A facile method to fabricate tough hydrogel with ultra-wide adjustable stiffness,stress, and fast recoverability

In this article, we report a synergistic strategy to develop dual physically cross-linked tough hydrogels via one-pot bulk copolymerization of N-vinyl-2-pyrrolidone, acrylic acid, and stearyl methylacrylate (SMA) without any adscititious surfactant. Due to synergic effects of hydrogen bonding and hydrophobic association, the resulted dual physically cross-linked hydrogels (DP Gel) with ultra-wide range adjustable Young's modulus (0.08–45.6 MPa), tensile stress (0.7–6.9 MPa), and toughness (3.3–23.1 MJ m⁻³). Stretching to 300%, DP Gel exhibited fast recoverability that remained ~95% of initial dissipated energy after resting in 60 °C for 3 min. Finally, scanning electron microscopy revealed that the microstructure of hydrogel changed from phase separation structure to micro phase separation as SMA added, which accounted for excellent performance of DP Gel. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2018 , 56, 1469–1474     

橫觀各向同性弹性体的振动问题

-.引言 各向异性弹性体中平面波与表面波的传播虽经不少学者研究过,但是这类物体的一般振动问题却很少有人提起。本文的目的在于简化横观各向同性弹性体的振动问题的一般方程。採用与前文相同的方法,我们将位移用两个函数φ和F来表示,并且导得它们所适合的方程。φ可以用普通的波函数表示,但是在一般情况下F却不能用普通的波函数表示。     

Measurement of the KLL Dielectronic Recombination Resonances in He-like to C-like Kr Ions

The KLL dielectronic recombination processes of highly charged He-like to C-like Kr ions have been studied experimentally. The measurement was performed on the newly developed Shanghai electron beam ion trap （Shanghai-EBIT） facility. Characteristic x-rays from both dielectronic recombination and radiative recombination are detected as the electron beam energy is scanned through the resonances. The KLL resonant strengths obtained are 5.41×10^-19, 4.33×10^-19, 3.59×10^-19, 2.05×10^-19 and 0.98×10^-19 cm^2 eV for He-like to C-like Kr ions, respectively.     

亚音速轴流压气机转子非轴对称轮毂端壁的数值研究

修改端壁型线是减小二次流损失提高压气机性能的有效方法之一.本文针对某高亚音速压气机转子,首先利用三角函数造型法完成了非轴对称轮毂端壁造型,然后对带非轴对称端壁结构的轴流压气机内部流场进行了详细的数值模拟,数值计算所获得的总性能与试验结果符合较好,该非轴对称轮毂端壁结构的引入能使得压气机的峰值效率提高约0.3285%.详细分析了非轴对称端壁结构对压气机内部流场结构的影响,结果表明:非轴对称轮毂端壁结构的采用能够改善轮毂端壁附近载荷分布,有效地降低叶片通道的二次流流动,从而提高轴流压气机的性能.     

M-RNA碱基复合物(M=Ca+和Mg+)特征振动的密度泛函理论分析

采用密度函数理论的B3LYP交换关联能泛函在6-311+G(2df,2p)基组水平上,优化计算了Ca+,Mg+与RNA碱基嘧啶各同分异构体形成稳定复合物的结构,发现其中C1M,T1M和U1M(M=Ca+和Mg+)为最稳定复合物,并对这些复合物红外振动进行了计算.计算结果显示碱基嘧啶单体主要存在的两个红外特征振动,是由环振动和环外氧原子及与其成键的环上碳原子之间产生伸缩振动引起的.当形成复合物时,由于离子的参与,使单体碱基分子的振动情况发生了改变,主要表现在离子倾向于与环外负电子原子N和O原子成键,使与离子直接作用环外原子参与的特征振动频率减小,谱线红移;不与离子直接作用环外原子引起的特征振动频率增大,谱线蓝移.     

一类变论域自适应模糊控制器

目前常用的自适应模糊控制器存在控制精度不高和调整时间长等问题.变论域自适应模糊控制器能够显著提高控制精度并缩短其调整时间,但其控制效果对一组完备的初始模糊规则的依赖,限制了其应用的范围.针对上述问题,本文提出了一种推理规则前件论域可变,后件峰点自适应的自适应模糊控制器.Lyapnuov综合分析法证明新的控制器具有全局稳定性,并通过仿真实验表明,新控制器不仅能够提高控制精度,而且较为合理地回避了对初始模糊规则的依赖性,扩展了变论域模糊控制的适用范围.     

Baseline drift effect on the performance of neutron and γ ray discrimination using frequency gradient analysis

Frequency gradient analysis (FGA) effectively discriminates neutrons and γ rays by examining the frequency-domain features of the photomultiplier tube anode signal. This approach is insensitive to noise but is inevitably affected by the baseline drift similar to other pulse shape discrimination methods. The baseline drift effect is attributed to factors such as power line fluctuation, dark current, noise disturbances, hum, and pulse tail in front-end electronics. This effect needs to be elucidated and quantified before the baseline shift can be estimated and removed from the captured signal. Therefore, the effect of baseline shift on the discrimination performance of neutrons and γ rays with organic scintillation detectors using FGA is investigated in this paper. The relationship between the baseline shift and discrimination parameters of FGA is derived and verified by an experimental system consisting of an americium-beryllium source, a BC501A liquid scintillator detector, and a 5 GSample/s 8-bit oscilloscope. The theoretical and experimental results both show that the estimation of the baseline shift is necessary, and the removal of baseline drift from the pulse shapes can improve the discrimination performance of FGA.     

瘦长红珊瑚的振动光谱研究

瘦长红珊瑚是台湾贵珊瑚中最主要的品种,其颜色分布独具特色。以瘦长红珊瑚为研究对象,采用电子探针、X射线粉晶衍射、红外光谱和拉曼光谱对其进行测试分析。结果显示样品的矿物成分为高镁方解石,次要成分的含量稳定,样品中的生物成因方解石存在晶格畸变。实验探测到的代表有机质成分的1 517/1 128cm-1和1 296/1 016cm-1成套谱峰表明样品的红色与该有机成分有关。     

Ultrasonic Barker-coded excitation method with attenuation matching

In order to increase the ability of ultrasound to penetrate high-attenuation medium,an attenuation matching method of ultrasonic Barker-coded excitation is prop...     

Multi-Image Encryption Algorithm Based on Cascaded Modulation Chaotic System and Block-Scrambling-Diffusion

To address the problem of a poor security image encryption algorithm based on a single chaotic map, this paper proposes a cascade modulation chaotic system (CMCS) that can generate multiple chaotic maps. On this basis, a multi-image encryption algorithm with block-scrambling-diffusion is proposed using CMCS. The algorithm makes full use of the features of CMCS to achieve the effect of one encryption at a time for images. Firstly, the key-value associated with the plaintexts is generated using a secure hash algorithm-512 (SHA-512) operation and random sequence, and the three images are fully confused by the double scrambling mechanism. Secondly, the scrambled image is converted into a bit-level matrix, and the pixel values are evenly distributed using the bit-group diffusion. Finally, the non-sequence diffusion of hexadecimal addition and subtraction rules is used to improve the security of the encryption algorithm. Experimental results demonstrate that the encryption algorithm proposed in this paper has a good encryption effect and can resist various attacks.