果胶@生物炭-Fe3O4的制备及其对Cu2+的吸附性能

以木屑为原料,高温热解制备生物炭。以聚乙烯醇为粘结剂,采用混合法将生物炭与果胶复合,并负载磁性,经烘干定型制备果胶包覆的磁性生物炭材料（果胶@生物炭-Fe₃O₄）。采用扫描电镜（SEM）、X射线衍射（XRD）及N₂吸附-脱附（BET）等方法对果胶@生物炭-Fe₃O₄进行表征,结合吸附实验分析其对Cu²⁺的吸附特性。结果表明,当生物炭、果胶、Fe₃O₄质量比为5：1：1,溶液pH值为6,吸附24 h,果胶@生物炭-Fe₃O₄对Cu²⁺吸附效果最好;二级动力学方程能较好地描述果胶@生物炭-Fe₃O₄对Cu²⁺的吸附过程,Freundlich模型能较好地拟合其吸附行为;SEM结果显示该材料具有不规则的孔隙结构;XRD分析显示纳米Fe₃O₄是其主要的晶体结构;BET测得其比表面积为25.654 m²·g^-1,平均孔径为20.18 nm。     

聚偏氟乙烯共混改性膜对Zn(Ⅱ)吸附性能的研究

应用热引发聚合和相转移技术,制备了具有离子交换性能的聚偏氟乙烯共混改性膜。采用XPS、SEM和FTIR表征了PVDF共混改性膜的结构和组成,测定了共混改性膜的零电荷点（pHpzc）,分析了共混改性膜对水溶液中Zn（Ⅱ）的吸附性能,研究了PVDF共混改性膜对Zn（Ⅱ）的吸附热力学和吸附动力学。结果表明,动力学吸附过程符合准二级动力学方程,等温吸附过程符合Langmuir模型。吸附过程的平均吸附能为8～16kJ/mol,表明该吸附过程为离子交换反应。热力学参数ΔG^0〈0、ΔH^0〉0、ΔS^0〉0,证实了吸附过程为自发的吸热过程。PVDF共混改性膜经吸附/脱附4次循环后,对水体中Zn（Ⅱ）吸附量大于0.005mg/cm^2,脱附率超过95%。     

Nb,Fe单原子掺杂单层MoSe2电子结构及光学性质的理论研究

文章基于密度泛函理论,研究了本征及Nb,Fe单原子掺杂单层MoSe₂的电子结构及光学性质。计算发现,本征单层MoSe₂和Nb-MoSe₂为直接带隙半导体,Fe-MoSe₂为间接带隙结构;Fe-MoSe₂较本征单层MoSe₂导电性大大提高,实现了由半导体向半金属的过渡。由态密度分析得出了本征及Nb,Fe单原子掺杂单层MoSe₂能量状态主要由Mo 4d,Se 4p轨道电子所贡献的结论,并对各原子掺杂体系轨道电子的能量贡献和掺杂类型做了探讨。此外,还详细分析了费米能级附近的自旋态密度、杂质带、磁性之间的联系。光学性质方面,比较了本征单层MoSe₂与各掺杂体系的复介电常数和光吸收系数,在红外光区Fe-MoSe₂的吸收系数高于本征单层MoSe₂。本征单层MoSe₂的光吸收系数为9.69×10⁴ cm^-1,是区域最大吸收峰。上述研究表明,通过对单层MoSe₂的Nb,Fe掺杂可使电子输运特性得到了增强,为高活性自旋电子和光电子器件设计和研究开辟了新的前景。     

mpg-C3N4/BiVO4异质结光催化剂的制备及其降解复方磺胺甲恶唑的效果研究

采用水热合成法制备了典型的手里剑型钒酸铋晶体（BiVO₄）,利用硬模板法制备了介孔氮化碳材料（mpg-C₃N₄）,运用超声分散的方法将二者复合,制得mpg-C₃N₄/BiVO₄异质结光催化剂。文章考察了其在可见光条件下降解复方磺胺甲恶唑的效果,并探讨了影响降解效果的因素。     

三点弯曲梁法下的铁尾矿砂混凝土断裂行为研究

文章从断裂力学的角度开展对铁尾矿砂混凝土的研究,采用三点弯曲梁法对铁尾矿砂混凝土和河砂混凝土进行断裂试验,测定荷载-裂缝口张开位移(P-CMOD)曲线和荷载-应变(P-ε)曲线,依据混凝土双K模型确定起裂荷载(P_ini)、失稳荷载(P_max)、起裂韧度(Kⁱⁿⁱ_Ic)和失稳韧度(K^un_Ic),并利用扫描电镜对断裂面进行观测。通过比较断裂过程曲线和断裂参数发现,两种混凝土的断裂过程没有明显差异,铁尾矿砂混凝土的P_ini,P_max,Kⁱⁿⁱ_Ic和K^un_Ic均高于河砂混凝土,其中P_ini和Kⁱⁿⁱ_Ic更加明显。扫描电镜结果显示,加入铁尾矿砂能够改善混凝土界面过渡区的微观形貌。     

铁尾矿砂光催化剂的制备及其光催化性能研究

以铁尾矿砂为原料,用NaOH,HNO₃调节pH值,采用熔融-水热两步法制备了铁尾矿砂光催化剂。利用X射线衍射仪、紫外/可见/近红外光谱仪等对铁尾矿砂光催化剂的结构性能进行表征;以罗丹明B溶液为标准降解物,汞灯为光源,探讨在不同pH条件下合成的铁尾矿砂光催化剂的光催化活性。结果表明,铁尾矿砂光催化剂的主要成分为Fe_2.35Si_0.65O₄和NaNO₃,且具有良好的光催化效果;在pH 8.5条件下制备的样品具有多孔结构,光催化性能最强;光照120 min时此样品可降解95.1%的罗丹明B溶液;·O₂-是光催化反应过程中最主要的氧化活性自由基。     

L-丙氨酸改性壳聚糖对Sr~(2+)吸附性能研究

采用L-丙氨酸对壳聚糖进行改性,制备了改性壳聚糖,并研究了改性壳聚糖对水溶液中Sr2+的的吸附性能.结果表明:在吸附时间80 min,吸附温度50℃,吸附剂用量0.1 g,p H值为10时,L-丙氨酸改性壳聚糖对Sr2+吸附的的吸附率可达31.800%,吸附量为11.925 mg/g;L-丙氨酸改性壳聚糖微球对高浓度Sr2+的吸附量最大可以达到30.650 mg·g-1,吸附率最高可达83.3%;等温吸附结果表明,L-丙氨酸改性壳聚糖微球对Sr2+的吸附符合Langmuir等温吸附方程;L-丙氨酸改性壳聚糖对Sr2+的吸附过程与准二级动力学具有较高的相关性.     

应用改性粉煤灰处理含铅废水的研究

对改性粉煤灰处理含铅废水进行了实验研究,结果表明,对铅离子的去除效果优于等量未改性粉煤灰和活性炭。吸附时间、废水的pH值、吸附剂用量、温度以及废水中Pb2＋浓度都能影响改性粉煤灰的吸附效果。最适宜的吸附条件是：在室温,pH=8．0,吸附剂用量为1．0g,Pb2＋含量小于0．005mol／L,吸附15min时,改性粉煤灰对废水中Pb2＋的吸附达到饱和。     

固体电解质型NH3传感器综述

NH₃作为一种常见的大气污染气体,具有高毒性和腐蚀性,因此,开发高灵敏度和高选择性的NH₃传感器对排放源(或环境)进行检测,对于改善环境和安全防护较为重要。文章介绍了几种固体电解质型NH₃传感器的工作原理,并对相关的研究进展进行了总结和归纳,对不同种类敏感材料的特点及其应用进行了详细介绍,同时总结了构建高效三相界面的方法及参比电极对传感器性能的影响。     

改性花生壳生物质活性炭对硝基苯的吸附研究

以磷酸溶液:花生壳质量比为1.5:1的磷酸浸渍花生壳。在300℃～900℃的炭化温度制备生物质活性炭;用自制的活性炭吸附水溶液中的硝基苯。并从磷酸浸渍比、炭化温度、吸附时间、吸附温度、溶液的pH值几方面考查对其吸附的影响。结果表明,磷酸浸渍比为30%、炭化温度为800℃、吸附时间为80～90 min、吸附温度为15℃、溶液pH为6～8时条件下的吸附效果最好。硝基苯的吸附去除率为90.06%、吸附量为45.03 mg.g-1。     

Pepsin nanofilm self-assembly on the positively charged poly (ethylene terephthalate) substrate

Pepsin was assembled on the surface of prepared poly (ethylene terephthalate) (PET-NH₃ ⁺) substrates. The composition and structure of the pepsin/PET-NH₃ ⁺ assembling films in different condition were characterized by X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM).     

Fluorescence Properties of Eu^3＋：Y2SiO5 Single Crystal

Fluorescence properties of Eu^3 :Y2SiO5 have been investigated.Transitions between ^5D and ^7Fwere were studied with transmission spectra,fluorescence spectra,photoluminescence excitation(or absorption) spectra and site selective fluorescence spectra.The X-ray powder diffraction pattern of Eu^3 :Y2SiO5 shows that the crystal belong to monoclinic,and lattice‘s constants a,b,c and β arc obtaned by a simulation with the measured diffraction angles.     

Long-term inhibition of Na+/H+ exchange attenuates cardiac remodeling after myocardial infarction in rats

Objective: In addition to pH regulation, Na⁺/H⁺ exchange (NHE) has been shown to facilitate cell growth and proliferation. However, the effects of long-term inhibition of Na⁺/H⁺ exchange on cardiac structural and functional remodeling post myocardial infarction (MI) are still controversial. The present study was therefore carried out to further investigate the effects of long-term treatment with cariporide, a specific inhibitor of NHE-1, on cardiac remodeling after MI in rats; Methods: Male Wistar rats that underwent coronary ligation were randomly selected for cariporide treatment starting 6 h after induction of MI or no treatment. Treatment was continued up to 6 weeks post MI, after which, the arterial, venous and left ventricular catheters were chronically implanted. Twenty-four h later, after hemodynamic signals were recorded in conscious rats, they were sacrificed and hearts were taken out for morphological examinations; Results: Cariporide treatment decreased the heart weight and heart weight to body weight ratio (bothP<0.05), decreased left ventricular end-diastolic pressure (P<0.001), improved myocardial contractility (dP/dt _max) (P<0.05) and tended to increase the survival of treated rats compared to that of untreated infarct rats; Conclusion: The results of the present study indicate that the long-term inhibition of NHE with cariporide can attenuate cardiac structural remodeling and improve left ventricular dysfunction in infarcted rats, and suggest that Na⁺/H⁺ exchange inhibition could be an effective therapeutic strategy for myocardial infarction-induced heart failure.     

Influence of green tea polyphenols on mitochondrial permeability transition pore and Ca2+ transport

The authors investigated the influence of green tea polyphenols (GTPs) on the liver mitochondria permeability transition pore (PTP) opening through mitochondria swelling and change of mitochondria membrane potential. The data showed that GTPs had obvious protective effect on the Ca²⁺-induced PTP opening in a dose-dependent manner detected by mitochondria swelling. The results were obtained by measuring the change of mitochondria membrane potential through Rh 123. Further experiments were conducted to examine the detailed influence of GTPs on Ca²⁺ import and export of mitochondria. The results showed that GTPs had remarkably inhibitory effect on the Ca²⁺-induced Ca²⁺ import in mitochondria; and that they could accelerate Ca²⁺-release from mitochondria. Our data provide an alternate interpretation of the potent protective function of GTPs on cell against apoptosis.     

Mixedl 2/l 1 control for discrete-time systems via lagrange multiplier theory

The dual formulation of the discrete-time mixedl ₂/l ₁ control design problem was achieved by using the duality theory of Lagrange multipliers. For some special dual mixedl ₂/l ₁ problems, an approximation method for the optimal value is introduced. A suboptimal value of the infinite-dimensional dual problem can be obtained by solving a sequence of truncated problems. The convergence property of the solution scheme is investigated. This paper gives a low approximation method for the primal problem. Project(699085) supported by Zhejiang Provincial Natural Science Foundation of China.     

A SISO mixed<Emphasis Type="Italic">H</Emphasis><Subscript>2</Subscript>/l<Subscript>1</Subscript> optimal control problem and its solution

Study of the SISO mixedH ₂/l₁ problem for discrete time systems showed that there exists a unique optimal solution which can be approximated within any prescribed missing error bound inl ₂ norm with solvable suboptimal solutions and solvable superoptimal solutions. Project supported by the National Natural Science Foundation of China (No. 60174026) and the Scientific Research Foundation for Returned Overseas Chinese Scholars of Zhejiang Province (No. J20020546)