Environmentally friendly disposable sensors with microfabricated on-chip planar bismuth electrode for in situ heavy metal ions measurement

This paper presents an environmentally friendly disposable heavy metal ion sensor for in situ and online monitoring in the nature and physiological systems. The miniaturized sensor chip consists of a non-toxic microfabricated bismuth (Bi) working electrode that replaces the conventional mercury electrodes, an integrated Ag/AgCl reference electrode, a gold counter electrode, and microfluidic channels. In this work, the electrochemical behavior of the Bi working electrode was characterized in several non-deaerated buffer solutions using cyclic voltammetry. The detection and quantification of Pb (II) and Cd (II) were statically performed using anodic stripping voltammetry inside the microchannels, in the Pb (II) concentration range of 25–400 ppb (R² = 0.991) with limit of detection of 8 ppb for 60 s deposition, and in the Cd (II) concentration range of 28–280 ppb (R² = 0.986) with limit of detection of 9.3 ppb for 90 s deposition. Particularly, the applications of this sensor chip have been reported with the examples of in situ measurement of Cd (II) concentration in soil pore and ground water and online direct measurement of Cd (II) concentration in cell culture media in its native environment.     

A wireless magnetoelastic-sensing device for in situ evaluation of Pseudomonas aeruginosa biofilm formation

A wireless, passive magnetoelastic-sensing device is presented for the in situ, continuous, and real-time evaluation of the formation of Pseudomonas aeruginosa biofilms. The sensor, a polyurethane-coated magnetostrictive ribbon, is placed in a flowing system, and both the resonance frequency and amplitude of the sensor are wirelessly monitored through magnetic field telemetry. The sensor platform appears to be of great utility for the in situ evaluation of biofilms formation.     

A photoluminescence-based quantum semiconductor biosensor for rapid in situ detection of Escherichia coli

This work describes a novel method of detecting Escherichia coli using photoluminescence (PL) emission from III–V quantum semiconductor (QS) devices functionalized with two different antibody-based architectures. The first approach employed self-assembled monolayers of biotinylated polyethylene glycol thiols to immobilize biotinylated antibody via neutravidin. In the second approach, we used QS microstructures coated with a thin layer of Si₃N₄ allowing direct functionalization with E. coli antibodies through hydrofluoric acid etching and glutaraldehyde-based reticulation. Atomic force, optical and fluorescence microscopy measurements were used to assess the immobilization process. Depending on the biosensing architecture, density of the immobilized bacteria was observed in the range of 0.5–0.7 bacteria/100 μm². The detection of E. coli at 10⁴ CFU/ml was achieved within less than 120 min of the bacteria exposure. It is expected that an even better sensitivity threshold could be achieved following further optimization of the method.     

In situ modification of lipid-loaded MCM-41 channels with bovine serum albumin at a planar lipid bilayer for biosensing

An in situ method for modifying a receptor site on mesoporous silica MCM-41 channels in planar lipid bilayers is described, in which bovine serum albumin (BSA) is covalently linked to the MCM-41 channels via head groups of lipids loaded in the nanopores. Prior to receptor modification, lipid-loaded MCM-41 channels were incorporated with lipid bilayers formed at an aperture of a Teflon film. The in situ coupling of BSA to lipid-loaded MCM-41 channels at the lipid bilayer interface was achieved by the sulfhydryl coupling method. The lipid bilayers containing BSA-modified MCM-41 exhibited channel-like currents, which were augmented in a concentration-dependent manner by the addition of anti-BSA at fM level. The in situ modification of lipid-loaded MCM-41 channels with BSA by the amine coupling technique was also investigated. The potential of the present approach for the development of channel-type biosensors is discussed in terms of modifying bilayer interfaces with bioreceptors.     

Flexible H2 sensor fabricated by layer-by-layer self-assembly of thin films of polypyrrole and modified in situ with Pt nanoparticles

A novel flexible H₂ gas sensor was fabricated by the layer-by-layer (LBL) self-assembly of a polypyrrole (PPy) thin film on a polyester (PET) substrate. A Pt-based complex was self-assembled in situ on the as-prepared PPy thin film, which was reduced to form a Pt-PPy thin film. Microstructural observations revealed that Pt nanoparticles formed on the surface of the PPy film. The sensitivity of the PPy thin film was improved by the Pt nanoparticles, providing catalytically active sites for H₂ gas molecules. The interfering gas NH₃ affected the limit of detection (LOD) of a targeted H₂ gas in a real-world binary gas mixture. A plausible H₂ gas sensing mechanism involves catalytic effects of Pt particles and the formation of charge carriers in the PPy thin film. The flexible H₂ gas sensor exhibited a strong sensitivity that was greater than that of sensors that were made of Pd-MWCNTs at room temperature.     

Needle-type in situ water content sensor with polyethersulfone polymer membrane

A needle-type water content sensor with a polyethersulfone (PES, poly(4-phenoxy-co-4-benzensulfone)) polymer membrane is proposed for the low-invasive, direct in situ measurement of plant water content (PWC). When the PWC sensor is inserted into a plant, the electrical impedance of PES is determined by the amount of absorbed water, which indicates the PWC. In situ measurement of PWC was successfully demonstrated for a strawberry plant (Fragaria × ananassa) and the application feasibility of the sensor to in situ PWC measurement for irrigation agriculture was verified.     

Fractional transformation group induced byQR factorization and linear prediction problem

A new fractional transformation group is found which acts transitively on the space of linear predictors for nonstationary processes by using the QR factorization of nonsingular matrices.     

Optimal (N,T)-policy for M/G/1 system with cost structures

In this paper, the optimal (N,T)-policy for M/G/1 system with cost structure is studied. The system operates only intermittently. It is shut down when no customers are present. A fixed set-up cost of K>0 is incurred each time the system is reopened. Also, a holding cost of h>0 per unit time is incurred for each customer present. The (N,T)-policy studied for this system is as follows: the system reactivates as soon as N customers are present or the waiting time of the leading customer reaches a predefined time T (see A.S. Alfa, I. Frigui, Eur. J. Oper. Res. 88 (1996) 599-613; Y.N. Doganata, in: E. Arikan (Ed.), Communication, Control, and Signal Processing, 1990, pp. 1663–1669). Later on, as a comparison, the start of the timer count is relaxed as follows: the system reactivates as soon as N customers are present or the time units after the end of the last busy period reaches a predefined time T. For both cases, the explicit optimal policy (N^*,T^*) for minimizing the long-run average cost per unit time are obtained. As extreme cases, we include the simple optimal policies for N-and T-polices. Several counter-intuitive results are obtained about the optimal T-policies for both types of models.     

F [ x ]-lattice basis reduction algorithm and multisequence synthesis

By means ofF[x]-lattice basis reduction algorithm, a new algorithm is presented for synthesizing minimum length linear feedback shift registers (or minimal polynomials) for the given multiple sequences over a fieldF. Its computational complexity isO(N ²) operations inF whereN is the length of each sequence. A necessary and sufficient condition for the uniqueness of minimal polynomials is given. The set and exact number of all minimal polynomials are also described whenF is a finite field.     

Optimizing Code_Saturne computations on Petascale systems

This paper describes recent developments made to the open source general purpose CFD code Code_Saturne that attempt to address challenges associated with computing at the Petascale. These new features include parallel improved linear solver techniques, parallel I/O methodologies and partitioning tools. The impact of these new features on parallel performance has been analysed for a range of prototype Petascale computing systems as part of the PRACE pan-European initiative.     

Film as Explicador for Hypertext

A few ideas from film theory, most notably Eisenstein's concept of montage, can improve students' understanding of hypertexts and lessen their resistance to open-ended, nonlinear narratives. These structural characteristics, so frustrating to many new readers of hypertext, can also be found in popular and experimental films. In particular, Godfrey Reggio's (1983) documentary Koyaanisqatsi provides a good starting point for merging hypertext and film theory. Koyaanisqatsi not only broke new ground for documentary film; its structure also resembles Landow's model for an axial hypertext. At the same time, techniques pioneered by Landow, Joyce, Guyer, and others involved in creating and critiquing hypertext can be used to examine film. Having students look closely at Koyaanisqatsi's composition allows them to become amateur cinematographers, who now possess software for breaking a film down and examining its composition, montage, transitions, subliminal messages, and motifs – a process that may then be applied to hypertext.     

A Hamiltonian-based solution to the two-block H problem for general plants in H and rational weights

A complete skew-Toeplitz-type solution to the two-block H^∞ problem for infinite-dimensional stable plants with rational weights is derived with a basis-free proof. The solution consists of one Riccati equation with a rank criterion for a transcendental function of a certain Hamiltonian. This gives a natural extension of the well-known formula for the one-block case. An example is given to illustrate the result.     

取定s的严格d-正则随机(3,2s)-SAT问题的可满足临界

3-CNF公式的随机难解实例生成对于揭示3-SAT问题的难解实质和设计满足性测试的有效算法有着重要意义.对于整数k>2和s>0,如果在一个k-CNF公式中每个变量正负出现次数均为s,则称该公式是严格正则（k,2s）-CNF公式.受严格正则（k,2s）-CNF公式的结构特征启发,提出每个变量正负出现次数之差的绝对值均为d的严格d-正则（k,2s）-CNF公式,并使用新提出的SDRRK2S模型生成严格d-正则随机（k,2s）-CNF公式.取定整数5<s<11,模拟实验显示,严格d-正则随机（3,2s）-SAT问题存在SAT-UNSAT相变现象和HARD-EASY相变现象.因此,立足于3-CNF公式的随机难解实例生成,研究了严格d-正则随机（3,2s）-SAT问题在s取定时的可满足临界.通过构造一个特殊随机实验和使用一阶矩方法,得到了严格d-正则随机（3,2s）-SAT问题在s取定时可满足临界值的一个下界.模拟实验结果验证了理论证明所得下界的正确性.     

Rapid differentiation between E. coli and Salmonella Typhimurium using metal oxide sensors integrated with pattern recognition

A rapid method to differentiate between E coli and Salmonella Typhimurium was developed. E. coli and S. Typhimurium were separately grown in super broth and incubated at 37 °C. Super broth without inoculation of E. coli or S. Typhimurium was used as control. Numbers of E. coli and S. Typhimurium were followed using a colony counting method. Identification of the volatile metabolites produced by E. coli and S. Typhimurium was determined using solid-phase microextraction coupled with gas chromatography/mass spectrometry. An electronic nose with 12 non-specific metal oxide sensors was used to monitor the volatile profiles produced by E. coli and S. Typhimurium. Principal component analysis (PCA) and back-propagation neural network (BPNN) were used as pattern recognition tools. PCA was used for data exploration and dimensional reduction. PCA could visualize class separation between sample subgroups. The BPNN was shown to be capable of predicting the number of E. coli and S. Typhimurium. Good prediction was possible as measured by a regression coefficient (R² = 0.96) between true and predicted data. Using metal oxide sensors and pattern recognition techniques, it was possible to discriminate between samples containing E. coli from those containing S. Typhimurium.     

H disturbance attenuation for state delayed systems

In this note, the differential game and dissipation inequality are applied to the disturbance attenuation or H^∞-control for linear systems with delayed state. Firstly, a simple sufficient condition on the existence of a γ-suboptimal H^∞ state feedback controller is given, which is independent of delay, and an observer-based dynamic output feedback solution is presented in terms of Riccati inequalities (or Riccati equations). Secondly, a sufficient condition on the existence of a delay-dependent state feedback is presented and the criterion is presented by a matrix inequality which can be solved by numerical methods.     

A functional νMOS circuit for implementing cellular-automaton picture-processing devices

This paper proposes a design of cell circuits for implementing cellular-automaton devices that perform morphological picture processing. To produce the complex cell functions required for the morphological processing, we present the idea of using the silicon functional device, ν-MOS FET. We designed sample cell circuits for several morphological processings, and simulated their operation to show the expected cell operation. We also designed a sample cellular-automaton circuit using the proposed cell circuits, and demonstrated in simulation its example processing (noise cleaning and edge extraction in an image). A low dissipation of about 20 μW per cell circuit can be expected at 1 MHz operation; therefore, 10⁵ or more cells that operate in parallel can be integrated into an LSI.     

FEWZ 2.0: A code for hadronic Z production at next-to-next-to-leading order

We introduce an improved version of the simulation code FEWZ (Fully Exclusive W and Z Production) for hadron collider production of lepton pairs through the Drell–Yan process at next-to-next-to-leading order (NNLO) in the strong coupling constant. The program is fully differential in the phase space of leptons and additional hadronic radiation. The new version offers users significantly more options for customization. FEWZ now bins multiple, user-selectable histograms during a single run, and produces parton distribution function (PDF) errors automatically. It also features a significantly improved integration routine, and can take advantage of multiple processor cores locally or on the Condor distributed computing system. We illustrate the new features of FEWZ by presenting numerous phenomenological results for LHC physics. We compare NNLO QCD with initial ATLAS and CMS results, and discuss in detail the effects of detector acceptance on the measurement of angular quantities associated with Z-boson production. We address the issue of technical precision in the presence of severe phase-space cuts.

Program summary

Program title: FEWZCatalogue identifier: AEJP_v1_0Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEJP_v1_0.htmlProgram obtainable from: CPC Program Library, Queen?s University, Belfast, N. IrelandLicensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.htmlNo. of lines in distributed program, including test data, etc.: 6 280 771No. of bytes in distributed program, including test data, etc.: 173 027 645Distribution format: tar.gzProgramming language: Fortran 77, C++, PythonComputer: Mac, PCOperating system: Mac OSX, Unix/LinuxHas the code been vectorized or parallelized?: Yes. User-selectable, 1 to 219RAM: 200 Mbytes for common parton distribution functionsClassification: 11.1External routines: CUBA numerical integration library, numerous parton distribution sets (see text); these are provided with the code.Nature of problem: Determination of the Drell–Yan Z/photon production cross section and decay into leptons, with kinematic distributions of leptons and jets including full spin correlations, at next-to-next-to-leading order in the strong coupling constant.Solution method: Virtual loop integrals are decomposed into master integrals using automated techniques. Singularities are extracted from real radiation terms via sector decomposition, which separates singularities and maps onto suitable phase space variables. Result is convoluted with parton distribution functions. Each piece is numerically integrated over phase space, which allows arbitrary cuts on the observed particles. Each sample point may be binned during numerical integration, providing histograms, and reweighted by parton distribution function error eigenvectors, which provides PDF errors.Restrictions: Output does not correspond to unweighted events, and cannot be interfaced with a shower Monte Carlo.Additional comments: !!!!! The distribution file for this program is over 170 Mbytes and therefore is not delivered directly when download or E-mail is requested. Instead a html file giving details of how the program can be obtained is sent.Running time: One day for total cross sections with 0.1% integration errors assuming typical cuts, up to 1 week for smooth kinematic distributions with sub-percent integration errors for each bin.     

Stabilization and H control of symmetric systems: an explicit solution

In this paper we address the H^∞ control analysis, the output feedback stabilization, and the output feedback H^∞ control synthesis problems for state-space symmetric systems. Using a particular solution of the Bounded Real Lemma for an open-loop symmetric system we obtain an explicit expression to compute the H^∞ norm of the system. For the output feedback stabilization problem we obtain an explicit parametrization of all asymptotically stabilizing control gains of state-space symmetric systems. For the H^∞ control synthesis problem we derive an explicit expression for the optimally achievable closed-loop H^∞ norm and the optimal control gains. Extension to robust and positive real control of such systems are also examined. These results are obtained from the linear matrix inequality formulations of the stabilization and the H^∞ control synthesis problems using simple matrix algebraic tools.     

Duality for nondifferentiable static multiobjective variational problems involving generalized (F, ?)-Convex functions

Using the generalized Schwarz inequality, we establish some weak duality theorems for nondifferentiable static multiobjective variational problems involving generalized (F, )-convex functions. Later in the sequel, we introduce three dual models for the nondifferentiable static multiobjective fractional variational problems and derive weak duality results for such programs.     

Multi-log2N交换网络的性能分析模型及控制算法

高速多平面交换网络解决了其内部冲突问题,但需要相应的路由控制算法的辅助,否则,内部冲突不能彻底解决.这是因为包在输入级路由平面的选择不够恰当,容易导致路由冲突的产生.因此,根据冲突链路集的思想,给出一种Multi-log₂N交换网络的控制算法.该算法控制分组在路由平面间的选择,不仅能够适用于RNB和SNB,还能实现单播和多播的控制,保障Multi-log₂N完全实现无阻塞.另一方面,Multi-log₂N消除了内部的链路冲突,提高了交换速率,但对其交换性能缺乏系统的理论分析.给出一种基于嵌入式马尔可夫链的分析模型,对Multi-log₂N网络中队列的使用及分组在队列中的平均等待时间、平均队长等相关性能指标进行了系统的分析,为基于Multi-log₂N的光交换节点的设计提供了良好的理论依据.