基于频带分解和距离加权的单矢量水听器浅海被动测距方法研究

本文针对浅海环境下中低频宽带脉冲声源被动测距问题, 提出了一种声压和水平振速联合处理的被动测距方法. 在浅海波导中, 声压和质点振速的自相关函数卷绕(warping)谱具有稳定的频率特征. 声压和水平振速的自相关卷绕谱具有相同的准线谱特征, 垂直振速自相关卷绕谱具有宽谱叠加线谱的特征, 与声压自相关卷绕谱相比, 其尖峰个数比更多, 且尖峰宽度更宽. 利用引导源, 本文提出了基于频带分解和距离加权的声压和水平振速联合被动测距方法. 利用该方法对2008年冬季青岛海域综合实验中单矢量水听器接收的气枪信号进行处理, 结果表明, 该方法能够实现气枪声源的有效测距. 与传统单声压水听器被动测距方法相比, 该方法可以有效减小代价函数的主瓣宽度、提高测距精度.     

局域环境中微波等离子体电子密度诊断实验研究

为了研究局域真空环境中微波等离子体喷流电子数密度的分布规律及其影响因素,利用发射/郎缪尔探针测量等离子体的空间电位,再测量等离子体的电流-电压特性曲线,根据空间电位测量结果,在等离子体的电流-电压特性曲线上能准确地获取饱和电流,从而处理出电子数密度.最后的诊断实验表明：在有约束边界条件下,微波等离子体发生器以60 W以下的微波功率击穿流量范围是21—105 mg/s的氩气时,所产生的喷流中电子数密度分布在8.8×10¹⁴—7.53×10¹⁶/m^{3关键词： 等离子体诊断技术 等离子体基本过程 等离子体基本特性}     

Relaxation of Magnetic Nanoparticle Chain without Applied Field

The relaxation of a one-dimensional magnetic nanoparticle linear chain with lattice constant $a$ is investigated in absence of applied field. There is an equilibrium state (or steady state) where all magnetic moments of particles lie along the chain (x-axis), back to which the magnetic nanoparticle chain at other state will relax. It is found that the relaxation time T_x is determined by T_x=10^β× a³. This relaxationis compared with that of single magnetic nanoparticle system.     

A Study on Consumers’ Visual Image Evaluation of Wrist Wearables

This study aimed to investigate consumers’ visual image evaluation of wrist wearables based on Kansei engineering. A total of 8 representative samples were screened from 99 samples using the multidimensional scaling (MDS) method. Five groups of adjectives were identified to allow participants to express their visual impressions of wrist wearable devices through a questionnaire survey and factor analysis. The evaluation of eight samples using the five groups of adjectives was analyzed utilizing the triangle fuzzy theory. The results showed a relatively different evaluation of the eight samples in the groups of “fashionable and individual” and “rational and decent”, but little distinction in the groups of “practical and durable”, “modern and smart” and “convenient and multiple”. Furthermore, wrist wearables with a shape close to a traditional watch dial (round), with a bezel and mechanical buttons (moderate complexity) and asymmetric forms received a higher evaluation. The acceptance of square- and elliptical-shaped wrist wearables was relatively low. Among the square- and rectangular-shaped wrist wearables, the greater the curvature of the chamfer, the higher the acceptance. Apparent contrast between the color of the screen and the casing had good acceptance. The influence of display size on consumer evaluations was relatively small. Similar results were obtained in the evaluation of preferences and willingness to purchase. The results of this study objectively and effectively reflect consumers’ evaluation and potential demand for the visual images of wrist wearables and provide a reference for designers and industry professionals.     

无电沉积高密度钯金属纳米线阵列

利用介孔氧化硅薄膜作为模板,通过无电沉积路线在介孔薄膜孔道内合成了高密度钯金属纳米线阵列.利用介孔薄膜导向剂的疏水区作为载体,引进钯金属疏水化合物并经热解和还原,得到钯微粒,以此为催化中心引发无电沉积,避免了传统无电沉积复杂的工艺过程.结果表明,纳米线尺寸均一,长径比大于60,完全填充了介孔薄膜的孔道,并可通过介孔模板孔径的选择对纳米线直径加以调控.     

有机锡催化苯氨基甲酸甲酯分解的研究

对几种锡化合物催化苯氨基甲酸甲酯(MPC)热分解制苯基异氰酸酯(PI)反应进行了研究, 发现二丁基氧化锡具有较高的催化活性. 用HPLC-MS确定了分解的未知副产物为二苯基碳化二亚胺(DPCD). 分析认为生成N,N'-二苯基脲(DPU)和DPCD的反应为合成PI的主要竞争反应. 常压下以Bu₂SnO为催化剂时的适宜反应条件为以邻二氯苯(ODCB)为溶剂, 溶剂用量为MPC用量的15倍(质量比), Bu₂SnO用量为MPC用量的0.075 (摩尔比), 反应时间1 h. 此条件下MPC转化率为85.17%, PI收率为67.65%.     

电解煤浆制氢阳极的制备及电催化活性研究

将钛片进行预处理, 用处理后的钛片作为电极基体, 然后用循环伏安法在钛基体上沉积制备了Pt/Ti, Pt-Ru/Ti, Pt-Ir/Ti, Pt-Ru-Ir/Ti催化电极, 通过扫描电镜(SEM)、X射线衍射(XRD)、电子能谱(EDS)以及等离子发射光谱(ICP)等方法对所制备电极进行了表征, 包括电极表面形貌、组分的沉积状态、催化层成分组成以及电极寿命等; 在煤浆电解过程中, 采用两电极体系, 对所制备电极的电催化活性进行了测试. 结果表明: 所制备的电极催化活性都高于同面积的铂片电极, 含有Ru, Ir的二元催化电极的活性好于镀铂催化电极. 在一定范围内, 随着Ru元素比例增大, 电极活性增强, 而Ir元素含量过大, 电极活性反而稍微降低, 所以Pt-Ir(1∶0.5)/Ti, Pt-Ru(1∶5)/Ti两电极的催化活性相对较好. 本文所制备的三元催化电极的催化活性低于二元催化电极. Pt-Ru/Ti电极催化活性最好, 相同条件下具有最大的电解电流, H₂的电解效率可达95%以上.     

Interlayer transport of an electron in bilayer graphene with phonon-induced lattice distortion in the presence of biased potential

The interlayer transport of an electron in bilayer graphene influenced by a phonon in the presence of a biased potential is investigated using the tight-binding approach. The in-plane optical mode E2g and out-of-plane optical mode B1g associated with the applied biased potential are considered to compute and discuss the interlayer transport probability of an electron initially localized on the bottom layer at the Dirac point in the Brillouin zone. Without the biased potential, the interlayer transport probability is equal to 0.5 regardless of the phonon displacement except for a few special cases. Applying a biased potential to the layers, we find that in different phonon modes the function of the transport probability with respect to the applied biased potential and phonon displacement is complex and various, but on the whole the transport probability decreases with the increase in the absolute value of the applied biased potential. These phenomena are discussed in detail in this paper.     

Interlayer transport of electron in bilayer graphene with phonon-induced lattice distortion in the presence of biased potential

The interlayer transport of electron in bilayer graphene influenced by phonon in the presence of biased potential is investigated using the tight-binding approach. The in-plane optical mode E_2g and out-of-plane optical mode B_1g associated with the applied biased potential are considered to compute and discuss the interlayer transport probability of an electron initially localized on the bottom layer at the Dirac point in the Brillouin zone. Without the biased potential, the interlayer transport probability is equal to 0.5 regardless of the phonon displacement except for a few special cases. Applying a biased potential to the layers, we find that in different phonon mode the function of the transport probability with respect to applied biased potential and phonon displacement is complex and various, but on the whole the transport probability decreases with the increase in the absolute value of the applied biased potential. These phenomena are discussed in detail in this paper.     

垂直矩形窄缝流道内的过冷流动沸腾换热

本文研究了有压模化介质在垂直矩形窄缝流道内的过冷流动沸腾换热，考察了质量流速、断面平均过冷度和饱和压力对沸腾换热系数的影响，与Ｇｕｎｇｏｒ关系式进行比较，流道的换热强化因于在１３～２１之间．