基于降低ISI和ICI的小波分组调制结构的研究

从降低误码率和系统复杂度的角度,探讨了基于降低ISI和ICI的小波分组调制结构的优化方法。首先考虑小波分组调制结构本身对调制信号性能的影响,粗选出具有较小ISI和ICI的结构,然后考虑无线信道对调制信号的影响,利用最小均方误差方法,进一步优选出与信道相匹配的树结构,从而实现小波分组调制结构优化的目的。仿真结果表明,所选择的小波分组树结构更加简单,降低了系统的复杂度,同时提高了小波分组调制系统的抗干扰性能。     

系统化的变电专业新员工岗位技术技能提升措施探究

本文提出了系统化的变电专业新员工岗位技术技能提升措施,能有效发挥专业分部的统筹作用及延伸师傅带徒弟的长处,由系统化的专业技术技能提升要求及可操作性强的各项操作演练措施组成,有效加速变电专业新员工实操技术技能提升速度。     

Discussion on the Mechanism of Source Integration between Solar Energy and Biomass Energy with Similar Grades

The clean transformation of the China's energy structure is related to the establishment of China as an energy power in the new world pattern. The multi-energy systems based on renewable energy, especially solar energy and biomass energy, have become a popular energy supply mode. However, there is no clear theoretical guidance for the quantitative source integration of these two types of clean energy. Concretely, whether the source grades of solar energy and biomass energy are similar in different solar energy modes has not been considered yet. Aiming at this problem, based on the theory of space-time unity of the special theory of relativity, a new principle of source integration is proposed, and the corresponding mathematical model is established. The theoretical calculation of the combination of solar energy and different types of biomass energy is carried out. Under the premise of the similarity between the source grades of different biomass energy and solar energy, the specific solar energy concentration ratio is obtained. According to this principle, the matching efficiency of the multi-energy integration for rice and corn plants can be increased by 39.2% and 36.2%, respectively.     

Hot deformation behavior and processing map development of AZ110 alloy with and without addition of La-rich Mish Metal

In order to compare the workability of AZ110 alloy with and without addition of La-rich Mish Metal(MM), hot compression tests were performed on a Gleeble-3500 D thermo-mechanical simulator at the deformation temperature range of 473-623 K and strain rate range of 0.001-1 s-1. The flow stress, constitutive relation, DRX kinetic model, processing map and microstructure characterization of the alloys were investigated. The results show that the flow stress is very sensitive to deformation temperature and strain rate, and the peak stress of AZ110 LC(LC = La-rich MM) alloy is higher than that of AZ110 alloy.The hot deformation behavior of the alloys can be accurately predicted by the constitutive relations. The derived constitutive equations show that the calculated activation energy Q and stress exponent n for AZ110 alloy are higher than the calculated values of AZ110 LC alloy. The analysis of DRX kinetic models show that the development of DRX in AZ110 LC alloy is earlier than AZ110 alloy at the same deformation condition. The processing maps show that the workability of AZ110 LC alloy is significantly more excellent than AZ110 alloy and the microstructures are in good agreement with the calculated results.The AZ110 LC alloys can obtain complete DRX microstructure at high strain rate due to its higher stored energy and weak basal texture.     

粉末冶金无镍奥氏体不锈钢的渗氮研究

在粉末冶金无镍奥氏体不锈钢的烧结冷却过程中,以气体渗氮方式对其进行渗氮处理.通过对其渗氮层金相组织的观察及力学性能和耐腐蚀性能的测试,结果表明,随着渗氮温度的升高,奥氏体不锈钢随炉冷却时析出物增多,其表层氮含量和表面硬度先增加后趋于平缓,抗弯强度先增加后下降并趋于稳定,而耐腐蚀性降低.     

精准温控贮藏对西兰花采后品质和生理变化的影响

为了探究西兰花在不同贮藏温度下的生理变化与品质差异,分别用普通冰箱[(4.0±1.0)℃]、精准温控的冰温库[(-0.5±0.3)℃]和相温库([(-0.4±0.1) ℃]3种环境贮藏采摘后的西兰花。结果表明:经过冰箱冷藏的西兰花贮藏期可达30d,30d后可溶性固形物、叶绿素、维生素C、可溶性蛋白含量下降,品质逐渐劣变;精准温控(冰温与相温)贮藏的西兰花70d后色泽饱满,营养物质含量丰富,呼吸强度与乙烯生成速率较小,且腐烂率与黄化指数处于较低水平,体现较高的超氧化物歧化酶及过氧化氢酶活性,膜质受损程度较轻、机体防御体系较强。冰温与相温贮藏60d时,西兰花维生素C质量分数分别为37.70、46.53mg·100g-1,黄酮质量分数分别为12.30、15.56mg·100g-1,过氧化氢酶活性分别为67.20、120.00U·g-1;在70d时,西兰花呼吸强度分别为463.79、416.90mg·(kg·h)-1,乙烯生成速率为83.37、63.07μL·(kg·h)-1,超氧化物歧化酶活性分别为1543.91、1588.55U·g-1。相比较冰温,相温贮藏能延缓西兰花维生素C及黄酮含量下降,抑制其呼吸强度和乙烯生成速率,使得超氧化物歧化酶和过氧化氢酶活性处于较高水平(P<0.05)。精准温控(冰温与相温)贮藏可控制西兰花的生理变化,有效延缓其采后品质下降的速率,相温贮藏优于冰温贮藏。     

微/纳米结构含锌硅酸钙基涂层成骨性能研究

骨科植入物涂层的表面形貌和化学组成对炎症反应的进程和骨形成的发生都发挥着重要调节作用。为综合利用微/纳米仿生结构和生物活性元素的优势,将含锌(Zn)的纳米结构物质引入到经水热处理后的等离子喷涂硅酸钙(calcium silicate, CS)涂层表面,对所制备涂层的物相组成、表面和截面形貌、比表面积、Zeta电位和生理环境下离子溶出等物理化学性能进行了表征。相比于常规CS涂层,具有微/纳米复合结构的CS和含锌CS涂层拥有更高比表面积和孔容,可吸附更多血清蛋白和纤维连接蛋白,通过刺激细胞内整合素以及下游vinculin和FAK基因表达,提高了骨髓间充质干细胞(BMSCs)铺展能力。涂层中锌的引入进一步提高了其表面BMSCs的增殖能力和与成骨细胞分化相关的基因表达。具有微/纳米复合结构的涂层明显上调了RAW264.7巨噬细胞中M2表型因子(CD206和ARG)基因表达,而涂层中溶出的Zn²⁺显著提高了RAW264.7细胞中抑炎症因子(IL-1ra和IL-10)基因表达,促使其向抑炎症表型转化。骨科植入物涂层表面锌元素和纳米结构的引入有利于创建良好的骨免疫微环境,促进骨...     

热轧双相钢的发展现状及高强热轧双相钢的开发

介绍了热轧双相钢的发展现状及存在问题,指出低成本热轧双相钢、高延伸凸缘型铁素体+贝氏体热轧双相钢(F-B热轧双相钢)及高强度热轧双相钢的开发及应用,将促进我国热轧双相钢的发展,推动汽车工业的"以热代冷"进程。同时,探讨了纳米析出强化型热轧双相钢的强化机理及工艺控制原理,并在实验室进行了中试,开发出铁素体基体析出强化型的热轧双相钢,其抗拉强度达770~830 MPa,屈强比0.75,组织为铁素体+马氏体,且铁素体基体中存在大量细小的纳米级尺寸的TiC过饱和析出和相间析出。     

基于深度学习的采摘机器人目标识别定位算法

为了提升采摘机器人对果实的识别准确率以及定位定精度,提出一种基于深度学习Faster-RCNN框架的采摘机器人目标识别和定位算法.首先采用卷积神经网络VGG16模型提取输入图像的特性信息,并利用区域提议网络RPN生成含有目标的候选框,通过引入自适应候选框数的方法有效提升了算法性能,然后利用多任务损失函数对目标进行分类识...     

基于高密度电阻率法的露天铁矿采空区探测的研究

露天铁矿开采区地下浅部大量采空区的存在,给矿山的人员及生产安全带来极大的威胁。为保证生产活动的顺利进行,必须对采空区进行精确探测。由于高密度电阻率法较常规电法具有信息丰富、精度高的特点,运用该法对露天铁矿采空区进行探测,结合数据反演断面图,在地下50m的范围内,共划定采空区四处,并精确划定采空区顶底板深度、水平范围和展布方向,为矿山的治理工作提供了可靠依据。并且在分析采集数据的基础上,总结出视电阻率识别模型及其主要特点,为地下采空区的划定提供了理论基础。