奇异鞍点问题的NESS迭代法半收敛性分析

最近一些学者对于非奇异鞍点问题提出了一种新的外推移位分裂(NESS)预处理,并研究了NESS迭代方法的收敛性以及NESS预处理矩阵的谱分布。本研究进一步将NESS迭代方法用于求解奇异的鞍点问题,给出NESS迭代法在(1,1)块子矩阵是对称正定情况下的半收敛性分析。最后通过数值实验,验证了在适当参数下NESS迭代法求解奇异鞍点问题的可行性和有效性。

Influence of Light Rare Earth on Toughness of Welded Seam of LAHS Steel

The influence mechanism of light rare earth elements, which are transited to the welding seam of low-alloy high strength (LAHS) steel through the covering of t he electrode, on the toughness of the welding seam was studied. The experimental results show that proper amount of rare earth elements can desulfurate, dehydro genate, reduce inclusions and purify the structure of the welding seam. Rare ear th element additions have the effect on welding seam and, at the same time, the transformation of side-batten ferrite is resisted while the pin-ferrite s tructure is promoted. The improvement of the toughness of the welding seam is du e to the purifying action of rare earth elements as well as their refining effec t on the structure. However, the toughness of the welding seam can decrease whe n the amount of light rare earth elements are added excessively because the crys tal grains become coarser, porosities appear and the inclusions increase as well . The experimental results show that the suitable amount of light rare earth ele ment additions is about 2%.

On Generating Expected Kinetostatic Nonlinear Stiffness Characteristics by the Kinematic Limb-Singularity of a Crank-Slider Linkage with Springs

Being di erent from avoidance of singularity of closed-loop linkages, this paper employs the kinematic singularity to construct compliant mechanisms with expected nonlinear sti ness characteristics to enrich the methods of compliant mechanisms synthesis. The theory for generating kinetostatic nonlinear sti ness characteristic by the kinematic limb-singularity of a crank-slider linkage is developed. Based on the principle of virtual work, the kinetostatic model of the crank-linkage with springs is established. The influences of spring sti ness on the toque-position angle relation are analyzed. It indicates that corresponding spring sti ness may generate one of four types of nonlinear sti ness characteristics including the bi-stable, local negative-sti ness, zero-sti ness or positive-sti ness when the mechanism works around the kinematic limb-singularity position. Thus the compliant mechanism with an expected sti ness characteristic can be constructed by employing the pseudo rigid-body model of the mechanism whose joints or links are replaced by corresponding flexures. Finally, a tri-symmetrical constant-torque compliant mechanism is fabricated,where the curve of torque-position angle is obtained by an experimental testing. The measurement indicates that the compliant mechanism can generate a nearly constant-torque zone.

基于NESS模型构建现代建筑产业集群评价体系

当前,我国装配式建筑市场发展迅速,在部分城市已经形成了建筑产业集群。现代建筑产业集群的打造,不仅仅是与新常态下建筑产业的可持续发展需求相适应,同时还将有助于集群内的企业之间的交互与融合发展,将更加有助于竞争优势的发挥。然而,当前对于建筑产业集群这种新模式的评价体系还不完善,不利于产业集群的发展。为了更好地推动现代建筑产业集群发展,了解其形成机理以及集群中核心主体之间的相互影响,本文根据产业组织理论定义现代建筑产业集群的概念和内涵,明确现代建筑产业链的组成,并基于产业链的主体界定了现代建筑产业集群主体间的连接关系,利用NESS模型构建产业集群的评价体系,为现代建筑产业集群的发展提供理论支撑。

The Semantical Completeness of the Extensions L_n~* to the System L^(* *)

The terminology of "fuzzy logic" has been formed and employed with different meanings bya large number of researchers soon after Zadeh published his initiate paper (see [1]), butperhaps the most serious work on fuzzy logic is the Pavelka’s series papers (see [2]) whichprovided a systematical theory of fuzzy logic mathematically and profoundly, and hence

Equivalence of three kinds of well-posed-ness of discontinuous Riemann-Hilbert problem for elliptic complex equation in multiply connected domains

In this article, we first introduce the general linear elliptic complex equation of first order with certain conditions, and then propose discontinuous Riemann-Hilbert problem and some kinds of modified well-posed-ness for the complex equation. Then we verify the equivalence of three kinds of well-posed-ness. The discontinuous boundary value problem possesses many applications in mechanics and physics etc.

Examining the Present and Future Integrated Role of Artificial Intelligence in the Business: A Survey Study on Corporate Sector

In the fast-moving world, it is noticed that every industry is developing gradually, but recently it is identified that the use of AI has become the talk of own. Therefore, this study is focused on gathering data regarding the AI on how it has transformed the entire world’s corporate sector. The essential application AI in the business world helps the business to perform better in the corporate sector. In this paper, the critical role of artificial intelligence is to grow business in different sectors and also address its ethical and unethical issues. The paper has all the initial background and comprehensive literature regarding AI and machine learning. It is discovered how the technological world has been striving to take their business on to new heights, which requires updated technological changes in internal business activities. Companies can now effortlessly interact with their customers in making their application accessible for the end-users through implementing AI and machine learning. Companies are getting higher profitability and enhancing their performance and achieving economic advantages by integrated AI. Moreover, their technological developments will take human jobs in the future, so, it is suggested that humans should work on their skills and competencies so that they can deal with unemployment.

Effect of Eccentric Shear Stiffness of Walls on Structural Response of RC Frame Buildings

Current research study consists of determining the optimum location of the shear wall to get the maximum structural efficiency of a reinforced concrete frame building. It consists of a detailed analysis and design review of a seven-story reinforced concrete building to understand the effect of shear wall location on the response of reinforced concrete structures when subjected to different earthquake forces. Three trail locations of shear walls are selected and their performance is monitored in terms of structural response under different lateral loads. Required objectives are achieved by obtaining design and construction drawings of an existing reinforced concrete structure and modeling it on Finite Element Method (FEM) based computer software. The structure is redesigned and discussed with four different configurations (one without shear wall and three with shear walls). Main framing components (Beams, Columns and Shear walls) of the superstructure are designed using SAP 2000 V. 19.0 whereas substructure (foundation) of RC building was?designed using SAFE. American Concrete Institute (ACI) design specifications were used to calculate the cracked section stiffness or non-linear geometrical properties of the cracked section. Uniform Building Code (UBC-97) procedures were adopted to calculate the lateral earthquake loading on the structures. Structural response of the building was monitored at each story level for each earthquake force zone described by the UBC-97. The earthquake lateral forces were considered in both X and Y direction of the building. Each configuration of shear wall is carefully analyzed and effect of its location is calibrated by the displacement response of the structure. Eccentricity to the lateral stiffness of the building is imparted by changing the location of shear walls. Results of the study have shown that the location of shear wall significantly affects the lateral response of the structure under earthquake forces. It also motivates to carefully decide the center of lateral stiffness of building prior to deciding the location of shear walls.

深圳-NESS:空间衍异——记一次探索深圳性的策展实验

从地缘政治对深圳特区四十年城市空间衍变的结果进行理论研究和实验性重构,理论研究层面:从深圳城市空间形态演变的表象出发,抽离其底层空间生产的表征性特点,构建空间再生产的实践性实验来映射深圳城市发展的未来性。策展实验层面:以全球化策展的缘起阐述对深圳性的理解,通过分析深圳5个具体典型空间实例,探索其集成空间呈现的深圳特征—构建5个实验性场景—感知未来深圳空间再生的可能性。

基于区位商和NESS模型的新能源产业集群水平识别与评价——以浙江省为例

综合运用了区位商法、NESS模型、层次分析法和模糊数学综合评价法,识别和评价浙江省新能源产业集群水平。基于区位商法,2006—2010年浙江省新能源产业集聚水平居全国第一。温州、台州、杭州和宁波四个地区的新能源产业集聚程度最高。基于NESS模型,从新能源集聚、经济网络、社会网络和服务体系四个方面来看,浙江省新能源产业集群仍处于初级阶段。基于层次分析法和模糊数学综合评价法,有9.02%的专家认为浙江省新能源产业集群已经成熟,33.53%的专家认为浙江省新能源产业集群属于成长型,45.88%的专家认为浙江省新能源产业集群属于起步阶段,还有11.57%的专家认为浙江省新能源产业集群尚未形成或远未形成。综合三种识别和评价方法,认为浙江省新能源产业集群处于起步阶段。

Y2O3增强TC4合金焊激光熔覆仿真及微观组织性能研究

TC4(Ti-6Al-4V)钛合金因其低密度、高比强度和良好的加工性能,在航空航天、航海石油和国防等领域得到了广泛应用。然而,其硬度低、耐磨性差,限制了其在摩擦工况下的使用。基于涂层与TC4基材的相容性及基体对生成相的润湿性原理,在TC4表面制备了Ti基稀土激光熔覆层,研究了Y2O3对涂层显微硬度和耐磨性能的影响。通过COMSOL软件模拟单道和多道TC4粉末熔覆动态过程,结合试验研究温度变化与熔覆层厚度,阐明了熔覆机理并验证了模型的正确性。对熔覆层的组织结构和物相组成进行了详细分析,利用显微维氏硬度计测量熔覆层硬度,结果表明,Y2O3增加显著减少了气泡和裂纹数量,促进了组织细化。为TC4表面激光熔覆涂层的微观组织调控、成形质量提供了试验和理论依据。

不考虑几何刚度的桁架结构非线性分析方法

一般进行结构非线性分析时,需特别考虑在大变形情况下结构刚度的变化,但切线刚度或几何刚度的推导过程较为复杂,众多研究关注于结构单元刚度矩阵的推导而忽略了非线性分析的整体过程。基于增量迭代非线性分析的力学机制,在保证桁架单元节点恢复力求解精度的情况下,仅考虑弹性或弹塑性刚度而不考虑桁架结构的几何刚度也可以分析桁架结构的非线性行为。通过与常规考虑几何刚度的情况进行对比分析,计算结果十分吻合,只是增加了少量的计算时间与迭代次数。此不考虑几何刚度的桁架结构非线性计算过程物理意义清晰,可推广至其他类型的结构。

滋阴除湿汤联合西替利嗪治疗老年糖尿病性皮肤瘙痒症阴虚湿恋证的临床效果分析

目的:探究滋阴除湿汤联合西替利嗪治疗老年糖尿病性皮肤瘙痒症阴虚湿恋证的临床效果。方法:选取2022年1月—2023年4月于北京中医医院内蒙古医院接受治疗的糖尿病性老年皮肤瘙痒症阴虚湿恋证患者60例作为研究对象,随机分为两组,各30例。两组均给予糖尿病对症治疗,对照组在此基础上给予盐酸西替利嗪片治疗,观察组在对照组基础上给予滋阴除湿汤治疗。对比两组治疗效果。结果:观察组治疗总有效率比对照组高(P=0.024)。治疗后,两组瘙痒程度、瘙痒部位、瘙痒持续时间及瘙痒对睡眠的影响评分均降低,且观察组比对照组低(P<0.05)。治疗后,两组空腹血糖、餐后2 h血糖水平均低于治疗前,但两组组间比较,无统计学差异(P>0.05);两组糖化血红蛋白水平均低于治疗前,且观察组低于对照组(P<0.05)。结论:滋阴除湿汤联合西替利嗪治疗老年糖尿病性皮肤瘙痒症阴虚湿恋证的临床效果较好,能够减轻患者瘙痒程度,降低糖化血红蛋白水平,且安全性较高。

ON THE BOUNDEDNESS OF A CLASS OF NONLINEAR DYNAMIC EQUATIONS OF THE THIRD ORDER

In this paper, a modified nonlinear dynamic inequality on time scales is used to study the boundedness of a class of nonlinear third-order dynamic equations on time scales. These theorems contain as special cases results for dynamic differential equations, difference equations and q-difference equations.

Simulation and Validation of the Aerosol Optical Thickness over China in 2006

The Model of Atmospheric Transport and Chemistry （MATCH） developed by the US National Center for Atmospheric Research （NCAR） was used to calculate the aerosol optical thickness （AOT） over China in 2006, with emission source data of the Intercontinental Chemical Transport Experiment Phase B （INTEX-B） and NCEP/NCAR reanalysis data as inputs. The simulation results of AOT were then validated with obser- vational data from the Moderate Resolution Imaging Spectroradiometer （MODIS）, Chinese Sun Hazemeter Network （CSHNET）, Aerosol Robotics Network （AERONET）, and China Aerosol Remote Sensing Network （CARSNET） at more than 30 stations over China. The comparison results indicated that the high values of AOT in the areas such as the Sichuan basin and East and South China and the low values of AOT over the Tibetan Plateau and Northwest and Northeast China were reasonably simulated by the MATCH. This model tended to underestimate the AOT values in high-aerosol-loading areas but overestimate the AOT val- ues in less polluted areas because there are still large uncertainties in the expression of emission sources, the description of the optical properties of aerosols, the treatment of cloud and precipitation, and the selection of grid resolution. The modeling results were consistent with the CSHNET, CARSNET, AERONET, and MODIS data in most parts of China, and the correlation coefficient of the monthly mean AOT between the model and the observation was 0.79 with CSHNET data at 23 stations, 0.51 with MODIS data, and 0.88 with data at 3 CARSNET stations and 2 other stations. All of them passed the significance test with c 〈 0.0001. The results demonstrated that the MATCH has the ability to simulate the characteristics of the AOT distribution and its seasonal variation over China.

Loch Ness Monster Caught on Film

尼斯湖是苏格兰境内的一个旅游胜地,近日传说中的水怪在那里再度现身,并有目击者拍下了视频资料。不过尼斯湖水怪是否存在一直存有争议,此次视频也毕竟没有拍到它的庐山真面目,这个世界之谜还是一如既往的神秘。

考虑互补效应的城市群多模式客运网络鲁棒性

为了分析城市群客运网络对突发事件的应对能力,从多种交通模式互补视角,基于复杂网络理论构建城市群多模式客运网络模型,应用引力模型建立节点失效后网络性能计算的规则,对城市群多模式客运网络的鲁棒性进行测度.引入基于鲁棒性的动态互补强度指标,对客运网络间的互补效应(CE)进行量化.对是否考虑CE时的鲁棒性进行对比,分析CE对鲁棒性的提升程度.以关中平原城市群为例进行实例研究,结果表明,在城市群多模式客运网络中,普铁网应对突发事件时的鲁棒性最强,公路网最弱.无论在何种攻击策略下,考虑CE时,城市群多模式客运网络的鲁棒性均有明显的提升,高铁网、普铁网和公路网的敏感度分别下降了19.1%、29.3%和22.0%.

数字化水平对企业可持续绩效的影响研究——创新类型的中介作用和环境竞争性的调节作用

基于可持续发展和技术可供性理论,以2015-2021年中国沪深A股上市的制造业企业为研究样本,采用文本挖掘方法衡量企业数字化水平,实证检验数字化水平对企业可持续绩效的影响,探究技术创新和商业模式创新的中介作用,同时考虑环境竞争性对数字化水平与企业创新(技术创新和商业模式创新)的调节作用。实证结果表明:(1)数字化水平显著促进制造业企业可持续绩效;(2)技术创新和商业模式创新两者都在数字化水平与制造业企业可持续绩效之间发挥了部分中介作用;(3)环境竞争性在数字化水平与技术创新关系中存在显著负向调节作用,而在数字化水平与商业模式创新关系中的调节作用不显著。

断点回归方法及应用实现

目的完整、系统介绍断点回归设计(RDD)原理及统计方法,为其在公共卫生领域应用提供参考。方法在介绍断点回归设计原理基础上,用室内甲醛干预的实例演示了利用Stata软件实现断点回归统计方法的过程,介绍和比较属于参数法的多项式回归和属于非参数法的局部线性回归的分析方法和结果。结果RDD是一种准实验设计,对研究对象没有随机分组,而是选择一个与干预措施有关的变量,根据该变量的取值选择切点划分干预组和对照组。RDD在内部有效性方面优于其他准实验设计,但外部有效性受到一定限制。基于观察性资料的RDD不仅可控制可观测的混杂因素,还可控制无法观测的混杂因素,也更符合伦理道德。在本文实例中,多项式回归和局部线性回归两种分析方法的结果基本一致。结论RDD在公共卫生领域的真实世界研究中有广阔的应用前景,为科学评估干预政策和提供高质量决策依据提供新的思路和方法。