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Calcium vanadate nanorods with Ca10V6O25 phase have been synthesized by a hydrothermal process without any surfactants. Hydrothermal temperature, reaction time and calcium (Ca) raw materials play important roles in the formation and size of the calcium vanadate nanorods. The nucleation and crystal growth combined with crystal splitting process have been proposed to explain the formation and growth of calcium vanadate nanorods. The calcium vanadate nanorods are used as glassy carbon electrode-modified materials to analyze the electrochemical behaviors of tartaric acid. The calcium vanadate nanorod-modified glassy carbon electrode exhibits good performance for the electrochemical detection of tartaric acid with a detection limit of 2.4 μM and linear range of 0.005–2 mM. The analytical performance and straightforward fabrication method make the calcium vanadate nanorods promising for the development of electrochemical sensors for tartaric acid.

Nonuniform ferrite coupled line constructed by placing section of corrugated coupled lines on longitudinally magnetized ferrite substrates is investigated. Unlike the usual uniform ferrite coupled ...

A laboratory-scale submerged anaerobic membrane bioreactor (SAnMBR) was operated for over 160 days to assess the potential to treat kraft pulp mill evaporator condensate. Cake formation was identified as a dominant feature contributing to the deterioration of membrane performance. The influence of various operational parameters and sludge properties on sludge cake formation rate (CFR) was investigated. These included biogas sparging and permeate flow rates, as well as mixed liquor suspended solids (MLSS), soluble chemical oxygen demand (CODs) in the mixed liquor, and particle size distribution (PSD) and fractal dimension (Df) of particles. CFR was highly dependent on biogas sparging rate and permeate flow rate, and less dependent on MLSS. CODs, PSD and Df were found to significantly influence the CFR. Confocal laser scanning microscopic (CLSM) imaging and chemical analyses of extracellular polymeric substances (EPS) indicated that EPS was involved in sludge cake formation. Characterization of the sludge cake layers, when compared to the bulk sludge, indicated that smaller flocs and EPS preferentially accumulated in the sludge cake. The identification of factors including biogas sparging rate, permeate flow rate, CODs, EPS, PSD, and Df that impact the cake formation process provides a basis for selecting operating conditions to manage fouling in an SAnMBR.

Introduction In the face of population ageing, dementia is an urgent public health problem. Dementia has been reported to be a comorbidity of type 2 diabetes mellitus in older people, but the pathological mechanisms linking both conditions remains unclear. The major gene associated with pathology of dementia, especially Alzheimer's disease, is the apolipoprotein E (APOE) gene, which has also been implicated in predisposition to diabetes. Given the scarcity of epidemiological studies on possible interactions so far, we examined the association of type 2 diabetes alone and combined with APOE genotype with incidence of dementia in a cohort of older Germans followed for approximately 14 years while accounting for competing risk of death. Methods We used data from an on-going population-based prospective cohort study (ESTHER) in the state of Saarland in the south-west of Germany. In total, 9949 elderly participants aged 50–74 years were recruited from July 2000 to December 2002 by their general practitioners followed by 5 waves of interviews up to now. Data were collected using standardized self-administered questionnaires including health-related information and basic sociodemographics. Self-reported medical diagnoses of diabetes were validated by participants’ general practitioners at each interview. Dementia-related information was collected retrospectively among all ESTHER participants, including those who dropped out or deceased over the follow-up. APOE genotype was measured using TaqMan SNP genotyping assays and participants were divided into e4 allele carriers and non-carriers. Standard Cox proportional hazard regression models were used to analyze the association of diabetes, as well as diabetes combined with APOE e4 carrier status, with incidence of all-cause dementia and its main subtypes (vascular dementia and Alzheimer's disease). Fine and Gray competing risk models were used to analyze the association of diabetes and dementia after adjusting for competing risk of death. Results Of 5648 eligible participants with complete information, 793 had type 2 diabetes (mean age 63.8 ± 6.4 years) at baseline, and 4855 did not have type 2 diabetes (mean age 61.4 ± 6.5 years). Among the overall sample, 304 developed dementia, including 90 with Alzheimer's disease and 113 with vascular dementia. In the fully-adjusted Cox model, the risk of all-cause dementia was 61% higher (hazard ratio [HR]: 1.61; 95% confidence interval [CI]: 1.22–2.12) among type 2 diabetes patients than among non-diabetes patients. Adjusted HRs for Alzheimer's disease and vascular dementia were 2.30 (95% CI: 1.38–3.86) and 1.41 (95% CI: 0.89–2.25), respectively. After adjusting for competing risk of death, type 2 diabetes was associated with an adjusted HR of 1.47 (95% CI: 1.10–1.96) for all-cause dementia, 2.18 (95% CI: 1.27–3.75) for Alzheimer's disease and 1.27 (95% CI: 0.78–2.02) for vascular dementia. Compared with those who were neither type 2 diabetes patient nor APOE e4 carrier, those with both risk factors had significantly higher risk of Alzheimer's disease (HR: 4.10; 95% CI: 1.67–10.07), vascular dementia (HR: 2.41; 95% CI: 1.14–5.09) and all-cause dementia (HR: 2.18; 95% CI: 1.37–3.46), and the HRs were higher than that of each factor alone. Conclusions Our data indicates that type 2 diabetes is associated with increased incidence of dementia in older population, and particularly with Alzheimer's disease. The association between diabetes and dementia was attenuated after accounting for competing risk of mortality but remained strong. Carrying the APOE e4 genotype further increases the risk of dementia in type 2 diabetes patients, especially for Alzheimer's disease.

Submerged anaerobic membrane bioreactor (SAnMBR) technology was studied for kraft evaporator condensate treatment at 37 +/- 1 degrees C over a period of 9 months. Under tested organic loading rates of 1-24 kg COD/m3/day, a chemical oxygen demand (COD) removal efficiency of 93-99% was achieved with a methane production rate of 0.35 +/- 0.05 L methane/g COD removed and a methane content of 80-90% in produced biogas. Bubbling of recycled biogas was effective for in-situ membrane cleaning, depending on the biogas sparging rate used. The membrane critical flux increased and the membrane fouling rate decreased with an increase in the biogas sparging rate. The scanning electron microscopy images showed membrane pore clogging was not significant and sludge cake formation on the membrane surface was the dominant mechanism of membrane fouling. The results suggest that the SAnMBR is a promising technology for energy recovery from kraft evaporator condensate.

Laser Induced Thermoelectric Voltage (LITV) effect was observed for the first time in Pb(Zr0.3Ti0.7)O3(PZT) ferroelectric thin films grown on LaSrAlTaO3(LSATO), LaAlO3(LAO) and SrTiO3(STO) single crystal vicinal cut substrates by pulsed laser deposition (PLD). LITV signals increase linearly with the single-pulse laser energy for c -axis orientated thin film. Such a linear relationship does not hold for a -axis orientated thin film. The result shows that the LITV effect in PZT thin film is originated from the atomic layer thermopile effect, in which anisotropy of Seebeck coefficient plays an important role.

Two submerged anaerobic membrane bioreactors (SAnMBRs) (thermophilic vs. mesophilic) were operated for a period of 3.5 months with kraft evaporator condensate at a feed chemical oxygen demand of 10,000 mg/L. The results show that the filtration behavior of the two systems was significantly different. The filtration resistance in the thermophilic SAnMBR was about 5-10 times higher than that of the mesophilic system when operated under similar hydrodynamic conditions. Comparison of sludge properties and cake layer structure from the two systems was made to elucidate major factors governing the different filtration characteristics. There were more soluble microbial products (SMP) and biopolymer clusters (BPC) produced and a larger portion of fine flocs (

Taiyuan, the capital of Shanxi province, China, is one of the most polluted cities in the world. To characterize the ambient particulate pollution, samples of particulates with aerodynamic diameter less than 10 microm (PM(10)) were collected during a 6-day campaign. Individual particles were analyzed by Scanning Electron Microscope with Energy-Dispersive Spectrometer (SEM-EDS) to determine their chemical composition. Meanwhile, photomicrographs were obtained from SEM to aid in particles' source identification. The lumped data from SEM-EDS were subjected to hierarchical cluster analysis (HCA) to sort out particle types chemically. HCA combined with SEM photomicrographs allowed us to identify 20 different particle types, namely (in order of particle frequency), soil/fly ash particles, coal-burning, sulfur-rich, and iron-rich particles, gypsum, syngenite, quartz, cement, silicon sulfide, siliconferro alloy, calcium-rich particles, ferrochromium alloy, ammonium sulfate and chloride, iron-zinc, ammonium chloride, molybdenum-rich, potassium sulfate, dolomite, lead sulfate, and copper-rich particles. Their possible origins and pathways are suggested. The majority of the particles seem to originate from coal combustion, which conforms to Taiyuan's industrial structure.

The conditions for the optimal non-reciprocal operation of longitudinally magnetised ferrite-coupled line (FCL) are obtained for the first time from the scattering-matrix treatment, and the necessary conditions for the multicomponent reciprocal network joint with a FCL section to be a circulator are specified. Using these optimal conditions, the minimum length of the FCL is also found. A self-biasing circulator with the minimum length of FCL at millimetre-wave frequency is reported and its scattering characteristics are simulated and discussed.

The issue of deposited carbon (DC) on a reactor wall during the producing of acetylene by the coal/arc plasma process is a potential obstacle for the industrialization process. The formation mechanism of DC is very difficult to reveal because the high complexity of coals and the volatile matter. Combining with quenching technique, the methane, liquid petroleum gas and benzene were employed as the model materials to roughly act as the light gas, chain and aromatic subcomponents of volatile matter, and then the reasonable formation mechanism of DC was subtly speculated accordingly.

Rice straw represents a significant energy source for ruminant animals, and fibers and lignin contents of rice straw are negatively related to intake potential of forages. For improvement of the digestibility of rice straw, it is necessary to understand the genetic basis of the related traits. In present study, mapping of quantitative trait loci (QTL) for acid detergent fiber (ADF), neutral detergent fiber (NDF), and acid detergent lignin (ADL) was carried out using a doubled haploid (DH) population derived from a cross between indica variety Zai-Ye-Qing 8 (ZYQ8) and japonica variety Jing-Xi 17 (JX17). The results indicated that all three parameters were continuously distributed among the DH lines, but many DH lines showed transgressive segregation for all the three traits. A total of three main-effect QTLs were identified for ADF and ADL, two of which, qADF-9 and qADL-9, shared the same region on chromosome 9. These two main-effect QTLs explained more than 20% of the total phenotypic variations, whereas the other QTL, qADF-5, explained 12.8% of the total phenotypic variation for ADF. In addition, another two epistatic QTLs, qADF-2 and qADF-3 could explain 17.6% of the total variations. Thus, we concluded that both main-effects and epistatic QTLs were important in controlling the genetic basis of ADF.

The development of separate flood frequency distributions for different sub-seasons within a year can be useful for protection, storage and utilization of flood flows for the reservoir operation management. This paper applies conventional statistical method, fractal method and the mixed Von Mises distribution to the separation of flood sub-seasons for inflows to Hongfeng Reservoir in China. Design floods are found for different sub-seasons, along with flood control levels for flood regulation. The flood season is divided into four sub-seasons using the fractal method: the pre-rainy season (May), main-flood season (June and July), late-flood season I (August) and late-flood season II (September). The mixed Von Mises distribution method accounts for the general flood pattern and combines August and September as one late-flood season, for three sub-seasons with different frequency distributions. The flood regulation calculation results show little difference between the control water levels in August and September, so the two can be combined into one period.

Orf is a severe infectious disease of sheep and goats caused by orf virus (ORFV). To investigate the role of ORF119 gene of ORFV, we constructed ORFV with deleted ORF119 gene and LacZ as reporter gene (ORFV-Δ119-LacZ) via homologous recombination. The results showed that wild-type ORF-SHZ1 and ORFV-Δ119-LacZ deletion viruses replicated in Vero cells to similar titers. Relative transcriptional levels of virulence genes OVIFNR, GIF, VEGF and VIL-10 of ORFV-Δ119-LacZ deletion virus were slightly but not significantly lower after 24 hr compared with the wtORF-SHZ1 virus. In vivo experiments showed that 2-month-old lambs inoculated with ORFV-Δ119-LacZ deletion virus exhibited a similar total clinical score compared with those inoculated with wtORF-SHZ1 virus. Based on these results, we conclude that deletion of the ORF119 gene has no significant effect on ORFV replication and virulence.

The microstructural change of directionally solidified nickel-base superalloy which was aged at 900 °C for 1500 hours and tensile behavior at different temperatures were investigated by scanning electron microscope (SEM) and transmission electron microscope (TEM). γ′ phase of the alloy coarsens and rafts in the course of aged treatment. The driving force of rafting is the decrease of interface energy and elastic strain energy. The stress of aged alloy increases slightly with the testing temperature. This arises from a few dislocations shearing the γ′ precipitates. There is a peak stress value at 760 °C, which is attributed to the high strength of the γ′ phase, the homogeneous deformation structure, and dislocation-γ′ precipitate and dislocation–dislocation interactions. The stress then decreases rapidly with increased temperature. The low stress of the γ′ phase and γ′ rafting at high temperature contribute to the drop of alloy strength. The change of elongation is inverse to that of the stress.

In chaotic cryptosystems, it is recognized that using (very) high dimensional chaotic attractors for encrypting a given message may improve the privacy of chaotic encoding. In this paper, we study a kind of hyperchaotic systems by using some classical methods. The results show that besides the high dimension, the sub-Nyquist sampling interval (SI) is also an important factor that can improve the security of the chaotic cryptosystems. We use the method of time series analysis to verify the results.

Optimal pricing for real and reactive power is a very important issue in a deregulation environment. This paper summarises the optimal pricing problem as an extended optimal power flow problem. Then, spot prices are decomposed into different components reflecting various ancillary services. The derivation of the proposed decomposition model is described in detail. Primary-Dual Interior Point method is applied to avoid ‘go’ ‘no go’ gauge. In addition, the proposed approach can be extended to cater for other types of ancillary services.

Highly c-axis oriented MgB2 thin films with T-c(onset) of 39.6 K were fabricated by magnesium diffusing into pulsed laser deposited boron precursors. Estimation of critical current density J(c), using hysteresis loops and the Bean model, gave the value of 10(7) A/cm(2) (15 K, 0 T), which is one of the highest values ever reported. The X-ray photoemission spectra of the MgB2 thin film revealed the binding energy of Mg 2p and B 1s are at 49.4 and 186.9 eV, respectively. The Raman spectra showed a typical broad band centered at 620 cm(-1) with shoulders at 294, 410 and 730 cm(-1) respectively. The dominant band at 620 cm(-1) is interpreted as the first-order Raman response from the E-2g phonon of MgB2 and the other three bands are properly originated from the phone density of states in MgB2. (C) 2003 Elsevier Science B.V. All rights reserved.

Evolution of the ion temperature gradient parameter (ηi) has been studied in JT-60U reverse shear (RS) discharges experimentally. The ηi(r,t) behaviours for RS with and without internal transport barrier (ITB) discharges were observed, where the ITB appeared as steep gradients in the ion temperature profile, the electron density and temperature profiles. The relationship between the electron density scale length (Lne) and the ion temperature scale length (LTi) for different heating methods (NBI only and NB{} + {}ICRF) in RS discharges was compared with each other. It was observed that ηi is a key parameter to characterize ITB formation for the two cases. Kinetic stability for the toroidal drift-type modes (s

Soluble fluoro-polyimides have been synthesized by reacting of a fluorine-containing aromatic diamine, 1,3-bis(4-amino-2-trifluoromethylphenoxy) benzene(diamine 3), with aromatic dianhydrides to yield poly(amic acid)s which were then cyclized to yield polyimide by either thermal or chemical imidization method. The new tri-aromatic ring diamine, with trifluoromethyl groups at β position of amine group and bridged by ether bonds, was obtained by reduction of the corresponding dinitro-compound which was synthesized by coupling of 2-chloro-5-nitro-1-trifluoromethylbenzene with 1,3-hydroquinone in presence of strong base. Homogeneous and stable polyimide solutions with >12–15 wt.% of solid content were obtained. High quality and purity polyimide films have been prepared which exhibited excellent thermal stability, low moisture absorption and high hygrothermal stability.

Lower hybrid wave (LHW) heating has been investigated in the HT-7 superconducting tokamak. It has been observed that the plasma performance is obviously enhanced by LHW heating. The ion temperature was increased by 0.4 keV and the electron temperature by 0.3 keV. Meanwhile the central line-averaged electron density was increased from 1×1019 to 2.6×1019 m-3. The high-energy ion tail produced by the LHW was observed from the charge-exchange spectra measured by neutral particle analysis. An ion heating efficiency of (2-3) ×1013 eV kW-1 cm-3 was obtained in the experiments. The evolution of the profiles of ion temperature shows clearly an off-axis ion heating by LHW, which is in agreement with code simulations.

Ion Bernstein wave (IBW) heating has been investigated in the HT-7 superconducting tokamak. Electron heating mode was concentrated on deuterium plasma with an injecting power to 320?kW. The bulk electron temperature showed a significant rise with a heating factor, ?Te?ne/PRF, up to 9.4?eV?1013?cm-3?kW-1. The direct electron heating via electron Landau damping from IBW has been demonstrated after intensive RF wall conditioning. Both on-axis and off-axis electron heating were obtained. Electron temperature profile was modified by IBW under different plasma conditions. Edge density showed no sharp drop during IBW heating. Plasma density and temperature remained almost unchanged in front of antenna. But edge temperature and density inside of plasma visibly increased and their profiles became steeper. Particle confinement improvement was observed by IBW.

A new boronization technique focusing on the needs of the future large superconducting device has been developed in HT-7 tokamak. The first try on a tokamak gave very promising results. A fine homogeneous and hard a-B/C:H film was produced by a pulse ion cyclotron resonance frequency plasma. The film shows high adhesion, high thickness and longer lifetime. The ratio of B/C is about 3 up to a depth of 280 nm. X-ray photoelectron spectroscopy analysis shows that the B–B, B–C, C–C, C–O, and B–O bonds were formed during the boronization. The oxygen content in the film increases from 15% to 25% after 250 serious discharges, which demonstrated the strong oxygen gettering by the film. Good uniformity of the film in both toroidal and poloidal directions has been obtained by using long antenna on the high field side. The recycling of hydrogen was easily controlled by using helium rf discharge after boronization, and very strong wall pumping was observed. Plasma performance was significantly improved after boroniza...

An effective optimal spinning reserve allocation (OSRA) method is proposed in this paper using Optimal Power Flow (OPF). It enables optimal allocation of spinning reserve and load curtailment incorporating full AC network constraints and dynamic restriction on generation such as ramp-rate constraints. A Primal-Dual Interior Point (PDIP) method, which can efficiently handle both equality constraints and inequality constraints, is employed to solve the formulated dynamic OPF problem. In this model, spinning reserve and load curtailment constraints impose an interdependency between the generation output of units which usually are separable in conventional Newton OPF. A decomposition algorithm is therefore derived to handle the interdependency so that the constraint matrix of generation and that of network can be handled separately by slightly changing the entries of Hessian matrix. Therefore, the proposed method is not only still able to utilize the elegant super sparsity technique of Newton method, but also...

The density profiles were measured in the Hefei tokamak-7 (HT-7) [World Survey of Activities in Controlled Fusion Research, Nuclear Fusion Special Supplement (International Atomic Energy Agency, Vienna, 1997), p. 61] ohmic discharges by means of a new multichannel far-infrared (FIR) laser interferometer. The progress on the extension of the HT-7 ohmic discharge operation region was introduced. The experiment results at the density limit, the multifaceted asymmetric radiation from the edge (MARFE) phenomena, the rf (radio frequency) boronization experiments, and the fueling efficiency studies were reported. The plasma physics in the molecular beam injection (MBI), the pellet injection (PI), and the gas puffing (GP) fueling experiments was studied and discussed.

Multifaceted asymmetric radiation from the edge (MARFE) phenomena on the HT-7 superconducting tokamak are summarized in this paper. The best correlation has been found between the total input ohmic power and the product of the edge line average density and Z eff . The occurrence of MARFEs are strongly correlated with impurity density, and always occur at Z eff =3–8 ohmic discharges. In the HT-7 tokamak high Z eff discharges, it is found that the MARFEs usually occur at values of Z eff 1/2 ρ in the range of 0.5–0.7, where ρ =π a 2 n e / I p (10 20 MA −1 m −1 ). In the case of good wall condition ( Z eff =1–2), the onset of MARFEs have not been observed before reaching the Greenwald density limit on the HT-7. Improved confinement mode induced by a MARFE is observed, and it is maintained for about 40 ms. MARFE cools the plasma edge, and the electron density profile is observed to become more narrow and peaked.

It is now well known that the room temperature tensile yield strength (σy), fracture strength (σf), and ductility (δ) of TiAl alloys increase with decreasing the colony size (d) of the fully lamellar (FL) structure. Therefore searching a cost-effective approach to refine the coarse FL structure becomes critical to the engineering application of this material. In this study, we report our recent observation that, merely by rapid heat treatment, a FL structure with d=500 μm in a TiAl alloy of Ti–48Al–2Cr (at%) could be refined to a FL structure with d being as fine as 10 μm. No thermomechanical processing such as canned forging and hot extrusion, as done in previous studies, was required. Mechanical testing in tension shows that with the refinement from 500 to 10 μm, the room temperature yield strength increased from 330 to 610 MPa, fracture strength from 415 to 825 MPa and ductility from 0.7 to 3.3%, although the fracture toughness decreased only slightly from 24 to 19 MPa m1/2.

The first full-wave normal-mode analysis of ferrite coupled lines (FCLs) magnetized in the longitudinal direction is presented in this paper. It is found that the tangential and axial components of the guided electric and magnetic fields undergo a different change in the process of reversing the direction of magnetization. These changes cause the same input wave to decompose into the eigenmodes of the FCL differently for different direction of magnetization and, consequently, cause the nonreciprocal behavior of the magnetized FCL. A new optimum nonreciprocal operation condition is obtained, and applications to FCL circulators built on microstrips and striplines are discussed.

An investigation of the evolution to localised states of various input spin distributions is presented, for a linear ferromagnetic chain with on-site anisotropy. A detailed study of the accessibility of bright solitary stationary states from a given input spin distribution is presented from both a discrete and a continuum point of view. Both nonlinear Schrodinger and modified regimes are encountered. Dark solitons, modulation instability for the discrete and continuum equations, a full discussion of the class of continuum solutions and a Lagrangian analysis are all presented here.

In this paper, an integrated optimal spot pricing model is presented first. The proposed model includes the detailed derivation of optimal nodal specific real-time prices for active and reactive powers, and the method to decompose them into different components corresponding to generation, loss, and many selected ancillary services such as spinning reserve, voltage control and security control. The features of the proposed model are discussed in relationship to existing pricing models and classical economic dispatch. The model is then implemented by modifying existing Newton OPF methods through interior point algorithms, which can effectively avoid "go" "no go" gauge (i.e. highly volatile) in the calculation of spot prices. Case studies on 5-bus and IEEE 30-bus systems are reported to illustrate the proposed method.

The dynamics of solitary waves in second-order nonlinear materials are discussed using a multiple scales model. After making some comments on the applicability of other perturbation techniques the multiple scales ap- proach is developed with a view to setting up a line of approach that, in principle, permits radiative effects to be modelled. After a closure condi- tion is applied, equations for the evolution of dynamical variables are de- veloped. Applications of these equations to loss and interactions are pre- sented together with confirmation from numerical simulations. It is empha- sised that the method is capable of extension to higher-order perturbations and, hence, into the solitary wave fusion region. The established interpreta- tion of quasi-phase-matching fluctuations as loss is discussed and the simple problems of soliton (solitary wave) pair interactions in both loss-free and lossy media are analysed.

AlN films grown by either organometallic vapor phase epitaxy (OMVPE) or pulsed laser deposition (PLD) can be used to encapsulate SiC when heated in an argon atmosphere at temperatures at least as high as 1600 °C for times at least as long as 30 min. The coverage of the AlN remains complete and the AlN/SiC interface remains abrupt as determined by Auger electron spectroscopy. However, considerable atomic movement occurs in the AlN at 1600 °C, and holes can form in it as the film agglomerates if there are large variations in the film thickness. Also, the SiC polytype near the surface can in some instances be changed possibly by the stress generated by the epitaxial AlN film. Using x-ray diffraction measurements, we also found that, during the 1600 °C anneal, grains with nonbasal plane orientations tended to grow at the expense of those with basal plane orientations in the OMVPE films, whereas grains with only the basal plane orientation tended to grow in the PLD films. However, there is no indication that t...

The four vector equations, appropriate to a mixed type I–type II second-harmonic generation, in a thin planar waveguide, made from a second-order non-linear material, are solved, both approximately and exactly. The solutions are then used to generate possible applications. In this investigation, both the fundamental and the second-harmonic waves have two transverse field components. It is shown that, by controlling the ratio of the components of the fundamental wave, one component of the second-harmonic wave can be rigorously controlled, and even switched off. The ratio of the harmonic field components depends strongly upon the polarization angle of the fundamental wave, with the extinction angle depending strongly upon the phase mismatch parameter. In a second application, an aperture is placed at the output and it is shown that if approximate stationary states are used as an input to a quadratically non-linear medium, then varying the angle of incidence of two input beams produces an excellent output control. A numerical demonstration is given in which a switch from 80% of the input energy arriving at the output port to less than 3% is readily achievable.

Analytical and numerical solutions that describe the coupling between bright and dark spatial solitons, located in separate planar waveguides are presented. The analytical theory rests upon a well-known variational approach and it is shown to be in good qualitative/semi-quantitative agreement with the exact numerical solutions of the coupled equations of the problem. By manipulating the soliton ‘masses’, through the input power, interesting trajectories for the solitons can be selected. Indeed, these trajectories are shown to possess behaviour patterns that qualify as the first steps in a design of an all-optical scanner. At all stages, the variational solutions are thoroughly checked by the numerical simulations and found to have excellent predictive qualities.

Modulation instability, induced by the simultaneous propagation of two magnetostatic spin waves in ferromagnetic films, has been experimentally observed for the first time. The effect is caused by cross-phase modulation and the spectra of transmitted waves contains sidebands, symmetrically positioned either side of the carrier frequency. They appear as the wave power reaches a threshold value, and disappear when only one wave is present. This is the signature of cross-phase modulation. The dependence of the modulation frequency upon the wave power and frequency is reported and a theoretical explanation of the observed phenomenon, using nonlinear Schrddinger coupled equations, is presented.