用新Tortoise坐标变换计算变加速直线运动带电黑洞的熵

目的 计算变加速直线运动带电黑洞的熵.方法 在一种新的Tortoise坐标变换下,采用薄膜模型,讨论变加速直线运动带电黑洞的熵.结果 不但保证了熵与面积成正比的结论 ,而且得到了和静态一样简单的截断因子.结论 新Tortoise坐标变换比旧Tortoise坐标变换更具有优越性.     

新Tortoise坐标变换在讨论任意加速带电动态黑洞热性质中的和谐性

采用一种新的Tortoise坐标变换，在讨论任意加速带电动态黑洞的热性质时，不但保证了熵与面积成正比的结论，而且得到了和静态一样简单的截断因子。这种坐标变换在讨论黑洞的 Hawking辐射、熵及非热辐射时，表现出了前后的一致性与和谐性。     

利用广义不确定关系计算G—H—S黑洞的熵

目的 解决黑洞熵的发散问题.方法 利用广义不确定关系计算量子态数目,进而计算G-H-S黑洞的熵.结果 此方法不必引入截断因子,就避免了熵的发散问题,而且得到了黑洞熵与其视界面积成正比的结果.结论 利用广义不确定关系计算黑洞的熵,不必引入截断因子,就可避免熵的发散问题.     

De Sitter时空中的黑洞熵

目的 计算研究de Sitter时空中黑洞熵和视界面积间的关系.方法 利用在砖墙模型基础上发展起来的膜模型分别计算了Schwarzschild黑洞、动态的Vaidya和带电Vaidya黑洞熵.结果 在de Sitter时空中这些稳态和动态黑洞的熵均和视界面积成正比. 结论 再一次说明了膜结构的合理性.     

由黑洞的熵计算其温度

通过黑洞热力学第一定律,由黑洞的熵来计算黑洞的温度．由此方法算出的史瓦西黑洞和克尔-纽曼黑洞的温度与以前的结果相符,Vaidya黑洞的温度与引入新的乌龟坐标变换后算得的结果一致．     

Barriola-Vilenkin黑洞的统计熵

利用量子统计方法,直接计算Barriola-Vilenkin黑洞背景下玻色场和费米场的配分函数, 然后利用砖墙膜模型计算和讨论黑洞背景下玻色场和费米场的熵.     

利用广义不确定关系计算Vaidya-Bonner-deSitter黑洞的熵

利用广义不确定关系计算量子态数目,进而计算Vaidya-Bonner-de Sitter黑洞的熵。此方法与brick-wall模型相比,优点为不必引入截断因子,从而避免了发散问题。     

利用广义不确定关系计算Vaidya-Bonner黑洞的熵

利用广义不确定关系计算量子态数目，进而计算Vaidya-Bonner黑洞的熵,此方法与brick-wall模型相比，优点为不必引入截断因子，就避免了发散问题。     

一般球对称带电蒸发黑洞的非热辐射

研究一般球对称带电蒸发黑洞视界附近粒子的能级交错，给出交错能级最大值的表达式，得出一般球对称带电蒸发黑洞非热辐射频率范围是随时间变化的结论．     

在积系统中对Bowen拓扑熵的讨论

在讨论系统与积系统之间分离集和张成集关系的基础上,进一步研究了系统与积系统之间Bowen拓扑熵的一个关系.得到了积系统的Bowen拓扑熵不大于每个系统Bowen拓扑熵的和,同时积系统的Bowen拓扑熵不小于所有系统Bowen拓扑熵的平均值.由此进一步得到m次幂系统的Bowen拓扑熵等于系统Bowen拓扑熵的m倍.     

Fiber-optical analog of the event horizon

The physics at the event horizon resembles the behavior of waves in moving media. Horizons are formed where the local speed of the medium exceeds the wave velocity. We used ultrashort pulses in microstructured optical fibers to demonstrate the formation of an artificial event horizon in optics. We observed a classical optical effect: the blue-shifting of light at a white-hole horizon. We also showed by theoretical calculations that such a system is capable of probing the quantum effects of horizons, in particular Hawking radiation.     

Black hole accretion

Black holes are most often detected by the radiation produced when they gravitationally pull in surrounding gas, in a process called accretion. The efficiency with which the hot gas radiates its thermal energy strongly influences the geometry and dynamics of the accretion flow. Both radiatively efficient thin disks and radiatively inefficient thick disks are observed. When the accreting gas gets close to the central black hole, the radiation it produces becomes sensitive to the spin of the hole and the presence of an event horizon. Analysis of the luminosities and spectra of accreting black holes has yielded tantalizing evidence for both rotating holes and event horizons. Numerical simulations imply that the relativistic jets often seen from accreting black holes may be powered in part by the spin of the hole.     

Blood out of a stone

Almost 50 years ago, astronomers provided evidence for powerful radio emissions localized in two giant "lobes" on opposite sides of elliptical galaxies. These lobes are now known to be powered by jets emanating from black holes at the centers of the galaxies. In his Perspective, Blandford discusses how the black hole may generate the jets. He highlights the report by Koide et al., who have simulated one mechanism for supplying the jets with energy via a magnetic connection to the gas just outside the black hole's event horizon.     

关中地区塿土诊断层的形成过程及意义探讨

 【目的】通过对关中地区塿土剖面的多角度剖析,试图阐明此类土壤诊断层的形成过程及意义。【方法】根据野外考察和室内试验资料,对土壤剖面从诊断层划分、微形态特征、剖面构造空间变异、成土年龄等方面进行了综合分析和对比。【结果】Bt层形成于8 500～3 100 aB.P.,BC层在3 100～2 000 aB.P.,Ap层在2 000～0 aB.P.;BC层在理化性质、结构构造、微形态等方面与马兰黄土十分相似,而与Ap层和Bt层有显著的差异,Ap层与马兰黄土的相似性系数R1在0.8105～0.8951,Bt层的R1为0.6718,而BC层的R1在0.9051～0.9352。【结论】塿土具有Ap1-Ap2-Bc-Bt-Bk-C剖面构造,复合剖面的形成主要是由于环境变化引起成土强度发生变化的结果;Ap层是2 000 a以来人类施加土粪、农业耕作和粉尘堆积同时作用的综合产物,其特征主要受到人类活动强度和方式的控制,Bc层是3 100～2 000 aB.P.期间风尘自然堆积的产物,成土强度较弱;Bt是全新世大暖期的自然产物。     

Detection of the intrinsic size of Sagittarius A* through closure amplitude imaging

We have detected the intrinsic size of Sagittarius A*, the Galactic center radio source associated with a supermassive black hole, showing that the short-wavelength radio emission arises from very near the event horizon of the black hole. Radio observations with the Very Long Baseline Array show that the source has a size of 24 +/- 2 Schwarzschild radii at 7-millimeter wavelength. In one of eight 7-millimeter epochs, we also detected an increase in the intrinsic size of 60(-17)(+25)%. These observations place a lower limit to the mass density of Sagittarius A* of 1.4 x 10(4) solar masses per cubic astronomical unit.     

Phosphorus of Genetic Horizons of the Forest Sod-Podzolic Soil of the Pre-Urals

Characteristics of the phosphate regime of forest sod-podzolic soil is presented. It is shown that the organic phosphorus content sharply decreases down the profile starting from the podzolic horizon. The maximum content of mineral phosphates determined by the method of Sanders and Williams was found in forest litter and in the transitional eluvial horizon (A₂B) and amounted to 860 and 720 mg/kg. Iron phosphates prevail in the composition of mineral phosphates and, depending on the depth of the horizon, they are 48.8–63.2% of the sum of fractions. The shares of mobile and available to plants alkali metal phosphates and various basic phosphates are 2.9–10.1 and 10.0–14.9%, respectively.     

西天目山自然保护区森林土壤的地球化学特征

本文从土壤地球化学角度探讨西天目山自然保护区森林土壤的发育演化。在南坡自上至下挖掘土壤剖面8个,分层采样,带回室内作理化分析。结果表明,粘粒明显在心土层淀积,SiO_2、Fe_2O_3与K_2O均有在表土层相对积聚的迹象。心土层的粘粒硅铝率较表土层小。自高海拔至低海拔均有SiO_2的淋失,且淋失量比较接近,亦在不同气候条件下脱硅程度的一致。     

一种地震层位自动识别新算法

地震体数据中的信号断裂或减弱影响层位自动提取的准确性。由于层位在地震图像上表现出很强的方向性,通过分水岭算法和方向滤波方法增强三维地震层位的连续性,利用中心扩散方法进行全三维空间搜索并结合基于地震道的振幅匹配方法对搜索结果进行调整。通过试验分析,表明该算法可以适应信号较好的层位自动识别,提高层位解释效率。