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71.
最近5年,大桥缆索用镀锌钢丝抗拉强度有了大幅提高,从1 770 MPa级、1 860 MPa级、1 960 MPa级到目前的2 000 MPa及以上级别,扭转指标有了颠覆性的改变,从之前的几转到目前的十几转、二十几转。论述了国内外钢铁企业生产大桥缆索镀锌钢丝用盘条的不同现状。从成分设计、生产工艺流程、盘条韧化处理方式和组织特点等方面进行阐述,讨论了国内外不同生产工艺特点及发展趋势,为中国大桥缆索镀锌钢丝用盘条的生产提供理论支持。  相似文献   
72.
Composites play important role in dental filling by controlling shrinkage along with correction in teeth's shape and position. Rehabilitation of severely worn dentition can be achieved using mechanically strong composites. This study aims to synthesize zirconia-based composites to be used as dental fillers. Effect of microwave powers (100–900?W) along with Fe3O4 doping are studied on the structural, mechanical and magnetic properties of stabilized zirconia. SEM and TEM reveal formation of spherical nanoparticles with diameter of ~30?nm. XRD results shows phase pure tetragonal zirconia (t-ZrO2) at microwave power of 500?W without any post heat treatment. Crystallite size calculated from XRD data (~23?nm) matches well with the previously reported value for stabilization of t-ZrO2. Microwave energy dissipation results in stresses causing volume shrinkage leading to monoclinic to tetragonal phase transformation with higher X-ray density and hardness of ~1347HV. VSM results show ferromagnetic response with low coercivity (600Oe) value and saturation magnetization (~2emu/g). It is worth mentioning here that this is one of its kind study reporting synthesis of room temperature stabilized Fe3O4 doped zirconia composites at microwave power of 500?W. Antibacterial studies reveal inhibition zone of ~32?mm against bacillus bacteria suggesting their potential use as dental filler.  相似文献   
73.
Xin-Na Geng  Danyu Bai 《工程优选》2019,51(8):1301-1323
This article addresses the no-wait flowshop scheduling problem with simultaneous consideration of common due date assignment, convex resource allocation and learning effect in a two machine setting. The processing time of each job can be controlled by its position in a sequence and also by allocating extra resource, which is a convex function of the amount of a common continuously divisible resource allocated to the job. The objective is to determine the optimal common due date, the resource allocation and the schedule of jobs such that the total earliness, tardiness and common due date cost (the total resource consumption cost) are minimized under the constraint condition that the total resource consumption cost (the total earliness, tardiness and common due date cost) is limited. Polynomial time algorithms are developed for two versions of the problem.  相似文献   
74.
Hydrolytic stability is an essential requirement for polyurethanes (PUs) that are used in highly humid and aqueous environments. In this study, hydrolysis-resistant PU elastomers (PUEs) are synthesized based on hydrophobic bio-based polyfarnesene diol (PFD), which contains unique “bottle brushes” structure (with long branched hydrocarbon side chains). The effect of hard segment (HS) content, ranging from 30 to 50%, on the morphology and properties of PUEs is investigated by Fourier transform infrared spectroscopy, thermogravimetric analysis, differential scanning calorimetry, X-ray diffraction, scanning electron microscopy, tensile, water absorption, and contact angle measurements. The results show that there are prominent phase separations in the synthesized PUEs. The PUEs show a three-stage degradation process and two Tg, one is at about −66 °C and the other 61 °C, which are related to the soft segment and HS, respectively. Water contact angles of PUEs increase from 98.6 to 105.2° with the increasing of PFD structural unit fraction. After being immersed in deionized water for 30 days, PUEs show no significant degradation of both tensile strength and elongation at break, and mass changes of all samples are less than 0.5%. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47673.  相似文献   
75.
《Ceramics International》2019,45(15):18876-18886
Red-emitting Sr0.8Ca0.19AlSiN3:0.01Eu2+ phosphor with halide fluxes for use in the production of white light-emitting diodes (white LEDs) with high-colour rendering indices (CRIs) was prepared through the high-temperature solid-state method. Fluoride (NaF, SrF2, BaF2, CaF2, AlF3·3H2O and CeF3), chloride (NH4Cl, BaCl2, MgCl2, NaCl and LiCl) and composite fluxes (NaF + SrF2, SrF2+NH4Cl and NaF + NH4Cl) were applied in the phosphors. NaF, SrF2, NH4Cl and NaF + SrF2 fluxes had prominent effects on the characteristics of Sr0.8Ca0.19AlSiN3:0.01Eu2+ phosphors. Sr0.8Ca0.19AlSiN3:0.01Eu2+ phosphors with various powder morphologies can be obtained through the addition of fluxes, which are conducive for phosphor formation. The powder morphologies of phosphors incorporated with NaF + SrF2 were preferable to those of powders incorporated with other fluxes. This result indicated that the incorporation of NaF + SrF2 into Sr0.8Ca0.19AlSiN3:0.01Eu2+ yielded phosphors with high luminescent intensity and quantum efficiency, excellent thermal stability, narrow full widths at half-maximum (FWHM, 75.2 nm), uniform rod-like morphologies with large particle sizes (D50 = 16.99 μm) and good particle dispersion. White LEDs with high CRIs were obtained by combining prepared phosphors (NaF + SrF2 additive) with the commercial green-emitting phosphors Y3(Al,Ga)5O12:Ce3+ and (Sr,Ba)2SiO4:Eu2+. White LEDs with Y3(Al,Ga)5O12:Ce3+ and (Sr,Ba)2SiO4:Eu2+ phosphors had correlated colour temperatures (CCTs) of 3064 and 3023 K, respectively, and CRIs of 81.8 and 92.4, respectively. Therefore, NaF + SrF2 can be used as a favourable flux for the production of Sr0.8Ca0.19AlSiN3:0.01Eu2+.  相似文献   
76.
77.
In this paper, we define a local version of Hudetz correction for the Yager entropy of dynamical systems. It is proved that the introduced function is indeed a local entropy map for the Hudetz correction of the Yager entropy, in the sense that, the Hudetz correction of the Yager entropy of a continuous map on a compact metric space is attained by integrating the introduced local entropy.  相似文献   
78.
摘要:为研究轧制过程中氧化物粒子对母材组织性能的影响,提出了一种只在再结晶区进行轧制的新工艺路线,利用常规冶炼及氧化物冶炼的实验钢分析其轧态显微组织、力学性能及相变过程。结果表明:在新轧制工艺下,氧化物冶金钢母材显微组织由常规的贝氏体板条束变为针状铁素体,其基体具有良好的力学性能,-80℃冲击韧性达149J;热轧工艺下的组织转变分两阶段进行,初期是针状铁素体的形核和晶粒细化,之后贝氏体相变被限制在针状铁素体板条间构成的区域内。  相似文献   
79.
The correct separation of chromosomes during mitosis is necessary to prevent genetic instability and aneuploidy, which are responsible for cancer and other diseases, and it depends on proper centrosome duplication. In a recent study, we found that Smy2 can suppress the essential role of Mps2 in the insertion of yeast centrosome into the nuclear membrane by interacting with Eap1, Scp160, and Asc1 and designated this network as SESA (S my2, E ap1, S cp160, A sc1). Detailed analysis showed that the SESA network is part of a mechanism which regulates translation of POM34 mRNA. Thus, SESA is a system that suppresses spindle pole body duplication defects by repressing the translation of POM34 mRNA. In this study, we performed a genome-wide screening in order to identify new members of the SESA network and confirmed Dhh1 as a putative member. Dhh1 is a cytoplasmic DEAD-box helicase known to regulate translation. Therefore, we hypothesized that Dhh1 is responsible for the highly selective inhibition of POM34 mRNA by SESA.  相似文献   
80.
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