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In this research, we propose a sensor system consisting of a power-generating sensor with a textile structure comprising piezoresistive, piezoelectric, and supercapacitor threads, and a circuit for efficient energy delivery. A multifunctional piezoelectric energy harvester for energy generation, piezoresistive strain, and capacitive tactile sensors to detect motion, and supercapacitor for energy storage were implemented through the proposed sensor platform. An energy management circuit was also added to the platform to store the generated energy and supply it for sensor operation. The devices were fabricated into a textile structure using functional threads in a total area of 130 mm × 130 mm with a 7 × 7 thread array. The piezoresistive strain sensor exhibited a resistance change of approximately 24% at a maximum strain of 24%, and the capacitive tactile sensor exhibited a change rate of 12.5% at a maximum vertical force of 5 N. In addition, the energy source, a piezoelectric energy harvester, obtained a power of 440 μW at a 6 Hz motion and a 3 MΩ load resistor. In the energy management circuits, using a parallel synchronized switch harvesting on inductor (P-SSHI) circuit and a voltage doubler, increased the voltage stored in the supercapacitor by 119%.

In this work, we report a planar Si-based ferroelectric field-effect transistor (FEFET) characterized by a high memory window (MW) of 4.79 V, ten-year retention, and pass disturb-free characteristics. This achievement is realized through the use of a 20-nm-thick laminated Hf $_{{0}.{5}}$ Zr0.5O2 (L-HZO) film with Al2O3 (AO)-insertion layers (ILs). The 2.4-Å-thick AO-ILs effectively severed the bulk-HZO film and scaled down each FE-thickness ( ${t}_{\text {FE}}$ ) in the L-HZO. This resulted in suppression of non-FE monoclinic phase formation to less than 10%, and more notably, an increase in the coercive field ( ${E}_{C}$ ) within the FE stack. With an increase in the number of HZO-lamination ( ${N}_{\text {HZO}}$ ), the ${E}_{C}$ was enhanced by 76% in L-HZO ( ${N}_{\text {HZO}}$ = 4) compared to single-HZO (S-HZO). This led to an increase in effective polarization ( ${P}_{\text {eff}}$ ), representing the portion of remnant polarization ( ${P}_{\text {r}}$ ) uncompensated by channel-injected charge, thereby validly influencing the threshold voltage ( ${V}_{\text {T}}$ ) shift of FEFET. The augmented ${P}_{\text {eff}}$ in L-HZO (350% increase compared to S-HZO) was directly confirmed through a more pronounced ${V}_{\text {T}}$ shift by the change of ${P}_{\text {r}}$ , which was 230% steeper in L-HZO compared to S-HZO. The revealed mechanism behind the enhanced MW and reliability in laminated-FE, stemming from the increased ${P}_{\text {eff}}$ rooted in enlarged ${E}_{C}$ , paves the way for designing the FE-stack for high-density memory or neuromorphic applications.

This study presents a material selection strategy for the interfacial layer (IL) in ferroelectric (FE) memory stacks. The nucleation-limited switching (NLS) model was applied to analyze the switching kinetics of the metal/FE/insulator/metal (MFIM) structure, where Hf0.5Zr0.5O2 (HZO) was used as the FE. Activation field ( ${E}_{a}$ ) and characteristic switching time ( $\tau $ ) were extracted for various 1-nm-thick ILs, including those of SiO2, La2O3 (LaO), AlN, and Hf3N4 (HfN). The adaptation of HZO/LaO reduced the ${E}_{a}$ by ~44% in relation to that of HZO without an IL (MFM-HZO), resulting in considerably faster switching in the low-electric-field ( ${E}$ ) region (< 4 MV $\cdot $ cm $^{-{1}}$ )—a highly suitable criterion for applications in 1-bit nonvolatile memories. In contrast, HZO/AlN showed the broadest $\tau $ distribution due to the large ${E}_{a}$ ( $\sim $ 200% of MFM-HZO), which led to the stabilization of multiple-intermediate polarization states. Promising potentiation and depression characteristics were obtained for multibit synapse applications when an incremental pulse time scheme with a step size of 10 ns was used.

The rise in availability of neuroimaging has led to an increase in incidentally discovered meningiomas. These tumors are typically asymptomatic and tend to display slow growth. Treatment options include observation with serial monitoring, radiation, and surgery. Although optimal management is unclear, clinicians recommend a conservative approach, which preserves quality of life and limits unnecessary intervention. Several risk factors have been investigated for their potential utility in the development of prognostic models for risk assessment. Herein, the authors review the current literature on incidental meningiomas, focusing their discussion on potential predictive factors for tumor growth and appropriate management practices.

We study theoretically the mode conversion and the resonant absorption of high-frequency electromagnetic waves into longitudinal modes in magnetized and stratified plasmas in the case where the external magnetic field is perpendicular to both the directions of inhomogeneity and wave propagation. Mode conversion is shown to occur only when the waves are extraordinary waves. We develop an efficient method for calculating the mode conversion coefficient for arbitrary spatial configurations of the plasma density and the external magnetic field in a numerically exact manner using the invariant imbedding method. We calculate the mode conversion coefficient extensively as a function of the incident angle, the external magnetic field, and the plasma density in the incident region. We show that there is strong asymmetry under the sign change of the incident angle and the external magnetic field and find that the mode conversion coefficient is close to one in certain ranges of the parameter values. We discuss the implications of our results in plasma heating phenomena.

Introduction The service sector of the world economy has grown substantially since World War II. In 1989, the service sector accounted for approximately 60 percent of the world's gross domestic [...]

The Li2MnO3cathode material is vulnerable to complex degradation behaviors during the operation of battery although it has attracted much attention recently due to its potentially large capacity. In this study, we comprehensively examined the degradation process in Li2MnO3, using theoretical density functional computations as well as experimental techniques (in situX-ray absorption near edge structure spectroscopy, X-ray diffraction, and Raman spectroscopy). Our study reveals that during the delithiation process, the Li ions mixed in the Mn layer are removed together with those in the Li layer, thereby inducing the release of oxygen atoms. The oxygen loss reaction is energetically favorable at the highly delithiated states, and it can reduce the plateau voltage in the charging curve. Such oxygen loss was observed during or even before the second cycle and furthermore it accelerates the phase transformation of the layered structure to a spinel one. Our results also suggest that oxygen release can be prevented when H ions are exchanged with Li ions during the charging process.

This paper presents a power-generating sensor array in a flexible and stretchable form. The proposed device is composed of a woven structure that provides various features, including a capacitive tactile sensor, piezoresistive strain sensor, triboelectric energy harvester, and piezoelectric energy harvester. The device is implemented in a textile structure using functional threads implemented with lead zirconate, carbon nanotube, polydimethylsiloxane, and silver nanowire (Ag NW). A stretching force can be detected by measuring the resistance change in the Ag NW composite layer on each thread. Further, the magnitude and location of the vertical force can be detected by measuring the capacitance variation on each capacitive cell that is formed by the gap between two Ag NW layers at the crossing points of each weft and warp thread. For the energy harvesters, the maximum power was measured as 108 μW at 3 MΩ from the triboelectric energy harvesting when the device was pushed in the vertical direction. When a stretching force was applied, a maximum of 60.3 μW at 1 MΩ was measured from the piezoelectric energy harvester.

As potential successors to intercalation-based battery systems, Li-air batteries have attracted enormous research attention because of their higher theoretical specific energy compared with conventional batteries, in terms of unit of energy per active material mass. However, this unit complicates the estimation of realistically attainable cell-scale energy densities because all other indispensable cell components are excluded. Here, we report Li-O2batteries with an ultra-thin, customized gas-diffusion layer, highly conductive, stable polymeric ionic-liquid separator, and folded cell structure that reduce the volume and mass of multiple cell components. A complete cell-scale specific energy and energy density of 1,214 Wh kgcell−1and 896 Wh Lcell−1, respectively, were experimentally achieved. Cell-scale electrochemical phenomena were simulated using a multiphysics model that included the oxygen flow caused by the cathode reaction, dynamic porosity changes, and resistance increase during Li2O2formation. Both the cell geometry and cathode composition dramatically affected the cell's capacity.

Nano-structured silicon anodes are attractive alternatives to graphite in lithium-ion batteries; however, despite recent progress in nano-engineered composites, its use remains limited. One of the issues, particularly in silicon-dominated anodes, is the poor Coulombic efficiency of lithium–silicon processes. Previous studies have shown that repeating the amorphous–crystalline hysteretic lithium–silicon phase transformations can abruptly improve irreversibility and eventually minimize cumulative irreversible lithium consumption in exchange of certain parasitic capacity sacrifice. Here, we reveal mechanism behind the phenomenon that the single phase transformation spontaneously and pseudo-topologically transforms nano-structured silicon into quantum-scale frameworks without gravimetric loss. The way it forms is clearly distinct from ever explored formation mechanism of porous nano-structures such as (electro)chemical etching, Kirkendall voiding, and percolation theory. Further, we implanted the structural transformation feature into lithium-ion full cells, largely redesigning the conventional one, by modulating cathode/anode capacity loading balance and prelithiation dose in the anode to embed the unique feature in the cells. We show that the cell preferentially triggers the efficient irreversibility-depletion phenomenon upon cycling and consequently outperforms conventional silicon-based cells.

In the past, resource sharing has been extensively studied for OLAP workloads. Naturally, the question arises, why studies mainly focus on OLAP and not on OLTP workloads? At first sight, OLTP queries - due to their short runtime - may not have enough potential for the additional overhead. In addition, OLTP workloads do not only execute read operations but also updates. In this paper, we address query sharing for OLTP workloads. We first analyze the sharing potential in real-world OLTP workloads. Based on those findings, we then present an execution strategy, called OLTPShare that implements a novel batching scheme for OLTP workloads. We analyze the sharing benefits by integrating OLTPShare into a prototype version of the commercial database system SAP HANA. Our results show for different OLTP workloads that OLTPShare enables SAP HANA to provide a significant throughput increase in high-load scenarios compared to the conventional execution strategy without sharing.

For developing the industrially feasible Ni-rich layered oxide cathode with extended cycle life, it is necessary to mitigate both the mechanical degradation due to intergranular cracking between primary particles and gas generation from the reaction between the electrolyte and residual Li in the cathode. To simultaneously resolve these two issues, we herein propose a simple but novel method to reinforce the primary particles in LiNi0.91Co0.06Mn0.03O2by providing a Li-reactive material, whose spinel interphase is coherent with the surface of the cathode. The modified structure significantly outperforms analogous bare samples: they conserve more than 90% of the initial capacity after 50 cycles and also exhibit a greater rate capability. By tracking the same particle location during cycling, we confirmed that the current method significantly reduces crack generation because the provided coating material can penetrate inside the grain boundary of the secondary particle and help maintain the volume of the primary particle. Finally, first-principles calculations were implemented to determine the role of this spinel material, i.e., having intrinsically isotropic lattice parameters, superior mechanical properties, and only a small volume change during delithiation. We believe that the proposed method is straightforward and cost-effective; hence, it is directly applicable for the mass production of Ni-rich cathode material to enable its commercialization.

Most existing activity-based travel demand models are typically implemented on a tour-based microsimulation framework. Two approaches are available to describe people’s daily decision-making processes on activity and travel in the activity-based model framework: rubber banding and growing scheduling. The growing-scheduling approach requires a series of linked dynamic discrete choices of activity episodes, locations, and travel modes to build incrementally an entire day’s activity-travel patterns for individuals in households. To incorporate explicitly time dependencies into activity episode choice and duration, a hazard-based duration model in a discrete-time framework is introduced; this framework is essentially the same as a discrete choice model with temporal dummies as the simplest form of dynamic discrete choice models. In the application of the discrete–time duration model to activity duration analysis, complex situations of activity-travel data are considered; these include multiple states of origin activity, competing risks of destination activity, and a multilevel structure for recurrent activity episodes within individuals. In addition, a circular, or periodic, variable is introduced as a combination of sine and cosine to model time-of-day effects.

Most existing activity-based travel demand models are typically implemented on a tour-based microsimulation framework. Two approaches are available to describe people’s daily decision-making processes on activity and travel in the activity-based model framework: rubber banding and growing scheduling. The growing-scheduling approach requires a series of linked dynamic discrete choices of activity episodes, locations, and travel modes to build incrementally an entire day’s activity-travel patterns for individuals in households. To incorporate explicitly time dependencies into activity episode choice and duration, a hazard-based duration model in a discrete-time framework is introduced; this framework is essentially the same as a discrete choice model with temporal dummies as the simplest form of dynamic discrete choice models. In the application of the discrete–time duration model to activity duration analysis, complex situations of activity-travel data are considered; these include multiple states of origin activity, competing risks of destination activity, and a multilevel structure for recurrent activity episodes within individuals. In addition, a circular, or periodic, variable is introduced as a combination of sine and cosine to model time-of-day effects.

We consider the spreading of an initially localized wave packet in one-dimensional hybrid ordered-quasiperiodic lattices. We consider two diffrent kinds of quasiperiodic sequences, which are the Cantor and the period-doubling sequences. From numerical calculations based on the discrete Schrödinger equation, we demonstrate that hybrid ordered-quasiperiodic lattices can support the super-ballistic spreading of a wave packet with very large spreading exponents for certain transient time windows. Remarkably, in the case of the sublattice with the on-site potential obeying the period-doubling quasiperiodic sequence, we find that the super-ballistic exponent can be larger than six. We also point out that previous explanations of this phenomenon based on a generalized version of the point source model are incorrect.

The Goos-Hänchen shift of pwave beams incident on a metal-nonlinear dielectric bilayer in the Kretschmann configuration is studied theoretically. The reflectance, the phase of the reflection coefficient and the Goos-Hänchen shift are calculated in a numerically precise manner by using the invariant imbedding method. The Goos-Hänchen shift has been found to be able to take both extremely large positive and negative values due to surface plasmon excitations and very strong bistability and unique hysteresis phenomena appear. In addition, several previous results on the intensity dependence of the Goos-Hänchen shift are pointed out to be erroneous.

Sequence alignment, also known as optimal matching, has recently received new attention for use in analysis of activity patterns. The method is almost always combined with a data reduction technique, such as clustering analysis. The cluster-based approach is powerful for discovery of a typology of activity patterns of people. However, the use of the combination of the sequence alignment and cluster analysis methodologies does not seem to be successful for the identification of diverse factors that would affect activity sequence patterns. This outcome is because the loss of too much information may occur when the set of activity sequences is reduced to a small number of clusters. This paper proposes the use of a new combination of the sequence alignment and discrepancy analysis methodologies instead of the cluster-based approach. As a generalization of the principle of analysis of variance, discrepancy analysis allows the association between activity sequences characterized by a pairwise distance matrix and one or more covariates to be evaluated. In addition, an induction tree complements the sequence discrepancy analysis and displays how individual activity sequences vary with the value of covariates.

The propagation of optical vortex beams through disordered nonlinear photonic lattices is numerically studied. The vortex beams are generated by using a superposition of several Gaussian laser beams arranged in a radially-symmetric manner. The paraxial nonlinear Schrödinger equation describing the longitudinal propagation of the beam array through nonlinear triangular photonic lattices with two-dimensional disorder is solved numerically by using the split-step Fourier method. We find that due to the spatial disorder, the vortex beam is destabilized after propagating a finite distance and new vortex-antivortex pairs are nucleated at the positions of perfect destructive interference. We also find that in the presence of a self-focusing nonlinearity, the vortex-antivortex pair nucleation is suppressed and the vortex beam becomes more stable, while a self-defocusing nonlinearity enhances the vortex-antivortex pair nucleation.

We study theoretically the influence of nonlinear gain effects on the transmission and the Anderson localization of waves in both uniform and random one-dimensional amplifying media by using the discrete nonlinear Schrödinger equation. In uniform amplifying media with nonlinear gain, we find that the strong oscillatory behavior of the transmittance and the reflectance for odd and even values of the sample length disappears for large nonlinearities. The exponential decay rate of the transmittance in the asymptotic limit is found to be independent of nonlinear gain. In random amplifying media, we find that the maximum values of the disorder-averaged logarithmic transmittance and reflectance depend nonmonotonically on the strength of nonlinear gain. We also find that the localization length is independent of nonlinear gain. In other words, the Anderson localization is neither enhanced nor weakened due to nonlinear gain. In both the uniform and the random cases, the crossover length, which is the critical length for the amplification to be efficient, is strongly reduced by the nonlinear nature of the gain.

We develop an invariant imbedding method for the computation of the electromagnetic scattering cross-section from three-dimensional spherical bodies. We demonstrate that we can precisely calculate quantities of interest in the scattering and the absorption of an incident plane wave in various situations, such as propagation through arbitrarily inhomogeneous media and multilayered structures. Examples include scattering by a Luneburg lens and by a spherical cavity enclosed in a spherical photonic crystal structure, the layers of which satisfy the Bragg conditions for the incident wavelengths. In the latter case, light confinement in a very small core with a radius of 1.55 µm with high quality factors at a level of 1.7 × 106could be achieved.

We study numerically the dynamics of an initially localized wave packet in one-dimensional nonlinear Schrödinger lattices with both local and nonlocal nonlinearities. Using the discrete nonlinear Schrödinger equation generalized by including a nonlocal nonlinear term, we calculate four different physical quantities as a function of time, which are the return probability to the initial excitation site, the participation number, the root-mean-square displacement from the excitation site and the spatial probability distribution. We investigate the influence of the nonlocal nonlinearity on the delocalization to self-trapping transition induced by the local nonlinearity. In the non-self-trapping region, we find that the nonlocal nonlinearity compresses the soliton width and slows down the spreading of the wave packet. In the vicinity of the delocalization to self-trapping transition point and inside the self-trapping region, we find that a new kind of self-trapping phenomenon, which we call partial self-trapping, takes place when the nonlocal nonlinearity is sufficiently strong.

Abstract: We study the behavior of the phase of the transmission coefficient t in random media by using the invariant imbedding method of wave propagation. We calculate the disorder average of t/t* for waves propagating in one-dimensional random media with uncorrelated Gaussian disorder in a numerically exact manner. We find that the analytical formula derived by Mello et al. [Phys. Rev. Lett. 67, 342 (1991)] is valid only after a major modification and only in the limit where the so-called random phase approximation is valid. We find that the disorder average of t/t* converges to a finite complex number in the large-size limit. We discuss the implications of our results for the probability distribution of the phase of the transmission coefficient.

Passive mode-locking of 1.3 m solid-state lasers is problematic for semiconductor saturable absorber mirrors (SESAMs) not only because of difficulties in their fabrication process but also in relation to the achievable parameters and damage resistivity. In contrast, single-walled carbon nanotube saturable absorbers (SWCNT-SAs) exhibit broadband absorption which is controllable by varying the nanotube diameter and chirality, and require relatively simple manufacturing processes. Here we report on steady-state mode-locked operation of a diode pumped Nd:YVO4laser on the 4F3/2→4I13/2transition at 1.342 m using a transmitting SWCNT-SA. The SWCNT-SA employed in the present work was fabricated by SWCNTs grown by high-pressure CO conversion technique, showing broad absorption around 1.3 m. The linear transmission at the laser wavelength was about 99%. The Nd:YVO4laser was longitudinally pumped by the unpolarized radiation of a 808 nm fiber-coupled laser diode. The ~1.2-m long cavity was optimized for large fundamental mode size. Above threshold the laser operated first in the CW mode, then had a range of Q-switched modelocked operation before reaching the regime of stable steady-state mode-locking. With an output coupler of 90% reflectivity, the average output power in the steady-state mode-locked regime reached 0.8 W at a slope efficiency of 14.5% with respect to the incident pump power. At a repetition rate of 127 MHz this corresponds to single pulse energy of 6.3 nJ. Such pulse energies are comparable to the best results obtained using SESAMs but the pulse duration of 16.5 ps measured in the present experiment is substantially shorter.

This study explores how an individual might view the utility of alternate courses of action throughout the day. Its novel proposition is that utility for daily activity-travel alternatives is updated rather than accumulated. As the day progresses, the utility attached to various activities is updated for reasons of need, satiation, and various idiosyncratic associations with time, such as business hours, darkness, and cultural norms. Dynamic choice models are developed for individual activity-travel patterns and it is shown how time-dependent utility may be represented. The model system is being developed for the Portland, Oregon, region as part of a new activity-based travel demand forecasting system. Dynamic components of the model include time-dependent choices of activity episodes and their duration, locations, and travel modes. Results are presented of the next-activity-choice model component, which subsumes both activity frequency and duration in its specification.

Nitrogen-doped Ge--Bi (8.4 at. %)--Te thin films, which show a rapidly decreasing sheet resistance and NaCl-type X-ray diffraction peaks above 225 \mbox{\circC}, were investigated by synchrotron-radiation-based high-resolution X-ray absorption spectroscopy (XAS) and photoelectron spectroscopy (XPS). As the as-deposited film transformed to the crystalline phase in an ultrahigh vacuum ambient, the N 1s and Bi 4f core levels chemically shifted towards higher binding energies (BEs), a lower-BE component developed at the Te 4d core level, and a higher-BE component developed at the Ge 3d core level. The nitrogen molecules, identified by the N K-edge absorption spectra, decreased in intensity and some of them were considered to have decomposed to form a N-content-increased quaternary system.

In asynchronous slow frequency hopping Bluetooth networks, packet collisions diminish the total link throughput. However, interference mitigation capability can reduce packet losses due to collisions. In this paper, an interference cancelling dual decision feedback (IC-DDF) Bluetooth receiver is proposed and its performance is evaluated for slow fading indoor channels. In addition to the bit error rate (BER) performance, the system level performance is evaluated by using the packet error rate (PER). To integrate the BER performance into the PER performance, a new geometric interpretation of packet error rate is introduced that uses an ensemble average of the received carrier to interference ratio (CIR). Also, a generalized packet collision probability is derived to analyze total link throughput.

With the proliferation of various geographic databases on the Internet, we have seen increasing needs for accessing them concurrently and remotely via the Web for high‐level decision making. In this paper, we present Middleware for Efficient Access to Databases through OpenGIS Wrappers (MEADOW), an object‐oriented middleware system we have developed to meet these needs. Current OpenGIS standard addresses many interoperability issues involved in such a global utilization of geographic databases. However, existing Simple Feature specification for CORBA (SFCORBA) implementations of OpenGIS proved to be insufficient for MEADOW. The main problems are the complexity of system development and maintenance, and the inefficiency of accessing remote data servers for processing region queries. We resolved the complexity problem by automatically generating a major portion of the application code, specifically wrappers on database servers and client library modules called transparent access providers. A MEADOW view definition language was developed as a high‐level specification language for this purpose. The efficiency problem was resolved by using a region‐based group prefetching of spatial objects from a geographic region. In addition, we implemented an OID‐based semijoin for efficient global query processing, and a region‐level locking to enhance the level of concurrency among region queries. Copyright © 2002 John Wiley & Sons, Ltd

Recent studies have shown that cache-conscious indexes such as the CSB+-tree outperform conventional main memory indexes such as the T-tree. The key idea of these cache-conscious indexes is to eliminate most of child pointers from a node to increase the fanout of the tree. When the node size is chosen in the order of the cache block size, this pointer elimination effectively reduces the tree height, and thus improves the cache behavior of the index. However, the pointer elimination cannot be directly applied to multidimensional index structures such as the R-tree, where the size of a key, typically, an MBR (minimum bounding rectangle), is much larger than that of a pointer. Simple elimination of four-byte pointers does not help much to pack more entries in a node.This paper proposes a cache-conscious version of the R-tree called the CR-tree. To pack more entries in a node, the CR-tree compresses MBR keys, which occupy almost 80% of index data in the two-dimensional case. It first represents the coordinates of an MBR key relatively to the lower left corner of its parent MBR to eliminate the leading O's from the relative coordinate representation. Then, it quantizes the relative coordinates with a fixed number of bits to further cut off the trailing less significant bits. Consequently, the CR-tree becomes significantly wider and smaller than the ordinary R-tree. Our experimental and analytical study shows that the two-dimensional CR-tree performs search up to 2.5 times faster than the ordinary R-tree while maintaining similar update performance and consuming about 60% less memory space.

The chemical and electrical properties of fluorinated silicon oxide films prepared by plasma enhanced chemical vapor deposition at 180°C were studied. The deposition of these films was made by incorporating CF4as the fluorine source into the deposition process of SiO2films using Si2H6and N2O. With increasing CF4flow, the deposition rate of these films decreased; meanwhile, the P-etch rate increased. With post-deposition anneal, the thickness of the films without CF4slightly decreased; meanwhile, the thickness slightly increased with the incorporation of CF4. The Fourier transform infrared (FTIR) spectroscopy showed that the characteristic peak around 940 cm−1due to the Si–F stretching bonds increased with increasing CF4flow, also the Si–O stretching wave number increased but its full width at half maximum decreased with increasing CF4flow. The dielectric constant evaluated by high frequency capacitance-voltage measurements decreased from 4.13 to 3.52 as the CF4flow increased. In addition, the effective oxide charge density and interface trap density also decreased with increasing CF4flow. The ramp current-voltage measurements showed that the leakage current density of the films decreased with increasing CF4flow. However, high average breakdown field strength with low early failures was observed for medium flow of CF4.

High-quality monolayer graphene as large as 1.2×1.2?cm^2 was synthesized by chemical vapor deposition and used as a transmitting saturable absorber for efficient passive mode-locking of a femtosecond bulk solid-state laser. The monolayer graphene mode-locked Cr:forsterite laser was tunable around 1.25?μm and delivered sub-100?fs pulses with output powers up to 230?mW. The nonlinear optical characteristics of the monolayer graphene saturable absorber and the mode-locked operation were then compared with the case of the bilayer graphene saturable absorber.