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1.
In the present paper,we study the restricted inexact Newton-type method for solving the generalized equation 0∈f(x)+F(x),where X and Y are Banach spaces,f:X→Y is a Frechet differentiable function and F:X■Y is a set-valued mapping with closed graph.We establish the convergence criteria of the restricted inexact Newton-type method,which guarantees the existence of any sequence generated by this method and show this generated sequence is convergent linearly and quadratically according to the particular assumptions on the Frechet derivative of f.Indeed,we obtain semilocal and local convergence results of restricted inexact Newton-type method for solving the above generalized equation when the Frechet derivative of f is continuous and Lipschitz continuous as well as f+F is metrically regular.An application of this method to variational inequality is given.In addition,a numerical experiment is given which illustrates the theoretical result.  相似文献   
2.
The effect of ultrasound on the kinetics of anti-solvent crystallization of sucrose was studied. The influence of temperature, stirring rate, supersaturation and ultrasonic power on the anti-solvent crystallization of sucrose was investigated. The relationship between infrared spectral characteristic band of sucrose and supersaturation was determined with an online reaction analyzer. The crystal size distribution of sucrose was detected by a laser particle-size analyzer. Ultrasound accelerated the crystallization process, and had no impact on the crystal shape. Abegg, Stevens and Larson model was fitted to the experimental data, and the results were the following: At 298.15 K, the average size of crystals was 133.8 μm and nucleation rate was 4.87 × 109 m−3·s−1 without ultrasound. In an ultrasonic field, the average size was 80.5 μm, and nucleation rate was 1.18 × 1011 m−3·s−1. Ultrasound significantly reduced the average size of crystals and improved the nucleation rate. It was observed that the crystal size decreased with the increase of stirring rate in silent environment. When the stirring rate increased from 250 to 400 rpm, the average size decreased from 173.0 to 132.9 μm. However, the stirring rate had no significant impact on the crystal size in the ultrasonic field. In addition, the activation energy of anti-solvent crystallization of sucrose was decreased, and the kinetic constant of nucleation rate was increased due to the effect of ultrasound. In the ultrasonic field, the activation energy was reduced from 20422.5 to 790.5 J·mol−1, and the kinetic constant was increased from 9.76 × 102 to 8.38 × 108.  相似文献   
3.
氮和磷是水环境生物生长和繁殖必须的营养成分,影响水体初级生产力的水平,且水体富营养化水平与氮磷形态密切相关,随着水体环境的改变,沉积物会向水体释放氮磷,造成二次污染。同时,对外源氮磷污染来源的贡献进行定量识别,可有效管理和控制水体氮磷污染负荷。毗河和石亭江是沱江的重要支流,影响着长江母亲河的水质。采用钼锑抗分光光度法和连续提取法研究在枯水期和丰水期毗河和石亭江水体和表层沉积物中总氮(TN)、总磷(TP)及各形态氮磷的分布特性,对比不同土地利用类型河流氮磷行为特性及释放风险,并采用Multiple Linear Regression of the Absolute Principal Component Scores(APCS-MLR)受体模型进行氮磷污染源的识别和量化。研究结果表明:① 研究区水体和表层沉积物中氮磷均处于不同程度的污染水平,水体枯水期TP的主要贡献者是颗粒态无机磷(PIP)和颗粒态有机磷(POP),而丰水期却是颗粒态无机磷(PIP)和溶解态无机磷(DIP),两水期水体中TN的主要贡献者是硝态氮(NO-3-N)和有机氮(ON)。而在表层沉积物中,TP的主要贡献者是钙结合态磷(HCl-P),TN的主要贡献者是酸解态氮(HN)。在枯水期和丰水期,毗河表层沉积物生物有效磷(BAP)占TP的平均值(19.7%和23.0%)比石亭江的平均值(11.0%和12.5%)占比更高,具有较高的磷释放风险。研究发现,枯水期氮磷污染程度高于丰水期,而且石亭江的氮磷污染程度高于毗河。②APCS-MLR模型在毗河提取了城镇生活污水、生活垃圾堆积产生的渗滤液、动植物残体分解和养殖业废水4个污染源因子,其中城镇生活污水对毗河氮磷污染的贡献最大(枯水期50.9%,丰水期54.8%),而在石亭江提取了工业生产中产生的废水等、动植物残体的降解、农业废弃物的风化、农田排水渠的农业废水和农药化肥的不合理施用5个污染源因子,其中工业生产中产生的废水等对石亭江氮磷污染的贡献最大(枯水期58.7%,丰水期55.8%)。因此,当地相关部门应加强对高贡献污染源的管控,从而降低流域氮磷污染负荷。  相似文献   
4.
The reaction of N2 with trinuclear niobium and tungsten sulfide clusters Nb3Sn and W3Sn (n=0–3) was systematically studied by density functional theory calculations with TPSS functional and Def2-TZVP basis sets. Dissociations of N−N bonds on these clusters are all thermodynamically allowed but with different reactivity in kinetics. The reactivity of Nb3Sn is generally higher than that of W3Sn. In the favorite reaction pathways, the adsorbed N2 changes the adsorption sites from one metal atom to the bridge site of two metal atoms, then on the hollow site of three metal atoms, and at that place, the N−N bond dissociates. As the number of ligand S atoms increases, the reactivity of Nb3Sn decreases because of the hindering effect of S atoms, while W3S and W3S2 have the highest reactivity among four W3Sn clusters. The Mayer bond order, bond length, vibrational frequency, and electronic charges of the adsorbed N2 are analyzed along the reaction pathways to show the activation process of the N−N bond in reactions. The charge transfer from the clusters to the N2 antibonding orbitals plays an essential role in N−N bond activation, which is more significant in Nb3Sn than in W3Sn, leading to the higher reactivity of Nb3Sn. The reaction mechanisms found in this work may provide important theoretical guidance for the further rational design of related catalytic systems for nitrogen reduction reactions (NRR).  相似文献   
5.
Xiao-Xia Yang 《中国物理 B》2022,31(7):78901-078901
Under the background of Covid-19 sweeping the world, safe and reasonable passenger flow management strategy in subway stations is an effective means to prevent the spread of virus. Based on the social force model and the minimum cost model, the movement and path selection behavior of passengers in the subway station are modeled, and a strategy for passenger flow management to maintain a safe social distance is put forward. Take Qingdao Jinggangshan Road subway station of China as the simulation scene, the validity of the simulation model is verified by comparing the measured value and simulation value of the time required for passengers from getting off the train to the ticket gate. Simulation results indicate that controlling the time interval between incoming passengers at the entrance can effectively control the social distance between passengers and reduce the risk of epidemic infection. By comparing the evacuation process of passengers under different initial densities, it is found that the greater the initial density of passengers is, the longer the passengers are at risk social distance. In the process of passenger emergency evacuation, the stairs/escalators and ticket gates are bottleneck areas with high concentration of passenger density, which should be strictly disinfected many times on the basis of strictly checking the health code of incoming passengers and controlling the arrival time interval. The simulation results of this paper verify the harmfulness of passenger emergency evacuation without protective measures, and provide theoretical support for the operation and management of subway station under the epidemic situation.  相似文献   
6.
物理教学离不开理想化模型的建构,简化的理想模型能够帮助中学生在现有知识层面的基础上,更好地理解相关知识并解决问题.但是在实际物理问题中,如果不充分考虑理想化条件,学生在解决问题时就容易产生认知矛盾,不知所措.以一个有趣的静电场问题为例,揭示理想化模型的局限性,强调"去理想化"思维习惯的重要性.探讨分析了教师如何帮助学生打破思维定势,让其对已掌握的物理知识活学活用,培养学生严谨的科学思维.  相似文献   
7.
双电解液锂空气电池因其高理论能量密度受到广泛研究,但电池正极侧氧还原反应(ORR)速率低,其反应速率是限制锂空气电池发展的主要因素之一.本文提出了以钌(Ru)掺杂单层石墨烯作为正极ORR催化剂,采用第一性原理计算nRu (n=1~3)掺杂石墨烯的电子结构和氧气在Ru掺杂石墨烯表面的吸附性能,并以过渡态搜索方法获得ORR反应路径,研究碱性溶液中Ru掺杂单层石墨烯作用下的ORR机理.研究结果表明,经Ru原子掺杂后,石墨烯能够获得稳定的掺杂结构,且电导率显著提升.同原始单层石墨烯相比,Ru掺杂石墨烯增强了对O2的吸附能力.在三Ru(n=3)掺杂石墨烯表面进行的ORR无需克服任何能垒.此外,三Ru掺杂石墨烯表面对OH基团的吸附能最低,有利于ORR的连续进行.研究表明三Ru掺杂石墨烯有望成为一种新型的ORR催化剂以提高双电解液锂空气电池的性能.  相似文献   
8.
9.
暴露于硫酸盐环境中的混凝土输水管易遭受硫酸盐化学侵蚀,导致其耐久性退化、提前失效;而环境中硫酸根离子传输进入混凝土是其化学侵蚀的前提.为获得混凝土内硫酸根离子的扩散进程,首先基于Fick定律及质量守恒定律,建立饱和混凝土管内硫酸根离子的扩散-反应模型.其次,将扩散-反应模型的边界条件齐次化,建立其有限元控制方程.然后,开展硫酸钠溶液中水泥砂浆圆柱试件的腐蚀试验,测定试件不同深度处的硫酸根离子浓度,与模型计算结果对比,以验证模型.最后,开展数值模拟研究,分析混凝土输水管外表面、内外表面暴露于浓度恒定或振荡的硫酸盐溶液情况下管内硫酸根离子浓度的时空分布.  相似文献   
10.
光谱质量、样本个体差异、检测系统和建模算法等多种因素共同决定水果糖度检测模型的预测精度和稳定性。采用自主研发的短积分全透射近红外在线检测系统以5 ms积分时间和0.5 m·s-1运行速度在线获取了“富士”苹果全透射光谱信号。不同姿态获取的透射光谱强度差异明显,但曲线走势相近,均在920 nm波段具有最大的光谱强度,在850 nm波段存在波谷。采用移动平均平滑、标准正态变量变换和多元散射校正等预处理方法有效去除原始光谱的随机噪声和基线偏差,减小了样本检测姿态引起的光谱差异。为分析不同检测姿态对苹果整果糖度预测模型的影响,构建了单一姿态局限模型和多姿态通用模型,结果表明基于全位点平均透射光谱构建的单一姿态局限模型对检测姿态具有很大的局限性,而多姿态通用模型预测能力较单一检测姿态相当,但却对不同的检测姿态具有更强的适用能力。为进一步提高光谱信号质量,优化模型预测能力,采用信号强度阈值优选方法实现了苹果整果糖度预测模型优化,发现移除中央位点获取的透射光谱信号,有利于提高苹果整果糖度预测模型精度。多姿态通用信号强度优化模型综合考虑不同姿态获取的光谱信息有效性,有效提升了通用信号强度优化模型的预测能力和稳定性,当多姿态通用模型中信号强度阈值为5 000时,模型预测性能最佳,其预测参数Rp,RMSEP和RPD分别为0.79,0.84%和1.58。表明短积分全透射近红外在线检测系统用于不同姿态苹果糖度预测是可行的,多姿态通用模型的建立,扩大了模型在不同姿态的预测稳健性,短积分光谱采集方式结合信号强度阈值优选方法提升了光谱信号的质量和模型的预测能力。  相似文献   
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