OBE理念推动化工设备机械基础课程的改革实践*

以应用型人才培养为目标,探索了利用OBE理念推动化工设备机械基础课程及其课程设计的改革实践。以OBE理念为指导,结合CDIO和LBL的教学模式,提出在教学内容、平台在线课程建设、第二课堂教学、课程设计和考核方法等方面的改革方案,增强了课程的应用性和成果产出,不仅提高了学生对理论知识掌握的牢固度,更提高了学生的实践能力、对知识的灵活应用能力和创新能力,与实际应用连接更加紧密,有效地实现了高素质的应用型人才输出。     

不同的烧结工艺对Sm-Co2∶17型高温磁体性能的影响

采用中频感应熔炼法制备了Sm( Co0.79 Fe0.09 Cuo.085 Zr0.032) 7.95合金,采用传统烧结工艺,在1200 ～1240℃烧结1h,1165 ～1190℃固溶处理3h,快速风冷淬火后在840 ℃保温12h,以0.4 ·min-1的冷速冷却至420℃,保温10h,最后随炉冷却.磁体经过加工后,采用不同的磁性测试手段对磁体进行测试.结果表明,磁体的剩磁随烧结温度的升高而增大,矫顽力最好的工艺为1230℃烧结1h,然后在1180℃固溶3h.将此工艺制备的磁体采用中国计量科学院NIM-500C超高温永磁测量仪测试,磁体在773 K时的最大磁能积为10.94 MGOe,高于已经报道的同Z值的2∶17型永磁体.磁体的磁滞回线通过振动样品磁强计( VSM)测得,室温下Br=10.5 kGs,Hcj=30.21 kOe,(BH)max=25.60MGOe; 773 K时磁体Br=7.45 kGs,Hcj=6.02 kOe,(BH) max=9.85 MGOe.剩磁温度系数α=-0.0624％·℃-1,矫顽力温度系数β=-0.169％·℃-1.     

An Efficient Method for The Synthesis of 4‐Arylfuro[2,3‐a][4,7]phenanthroline Derivatives Catalyzed by Iodine

A mild and an efficient method for the synthesis of 4‐arylfuro[2,3‐a][4,7]phenanthroline derivatives via three‐component reaction of aromatic aldehyde, quinolin‐6‐amine and 2,3‐dihydrofuran is described using iodine as catalyst. The features of this procedure are mild reaction conditions, good yields and operational simplicity.     

Knockout reaction mechanism studied by 6He projectile

Knockout reaction experiment was carried out by using the ⁶He beams at 61.2 MeV/u impinging on a CH₂ target. The α core fragments at forward angles were detected in coincidence with the recoiled protons at larger angles. From this exclusive measurement the valence nucleon knockout mechanism and the core knockout mechanism can be distinguished by the relation between the polar angles of the core fragments and the recoiled protons, respectively. It is demonstrated that the core knockout mechanism may result in some strong contamination to the real invariant mass spectrum.

     

Palladium‐Catalyzed Direct Cyclopropylation of Heterocycles

Many 1,3‐azoles and thiophenes are directly cyclopropylated in the presence of a simple palladium catalyst. The relative configuration on the three‐membered rings is retained in the products. Thus, the cyclopropyl–halide bond undergoes concerted oxidative addition to palladium(0) and cyclopropyl radicals are not involved in the productive pathway.     

Palladium-catalyzed synthesis of diarylbenzenes from coupling reactions between equal amount of diiodoarenes and arylboronic acids

We reported a highly effective Pd-catalytic system for the synthesis of diarylbenzenes through Suzuki-type reaction between equal amount of diiodoarenes and arylboronic acids. This preferential oxidative addition resulted in such high selectivity.     

Ultrathin Co3S4 Nanosheets that Synergistically Engineer Spin States and Exposed Polyhedra that Promote Water Oxidation under Neutral Conditions

Development of efficient and affordable electrocatalysts in neutral solutions is paramount importance for the renewable energy. Herein, we report that the oxygen evolution reaction (OER) performance of Co₃S₄ under neutral conditions can be enhanced by exposed octahedral planes and self‐adapted spin states in atomically thin nanosheets. A HAADF image clearly confirmed that the active octahedra with Jahn–Teller distortions were exposed exclusively. Most importantly, in the atomically thin nanosheets, the spin states of Co³⁺ in the octahedral self‐adapt from low‐spin to high‐spin states. As a result, the synergistic effect endow the Co₃S₄ nanosheets with superior OER performance, with exceptional low onset overpotentials of circa 0.31 V in neutral solutions, which is state‐of‐the‐art among inorganic non‐noble metal compounds.     

Adsorption of SO2 and chlorobenzene on activated carbon

Activated carbon is very effective for simultaneous removal of multiple pollutants. The adsorption of SO₂ and chlorobenzene modeling of VOCs on activated carbon was investigated in a fixed-bed reactor by four kinds of activated carbon. The results show that the SO₂ adsorption is affected by the BET surface and basic functional groups as C=O and π–π* groups of the carbon, while the chlorobenzene adsorption is strongly affected by the carbon pore structure, with the micropore volume deciding the adsorption amount and larger pores increasing the adsorption rate. The chlorobenzene adsorption is little affected by the chemical properties of activated carbon as the O/C ratio detected by XPS. The effect of SO₂ on the chlorobenzene adsorption was investigated, with the results showing the SO₂ seriously restricts the individual chlorobenzene adsorption and this effect becomes smaller in the presence of O₂. The adsorption products were analyzed by TPD-MS and the initial decomposition temperatures are 380 K for chlorobenzene and 500 K for SO₂, showing that SO₂ is much more stable adsorbed than chlorobenzene. The changes of the carbon functional groups that the CO₂ desorption peak emerges at 700 K and decreases at 1000 K with the chlorobenzene adsorption, were observed by TPD-MS, indicating that the lactone and quinone groups on the carbon are likely to combine with the chlorobenzene and form weakly chemisorbed chlorobenzene.     

Three‐dimensional simulation of planar contraction viscoelastic flow by penalty finite element method

The planar contraction flow is a benchmark problem for the numerical investigation of viscoelastic flow. The mathematical model of three‐dimensional viscoelastic fluids flow is established and the numerical simulation of its planar contraction flow is conducted by using the penalty finite element method with a differential Phan‐Thien–Tanner constitutive model. The discrete elastic viscous split stress formulation in cooperating with the inconsistent streamline upwind scheme is employed to improve the computation stability. The distributions of velocity and stress obtained by simulation are compared with that of Quinzani's experimental results detected by laser–doppler velocimetry and flow‐induced birefringence technologies. It shows that the numerical results agree well with the experimental results. The numerical methods proposed in the study can be well used to predict complex flow patterns of viscoelastic fluids. Copyright © 2009 John Wiley & Sons, Ltd.