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Two different bifurcation scenarios, one is novel and the other is relatively simpler, in the transition procedures of neural firing patterns are studied in biological experiments on a neural pacemaker by adjusting two parameters. The experimental observations are simulated with a relevant theoretical model neuron. The deterministic non-periodic firing pattern lying within the novel bifurcation scenario is suggested to be a new case of chaos, which has not been observed in previous neurodynamical experiments.

High-spin states of 160Tm are studied by the 146Nd(19F, 5n) reaction at a beam energy of 102 MeV. The previously known πh11/2 ⊕νi13/2 yrast band and πh11/2 ⊕νh9/2 side band are confirmed. The level scheme is enriched and more low-lying levels are observed. A new side band is observed and assigned as the favoured signature partner of πd3/2 ⊕νi13/2. The spin of this band is assigned with the energy level systematics. It is pointed out that the B(M1)/B(E2) ratios increase rapidly at the high frequency approaching the second crossing in the πh11/2 ⊕νi13/2 band, which is closely related to the alignment gain of the aligned i13/2 quasineutron.

A novel phosphorescent organic white-light-emitting device (WOLED) with configuration of ITO/NPB/CBP:TBPe:rubrene/Zn(BTZ)2:Ir(piq)2(acac)/Zn(BTZ)2/Mg:Ag is fabricated successfully, where the phosphorescent dye bis (1-(phenyl)isoquinoline) iridium (III) acetylanetonate (Ir(piq)2(acac)) doped into bis-(2-(2-hydroxyphenyl) benzothiazole)zinc (Zn(BTZ)2) (greenish-blue emitting material with electron transport character) as the red emitting layer, and fluorescent dye 2,5,8,11-tetra-tertbutylperylene (TBPe) and 5,6,11,12-tetraphenyl-naphthacene (rubrene) together doped into 4,4'-N,N'-dicarbazole-biphenyl (CBP) (ambipolar conductivity material) as the blue-orange emitting layer, respectively. The two emitting layers are sandwiched between the hole-transport layer N,N'-biphenyl-N, N'-bis (1-naphthyl)-(1,1'-biphenyl)-4,4'-diamine (NPB) and electron-transport layer (Zn(BTZ)2). The optimum device turns on at the driving voltage of 4.5 V. A maximum external quantum efficiency of 1.53% and brightness 15000 cd/m2 are presented. The best point of the Commission Internationale de l'Eclairage (CIE) coordinates locates at (0.335, 0.338) at about 13 V. Moreover, we also discuss how to achieve the bright pure white light through optimizing the doping concentration of each dye from the viewpoint of energy transfer process.

Tip-enhanced near-field fluorescence and topography characterization of a single nanometre fluorophore is conducted by using an apertureless scanning near-field microscopy system. A fluorophore with size 80 nm is mapped with a spatial resolution of 10 nm. The corresponding near-field fluorescence data shows significant signal enhancement due to the apertureless tip-enhanced effect. With the nanometre spatial resolution capability and nanometre local tip-enhanced effect, the apertureless tip-enhanced scanning near-field microscopy may be further used to characterize a single molecule by realizing the local near-field spectrum assignment corresponding to topography at nanometre scale.

Cr-doped InAs self-organized diluted magnetic quantum dots (QDs) are grown by low-temperature molecular-beam epitaxy, Magnetic measurements reveal that the Curie temperature of all the InAs:Cr QDs layers with Cr/In flux ratio changing from 0.026 to 0.18 is beyond 400 K. High-resolution cross sectional transmission electron microscopy images indicate that InAs:Cr QDs are of the zincblende structure. Possible origins responsible for the high Curie temperature are discussed.

Both diffusion and epidemic are well studied in the stochastic systems and complex networks, respectively. Here we combine these two fields and study epidemic diffusion in complex networks. Instead of studying the threshold of infection, which was focused on in previous works, we focus on the diffusion behaviour. We find that the epidemic diffusion in a complex network is an anomalous superdiffusion with varying diffusion exponent γ and that γ is influenced seriously by the network structure, such as the clustering coefficient and the degree distribution. Numerical simulations have confirmed the theoretical predictions.

Zincblende CrSb (zb-CrSb) layers with room-temperature ferromagnetism have been grown on relaxed and strained (In,Ga)As buffer layers epitaxially prepared on (001) GaAs substrates by molecular-beam epitaxy. The structural characterizations of CrSb layers fabricated under the two cases are studied by using synchrotron grazing incidence x-ray diffraction (GID). The results of GID experiments indicate that no sign of second phase exists in all the zb-CrSb layers. Superconducting quantum interference device measurements demonstrate that the thickness of zb-CrSb layers grown on both relaxed and strained (In,Ga)As buffer layers can be increased to similar to 12 monolayers (similar to 3.6nm), compared to similar to 3 monolayers (similar to 1nm) on GaAs directly.

High-spin level structure of doubly odd nucleus 140Pr has been investigated via the 130Te(14N,4n)140Pr reaction at beam energies from 55 to 65 MeV. Measurements of γ-ray excitation functions, γ-ray singles and γ-γ-t coincidences were performed with twelve BGO(AC)HPGe detectors. The level scheme of 140Pr, including 27 new levels and 42 new γ rays, has been established for the first time. The level structure is compared with those in the neighbouring odd–odd nuclei, and interpreted qualitatively.

The Portevin–Le Chatelier (PLC) effect with typical temporal instabilities in the recorded stress is closely associated with local inhomogeneities of deformation. By employing the dynamic digital speckle pattern interferometry technology, the characterizations for the PLC deformation bands of type A (continuous propagation along the specimen), type B (``hopping'' propagation along the specimen) and type C (random nucleation in the sample) were distinctly clarified. The corresponding positions of deformation bands were traced throughout the whole tensile process. By systemic experiments, the range of the applied strain rates for each type of bands existing was investigated respectively. The evolution of the band velocity (for types A and B) was also statistically investigated and qualitatively interpreted.

High spin states in 80Rb were studied via the 65Cu+19F, 66Zn+18O and 68Zn+16O reactions. The 75-MeV 19F, 76-MeV 18O and 80-MeV 16O beams were provided by the CIAE HI-13 Tandem accelerator and the JAERI Tandem accelerator. The prompt γ-γ coincidence and the directional correlation from oriented nuclei (DCO) were measured by the detector arrays in CIAE and JAERI. Twenty-three new states with 28 new transitions have been assigned to 80Rb. The states were observed up to spins of 20+ and 22− in the α = 0 branch for the positive and negative parity yrast bands respectively. The negative parity non-yrast bands were significantly extended up to spins of 22− and 15−. The band crossings with frequencies 0.51 MeV and 0.61 MeV in the α = 0 cascade were observed for the first time. The signature splitting was observed in both negative parity bands. The signature inversions at spins of about 7 and 15 were observed.

Effects of oxygen deficiency on the magnetic and transport properties of La2/3Ba1/3MnO3-δ polycrystalline perovskites have been investigated. As the nonstoichiometry parameter δ increases from 0.00 to 0.10, the lattice parameters at room temperature increase from 3.892(3) A to 3.909(3) A, the resistivity increases and the ferromagnetic ordering transition temperature shifts from 337 K to 268 K. A large magnetoresistance effect with -Δρ/ρ0 of about 30% (955 kA/m, δ = 0.10) and a large magnetic entropy change of about 2.7 J/kgK (796 kA/m, δ = 0.00) is obtained in polycrystalline La2/3Ba1/3MnO3-δ. The enhanced magnetoresistance effect at low temperature would be related to the grain boundaries of the polycrystalline samples.

High spin states of the odd proton-nucleus 169Ta have been populated in the reaction 155Gd(19F,5n) with beam energies of 97 MeV. Rotational band based on d3/2 proton 1/2[411] Nilsson state has been pushed up to 39/2+ in the α = 1/2 decay sequence. Its signature partner, the α = -1/2 decay sequence with four link transitions has been established and 1/2[411] band in 169Ta was reassigned to be a semi-decoupled band. The systematics of the signature splitting in the K = 1/2 bands in the rear-earth region and the accidental degeneracy conclusion given by the angular projection shell model were discussed.

Internal friction of nanocrystalline nickel is investigated by mechanical spectroscopy from 360 K to 120 K. Two relaxation peaks are found when nanocrystalline nickel is bent up to 10% strain at room temperature and fast cooling. However, these two peaks disappear when the sample is annealed at room temperature in vacuum for ten days. The occurrence and disappearance of the two relaxation peaks can be explained by the interactions of partial dislocations and point defects in nanocrystalline materials.

The g-factors of the positive parity rotational states up to spin I = 8+ for the ground state band in even-even nuclei 82Sr have been measured by a transient-magnetic-field ion implantation perturbed angular distribution method. The experimentally measured g-factors increase with the increasing spin along the band and show that the g9/2 proton aligns only and the alignment starts from I = 6+. The measured g-factors also indicate that the nuclei 82Sr gain their spins by the quasi-proton alignment at higher spin.

Nitrogen-doped ZnO (ZnO:N) films are prepared by thermal oxidation of sputtered Zn3N2 layers on Al2O3 substrates. The correlation between the structural and optical properties of ZnO:N films and annealing temperatures is investigated. X-ray diffraction result demonstrates that the as-sputtered Zn3N2 films are transformed into ZnO:N films after annealing above 600° C. X-ray photoelectron spectroscopy reveals that nitrogen has two chemical states in the ZnO:N films: the NO acceptor and the double donor (N2)O. Due to the No acceptor, the hole concentration in the film annealed at 700° C is predicted to be highest, which is also confirmed by Hall effect measurement. In addition, the temperature dependent photoluminescence spectra allow to calculate the nitrogen acceptor binding energy.

We present a new substrate-free bimaterial cantilever array made of SiNx and Au for an uncooled micro-optomechanical infrared imaging device. Each cantilever element has an optimized deformation magnification structure. A 160 × 160 array with a 120 μm × 120 μm pitch is fabricated and an optical readout is used to collectively measure deflections of all microcantilevers in the array. Thermal images of room-temperature objects with higher spatial resolution have been obtained and the noise-equivalent temperature difference of the fabricated focal plane arrays is given statistically and is measured to be about 270 mK.

A new one-dimensional phenomenological model based on the dynamic strain aging mechanism is developed. In order to account for the elastic shrinkage induced by the Portevin–Le Chatelier effect, elastic deformation is considered under the boundary conditions of the present model. The simulated results are found to be in good agreement with the experimental observations.

We report on a white organic light emitting device (OLED) with a single light emitting layer consisting of a greenish-white emitting host bis-(2-(2-hydroxyphenyl) benzothiazole)zinc (Zn(BTZ)2) and an orange-red dopant 5,6,11,12-tetraphenylnaphthacene (rubrene). The Commission Internationale De L'Eclairage (CIE) coordinates, external quantum efficiency, and brightness of the white OLED are (0.341, 0.334), 0.63% and 4000 Cd/m2 at the bias of 20 V, respectively. Pure red-green-blue (RGB) emissions have been successfully achieved from the white OLED combined well with several built-in optical colour filters (CFs). The CIE coordinates of the white mixture calculated in theory are very close to the coordinates of the white mixture which recorded with spectrophotometer in practice.

Deformation twinning is evidenced by transmission electron microscopy examinations in electrodeposited nanocrystalline (nc) Ni with mean grain size 25 nm upon cryogenic rolling. Two twinning mechanisms are confirmed to operate in nc grains, i.e. heterogeneous formation via emission of partial dislocations from the grain boundary and homogeneous nucleation through dynamic overlapping of stacking faults, with the former being determined as the most proficient. Deformation twinning in nc Ni may be well interpreted in terms of molecular dynamics simulation based on generalized planar fault energy curves.

The microstructure characteristic of the cold-rolled deformed nanocrystalline nickel metal is studied by transmission electron microscopy. The results show that there are step structures nearby the grain boundary (GB), and the contrast of stress field in front of the step corresponds to the step in the shape. It is indicated that the interaction between twins and dislocations is not a necessary condition to realizing the deformation. In the later stage of the deformation when the grain size becomes about 100nm, the deformation can depend upon the moving of the boundary of the stack faults (SFs) which result from the partial dislocations emitted from GBs. However, when the size of SFs grows up, the local internal stress which is in front of the step gradually becomes higher. When this stress reaches a critical value which stops the gliding of the partial dislocations, the SFs will stop to grow up and leave a step structure behind.

We present three kinds of organic light-emitting devices (OLED) fabricated to achieve the emission of bright and pure white light. Device A, with a double-layered structure using 2-(2-hydroxyphenyl) benzothiazole (HBT) and poly (N-vinylcarbazole) (PVK) as the emitting layer (EML) and the hole transport layer (HTL) respectively, could realize the blue-green light emission. Bis-(2-(2-hydroxyphenyl) benzothiazole)zinc (Zn(BTZ)2), synthesized with zinc acetate dihydrate and HBT to form a complex, is used as main EMLs in a similar structure to fabricate devices B and C. Bright and pure white light emissions can be obtained from device C which was fabricated with a green-white emitting host Zn(BTZ)2 and red dopant 5,6,11,12-tetraphenylnaphthacene (rubrene). The maximum quantum efficiency of device C could reach 0.63%, and the corresponding brightness and CIE coordinates were 4000 cd/m2 and (x = 0.341, y = 0.334) at the driving voltage of 20 V.

The g-factors of the positive parity rotational levels up to spin I = 41/2+ in 83Y have been measured by a transient-magnetic-field ion implantation perturbed angular distribution method. The experimentally measured g-factors show the g9/2 proton alignment followed by the g9/2 neutron alignment. The measured g-factors are in good agreement with the results calculated by an empirical formula based on the cranking shell model.

We investigate effects of annealing on magnetic properties of a thick (Ga,Mn)As layer, and find a dramatic increase of the Curie temperature from 65 to 115 K by postgrowth annealing for a 500-nm (Ga,Mn)As layer. Auger electron spectroscopy measurements suggest that the increase of the Curie temperature is mainly due to diffusion of Mn interstitial to the free surface. The double-crystal x-ray diffraction patterns show that the lattice constant of (Ga,Mn)As decreases with increasing annealing temperature. As a result, the annealing induced reduction of the lattice constant is mainly attributed to removal of Mn interstitial.

Excited states in 142Pm are investigated via the 128Te(19F, 5n)142Pm reaction at beam energies from 75 to 95 MeV by using techniques of in-beam γ-ray spectroscopy. Measurements of γ-ray excitation function, X–γ and γ–γ–t coincidences are performed with 10 BGO(AC)HPGe detectors. Decay of the previously known 67-μs isomer in 142Pm is observed and added into the new level scheme. This isomer is definitely placed at the excitation energy of 2828.5 keV. The spin of this isomer is suggested to be 13 according to the measured γ-ray anisotropies.

The mechanism of the critical strain of serrated yielding is studied via tension tests at various strain rates. Before the critical strain, it is deduced that dislocations are not pinned at high strain rates, and dislocations at low strain rates are pinned but cannot escape. The critical strain depends on the first pinning process at high strain rates and on the first unpinning process at low strain rates. The calculated results based on the two criteria are in good consistency with the experiment.

We develop an uncooled infrared imaging device that contains a SiN–Au bimaterial micro-cantilever arrays detector and an optical read-out section. The detector converts the incident infrared radiation to the cantilever inclination angles, and the optical read-out section converts these angles directly to a visible image through an optical filtering operation to the spectra of the cantilever arrays with a knife-edge filter. The present results with the 140×98 cantilever arrays and the 8-bit A/D quantizer suggest that the objects at the temperature of 250°C at the distance as far as 1 m can be detected and the noise-equivalent temperature difference (NETD) of the device is about 10 K. The further improvement of NETD is expected to approach about 14 mK with the optimized cantilever design and 12-bit quantizer.

The lifetime measurements of the high-spin states in the yrast band of 130Ce have been performed using the Doppler shift attenuation method in conjunction with the reaction 116Sn(16O,2n)130Ce at a projectile energy of 73 MeV. The reduced transition probabilities B(E2) deduced from these measurements show a great reduction in the vicinity of the backbending region. The previously reported anomalously high B(E2) value was not observed in the present experiment. This result is in agreement with theoretical prediction based on a realistic nucleon-nucleon interaction.

High-spin states in 122Ba have been investigated in the 107Ag(19F, 4n) reaction by in-beam γ-ray spectroscopic methods. The ground-state band has been observed with spin up to 20 and a negative-parity band is identified with spin state up to 19. A band-crossing in the yrast band is observed at a rotational frequency of ω≈ 0.36 MeV and, in accordance with cranked shell model calculations, is interpreted as arising from the alignment of two h11/2 protons. Strong E1 transitions between the negative-parity and the yrast bands have been observed, which are proposed as possible evidence for octupole correlations.

High spin states in 90Mo have been populated through the 59Co (35Cl,2p2n) 90Mo reaction at a beam energy of 116 MeV. Level lifetimes of the positive-parity decay sequence are measured by using the Doppler shift attenuation method. It is observed that the M1 transition strengths show a substantial enhancement at high spin. This behaviour may be related to occupation of high Ω orbitals by a pair of g9/2 protons. A deformed, oblate, shape is suggested above the 13+ state.

We report the first observations of nonlinear feature and optical bistability in n-CdHgTe at 77 K and obtained computer simulated curves, then discuss contribution due to thermal effect.

High-spin states in the odd-proton nucleus 135Pm have been investigated using the 107Ag(32S, 2p2n)135Pm reaction. Seven rotational bands have been observed in 135Pm. The yrast band based on a decoupled h11/2 proton is found to have a band crossing in ωc~0.43 MeV/. Two positive-parity bands based on the two signature components of the πg7/25/2+[413] Nilsson orbital have been observed in the main sidebands. The favoured band with (π,α) = ( + ,-1/2) has been shown to populate below the first pair of proton alignment. Both bands have shown upbend at ω1~0.26 MeV/ and ω2~0.43 MeV/. These crossing frequencies can be attributed to the decoupling of the first pair of h11/2 quasi-proton and h11/2 quasi-neutron, respectively. Four weaker bands have been observed in sidebands too. Among them, two states are possibly built on a πd5/23/2+[411] configuration. PACS: 23. 20. Lv, 25. 70. -z, 27. 60. +j

The level states of the nucleus 124Cs have been populated through the 116Sn(11B,3n) reaction at a beam energy of 45 MeV, provided by the HI-13 tandem accelerator of the China Institute of Atomic Energy. A number of low-lying states are constructed. The level states in the πh11/2⊗νg7/2 side band are extended down to lower spin by one hour. The level energies and spins in the rotational bands are determined through the establishment of various connections, which confirm the spin assignment of the yrast band in 124Cs based on excitation energy systematics. It is revealed that with the present spin assignment, the πh11/2⊗νg7/2 side band shows signature inversion at low-spin region and the inversion occurs at a spin of about 16. PACS: 21. 10. Re, 23. 20. Lv, 27. 60. +j, 29. 30. Kv

High spin states in 137Ce have been studied by using the heavy-ion induced reaction 124Sn(18O, 5n) carried out at China Institute of Atomic Energy. Partial level scheme with spin up to (43/2-), including a high spin collective rotational band observed for the first time, has been established. The collective band shows the properties similar to those oblate bands with ? ~ -60? in neighboring nuclei and probably originates from the five quasi-particle configuration ?s1/2 ? [?h11/2]2 ? ?g7/2 ? ?h11/2. The characteristics of this oblate band have been discussed.