热磁处理对牛乳中酶活力及蛋白组成的影响

中国黑白花奶牛混合鲜乳，高速离心脱脂后以５０～１００℃加热或磁化１５分仲，测定乳中三种酶活力，并采用ＳＤＳ－ＰＡＧＥ观察乳蛋白组成变化，结果表明：经７Ｏ℃以上热处理后牛乳中碱性磷酸酶（ＡＫＰ）基本失活，乳过氧化物酶（ＬＰ）和纤溶蛋白酶（Ｐｌａｓｍｉｎ）相对较稳定，需８０℃以上加热，磁化处理对乳中酶活力影响不一致，脱脂乳经磁化后三种酶活力稍有提高，磁化底物使纤溶蛋白酶活力增加６０％以上。磁化处理对乳３０℃保温２０小时后滴定酸度影响不显著。牛乳中白细胞内ＡＫＰ比活力为０．０２４单位／毫克蛋白，ＬＰ比活力为５．５６单位／毫克蛋白，极显著低于乳中酶的比活力，表明它们不是乳中ＡＫＰ和ＬＰ的主要来源。乳蛋白ＳＤＳ－ＰＡＧＥ分析表明，８０℃以上加热使乳牛α－乳清蛋白、β－乳球蛋白发生部分聚合，并对酪蛋白（ＣＳＮ）产生一定影响。磁化后乳中ＣＳＮ同热处理后乳ＣＳＮ电泳特性有相似之处，可能ＣＳＮ空间结构发生了变化。

二段热磁处理对Fe-Co-Cr合金磁性能和组织的影响

对于 Fe-30Cr-25Co-3.5Mo 合金提出由二段热磁处理和最终回火组成的处理,该处理与通常采用的单段热磁处理相比可以使矫顽力提高25-30%。对组织的研究证明,矫顽力的提高以磁性相按成分析出均匀度的提高为条件并与有效磁各向异性的增长有关。Fe-Co-Cr 系合金用于制造永磁体。为获得高的磁滞性能。

钴基非晶薄带交换偏置现象稳定性和可控性的研究

钴基(Co58Fe5Ni10Si11B16)非晶薄带在一定温度范围内做热磁处理之后,由于薄带内有少量磁性较硬结晶相析出,其磁矩对非晶软磁基体的钉扎作用使样品出现交换偏置行为。在研究过程中采用X射线衍射仪、高分辨透射电镜表征样品相组成及微观结构,利用冲击检流测量法测试其磁滞回线,通过扫描探针显微镜观测薄带表面磁畴,由此深入分析内在磁矩配置情况。结果表明,在利用横向冲击场调控钴基薄带交换偏置行为的过程中存在临界场。当横向冲击场低于临界场时,结晶相磁矩几乎不受其影响,交换偏置行为呈稳定状态;而大于临界场时,结晶相磁矩在其冲击作用下按自由能最小原则重新配置,交换偏置行为可通过调节横向冲击场的大小有效调控。

Influence of hydrogen content on room temperature compressive properties of Ti-6Al-4V alloy at high strain rate

Electromagnetic forming tests were done at room temperature to reveal the influence of hydrogen content on the compressive properties of Ti-6Al-4V alloy at high strain rate. Microstructure was observed to reveal the mechanism of hydrogen-enhanced compressive properties. The experimental results indicate that hydrogen has favorable effects on the compressive properties of Ti-6Al-4V alloy at high strain rate. Compression of Ti-6Al-4V alloy first increases up to a maximum and then decreases with the increase of hydrogen content at the same discharge energy under EMF tests. The compression increases by 47.0% when 0.2% (mass fraction) hydrogen is introduced into Ti-6Al-4V alloy. The optimal hydrogen content for cold formation of Ti–6Al–4V alloy under EMF was determined. The reasons for the hydrogen-induced compressive properties were discussed.

Study on Thermomagnetic Treatment Fe-25.5Cr-12Co Permanent Magnetic Alloy

The magnetic properties and microstructure in a low cobalt Fe-25.5Cr-12Co alloy by different process of thermomagnetic treatment were investigated. It is found that magnetic properties are sensitive to parameters of thermo- magnetic treatment process in magnetic field, including temperature, time and applied magnetic field. There are optimized isothermal aging temperature and time in different magnetic heat treatment conditions. High magnetic field strength could improve magnetic properties. Applied magnetic field has a great effect on microstructure of the Fe-25.5Cr-12Co alloy. The finer ferromagnetic d] particles with suitable c/a ratio by high magnetic field magnetic heat treatment are attributed to improvement the magnetic properties.

Recent advances of electromagnetic interference shielding Mg matrix materials and their processings:A review

In terms of lightweight electromagnetic interference(EMI)shielding structural materials,Mg matrix materials have proven to be the best,due to their exciting properties(e.g.low density,high specific strength,good electrical conductivity and excellent EMI shielding properties)and their wide range of applications in lightweighting in electronics,automotive and aerospace industries.Through processing,such as alloying,heat treatment,plastic deformation and composite processing,Mg matrix materials can be obtained with tailorable properties which can play a key role in designing materials for EMI shielding.This work introduces an overview of the research on the EMI shielding properties of Mg matrix materials as well as their EMI shielding mechanisms over the past few decades,focused on the influence of alloying,heat treatment,plastic deformation and composite processing for the EMI shielding properties of Mg matrix materials.At the end,conclusions and future perspectives are provided.

Microstructure ＆ texture evolution and magnetic properties of high magnetic-induction 6.5% Si electrical steel thin sheet fabricated by a specially designed rolling route

Electrical steel sheets with 6.5%(mas fraction) Si with good shapes and superior magnetic inductions were successfully produced by a specially designed processing route including ingot casting, hot rolling and warm rolling both with interpass thermal treatment, and final annealing. The sheets were of 0.2 mm and 0.3 mm thick over 140 mm width. A detailed study of the microstructural and textural evolutions from the hot rolling to annealing was carried out by optical microscopy, X-ray diffraction and electron backscattered diffraction. The hot rolled sheet characterized by near-equiaxed grains was dominated by the mixture of <001>//ND fiber(λ-fiber), <110>//RD fiber(α-fiber) and <111>//ND fiber(γ-fiber) textures owing to the partial recrystallization and strain induced boundary migration(SIBM) during the hot rolling interpass thermal treatment. The static recovery and SIBM during the warm rolling interpass thermal treatment result in large and elongated warm rolling grains. The warm rolling texture is dominated by obvious λ, Goss and strong γ-fiber textures. The application of the interpass thermal treatment during hot and warm rolling significantly enhances the impact of SIBM during annealing, which is responsible for the formation of the moderate λ-fiber, some near-λ fiber texture components and the obviously weakened γ-fiber texture in the annealed sheet, leading to a higher magnetic induction compared to the commercially produced 6.5% Si steel by chemical vapor deposition(CVD).

Ag nanoparticles preparation and their light trapping performance

Ag nanoparticles were fabricated on Si substrates by radio-frequency magnetron sputtering and thermal annealing treatments.It was found that Ag nanoparticles are ellipsoid at low annealing temperature,but the axis ratio decreases with the increase of annealing temperature,and a shape transformation from ellipsoid to sphere occurs when the temperature increases to a critical point.The experimental results showed that the surface plasmon resonances depend greatly on the nanoparticles'shape and size,which is in accordance with the theoretical calculation based on discrete dipole approximation.The results of forward-scattering efficiency(FSE) and light trapping spectrum(LTS) showed that Ag nanoparticles annealed at 400°C could strongly enhance the light harvest than those annealed at 300 and 500°C,and that the LTS peak intensity of the former is 1.7 and 1.5 times stronger than those of the later two samples,respectively.The conclusions obtained in this paper showed that Ag ellipsoid nanoparticles with appropriate size is more favorable for enhancing the light trapping.