Cascades with coupled map lattices in preferential attachment community networks

In this paper, cascading failure is studied by coupled map lattice （CML） methods in preferential attachment community networks. It is found that external perturbation R is increasing with modularity Q growing by simulation. In particular, the large modularity Q can hold off the cascading failure dynamic process in community networks. Furthermore, different attack strategies also greatly affect the cascading failure dynamic process. It is particularly significant to control cascading failure process in real community networks.     

Topological Effects on the Performance of Transportation Networks

We investigate the influence of the network topology on the performance （characterized by the total system cost and maximal tratffic volume） of transportation networks, where the weights are not static （constant）, but dynamic （a function of the flow on the link）. Four classes of networks are used in the simulation, including regular networks, random networks, small-world networks and scale-free networks. The initial simulation results show that topologies play important roles on the performance of transportation networks, and random networks have better performance than other networks. Also, we find that there are distinct difference of the link flow distribution for various networks in both the distribution function form and the span between the minimum and the maximum of the link flow, explaining the difference of the performance among distinct networks. These findings will be useful in network design problems of transportation systems.     

Crystal Structure and Characterization of a Binuclear Cd(II) Quaternary Coordination Complex [Cd2(phen)2Q2(BP)]n (phen = 1,10-Phenanthroline, BP = Biphenyl-4,4--dicarboxylic acid, Q = 8-Hydroxyquinoline Anion)

The structure of a binuclear cadmium(II) quaternary complex, [Cd2(phen)2- Q2(BP)]n 1 (phen = 1,10-phenanthroline, BP = biphenyl-4,4--dicarboxylic acid, Q = 8-hydroxy- quinoline-anion), has been determined by X-ray crystallography and characterized by elemental analysis, IR spectrum and thermogravimetric analysis.It crystallizes in the monoclinic system, space group P21/n with a = 13.1906(18), b = 10.9623(15), c = 16.947(2) -, β = 111.3430(10)°, V = 2282.5(5) -3, Z = 4, Mr = 556.85, Dc = 1.620 g/cm3, F(000) = 1116, μ = 0.994 mm-1 and S = 1.056.In the structure, 1D chains are connected via biphenyl-4,4--dicarboxylic acid, 8-hydroxy quinoline anion and binuclear cadmium atoms into an infinite 1-D molecular chain architecture.Via aryl ring π-π stacking interactions a supramolecular structure is formed in 1.     

气体团簇离子束两步能量修形法的平坦化效应

本文提出采用气体团簇离子束的两步能量修形法来改善4H-SiC(1000)晶片表面形貌.先用15 keV的高能Ar团簇离子进行整体修形,再用5 keV的低能团簇离子优化表面.结果表明,在相同的团簇离子剂量下,与单一15 keV的高能团簇处理相比,两步法修形后的表面具有更低的均方根粗糙度,两者分别为1.05 nm和0.78 nm.本文还以原子级平坦表面为研究对象,揭示了载能团簇引起的半球形离子损伤(弧坑)与团簇能量的关系,及两步能量修形法在弧坑修复中的优势.在原子力显微镜表征的基础上,引入了二维功率谱密度函数,以直观全面地给出材料的表面形貌特征及其随波长(频率)的分布.结果表明,经任何能量的团簇离子轰击的表面,在0.05—0.20μm波长范围内,团簇轰击都能有效地降低粗糙度,而在0.02—0.05μm范围内,则出现了粗化效应,这是由于形成了半球形离子损伤,但第二步更低能量的团簇离子处理可以削弱这种粗化效应.     

同位素内标超高效液相色谱-串联质谱法检测大鼠血清中丙烯酰胺和环氧丙酰胺

建立了检测大鼠血清中丙烯酰胺和环氧丙酰胺的超高效液相色谱-串联质谱法(UPLC-MS/MS).血清样品中加入乙腈沉淀蛋白质,超高速离心取上清液,离心浓缩后,采用ACQUITY UPLC T3 C18色谱柱(50 mm×2.1 mm, 1.7 μm),以0.1%甲酸溶液和甲醇为流动相进行梯度洗脱,经UPLC分离,电喷雾离子化四级杆串联质谱以正离子多反应监测方式(MRM)检测,用同位素内标法定量.丙烯酰胺和环氧丙酰胺在0.5～20.0 mg/L浓度范围内线性良好,相关系数r均大于0.999;检出限均为0.1 mg/L;在3个浓度水平(2.0, 8.0, 和15.0 mg/L)进行添加实验,样品的加标回收率分别为98.0%～108.3%和99.6%～106.7%;日内精密度(RSD)为0.54%～5.8%和1.1%～5.8%;每个样品测试时间仅为6 min.本方法测定大鼠血清中的丙烯酰胺和环氧丙酰胺操作简单快速, 重现性好, 灵敏度高.     

Theoretical Study on the Reaction of FeS+(6∑+,4Ф)with COS in the Gas Phase

The possible reaction mechanisms of FeST(6∑+and 4Ф states)with COS in the gas phase have been studied by using density functional theory at the B3LYP/TZVP and B3LYP/6-311+G*levels:the O/S exchange reaction(FeS++COS=FeO++CS2),O-transfer reaction(FeS++COS=FeSO++CS)and S-transfer reaction(FeS++COS=FeS2++CO).The calculation results show that the large barriers(205.7 and 310.1 kJ/mol)and the small probability of forming the preceding intermediate indicate a much lower efficiency of the O/S exchange and the O-transfer reactions and their corresponding products may not be observed experimentally.FeS2+,the product of S-transfer reaction,is predicted to be the main product.But the reactivity of the 6∑+ground state of FeS+toward COS is lower than the earlier transition metal sulfide cations MS+(M=Sc,Ti and V),although it has more reaction channels and different mechanisms.     

Gemini表面活性剂烷烃尾链在吸附和聚集过程中的疏水协同效应(英文)

以表面张力法测定了系列Gemini表面活性剂m-6-m以及对应单体表面活性剂CmTABr的临界胶束浓度(cmc)和降低水表面张力20mN·m-1需要的浓度(pC20).比较这些参数表明m-6-m胶束化和在界面吸附的能力均强于CmTABr,这被归结为Gemini表面活性剂烷烃尾链间的疏水协同效应.与不对称Gemini表面活性剂12-6-m比较,对称的Gemini结构更有利于表面活性剂的聚集和吸附.     

不同产地珠子参中微量元素含量分析

分析不同产地珠子参中微量元素的含量变化情况。应用电感耦合等离子体-原子发射光谱法（ICP-AES）测定不同产地珠子参中Ca、Cr、Cu、Fe、Ga、Li、Mg、Mn、Ni、Sn、Sr、Ti、Tl、V、Zn、Pb 16种微量元素的含量。结果表明,不同产地珠子参中各微量元素含量有所差异,陕西宁强产珠子参中Ca、Mg、Mn、Zn、Cu等含量高于其他产地。珠子参中微量元素的含量与产地的土壤、水质等有关。     

近红外光谱法预测粗皮桉木材气干密度的影响因素分析

采用近红外光谱分析技术,对粗皮桉木材气干密度校正模型的影响因素进行比较研究.使用直接测量法测量了粗皮桉木材的气干密度,并用近红外光谱仪采集试样的近红外漫反射光谱,对不同切面、厚度、含水率和粗糙度的粗皮桉木材试样的原始光谱进行二阶导数预处理并选择一定光谱段建立回归模型.以50～140个试样作为校正集建立木材气干密度的偏最...     

一种双正则项全变差高光谱图像去噪算法

受传感器特性影响,高光谱图像中的噪声在各个维度都有体现。噪声的存在降低了高光谱图像中信息的有效性,在进行地物分类前必须采用适当的算法对噪声予以去除。文章针对高光谱图像的噪声特性,提出了一种基于全变差的高光谱图像去噪算法。该算法将经典二维图像全变差去噪模型推广至三维形式,提出了采用双正则项及相应的调整参数的目标函数,在三维空间中完成新目标函数的离散化,并采用基于优化-最小化算法的迭代方法对目标函数进行优化与求解。对星载Hyperion成像光谱仪数据的实验表明,适当的设置调整参数,该方法可很好地提高高光谱图像的各波段信噪比、平滑光谱曲线并保留细节特征,其去噪效果优于经典的MNF去噪算法及Savitzky-Golay滤波方法。