建设项目含钢量经济性理解与常见误区

含钢量对建设项目的经济性分析有着重要的作用,但在日常应用中对含钢量经济性常有不同的理解。为此,举例阐释含钢量的影响因素和应用误区,并给出含钢量的统计方式,以方便经济性分析对比。     

电缆测井高速遥传系统中比特分配与星座映射的实现

通过在现有的硬件平台提高电缆的传输速率,优化系统硬件平台内部资源分配。采用"注水"算法进行信道比特及能量联合分配。该方法与子信道能量均匀分配方式相比,链路层传输速率提高9.13%。设计了一种OFDM系统中星座映射的新方法,与原有方法相比,新方法大大节约了硬件存储资源。     

云环境下安全密文区间检索方案的新设计

针对目前密文区间检索多次断言存在信息泄露等问题,有单断言的密文区间检索方案(SRQSAE方案),并证明方案在唯密文攻击下的隐私安全性。对SRQSAE方案的安全性进行了分析,分析结果表明SRQSAE方案并不能隐藏搜索关键字的大小关系排序。通过在每次生成搜索索引或陷门消息时引入不同随机数的方法,提出了单断言的密文区间检索新方案。新方案对搜索关键字、区间的大小关系提供了很好的隐私保护;而且新方案在安全性提高的同时,并不以损失效率为代价。     

Coded transmissions for space links affected by solar scintillation: Baseband analysis

A thorough analysis of the behavior of error‐correcting codes over space links affected by solar scintillation is presented. The relevant channel parameters are fixed through the development of a model based on real missions' data. Both telecommand and telemetry links are considered in fast and slow fading conditions. Besides classical coherent modulation schemes, the possibility to use noncoherent modulation schemes is considered, to eliminate the problem of phase tracking. For the case of channels with very slow fading, the use of external interleavers or erasure coding is proposed to cope with error bursts.     

Highly Bendable and Rotational Textile Structure with Prestrained Conductive Sewing Pattern for Human Joint Monitoring

Human joints have respective ranges of motion and joint forces corresponding to each kind of joint; this necessitates considerations of the characteristics of human joints to fabricate wearable strain sensors conformable to the human body, and capable of precisely monitoring complex motions of the human body. In the present study, the “all textile‐based highly stretchable structure” that is capable of precisely sensing motions (folding and rotation) of the human joints (finger, wrist, elbow, spine, and knee) is fabricated by optimizing patterns (straight, blind, and zigzag) of conductive yarns employed as the conductive part of the strain sensor, and several textile substrates (braided elastic fabric, knit fabric, and woven fabric), having preferable elasticity and conformability employed for the fabrication of strain sensors suitable for human joints. In particular, the technology, enabling the prestraining of textile substrate, is exploited to fabricate a strain sensor that is capable of outputting selective signals corresponding to the folding motion of the spinal joint over a predetermined angle of motion, and the gait pattern of the wearer of the sensor, attached to his or her knee joint doing folding and rotational motions, is analyzed.     

Controllable 1D Patterned Assembly of Colloidal Quantum Dots on PbSO4 Nanoribbons

Control of the 1D self‐assembly pattern of colloidal quantum dots (QDs) on PbSO₄ nanoribbon (NRb) templates is achieved. The internal structure of the NRbs is investigated by X‐ray diffraction, revealing the isotropic packing of the PbSO₄ nanoclusters in the NRbs. Colloidal QDs in a chloroform/hexane mixture are adsorbed onto the region close to the edges of the NRbs and form a 1D assembly of straight single line or double lines by controlling the amount of OAm. This is the first demonstration of a densely packed 1D self‐assembly of colloidal QDs with a straight line pattern without the use of any molecular bridge or adhesive. Atomic force microscopy measurements of the NRbs show depressions in the phase profile along the width of the NRbs, corresponding to the position of the 1D QD chain. The amount of adsorbed QDs on the NRbs in solution decreases as the addition of OAm increases, suggesting that additional OAm prevents interaction between the QDs and NRbs but facilitates the uniform adsorption of the 1D assembly. The low‐dimensional self‐assembly of colloidal QDs in this study opens up the possibility for the creation of anisotropically assembled QD superstructures.     

Injury Analysis of Vehicle-Pedestrian Collision Based on Orthogonal Experiments

This paper studies the influence of different factors on pedestrian head injury in vehicle-pedestrian collisions. PC-Crash software is used to construct simulation experiments under ten factors. The research shows that the injury to pedestrians in reverse impact is greater than that to pedestrians in forward impact. With the acceleration of vehicle speed, the HIC value of pedestrians will increase with the increase of the height of the front hood from the ground. When the vehicle speed is less than 40 km/h, the injury to pedestrians in a forward-leaning emergency posture is smaller, and the injury to a standing emergency posture is the highest.     

Assessing the impact of non-ideal optical factors on optimized solar dish collector system with mirror rearrangement

An optimized solar dish collector (OPSDC) system was proposed in our previous work, which can achieve excellent the optical efficiency and flux uniformity under ideal optics. On this basis, the impacts of the non-ideal optical factors on the optical performance of OPSDC system with a cylindrical and conical receiver are studied in detail and compared with the conventional solar dish collector (COSDC) system in this paper. Where the non-ideal optical factors considered are relatively comprehensive, including the mirror slope error, tracking error, installation error of the mirror and receiver, and receiver's absorptivity degeneration. An optical model with the non-ideal optical factors is built in detail by the ray tracing method, and the corresponding ray tracing codes are developed and verified by literatures and optical software OptisWorks 2012. The results show that the OPSDC system not only has a significantly smaller peak local concentration ratio (LCR) and non-uniformity factor than the COSDC system under the same non-ideal optical factor, but also has excellent optical performance. This means that OPSDC system can effectively avoid the heat absorber generating high-temperature hot spots, thus significantly improving its working reliability and service lifetime. In addition, the tracking error, installation error of the receiver and mirror all lead to the increase of the peak LCR and non-uniform factor, while the mirror slope error and absorber's absorptivity degeneration are conducive to reducing the peak LCR and non-uniform factor. This work can provide a reference for error control of COSDC system and OPSDC system in manufacturing, installation and operation.     

基于Nef的组网雷达包络三维可视化研究

提出了采用基于CGAL库定义的Nef多面体数据结构,并结合Nef多面体之间的三维布尔操作来解决组网雷达探测范围相互重叠的雷达包络可视化问题。试验测试结果表明,每组试验样本求交后的三角网格正常,可视化效果好,满足项目应用需求。