基于GIS的给水管网阀门管理系统的设计与开发

基于对城市给水管网设备管理实际需求的调查,以地理信息系统为技术支持,在宏扬给水管网地理信息系统软件(HY-waterGIS)平台上,对管网设备管理系统的设计开发做了深入研究,并以阀门管理为例,说明给水管网设备管理系统的建立过程.     

Growth of LiF/LiBaF<Subscript>3</Subscript> eutectic scintillator crystals and their optical properties

Li-containing materials can be applied as neutron scintillators, and LiBaF₃ can discriminate neutron and gamma rays. Moreover, LIF/LiBaF₃ can have higher cross section of thermal-neutron capture compared with LiBaF₃. In this study, LiF (82.5 mol%) and (Ba_1?x RE _x )F₂ (17.5 mol%, RE = Ce and Eu, x = 0.002) eutectic crystals, LiF/RE:LiBaF₃, were grown by the micropulling down method with different pulling rates (growth rate) in order to observe the eutectic structure. Lamellar microstructure was formed for each pulling rate. LiF/Ce:LiBaF₃ excited by 5.5-MeV alpha rays had a broad peak at ~350 nm corresponding to 5d–4f transition of Ce³⁺. On the other hand, LiF/Eu:LiBaF₃ had two scintillation processes; a sharp emission was originated from ⁶P_7/2 → ⁸S_7/2 transitions in the 4f electronic configuration of Eu²⁺ at 360 nm, and a broad one was attributed to Eu²⁺ trapped exciton recombination at 400–450 nm. Since scintillation light was observed for these materials, these scintillators are sensitive to neutrons.     

Cobalt-Nanoporous Carbon Functionalized Nanocomposite-Based Triboelectric Nanogenerator for Contactless and Sustainable Self-Powered Sensor Systems

Triboelectric nanogenerators (TENGs), which operate in contactless mode and avoid physical contact, are highly attractive for self-powered sensor systems aiming to achieve long-term reliable operation and reduce rubbing friction. Herein, an ultra-flexible and high-performance contactless double-layer TENG (CDL-TENG) is first designed and fabricated using a metal–organic framework-based cobalt nanoporous carbon (Co-NPC)/Ecoflex with MXene/Ecoflex nanocomposite layer for self-powered sensor applications. The porous structure of the Co-NPC provides a high-surface-area of the nanocomposite and the charge storage layer of the MXene/Ecoflex nanocomposite accumulates more negative charge to improve the functionality of the CDL-TENG two and three times, respectively. Compared with Ecoflex film-based TENGs, the fabricated CDL-TENG exhibits an eight-fold slower decay rate owing to charge trapping characteristics, which were confirmed by surface potential measurements. The CDL-TENG shows excellent humidity and acceleration sensitivity of about 0.3 V/% and 2.06 Vs² m⁻¹. The CDL-TENG also offers non-contact position detection performance in the 20 cm range. Furthermore, the CDL-TENG is successfully integrated with mobile-vehicles and an intelligent robot to perform obstacle and human-motion detection. Finally, a contactless door-lock password authentication system was demonstrated. These multifunctional benefits make it useful for numerous applications, including artificial intelligence, human-machine interfaces, and self-powered sensors.     

Synthesis of metal oxide composite nanosheets and their pressure sensing properties

This study presents the synthesis of metal oxides composite nanosheets(oxides of cobalt, zinc and iron) and their pressure sensing properties. A transducer has been fabricated to directly measure the resistance–pressure and impedance–pressure relationships of pristine nanopowder. At the initial stage, a nanopowder sample of 10 mm diameter and 1 mm height was placed in the transducer and by applying pressure of up to 8.15 kN/m2;the DC resistance and the impedance are reduced by 44% on average. It can be explained by the densification of the samples and a decrease in porosity due to the effect of pressure. It was also observed that the DC resistance increases with time and saturated within 8 min. It is considered that this phenomenon is based on the effect of displacement currents of bound charges. The dependences of the impedance phase(θ) on frequency and pressure have also been investigated.     

Design of new oxide crystals with improved structural stability

We introduce a method of searching for crystals with high structural stability and its application to the garnet, KTiOPO₄ (KTP), huntite-borate, and langasite structures. Results are presented which show that, by using appropriate substitution, an increase of the stability can be achieved. This review gives models and experimental techniques of optimization of compositions for the complex oxide materials with the given structure. Sometimes application of the method mentioned can be used for the determination of the congruently melting composition. Optimization of composition from the point of view of minimization of atom-atom interaction potential energy is discussed. Experimental methods reported are based on the study of segregation and phase formation phenomena.     

Scintillation properties of Nd, Tm, and Er doped LuF3 scintillators in the vacuum ultra violet region

In order to develop novel vacuum ultra violet (VUV) emitting scintillators, we grew Nd 0.5%, Tm 0.5%, and Er 0.5% doped LuF₃ scintillators by the μ-pulling down method, because LuF₃ has a very wide band gap and Nd³⁺, Tm³⁺, and Er³⁺ luminescence centers show fast and intense 5d-4f emission in VUV region. Transmittance and X-ray induced radioluminescence were studied in these three samples using our original spectrometer made by Bunkou-Keiki company. In the VUV region, transmittance of 20-60% was achieved for all the samples. The emission peaks appeared at approximately 180, 165, and 164 nm for Nd³⁺, Tm³⁺, and Er³⁺ doped LuF₃, respectively. Using PMT R8778 (Hamamatsu), we measured their light yields under ²⁴¹Am α-ray excitation. Compared with Nd:LaF₃ scintillator, which has 33 photoelectrons/5.5 MeV α, Nd:LuF₃ and Tm:LuF₃ showed 900±90 and 170±20 ph/5.5 MeV-α, respectively. Only for the Nd doped one, we can detect ¹³⁷Cs 662 keV γ-ray photoabsorption peak and the light yield of 1200±120 ph/MeV was measured. We also investigated their decay time profiles by picosecond pulse X-ray equipped streak camera, and the main decay component of Nd:LuF₃ turned out to be 7.63 ns.     

Crystal growth and scintillation properties of Nd:CaF2

Nd³⁺ doped CaF₂ single crystal scintillator has been investigated. We tried to grow 1%, 5%, 10%, 20%, 30% and 40% Nd³⁺ doped CaF₂ single crystals by the simple melt-solidifying method. Powder X-ray diffraction (XRD) patterns were measured to identify the phase of all the samples. The XRD patterns of all the samples were similar to CaF₂. Those samples are compared in terms of their X-ray-excited radioluminescence spectra, transmittance, α-ray-excited decay time and light yield. When the X-ray is used for excitation, luminescence is observed in the VUV region. Transmittance of the crystals is more than 70% at wavelengths longer than about 180 nm. In the decay kinetics, the fast components of the samples are distributed in less than 25 ns time range and the slow components of sample are distributed in more than 90 ns. These decay times became shorter with increasing Nd³⁺ concentration. They are related to the Nd³⁺ 5d-4f VUV emission. The light yields of samples are distributed in 5-2500 photon/5.5 MeV α-ray and decrease with increasing Nd³⁺ concentration.     

Correlation between crystal grain sizes of transparent ceramics and scintillation light yields

Light yields of Y₂O₃ ceramics are different from specimen to specimen. Nature of this phenomenon is not clear yet. Furthermore, origin of emission peaks for Y₂O₃ is not well understood. The results reported suggest that the emission derived from trapped excitons originates from the defects accumulated in the grain boundaries of the ceramics. In this paper, average grain size is introduced in order to evaluate defects inside the ceramics. Relationship between average crystal grain size and scintillation light yield is demonstrated.     

Crystal growth of oxide and fluoride materials for optical, piezoelectric and other applications

High quality oxide and fluoride single crystals for optical, piezoelectric and other applications have been grown by advanced crystal growth techniques. La₃Nb_0.5Ga_5.5O₁₄ and La₃Ta_0.5Ga_5.5O₁₄ piezoelectric single crystals of size and quality comparable to La₃Ga₅SiO₁₄ (langasite), have been produced. The piezoelectric and device properties of the crystals were investigated. A search for new langasite-type materials was also performed. Growth conditions of (La,Sr)(Al,Ta)O₃ and Ca₈La₂(PO₄)₆O₂ single crystals are discussed. These crystals have excellent lattice matching with GaN, a promising material for optoelectronic devices. Promising optical micro-crystals—K₃Li₂Nb₅O₁₅, KNbO₃ and Y₃Al₅O₁₂—and new structural materials, Al₂O₃Y₃Al₅O₁₂ eutectic fibers, have been grown by the micro-pulling-down (-PD) technique. The advantages of the -PD technique have been shown. Ce-doped fluoride single crystals—LiCaAlF₆, LiYF₄ and BaLiF₃—have been grown for solid state UV laser applications. Growth results and optical characterizations are discussed.     

Humidity sensing properties of CU_2O-PEPC nanocomposite films

正A blend of copper oxide nanopowder(Cu_2O),3 wt.%,and poly-N-epoxypropylcarbazole(PEPC), 2 wt.%,in benzol was drop-casted on glass substrates with pre-deposited surface-type silver electrodes for the fabrication of Cu_2O-PEPC nanocomposite thin films.The thicknesses of the Cu_2O-PEPC films were in the range of 10-13μm.The effect of humidity on the electrical properties of the nanocomposite films was investigated by measuring the capacitance and dissipation of the samples at two different frequencies of the applied voltage:120 Hz and 1 kHz.The AC resistance of the samples was determined from the dissipation values,and the DC resistance was measured directly.The effect of ageing on the humidity sensing properties of the nanocomposite was observed. After ageing,it was observed that at 120 Hz and 1 kHz,under a humidity of up to 86%RH,the capacitance of the cell increased by 85 and 8 times,and the resistance decreased by 345 and 157 times,accordingly,with respect to 30%RH conditions.It was found that with an increase in frequency,the capacitance and resistance of the samples decreased.It is assumed that the humidity response of the cell is associated with the diffusion of water vapors and doping of the semiconductor nanocomposite by water molecules.