Correlation between microstructure and mechanical properties of columnar crystals in the directionally solidified Mg-Gd-Y-Er alloy

The Mg-4.58Gd-0.45Y-0.01 Er alloys with different volume fractions of columnar crystals in hard orientation(orientation factor ofbasal plane slip system is less than 0.2)were prepared by changing the pulling rate to regulate the crystal growth orientation.Tensile tests were performed on the Mg-4.58Gd-0.45Y-0.01 Er alloy at room temperature,and the structure after deformation was investigated by electron backscatter diffraction(EBSD).Subsequently,the strengthening mechanism of columnar crystals in hard orientation was explored.The results show if orientation factors ofbasal plane slip system of columnar crystals are all greater than 0.4(soft orientation),the alloy has low yield strength σ_(s)(64 MPa),but great work hardening ability,and ultimate tensile strength σ_(b) and elongationδare 114 MPa and 37.3%,respectively.If orientation factors ofbasal plane slip system of columnar crystals are all less than 0.2(hard orientation),the alloy has high strength(σ_(s),125 MPa),but poor plasticity(δ,6.32%).If the"hard orientation"and the"soft orientation"columnar crystals are arranged alternately along the direction perpendicular to the crystal growth,the alloy has both superior strength(σ_(s),102 MPa)and excellent plasticity(δ,22.5%)at room temperature.The improved comprehensive mechanical property can be attributed to two factors.On the one hand,the"hard orientation"columnar crystals can prevent the"soft orientation"crystals deforming,so the strength is improved.On the other hand,the"hard orientation"columnar crystals themselves can withstand a certain amount of deformation to retain appropriate plasticity.

Investigation of mechanical properties of twin gold crystal nanowires under uniaxial load by molecular dynamics method

Twin gold crystal nanowires, whose loading direction is parallel to the twin boundary orientation, are simulated.We calculate the nanowires under tensile or compressive loads, different length nanowires, and different twin boundary nanowires respectively. The Young modulus of nanowires under compressive load is about twice that under tensile load.The compressive properties of twin gold nanowires are superior to their tensile properties. For different length nanowires,there is a critical value of length with respect to the mechanical properties. When the length of nanowire is greater than the critical value, its mechanical properties are sensitive to length. The twin boundary spacing hardly affects the mechanical properties.

Structural, electrical, and optical properties of ZnInO alloy thin films

Indium zinc oxide （IZO） thin films with different percentages of In content （In/[In＋Zn]） are synthesized on glass substrates by magnetron sputtering, and the structural, electrical and optical properties of IZO thin films deposited at different In2O3 target powers are investigated. IZO thin films grown at different In2O3 target sputtering powers show evident morphological variation and different grain sizes. As the In2O3 sputtering power rises, the grain size becomes larger and electrical mobility increases. The film grown with an In2O3 target power of 100 W displays the highest electrical mobility of 13.5 cm.V-1-s-1 and the lowest resistivity of 2.4× 10^-3 Ω.cm. The average optical transmittance of the IZO thin film in the visible region reaches 80% and the band gap broadens with the increase of In2O3 target power, which is attributed to the increase in carrier concentration and is in accordance with Burstein-Moss shift theory.

Effects of the sputtering power on the crystalline structure and optical properties of the silver oxide films deposited using direct-current reactive magnetron sputtering

This paper reports that a series of silver oxide （AgzO） films are deposited on glass substrates by direct-current reactive magnetron sputtering at a substrate temperature of 250 ℃ and an oxygen flux ratio of 15：18 by modifying the sputtering power （SP）. The AgxO films deposited apparently show a structural evolution from cubic biphased （AgO ＋ Ag20） to cubic single-phased （Ag20）, and to biphased （Ag20 ＋ AgO） structure. Notably, the cubic single-phased Ag20 fihn is deposited at the SP = 105 W and an AgO phase with （220） orientation discerned in the Ag^O films deposited using the SP 〉 105 W. The transmissivity and refiectivity of the AgxO films in transparent region decrease with the increase the SP, whereas the absorptivity inversely increases with the increase of the SP. These results may be due to the structural evolution and the increasing film thickness. A redshift of the films＇ absorption edges determined in terms of Tauc formula clearly occurs from 3.1 eV to 2.73 eV with the increase of the SP.

Density functional theory analysis of electronic structure and optical properties of La-doped Cd_2SnO_4 transparent conducting oxide

The electronic structural, effective masses of carriers, and optical properties of pure and La-doped Cd2SnO4 are calculated by using the first-principles method based on the density functional theory. Using the GGA＋U method, we show that Cd2SnO4 is a direct band-gap semiconductor with a band gap of 2.216 eV, the band gap decreases to 2.02 eV and the Fermi energy level moves to the conduction band after La doping. The density of states of Cd2SnO4 shows that the bottom of the conduction band is composed of Cd 5s, Sn 5s, and Sn 5p orbits, the top of the valence band is composed of Cd 4d and O 2p, and the La 5d orbital is hybridized with the O 2p orbital, which plays a key role at the conduction band bottom after La doping. The effective masses at the conduction band bottom of pure and La-doped Cd2SnO4 are 0.18m0 and 0.092m0, respectively, which indicates that the electrical conductivity of Cd2SnO4 after La doping is improved. The calculated optical properties show that the optical transmittance of La-doped Cd2SnO4 is 92%, the optical absorption edge is slightly blue shifted, and the optical band gap is increased to 3.263 eV. All the results indicate that the conductivity and optical transmittance of Cd2SnO4 can be improved by doping La.

低温高速永磁电机硅钢片铁心电磁性能变化机理研究

由于低温泵用高速电机工作在低温环境中,探究低温环境对构件材料性能的影响、低温条件对电机特性的作用机理以及形成统一的选材原则已经成为该类电机亟待解决的问题。采用实验法在常温(25℃)和低温(-196℃)条件下对不同系列的冷轧无取向硅钢片的电磁性能进行了研究,分析了低温环境与频率对硅钢片电磁性能的影响情况。基于实测数据并采用有限元法计算了电机定子铁耗,得到了电机采用不同系列硅钢片的定子铁耗分布以及变化情况。为了探究低温环境下采用不同系列硅钢片时电机定子铁耗变化幅度不同的原因,采用低温冲击法对硅钢片的矫顽力进行测量,验证了有限元计算所得规律的正确性。探明低温条件对硅钢片电磁性能的影响机理,提出低温高速高频电机铁心材料的选材建议,为低温工作环境下低温电机铁心材料选材提供理论借鉴与参考。

酶法提取竹虫蛋白的工艺优化及其性质

为提高竹虫利用率,以竹虫为原料,考察不同酶、pH值、提取温度、提取时间、液料比、加酶量对竹虫蛋白提取率的影响,通过响应面试验优化提取工艺,并测定竹虫蛋白的功能特性。结果表明:采用胃蛋白酶酶解,pH2.0、提取温度40℃、提取时间2.0 h、液料比12.5∶1(mL/g)、加酶量1.0%时提取工艺最佳,此时竹虫蛋白提取率为21.00%。竹虫蛋白对DPPH·、ABTS^(+)·清除率的IC_(50)分别为0.43 mg/mL和0.66 mg/mL,其起泡性、乳化性和乳化稳定性良好。

不同生态修复方式对内蒙古荒漠草原露天矿山土壤肥力的影响

为了探究不同修复方式对内蒙古露天受损矿区土壤的修复效果,分别用植生袋修复、生态包修复、植生毯修复、自然恢复和客土改良5种生态修复方式对乌海露天矿区受损土壤进行修复,测定修复后土壤的理化性质并进行主成分分析,采用内梅罗肥力指数和IFI指数评价修复后土壤的肥力.结果表明:①与原生植被相比,植生袋修复后土壤的有机质、水解氮、速效钾、速效磷含量显著增多(P<0.05),分别升高了1361.11%、742.73%、294.74%、124.36%;内梅罗肥力指数和IFI指数分别为2.00和1.16,显著高于其他修复方式(P<0.05),修复效果最好.②主成分分析结果显示,有机质、水解氮、铵态氮、速效钾以及全钾含量是研究区土壤生态修复效果的主要限制因子.

不同土壤肥力下苏北水蜜桃最佳有机肥用量研究

本研究以国家地理标志性农产品苏北新沂水蜜桃为供试材料,选取当地低肥力和中等肥力土壤果园的代表性地块,以常规施肥为对照,研究在化肥减量25%的基础上增施不同用量有机肥(30、45、60、75 t/hm^(2))对新沂水蜜桃产量、品质、经济效益、土壤理化性质及肥料利用效率等的影响,以期为新沂水蜜桃果园的有机肥施用提供技术指导。结果表明,在两种基础肥力不同的土壤上,增施有机肥较常规施肥水蜜桃均表现出增产提质的趋势。综合成本核算后,与常规施肥相比,在中等肥力土壤上,增施60 t/hm^(2)有机肥可获得最大的经济收益(增加8100元/hm^(2));而在低肥力土壤上,增施有机肥较常规施肥经济效益降低,这种相对亏损随着有机肥施用量的增加而递减。推测增施超过60 t/hm^(2)的有机肥或连续多年施有机肥有望获得更大的经济效益。无论是何种基础肥力土壤,当年增施有机肥在提高水蜜桃产量与品质、改善土壤理化性质方面均表现出潜力,推测这种改善效益可能通过连续多年施用有机肥来显著体现。这两个推测均有待于进一步验证。

基于PMC指数模型的知识产权政策评价研究

随着创新驱动发展战略深入实施,知识产权对国家治理体系现代化和高质量发展的作用日益凸显,完备科学的知识产权政策评价模型,有助于现行政策体系优化和未来政策制定。本文选取中央及省、自治区、直辖市出台的29个知识产权“十四五”规划政策,基于扎根理论和PMC指数模型,构建知识产权“十四五”规划政策评价模型,测算各政策文本的PMC指数并绘制PMC曲线图,从政策评价等级、四大地区政策、城市群政策等多个视角进行对比分析。研究表明:中国知识产权“十四五”规划政策体系整体质量良好,部分政策存在政策视野受限、政策覆盖面不足等问题,对新发展背景下知识产权发展的需求回应力度不足。基于此,提出强化政策协同性、健全政策评估体系、构建多主体参与机制等对策建议。

二硫键对自修复水性聚氨酯机械性能的影响

本文比较了二硫键和C-C键在水性聚氨酯力学性能和自修复能力方面的区别,并探讨了二硫键对于线形和交联结构聚氨酯的影响。结果表明,虽然二硫键可以显著加速聚氨酯的自修复时间和提高自修复率,但是也会对聚氨酯的强度、断裂伸长率、抗蠕变与抗松弛等力学性能造成不利影响。对于需要在工作温度下进行自修复的交联结构材料,应当慎重考虑二硫键对蠕变及应力松弛的影响。此外,线形聚合物可以通过分子链热运动实现修复而无需动态共价键的支持,而对于交联结构聚氨酯,动态共价键则能显著提高其自修复能力。

企业存在最优金融化水平吗?——基于主营业务经营风险的考察

本文以2012—2021年我国A股上市公司为研究样本,对企业是否存在最优金融化水平进行考察。研究发现,企业以追求主营业务经营风险最小化为目标时,存在最优金融化水平,且在金融生态环境较好的企业和非国有企业中,最优金融化水平相对更高。检验表明,当企业金融化不足时,金融化通过提高研发投入降低主营业务经营风险;当企业金融化过度时,金融化通过提高金融资产收入占比增大主营业务经营风险。由此可见,企业应依据经营决策目标不断调整金融投资比例,以实现最优金融化,最大限度地发挥金融服务实体经济的职能。

Mechanical Evaluation of AZ80 Magnesium Alloy in Cast Wrought Form

Wrought magnesium alloy AZ80 with a thick section of 20 mm was prepared by squeeze casting (SC) and permanent steel mold casting (PSMC). The porosity measurements of the SC and PSMC depicted that SC AZ80 had a pore content of 0.52%, which was 77% lower than 2.21% of PSMC AZ80 counterpart. The YS, UTS, ef, E and strengthening rate of cast AZ80 were determined by mechanical pulling. The engineering stress versus strain bended lines showed that SC AZ80 had a YS of 84.7 MPa, a UTS of 168.2 MPa, 5.1% in ef, and 25.1 GPa in modulus. But, the YS, UTS and ef of the PSMC AZ80 specimen were only 71.6 MPa, 109.0 MPa, 1.9% and 21.9 GPa. The findings of the mechanical pulling evidently depicted that the YS, UTS, ef and E of SC AZ80 were 18%, 54%, 174% and 15% higher than PSMC counterpart. The computed resilience and toughness suggested that the SC AZ80 exhibited greater resistance to tensile loads during elastic deformation and possessed higher capacity to absorb energy during plastic deformation compared to the PSMC AZ80. At the beginning of permanent change, the strengthening rate of SC AZ80 was 10,341 MPa, which was 9% greater than 9489 MPa of PSMC AZ80. The high mechanical characteristics of SC AZ80 should be primarily attributed to its low porosity level. .

《国有企业资产与产权变动档案处置办法》的主要内容、实践价值及相关问题的思考

论文在系统介绍《国有企业资产与产权变动档案处置办法》的主要内容的基础上,进一步说明了该标准的主要特点、理论意义和实践价值,并对该部门规章在个别行文表述和某些规定的细化等方面存在的不足,提出了修改和完善的建议。

虾青素基无氟超疏水彩色颗粒合成及其着色抗湿胶布的制备

通过对虾青素、虾青素/茜素及虾青素/指甲花醌色素进行修饰处理,在共轭色素上原位生长超支化聚合物纳米级结构,以构筑虾青素基无氟超疏水彩色颗粒。基于热黏合法制备出具有彩色外观以及自清洁特性的着色抗湿胶布,并在麻布扭面、塑料凹面、玻璃凸面和陶瓷V面进行黏贴性应用。采用红外光谱、X射线衍射谱图、表面元素含量检测等手段,对虾青素基无氟超疏水彩色颗粒及其着色抗湿胶布进行了化学信息表征,通过扫描电子显微镜和透射电子显微镜对彩色颗粒的微观结构及其组成进行了观察。将着色抗湿胶布与商品化透明胶带进行对比,发现前者具有更耐久的黏贴性能。

阳离子型抗静电剂的合成及其性能

针对PET材料的静电积聚问题,合成了无规共聚物结构的非离子与阳离子型抗静电剂,重点考察了阳离子型抗静电剂中的季铵盐组分对抗静电剂的热学性能、抗静电性能的影响,以及阳离子型抗静电剂的含量对PET基体的抗静电性能、表面亲水性能以及力学性能的影响。结果表明:阳离子型抗静电剂的热稳定性不如非离子型抗静电剂;阳离子型抗静电剂的抗静电效果优于非离子型抗静电剂,当季铵盐的添加量为14%时,阳离子型抗静电剂的抗静电效果相对最优;当阳离子型抗静电剂质量分数达到20%时,PET注塑样品的表面电阻率下降了4个数量级,表面接触角下降了63.03%,抗静电性能以及表面亲水性能得到显著提高,但力学性能有所下降。

“非遗+”模式下民间文学艺术作品知识产权保护理论与实践探析——以辽宁省为例

【目的】探寻新时代背景下加强民间文学艺术作品知识产权保护的路径,推动《民间文学艺术作品著作权保护条例(征求意见稿)》的出台。【方法】对辽宁省在非物质文化遗产保护模式下的创新型探索进行分析。【结果】民间文学艺术作品在当今时代下具有发展和保护并行的趋势,但在保护上仍然存在理论逻辑冲突等法律保护问题与局限性。【结论】针对保护的困境问题,分析民间文学艺术作品的自身特性,对存在问题的内在逻辑与局限性进行分析,提出明确权利主体、细化法律衔接等民间文学艺术作品知识产权保护路径。

基于机器学习方法对人类基因组DNA双链断裂位点进行识别

DNA双链断裂(double-strand break,DSB)是细胞中一种严重的DNA损伤形式,与包括癌症、重组异常、神经元发育异常在内的多种基因组不稳定性疾病密切相关。由于成本和技术门槛的限制,高通量测序技术绘制的高分辨率DSB图谱十分有限,这阻碍了我们对不同物种基因组中DSB情况的认知。据此,我们建立了以随机森林(RF)、支持向量机(SVM)和逻辑回归(LR)三种分类器为基础算法的分类预测模型,对人类上皮细胞基因组DSB位点进行预测。除了之前预测研究中常用到的表观特征和DNA形状特征外,我们发现DNA序列特征(k-mer频数、GC含量、GC-偏移和互信息)也能表征DSB位点。同时,在考虑DNA物理性质、化学位移和自相关信息后,预测结果得到有效提高。将上述所有特征合并后进行预测,得到了较好的分类预测结果,其中逻辑回归(LR)的分类预测性能是最佳(AUC=0.97),与以往的预测结果相当(AUC=0.964)。另外,通过特征递增搜索方法,得到由294个特征组成的最优特征集,对应的AUC值达到0.974。

无压烧结SiC/TiB_(2)复合材料组织与性能的研究

以TiB_(2)为基体、SiC为主要添加相、B_(4)C和纳米炭黑为烧结助剂,采用无压烧结方法制备SiC/TiB_(2)复合材料,研究SiC添加量对SiC/TiB_(2)复合材料的显微组织、力学性能及体积电阻率的影响。结果表明:随着SiC含量的增加,复合材料的晶粒尺寸逐渐减小,开口气孔率逐渐降低,抗折强度、断裂韧性及维氏硬度均呈现上升趋势;当SiC的质量分数为20%时,复合材料的力学性能最佳,此时其抗折强度、断裂韧性和维氏硬度分别为189.5 MPa、4.19 MPa·m^(1/2)和15.8 GPa;随着SiC含量的增加,复合材料的体积电阻率增大,导电性能有所降低。

解除强制隔离戒毒人员侵财类犯罪预防研究——基于470例裁判文书的统计分析

据中国裁判文书网的相关案例数据显示,解除强制隔离戒毒人员,除了实施与先前吸毒行为相关联的毒品犯罪外,犯罪数量排名第二的犯罪类型就是侵财类犯罪。因此,通过对解除强制隔离戒毒人员侵财类犯罪的案例数据和案例内容进行统计分析,总结其犯罪成因和犯罪预防困境,能够有针对性地提出相应预防对策,从而有效维护社区治安稳定和人民生命财产安全,切实帮助此类人员真正回归社会,感受社区温暖,重获阳光人生。