Study on interaction between Dy（III）（NR）3 complex and herring sperm DNA by spectroscopy

The action mode between Dy（III）（NR）3 and herring sperm DNA is studied by ultraviolet-visible （UV- vis） and fluorescence spectra as well as electrochemistry. Double-reciprocal method studies show that the binding stoichiometry between Dy（III）（NR）3 and DNA is 1 ： 1, the binding constants at different temperatures are 1.15 ×10^5 L/tool at 25 ℃ and 2.09 × 105 L/mol at 35 ℃, and the corresponding I thermodynamic parameters are /krHm = 2.48 × 10^4 J/tool, ArGm ： -2.34 × 104 J/mol, ArSm = 161.7 J/（mol. K）, ArSm is the driving force in this reaction. Combined with Scatchard method and melting method, the results suggest that the interaction mode between Dy（III）（NR）3 and herring sperm DNA is intercalation fashion and groove fashion.     

Probing anomalous top-Higgs couplings at the HL-LHC via H→WW~* decay channels

We study the prospects of probing the anomalous tHq(q=u,c)couplings via SS2L or 3L signatures at the High Luminosity(HL-LHC)run of the 14 Te V CERN collider.We focus on signals of the tH associated production followed by the decay modes t→b?~+ν_?and H→W W~*,and ■ production followed by the decay modes t→b?~+ν_?and■where?=e,μ.Based on two types of H→W W~*decay topologies,one assuming the semileptonic decay mode H→W W~*→?~+νjj and the other the fully leptonic decay mode■,we perform a full simulation for signals and backgrounds.It is shown that,at the future HL-LHC,the branching ratio Br(t→uh)(Br(t→ch))can be probed to 1.17(1.56)×10~(-3)for the same-sign di-lepton channel,and to7.1×10~(-4)(1.39×10~(-3))for the 3L channel at 3σsensitivity.     

Crystal growth,spectroscopic characteristics,and Judd–Ofelt analysis of Dy:Lu_2O_3 for yellow laser

Dy:Lu_2O_3 was grown by the float-zone(Fz) method. According to the absorption spectrum, the Judd–Ofelt(JO) parameters ?_2, ?_4, and ?_6 were calculated to be 4.86 × 10~(-20) cm~2, 2.02 × 10~(-20) cm~2, and 1.76 × 10~(-20) cm~2, respectively.The emission cross-section at 574 nm corresponding to the ~4F6_(9/2)→~6H_(13/2) transition was calculated to be 0.53 × 10~(-20) cm~2.The yellow(~4F_(9/2)→~6H_(13/2) transition) to blue(~4F_(9/2)→~6H_(15/2) transition) intensity ratio ranges up to 12.9. The fluorescence lifetime of the ~4F_(9/2) energy level was measured to be 112.1 μs. These results reveal that Dy:Lu_2O_3 is a promising material for use in yellow lasers.     

Millimeter Propagation and High Confinement in Rhombus-Based Hybrid Plasmonic Waveguides

A hybrid plasmonic waveguide, consisting of two dielectric nanowires symmetrically put at the opposite corner angles of a rhombic metM, is proposed and numerically analyzed by the finite-element method. Simulations show that the present waveguide can achieve the millimeter propagation distance （1244 μm） and deep subwavelength mode area （5.5 × 10-3 μm2）, simultaneously. Compared with the previous hybrid waveguides based on cylinder nanowires or fiat films, the rhombie corner angles enable our waveguide to achieve both longer propagation distance and smaller mode area. This is due to the enhanced coupling between the dielectric guided mode in nanowires and the surface plasmon polariton mode at rhombic surface. Furthermore, the extreme confinement near the rhombic corner angles can strengthen the light-matter interaction greatly and make the present waveguide useful in many applications, such as nonlinear photonics, high-quality nanolazers and nanophotonic waveguides.     

Crystal Structure and Judd–Ofelt Analysis of Er~(3+) Doped LuAl_3(BO_3)_4 Crystal

Single crystal Er:LuAl_3(BO_3)(Er:Lu AB) is successfully grown using the top-seeded solution growth method with a K_2Mo_3O_(10) flux. The cell parameters of the grown crystal are estimated by an x-ray single crystal diffactometor and x-ray powder diffraction analysis. The result indicates that it still belongs to the space group R32. The obtained unit-cell parameters are a= 9.2793(19) ?, c= 7.210(3) ?, V= 537.65(27) ?~3, and Z=3.The absorption spectrum is measured at room temperature. The spectroscopy properties are investigated based on the Judd–Ofelt(J-O) theory, and the effective J-O parameters were calculated to be Ω_2=8.33×10~(-20),Ω_4=3.83×10~(-20), and Ω_6 =3.55×10~(-20). The emission spectra of Er:LuAB crystal at room temperature are also studied and the ~4I_(11/2)→~4I_(13/2) fluorescence around 3170 nm is observed. The emission cross section calculated by the F-L formula is 8.6×10~(-20) cm~2. These results suggest that the Er:LuAB crystal may be a promising ~3 μm laser material.     

Measurements of effective delayed neutron fraction in a fast neutron reactor using the perturbation method

A perturbation method is proposed to obtain the effective delayed neutron fraction β_(eff) of a cylindrical highly enriched uranium reactor.Based on reactivity measurements with and without a sample at a specified position using the positive period technique,the reactor reactivity perturbation △ρ of the sample in β_(eff) units is measured.Simulations of the perturbation experiments are performed using the MCNP program.The PERT card is used to provide the difference dκ of effective neutron multiplication factors with and without the sample inside the reactor.Based on the relationship between the effective multiplication factor and the reactivity,the equation β~(eff)=dκ/△ρ is derived.In this paper,the reactivity perturbations of 13 metal samples at the designable position of the reactor are measured and calculated.The average β_(eff) value of the reactor is given as 0.00645,and the standard uncertainty is 3.0%.Additionally,the perturbation experiments for β_(eff) can be used to evaluate the reliabilities of the delayed neutron parameters.This work shows that the delayed neutron data of ~(235)U and ~(238)U from G.R.Keepin's publication are more reliable than those from ENDF-B6.0.ENDF-B7.0,JENDL3.3 and CENDL2.2.     

Experimental study of noncontact ultrasonic motor with non-symmetrical electrode

We have proposed a novel noncontact ultrasonic motor based on non-symmetrical electrode driving. The configuration of this electrode and the fabrication process of rotors are presented. Its vibration characteristics are computed and analysed by using the finite element method and studied experimentally. Good agreement between them is obtained. Moreover, it is also shown that this noncontact ultrasonic motor is operated in antisymmetric radial vibration mode of $B_{21}$ mode. The maximum revolution speed for three-blade and six-blade rotors are 5100 and 3700\,r/min at an input voltage of 20V, respectively. Also, the noncontact high-speed revolution of the rotors can be realized by the parts of I, III of the electrode or II, IV of the electrode. The levitation distance between the stator and rotor is about 140$\mu $m according to the theoretical calculation and the experimental measurement.     

Transition Dipole Moment Measurements of Ultracold Photoassociated ~(85)Rb~(133)Cs Molecules by Depletion Spectroscopy

The transition dipole moments(TDMs) of ultracold85 Rb133 Cs molecules between the lowest vibrational ground level, (X~1Σ~+( v= 0, J= 1), and the two excited rovibrational levels, 2~3Π_0+(v′= 10, J′= 2) and 2~1Π_1(v′= 22,J′= 2), are measured using depletion spectroscopy. The ground-state85 Rb133 Cs molecules are formed from cold mixed component atoms via the 2~3Π_0-( v= 11, J= 0) short-range level, then detected by time-of-flight mass spectrum. A home-made external-cavity diode laser is used as the depletion laser to couple the ground level and the two excited levels. Based on the depletion spectroscopy, the corresponding TDMs are then derived to be 3.5(2)×10~(-3)eα_α and 1.6(1)×10~(-2)eα_α, respectively, where 0)(60 represents the atomic unit of electric dipole moment. The enhance of TDM with nearly a factor of 5 for the 21Π1(v′= 22, J′= 2) excited level means that it has stronger coupling with the ground level. It is meaningful to find more levels with much more strong coupling strength by the represented depletion spectroscopy to realize direct stimulated Raman adiabatic passage transfer from scattering atomic states to deeply molecular states.     

Extraction of mode attenuation coefficient from low frequency reverberation signal

A method of extracting normal mode attenuation coefficient from low frequency reverberation signal has been proposed.Pseudo-inverse normal mode filtering method is implemented to get single mode reverberation field firstly.Based on the assumption of separability of modal back-scattering matrix,effective back-scattering matrix element can be calculated using single mode average reverberation intensity.Finally,mode attenuation coefficient is extracted by comparing effective back-scattering matrix elements at different ranges.The extracted mode attenuation coefficients are used to predict sound transmission loss at the same experiment area. Results show that the predicted transmission loss agrees well with the measured data.This method avoids the difficult of treating the coupling between bottom scattering attenuation and normal mode propagation attenuation.Research on extraction of mode attenuation coefficient from low frequency reverberation signal is useful for both geoacoustic inversion and rapid underwater environment assessment.     

Measurement of interaction force between RGD-peptide and Hela cell surface by optical tweezers

Since RGD peptides (R: arginine; G: glycine; D: aspartic acid) are found to promote cell adhesion, they are modified at numerous materials surface for medical applications such as drug delivery and regenerative medicine. Peptide-cell surface interactions play a key role in the above applications. In this letter, we study the adhesion force between the RGD-coated bead and Hela cell surface by optical tweezes. The adhesion is dominated by the binding of α5β1 and RGD-peptide with higher adhesion probability and stronger adhesion strength compared with the adhesion of bare bead and cell surface. The binding force for a single α5β1 -GRGDSP pair is determined to be 16.8 pN at a loading rate of 1.5 nN/s. The unstressed off-rate is 1.65 × 10-2s-1 and the distance of transition state for the rigid binding model is 3.0 nm.     

Interaction between impurity nitrogen and tungsten： a first-principles investigation

We investigate the stability,diffusion,and impurity concentration of nitrogen in intrinsic tungsten single crystal employing a first-principles method,and find that a single nitrogen atom is energetically favourable for sitting at the octahedral interstitial site.A nitrogen atom prefers to diffuse between the two nearest neighboring octahedral interstitial sites with a diffusion barrier of 0.72 eV.The diffusion coefficient is determined as a function of temperature and expressed as D(N)=1.66×10～(-7) exp(0.72/kT).The solubility of nitrogen is estimated in intrinsic tungsten in terms of Sieverts’ law.The concentration of the nitrogen impurity is found to be 4.82×10～(-16) A～3 at a temperature of 600 K and a pressure of 1 Pa.A single nitrogen atom can easily sit in an off-vacancy-centre position close to the octahedral interstitial site.There exists a strong attraction between nitrogen and a vacancy with a large binding energy of 1.40 eV.We believe that these results can provide a good reference for the understanding of the behaviour of nitrogen in intrinsic tungsten.     

Measurement of the binding force between RAS protein and a pathologic BRAF mutant using optical tweezers

Activating mutants in rat sarcoma （RAS） and B-rapid accelerated fibrosarcoma （BRAF） are found in at least a third of cases of human tumors and melanoma; hence, numerous therapeutic treatments target this pathway. In this letter, we study the adhesion force of RAS-coated beads with BRAF-coated beads, BRAF （A246P） mutant-coated beads, and GST-coated beads using optical tweezers. One full and two fractional RAS BRAF specific binding modes are identified using the rupture force distribution. The koff（0） of the full binding mode in RAS BRAF is 3.71×10^-4/s and 1.16×10^-4s^-1 in RAS BRAF （A246P）, whereas the Xb is around 3×10^-10 m in both groups.     

Bubble Formation in Apatite Structures by He-Ion Irradiation at High Temperature

Apatite ceramics Ca_(10)(PO_4)_6 X_2(X=F,OH) were prepared by the standard solid state sintering method and irradiated with He ions under a fluence of 5×10~(16) ions/cm~2 at 450℃.Irradiation induced formation and growth of the He bubbles were observed by a transmission electron microscope.Hydroxyapatite Ca_(10)(PO_4)_6(OH)_2 and fluoroapatite Ca_(10)(PO_4)_6 F_2 with different He bubble morphologies indicate the influence of OH~-/F~-substitution on the He-ion annealing efficiency,as well as the structure itself,which affects the process of He bubble evolution and formation.The grain boundaries also act as sinks to accumulate He bubbles.No obvious irradiation damage but slight intensity reduction and left shift of diffraction peaks were observed according to the grazing incidence x-ray diffraction and Raman spectra characterizations,indicating that defects of interstitials and vacancies were generated.     

Planar waveguides in neodymium-doped calcium niobium gallium garnet crystals produced by proton implantation

In this work, the fabrication and optical properties of a planar waveguide in a neodymium-doped calcium niobium gallium garnet(Nd:CNGG) crystal are reported. The waveguide is produced by proton(H~+) implantation at 480 ke V and a fluence of 1.0×10~(17) ions/cm~2. The prism-coupling measurement is performed to obtain the dark mode of the waveguide at a wavelength of 632.8nm. The reflectivity calculation method(RCM) is used to reconstruct the refractive index profile. The finite-difference beam propagation method(FD-BPM) is employed to calculate the guided mode profile of the waveguide.The stopping and range of ions in matter 2010(SRIM 2010) code is used to simulate the damage profile induced by the ion implantation. The experimental and theoretical results indicate that the waveguide can confine the light propagation.     

Same-sign tetralepton signature in type-Ⅱ seesaw at lepton colliders

The same-sign tetralepton signature via the mixing of neutral Higgs bosons and their cascade decays to charged Higgs bosons is a unique signal in the type-Ⅱ seesaw model with the mass spectrum M_A⁰≈M_H⁰>M_H⁺>M_H^±±.In this study,we investigate this signature at future lepton colliders,such as the ILC,CLIC,and MuC.Direct searches for doubly charged scalar H^±±at the LHC have excluded MHg+t<350(870) GeV in the H^±±+W^±W(±)(l^±±)decay mode.Therefore,we choose M_A⁰=400,600,1000,1500 GeV as our benchmark scenarios.Constrained by direct search,H^±±+W^±W(±)(l^±±)d=is the only viable decay mode for Mρ=400 GeV at the √s=1 TeV ILC.With an integrated luminosity L=8 ab^-1,the promising region,with approximately 150 signal events,corresponds to a narrow band in the range of 10^-4 GeV≤v△≤10^-2GeV.Meanwhile,for Mpo=600 GeV at the √s=1.5 TeV CLIC,approximately 10 signal events can be produced with L=2.5 ab^-1.For heavier triplet scalars M_A⁰■870 GeV,although the H^±± decay mode is allowed,the cascade decays are suppressed.A maximum event number~16 can be obtained at approximately v△~4×10⁴GeV and λ₁₄~0.26 for M_A⁰=1000 GeV with L=5 ab^-1 at the √s=3 TeV CLIC.Finally,we find that this signature is not promising for M_A⁰= 1500 GeV at the √s=6 TeV MuC.Based on the benchmark scenarios,we also study the observability of this signature.In the H^±±+W^±W(±)(l^±±)d mode,one can probe MρS 800(1160) GeV at future lepton colliders.     

Strong coupling between height of gaps and thickness of thermal boundary layer in partitioned convection system

A direct numerical simulation(DNS) method is used to calculate the partitioned convection system with Ra number ranging from 10~7 to 2×10~9.Using the boundary layer thickness to normalize the height of gaps d, we find a strong consistency between the variation of the TD number(the average value of the temperature in each heat transfer channel is averaged after taking the absolute values) with the change of the height of gaps and the variation of the TD number with the change of Ra number in partitioned convection.For a given thickness of partition, heights of gaps are approximately equal to 0.5 or 1 time of the thermal boundary layer thickness λ_θ at different Ra numbers.TD number representing temperature characteristics is almost the constant value, which means that TD number is a function of d/λ_θ only.Analysis of local temperature field of area in gaps shows that the temperature distribution in the gaps are basically the same when d/λ_θ is certain.The heat transfer Nu number of the system at d/λ_θ≈ 0.5 is larger than that of d/λ_θ≈ 1, both of them have the same scaling law with Ra number and N_u～Ra~(0.25).     

A super-high resolution frequency standard measuring approach based on phase coincidence characteristics between signals

A method for super high resolution comparison measurement is proposed in this paper with a comparison between the frequency standards of different nominal frequencies, which is based on phase coincidence detection of the two compared signals. It utilizes the regular phase shift characteristics between the signals. The resolution of the measurement approach can reach 10-13/s at 5 MHz, and the self-calibration resolution can achieve 10-14/s in the comparison between 10 MHz and 100 MHz, or even can reach 10-15/s in the comparison between 10 MHz and 190 MHz. This method implies significant progress in the development of the high precision frequency standard comparison technology.     

Efficient second harmonic generation between photonic and plasmonic modes in a tunable transparent conducting oxide waveguide

Efficient second harmonic generation(SHG) in a nonlinear transparent conducting oxide(TCO) stripe waveguide that incorporates an organic polymer is theoretically investigated. The phase match condition between the fundamental photonic mode at the second harmonic and the fundamental long-range plasmonic mode at the fundamental frequency can be satisfied by dynamically or statically tuning the free carrier concentration of the TCO. The theoretically generated signal reaches its maximum up to 56.4 m W at a propagation distance of 34.8 μm for a pumping power of 1 W. The corresponding normalized conversion efficiency of the phase-matched SHG is up to 4.65 × 10~3W~(-1)cm~(-2).     

Complete leaky mode coupling in dual-core photonic crystal fibre based on the coupled-mode theory

This paper theoretically investigates the dependence of leaky mode coupling between inner core fundamental mode and outer core defect mode on phase and loss matching in pure silica dual-core photonic crystal fibres with the multi-pole method. The complete mode coupling can take place when both the phase and loss matching conditions are satisfied at the avoided anti-crossing wavelength. It shows the influences of cladding structure parameters including the diameters of cladding air holes d₁, diameters of outer core holes d₂ and hole to hole pitch Λ on the characteristics of leaky modes coupling. The coupled-mode theory is used to analyse the mode transition characteristics and the complete coupling can be clearly indicated by comparing the real and imaginary parts of propagation constant of the leaky modes.