塔里木沙漠公路防护林土壤微生物生物量与土壤环境因子的关系

为探讨极端干旱区风沙土土壤微生物与土壤环境因子的作用规律,采用相关分析法研究了塔里木沙漠公路防护林地土壤微生物生物量与理化因子和酶活性的关系.结果表明:土壤容重和粒径减小(R0.85)时,防护林地中土壤微生物数量和生物量有增大趋势,由容重与微生物量的相关性主导;土壤养分含量与土壤微生物数量和生物量呈正相关,主要由速效养分和放线菌、微生物生物量C、P的相关性所致;土壤酶活性与土壤微生物数量和生物量的相关性差异较大,R在0.51～0.91,主要取决于蔗糖酶、磷酸酶与放线菌、微生物量C的相关;土壤盐分增加不利于土壤微生物生物量的积累(R0.63).实践中应为干旱区林地土壤微生物营造良好的土体,促进土壤物质循环

Buckling theory and stretchability of structures with finite prebuckling deformation

&nbsp; &nbsp; 柔性电子器件在健康医疗、智能工业、航空航天等领域有着广泛的应用前景。力学结构设计是无机柔性电子器件实现可变形能力的关键，薄膜屈曲互联导线被大量采用来实现器件的可拉伸性。研究发现，厚截面互联导线在部分工况下可以提供更好的力学可拉伸性，且同时具有更优异的电学和热学性能。与薄膜屈曲互联导线不同，厚截面互联导线在屈曲前会发生较大的初始变形，所以我们称这类结构为&ldquo;有限初始变形结构&rdquo;。本论文系统研究有限初始变形结构的屈曲理论和可拉伸性优化设计，具体如下： &nbsp; &nbsp; 细长欧拉压杆等结构在屈曲前的变形通常很小，所以传统的屈曲理论和数值方法中通常忽略了屈曲前变形的影响，只考虑了屈曲前应力的作用。而我们发现厚截蛇形面互联导线在屈曲前会发生很大的初始变形，这对屈曲临界载荷的确定至关重要。虽然近一百年来屈曲理论已经取得了很大的进展，但目前还没有考虑屈曲前变形的屈曲理论，为此有必要建立考虑屈曲前变形影响的有限初始变形屈曲理论。本文通过拉伸实验测得了不同厚度蛇形互联导线的屈曲临界位移载荷，澄清了传统屈曲理论和数值方法由于忽略屈曲前变形的影响而引起较大误差（梁截面厚宽比为0.6时，传统屈曲理论会产生超过50%的误差）的原因。系统建立了考虑屈曲前变形的三维空间直梁的有限初始变形屈曲理论，用以分析梁在弯曲、扭转和拉伸/压缩耦合作用下的屈曲行为。求解了梁的三点弯侧向屈曲、纯弯侧向屈曲和欧拉屈曲三个经典问题。结果显示有限初始变形屈曲理论给出了更为精确的结果，而传统屈曲理论和数值方法会产生较大的误差（梁截面厚宽比为0.8时，三点弯侧向屈曲临界力结果误差达70%）。 &nbsp; &nbsp; 弹性基体被广泛应用于柔性电子器件，其在某些工况下同样会产生很大的屈曲前变形。本文系统建立了考虑屈曲前变形影响的块体结构的有限初始变形屈曲理论，求解了半无限大弹性平面屈曲和弹性矩形块体结构屈曲两个经典问题。与分步加载卸载有限元方法得出的精确解相比，有限初始变形屈曲理论给出了准确的结果，而传统屈曲理论和数值方法则会产生较大的误差（半无限大弹性平面屈曲临界力结果误差超过70%）。梁和块体结构的有限初始变形屈曲理论的建立对柔性电子器件可拉伸结构的力学分析、优化设计以及实际应用具有重要的意义。 &nbsp; &nbsp; 本文将预应变策略应用于厚截面蛇形互联导线结构设计，系统研究了厚截面蛇形互联导线在基体释放预应变阶段和基体拉伸阶段的有限变形问题。结果表明，理论分析模型和有限元所得结果一致，证明了将预应变策略应用于厚截面蛇形互联导线可进一步提升整体结构的可拉伸性；较大的预应变、较长的直线段和较小的弧半径设计可以增强厚截面蛇形互联导线的可拉伸性能；但在基体释放预应变后，较大的预应变会导致厚截面蛇形互联导线产生较大的应变。因此，需选择合适的预应变值(厚截面蛇形互联导线在基体释放预应变后不发生破坏)以达到最优的可拉伸性能。</p

一种三层柔性电池结构及制备方法

本发明公开了一种三层柔性电池结构，它包括柔性基底(1)、岛桥结构(2)、电池(3)。本发明将柔性基底之上的电池和导线设计为三层结构，中间一层为紧密排列的电池阵列，电池上下两侧为导电小圆柱以及使它们并联的铜导线，它们分别引出电池的正极与负极，每个小圆柱都对应与其共中心的正方形电池部分，电池之间紧密排列覆盖整个基底，整个结构具有很高的延展性，同时实现了电池覆盖率的最大化，极大地提升了电池单位面积容量

Buckling of Bulk Structures With Finite Prebuckling Deformation

The prebuckling deformation of structures is neglected in most of the conventional buckling theory (CBT) and numerical method (CNM), because it is usually very small in conventional concepts. In the preceding paper (Su et al., 2019), we found a class of structures from the emerging field of stretchable electronics, of which the prebuckling deformation became large and essential for determining the critical buckling load, and developed a systematic buckling theory for 3D beams considering the effects of finite prebuckling deformation (FPD). For bulk structures that appear vastly in the advanced structures, a few buckling theories consider the effects of the prebuckling deformation in constitutive equations by energy method, which are significantly important but not straightforward and universal enough. In this paper, a systematic and straightforward theory for the FPD buckling of bulk structures is developed with the use of two constitutive models. The variables for the prebuckling deformation serve as the coefficients of the incremental displacements, deformation components, and stress in the buckling analysis. Four methods, including the CBT, CNM, DLU (disturbing-loading-unloading method) method and FPD buckling theory, are applied to the classic problems, including buckling of an elastic semi-plane solid and buckling of an elastic rectangular solid, respectively. Compared with the accurate buckling load from the DLU method, the FPD buckling theory is able to give a good prediction, while the CBT and CNM may yield unacceptable results (with 70% error for the buckling of an elastic semi-plane solid)

Mechanics of nonbuckling interconnects with prestrain for stretchable electronics*

The performance of the flexibility and stretchability of flexible electronics depends on the mechanical structure design, for which a great progress has been made in past years. The use of prestrain in the substrate, causing the compression of the transferred interconnects, can provide high elastic stretchability. Recently, the nonbuckling interconnects have been designed, where thick bar replaces thin ribbon layout to yield scissor-like in-plane deformation instead of in- or out-of-plane buckling modes. The nonbuckling interconnect design achieves significantly enhanced stretchability. However, combined use of prestrain and nonbuckling interconnects has not been explored. This paper aims to study the mechanical behavior of nonbuckling interconnects bonded to the prestrained substrate analytically and numerically. It is found that larger prestrain, longer straight segment, and smaller arc radius yield smaller strain in the interconnects. On the other hand, larger prestrain can also cause larger strain in the interconnects after releasing the prestrain. Therefore, the optimization of the prestrain needs to be found to achieve favorable stretchability

“有限初始变形”屈曲实验和理论研究（英文）

The initial deformation of structures before the onset of buckling is usually very small in conventional concepts, and is always neglected in the conventional buckling theory(CBT) and numerical method(CNM). In this work, we find a class of structures from the emerging field of stretchable electronics, of which the initial deformation becomes large and essential for determining the critical buckling load. The buckling of these structures is referred to as the ‘finite-initial-deformation buckling'(FID buckling). Although great progress has been made for the buckling theory in the past hundred years, it is still challenging to analyze the FID buckling behaviors. Here, experimental stretch of a series of serpentine interconnects was firstly conducted as a representative example to show the FID buckling behaviors and the inapplicability of the CBT and CNM. The CNM can yield a huge error of 50% on the critical buckling load for the case with thickness-to-width ratio of the cross section h/b=0.6. Most importantly, a systematic theory(FID buckling theory) is developed to analyze the FID buckling behaviors of beams, with the coupling of bending, twist and stretch/compression. As a comparison, various theoretical and numerical methods are applied to three classic problems, including lateral buckling of a three-point-bending beam, lateral buckling of a pure bending beam and Euler buckling. Our FID buckling theory is able to give a good prediction, while the CBT(by Timoshenko et al.) and CNM(by commercial program packages) yield unacceptable results(with 70% error for a three-point-bending beam with h/b=0.8, for example)

CTD data processing method based on AUV (Autonomous Underwater Vehicle)

本发明公开一种无人无缆潜器（AUV）的CTD数据处理的方法。该发明适用于基于AUV获得的CTD数据处理。该发明分成2个阶段，第1阶段是使用AUV获得CTD测量数据，第2阶段是根据AUV获得的CTD数据进行数据处理。本发明操作简单，能够有效实现根据AUV获得的CTD数据自动处理，具有方便高效的优点

芯轴对弹簧不同预扩张量条件下弹簧离合器接合特性分析

芯轴对弹簧的预扩张量直接影响弹簧离合器的动静态性能,在建立弹簧离合器动力学有限元模型基础上,分析了芯轴对弹簧的不同预扩张量条件下的动态接合特性,得到了不同预扩张量下离合器的响应时间、接合时间以及弹簧径向位移、内圈Mises应力和压应力。结果表明,无预扩张量时,离合器弹簧与壳体不能稳定接合,导致工作失效;在具备稳定接合的条件下,预扩张量对离合器接合时间、响应时间的影响在毫秒级。增大预扩张量,弹簧径向位移增大,弹簧沿长度方向平均压应力下降、压应力分布更均匀

Path generation method based on GRD format map for underwater robot

本发明涉及水下机器人技术领域，尤其涉及一种基于GRD格式地图的路径生成方法，实现自主水下机器人在变化海洋环境下的路径规划。包括以下步骤：读取GRD格式的地图文件获得地图信息；将获得的地图信息载入到地图转化软件中，根据地图信息，进行地图信息识别；根据潜水器的起始点，规划出下一个航行点的坐标，通常下一个航行点使用的是极坐标，将极坐标转换成大地坐标系。与简单的路径规划方法比较，本方法具有更好的性能，在热液探测环境下更有优势，更能适应外界环境的改变，提高了AUV的工作能力。本方法移植方便，可以适用于各种水下机器人