A study of luminescence properties in the boron-doped lead tungstate

The present work is focused on the enhancement of luminescence in PbWO₄ by boron (B) ions doping. A series of boron-doped PbWO₄ polycrystals were synthesized by solid-state reaction in air atmosphere. The crystal structure of PbWO₄ was decided from powder X-ray diffraction data. The X-ray excited luminescence, UV excitation and emission spectra measurements were conducted on these samples under the same conditions to evaluate the doping effects of luminescence on PbWO₄. The B-doped PbWO₄ gave an enhanced broad emission band centered between 420 and 520 nm depending on different doping concentration. Another scintillating crystal, Bi₄Ge₃O₁₂, was also introduced to compare the effects of luminescence with B-doped PbWO₄. The doping mechanism of B ions in the PbWO₄ lattices was briefly discussed according to the present experimental results.     

Preparation of magnetic poly(methylmethacrylate–divinylbenzene–glycidylmethacrylate) microspheres by spraying suspension polymerization and their use for protein adsorption

Moderately uniform magnetic poly(methylmethacrylate–divinylbenzene–glycidylmethacrylate) microspheres (poly(MMA–DVB–GMA) microspheres) were prepared by spraying suspension copolymerization of methyl methacrylate, divinylbenzene and glycidyl methacrylate in the presence of Fe₃O₄ magnetic fluid. A protein adsorption assay indicated that these magnetic microspheres could significantly improve the capacity of protein adsorption.     

p-adic Transcendence and p-adic Transcendence Measures for the Values of Mahler Type Functions

We prove the p-adic transcendence and p-adic transcendence measures for the values of some Mahler type functions.     

Mixed-potential-type zirconia-based NOx sensor using Rh-loaded NiO sensing electrode operating at high temperatures

The improvement in sensing characteristics of mixed-potential-type NO₂ sensor based on an yttria-stabilized zirconia (YSZ) plate was examined by an addition of noble metal to NiO sensing-electrode. Among the various noble metals (Pt, Rh, Ir, Pd and Ru) examined, Rh was found to give a significant enhancement in NO₂ sensitivity. In addition, this enhancement was maximum when the Rh content in NiO-SE was 3 wt.%. The sensitivity (emf) to 50 ppm NO₂ was as high as about 77 mV for the sensor using the 3 wt.% Rh-loaded NiO-SE at 800 °C under the wet condition (5 vol.% H₂O). The NO₂ sensitivity was hardly affected by the change of H₂O and CO₂ concentration in the examined range of 5–15 and 5–20 vol.%, respectively, and was almost stable for about 50 days tested at 800 °C. It was speculated that the improved kinetic effect of Rh loading on the cathodic reaction of NO₂ at the interface of SE/YSZ was the major contributing factor for the enhanced NO₂ sensitivity of the sensor.     

A facile way for preparing tin nanoparticles from bulk tin via ultrasound dispersion

In this paper, we reported a facile and rapid process to prepare tin nanoparticles from bulk tin via ultrasound dispersion. The morphology and structure of synthesized tin nanoparticles were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectrum (XPS) and thermogravimetric analysis (TGA). The results show that the morphology of tin nanoparticles is spherical and the structure of tin nanoparticles has the same crystal structure as the bulk tin. In addition, the tribological property of tin nanoparticles as additives in oil is evaluated on a four-ball tester and the results show that tin nanoparticles exhibit good performance in wear.     

Existence of Solutions for a Quasilinear Schrödinger Equation with Potential Vanishing

Acta Mathematicae Applicatae Sinica, English Series - We study the following quasilinear Schrödinger equation $$ - \Delta u + V(x)u - \Delta ({u^2})u = K(x)g(u),\,\,\,\,\,\,\,\,x \in...     

Extension Operators Preserving Biholomorphic Mappings on Hartogs Domains*

In this paper, the authors extend the Roper-Suffridge operator on the generalized Hartogs domains. They mainly research the properties of the extended operator.By the characteristics of Hartogs domains and the geometric properties of subclasses of spirallike mappings, they obtain the extended Roper-Suffridge operator preserving almost starlikeness of complex order λ, almost spirallikeness of type β and order α, parabolic spirallikeness of type β and order ρ on the Hartogs domains in different co...     

Hα∞到Hβ∞复合算子的线性组合

设B是N维复空间C^N中的开单位球,φ_i为B上的解析自映射,H_α^∞表示定义在单位球上的加权解析函数空间.本文主要研究的是从空间H_α^∞到H_β^∞上的复合算子线性组合■的紧致性,其中λ_i(i=1,2,…,M)是非零常数.另外,根据紧致性等价条件,得出算子差分对(C_φ1-C_φ2)-(C_φ3-C_φ1)是紧致的当且仅当C_φ1-C_φ2与C_φ3-C_φ1都是紧致的算子.     

呼吸声分类技术研究及检测系统设计*

患有呼吸问题的病人由于呼吸道腺体不受意识控制、异物或者其本身肺部病变等原因会出现呼吸异常。医护人员通过病人的呼吸状况可以找寻和分析病人出现这种呼吸状况的原因。而以往呼吸声的诊断方式是专业的医护人员通过使用听诊器对病人进行肺部听诊。但是听诊的结果取决于医护人员的经验与相关参数。在初级诊断治疗阶段,初级医生识别听诊声的效率以及准确率很低,一般从20%到80%不等。因此会存在10%到20%的高误诊率（漏诊、错诊和延误）。本文提出了一种利用PVDF薄膜传感器提取语声特征的检测系统,该检测系统根据病人发出声音的不同,提取呼吸声特征值判断病人的呼吸状况。通过PVDF传感器采集的微弱呼吸声再经过KNN算法分类之后其识别率可达90.6%,对于细分种较类多的湿罗声,其识别率在80.2%左右。综上表明相比于传统听诊方式通过PVDF传感器采集识别的结果具有更高的准确性和可靠性,其判断呼吸状况的结果可以为医护人员提供参考,更好的为患有呼吸疾病的病人提供监测。     

Characterization of the low-temperature oxidation chemistry of an unsaturated aldehyde 2-butenal in a Jet-stirred reactor

Unsaturated aldehydes such as butenal are essential intermediates in the combustion of various alkenes and oxygenated biofuels. 2-Butenal is a typical intermediate included in the core mechanism, containing a C=C double bond adjacent to an aldehyde group. In the present work, the oxidation of 2-butenal is studied in a jet-stirred reactor (JSR) at atmospheric pressure under temperature ranging from 500 to 850 K. The synchrotron vacuum ultraviolet photoionization mass spectrometry is employed to identify the key intermediates. A kinetic model for 2-butenal oxidation is developed and validated against the experimental datasets. Fuel flux and sensitivity analyses are performed to clarify reactions governing the reactivity of 2-butenal. OH addition to the C=C double bond is essential for fuel reactivity at the initial stage. A combination of experimental observations and kinetic simulations is used to illuminate the Waddington mechanism initiated by OH addition. The resonance-stabilized feature of fuel radicals facilitates their interactions with HO₂ radicals, which replenishes a large amount of OH radicals and contributes to the formation of CO₂.