TIME-HARMONIC DYNAMIC GREEN'S FUNCTIONS FOR ONE-DIMENSIONAL HEXAGONAL QUASICRYSTALS

Quasicrystals have additional phason degrees of freedom not found in conventional crystals. In this paper, we present an exact solution for time-harmonic dynamic Green＇s function of one-dimensional hexagonal quasicrystals with the Laue classes 6/mh and 6/mhmm. Through the introduction of two new functions φ and ψ, the original problem is reduced to the determination of Green＇s functions for two independent Helmholtz equations. The explicit expressions of displacement and stress fields are presented and their asymptotic behaviors are discussed. The static Green＇s function can be obtained by letting the circular frequency approach zero.

GREEN FUNCTION ON TWO-PHASE SATURATED MEDIUM BY CONCENTRATED FORCE IN TWO-DIMENSIONAL DISPLACEMENT FIELD

The Green function on two-phase saturated medium by concentrated force has a broad and important use In seismology, seismic engineering, soil mechanics, geophysics, dynamic foundation theory and so on. According to the Green function on two-phase saturated medium by concentrated force in three-dimentional displacement field obtained by Ding Bo-yang et al., it gives out the Green function in two-dimensional displacement field by infinite integral method along x(3)-direction derived by De Hoop and Manolis. The method adopted in the thesis is simpler. The result will be simplified to the boundary element method of dynamic problem.

Green Measurements for Software Product Based on Sustainability Dimensions

Software is a central component in the modern world and vastly affects the environment’s sustainability.The demand for energy and resource require-ments is rising when producing hardware and software units.Literature study reveals that many studies focused on green hardware;however,limited efforts were made in the greenness of software products.Green software products are necessary to solve the issues and problems related to the long-term use of soft-ware,especially from a sustainability perspective.Without a proper mechanism for measuring the greenness of a particular software product executed in a specific environment,the mentioned benefits will not be attained.Currently,there are not enough works to address this problem,and the green status of software products is uncertain and unsure.This paper aims to identify the green measurements based on sustainable dimensions in a software product.The second objective is to reveal the relationships between the elements and measurements through empirical study.The study is conducted in two phases.Thefirst phase is the theoretical phase,where the main components,measurements and practices that influence the sustainability of a software product are identified.The second phase is the empirical study that involved 103 respondents in Malaysia investigating current practices of green software in the industrial environment and further identifying the main sustainability dimensions and measurements and their impact on achiev-ing green software products.This study has revealed seven green measurements of software product:Productivity,Usability,Cost Reduction,Employee Support,Energy Efficiency,Resource Efficiency and Tool Support.The relationships are statistically significant,with a significance level of less than 0.01(p=0.000).Thus,the hypothesised relationships were all accepted.The contributions of this study revolve around the research perspectives of the measurements to attain a green software product.

A simplified two-dimensional boundary element method with arbitrary uniform mean flow

To reduce computational costs, an improved form of the frequency domain boundary element method（BEM） is proposed for two-dimensional radiation and propagation acoustic problems in a subsonic uniform flow with arbitrary orientation. The boundary integral equation（BIE） representation solves the two-dimensional convected Helmholtz equation（CHE） and its fundamental solution, which must satisfy a new Sommerfeld radiation condition（SRC） in the physical space. In order to facilitate conventional formulations, the variables of the advanced form are expressed only in terms of the acoustic pressure as well as its normal and tangential derivatives, and their multiplication operators are based on the convected Green＇s kernel and its modified derivative. The proposed approach significantly reduces the CPU times of classical computational codes for modeling acoustic domains with arbitrary mean flow. It is validated by a comparison with the analytical solutions for the sound radiation problems of monopole,dipole and quadrupole sources in the presence of a subsonic uniform flow with arbitrary orientation.

采用Green函数法求解二维固结微分方程

以Terzaghi一维固结理论为基础,采用Green函数法对二维固结微分方程进行求解,得到了不同边界条件及地基应力条件下的二维固结微分方程的解析解,给出了计算表,进一步推导了线性加载下的解答。以一均质地基为例,将计算结果与一维解答、前人所得数值结果进行对比,验证了该方法的准确性与可靠性。研究结果表明:进行工程实际研究时应重点关注荷载中心点下的平均固结度,荷载宽度与地基宽度越接近,荷载中心点下的平均固结度与一维结果越接近;而当地基宽度远大于荷载宽度和软土厚度时,使用一维固结理论计算误差较小,工程设计中是可靠的。该方法解答考虑更多工程情况,更快捷方便,便于工程人员使用,可应用于工程计算。

Solution of two-dimensional scattering problem in piezoelectric/piezomagnetic media using a polarization method

Using a polarization method, the scattering problem for a two-dimensional inclusion embedded in infinite piezoelectric/piezomagnetic matrices is investigated. To achieve the purpose, the polarization method for a two-dimensional piezoelectric/piezomagnetic ＂comparison body＂ is formulated. For simple harmonic motion, kernel of the polarization method reduces to a 2-D time-harmonic Green＇s function, which is obtained using the Radon transform. The expression is further simplified under conditions of low frequency of the incident wave and small diameter of the inclusion. Some analytical expressions are obtained. The analytical solutions for generalized piezoelectric/piezomagnetic anisotropic composites are given followed by simplified results for piezoelectric composites. Based on the latter results, two numerical results are provided for an elliptical cylindrical inclusion in a PZT-5H-matrix, showing the effect of different factors including size, shape, material properties, and piezoelectricity on the scattering cross-section.

Exact analytical solution to three-dimensional phase change heat transfer problems in biological tissues subject to freezing

Analytically solving a three-dimensional （3-D） bioheat transfer problem with phase change during a freezing process is extremely difficult but theoretically important. The moving heat source model and the Green function method are introduced to deal with the cryopreservation process of in vitro biomaterials. Exact solutions for the 3-D temperature transients of tissues under various boundary conditions, such as totally convective cooling, totally fixed temperature cooling and a hybrid between them on tissue surfaces, are obtained. Furthermore, the cryosurgical process in living tissues subject to freezing by a single or multiple cryoprobes is also analytically solved. A closed-form analytical solution to the bioheat phase change process is derived by considering contributions from blood perfusion heat transfer, metabolic heat generation, and heat sink of a cryoprobe. The present method is expected to have significant value for analytically solving complex bioheat transfer problems with phase change.

船舶有航速时三维时域格林函数计算方法研究

船舶工业CAE软件势流求解器的开发对势流计算方法的可靠性提出要求,本文针对船舶有航速时深水三维时域格林函数计算方法开展研究。首先引入三维时域自由面格林函数,其瞬时项的求解采用Hess&Smith方法,自由面记忆项的求解采用美国密歇根大学Beck团队的方法。其次,分区域推导出三维时域自由面格林函数记忆项及其导数的编程所用的数学展开表达式。然后,采用间接法模型求解分布源强和速度势,并采用压力直接积分法求出时域辐射力。最后,针对Wigley I船型开展了辐射力计算,并与公开的试验及计算结果进行对比,验证本文方法的可靠性。

含铁纳米纤维电极去除水中孔雀石绿

作为一种典型的三苯甲烷类染料,孔雀石绿具有降解难度大、对生态环境和人类危害大等特点,因此水中孔雀石绿的治理问题不容忽视。本工作借助静电纺丝技术和液相还原法,将纳米铁颗粒物负载于高度蓬松的PVA纳米纤维,制备高性能的含铁纳米纤维,并利用其作为第三维电极构建三维电极反应体系,考察三维电极体系中孔雀石绿的去除行为。结果表明,未接通电源时含铁纳米纤维对水中孔雀石绿具有良好的吸附效果,吸附行为符合准二级动力学模型;在三维电极体系中,含铁纳米纤维先借助吸附作用对水中孔雀石绿进行富集浓缩,然后通过电解作用同时实现孔雀石绿的降解和含铁纳米纤维活性位点的再生。在预吸附-电解40 min后,水中孔雀石绿的去除率超过了95%,且反应体系呈现出较强的pH值耐受性。

三维时域自由面格林函数法的时域绕射力计算研究

船舶工业CAE软件势流求解器的开发对势流计算方法的可靠性提出要求,本文针对三维时域面元法开展绕射力计算研究。首先引入三维时域自由面格林函数,其瞬时项的求解采用Hess&Smith方法,记忆项的求解采用Beck团队的方法;其次,推导出全浪向绕射力脉冲函数法编程所用的数学表达式;然后,采用分布源模型求解源强和速度势,并采用压力直接积分法求出时域绕射力;最后,针对Wigley I船型开展绕射力和FK力计算,并与公开的试验和计算结果进行对比,验证本文方法的可靠性。本文方法和代码可用于船舶工业CAE软件势流求解器和波浪中船舶非线性失稳运动预报。

城市高架桥下新自然生境重建模式及维持策略——以上海市为例

【目的】城市高架桥下低光照、高污染、强干旱的特殊生境,严重影响了植物健康生长。构建高架桥“植物筛选—生境营造—可持续运维”的立体绿化体系,重建城市高架桥下新自然生境,可以有效改善城市高架桥下生境与人居环境,提高城市生物多样性。【方法】基于生境相似性原理,运用适应性、观赏性、功能性3层过滤模式筛选适生植物;制定“建筑-设施-介质”一体化策略;提出实现高架桥下立体绿化自维持运营的创新模式。【结果】筛选出了27种适宜种植于高架桥下特殊生境的抗性强的适生植物,丰富了高架桥下特殊生境的植物多样性,使植物单次更换周期延长至5年以上;研发出集适生植物、轻型栽培介质、叠垒式种植容器、浇灌系统、雨水收集净化设施于一体的新型立体绿化模块,支撑植物长期保持良好的生长状态,同时实现了雨水资源化利用、污染源头控制和城市雨水消纳等多重目标;在景观形式上,将平面绿化拓展到立体绿化,复合利用大量已建成的城市灰色空间来增绿、填绿,预期可为上海市增加0.3 m^(2)的人均绿化面积;创新性地提出以“绿”促“商”、以“商”养“管”的运维模式,建立了上海虹梅高架桥下立体绿化新模式示范段。【结论】通过研发城市典型的低光照区域立体绿化技术,集成了新型立体绿化模块,将覆盖面广、连通性强的城市狭长污染线——城市高架桥下空间转型为生命景观线、生物多样性廊道,为城市可持续发展提供重要的生态、经济效益。

二维线性化Navier-Stokes-Poisson方程解的逐点估计

本文研究了二维空间线性化的等熵可压缩Navier-Stokes-Poisson方程柯西问题.通过把方程组转变成关于单个函数的方程,求解出各个函数,得到方程组的格林函数.利用对格林函数的详细分析,获得了方程组解的逐点估计.结果显示方程组中电流密度以热核的速度衰减,动量密度衰减慢得多,且其L2范数不衰减.

立体绿化在创建国家园林城市的构建模式研究——以达州市中心城区为例

为推动绿色发展,建设美丽达州,达州市启动创建国家森林城市工作。两年之后,再次提出中心城区创建国家园林城市、国家森林城市的目标,围绕达州中心城区创建国家园林城市,构建城市立体绿化体系策略研究。上海、深圳厦门等沿海城市的立体绿化起步早,形成了较为完整的支撑体系,上海经过世博会,使之立体绿化走在了世界的前列,立体绿化属低碳绿化,是城市建设节能、低碳、生态的好办法,是花钱少、见效快、效果好,受欢迎的未来城市建设的发展之路,符合资源节约型、环境友好型城市建设的发展方向。将立体绿化与传统文化元素融合,提出了具有实践参考的设计原则与设计方法,使现代城市绿化充分发挥自身文化价值,赋予城市绿化的文化功能,提升达州城市形象,增强文化认同感,为城市绿色发展方式的转变,城市可持续发展建设实施提供一定的理论支撑。构建城市景观人文与自然相协调的原则,突出城市特色,既显山露水,又延续历史文脉。项目设计实施有助于改变当前居民小区景观同质化、形式化的设计问题,同时也赋予城市空间立体绿化的文化表达功能,提升达州的城市品牌形象,为城市增添更丰富的绿色空间和文化交流场所。

基于三维激光点云数据的校园绿地乔木三维绿量对比研究——以广西生态工程职业技术学院为例

树冠是指树干以上连同其生枝叶的部分,其体积的大小是估算树木三维绿量的重要参数。校园绿地中乔木树冠形态各异,结构复杂,树木树冠体积的准确、自动、无损测量是校园绿地调查中的一个重要研究项目。随机抽取广西生态工程职业技术学院内5个树种共计25棵乔木的三维激光点云数据与树木三维绿量冠幅-冠高公式法进行了对比研究。以三维激光扫描仪获取的三维激光点云数据基于不规则三角网法计算乔木树冠体积。计算结果对比表明:测量值与参考值的均方根误差RMSE为2.913、绝对误差最大值为7.22 m3,最小值为0.17 m3;相对误差最大值为11.06%,最小值为0.12%;平均绝对误差为2.20 m3,平均相对误差为3.13%,该算法不用考虑树冠的形状,减少了人为判别导致的差异。因此,以三维激光扫描仪获取点云数据,运用不规则三角网法自动提取校园绿地乔木树冠体积快捷、有效、可推广。

绿色低碳导向下的在地共生——当代大学校园更新设计策略探索

本文将“校城割裂”视作大学校园绿色低碳发展的阻碍,提出“在地共生”理念,推进校城开放融合,从而以高效的能量组织降低绿色低碳发展的成本,优化建筑循环代谢模式,提升建筑环境性能。此外,本文在成因分析的基础上引入整体思维、系统思维和发展思维的理论框架,推导出“多维编织”的设计策略,以期完成复合的在地共生目标,并通过3座大学校园的实践案例来印证以上观点。

集中力作用下两相饱和介质二维位移场Green函数

由于工程场地的对称性,集中力作用下的位移场Green函数在土力学、地震工程学和动力基础方面的应用需以二维模型出现· 在理论推导上Green函数的二维模型要比三维模型复杂· 根据丁伯阳等人已得到的三维位移场中集中力作用下两相饱和介质位移场Green函数,采用DeHoop与Manolis给出的沿x3方向在无穷域积分方法,得到了集中力作用下两相饱和介质二维位移场Green函数· 相比已有的工作,所得结果不仅简单。

三维可视化吲哚菁绿荧光示踪对肝细胞癌解剖性肝切除术安全性及预后的影响

目的探究三维可视化吲哚菁绿(ICG)荧光示踪对肝细胞癌(HCC)解剖性肝切除术安全性及预后的影响。方法回顾性分析2019年4月至2021年4月孝感市中心医院收治的55例HCC患者的临床资料,根据手术方式分为对照组(n=29)与实验组(n=26)。对照组行常规解剖性肝切除术,实验组行三维可视化ICG荧光示踪技术联合解剖性肝切除术。比较两组手术情况、肝功能指标、预后情况及并发症发生情况。结果两组术中输血量、术后住院时间比较差异无统计学意义;实验组术中出血量少于对照组,阻断时间、手术总时间均短于对照组,差异有统计学意义(P<0.05)。治疗前,两组丙氨酸氨基转移酶(ALT)、总胆红素(TBiL)、谷草转氨酶(AST)水平比较差异无统计学意义;治疗后,两组ALT、TBiL、AST水平均低于治疗前,差异有统计学意义(P<0.05),但组间比较差异无统计学意义。实验组预后良好率高于对照组,差异有统计学意义(P<0.05)。实验组并发症发生率为34.61%,低于对照组的65.51%,差异有统计学意义(P<0.05)。结论与常规解剖性肝切除术相比,采用三维可视化ICG荧光示踪技术可准确进行病灶识别与可视化,显著改善患者预后,降低并发症发生率。

三维可视化、荧光影像联合超声技术在外科治疗重度肝硬化相关性小肝癌定位中的应用效果

目的:分析联合三维可视化技术、吲哚菁绿荧光影像和超声技术在合并重度肝硬化小肝癌精准定位中的应用效果。方法:回顾性分析2019年01月至2022年12月我院普通外科行开腹和腹腔镜手术治疗合并重度肝硬化的63例小肝癌患者资料。在术中超声辅助的基础上,根据是否联用三维可视化、荧光影像技术分为观察组(n=33)和对照组(n=30)。比较两组患者的手术治疗、实验室检查指标和术后并发症情况。结果:观察组患者手术时间明显较对照组短,且术中出血量也明显少于对照组。术后病灶残留也较对照组少。两组术后3天ALT、AST和TBil差异均有统计学意义(P<0.05),观察组的ALT、AST和TBil水平显著低于对照组。结论:对于合并重度肝硬化的小肝癌行开腹或腹腔镜手术时联合三维可视化技术、吲哚菁绿荧光影像技术、超声技术有助于定位肝癌,提高治疗效果。

改进NSGA-III求解高维多目标绿色柔性作业车间调度问题

为解决NSGA-III在求解上述模型存在初始解质量差与局部搜索效率低的问题,提出一种改进的NSGA-III(NSGA-III-TV)。基于MSOS编码,分别对OS和MS染色体采取不同混合初始化策略以提高初始解质量;基于关键路径,采用改进N6邻域结构进行邻域搜索,有效缩短完工时间并降低搜索盲目性,同时采用3种有效变异算子扩大算法搜索空间,提高后期收敛能力。结果表明:NSGA-III-TV在求解高维多目标柔性作业车间调度问题上具有较好的性能以及实用性,为企业生产制造车间的智能绿色转型升级提供了有力支持。