Input impedance of a probe-excited semi-infinite rectangularwaveguide with arbitrary multilayered loads: part II-a full-waveanalysis

For pt.I see ibid., vol.43, pt.A, pp.1559-66 (July 1995). Utilizing the dyadic Green's functions (DGF's) derived in Part I of this paper, the input impedance of a coaxial probe located inside a semi-infinite rectangular waveguide has been generally formulated. The electromagnetic DGF's for a rectangular cavity with a dielectric load are also obtained from the general expressions given in Part I. Using the full-wave analysis, a dielectric-loaded rectangular cavity is further considered and the input impedance is specified. To improve the computational accuracy, an alternative form of electric DGF's of the second kind is developed and expressed in terms of the guided-wave eigenvalues for the rectangular loaded cavity. The probe-input reactance and the phase of the reflection coefficients are computed using the conventional form of electric DGF and the alternative form of magnetic DGF. Data are obtained from experiments performed on a dielectric-loaded cavity and compared with the numerical results. Agreement of the theoretical and experimental results confirms the applicability of the theoretical analysis given in this paper     

Comparing Antioxidant Effectiveness of Natural and Synthetic Free Radical Scavengers in Thermally-Oxidized Lard using DPPH Method

ABSTRACT: Antioxidant effectiveness of free radical scavengers (FRSs) of α-tocopherol, sesamol, butylated hydroxytoluene (BHT), and tert-butylhydroquinone (TBHQ) were evaluated in thermally-oxidized lard using methods of 2,2-diphenyl-1-picrylhydrazyl (DPPH), conjugated dienoic acid (CDA), and p-anisidine value (p-AV). Absorbance of DPPH with lard containing 2.5 μmol/g FRSs were low before oxidation while those with control lard was high due to the hydrogen atom donating ability of FRSs. During oxidation, DPPH absorbance with lard containing FRSs increased differently up to the certain point depending on the types of FRSs. DPPH absorbance of lard without FRSs started to decrease upon oxidation, which indicates that free radical scavenging compounds were generated from oxidized lipids. Results of CDA and p-AV showed that the highest antioxidant capacity was in the order of TBHQ = sesamol, BHT, and α-tocopherol. Antioxidant effectiveness of FRS should consider the hydrogen atom donating rates of FRS, the reactivity and stability of FRS at treatment temperature, and characteristics of radicals from FRSs, which may be predicted by the results of DPPH method.     

Effective Laser Sealing Enabled by Glass Thick Films Containing Carbon Black/Carbon Nanotubes

An effective way of providing complete sealing of glass using an 810 nm diode laser was investigated for longer lifetime of glass panel‐based devices. Small amounts (<5 wt%) of laser‐absorbing materials such as carbon black (CB) or carbon nanotubes (CNT) were added to a bismuth zinc borate glass paste for instantaneous adhesion between glass substrates without interfacial cracks or severe pores. A higher laser power was required for a lower content of carbon for the laser‐assisted sealing of glass. As optimal compositions, the addition of 1.0 wt% CB or 0.5 wt% CNT led to complete densification of glass with higher optical transmittance. Higher absorption coefficients calculated in the CNT case, e.g., ~536.4 cm^?1 for the 0.5 wt% CNT sample compared to ~277.6 cm^?1 for the 0.5 wt% CB sample, are believed to be responsible for the effective sealing even with a lower content of CNT.     

Structurally Controlled Cellular Architectures for High‐Performance Ultra‐Lightweight Materials

The design and synthesis of cellular structured materials are of both scientific and technological importance since they can impart remarkably improved material properties such as low density, high mechanical strength, and adjustable surface functionality compared to their bulk counterparts. Although reducing the density of porous structures would generally result in reductions in mechanical properties, this challenge can be addressed by introducing a structural hierarchy and using mechanically reinforced constituent materials. Thus, precise control over several design factors in structuring, including the type of constituent, symmetry of architectures, and dimension of the unit cells, is extremely important for maximizing the targeted performance. The feasibility of lightweight materials for advanced applications is broadly explored due to recent advances in synthetic approaches for different types of cellular architectures. Here, an overview of the development of lightweight cellular materials according to the structural interconnectivity and randomness of the internal pores is provided. Starting from a fundamental study on how material density is associated with mechanical performance, the resulting structural and mechanical properties of cellular materials are investigated for potential applications such as energy/mass absorption and electrical and thermal management. Finally, current challenges and perspectives on high‐performance ultra‐lightweight materials potentially implementable by well‐controlled cellular architectures are discussed.     

Advanced Soft Materials,Sensor Integrations,and Applications of Wearable Flexible Hybrid Electronics in Healthcare,Energy, and Environment

Recent advances in soft materials and system integration technologies have provided a unique opportunity to design various types of wearable flexible hybrid electronics (WFHE) for advanced human healthcare and human–machine interfaces. The hybrid integration of soft and biocompatible materials with miniaturized wireless wearable systems is undoubtedly an attractive prospect in the sense that the successful device performance requires high degrees of mechanical flexibility, sensing capability, and user-friendly simplicity. Here, the most up-to-date materials, sensors, and system-packaging technologies to develop advanced WFHE are provided. Details of mechanical, electrical, physicochemical, and biocompatible properties are discussed with integrated sensor applications in healthcare, energy, and environment. In addition, limitations of the current materials are discussed, as well as key challenges and the future direction of WFHE. Collectively, an all-inclusive review of the newly developed WFHE along with a summary of imperative requirements of material properties, sensor capabilities, electronics performance, and skin integrations is provided.     

Tracking Drug‐Induced Epithelial–Mesenchymal Transition in Breast Cancer by a Microfluidic Surface‐Enhanced Raman Spectroscopy Immunoassay

Epithelial–mesenchymal transition (EMT) is a primary mechanism for cancer metastasis. Detecting the activation of EMT can potentially convey signs of metastasis to guide treatment management and improve patient survival. One of the classic signatures of EMT is characterized by dynamic changes in cellular expression levels of E‐cadherin and N‐cadherin, whose soluble active fragments have recently been reported to be biomarkers for cancer diagnosis and prognosis. Herein, a microfluidic immunoassay (termed “SERS immunoassay”) based on sensitive and simultaneous detection of soluble E‐cadherin (sE‐cadherin) and soluble N‐cadherin (sN‐cadherin) for EMT monitoring in patients' plasma is presented. The SERS immunoassay integrates in situ nanomixing and surface‐enhanced Raman scattering readout to enable accurate detection of sE‐cadherin and sN‐cadherin from as low as 10 cells mL^?1. This assay enables tracking of a concurrent decrease in sE‐cadherin and increase in sN‐cadherin in breast cancer cells undergoing drug‐induced mesenchymal transformation. The clinical potential of the SERS immunoassay is further demonstrated by successful detection of sE‐cadherin and sN‐cadherin in metastatic stage IV breast cancer patient plasma samples. The SERS immunoassay can potentially sense the activation of EMT to provide early indications of cancer invasions or metastasis.     

Path and Oracle Discovery Protocol for Centralized Bandwidth Reservation Mechanisms

The introduction of Differential Service architecture has initiated interests in centralized bandwidth reservation via an oracle with each network domain defining its own oracle. The centralized bandwidth reservation mechanism requires knowledge of network topology and reservation paths in the domain to control access to premium services as well as log usage. We propose a new reactive protocol, Path and Oracle Discovery Protocol (PODP), to facilitate the management of networks with centralized bandwidth reservations. This protocol discovers the routers traversed by the network connection request and the respective domain oracle. PODP is able to respond to network path changes at minimum network overhead and storage requirements compared to other methods. A prototype router and oracle supporting the PODP has been successfully developed and tested across multiple domains.     

Elastic mesh technique for 3D BIM simulation with an application to underwater explosion bubble dynamics

The proposed elastic mesh technique (EMT) is a mesh regulation technique, which is based on the assumption that the segments of a mesh are elastic. EMT can be employed in conjunction with the boundary integral method (BIM) for the simulation of three-dimension bubble dynamics in which problems relating to severe mesh distortion as the bubble evolves are a common occurrence. With EMT, the mesh is advanced not by the material velocity, but the optimum shift velocity obtained by minimizing the total elastic energy stored in every segment of the mesh at each time step. In doing so, the prohibitively small time stepping associated with small meshes without EMT in order to maintain numerical stability is mitigated to a large extent. An important feature is that the EMT scheme accords the user the flexibility to implement a non-uniform optimum constitutive relation governing the elastic behavior of mesh segment and which can be further varied with time. Tests were performed for an underwater explosion bubble exhibiting the dynamics of strong jet development with and without EMT for comparison, and the consideration of incorporating EMT as a hybrid system serving as an alternative to the required mesh refinement which is computationally intensive. A full three-dimension simulation of explosion bubble(s) and in the presence of the free surface were further carried out to elucidate the associated flow physics.     

A New Lower Bound on the Maximum Number of Satisfied Clauses in Max-SAT and Its Algorithmic Applications

A pair of unit clauses is called conflicting if it is of the form (x), $(\bar{x})$ . A CNF formula is unit-conflict free (UCF) if it contains no pair of conflicting unit clauses. Lieberherr and Specker (J. ACM 28:411?C421, 1981) showed that for each UCF CNF formula with m clauses we can simultaneously satisfy at least $\hat{ \varphi } m$ clauses, where $\hat{ \varphi }=(\sqrt{5}-1)/2$ . We improve the Lieberherr-Specker bound by showing that for each UCF CNF formula F with m clauses we can find, in polynomial time, a?subformula F?? with m?? clauses such that we can simultaneously satisfy at least $\hat{ \varphi } m+(1-\hat{ \varphi })m'+(2-3\hat {\varphi })n''/2$ clauses (in F), where n?? is the number of variables in F which are not in F??. We consider two parameterized versions of MAX-SAT, where the parameter is the number of satisfied clauses above the bounds m/2 and $m(\sqrt{5}-1)/2$ . The former bound is tight for general formulas, and the later is tight for UCF formulas. Mahajan and Raman (J. Algorithms 31:335?C354, 1999) showed that every instance of the first parameterized problem can be transformed, in polynomial time, into an equivalent one with at most 6k+3 variables and 10k clauses. We improve this to 4k variables and $(2\sqrt{5}+4)k$ clauses. Mahajan and Raman conjectured that the second parameterized problem is fixed-parameter tractable (FPT). We show that the problem is indeed FPT by describing a polynomial-time algorithm that transforms any problem instance into an equivalent one with at most $(7+3\sqrt{5})k$ variables. Our results are obtained using our improvement of the Lieberherr-Specker bound above.     

Parameterized Complexity Results for General Factors in Bipartite Graphs with an Application to Constraint Programming

The NP-hard general factor problem asks, given a graph and for each vertex a list of integers, whether the graph has a spanning subgraph where each vertex has a degree that belongs to its assigned list. The problem remains NP-hard even if the given graph is bipartite with partition U?V, and each vertex in?U is assigned the list {1}; this subproblem appears in the context of constraint programming as the consistency problem for the extended global cardinality constraint. We show that this subproblem is fixed-parameter tractable when parameterized by the size of the second partite set?V. More generally, we show that the general factor problem for bipartite graphs, parameterized by |V|, is fixed-parameter tractable as long as all vertices in?U are assigned lists of length?1, but becomes $\text {\normalfont W[1]}$ -hard if vertices in?U are assigned lists of length at most?2. We establish fixed-parameter tractability by reducing the problem instance to a bounded number of acyclic instances, each of which can be solved in polynomial time by dynamic programming.