M06-2x/6-311+G(2df,2p)方法对HMX/DMI复合物的溶剂效应也进行了研究。计算结果表明,(020)和(100)取代基模型具有最高的成键能和稳定性,1∶1和2∶1的化合物最稳定且具有最高的力学性能。分子间相互作用能和N–NO_2键离解能的变化对HMX/DMI共晶炸药的稳定性有较大影响。制备稳定的HMX/DMI共晶炸药应选用较低介电常数作溶剂。     

新型铁心柱绑扎结构在浇注型干式变压器中的应用

介绍了浇注干式变压器选用的一种新型铁心柱绑扎材料及耐热性能,对不同绑扎材料成本进行了对比.     

智能控制包装机的凸轮定位差动器的伺服系统

根据裹包机的伺服系统控制精度较差的问题,提出了分层结构的智能控制器,在低层使用两个精确控制的线性控制器,在顶层采用模糊揄的智能控制,经过仿真结果表明,该控制器的性能更为优越。     

Density functional studies of the electronic structure and adsorption at molybdenum oxide surfaces

The electronic structure and bonding at different oxygen sites of MoO₃(0 1 0) and (1 0 0) surfaces is reviewed on the basis of ab initio density functional theory (DFT-LCGTO) cluster calculations. The clusters are chosen as finite sections of the ideal MoO₃ surface where cluster embedding is achieved by bond saturation with hydrogen terminator atoms yielding clusters up to Mo₇O₃₀H₁₈. Resulting charge density distributions and binding properties are analyzed by populations, bond orders, and electrostatic potential maps. Interatomic binding at the surface is determined by both ionic and covalent contributions with a clear distinction between terminal oxygens and different bridging surface oxygens. Electronic differences between the MoO₃ (0 1 0) and (1 0 0) surfaces are found to be mainly due to the different atom arrangement while local atom charging and binding properties seem surface independent. The electronic surface parameters influence the behavior and reactions of adsorbed molecules as will be shown for H, OH, and C₃H₅ adsorbates.     

Structural,electronic and spectral properties referring to hydrogen storage capacity in binary alloy ScBn (n = 1–12) clusters

Based on the DFT calculations within GGA approximation, we have systematically studied the ScB_n (n = 1–12) clusters and their hydrogen storage properties. The results show that the maximal adsorption for H₂ molecules is ScB₇ 6H₂ structure with the hydrogen storage mass fraction about 9.11%. For ScB_n·mH₂ clusters as n = 7 or 9–12, the average binding energies between 0.202 and 0.924 eV are suggestively conducive to hydrogen storage. In these medium clusters, the moderate adsorption strength can benefit application of hydrogen energy owning to easily adsorption and dissociation on H₂ molecules at room temperature and 1 bar pressure. Furthermore, the absorption spectrum is also investigated from TDDFT calculation. An obvious red-shift of spectral lines at 4.2 eV or 5.6 eV is detected with the increase of number of H₂ molecules. It can be regard as ‘fingerprint’ spectrum in experiment to indicate adsorption capacity of H₂ molecules for ScB_n·mH₂ nanostructures.     

不同结合体系刚玉基浇注料的脱水行为

分别将水合结合、水合+凝聚结合、凝聚+水合结合和凝聚结合的刚玉基浇注料成型和室温下养护后称量,再依次称量110℃干燥后以及从200℃开始每间隔100℃至1000℃热处理后的质量,以质量损失和变化快慢来反映浇注料在养护和加热过程中的脱水行为。借助XRD、TG和DTA对各浇注料基质浆体的脱水行为和相组成进行分析。浇注料的脱水可分为剧烈、平缓和完成3个阶段。水合结合主导的水泥结合的浇注料和低水泥浇注料的脱水相似,3个脱水阶段分别为室温～300℃、300～600℃和600℃以上。以凝聚结合主导的二氧化硅微粉和水合氧化铝结合的浇注料、MgO-SiO2-H2O结合的浇注料及超低水泥浇注料的脱水行为相似,3个脱水阶段分别为室温～110℃烘干、110～400℃和400℃以上。     

Enhancement of hydrogen storage capacity on co-functionalized GaS monolayer under external electric field

Hydrogen storage properties of co-functionalized 2D GaS monolayer have been systematically investigated by first-principles calculations. The strength of the binding energy of hydrogen (H₂) molecules to the pristine GaS surface shows the physisorption interactions. Co-functionalized GaS sheet by Li, Na, K and Ca atoms enhanced the capacity of binding energies of hydrogen and strength of hydrogen storage considerably. Besides, DFT calculations show that there is no structural deformation during H₂ desorption from co-functionalized GaS surface. The binding energies of per H₂ molecules is found to be 0.077 eV for pristine GaS surface and 0.064 eV–0.37 eV with the co-functionalization of GaS surface. Additionally, in the presence of applied external electric field enhanced the strength of binding energies and it is found to be 0.09 eV/H₂ for pristine GaS case and 0.19 eV/H₂ to 0.38 eV/H₂ for co-functionalized GaS surface. Among the studied GaS monolayer is found to be the superior candidate for hydrogen storage purposes. The theoretical studies suggest that the electronic properties of the 2D GaS monolayer show the electrostatic behavior of hydrogen molecules which confirms by the interactions between adatoms and hydrogen molecules before and after hydrogen adsorption.     

类石墨固体润滑镀层在油泵类零部件上的应用

本文对类石墨固体润滑膜进行了一系列的研究,包括结合力,硬度,摩擦磨损性能等,研究了其在油泵等燃油喷射系统上应用的可行性。在柱塞类零件上进行了膜层的制备,并检测了镀层前后产品的尺寸精度变化。经研究,固体润滑膜耐磨性好,摩擦系数小,镀层均匀,适于燃油喷射系统的使用工况,且镀层均匀,产品在圆度、圆柱度、粗糙度等方面保持性良好,在燃油喷射系统等发动机部件上的应用将会越来越广泛。     

快速成形中PAN基碳纤维/HA力学性能模拟研究

在人工骨支架增材制造过程中,为了制造出具有不同力学性能的人造骨支架适合不同病患,提出利用分子动力学(Molecular dynamics,MD)模拟方法,研究所用基体复合材料(聚丙烯腈(Poly acrylonitrile,PAN)基碳纤维和羟基磷灰石(Hydroxyapatite, HA))表面之间的相互作用及力学性能。分别在原子模拟凝聚相优化分子势能力场(Condensed-phase optimized molecular potentials for atomistic simulation studies,COMPASS)和通用力场(Universal force field,UFF)下,对比计算HA和PAN基碳纤维/HA的力学性能,并比较其弹性模量和泊松比,证明羟基磷灰石是一种各向异性材料,并给出羟基磷灰石中添加PAN基碳纤维可以有效改善其力学性能。针对沿不同剪切方向上的PAN基碳纤维/羟基磷灰石进行动力学计算,表明在不同的力场下,羟基磷灰石均是在沿(110)剪切面上与聚丙烯腈纤维产生的结合能值较大。结合径向分布函数分析,揭示了PAN/HA复合材料主要是通过PAN中的N原子与HA表面发生强作用,从而提高PAN/HA基体力学性能。