A set of new nucleon coupling constants and the proto neutron star matter

Using a new set of nucleon coupling constants CZ11 the properties of a proto neutron star are examined within the framework of the relativistic mean-field theory for the baryon octet system.It is found that the relative number density of Λ,Ξ-,and Ξ0 for CZ11 are all smaller than those for GL97 and for both CZ11 and GL97,Σ-,Σ0,and Σ+ do not appear.It is also found that the pressure and the maximum mass for CZ11 are all smaller than those for GL97.The maximum mass for CZ11 decreases by approximately 9 percent compared with that for GL97.     

New aspects of isopoly- and heteropolyanions in electrochemistry: chemically modified electrodes,catalysis

Two different aspects of the work carried out in our group on the electrochemistry of oxometalates are briefly reviewed. They concern first the STM observation of H₂W₁₂O₄₀⁶⁻ on graphite electrodes during cyclic voltammetry experiments. These layers are believed to constitute the precursors for the electrochemical activation of electrode surfaces by oxometalates. The second part of the paper is devoted to the electrocatalysis of the reduction of nitrite and nitric oxide by polyoxometalate/polymer systems.     

基于无监督可能模糊学习矢量量化的近红外光谱生菜品种鉴别研究

为解决模糊学习矢量量化(FLVQ)对噪声数据敏感问题,在无监督可能模糊聚类(UPFC)基础上提出一种无监督可能模糊学习矢量量化(UPFLVQ)算法。UPFLVQ用UPFC的隶属度和典型值来更新学习矢量量化网络的学习速率,计算类中心矢量。UPFLVQ 属于无监督机器学习算法,适用于无学习样本情况下的样本分类。研究了UPFLVQ用于近红外光谱生菜品种鉴别的可行性。采用FieldSpec@3型便携式光谱分析仪获取波长范围为350～2 500 nm的三种生菜样本的短波近红外光谱和长波近红外光谱,然后采用主成分分析(PCA)进行近红外光谱的维数压缩,取前三个主成分,累计可信度达97.50%,将2151维的近红外光谱压缩为三维数据。再运行模糊C-均值聚类(FCM)至迭代终止,并以FCM的类中心作为UPFLVQ的初始聚类中心,最后运行UPFLVQ得到隶属度和典型值以实现近红外光谱的生菜品种鉴别。同时,运行UPFC进行近红外光谱的生菜品种鉴别。实验结果表明：UPFLVQ和近红外光谱技术相结合的模型具有检测速度快,鉴别准确率高,对生菜不造成损坏等优点,可实现不同品种生菜的鉴别。UPFLVQ是将UPFC和FLVQ相结合的聚类算法,利用UPFLVQ建立近红外光谱的生菜品种鉴别模型时无需学习样本,适用于线性可分的数据聚类,为快速和无损地鉴别生菜品种提供了一种新的方法。     

Microphase Separation of Star-diblock Copolymer Films: a Dissipative Particle Dynamics Simulation

The microphase-separating behaviors of two types of star-diblock copolymers (A_x)₄(B_y)₄ and (A_xB_y)₄ in thin films are studied using the simulation technique of dissipative particle dynamics. A variety of ordered mesostructures have been observed and the simulated phase diagrams show obvious symmetries for the (A_x)₄(B_y)₄ films and asymmetries for the (A_xB_y)₄ films, besides, it is easier for the (A_x)₄(B_y)₄ than for the (A_xB_y)₄ to carry out microphase separation under the same conditions, which has been recognized in bulk and can be ascribed to the structural difference between the two types of star copolymers. There are some correspondences between the mesostructures formed in the film and those formed in bulk at the same composition fraction. Decreasing the thickness of film and strengthening the A-B repulsion both help the mesostructures enhance the degree of order. Composition fraction dependences of the mean-square radius of gyration in the two types of star copolymer films are almost contrary, which can be attributed to the differences in their respective structures.These findings can provide a guide to designing novel microstructures involving star-diblock copolymers via geometrical confinement.     

大学物理实验中测量不确定度的分析研究

在大学物理实验中,测量不确定度是实验分析的一个重要内容.根据不确定度的分析过程,再结合具体的实验数据,分别对大学物理实验中弹性模量、液体表面张力系数和平凸透镜的曲率半径这3个具有代表性实验的不确定度进行了分析讨论.通过本文的分析,可以为大学物理实验教学和学生处理实验数据提供一个参考,同时能够锻炼学生处理实验数据的能力,也有助于培养学生的意志品质.     

与正弦函数有关的星形函数逆的Toeplitz行列式

Let S*s be the class of normalized functions f defined in the open unit U = {z ∈ C:丨z丨 ＜ 1} such that the quantity zf'(z)/f(z)lies in an eight-shaped region in ...     

Recent advances in catalytic automotive emission control: Passive NO storage at low temperatures

In the practical applications, a high portion of the NO_x is emitted without purification in the cold start period of engine because the selective catalytic reduction (SCR) or NO_x storage and reduction (NSR) catalysts are not warmed up. Passive NO_x absorbers (PNA) were proposed earlier to store the NO_x at low temperatures and release the stored NO_x during warm-up period when the SCR and NSR catalysts downstream are functional, while this concept just attracted great interests recently to meet the extra stringent requirement of governmental emissions regulations. A plant of PNA catalysts, showing different NO adsorption/release characteristics, was disclosed. This review summarizes the recent progress in the development of PNA catalysts. The characteristics of NO adsorption/release on precious metal (i.e., Pt, Pd) loading Al₂O₃ support catalysts, CeO₂ support catalysts, and zeolite support catalysts are summarized and compared.     

Insights into the novel application of Fe-MOFs in ultrasound-assisted heterogeneous Fenton system: Efficiency,kinetics and mechanism

In this work, as a new strategy, ultrasound/H₂O₂/MOF system was firstly applied by environmental-benign Fe-MOFs (MIL-53, MIL-88B and MIL-101) for tetracycline hydrochloride removal. The synthetic Fe-MOFs were characterized by XRD, FTIR, SEM, XPS, N₂ sorption-desorption isotherms and CO-FTIR. MIL-88B demonstrated the best catalytic performance because of its highest amount of Lewis acid sites. Influencing factors, contrast experiment, and corresponding dynamics were carried out to obtain the best experimental conditions and reaction system. Under optimal conditions ([Tetracycline hydrochloride] = 10 mg/L, [MIL-88B] = 0.3 g/L, [H₂O₂] = 44 mM, [ultrasound power] = 60 W, and pH = 5.0), the-first-order kinetic rate constant k was calculated to be 0.226 min⁻¹, higher than the simple combination of the ultrasound system (0.004) and MIL-88B/H₂O₂ system (0.163), indicating the importance of synergistic effect between ultrasound and Fenton reaction. EPR test and quenching experiment proved that ·OH is mainly responsible for tetracycline hydrochloride removal. The major reaction path is the adsorption and decomposition of H₂O₂ by coordinative unsaturated iron sites on Fe-MOF, but it is not the only path. The direct decomposition of H₂O₂ and the cavitation effect caused by ultrasound also contribute to the generation of OH.     

Efficient cleavage of strong hydrogen bonds in sugarcane bagasse by ternary acidic deep eutectic solvent and ultrasonication to facile fabrication of cellulose nanofibers

Cellulose - From the perspective of green chemistry, it is of great significance to produce cellulose nanofibers (CNFs) with more environmentally friendly and sustainable materials. This study...