A dual-function chemosensor based on coumarin for fluorescent turn-on recognition of Hg2+ and colorimetric detection of Cu2+ in aqueous media

A novel coumarin derivative CTT was synthesized via the condensation of 7-(N,N-diethylamino) coumarin-3-aldehyde with 5-amino-1,3,4-thiadiazole-2-thiol and its structure was characterized using infrared spectroscopy (IR), ¹H NMR, mass spectrometry (MS) techniques, and elemental analysis. The recognition properties of CTT with metal ions were investigated in CH₃CN–H₂O (v/v = 1/1) solution using UV–vis absorption and fluorescence emission spectrum method. The results showed that CTT could monitor Cu²⁺ and Hg²⁺ simultaneously as a dual-function chemosensor in CH₃CN–H₂O (v/v = 1/1). CTT could be used to detect Cu²⁺ colorimetrically; when using CTT, a color change from yellowish-brown to yellowish-green could be readily observed by the naked eye. CTT showed turn-on fluorescent recognition of Hg²⁺, the fluorescence enhancement was attributed to the inhibited C=N isomerization and the obstructed excited state intramolecular proton transfer (ESIPT) of CTT. The recognition mechanism of CTT for Cu²⁺ and Hg²⁺ was studied by experiments and theoretical calculations, respectively. Therefore, CTT has the ability to be a “single chemosensor for dual targets.”     

一种耦合斯特林制冷效应的复合式磁制冷循环的数值模拟

介绍了一种斯特林回热式制冷效应和主动式磁制冷效应耦合的新型制冷循环。循环采用的回热填料钆既是磁制冷循环的磁热材料又是斯特林制冷的回热材料。通过斯特林回热式制冷循环和磁制冷效应的正面耦合叠加获得更优良的制冷效果。同时介绍了一种磁制冷回热器的数值计算模型,本模型是基于控制容积法计算的一维交变流动模型,并对常规回热器内填料能量控制方程进行了修正,考虑了磁性材料磁热效应的影响,添加内热源项。论文计算分析了系统相位角、压力和频率的变化对制冷性能的影响。文中给出的部分模拟结果对后续实验台的改造有一定的借鉴指导作用。     

The heat and moisture transfer balance theory of garment simulation

To establish the human body model to analyze the heat and moisture transfer on body surface, a new explicit definition of rational L-recursion surface is given and the L-recursion surfaces, in Grassmann spaces, are constructed by using blossom method of the homogeneous normal pyramid form. Based on our human body model, the balance theory of garment simulation, the heat and moisture transfer balance equations, called ICAD-balance equations are obtained. The balance theory of garment simulation integrally studies the complex system of human body-fabric-environment. At the same time, the method of obtaining the heat and moisture transfer balance equations is also based on the mass conservation law, the energy conservation law and the Fish law of capillarity. A finite volume method is employed to solve the ICAD-balance equations.     

A finite-element mechanical contact model based on Mindlin-Reissner shell theory for a three-dimensional human body and garment

Efficient numerical methods for describing a garment’s mechanical behavior during wear have been identified as the key technology for garment simulation. This paper presents a finite-element mechanical contact model based on Mindlin-Reissner shell theory for a three-dimensional human body and garment. In this model, the human body and the garment are meshed as basic contact cells, these contact cells between the human body and the garment are defined as the contact pair to describe the contact relationship, and the mathematical formulation of the finite-element model is defined to describe the strain-stress performance of the three-dimensional human body and garment system. By using the solution given by the computer code and the programs specifically developed, the calculations of the mechanics in the basic cells of the human body and the garment have been able to be carried out. The simulation results show that the model of rationality, a good simulation results and simulation efficiency.     

On the gluing formula for the analytic torsion

In this paper, we derive the Cheeger–Müller/Bismut–Zhang theorem for manifolds with boundary and the gluing formula for the analytic torsion of flat vector bundles in full generality, i.e., we do not assume that the Hermitian metric on the flat vector bundle is flat nor that the Riemannian metric has product structure near the boundary.     

A linearized difference scheme for semilinear parabolic equations with nonlinear absorbing boundary conditions

A novel three level linearized difference scheme is proposed for the semilinear parabolic equation with nonlinear absorbing boundary conditions. The solution of this problem will blow up in finite time. Hence this difference scheme is coupled with an adaptive time step size, i.e., when the solution tends to infinity, the time step size will be smaller and smaller. Furthermore, the solvability, stability and convergence of the difference scheme are proved by the energy method. Numerical experiments are also given to demonstrate the theoretical second order convergence both in time and in space in L_∞-norm.     

Synthesis and Tumor Cytotoxicity of Novel N-Substituted Glucosamine-bearing Oleanolic Acid Derivatives

Eleven novel triterpenoid saponins,N-substituted-β-D-glucosaminide derivatives of oleanolic acid,were designed and synthesized via a stepwise glycosylation strategy.These compounds were evaluated for in vitro cytotoxic activity against six different tumor cell lines.Most of the compounds inhibited the growth of,at least,one tumor cell line effectively at micromolar concentrations.Preliminary structure-activity relationships（SARs） indicate that acylation of the nitrogen of the glucosamine-bearing triterpenoid saponins affords the compounds that are highly cytotoxic towards specific tumor cell lines.     

Keggin型铬取代杂多阴离子/D301R可见光催化性能

将Keggin型铬取代磷钨杂多阴离子PW11O39Cr(Ⅲ)(H2O)4-(PW11Cr)负载于弱碱性阴离子交换树脂D301R表面,制备了固体光催化剂PW11Cr/D301R,并以模型污染物罗丹明B(RhB)的降解为探针评估了该催化剂的可见光催化活性,讨论了光催化反应机理,同时考察了催化剂剂量、溶液pH值和溶液中常见离子对RhB可见光催化降解反应的影响以及催化剂的稳定性。 实验结果表明,当PW11Cr/D301R的剂量为100 mg时,10 μmol/L RhB水溶液暴露在200 W金卤灯下进行照射,RhB完全降解所需的时间仅为30 min,比PW11Cr均相体系缩短了3倍;反应180 min总有机碳(TOC)去除率约为84%。 催化剂剂量、溶液pH值和溶液中存在的Cl-、SO2-4和PO3-4对RhB光催化降解反应的速率均有一定影响。 催化剂循环实验显示经循环使用7次后催化剂的活性几乎没有损失。     

裂殖壶菌对7种抗生素的敏感性

实验室条件下研究了Zeocin、两性霉素B(Amphotericin B)、G418、氯霉素(Cm)、氨苄青霉素(Amp)、卡那霉素(Km)、链霉素(Str)7种基因工程常用抗生素对裂殖壶菌(Schizochytrium limacinum)生长的影响。结果表明:S.limacinum对Zeocin最为敏感,在2.5～4mg.L-1 Zeocin中成活率降至2.10%～2.79%(P<0.01);对两性霉素B、G418、Cm较敏感,在14～20mg.L-1两性霉素B中的成活率降至5%以下(P<0.01),在140mg.L-1G418中的成活率为2.08%(P<0.01),在25.5～68mg.L-1 Cm中成活率为13%左右(P<0.05);对Amp,Km,Str不敏感,50～300mg.L-1的Amp,Km,Str不能抑制其生长,成活率仍在80%以上(P>0.05).     

Construction of differentiable transformations

Construction of invertible transformations using differential equations is an interesting and challenging mathematical problem with important applications. We briefly review the existing method by means of harmonic maps in 2D and propose a method of constructing differentiable, invertible transformations between domains in two and three dimensions. Preliminary numerical results demonstrate the effectiveness of the method.