闹市区高层建筑物爆破拆除的实践

待拆建筑物为16层高的剪力墙现浇整体结构,其高宽比较小为1.78(48∶27),一旦处理不当就会倾而不倒,而且塌落空间只有北侧的38m。经研究决定采用折叠爆破方案,向北倾倒,并运用毫秒延时起爆技术解决了倾而不倒问题。爆破结果证明,爆破方案及采取的延时技术是正确的。     

0.14 THz折叠波导行波管的设计与实验

对折叠波导慢波结构进行了研究,对其色散特性和耦合阻抗进行分析,并设计了输能窗和电子光学系统,在此基础上进行了粒子模拟的束波互作用计算。通过设计,对0.14 THz 行波管进行了制管工艺的研究,包括慢波结构的加工和焊接等,完成了热测实验。在电压为16.3 kV,电子流通率为74%条件下,测试得到最大饱和输出功率3.1 W,输出频率140.08 GHz,增益27 dB,最大功率半带宽2.82 GHz。     

短毫米波折叠波导慢波结构精密加工技术

介绍了短毫米波折叠波导慢波结构的精密加工技术的进展情况。利用精密电火花加工工艺方法,通过大量的试验实现了短毫米波折叠波导慢波结构的加工,并用于了行波管的研制。     

ORICRETE: Modeling support for design and manufacturing of folded concrete structures

The paper presents a flexible and efficient modeling approach to the simulation of the folding process of general crease patterns. The development of the model has been motivated by the need to provide support for targeted design and efficient manufacturing of shell structures inspired by the origami technique. This type of structures is becoming increasingly popular in many engineering disciplines and has been referred to as origamics. In the present work the folding technique is used to produce spatial structures from continuously reinforced thin-walled cementitious composite plates without the need to construct curved spatial formworks. In order to support the targetted design and manufacturing of folded concrete (oricrete) structures numerical model has been formulated as an optimization framework with several types of optimality conditions and equality constraints. The model is used both for form-finding of the spatial structure and for the realization of the manufacturing process.     

An efficient construction of one-to-many node-disjoint paths in folded hypercubes

A folded hypercube is basically a hypercube with additional links augmented, where the additional links connect all pairs of nodes with longest distance in the hypercube. In an n$n$-dimensional folded hypercube, it has been shown that n+1$n+1$ node-disjoint paths from one source node to other n+1$n+1$ (mutually) distinct destination nodes, respectively, can be constructed in O(n⁴)$O\left(n^4\right)$ time so that their maximal length is not greater than ⌈n/2⌉+1$\lceil n/2\rceil +1$, where n+1$n+1$ is the connectivity and ⌈n/2⌉$\lceil n/2\rceil$ is the diameter. Besides, their maximal length is minimized in the worst case. In this paper, we further show that by minimizing the computations of minimal routing functions, these node-disjoint paths can be constructed in O(n³)$O\left(n^3\right)$ time, which is more efficient, and is hard to be reduced because it must take O(n³)$O\left(n^3\right)$ time to compute a minimal routing function by solving a corresponding maximum weighted bipartite matching problem with the best known algorithm.     

Compact dual-band bandstop filter using folded resonator

A compact dual-band bandstop filter composed of main transmission line and four folded resonators is presented. Through analyzing the structure of folded resonator, it is found that the main transmission line connected with two proposed folded resonators exhibits the characteristic of band-rejection. Simulated results show that the center frequency of stopband is 2.72 GHz. Then, through adding another pair of folded resonator; a compact dual-band bandstop filter is achieved. Simulated results demonstrate that transmission poles are induced to have better selectivity. Additionally, in order to explain the mechanism of proposed structure, the LC equivalent circuit, analysis of parametric effect and surface current distributions are given. Due to the folded structure, the filter dimensions are reduced and the adjustable stopband is another feature. By virtue of optimization, proposed structure is fabricated. Measured results agree well with the simulation.     

The super spanning connectivity and super spanning laceability of the enhanced hypercubes

A k -container C(u,v) of a graph G is a set of k disjoint paths between u and v. A k-container C(u,v) of G is a k ^* -container if it contains all vertices of G. A graph G is k ^* -connected if there exists a k ^*-container between any two distinct vertices of G. Therefore, a graph is 1^*-connected (respectively, 2^*-connected) if and only if it is Hamiltonian connected (respectively, Hamiltonian). A graph G is super spanning connected if there exists a k ^*-container between any two distinct vertices of G for every k with 1≤k≤κ(G) where κ(G) is the connectivity of G. A bipartite graph G is k ^* -laceable if there exists a k ^*-container between any two vertices from different partite set of G. A bipartite graph G is super spanning laceable if there exists a k ^*-container between any two vertices from different partite set of G for every k with 1≤k≤κ(G). In this paper, we prove that the enhanced hypercube Q _n,m is super spanning laceable if m is an odd integer and super spanning connected if otherwise.

A new family of CMOS inverter-based OTAs for biomedical and healthcare applications

This paper presents a new family of innovative operational transconductance amplifier (OTA) topologies based on CMOS inverter structures, with improved gain and energy-efficiency. This new family of OTA designs is suitable for biomedical and healthcare circuits and systems, due to the high energy-efficiency, improved gain and low level of noise contribution, when compared to the state-of-the-art in this field. In this paper, two fully-differential implementations are presented, a first one with a double CMOS branch biased by two pairs of voltage-combiners structures in both NMOS and PMOS configurations, and a second one with folded voltage-combiners specifically targeting low voltage applications, e.g., supplies below 1 V. The usage of voltage-combiners to bias the OTAs improves the gain and the gain-bandwidth product, therefore improving the energy-efficiency figure-of-merit. High values of figure-of-merit are achieved in both implementations, i.e., more than 1600 MHz × pF/mA and 2000 MHz × pF/mA, gain values above 53 dB and 50 dB under supply sources of 2 V and 0.7 V respectively. The folded voltage-combiners biased OTA is able to operate correctly under a voltage supply down to 0.7 V with proper DC biasing. The results are finally compared with state-of-the-art in this field and the potential of the circuits is fulfilled using a state-of-the-art layout-aware integrated-circuit optimization framework, AIDA, particularly relevant in order to overcome the device stacking problematic for lower voltages.     

钢筋混凝土烟囱定向爆破参数与效果的DDA模拟

通过一座钢筋混凝土烟囱双向折叠拆除爆破实例的DDA模拟计算表明,在倾倒过程和爆破效果等方面,模拟计算结果与实际爆破具有很好的相似性。证明了运用DDA程序对钢筋混凝土烟囱定向爆破参数与爆破效果的关系进行数值模拟,可得到比较合理的爆破参数,从而可进行爆破效果的爆前预测,对爆破设计、施工和安全防护等具有指导意义。     

The measurement of a process capability for folded normal process data

There are two approaches to estimate the nonconforming percentage and process capability indices which are commonly used to measure the ability of a process to manufacture products meeting a required specification. The most commonly used approaches are based on the assumption that the process is normally distributed. If the process is not normal with a skewed distribution, but normal-based techniques are used to estimate process capability indices or fraction nonconforming, serious errors can result. Basically, non-normal process data, such as folded normal process data, is common in mechanical industries. In this paper, we propose one procedure to evaluate the process capability from folded normal data, by solving the true process mean and process standard deviation of the underlying normal distribution. A numerical result based on the proposed approach is illustrated.