压电式传感器测定蛋白质吸附动力学参数

利用液隔电极型压电式传感器实时监测牛血清白蛋白(BSA)在石英表面吸附过程。基于所提出的吸附动力学模型,估算出BSA在石英表面的吸附速率常数为ka=1.27×103mol-1·L·s-1,脱附速率常数为kd=1.31×10-3s-1,由可逆吸附态向不可逆吸附态的转化速率常数为kf=3.46×10-4s-1。     

染料吸附法测定压电石英晶体表面积

利用液隔电极式压电传感器实时监测阳离子染料吖啶橙在石英表面吸附过程中的质量变化 ,求得吖啶橙在石英表面的吸附平衡常数、吸附速率常数、解吸速率常数分别为 :K =6 .5 9× 10 4mol-1.dm3 、ka =79.5mol-1.dm3 .s-1,kd=0 .0 0 12 2s-1(pH=8.5 )。吸附平衡常数随溶液 pH增加而增加 ,在 pH =8.5时达到最大值而后下降。参照溶液差减法所得吸附等温线 ,估算出压电石英晶体的实际表面积为其几何面积的 3.77倍。     

单[6-脱氧(1,10-癸二硫醇)巯基]β-环糊精分子印迹自组装敏感膜-声表面波传感器研究

利用自组装、分子印迹技术在声表面波传感器延迟线上制备了用于甲氟磷酸异丙酯检测的单[6-脱氧(1,10-癸二硫醇)巯基]β-环糊精分子印迹自组装敏感膜;采用原子力显微镜技术对敏感膜的结构进行了表征,验证了成膜效果;对传感器的检测性能进行了评价,传感器对1.7mg/m,的甲氟磷酸异丙酯的响应频率变化为2 170 Hz,进行五次连续检测的标准差和离散系数分别为0.157 kHz、0.070;吸附动力学研究得到ka=1.017×10 5mol-1·l·s-1、kd=2.434×10-3 s-1、kA=4.178×107mol-1·l.     

蛋白质在硅烷膜表面吸附特性的压电传感监测

在压电石英晶片表面自组装修饰末端为胺基的硅烷膜,该膜在酸性和中性pH条件下带正电荷,可通过静电引力吸附带负电荷的牛血清白蛋白(BSA),吸附过程中的质量变化可通过石英晶片的谐振频率变化实时监测。结果表明:该吸附过程虽然为部分不可逆,但吸附等温线符合Langmuir方程,吸附速率常数为0.0117 L.g-1.s-1,吸附平衡常数为2.87 L.g-1,表观饱和吸附量Γ∞=0.954μg.cm-2。     

亲和型生物传感器对TNF-α/sTNFR-I相互作用的研究

应用亲和型生物传感器—Asys生物传感器实时监测不同浓度的肿瘤坏死因子-α(TNF-α)与可溶性肿瘤坏死因子受体-I(sTNFR-I)的亲和反应过程,并应用FASTfit软件对数据进行分析。结果表明:sTNFR-I以2.25 ng/mm2的密度固定于样品池敏感基片表面,TNF-α可与其发生特异性、浓度依赖性亲和反应,应用FASTfit软件进行数据拟合,并计算其反应的动力学常数,其反应符合二级动力学方程,结合速率常数kass=4.21×104L.mol-1.s-1,解离速率常数kd iss=2.12×10-2s-1,则解离平衡常数kD=5.05×10-7mol.L-1,结合平衡常数kA=1.99×106L.mol-1。应用IAsys传感器可实时监测结合和解离反应过程,操作简便、快速,是研究TNF-α和sTNFR相互作用动力学的有效方法。     

基于扫描D触发器的可逆电路测试综合方法

为了实现可逆逻辑电路的可测性设计,充分利用可逆逻辑电路中存在的输出引脚,提出一种可逆逻辑电路测试综合方法.通过定义可逆逻辑门的可观性值和可控性值的计算方法,对可逆逻辑电路的可测性进行建模;通过插入观察点,制定了可逆组合逻辑电路可测性实现方案;通过对现有的D触发器进行改造并构建全新的扫描D触发器,制定了可逆时序电路的可测性逻辑实现方案;最后分析了扫描D触发器的工作特点,规范了测试步骤,建立一种可逆逻辑电路的测试综合方法.实验结果表明,与现有方法相比,文中方法插入观察点代价平均增加不到1%,但电路的可观性平均能得到24%的改善.     

分子动力学模拟HEWL晶体在不同环境中的动力学行为

简要阐述分子动力学模拟的原理及步骤,介绍研究溶菌酶的一般方法和优缺点。在Ubuntu操作系统环境下,利用Gromacs软件和其自带的Gromos96力场,通过分子动力学模拟(MD)鸡蛋清溶菌酶晶体(chicken egg-whitelysozyme,HEWL)溶液,考察真空、水溶液和加入NaCl 3种不同环境条件对溶菌酶晶体构象动力学行为的影响,发现无论从均方根位移(rmsd)、回旋半径、还是从B因子值的轨迹图分析,HEWL在水溶液特别是加入抗衡离子(Na~+,Cl~-)的水溶液的环境下的结构更稳定、合理,与(protein data bank)数据库的真实情况相符。原因是Cl~-与溶菌酶晶体在界面处发生了吸附现象,局部形成溶菌酶-Cl~-复合物,抑制了蛋白-水合物中水分子在相邻水合位置间的跳跃,从而使单晶体在离子液态中更加稳定。模拟结果表明,在pH值6.5,等电位点13.1,总电荷7.999 6的体系下,影响HEWL的吸附位点为123号残基(色氨酸),对从分子水平上解释HEWL晶体的动力学吸附行为具有重要指导意义。     

数据加密新技术

在计算机日益普及的今天,信息的防范也就愈发显得重要.在此,笔者提出一个数据加密的新算法:利用可逆矩阵对任意文件进行加密.设ANXN是一个任意的可逆矩阵XN是由N个字节组成的N维向量(明文),经加密后得密文为N维向量:YN=ANXNXN,由于ANXN可逆,故明文XN=BNXNYN.在实际操作中,由于YN的每一个分量常常超出一字节所能表示的范围,在此我们以两字节表示,所以加密结果将使文件长度是原来的两倍,这是以空间和时间来换取密码强度,著名的陷门     

乙基纤维素修饰的超高交联吸附树脂对四环素的吸附行为

通过Friedel-Crafts反应和化学修饰反应制备了乙基纤维素修饰的超高交联吸附树脂ECMR,采用傅里叶变换红外光谱和比表面及孔径分析对树脂结构和表面参数进行分析表征。通过静态吸附.脱附、吸附动力学和小柱吸附-脱附实验探讨了ECMR树脂对四环素的吸附行为。结果表明:ECMR树脂的BET比表面积为1083.9m~2/g,微孔面积为885.7 m~2/g。与NDA150相比,ECMR树脂对四环素具有更好的吸附性能,2种树脂对四环素的吸附量均随着温度升高而增加,吸附过程存在着较强的不可逆的化学吸附作用。2种树脂对四环素吸附动力学过程符合准一级方程,颗粒内扩散是吸附过程的主要控制步骤。小柱吸附-脱附结果表明ECMR:树脂对四环素的饱和吸附量较大,Methanol/4%NaOH(V_1/V_2=1/1)的溶液能够很好的使ECMR树脂再生。     

硅酸镧镓晶体微天平测定石蜡膜的吸附特性

硅酸镧镓晶体微天平(LCM)是以硅酸镧镓晶体为压电材料研制的新型压电式传感器,对表面质量负载变化有灵敏的频率响应。在LCM表面浇铸石蜡薄膜,实时监测十二烷基苯磺酸钠在石蜡膜表面吸附过程中的质量变化,结果表明:其吸附过程呈现可逆吸附特征,并可以用Langmu ir等温线和动力学模型进行回归分析,获得吸附/脱附速率常数、平衡常数、饱和吸附量等参数,并讨论了盐浓度的影响。     

Sensing properties of monolayer borophane nanosheet towards alcohol vapors: A first-principles study

The electronic properties of borophane nanosheet and adsorption behavior of three distinct alcohol vapors namely methanol, ethanol and 1-propanol on borophane nanosheet is studied using density functional theory method for the first time. The state-of-the-art provides insights on to the development of new two dimensional materials with the surface passivation on boron nanostructures. The density of states spectrum provides a clear perception on charge transfer upon adsorption of alcohol vapors on borophane nanosheets. The monolayer of borophane band gap widens upon adsorption of alcohol vapors, which can be used for the detection for volatile organic vapors. The adsorption properties of alcohol vapors on borophane base material are analyzed in terms of natural bond orbital, average energy gap variation, adsorption energy and energy gap. The most suitable adsorption sites of methanol, ethanol and 1-propanol molecules on borophane nanosheet are investigated in atomistic level. The adsorption of alcohol molecules on borophane nanosheet is found to be more favorable. The findings suggest that the monolayer borophane nanosheet can be utilized to detect the presence of alcohol vapors in the atmosphere.     

Filtering in discrete-time systems with state and observation noises correlated on a finite time interval

The aim of this note is to give recurrence equations for the state estimate and the error covariance of a linear discrete-time system whose state and observation noises arc correlated on a finite time interval. More precisely, we give the recurrence state estimation equations for the systemx(k + 1) = A (k)x(k) + C(k)w(k)(1)y(k) = B(k)x(k) + upsilon(k), k = 0, 1, 2, ..., (2) under the assumptions that noises w(k) and w(l) are uncorrelated for|k - l| > q, whilew(k)andupsilon(l)are uncorrelated forl - k < -sorl - k > t, whereq, s, tare known nonnegative integers.     

Some Indices of Alphabet Overlap Graph

The undirected de Bruijn graph is often used as the model of communication network for its useful properties,such as short diameter,small maximum vertex degree.In this paper,we consider the alphabet overlap graph G(k,d,s): the vertex set V = {v|v = (v1 ...vk);vi ∈ {1,2,...,d},i = 1,2,...,k};they are distinct and two vertices u = (u1 ...uk) and v = (v1 ...vk) are adjacent if and only if us+i = vi or vs+i = ui (i = 1,2,...,k s).In particular,when s = 1,G(k,d,s) is just an undirected de Bruijn graph.First,we give a formula to calculate the vertex degree of G(k,d,s).Then,we use the corollary of Menger’s theorem to prove that the connectivity of G(k,d,s) is 2ds 2d2s k for s k/2.     

A minimum principle for a class of discrete-time stochastic systems

A minimum principle is obtained for discrete-time stochastic systems described by the stochastic difference equationx_{k+1} = A_{k}x_{k} + phi_{k}(u_{k})+w_{k}where{w_{k}, k = 0, ... ,N - }is la sequence of independent random vector variables. The control action ukis constrained to belong to a compact set Uk, and the setphi_{k}(U_{k}), k = 0,..., N - 1is convex. The system is open-loop.     

A stable state-space realization in the formulation of H∞norm computation

In the two block H^inftyoptimization problem, usually we are given the state-space realizations of the proper rational matricesR_{1}(s)andR_{2}(s)whose poles are all the open right-half plane. Two problems are studied in the note. The first is the evaluation ofphi(s)R_{1}(s)ats = s_{k}, k = 1, 2, ..., n, wherephi(s)is an inner function whose zeros{s_{k}, k = 1, 2, ..., n }are the poles ofR_{1}(s). This evaluation is essential if Chang and Pearson's method is used for computing the optimal H^inftynorm. The problem is solved in state space via the solutions of Lyapunov equations. Neither polynomial matrix manipulations nor numerical pole-zero cancellations are involved in the evaluation. The second problem is to find a stable state-space realization ofS(s) = U(s)R_{2}(s)whereU(s)is an inner matrix. This problem arises in the spectral factorization ofgamma^{2} - R_{2}^{ast}R_{2}. Doyle and Chu had a method for constructing stableS(s)based on a minimal realization ofR_{2}(s). An alternate method is proposed. The alternate method does not require a minimal realization ofR_{2}(s)and only a Lyapunov equation is involved.     

Embedding Long Paths in k-Ary n-Cubes with Faulty Nodes and Links

Let k ges 4 be even and let n ges 2. Consider a faulty k-ary n-cube Q^k _n in which the number of node faults fv and the number of link faults f_e are such that f_v + f_e les 2n-2. We prove that given any two healthy nodes s and e of Q^k _n, there is a path from s to e of length at least kⁿ - 2 f_v -1 (respectively, kⁿ - 2 f_v -2) if the nodes s and e have different (respectively the same) parities (the parity of a node in Q^k _n is the sum modulo 2 of the elements in the n-tuple over {0,1,...,k 1} representing the node). Our result is optimal in the sense that there are pairs of nodes and fault configurations for which these bounds cannot be improved, and it answers questions recently posed by Yang, Tan et al. (2007) and by Fu (2006). Furthermore, we extend known results, obtained by Kim and Park (2000), for the case when n=2.     

GENERALIZED HILBERT OPERATOR AND FEJR-RIESZ TYPE INEQUALITIES ON THE POLYDISC

Let f be a holomorphic function on the unit polydisc Dn,with Taylor expansion f(z) = ∞ |k|=0 akzk ≡∞ (k1+···+kn=0) (ak1,···,kn zk1 1znkn)where k = (k1, , kn) ∈ Z+n. The authors define generalized Hilbert operator on Dn by Hγ,n(f)(z) = ∞ |k|=0 i1,···,in≥0 ai1,···,in n j=1 Γ(γj + kj + 1)Γ(kj + ij + 1) Γ(kj + 1)Γ(kj + ij + γj + 2) zk,where γ∈ Cn, such that R γj > -1, j = 1, 2, , n. An upper bound for the norm of the operator on Hardy spaces Hp(Dn) is found. The authors also present a Fejér-Riesz type inequalit...