Showing papers by "National Tsing Hua University published in 2006"
TL;DR: Under linear, Gaussian assumptions on the target dynamics and birth process, the posterior intensity at any time step is a Gaussian mixture and closed-form recursions for propagating the means, covariances, and weights of the constituent Gaussian components of the posteriorintensity are derived.
Abstract: A new recursive algorithm is proposed for jointly estimating the time-varying number of targets and their states from a sequence of observation sets in the presence of data association uncertainty, detection uncertainty, noise, and false alarms. The approach involves modelling the respective collections of targets and measurements as random finite sets and applying the probability hypothesis density (PHD) recursion to propagate the posterior intensity, which is a first-order statistic of the random finite set of targets, in time. At present, there is no closed-form solution to the PHD recursion. This paper shows that under linear, Gaussian assumptions on the target dynamics and birth process, the posterior intensity at any time step is a Gaussian mixture. More importantly, closed-form recursions for propagating the means, covariances, and weights of the constituent Gaussian components of the posterior intensity are derived. The proposed algorithm combines these recursions with a strategy for managing the number of Gaussian components to increase efficiency. This algorithm is extended to accommodate mildly nonlinear target dynamics using approximation strategies from the extended and unscented Kalman filters
1,805 citations
TL;DR: This paper presents a fuzzy c-means (FCM) algorithm that incorporates spatial information into the membership function for clustering and yields regions more homogeneous than those of other methods.
1,296 citations
TL;DR: In this paper, the authors consider a large number of alliages a haute entropie (AHE) which are characterized by a large amount of microstructures and fragiles, e.g., nanocristallines and meme amorphes.
Abstract: Progres recents dans les alliages a haute entropie. La trentaine de systemes d'alliages actuellement d'utilisation courante sont typiquement bases sur un ou, au plus, deux elements. On considerait que des alliages constitues d'un plus grand nombre d'elements principaux formeraient des microstructures compliquees et fragiles, et la recherche sur de tels alliages multielementaires a donc ete tres limitee. Cependant, en 1995, Yeh a suggere que les systemes d'alliages formes d'au moins cinq elements metalliques possedaient des entropies de melange elevees et favoriseraient donc la formation de solutions solides multielementaires, par opposition aux supposees structures complexes formees de nombreux composes intermetalliques. Les travaux effectues au cours de la derniere decennie sur de tels alliages multielementaires, denommes de facon appropriee « alliages a haute entropie » (AHE), ont en effet montre que ces derniers formaient des phases simples a structures nanocristallines et meme amorphes. Outre l'effet de haute entropie, ces caracteristiques structurales ont ete attribuees a l'existence dans ces melanges multielementaires de fortes distorsions de reseau et d'une diffusion ralentie. En fonction de leur composition et du procede d'elaboration, il s'est avere que les AHE presentaient un large spectre de microstructures et de proprietes. Les proprietes superieures de certains AHE par rapport aux alliages classiques, ainsi que le nombre enorme de combinaisons possibles susceptibles de conduire a des phenomenes nouveaux et a des applications fonctionnelles, font que ces AHE presentent un grand interet non seulement du point de vue de la recherche mais aussi pour de nombreuses applications industrielles. Dans cette perspective, cet article passe en revue les progres recents dans les AHE et les orientations futures.
1,288 citations
TL;DR: This work provides a new probabilistic derivation for any incidence-based index that is symmetric and homogeneous and proposes estimators that adjust for the effect of unseen shared species on the authors' abundance-based indices.
Abstract: A wide variety of similarity indices for comparing two assemblages based on species incidence (i.e., presence/absence) data have been proposed in the literature. These indices are generally based on three simple incidence counts: the number of species shared by two assemblages and the number of species unique to each of them. We provide a new probabilistic derivation for any incidence-based index that is symmetric (i.e., the index is not affected by the identity ordering of the two assemblages) and homogeneous (i.e., the index is unchanged if all counts are multiplied by a constant). The probabilistic approach is further extended to formulate abundance-based indices. Thus any symmetric and homogeneous incidence index can be easily modified to an abundance-type version. Applying the Laplace approximation formulas, we propose estimators that adjust for the effect of unseen shared species on our abundance-based indices. Simulation results show that the adjusted estimators significantly reduce the biases of the corresponding unadjusted ones when a substantial fraction of species is missing from samples. Data on successional vegetation in six tropical forests are used for illustration. Advantages and disadvantages of some commonly applied indices are briefly discussed.
550 citations
TL;DR: In this article, the AlxCoCrCuFeNi alloys with different aluminum contents prepared by arc melting were investigated on their adhesive wear behaviors and the wear mechanism changes from delamination wear to oxidative wear.
532 citations
TL;DR: In this paper, four LEP collaborations, ALEPH, DELPHI, L3 and OPAL, have searched for the neutral Higgs bosons which are predicted by the minimal supersymmetric standard model (MSSM).
Abstract: The four LEP collaborations, ALEPH, DELPHI, L3 and OPAL, have searched for the neutral Higgs bosons which are predicted by the Minimal Supersymmetric standard model (MSSM). The data of the four collaborations are statistically combined and examined for their consistency with the background hypothesis and with a possible Higgs boson signal. The combined LEP data show no significant excess of events which would indicate the production of Higgs bosons. The search results are used to set upper bounds on the cross-sections of various Higgs-like event topologies. The results are interpreted within the MSSM in a number of “benchmark” models, including CP-conserving and CP-violating scenarios. These interpretations lead in all cases to large exclusions in the MSSM parameter space. Absolute limits are set on the parameter cosβ and, in some scenarios, on the masses of neutral Higgs bosons.
494 citations
TL;DR: A new cobalt-catalyzed coupling of aryl halides with thiophenols and alkanethiols is reported, which represents an interesting addition to previously known methods to synthesize thioethers.
405 citations
TL;DR: In this paper, the authors examined the theoretical predictions of critical thrust force at the onset of delamination, and compared the effects of different drill bits, including saw drill, candle stick drill, core drill and step drill.
Abstract: Drilling is the most frequently employed operation of secondary machining for fiber-reinforced materials owing to the need for joining structures Delamination is among the serious concerns during drilling Practical experience proves the advantage of using such special drills as saw drill, candle stick drill, core drill and step drill The experimental investigation described in this paper examines the theoretical predictions of critical thrust force at the onset of delamination, and compares the effects of these different drill bits The results confirm the analytical findings and are consistent with the industrial experience Ultrasonic scanning is used to evaluate the extent of drilling-induced delamination The advantage of these special drills is illustrated mathematically as well as experimentally, that their thrust force is distributed toward the drill periphery instead of being concentrated at the center The allowable feed rate without causing delamination is also increased The analysis can be extended to examine the effects of other future innovative drill bits
373 citations
TL;DR: A simple approach of ultrasound assisted coating of paper with ZnO nanoparticles (∼20 nm) without the aid of binder is reported for the first time in this work as mentioned in this paper.
367 citations
TL;DR: In this article, the influence of La doping on the crystal structure and multiferroic properties of BiFeO3 (BFO) thin films was investigated, and the in-plane magnetization-field curves revealed that the room-temperature saturated magnetization of the BFO films increased with La doping.
Abstract: The influence of La doping on the crystal structure and multiferroic properties of BiFeO3 (BFO) thin films was investigated. BFO-based films of pure perovskite phase were deposited on BaPbO3∕Pt∕TiOx∕SiO2∕Si substrates by rf-magnetron sputtering. The increased dielectric constant and remanent polarization of the La-doped BFO films were due to the increased lattice parameters and an improved crystallinity. The polarization switching and the fatigue behavior of the BFO films were significantly enhanced by the La doping. The in-plane magnetization-field curves revealed that the room-temperature saturated magnetization of the BFO films increased with La doping.
309 citations
TL;DR: This work has developed a method for attaching molecules to the surface of PPy through biotin–streptavidin coupling, which provides a novel platform for controlled drug delivery from a conductive polymer substrate.
Abstract: An externally controlled, polymeric drug-delivery system potentially allows for release profiles that can be tailored to match physiologic processes. [1] Current implantable electronic delivery systems are not biodegradable and often require additional components, while extended- or controllable-release polymeric systems that have been used do not allow for switchable release profiles. [2,3] Conducting polymers (e.g., polypyrrole (PPy)) offer the possibility of controllable drug administration through electrical stimulation. [4] However, the use of conductive polymers in delivery systems has been restricted due to limitations in the choice of dopant and the molecular weight of the delivered drug. To circumvent these barriers, we have developed a method for attaching molecules to the surface of PPy through biotin–streptavidin coupling. After attachment of the desired molecule to the biotin dopant, drug release is triggered through electrical stimulation. This method provides a novel platform for controlled drug delivery from a conductive polymer substrate. Because of PPy’s beneficial chemical properties and ease of preparation, it is often chosen for biological applications. [5–7] PPy’s favorable biocompatibility also makes it an ideal electroactive polymer for drug-delivery applications. [8–13] Addi
TL;DR: In vitro reconstruction of the heterogeneous lobule-mimetic radial pattern with good cell viability after cell patterning is demonstrated and reported by this cell-lab chip.
Abstract: Biomimetic heterogeneous patterning of hepatic and endothelial cells, which start from randomly distributed cells inside the microfluidic chamber, via the chip design of enhanced field-induced dielectrophoresis (DEP) trap is demonstrated and reported in this paper. The concentric-stellate-tip electrode array design in this chip generates radial-pattern electric fields for the DEP manipulation of the live liver cells. By constructing the geometric shape and the distribution of stellate tips, the DEP electrodes enhance the desired spatial electric-field gradients to guide and snare individual cells to form the desired biomimetic pattern. With this proposed microfluidic chip design, the original randomly distributed hepatocytes inside the microfluidic chamber can be manipulated in parallel and align into the desired pearl-chain array pattern. This radial pattern mimics the lobular morphology of real liver tissue. The endothelial cells, then, are snared into the additional pearl-chain array and settle at the space in-between the previous hepatic pearl-chain array. By this cell-lab chip, we demonstrate the in vitro reconstruction of the heterogeneous lobule-mimetic radial pattern with good cell viability after cell patterning. This work reports the rapid in-parallel patterning of the dual types of live liver cells via the enhanced DEP trap inside the microfluidic chip.
TL;DR: A comparative study of FE measurements between SnO2 nanorods with uniform diameters and these beaklike nanorod suggests that the shape and curved tips are important factors in determining the FE properties.
Abstract: Beaklike SnO2 nanorods were synthesized by a vapor-liquid-solid approach using Au as a catalyst. The nanorods grow along the [10 1] direction and the beak is formed by switching the growth direction to [1 12] through controlling the growth conditions at the end of the synthesis. The photoluminescence (PL) spectrum of the nanorods exhibits visible light emission with a peak at 602 nm. The field-emission (FE) properties of the nanorods have been measured to exhibit a turn-on field of 5.8 V microm(-1). A comparative study of FE measurements between SnO2 nanorods with uniform diameters and these beaklike nanorods suggests that the shape and curved tips are important factors in determining the FE properties.
TL;DR: In this article, the authors used the constraints imposed by heteroepitaxy as well as film growth mechanisms, shown in Figure 1a, to create long-range order in the domain structure of BFO.
Abstract: With an ever-expanding demand for data storage, transducers, and microelectromechanical (MEMS) systems applications, materials with superior ferroelectric and piezoelectric responses are of great interest. The lead zirconate titanate (PZT) family of materials has served as the cornerstone for such applications up until now. A critical drawback of this material, however, is the presence of lead and the recent concerns about the toxicity of lead-containing devices. Recently, the lead-free ferroelectric BiFeO3 (BFO) has attracted a great deal of attention because of its superior thin-film ferroelectric properties, which are comparable to those of the tetragonal, Ti-rich PZT system; therefore, BFO provides an alternate choice as a “green” ferro/piezoelectric material. Another advantage of BFO is its high ferroelectric Curie temperature (Tc = 850 °C in single crystals), [3,4] which enables it to be used reliably at high temperatures. The ferroelectric domain structure of epitaxial BFO films are typically discussed in the context of the crystallographic model of Kubel and Schmid; however, by suppressing other structural variants in BFO, we can obtain periodic domain structures that may open additional application opportunities for this material. Ferroelectrics with periodic domain structures are of great interest for applications in photonic devices and nanolithography. Such a periodic polarization could be obtained by applying an external electric field while utilizing lithographically defined electrodes or by a direct writing process. To obtain sub-micrometer feature sizes, however, domain engineering using a scanning force microscope with an appropriate bias voltage must be used to fabricate the patterned domain structures. Unfortunately, this method works only on small areas and is limited by its slow scanning rate. Theoretical models predict the feasibility of controlling the domain architecture in thin films through suitable control over the heteroepitaxial constraints. In the case of BFO thin films, we have found that such a control is indeed possible, mainly through control over the growth of the underlying SrRuO3 electrode. Using this approach, we demonstrate the growth of highly ordered 1D ferroelectric domains in 120 nm thick BFO films. On the (001)C perovskite surface there are eight possible ferroelectric polarization directions corresponding to four structural variants of the rhombohedral ferroelectric thin film. (For simplicity, the c and o subscripts refer to the pseudocubic structures for BFO and orthorhombic structures of SrRuO3 (SRO) and DyScO3(110)O (DSO), respectively.) Domain patterns can develop with either {100}C or {101}C boundaries for (001)C-oriented rhombohedral films. [12] In both cases, the individual domains in the patterns are energetically degenerate and thus equal-width stripe patterns are theoretically predicted. When the spontaneous polarization is included in the analysis, the {100}C boundary patterns have no normal component of the net polarization, whereas the {101}C boundary patterns correspond to the fully poled state. The formation of domain patterns leads to the release of elastic energy at the expense of increased interfacial energy associated with the domain boundaries. Therefore, four possible polarization variants still exist when one examines large areas of the sample. If control over the ferroelectric domain structure is desired, one has to recourse to other approaches. In our work, we have used the constraints imposed by heteroepitaxy as well as filmgrowth mechanisms, shown in Figure 1a, to create long-range order in the domain structure of BFO. First, we use the fact that on the (110)O surface the DSO lattice is extremely closely matched to that of SRO. Further, the small structural anisotropy in DSO is used to pin the structure of the SRO layer C O M M U N IC A IO N S
TL;DR: This paper presents a constrained weighted least squares (CWLS) mobile positioning approach that encompasses all the above described measurement cases and shows that all the developed CWLS location estimators achieve zero bias and the Cramér-Rao lower bound approximately when measurement error variances are small.
Abstract: The problem of locating a mobile terminal has received significant attention in the field of wireless communications. Time-of-arrival (TOA), received signal strength (RSS), time-difference-of-arrival (TDOA), and angle-of-arrival (AOA) are commonly used measurements for estimating the position of the mobile station. In this paper, we present a constrained weighted least squares (CWLS) mobile positioning approach that encompasses all the above described measurement cases. The advantages of CWLS include performance optimality and capability of extension to hybrid measurement cases (e.g., mobile positioning using TDOA and AOA measurements jointly). Assuming zero-mean uncorrelated measurement errors, we show by mean and variance analysis that all the developed CWLS location estimators achieve zero bias and the Cramer-Rao lower bound approximately when measurement error variances are small. The asymptotic optimum performance is also confirmed by simulation results.
TL;DR: In this article, the effect of vanadium addition on the microstructure and properties of Al0.5CoCrCuFeNi high-entropy alloy was investigated by scanning electron microscopy, energy dispersive spectrometry, and X-ray diffraction.
Abstract: The authors studied the effect of vanadium addition on the microstructure and properties of Al0.5CoCrCuFeNi high-entropy alloy. The microstructure of Al0.5CoCrCuFeNiV
x
(x=0 to 2.0 in molar ratio) alloys was investigated by scanning electron microscopy, energy dispersive spectrometry, and X-ray diffraction. With little vanadium addition, the alloys are composed of a simple fcc solid-solution structure. As the vanadium content reaches 0.4, a BCC structure appears with spinodal decomposition and envelops the FCC dendrites. From x=0.4 to 1.0, the volume fraction of bcc structure phase increases with the vanadium content increase. When x=1.0, fcc dendrites become completely replaced by bcc dendrites. Needle-like σ-phase forms in bcc spinodal structure and increases from x=0.6 to 1.0 but disappears from x=1.2 to 2.0. The hardness and wear resistance of the alloys were measured and explained with the evolution of the microstructure. The hardness values of the alloys increase when the vanadium content increases from 0.4 to 1.0 and peak (640 HV) at a vanadium content of 1.0. The wear resistance increases by around 20 pct as the content of vanadium increases from x=0.6 to 1.2 and levels off beyond x=1.2. The optimal vanadium addition is between x=1.0 and 1.2. Compared with the previous investigation of Al0.5CoCrCuFeNi alloy, the vanadium addition to the alloy promotes the alloy properties.
TL;DR: In this article, the main effects of R&D intensity, knowledge stocks, and commercialization orientation on firm performance were examined, as well as the interaction effects among the above variables.
TL;DR: It is shown that β1-integrin and E-cadherin activity with specific blocking antibodies, ion chelators, and RGD-sequence-containing peptides mediate the formation of spheroids through the establishment of complex cell-cell and cell-extracellular matrix (ECM) interactions.
Abstract: A spheroid is an in vitro multicellular aggregate that provides a microenvironment resembling that of normal tissue in vivo. Although cell adhesion molecules such as integrins and cadherins have been implicated in participating in the process of spheroid formation, little is known about the timing of their action. In this study, we have employed an image-based quantitative method to investigate the compactness of cell aggregates during hepatoma spheroid formation in a dynamic fashion. By modulating β1-integrin and E-cadherin activity with specific blocking antibodies, ion chelators, and RGD-sequence-containing peptides, we show that these cell adhesion molecules mediate the formation of spheroids through the establishment of complex cell-cell and cell-extracellular matrix (ECM) interactions. The dynamics of spheroid formation can be separated into three stages. In the first stage, ECM fibers act as a long-chain linker for the attachment of dispersed single-cells to form loose aggregations through the binding of integrins. This is followed by a delay period in which cell aggregates pause in compaction, presumably because of the accumulation of sufficient amounts of E-cadherins. In the third stage, strong homophilic interaction of E-cadherins is a major factor for the morphological transition from loose cell aggregates to compact spheroids. These findings thus provide comprehensive information on the molecular mechanisms and dynamics of hepatoma spheroid formation.
TL;DR: In this paper, multi-element nitride films of AlCrTaTiZr high-entropy alloy have been prepared by reactive radio-frequency magnetron sputtering and the influences of nitrogen flow ratio on the chemical composition, microstructure and mechanical properties of the deposited nitride film have been investigated.
Abstract: Multi-element nitride films of AlCrTaTiZr high-entropy alloy have been prepared in this study by reactive radio-frequency magnetron sputtering The influences of nitrogen flow ratio on the chemical composition, microstructure and mechanical properties of the deposited nitride films have been investigated The AlCrTaTiZr alloy film exhibited an amorphous structure, while a simple face-center-cubic solid-solution structure was observed in the nitride films prepared under different nitrogen flow ratios The multi-element AlCrTaTiZr nitride films exhibited much improved mechanical properties as compared with conventional nitride hard coatings of transition metals
TL;DR: In this article, a modified Halpin-Tsai equation was proposed to evaluate the Young's modulus and tensile strength of the MWNTs/phenolic composites by adopting an orientation factor and an exponential shape factor in the equation.
TL;DR: A stochastic diffusion process is used to model a typical SSADT problem, and under the constraint that the total experimental cost does not exceed a predetermined budget, the optimal settings of variables are obtained by minimizing the asymptotic variance of the estimated 100p/sup th/ percentile of the product's lifetime distribution.
Abstract: Today, many products are designed to function for a long period of time before they fail. For such highly-reliable products, collecting accelerated degradation test (ADT) data can provide useful reliability information. However, it usually requires a moderate sample size to implement an ADT. Hence, ADT is not applicable for assessing the lifetime distribution of a newly developed or very expensive product which only has a few available test units on hand. Recently, a step-stress ADT (SSADT) has been suggested in the literature to overcome the above difficulty. However, in designing an efficient SSADT experiment, the issue about how to choose the optimal settings of variables was not discussed, such as sample size, measurement frequency, and termination time. In this study, we first use a stochastic diffusion process to model a typical SSADT problem. Next, under the constraint that the total experimental cost does not exceed a predetermined budget, the optimal settings of these variables are obtained by minimizing the asymptotic variance of the estimated 100p/sup th/ percentile of the product's lifetime distribution. Finally, an example is used to illustrate the proposed method.
TL;DR: In this article, the growth of aligned and uniform α-Fe2O3 nanowire (NW) arrays has been achieved by a vapor-solid process, and the experimental conditions, such as type of substrate, local growth and geometrical environment, gas-flow rate, and growth temperature have been systematically investigated.
Abstract: Growth of aligned and uniform α-Fe2O3 nanowire (NW) arrays has been achieved by a vapor–solid process. The experimental conditions, such as type of substrate, local growth and geometrical environment, gas-flow rate, and growth temperature, under which the high density α-Fe2O3 NW arrays can be grown by a vapor–solid route via the tip-growth mechanism have been systematically investigated. The density of the α-Fe2O3 NWs can be enhanced by increasing the concentration of Ni atoms inside the alloy substrate. The synthesized temperature can be as low as 400 °C. Fe3O4 NWs can be produced by converting α-Fe2O3 NWs in a reducing atmosphere at 450 °C. The transformation of phase and structure have been observed by in situ transmission electron microscopy. The magnetic and field-emission properties of the NWs indicate their potential applications in nanodevices.
TL;DR: It is suggested that a temporal gradient of Chinmo (Chinmo(high) --> Chinmo(low)) helps specify distinct birth order-dependent cell fates in an extended neuronal lineage.
TL;DR: A Bayesian RFS filter is developed that simultaneously tracks the time-varying speaker locations and number of speakers by applying a sequential Monte Carlo implementation.
Abstract: Speaker location estimation techniques based on time-difference-of-arrival measurements have attracted much attention recently. Many existing localization ideas assume that only one speaker is active at a time. In this paper, we focus on a more realistic assumption that the number of active speakers is unknown and time-varying. Such an assumption results in a more complex localization problem, and we employ the random finite set (RFS) theory to deal with that problem. The RFS concepts provide us with an effective, solid foundation where the multispeaker locations and the number of speakers are integrated to form a single set-valued variable. By applying a sequential Monte Carlo implementation, we develop a Bayesian RFS filter that simultaneously tracks the time-varying speaker locations and number of speakers. The tracking capability of the proposed filter is demonstrated in simulated reverberant environments
TL;DR: Osmium(II) complexes possessing β-diketonate, quinolinate, diimine and C-linked pyridyl azolate chelates reveal interesting structural and photophysical properties as discussed by the authors.
Abstract: Osmium(II) complexes possessing β-diketonate, quinolinate, diimine, and C-linked pyridyl azolate chelates reveal interesting structural and photophysical properties. Spectroscopic and dynamic measurements, in combination with theoretical analyses, have provided an important understanding of the electronically excited state properties of these complexes, such as the energy gap and nature of the lower lying states, rate for intersystem crossing, and the efficiency of corresponding radiative decay and nonradiative deactivation processes. This review also reports on the synthetic processes
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18 Dec 2006TL;DR: A phase change memory cell includes first and second electrodes electrically coupled by a phase change element as discussed by the authors, which can transition from crystalline to amorphous states at a lower temperature than the higher reset transition temperature.
Abstract: A phase change memory cell includes first and second electrodes electrically coupled by a phase change element. At least a section of the phase change element comprises a higher reset transition temperature portion and a lower reset transition temperature portion. The lower reset transition temperature portion comprises a phase change region which can be transitioned, by the passage of electrical current therethrough, from generally crystalline to generally amorphous states at a lower temperature than the higher reset transition temperature portion. The phase change element may comprise an outer, generally tubular, higher reset transition temperature portion surrounding an inner, lower reset transition temperature portion.
TL;DR: A sensitive method for the detection of cholera toxin (CT) using an electrochemical immunosensor with liposomic magnification followed by adsorptive square-wave stripping voltammetry is described.
Abstract: A sensitive method for the detection of cholera toxin (CT) using an electrochemical immunosensor with liposomic magnification followed by adsorptive square-wave stripping voltammetry is described Potassium ferrocyanide-encapsulated and ganglioside (GM1)-functionalized liposomes act as highly specific recognition labels for the amplified detection of cholera toxin The sensing interface consists of monoclonal antibody against the B subunit of CT that is linked to poly(3,4-ethylenedioxythiophene) coated on Nafion-supported multiwalled carbon nanotube caste film on a glassy carbon electrode The CT is detected by a “sandwich-type” assay on the electronic transducers, where the toxin is first bound to the anti-CT antibody and then to the GM1-functionalized liposome The potassium ferrocyanide molecules are released from the bounded liposomes on the electrode by lyses with methanolic solution of Triton X-100 The released electroactive marker is measured by adsorptive square-wave stripping voltammetry The sa
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31 Jul 2006TL;DR: In this article, manufacturing methods and integrated circuits for lowered contact resistance are disclosed that have contacts of reduced size, and they have been shown to reduce the resistance of programmable resistive RAM cells.
Abstract: Programmable resistive RAM cells have a resistance that depends on the size of the contacts. Manufacturing methods and integrated circuits for lowered contact resistance are disclosed that have contacts of reduced size.
TL;DR: The basic principles of bioreactor design are reviewed, the bioreactors commonly used for the tissue engineering of cartilage, bone and cardiovascular systems are assessed in terms of their performance and usefulness as mentioned in this paper.
Abstract: Bioreactors are essential in tissue engineering, not only because they provide an in vitro environment mimicking in vivo conditions for the growth of tissue substitutes, but also because they enable systematic studies of the responses of living tissues to various mechanical and biochemical cues. The basic principles of bioreactor design are reviewed, the bioreactors commonly used for the tissue engineering of cartilage, bone and cardiovascular systems are assessed in terms of their performance and usefulness. Several novel bioreactor types are also reviewed.
TL;DR: The tuning of CdSe quantum dot (QDs) sizes, and consequently their corresponding two-photon absorption (TPA) cross section, has been systematically investigated and is found to be empirically related via a power-law proportionality of 3.5+/-0.7 to the diameters of C dSe and CdTe QDs.
Abstract: The tuning of CdSe quantum dot (QDs) sizes, and consequently their corresponding two-photon absorption (TPA) cross section, has been systematically investigated. As the size (diameter) of the quantum dots increases, the TPA cross section is found to be empirically related via a power-law proportionality of 3.5±0.5 and 5.6±0.7 to the diameters of CdSe and CdTe QDs, respectively. The results are tentatively rationalized via a theoretical model of two-photon excitation properties in a system incorporating excitons and defects.