Grain size characteristics of the carbonate-free fraction of surface sediments from the Southwest Indian Ridge area and its geological significance

The carbonate-free fraction of 20 surface sediments collected from the ultraslow-spreading Southwest Indian Ridge(SWIR) was studied by grain size analysis and mineralogical analysis with X-ray powder diffraction(XRD),stereo microscopy and scanning electron microscopy(SEM). The characteristics of the carbonate-free fraction of the sediments were obtained, and related influential factors were discussed. The results show that the mean grain size of this fraction is in 1.96Φ–8.19Φ, with poorly sorting and unimodal, bimodal or irregular bimodal distribution patterns. Four grain size end members of the fraction are derived with the End Member Model method. The finest end member EM1 shows a significant contribution of terrigenous materials of the aeolian input and sediment carried by the bottom current. End member EM2 with medium size mainly reflects sediment of a siliceous bioclast origin. EM3 and EM4 are interpreted as representing the coarser volcanic materials related to bedrock weathering or volcanic activities. Multi-provenance is the dominant factor controlling the grain size pattern of the carbonate-free fraction of the sediments in that area. In addition, sediment transport processes such as the bottom current and wind are the minor factors that influence the grain size distribution of the carbonate-free fraction sediments.

Study on grain refinement of interstitial-free steel during continuous frictional angular extrusion

To explore the application of severe plastic deformation for grain refinement in steel production, a new method called continuous frictional angular extrusion （CFAE） was applied to refine the grain of interstitial-free steel. The deformation was carried out at room temperature and individual sheet specimens were processed in different number of passes. An overall grain size of 200nm was achieved after 8 passes and the proportion of high-angle boundaries to the total boundaries was more than 60%. Through the characterization of high resolution EBSD, X-ray diffraction （XRD） and hardness testing,this paper discussed the evolution of microstructures and textures during deformation and explored the development direction of the method.

A new model for electromigration grain boundary noise based on free volume

Grain boundary plays a key role in electromigration process of polycrystal interconnection. We take a free volume to represent a ＇vacancy-ion complex＇ as a function of grain boundary specific resistivity, and develop a new characterisation model for grain boundary noise. This model reveals the internal relation between the boundary scattering section and electromigration noise. Comparing the simulation result with our experimental result, we find the source as well as the form of noise change in the electromigration process. In order to describe the noise enhancement at grain boundary quantitatively, we propose a new parameter--grain boundary noise enhancement factor, which reflects that the grain boundary noise can characterise the electromigration damage sensitively.

Study of surface cell Madelung constant and surface free energy of nanosized crystal grain

Surface cell Madelung constant is firstly defined for calculating the surface free energy of nanosized crystal grains, which explains the physical performance of small crystals and may be greatly beneficial to the analysis of surface states and the study of the dynamics of crystal nucleation and growth. A new approximative expression of the surface energy and relevant thermodynamic data are used in this calculation. New formula and computing method for calculating the Madelung constant α of any complex crystals are proposed, and the surface free energies and surface electrostatic energies of nanosized crystal grains and the Madelung constant of some complex crystals are theoretically calculated in this paper. The surface free energy of nanosized-crystal-grain TiO2 and the surface electrostatic energy（absolute value） of nanosized-crystal-grain α-Al2O3 are found to be the biggest among all the crystal grains including those of other species.

Study of Surface Cell Madelung Constant and Surface Free Energy of Nanosized Crystal Grain

Surface cell Madelung constant is firstly defined in calculating surface free energy of nanosized crystal grains, which explains the physical performance of small crystals and may be great benefit to make surface analysis and study dynamics of crystal nucleus growth. A new approximative expression of surface energy and relevant thermodynamic data was used in this calculation. A new formula and computing method for calculating the Madelung constant a of any complex crystals is proposed, and surface free energies and surface electrostatic energies of nanosized crystal grains as well as Madelung constant of some complex crystals are theoretically calculated in this paper. The surface free energy of nanosized crystal grain TiO2 and surface electrostatic energy（absolute value） of nanosized crystal grain α-A12O3 are found to be the biggest among other crystal grains.

Teff, Buckwheat, Quinoa and Amaranth: Ancient Whole Grain Gluten-Free Egg-Free Pasta

This report demonstrates innovative ancient whole grains, gluten-free, egg-free pasta (no chemicals added) made using a kitchen counter-top appliance. Whole grain, fusilli pasta was prepared with teff, buckwheat, quinoa and amaranth flours. These ancient grains are called “Super Foods” due to their ideal essential amino acids and mineral profiles. Dough formulations contained 95% whole grain flour and 5% guar gum. Taste panels of 62 in-house volunteers judged amaranth pasta significantly (p ≤ 0.05) higher in color/appearance than other pastas tested. Odor/aroma of buckwheat pasta and texture/mouth-feel of teff pasta were significantly better than quinoa and amaranth pasta. Acceptance and taste/flavor of teff and buckwheat pasta were similar and significantly higher than quinoa and amaranth pasta (teff = buckwheat > quinoa > amaranth). The USDA food guide recommends that at least 1/2 of all the grains eaten should be whole grains. The FDA allows food Health Claim labels for food containing 51% whole gains and 11 g of dietary fiber per serving. Novel health promoting whole grain, good source of protein, gluten-free, egg-free (no chemicals added) pasta had acceptance of teff 87%, buckwheat 82%, quinoa 61% and amaranth 15%. Amaranth pasta needs improvement in several sensory attributes by fortification, processing and/or use of other cultivars for the desired results. Ancient whole grain, gluten-free, egg-free pasta would increase whole grain consumption and offer a healthy option to vegetarians as well as to gluten sensitive individuals.

Ancient Whole Grain Gluten-Free Flatbreads

This is the only report demonstrating innovative ancient whole grain gluten-free (no yeast or chemicals) products. Ancient whole grain gluten-free flatbreads were prepared with quinoa, teff, amaranth and buckwheat flours. Dough formulations contained flour, salt and water. Ingredients were mixed for 5 min using table top Kitchen Aid mixer at stir setting 1. Dough was equilibrated for 30 min. 65 g of dough was placed between two sheets of nonstick parchment paper and pressed to 17 cm round flatbreads in a Tortilla Chapatti Press. Each flatbread was cooked for two minutes (one minute each side) in using Flatbread Maker. Taste panels of 64 inhouse volunteers determined that Taste/Flavor of quinoa, teff and amaranth flatbreads were similar and significantly (P ≤ 0.05) better than those for buckwheat flatbread. The taste panel determined ancient whole grain gluten-free flatbreads had acceptance of quinoa 84%, teff 72%, amaranth 66% and buckwheat 38%. Each ancient whole grain gluten-free flatbread contained 25 - 30 g whole grain and 4 - 5 g protein. Quinoa, teff and amaranth one flatbread contained 2 - 3 g dietary fiber, whereas buckwheat flatbread contained 8 g dietary fiber. Consuming two whole grain gluten-free flatbreads with two meals (total = 4) would give 4 - 32 g of dietary fiber. The USDA food guide recom mends that at least 1/2 of all the grains eaten should be whole grains. The FDA allows food Health Claim labels for food containing 51% whole gains and 11 g of dietary fiber. The gluten sensitive individuals would enjoy tasty, health promoting, ancient whole grain easy to make flatbreads. These recipes offer consumers additional nutritious gluten-free choices and would lead to in crease in whole grain consumption.

晶粒细化对免热处理压铸铝合金组织与性能的影响

采用光学显微镜和电子拉伸试验机,研究了晶粒细化对免热处理压铸铝合金显微组织、流动性和力学性能的影响。结果表明:随着铝钛硼合金添加量的逐渐增加,压铸铝合金的α-Al晶粒逐渐从粗大的树枝状细化成细小的颗粒状和近球形状,压铸铝合金的流动性试样长度、抗拉强度和断后伸长率逐渐升高。添加0.25%的铝钛硼合金,压铸铝合金的流动性试样长度为947 mm,抗拉强度为295.6 MPa,断后伸长率为8.5%,与未添加铝钛硼合金相比,压铸铝合金的流动性试样的长度增加了10.9%,抗拉强度提高了7.1%,断后伸长率提高了14.9%。

CALCULATION OF SECOND PHASE PARTICLE-GRAIN BOUNDARY INTERACTION RANGE

On the basis of the grain boundary equation by HeUman and corresponding analysis of Worner, this article deals with the interaction range between the second-phase particle （SPP） and grain boundary （GB） as viewed from the applicability of grain boundary equation. Also, a new expression describing the interaction range has been derived, which solves the problem in theory that the interaction range between SPP and GB can only be qualitatively analyzed previously. It is shown that given the interaction position between SPP and GB, the interaction range can be quantitatively determined by use of this expression.

The Impact of Hydrothermal Treatments on Technological Properties of Whole Grains and Soriz (<i>Sorghum oryzoidum</i>) Groats

Cereals and cereal products are the basic element in ensuring the food security of the population. Most cereal-based foods contain gluten. Nutritional therapy is the only treatment for people with gluten-related disorders. No gluten-free products are manufactured in the Republic of Moldova, and the imported ones are sold at very high prices. In this context, Moldova is an unexplored field and research is required. The paper investigated the impact of hydrothermal treatments on whole grains and sorghum groats. It was found that whole grains and sorghum groats have a cooking time of about 130 and 40 minutes, respectively, which can be reduced by about 2 times by prior hydration in water. Hydration media and their concentrations (NaCl solutions;sol. NaHCO3 and C6H8O7 concentrations 0.5%;1.0% and 2.0%) differently influence the cooking time, mass, volume and firmness of the grains.

Research on the comprehensive performance of PrFeB magnets for synchrotron radiation and free electron laser

PrFeB magnets, which possess excellent magnetic properties at low temperatures, have important application value as cryogenic permanent magnet undulators for synchrotron radiation sources and free electron lasers. In this research study, several high-performance PrFeB magnets(P42H, P48SH, and P48UH) were prepared, and their performance was comprehensively examined, including evaluations of their magnetic properties,microstructures, uniformity, and stability. Next,their application prospects were analyzed and discussed. In China, the first cryogenic permanent magnet undulators(CPMUs) with P48SH magnets with 18 mm cycle lengths have been developed. When the temperature is 80 K and the gap is 6.0 mm,the magnetic field measurement results of the CPMU showed that the effective magnetic field peak was approximately 0.92 T, yielding an increase of 11.76% relative to operation at 300 K, with an RMS phase error of about 4.99°.

铝合金细化剂细化行为研究现状与展望

晶粒细化处理能够显著改善铝合金的综合性能,对拓展其应用领域意义重大。本文基于异质形核,探讨了点阵错配模型、边边匹配模型以及自由生长模型,肯定了边边匹配模型在筛选潜在晶粒细化剂方面的高效性;根据自由生长模型关于异质相尺寸、形态、分布等对晶粒细化效果影响的理论研究,归纳了物理、化学方法调控第二相进而优化细化效果的研究进展,并且对第二相尺寸影响细化效果的原因进行了理论阐述,最后对优化晶粒细化剂的方向做了展望。

全球农业贸易规则演变与中国粮食安全战略

当前,全球农业贸易规则正从多边治理向多边—双边双重治理转换、由低标准治理向高标准治理提升、由边境规则向边境内规则拓展、由规则协调刚性向包容并蓄转变,这是全球地缘政治经济格局变动下国家竞争的结果。文章重点考察了农业贸易规则演变对中国粮食安全的影响。研究发现,农业市场准入规则加剧了粮食贸易逆差,投资规则可能诱发跨国公司在华垄断,高标准SPS规则降低了农产品竞争力,而知识产权保护、环境保护、电子商务、竞争中性等边境内规则对中国粮食安全产生了多重影响。在此基础上,文章从构建全球自由贸易区网络、主动对接和积极构建农业贸易规则、构建竞争有序的粮食市场体系、加强外商投资的引导与监管、加快培育国内粮食龙头企业、完善粮食安全应急保障机制等六个方面提出强化粮食安全的战略举措。

温度梯度下Zr晶界迁移的分子动力学研究

定向退火技术广泛应用于提升高温合金综合性能,其构建温度梯度环境驱动晶界定向迁移,获得性能优异的柱状晶组织。然而,不同晶界的迁移能力差异较大,对柱状晶组织的形成造成阻碍。为了更好的调控定向退火工艺,本研究采用分子动力学方法对α-Zr中多个晶界在温度梯度下的迁移行为进行研究,归纳不同晶界在迁移过程中能量变化特征与迁移行为之间的规律,阐明超额势能与预熔温度等因素影响晶界迁移的机理。研究发现,原子势能越高则迁移激活焓越低,预熔温度越低则驱动力越大,晶界越容易发生迁移。这一发现可为解释温度梯度环境下晶粒的异常长大与晶界的停止迁移提供理论依据,为更好调控此类合金微观组织、获得均匀柱状晶提供理论参考。

不同改性技术在无麸质荞麦食品中的应用

荞麦作为重要的无麸质谷物,具有较高的营养价值和药用功效,是乳糜泻和麸质过敏患者重要的饮食来源。荞麦中淀粉含量高,缺少面筋蛋白,口感粗糙苦涩,导致其加工出的产品存在感官品质、质构特性差等缺陷,从而限制了荞麦类作物的加工品质与应用价值。为了开发优质的无麸质荞麦产品,需要采用合理的工艺技术提高荞麦的加工食用品质,开发出满足不同人群营养特性的荞麦食品。文章综述了生物酶催化、微生物发酵、胶体复配、挤压膨化、超高压处理、超微粉碎在荞麦加工中对其质构特性、流变特性、感官特性、营养特性的影响。旨在推动我国荞麦产业的发展,针对麸质过敏等特殊人群,开发多种品质良好、营养俱佳的荞麦制品。

牛栏山二锅头酒醅发酵过程中游离氨基酸含量、理化指标及酵母菌数变化

该研究以牛栏山二锅头白酒酿造过程中的酒醅为实验材料,利用超高效液相色谱(UPLC)分析不同发酵阶段酒醅中游离氨基酸含量的动态变化,同时对酒醅发酵过程中酵母菌数量、乙醇含量、总酸和pH值的动态变化进行分析。结果表明,酒醅发酵过程中酵母菌数量呈现先增加后减少的趋势,最高为77.7×10^(6)CFU/mL;乙醇含量整体呈现上升趋势,最高为6.61 mL/100 g;总酸含量增加,由0.54 g/g增至5.27 g/g;pH不断降低,由4.77降至3.28。酒醅发酵过程中共检测到15种游离氨基酸,总含量呈现先上升后下降的趋势,发酵第17天时达到最高值232.93 mg/g,发酵结束时含量最高的3种游离氨基酸为丙氨酸(34.40 mg/g)、脯氨酸(33.09 mg/g)、精氨酸(19.74 mg/g)。

压延率对无氧铜板高温退火的组织及性能影响

高导热AMB陶瓷基板的覆铜厚板性能直接影响基板的电性能和力学性能。通过对无氧铜原料板的加工、微观组织调整以及陶瓷与铜板的活性焊料复合,达到AMB陶瓷覆铜基板最优的组织状态和电学与力学性能。首先对无氧铜板原料进行450℃和650℃再结晶退火0.5 h处理,得到两种原始的铜板组织。其次,对原始铜板进行压延率为15%、30%、45%、60%、75%的压延和800℃/1 h的退火处理,研究了退火铜板的微观组织及力学性能和电学性能。结果表明:当压延率在15%~75%时,随着压延率增加,晶粒逐渐被拉长变成扁平状,再变成纤维状;硬度随着压延率增加逐渐增大,铜板的延伸率逐渐减小,抗拉强度在压延率为15%~60%时逐渐增大,压延率达到75%时出现了小幅度降低。当在800℃退火1 h后,铜板表面晶粒尺寸随着压延率的增加逐渐减小,晶粒分布更加均匀,其大小稳定在400~800μm之间。铜板在压延率为15%~60%时的抗拉强度基本保持不变;当压延率到达75%时,抗拉强度出现小幅度降低。铜板硬度随着压延率增加基本保持不变。当压延率从15%变为75%时,铜板的电阻率有小幅度上升。

不同发酵时间对沙米甜醅营养、感官品质及其酚类物质抗氧化活性的影响

为促进沙米作为食品原料的开发利用,以其为材料进行甜醅制作,探究不同发酵时间对沙米甜醅营养、食用品质及其酚类物质抗氧化活性的影响。结果表明,不超过12 h的短时发酵处理对沙米成分没有显著性(P>0.05)影响;处理时间大于12 h后,沙米甜醅的总酸、还原糖含量随处理时间延长显著增大(P<0.05),两者均在48 h后出现下降趋势,而游离氨基酸、总酚含量及其DPPH清除率一直呈现显著(P<0.05)升高趋势;36 h及以上的发酵处理可使沙米淀粉中抗性淀粉含量相比对照显著(P<0.05)增大,快速消化淀粉显著(P<0.05)降低;发酵处理使得沙米色泽偏红偏黄,饱和度增高;感官评价表明发酵48 h的沙米甜醅食用品质最佳。

Al-Zn-Mg-Cu合金加工过程组织演变研究

通过Jmatpro热力学计算、光学显微镜(OM)、扫描电子显微镜(SEM)及透射电子显微镜(TEM)研究了7175合金在加工过程中的组织演变。结果表明:7175铝合金热力学平衡相由Al Cr Mg Mn相、Mg2Si相、Al6Mn相、Al2Cu Mg相、Mg Zn2相和Al Cu Mg Zn相组成,实际状态下还含有少量的杂质相Al7Cu2Fe相。7175铝合金型材在挤压、固溶后组织主要为纤维状晶粒组织,没有明显的再结晶,在475℃下保温2.5 h后小尺寸的第二相基本回溶,大尺寸的未溶相为Al7Cu2Fe相和Mg2Si相,沿晶界呈链状破碎分布。弥散相Al Cr Mg Mn相在固溶和时效过程中一直存在,时效态晶内沉淀相为弥散分布的圆球状η′相和少量板状η相。晶界析出相MgZn2相断续分布,晶界无沉淀析出带(PFZ)宽度为35~45 nm。

信息系统访问控制的层次模型

信息系统访问控制用以在不同层次上要保护不同类型的客体对象。按照客体类型及其层次关系将访问控制逻辑分层处理,在不同层次上采取与客体特点相符的访问控制技术,从而形成一种访问控制的层次模型。在功能模块级采取基于角色的访问控制,而在数据对象级采用基于规则的实现方式。分层结构将复杂的访问控制分解为若干个在不同层次上易于处理的问题,降低了问题复杂性,并使得各层之间互相独立,灵活性好,易于实现、维护和扩展。