Metal-ion permeation in congested nanochannels: the exposure effect of Ag plus ions on the phosphorescent properties of a gold(I)-pyrazolate complex that is confined in the nanoscopic channels of mesoporous silica

An organometallic/silica nanocomposite of a 1D cylindrical assembly of a trinuclear gold(I)pyrazolate complex ([Au3Pz3]) that was confined inside the nanoscopic channels of hexagonal mesoporous silica ([Au3Pz3]/silicahex), emitted red light with a luminescence center at 693 nm upon photoexcitation at 276 nm owing to a AuI?AuI metallophilic interaction. When a film of [Au3Pz3]/silicahex was dipped into a solution of Ag+ in tetrahydrofuran (THF), the resulting nanocomposite material (Ag@[Au3Pz3]/silicahex) emitted green light with a new luminescence center at 486 nm, which was characteristic of a AuI?AgI heterometallic interaction. Changes in the emission/excitation and XPS spectra of Ag@[Au3Pz3]/silicahex revealed that Ag+ ions permeated into the congested nanochannels of [Au3Pz3]/silicahex, which were filled with the cylindrical assembly of [Au3Pz3]

有限要素法を用いた大規模空間吊り天井の脱落被害再現シミュレーション

Many ceiling collapse damages were observed in wide-area structures such as gymnasiums during the 2011 Great East-Japan Earthquake and the 2016 Kumamoto Earthquake. The prevention of ceiling collapse phenomena is an important issue not only to save people\u27s lives, but to keep these facilities to be safely used as shelters after earthquakes. In this paper, a numerical analysis to simulate the ceiling collapse in a full-scale gymnasium specimen, which was tested at the E-Defense shaking table facility in 2014, was conducted. A numerical model consisted of steel structural frames and suspended ceilings were constructed. All the members were modeled using linear Timoshenko beam elements and the adaptively shifted integration (ASI) - Gauss code was applied. Hangers and hanging bolts were modeled in one piece. The plaster boards were assumed as rigid in out of plane direction and only the mass of rock wool boards was considered. Their strength were neglected. Clips and screws were modeled with minute, small elements. Each plaster board was modeled separately to consider local contact between plaster boards, which was simulated by modeling the screws slightly apart. Elasto-plastic buckling of braces and hanging bolts were considered by modeling them with eight beam elements each and two hinge elements on both ends. The clips connecting ceiling joists and ceiling joist receivers are small and delicate components that may be detached during repeated excitation. Once there is a local detachment of clips, a change in the load distribution may cause a chain reaction of detachments, which ends in a drop of plaster boards. Furthermore, the detachments of hanging bolts that are connected to the structural members composing the roof, and failure of screws on plaster boards are assumed to be other main causes of the ceiling collapse. The results of some preliminary tests conducted to see the actual strength of these components are implemented in the analysis for criteria. The numerical result was validated by the experimental result, which was performed at the E-Defense under an input of two continuous K-NET Sendai 50% waves. The acceleration responses, the spectrum and the displacement responses obtained on the roof matched well with the experimental result. According to the results, the plaster boards near walls pattered down occasionally at the first peak of the first wave. These were due to detachment of clips and screws caused by collisions to the walls. Then, the clips near roof top began to get loose due to buckling of hanging bolts caused by vertical excitation, which ends, at the first peak of the second wave, in drop of plaster boards in a wide range. The numerical result had shown the collapse of the ceilings progressed owing to the detachment of clips that connected the ceiling joists to the ceiling joist receivers, which eventually led to a large-scale collapse of the ceilings

Intracavity femtosecond-pulse compression with the addition of highly nonlinear organic materials

It is experimentally shown that using organic materials of high nonlinear refractive index dissolved in a saturable-absorber solution permits femtosecond-pulse compression in a simple colliding-pulse mode-locked laser employing cavity-mirror dispersion adjustment

A chirp-compensation technique using incident-angle changes of cavity mirrors in a femtosecond pulse laser

A technique for chirp-compensation in a CPM laser is presented. By using the change of the incident angle to multilayer dielectric cavity mirrors, the intracavity second-order dispersion φ^[・・] (ω) is adjusted without any additional elements. It is confirmed that the optimum value of φ^[・・](ω) = +2.1 x 10^[-28] s2 obtained when up-chirp was compensated and pulses as short as 55 fs were generated is reasonable, by comparison to analytic results of chirp behaviors. In addition, the effect of the third-order dispersion φ^[・・・] (ω) at the optimum value of φ^[・・] (ω) on pulses is evaluated

Analysis of a synchronously mode-locked and internally frequency-doubled CW dye laser

We present analytical studies of a synchronously modelocked and internally frequency-doubled CW (SMLFD) dye laser. The analysis describes the cavity detuning behavior of the pulse duration and the square of its peak intensity (the signal intensity of the autocorrelation trace) in terms of system parameters for different lengths of the intracavity crystal. The results predict the broadening of the pulse duration with the increase of the crystal length even though the condition of the group velocity matching is satisfied. It is shown that the prediction is in good agreement with the experimental results of the SMLFD rhodamine 6G laser with an ADP crystal in the cavity. Furthermore, the variation of the minimum pulse duration at the optimum cavity length as a function of the harmonic conversion efficiency is derived

Femtosecond-pulse laser chirp compensated by cavity-mirror dispersion

The duration of pulses generated from a simple colliding-pulse mode-locked cw dye laser is measured as a function of cavity-mirror dispersion. The optimum amount of mirror dispersion of Φ(ω) ≅ + 1.8 x 10^[-28] sec2 and a suitable mirror coating for upchirp compensation are identified. The adjustment of mirror dispersion only, without additional dispersive elements, generates continuous trains of pulses as short as 50 fsec

A single-photon sensitive synchroscan streak camera for room temperature picosecond emission dynamics of adenine and polyadenylic acid

It is experimentally verified that a synchroscan streak camera, incorporating a microchannel plate and synchronizing with UV picosecond pulses generated inside the cavity of a mode-locked CW ring dye laser, has enough sensitivity to detect picosecond emission phenomena in the region of a single-photon event. To demonstrate the usefulness of the synchroscan streak camera, the first measurement of time- and wavelength-resolved emissions in the picosecond region is successfully carried out for adenine and polyadenylic acid aqueous solutions at room temperature, and shows that their shortest lifetimes, due to the monomer fluorescence, are 6 and 8 ps, respectively

A compact synchroscan streak camera using a microchannel plate incorporated tube

A compact synchroscan streak camera, which incorporates a microchannel plates providing a high light gain, has been constructed. The camera has been operated in synchronism with a synchronous-passive hybrid mode-locked CW dye laser, and the overall time resolution has been 10.8 and 25.9 ps for a recording of ～160 and ～ lO^[8] cycles of dye laser pulses, respectively. In addition, by using the camera system with the dye laser a weak fluorescence profile (a quantum yield of ～10^[-3]) of an important biomolecule has been directly observed on a picosecond time scale