“四体三化”学生综合评价体系改革在中职汽车运用与维修专业的实践研究

随着职业教育改革的深入,对学生综合素质的评价日益受到重视。在中职汽车运用与维修专业领域,实现学生综合素质的全面评价尤为关键。本研究旨在探讨“四体三化”综合评价体系在该专业中的应用,以促进学生多样化技能的培养和全面素质的提升。通过分析当前评价体系的实践情况和面临的挑战,本文提出了一系列创新实践和推广建议,为中职汽车运用与维修专业的教育改革提供理论和实践上的支持。

Preparation and characterization of ferromagnetic fluids for hyperthermia of tumor

Aim To prepare and characterize ferromagnetic fluids for hyperthermia of tumor. Methods Ferromagnetic fluids （FFs） of magnetite （Fe3O4） was prepared in the presence of polyethylene glycol （PEG-6000） by chemical precipitation method. The iron content of the FFs was determined by spectrophotometric method using o-phenanthroline. The FFs/PEG-6000 was characterized by transmission electron microscopy （TEM）, X-ray diffraction （XRD）, infrared spectrometry （IR）, and vibrating sample magnetometer （VSM）. Heating effects of the FFs was measured in an alternating magnetic field in vitro. The hyperthermia of FFs in a rabbit was performed. Results The FFs/PEG-6000 was proved to be composed of Fe3O4 by XRD and IR. TEM showed that the ferromagnetic particles appeared to be almost spherical and dispersed well The average particle size was 13.3 ± 3.8 nm by XRD. The saturation magnetization and residual magnetization of the FFs were 23.39 A/m （1.556 emu/g） and 0.56 A/m （0.02604 emu/g）, respectively. The coercive force was 12 Oe. The specific absorption rate （SAR） of FFs was 69 ± 10W/g [Fe]. After direct injection of FFs to hepatic VX2 carcinoma of a rabbit, the temperature in the core of the tumor was between 41 - 46 ℃ in an alternating magnetic field. Conclusion FFs/PEG-6000 was expected to be useful in hyperthermia of tumor.

Pt supported on octahedral Fe_3O_4 microcrystals as a catalyst for removal of formaldehyde under ambient conditions

Several catalysts comprising Pt supported on octahedral Fe3O4（Pt/Fe3O4） were prepared by a facile method involving co-precipitation followed by thermal treatment at different temperatures. A variety of characterization results revealed that this preparation process afforded highly crystalline octahedral Fe3O4 with a uniform distribution of Pt nanoparticles on its surface. The thermal-treatment temperature significantly influenced the redox properties of the Pt/Fe3O4 catalysts. All the Pt/Fe3O4 catalysts were found to be catalytically active and stable for the oxidation of low-concentration formaldehyde（HCHO） with oxygen. The catalyst prepared by thermal treatment at 80 °C（labelled Pt/Fe3O4-80） exhibited the highest catalytic activity, efficiently converting HCHO to CO2 and H2 O under ambient temperature and moisture conditions. The excellent performance of Pt/Fe3O4-80 was mainly attributed to beneficial interactions between the Pt and Fe species that result in the formation a higher density of active interface sites（e.g., Pt-O-FeO x and Pt-OH-FeO x）. The introduction of water vapor improves the catalytic activity of the Pt/Fe3O4 catalysts as it participates in a water-assisted dissociation process.

Some Limitations of BIOLOG System for Determining Soil Microbial Community

A laboratory experiment was conducted to evaluate the effect of triphenyltetrazolium chloride (TTC) on soil microorganisms and the availability of pH characterization medium in BIOLOG plates. Application of TTC decreased the color development sharply and resulted in a great biocidal effect on the growth and reproduction of soil microorganisms, indicating that TTC can affect the discrimination on soil microbial community. The microtitration plates with 21 carbon sources and two different pH levels (4.7 and 7.0) were used to determine microbial community structure of eight red soils. The average utilization (average well colour development) of the carbon sources in the plates with different pH levels generally followed the same sigmoidal pattern as that in the traditional BIOLOG plates, but the pH 4.7 plates increased the discrimination of this technique, compared with the pH 7.0 plates. Since most tested soils are acid, it seemed that it’s better to use a suitable pH characterization medium for a specific soil in the sole carbon source test.

Synthesis and Crystal Structure ofTrichlorotetrakis(tetrahydrofuran) Europium

Crystal of EuCl3(C4H8O4). was obtained from the reaction of C9H7Naand EuCl3,(0. 8: 1 mole ratio) in THF. It was crystallized in Fdd2 space group withunit cell parameters a=29. 161 (4), b=16. 558(6), c=9. 479 (3) A, V=4577 (4)A3, Z=8, Dc= 1.59 g/cm3, Mr=546. 75. F(000)=2192, A(Mo Ka) =0. 71069, u=31. 12 cm-1, T=293K. The final R and Rw values are 0. 040 and 0. 051 respective-ly. Three chlorine atoms and four oxygen atoms from THF are coordinated with cen-tral europium ion to form a pentagonal bipyramid polyhedron with coordination number7, the average Eu-Cl; bond length is 2. 637 A and Eu-O 2. 460A.

Preparation and characterization of ferromagnetic fluids modified by carboxyl PEG

To prepare and characterize the ferromagnetic fluid of Fe304 modified by carboxyl PEG （FF/carboxyl PEG） for hyperthermia of tumor, the magnetic nanoparticles （NPs） of Fe304 were prepared by chemical co-precipitation method, and then modified with carboxyl PEG. The iron content of FFs was determined by spectrophotometric method using o-phenanthroline. The stability of FF/carboxyl PEG was assessed by the sedimentation method. FF/carboxyl PEG was characterized by X-ray diffraction （XRD）, transmission electron microscopy （TEM）, infrared spectrometry （IR） and vibrating sample magnetometer （VSM）. Heating effect of FF/carboxyl PEG was measured in an alternating magnetic field in vitro. The stability of FF/carboxyl PEG was much better than that of unmodified ferromagnetic fluid. FF/carboxyl PEG was proved to be composed of Fe304 by both XRD and IR. TEM showed that the ferromagnetic particles were well-dispersed. The average particle size was calculated as 5 nm by XRD. The saturation magnetization and residual magnetization of FF/carboxyl PEG were 47.01 and 3.41 emu/g, respectively. The coercive force was 6.70e. The specific absorption rate （SAR） of the FF/carboxyl PEG was 63.0 W/g[Fe]. The FF/carboxyl PEG shows the promise for hyperthermia of tumor.

Low-field-induced spin-glass behavior and controllable anisotropy in nanoparticle assemblies at a liquid-air interface

Stacking nanoscale-building blocks into onedimensional(1D)assemblies with collective physical properties is a frontier in designing materials.However,the formation of 1D arrays using weak magnetic fields and an in-depth understanding of their magnetic properties remain challenging.Here,low-dimensional assemblies of iron oxide nanocubes with a disordered arrangement are fabricated at the diethylene-glycol/air interface in the presence of assembly fields(0/1/3/5/30/50 mT).Ring-shaped assemblies gradually transform as the assembly field increases from 0 to 50 mT,first to a porous network consisting of elongated assemblies and then to an aligned array of filaments,in which the aligned filaments are formed when the assembly field is≥3 mT and duration t>14 min.Spin-glass characteristics and static(dynamic)anisotropy factors~2(3)are achieved by tuning the strength of the assembly field.In the presence of a relatively weak assembly field,the interplay between dipolar interactions and disorder with respect to magnetic easy axis alignment leads to spin-glass characteristics.The alignment of the magnetic easy axes and the strength of the dipolar interactions increase with increasing assembly field,resulting in the disappearance of spin-glass characteristics and enhancement of the magnetic anisotropy.This study presents a strategy for obtaining magnetic assemblies with spin-glass behavior and controllable anisotropy while shedding light on the magnetic interactions of low-dimensional assemblies.