Understanding first law of thermodynamics of black holes

We approach the thermodynamic properties of the d-dimensional RN black holes, discuss the three expressions for the first law of thermodynamics for black holes and calculate the energies in the three regions of the black hole spacetimes. Some remarks of the first law of thermodynamics and the thermal properties for the black holes are given.     

Fermions tunneling of higher-dimensional Kerr–Anti-de Sitter black hole with one rotational parameter

The 1/2 spin fermions tunneling at the horizon of n-dimensional Kerr–Anti-de Sitter black hole with one rotational parameter is researched via semi-classical approximation method, and the Hawking temperature and fermions tunneling rate are obtained in this Letter. Using a new method, the semi-classical Hamilton–Jacobi equation is gotten from the Dirac equation in this Letter, and the work makes several quantum tunneling theories more harmonious.     

Black hole entropy,log correction and inverse area correction

In this Letter, we first extend the Parikh–Wilczek tunneling framework to a general spherically symmetric black hole, and calculate the tunneling rate of the emission particles to the second order accuracy. Then, by assuming the emission process satisfies an underlying unitary theory, we correct the entropy of a general spherically symmetric black hole. We find that the log correction and the inverse area correction to the entropy is also suitable for a general spherically symmetric black hole.     

Dy3+/Tm3+共掺杂钒磷酸钇的共沉淀法合成及光谱性质

以Y2O3、Dy2O3、Tm2O3、V2O5、(NH4)2GPO4为原料,采用共沉淀化学法合成了体色纯白的Dy^3 、Tm^3 共掺杂YP1-xVxO4荧光粉。对合成荧光粉的V^5 ／p^5 、Dy^3 ／Tm^3 摩尔比等条件进行了研究。利用SEM、变温紫外激光激发下的发射光谱及紫外激发下的发射光谱,对所合成的粉体的表面形貌及发光性能进行了表征。YP1-xVxO4：Dy^3 ,Tm^3 荧光粉在325nm紫外激光激发下,低温时存在基质VO4^3-的蓝色宽带发射,随着温度升高,VO4^3 吸收的激发能量更有效地传递给Dy^3 、Tm^3 ,使其发光逐渐增强;在254nm的紫外光激发下,YP1-xVxO4：Dy^3 ,Tm^3 荧光粉发白光,是一种潜在的二基色高压汞灯用荧光粉。     

Comparative evaluation of Dy(III) selective poly(vinyl) chloride based membrane electrodes of macrocyclic tetraimine Schiff's bases

Three different derivatives of macrocyclic tetraimine Schiff's base have been synthesized and explored as a neutral ionophores for preparing poly(vinyl chloride) based membrane sensors selective to Dy³⁺. The addition of sodium tetraphenyl borate and various plasticizers, viz., o-NPOE, DBP, DBBP, DOP and CN has been found to substantially improve the performance of the sensors. The best performance was obtained with the sensor no. 1 having membrane of Schiff's base (SL-1) with composition (w/w) SL-1 (4.5%): PVC (30.5%): o-NPOE (59.5%): NaTPB (5.5%). This sensor exhibits Nernstian response with slope 19.4 mV/decade of activity in the concentration range of  10⁻⁸ to 1.0 × 10⁻² M Dy³⁺, performs satisfactorily over wide pH range of (2.8-7.2) with a fast response time (10 s). The sensor was also found to work satisfactorily in partially non-aqueous media up to 20% (v/v) content of acetonitrile, methanol or ethanol. The proposed sensor can be used over a period of 1.5 months without significant drift in potentials. The sensor has been also utilized for the determination of Dy³⁺ level in different soil samples.     

Shape Transition and Triaxial Interaction Effect in the Structure of 152-166Dy Isotopes

The positive parity states in even-even ^152-166Dy are studied systematically in the framework of the interacting boson model (IBM). A cubic term, L=3, has been added to the Hamiltonian in order to produce the effect of triaxiality on the energy spectrum. The potential energy surfaces as a function of β and γ deformation parameters, for all isotopes have been produced. Energy levels and reduced electric quadrupole transition probabilities are calculated in framework of IBM with Cubic term (IBMC). All results are compared with available experimental data. It is found that these isotopes can be described by a schematic Hamiltonian in transition from U(5) (vibration) to SU(3) (rotation) dynamic symmetry.     

A black hole with quantum core

A model black hole, holding a ‘quantum core’ characterized by the Planck order matter density, is revisited here. Based on the quantum improved Newton’s potential drawn out of the loop quantum cosmology we propose a Schwarzschild class, quantum improved black hole line-element that upholds the existence of Planck-dense quantum matter core. Causality is kept preserved in this proposal. Quite in a natural way the quantum core emerges closely homogeneous in its interior matter distribution. The radius of the quantum core turns out to be necessarily proportional to one-third power of the black hole mass. Hawking process of black hole evaporation leads to a shrinking quantum core, and as the mass of black hole approaches near about the Planck mass, the rate of evaporation diminishes rapidly and eventually leaves a cold remnant having a Planck order mass. Proposed model supports the standard quantum geometrical logarithmic correction to black hole entropy-area law.     

Dy~(3+),Sm~(3+)共掺杂Ca_2A1[AlSiO_7]荧光粉的发光性质研究

采用高温固相反应法合成了一系列Dy~(3+)、Sm~(3+)单掺杂和共掺杂铝方柱石发光材料,详细地研究了Dy~(3+)、Sm~(3+)掺杂对铝方柱石的结构和发光性质的影响。XRD结果表明Dy~(3+)、Sm~(3+)离子单掺杂和共掺杂样品均形成了单相的铝方柱石结构化合物,并没有改变基质的晶体结构。发光光谱表明,通过调节Dy~(3+)、Sm~(3+)离子的掺杂比例,发光颜色可实现从黄色到黄白色的可控调节。此外,发射和激发光谱表明,Dy~(3+)与Sm~(3+)离子之间存在有效的光谱重叠,暗示着Dy~(3+)→Sm~(3+)的能量传递。荧光寿命衰减结果进一步证实Dy~(3+)与Sm~(3+)离子之间是一种无辐射共振能量传递方式。     

SrBPO_5:Dy~(3+)荧光粉的制备及光谱性能研究

通过高温固相法制备了用于紫外激发的系列SrBPO_5:Dy~(3+)荧光粉,并对样品进行了XRD分析和发光性能测试。结果表明,合成样品为单一相的SrBPO_5材料;在388 nm紫外光激发下,样品的发射光谱包括485和575 nm两个发射峰。研究了Dy~(3+)浓度,Mg~(2+)加入量,烧结温度以及电荷补偿剂对发射光谱的影响。当Dy~(3+)掺杂摩尔浓度为4 mol%时发光强度最强;随着Mg~(2+)的加入量的增加B/Y峰的强度比不断增加;最佳烧结温度为1 100℃;Na~+作为电荷补偿剂效果最佳。该荧光粉有较强的黄色发射峰,可以增强UV激发的白光LED的黄光成分从而提高其穿透雾霾的能力。