A deterministic sequential maximin Latin hypercube design method using successive local enumeration for metamodel-based optimization

Space-filling and projective properties of design of computer experiments methods are desired features for metamodelling. To enable the production of high-quality sequential samples, this article presents a novel deterministic sequential maximin Latin hypercube design (LHD) method using successive local enumeration, notated as sequential-successive local enumeration (S-SLE). First, a mesh-mapping algorithm is proposed to map the positions of existing points into the new hyper-chessboard to ensure the projective property. According to the maximin distance criterion, new sequential samples are generated through successive local enumeration iterations to improve the space-filling uniformity. Through a number of comparative studies, several appealing merits of S-SLE are demonstrated: (1) S-SLE outperforms several existing LHD methods in terms of sequential sampling quality; (2) it is flexible and robust enough to produce high-quality multiple-stage sequential samples; and (3) the proposed method can improve the overall performance of sequential metamodel-based optimization algorithms. Thus, S-SLE is a promising sequential LHD method for metamodel-based optimization.     

One weight $$\mathbb {Z}_2\mathbb {Z}_4$$ additive codes

We study one weight \(\mathbb {Z}_2\mathbb {Z}_4\) additive codes. It is shown that the image of an equidistant \(\mathbb {Z}_2\mathbb {Z}_4\) code is a binary equidistant code and that the image of a one weight \(\mathbb {Z}_2\mathbb {Z}_4\) additive code, with nontrivial binary part, is a linear binary one weight code. The structure and possible weights for all one weight \(\mathbb {Z}_2\mathbb {Z}_4\) additive codes are described. Additionally, a lower bound for the minimum distance of dual codes of one weight additive codes is obtained.     

金属薄膜屈服强度的鼓包法表征

本文采用鼓包法研究金属薄膜的屈服强度,对具有圆形自由窗口的镍薄膜一侧施加压力,薄膜受压变形的全场形貌用数字散斑相关法(DSCM)进行测量,并应用板壳理论分析小挠度变形下膜内应力分布情况。结果表明:圆形薄膜受压时首先从边缘开始屈服,从压力-挠度曲线偏离线性关系的临界点得到金属镍膜的屈服强度为467MPa,这和单轴拉伸法测量所得到的屈服强度值吻合较好。     

Electric Power Generation through the Direct Interaction of Pristine Graphene‐Oxide with Water Molecules

Converting ubiquitous environmental energy into electric power holds tremendous social and financial interests. Traditional energy harvesters and converters are limited by the specific materials and complex configuration of devices. Herein, it is presented that electric power can be directly produced from pristine graphene oxide (GO) without any pretreatment or additives once encountering the water vapor, which will generate an open‐circuit‐voltage of up to 0.4–0.7 V and a short‐circuit‐current‐density of 2–25 µA cm^?2 on a single piece of GO film. This phenomenon results from the directional movement of charged hydrogen ions through the GO film. The present work demonstrates and provides an extremely simple method for electric energy generation, which offers more applications of graphene‐based materials in green energy converting field.     

Efficient defect-controlled photocatalytic hydrogen generation based on near-infrared Cu-In-Zn-S quantum dots

The development of photocatalysts that can effectively harvest visible light is essential for advances in high-efficiency solar-driven hydrogen generation. Herein, we synthesized water soluble CuInS₂ (CIS) and Cu-In-Zn-S (CIZS) quantum dots (QDs) by using one-pot aqueous method. The CIZS QDs are well passivated by glutathione ligands and are highly stable in aqueous conditions. We subsequently applied these QDs as a light harvesting material for photocatalytic hydrogen generation. Unlike most small band gap materials that show extremely low efficiency, these new QDs display remarkable energy conversion efficiency in the visible and near-infrared regions. The external quantum efficiency at 650 nm is ～1.5%, which, to the best of our knowledge, is the highest value achieved until now in the near-infrared region.

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茶末/CMC-Na/AL-Na复合膜制备及性能测定

目的 为改善传统保鲜膜带来的环境污染问题,开发出具有较好力学性能和抗菌性的食品包装材料提供理论依据。方法 采用海藻酸钠(AL-Na)和羧甲基纤维素钠(CMC-Na)为主要成膜材料,辅助添加茶末通过流延成膜法制备复合膜,以拉伸强度、断裂伸长率等为依据,通过单因素和响应面试验确定茶末/CMC-Na/AL-Na复合膜的最佳工艺。结果 当CMC-Na与AL-Na的体积比为84∶16、茶末添加量为1.43%、干燥温度为50 ℃、干燥时间为7 h时,复合膜综合性能最优,拉伸强度为16.60 N/mm²,断裂伸长率为19.11%,具有较好的力学性能、耐水性、抗氧化性和抑菌性。结论 制备的茶末/ CMC-Na/AL-Na复合膜具有较好的力学性能和抗氧抑菌性能。     

Fabrication of large-volume microfluidic chamber embedded in glass using three-dimensional femtosecond laser micromachining

We report on fabrication of large-volume, square-shaped microfluidic chamber embedded in glass by scanning a tightly focused femtosecond laser beam inside a porous glass immersed in water. After the hollow structure is created in the porous glass substrate, the fabricated glass sample is post-annealed at 1,050°C during which it can be sintered into a compact glass. By the use of this technique, a 1 mm × 1 mm × 100 μm microchamber connected to four microfluidic channels is created inside the transparent glass substrate, showing that our technique allows for fabrication of not only thin channel structures with arbitrary lengths and configurations, but also hollow structures with infinitely large sizes.     

Die shape optimisation for net-shape accuracy in metal forming using direct search and localised response surface methods

In this paper, three direct search algorithms, i.e. a modified simplex, random direction search and enhanced Powell’s methods together with a new localised response surface method are presented and applied to solve die shape optimisation problems for achieving net-shape accuracy in metal forming processes. The main motivation is to develop efficient and easy to implement optimisation algorithms in metal forming simulations which often involve complex tool and workpiece interaction and coupled thermal and mechanical analysis. Three case studies are presented including a simple upsetting, a 2D blade forging and a forward extrusion problem. In all cases, the objective was to achieve net-shape accuracy of the formed parts, one important criterion for precision forming. C+ + programs were developed to implement these algorithms and to automatically integrate optimisation computation and forging simulation. The optimisation results from the three case problems show that direct search based methods especially the modified simplex and the localised response surface methods are computationally efficient and robust for net-shape forging and extrusion optimisation problems. It is also suggested that these methods can be used in more complex forging problems where die shape design and optimisation are essential for achieving net-shape accuracy.     

基于ARM-Linux的矿井安全监控系统设计与实现

以当前矿井安全的现状与需求为出发点,对基于ARM-Linux的矿井安全监测控制系统进行深入研究,提出基于嵌入式技术的矿井安全监控系统的总体设计方案;通过构建该平台的模型和分析嵌入式终端的体系结构,阐述了在以Linux操作系统和ARMS3C2410X处理器为核心的终端软硬件基础上,系统各主要功能模块的实现;在所构建的矿井安全监控硬件平台上,应用HTTP协议,成功实现了远程终端对井上监控终端的控制与访问.