Effects of electric-field treatment on a Ni-base superalloy

The effects of electric-field treatment on the microstructure and deformation behavior of a nickel-base superalloy were summarized.The results show that the electric-field treatment increases the ductility of the superalloy but has no evident influence on its static strength at both room and elevated temperatures,while,the strength increases but elongation changes weekly with the increasing tensile strain rate.It is found that the direction of microcrack propagation can be changed by the presence of the annealing twins during the tensile deformation,and it causes the increasing of the plastic deformation energy and delay of the fracture,which is considered as the reason for the increasing the ductility.

Effects of electric field treatment on microstructures of GH4199 superalloy after long-term aging

The effects of electric field intensity and treatment temperature on the microstructures of GH4199 superalloy after long-term aging were investigated. The results show that the number and size of carbides and TCP(σphase andμphase) phase in the alloy increase with increasing electric field intensity at the same heat treatment temperature and holding time. While the number and size of carbides and TCP phase are weekly influenced by treatment temperature with lower electric field intensity of 2 kV/cm. When the treat temperature is up to 1 093 K, annealing twins appear in the alloy, and the number of twins increases with increasing holding time. Since the electric field can provide the enough energy for the movement of vacancies and atom, it is considered that the nucleus of the twins formed with formation stack faults due to the mismatch of local atom in crystal caused by the vacancies, and the twins will grow with the increase of holding time. Meanwhile, such promoting effects on atom movement of the electric field increase with the increase of the electric field intensity, meantime the carbides and TCP phase grow fast with the increase of electric field intensity.

EFFECT OF SOLUTION TREATMENT IN AN ELECTRIC FIELD ON MECHANICAL PROPERTIES AND MICROSTRUCTURE OF 2091 Al—Li ALLOY

Solution treatment of 20% Al-Li alloy in an electric field has been studied. The results show that it increases the solubility of elements and accelerates the nucleation of T1-phase and promotes the formation of the precipitation free zones(PFZ), and increases the strength and decreases the plasticity of the alloy.

Temperature field analysis of main steam pipe under local post weld heat treatment

In local post weld heat treatment, the temperature difference is the criterion of the process. The temperature field in the main stream pipe under local post weld heat treatment is simulated by finite element method. A close-loop control program is designed to simulate the temperature field of two different pipes. Both the skin effect of induction heating and electro-thermal coupled effect are considered in the heating model. The local heat treatment temperature difference at the inner and outer side of the pipe is analyzed and the different convection conditions are also considered. The simulation results show that in appropriate induction heating process, the temperature difference in the pipe can be controlled within 30 ℃.

Effect of homogenization treatment in electric field on microstructure and properties of 1420 Al-Li alloy

In comparison with the homogenization treatment without an electric field prior to the same solid solution and aging treatment, the homogenization treatment in an electric field increases the hardness and strength of 1420 Al Li alloy, but somewhat decreases the elongation of the alloy. Moreover, the elongation of the alloy increases with the homogenization temperature in an electric field increasing. TEM observation showed that the homogenization treatment in an electric field can accelerate the dissolution of the coarse particles of second phase on the grain boundary as well as make δ′phase precipitated in subsequent aging process finer and more numerous.

Surface Treatment of Polypropylene Films Using Dielectric Barrier Discharge with Magnetic Field

Atmospheric pressure non-thermal plasma is of interest for industrial applications. In this study, polypropylene （PP） films are modified by a dielectric barrier discharge （DBD） with a non-uniform magnetic field in air at atmospheric pressure. The surface properties of the PP films before and after a DBD treatment are studied by using contact angle measurement, atomic force microscopy （AFM） and X-ray photoelectron spectroscopy （XPS）. The effect of treatment time on the surface modification with and without a magnetic field is investigated. It is found that the hydrophilic improvement depends on the treatment time and magnetic field. It is also found that surface roughness and oxygen-containing groups are introduced onto the PP film surface after the DBD treatment. Surface roughness and oxygen-containing polar functional groups of the PP films increase with the magnetic induction density. The functional groups are identified as C-O, C=O and O-C=O by using XPS analysis. It is concluded that the hydrophilic improvement of PP films treated with a magnetic field is due to a greater surface roughness and more oxygen-containing groups.

Field Comparison of the Impact of Different Treatment Durations in the Treatment of Acute Otitis Externa

Background: Acute otitis externa is a common multi-factorial disorder in the dog. Several topical preparations are available on the veterinary market, which are licensed for an either specified duration of treatment or for a discretionary period that is determined by the clinician. Objectives: To compare the efficacy of two topical products, both licensed for the treatment of otitis externa in the dog, but with different treatment durations. Animal Population: One hundred and sixty dogs were enrolled in this multicentre field study from which 157 dogs were analysed in the Per Protocol sample (73 Aurizon?treated animals and 84 Easotic?treated animals). Method: Dogs were randomly assigned to Aurizon?or Easotic?treatment groups. Aurizon?(Vétoquinol SA: marbofloxacin, clotrimazole, dexamethasone) was administered daily in the affected ear(s) for 7 or 14 days, and was compared with a daily administration of Easotic?(Virbac SAS: gentamicin, miconazole, hydrocortisone aceponate) for 5 days. General and localised clinical signs were scored on days 0 (D0), 3 (D3), 7 (D7), 14 (D14) and 21 (D21). Results: Clinical cure rates at the end of treatment were 56.3% and 48.8% (p=0.35) in the Aurizon?and Easotic?groups respectively and 81.2% versus 74.7% one week after completing the course of treatment (p = 0.34). Twenty-one days after initially presenting for the study, cure rates were 84.3% in the Aurizon?group and 73.8% in the Easotic?(p=0.12). A relationship between severity of clinical signs and treatment duration was observed. Conclusion and Clinical Significance: At the end of the trial period, cure rates showed a tendency to be higher in the Aurizon?treated animals. The flexible dosage and the veterinary monitoring permitted treatment duration to be adjusted based upon the severity of otitis externa thus increasing the likelihood of clinical cure.

INFLUENCE OF HOMOGENIZATION TREATMENT UNDER AN ELECTRIC FIELD ON DUCTILITY OF 2091 Al－Li ALLOY DURING HOT ROLLING

For 2091 Al-Li alloy, the volume fraction of second phase particles is greatly determined by the homogenization temperature and homogenization time under an electric field and the ductility of the alloy is determined by the fraciton of second phase particles. The combined homogenization treatment shortens the homogenization time, reduces the loss ofLi content and increases the ductity of the alloy.

EFFECT OF HOMOGENIZATION TREATMENT UNDER AN ELECTRIC FIELD ON T_1 DISTRIBUTION AND MECHANICAL PROPERTIES OF 2091 Al－Li ALLOY

Homogenization treatment under an electric field increases the distributive homogeneity of the T1 precipitation and improves the yield strength of 2091 Al-Li alloy.

1-MCP结合低压静电场复合处理对红托竹荪保鲜效果的影响

为探究不同保鲜方式对红托竹荪贮藏品质的影响,该文以四川宜宾“红托竹荪”为试验材料,采用1-甲基环丙烯(1-methylcyclopropene,1-MCP)缓释贴纸、低压静电场(low voltage electrostatic field,LVEF)处理方式将红托竹荪贮藏于4℃,相对湿度75%的冷库,分析其对红托竹荪外观品质、生理指标、营养成分和相关酶活性的影响,并结合相关性分析和主成分分析探讨红托竹荪贮藏期间品质差异。贮藏12 d后,与对照组相比,1-MCP+LVEF组可以缓解硬度下降和质量损失,有效提高还原糖、总酚和可溶性蛋白质含量等营养物质保有率,显著减轻膜脂过氧化的程度,维持细胞完整性。主成分分析提取出2个主成分,累积贡献率达到95.14%,结果表明,失重率、硬度、还原糖、抗坏血酸过氧化物酶活性等是影响红托竹荪贮藏品质的关键指标。综上,1-MCP+LVEF处理能够更好地维持红托竹荪的采后贮藏品质。该研究旨在为红托竹荪保鲜技术的开发提供理论依据,为红托竹荪储运销售提供新的思路。

The Impact of Small Field’s Off-Set on Output Factor in Intensity Modulated Radiation Treatment

In intensity modulated radiation treatment (IMRT) planning, the use of asymmetrically collimated fields that are placed on central axis or its off-set is mostly required. Output is the main topic discussed today for extremely small and/or severe irregularly shaped fields. The air scatter data are involved directly or indirectly in obtaining the output. Despite the fact that extensive data have been published in many studies to provide a guide on the magnitude of output factor for clinical accelerators, there are very few data reviewed about output factor in-air or phantom for off-set fields. This study was aimed to investigate the impact of these conditions for small fields. This study was conducted in Elekta Synergy linear accelerator which produces 6 MV X-ray energy. The in-air output factor (Sc) has been measured by CC04 ion chamber with brass-alloy “build-up” cap and Dose-1 electrometer, and the total output (Scp) measurements were carried on at dose maximum depth in phantom by the same chamber and Thermoluminescence dosimeter (TLD) for 1 - 10 cm2 fields. The all measurements at center of isocenter and off-set fields at three directions (X2, Y1, Diagonal) were done. By decreasing field size from 10 to 2 cm2 at isocenter, the Sc value using CC04 was decreased to 5.4% and Scp using CC04 and TLD to 14.5% and 11% respectively. By increasing off-set value, the Sc and Scp values were increased in all directions comparing to central fields. The maximum increase was obtained in Y1 direction for Sc and Scp. TLD results for Scp is slightly higher than CC04. The dosimetric properties of small fields and their off-set should be evaluated and modelled appropriately in the treatment planning system to ensure accurate dose calculation in Intensity Modulated Radiation Treatment.

Exploring magnetic field treatment into solid-state fermentation of organic waste for improving structural and physiological properties of keratin peptides

This study systematically investigated the effects of a low-intensity magnetic field on the influence of keratinase activity, peptide yield, and structural and functional properties of peptides produced during solid-state fermentation (SSF) of mixed organic substrates (chicken feather powder and okara) using a mutant strain of Bacillus licheniformis. Initially, the magnetic field-assisted SSF (MSSF) conditions were optimized, which provided the optimized conditions as the number of treatments 3 at every 24 h (24, 48, and 72 h) with 4 h holding time at 120 Gs of magnetic intensity (mI). Under the optimum conditions, keratinase activity and peptide production increased by 10.31% and 13.77%, respectively. Further, in order to evaluate the influence of magnetic field treatment on the peptides, MSSF experiments were done under different mI conditions (40, 80, 120, and 160 Gs), followed by the evaluation of the structural changes of the extracted peptides. The structural analysis revealed that mI had a significant impact on the keratin surface. In contrast, secondary structure analysis confirmed the unfolding of the peptide with decreased α-keratin and increased β-keratin, thereby boosting the bioactive properties of the peptides. The highest hydroxyl free radical (.OH), 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging and Fe2+ chelating rates (56.55, 71.36, and 50.72%, respectively) were found at 120 Gs, which were insignificant with the results at 160 Gs. Therefore, MSSF has a positive effect on the proteolysis mechanism, which can increase bioactive peptide production from keratin.

航空制件燃气热处理炉的炉内温度均匀性

在热处理航空制件的过程中,热处理炉温度的均匀性对其质量与性能具有直接影响.以大尺寸燃气热处理炉为研究对象,先采用热电偶测试测得在不同工作温度下的热处理炉温度均匀性指标,然后基于热处理炉的具体尺寸和运行参数,采用Fluent软件进行数值模拟,得到热处理炉全场的温度分布情况,最后通过调节烧嘴与壁面的夹角,对典型工况下全场温度的均匀性进行优化.结果表明:该航空制件燃气热处理炉的上层温度在各保温时刻较为稳定,且随着保温温度的升高,热处理炉各段炉温的均匀性均得到明显改善;温度场的仿真模拟值与现场实测值相差较小,该有限元模型较为可靠.本研究结果可为热处理炉温度均匀性的改进设计提供一定的理论参考.

Manufacturing of Surface Nanostructured Fibers Featuring an Antibacterial Effect by Magnetic Field Transportation of Magnetite@Silver Core-Shell Nanoparticles

Magnetic core-shell nanoparticles of type Fe3O4@Ag were synthesized in gram scale following a combined co-precipitation phase-transfer method and afterwards, processed to nanoparticle polymer (polypropylene and polyamide) composites. These composites were used as sheath material for the fabrication of core-sheath fibers. During the melt spinning process, a magnetic field was applied around the roving, whereby the particles move in the still liquid sheath polymer towards the surface. The produced fiber materials were investigated by AFM showing a nanostructuring of the surface, which was indirectly confirmed by determination of a slight surface tension lowering. Nanoparticle movement was shown by cross-section SEM and EDX measurements. The antibacterial activity of the spun fibers was proven by contacting them with Escherichia coli. A long-term stability of this effect was observable by carrying out a standard washability test. In contrast to previous works this new approach uses no deposition technique to introduce surface changes. It rather applies a magnetic force to move appropriately equipped nanoparticles from the inside of the fiber to the surface. This leads in only one step to a strong superficial anchoring of the particles resulting in a unique combination of long-term stable antibacterial and improved anti-soiling effects.

Combined action of low temperature and magnetic field of different intensities on growth of some bacterial species <i>in vitro</i>

Growth dynamic of bacterial population after influence of magnetic field and cryoaction has been studied. In vitro experiments were performed on Bacillus cereus, Staphylococcus aureus, and Lactobacillus delbrueckii cultures. The most significant result was obtained in experiments with Bacillus cereus. When applied separately, cryoaction and alternating magnetic field were not able to kill this microorganism, whereas combined action of these factors led to the complete devitalization of bacterial culture.

THE IMPROVEMENT OF ELECTRON FIELD EMISSION FROM AMORPHOUS CARBON FILMS DUE TO HYDROGEN PLASMA CHEMICAL ANNEALING EFFECT

Hydrogenated amorphous carbon films were fabricated by using layer-by-layer deposition method and hydrogen dilution method in a small d.c.-assisted plasma enhanced chemical vapor deposition system. It was found that the hydrogen plasma treatment could change the sp2/sp3 ratio to some extent by chemical etching. The improvements of field emission characteristics were observed compared with that from conventionally deposited a-C films, which can be attributed to the large field enhancement effect due to the inhomogeneous distribution of nanometer scale sp2 clusters and the reduction of the surface emission barrier due to the hydrogen termination.

Effect of Electromagnetic Compound Treatment on Microstructure and Performance of Cemented Carbide

In order to study the effect of electromagnetic compound treatment on the mechanical property, cutting performance and microstructure of cemented carbide, the samples were treated by a self-made electromagnetic compound treatment device with different magnetic field strength(H=1, 1.25 and 1.5 T). The electromagnetic compound treatment method was proposed to couple pulsed magnetic field and pulsed current. The results show that after the pulsed magnetic field treatment, the values of the transverse rupture strength of the samples were respectively reduced by 21%, 20.6% and 20.1%;the cutting performance was decreased by about 4.5%, which means the tool life was decreased. After the electromagnetic compound treatment, the values of the transverse rupture strength of the rectangular samples were respectively increased by 8%, 8.6% and 9.5%, and the tool life was increased by 4.2%, 7% and 10.3%. After the electromagnetic compound treatment, the pulse current provided the driving force for dislocation motion. A strong pulse current driving force is more likely to make the dislocation multiply and slip. A high density dislocation cell is formed within the material, so the mechanical properties were significantly increased.

A NEW TREATMENT FOR INTERFACE OF METAL AND DIELECTRIC IN FDTD METHOD

A new treatment for interface of metal and dielectric in finite-difference time domain (FDTD) method was presented, further how and why this treatment should be as it is was explained. The FDTD method was developed to compute the low-frequency electromagnetic fields in the metal instead of the traditional high-frequency ones as it was originally proposed. The computational results agreed well with the experimental ones.

EFFECT OF TEMPERING IN PULSE MAGNETIC FIELD ON MICROSTRUCTURE AND MECHANICAL PROPERTIES OF HIGH SPEED STEEL

Using a self-made pulse magnetic field heat treatment equipment with low or medium intensi- ty,the tempering process of high speed steel W6Mo5Cr4V2 was investigated.It was found that the secondary hardening process and the transformation of retained austenite for the steel were accelerated by the pulse magnetic field,and the tempering period could be reduced to half of the original.It was shown by the analyses of X-ray and eletron microscopy that the precipitation of carbides becomes more homogeneous and dispersive,and the tetragonality of martensite increases obviousely,which causes the improvement of hardness and red-hardness for the steel.It was confirmed that the service life of tools as centre bits,screw taps and punches for nuts could be increased by 0.4 to 1.4 times by the tempering in magnetic field.

高海拔严寒地区隧道冻害研究现状及展望

针对高海拔严寒地区隧道冻害问题,结合隧道冻害的相关研究,从冻害类型及原因分析、冻害机制、温度场、处置措施等4个方面的现状进行阐述和分析,对当前研究存在的不足和未来的发展方向进行探讨。主要成果为:1)通过对高海拔严寒地区隧道工程实例进行分析,总结4种冻害类型及4种冻害原因;2)基于含水风化层冻胀理论、整体性围岩冻胀理论、衬砌背后积水冻胀理论、裂隙水冻胀理论等4种冻胀理论,建立多年冻土区以整体性围岩冻胀理论为主、季冻区以裂隙水冻胀理论为主的多理论联合分析的方法;3)温度场研究方法分为现场监测、理论解析、模型试验、数值模拟等4种,其中现场监测是对洞内外温度进行监测,而理论分析、模型试验、数值模拟则是对监测结果进行验证分析;4)冻害处置措施有防排水措施、保温防寒措施、抗冻措施等3种,防冻的关键是将三者相结合进行综合治理;5)指出冻害机制适用性、温度场研究方法现状、处置措施适用性等方面的不足,未来应在高海拔严寒地区建立多种冻胀理论、多种研究方法综合应用的研究体系,并在隧道防排水、保温防寒、抗冻等方面给出处置措施。