基于改进正弦余弦算法的无线传感器节点部署优化

为了提高无线传感器网络（WSN）的性能，提出了一种基于改进正弦余弦算法（ESCA）的节点部署优化方法。首先，引入双曲正弦调节因子和动态余弦波权重系数，以平衡算法的全局探索与局部开发能力；然后，提出了一种基于拉普拉斯和高斯分布的变异策略，避免算法陷入局部最优。对于基准函数的优化实验结果表明，ESCA相比引力搜索算法、鲸鱼优化算法、基本正弦余弦算法（SCA）及其改进算法具有更高的收敛精度和收敛速度。最后，将ESCA应用于WSN节点部署优化，结果表明其优化覆盖率相比改进粒子群优化算法、外推人工蜂群算法、改进灰狼优化算法和自适应混沌量子粒子群算法分别提高了1.55个百分点、7.72个百分点、2.99个百分点和7.63个百分点，用更少节点便可达到相同目标精度。     

巨型工程机械子午线轮胎高强度、低生热胎面基部胶配方开发

通过对国外知名品牌37.00R57和40.00R57规格巨型工程机械子午线轮胎胎面基部胶组成分析和物理性能测试,对我公司巨型工程机械子午线轮胎胎面基部胶配方进行优化设计。新开发配方半成品和成品胶料动态损耗因子分别降低37.9%和26.6%,胶料物理性能达到竞品水平,成品轮胎TKPH提升13.6%。     

Balancing exploration and exploitation in differential evolution via variable scaling factors: An application to practical problems

Some optimization problems in the field of nuclear engineering, as for example the incore nuclear fuel management and a nuclear reactor core design, are highly multimodal, requiring techniques that overcome local optima, exploring the search space and promoting the exploitation of its most promising areas. The differential evolution algorithm (DE) relies mainly on the mechanism of mutation, where an individual is perturbed using the weighted difference (with the so-called “scaling factor” F) between two randomly chosen individuals. DE's canonical version employs a constant value of F. However, this parameter should be variable in order to balance the exploration and exploitation of the search space. In this work, we test some variable scaling factors from the literature and present the novel exponential scaling factor. These methods are applied to two problems: the aforementioned core design and the turbine balancing problem, which is an NP-hard (i.e. intrinsically harder than those that can be solved in nondeterministic polynomial time) combinatorial optimization problem that can be used to assess the potential of an algorithm to be applied to fuel management optimization. DE with variable scaling factors perform well in both problems, showing potential to be used in other nuclear science and engineering optimization problems.     

Fatigue strength evaluation of self-piercing riveted Al-5052 joints under different specimen configurations

In this study, static and fatigue tests were conducted using coach-peel, cross-tension and tensile–shear specimens with Al-5052 plates for evaluation of the fatigue strength of the SPR joints. For the coach-peel, cross-tension and tensile–shear geometries, the ratios of the fatigue endurance limit to static strength were 11%, 14% and 34%, respectively, assuming fatigue cycles of 10⁶ for an infinite lifetime. The equivalent stress intensity factor range can properly predict the current experimental fatigue lifetime. Fatigue crack initiation occurred due to fretting damage between the upper and lower sheets and between the rivet and these sheets.     

复频电导技术在隧洞超前探水中的应用

围岩富水带是隧道超前预报最关注的问题，目前，多使用电磁方法来预报围岩的含水性，但受到场地条件限制，面临掌子面条件、金属机具干扰、三维波场定位等诸多困难，特别是掌子面前方100 m范围内围岩的含水性预报，在国内外都是一个新的高难课题。在研究了岩体电导率与电容率复频特性的基础上，结合巴基斯坦NJ-TBM引水隧洞工程，开发了复频电导探水(CFC)技术。该技术基于电磁波反射与相干原理，选用100 kHz～10 MHz频率范围，采用电偶极子发射与阵列接收方式和偏移成像技术，突破了隧道内场地条件的限制。依据1/4相干波长确定含水体的位置，相干能量确定含水量的大小。在巴基斯坦NJ-TBM隧洞超前探水的应用，证明了该方法的可行性与有效性。      

Current–voltage and capacitance–voltage characteristics of Al Schottky contacts to strained Si-on-insulator in the wide temperature range

The electrical characteristics of Al/strained Si-on-insulator (sSOI) Schottky diode have been investigated using current–voltage (I–V) and capacitance–voltage (C–V) measurements in the wide temperature range of 200–400 K in steps of 25 K. It was found that the barrier height (0.57–0.80 eV) calculated from the I–V characteristics increased and the ideality factor (1.97–1.28) decreased with increasing temperature. The barrier heights determined from the C–V measurements were higher than those extracted from the I–V measurements, associated with the formation of an inhomogeneous Schottky barrier at the interface. The series resistance estimated from the forward I–V characteristics using Cheung and Norde methods decreased with increasing temperature, implying its strong temperature dependence. The observed variation in barrier height and ideality factor could be attributed to the inhomogeneities in Schottky barrier, explained by assuming Gaussian distribution of barrier heights. The temperature-dependent I–V characteristics showed a double Gaussian distribution with mean barrier heights of 0.83 and 1.19 eV and standard deviations of 0.10 and 0.16 eV at 200–275 and 300–400 K, respectively. From the modified Richardson plot, the modified Richardson constant were calculated to be 21.8 and 29.4 A cm⁻² K⁻² at 200–275 and 300–400 K, respectively, which were comparable to the theoretical value for p-type sSOI (31.6 A cm⁻² K⁻²).     

NIOSH national survey of long-haul truck drivers: Injury and safety

Approximately 1,701,500 people were employed as heavy and tractor-trailer truck drivers in the United States in 2012. The majority of them were long-haul truck drivers (LHTDs). There are limited data on occupational injury and safety in LHTDs, which prompted a targeted national survey. The National Institute of Occupational Safety and Health conducted a nationally representative survey of 1265 LHTDs at 32 truck stops across the contiguous United States in 2010. Data were collected on truck crashes, near misses, moving violations, work-related injuries, work environment, safety climate, driver training, job satisfaction, and driving behaviors. Results suggested that an estimated 2.6% of LHTDs reported a truck crash in 2010, 35% reported at least one crash while working as an LHTD, 24% reported at least one near miss in the previous 7 days, 17% reported at least one moving violation ticket and 4.7% reported a non-crash injury involving days away from work in the previous 12 months. The majority (68%) of non-crash injuries among company drivers were not reported to employers. An estimate of 73% of LHTDs (16% often and 58% sometimes) perceived their delivery schedules unrealistically tight; 24% often continued driving despite fatigue, bad weather, or heavy traffic because they needed to deliver or pick up a load at a given time; 4.5% often drove 10 miles per hours or more over the speed limit; 6.0% never wore a seatbelt; 36% were often frustrated by other drivers on the road; 35% often had to wait for access to a loading dock; 37% reported being noncompliant with hours-of-service rules (10% often and 27% sometimes); 38% of LHTDs perceived their entry-level training inadequate; and 15% did not feel that safety of workers was a high priority with their management. This survey brings to light a number of important safety issues for further research and interventions, e.g., high prevalence of truck crashes, injury underreporting, unrealistically tight delivery schedules, noncompliance with hours-of-service rules, and inadequate entry-level training.     

Fundamental analysis of recombinant human epidermal growth factor in solution with biophysical methods

Correlation of thermodynamic and secondary structural stability of proteins at various buffer pHs was investigated using differential scanning calorimetry (DSC), dynamic light scattering (DLS) and attenuated total reflection Fourier-transform infrared spectroscopy (ATR FT-IR). Recombinant human epithelial growth factor (rhEGF) was selected as a model protein at various pHs and in different buffers, including phosphate, histidine, citrate, HEPES and Tris. Particle size and zeta potential of rhEGF at each selected pH of buffer were observed by DLS. Four factors were used to characterize the biophysical stability of rhEGF in solution: temperature at maximum heat flux (T_m), intermolecular β-sheet contents, zeta size and zeta potential. It was possible to predict the apparent isoelectric point (pI) of rhEGF as 4.43 by plotting pH against zeta potential. When the pH of the rhEGF solution increased or decreased from pI, the absolute zeta potential increased indicating a reduced possibility of protein aggregation, since T_m increased and β-sheet contents decreased. The contents of induced intermolecular β-sheet in Tris and HEPES buffers were the lowest. Thermodynamic stability of rhEGF markedly increased when pH is higher than 6.2 in histidine buffer where T_m of first transition was all above 70?°C. Moreover, rhEGF in Tris buffer was more thermodynamically stable than in HEPES with higher zeta potential. Tris buffer at pH 7.2 was concluded to be the most favorable.     

Classification of quasigroups based on period factors

Edon80 is a stream cipher design that had advanced to the third and last phase of the eSTREAM project. The core of the cipher consists quasigroup string e-transformations and it employs four quasigroups of order 4. The employed quasigroups have influence on the period of the keystream. There are 576 quasigroups of order 4 in total which have different period factors. The four quasigroups used in Edon80 were chosen by numerous computer experiments. In this paper, based on permutation groups, we give a theory criterion for the determination of quasigroups and give a complete classification for the 576 quasigroups of order 4 according to their period factors.