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111.
通过对合成金刚石的原材料和合成产物——石墨、Ni70Mn25Co5触媒、普通人造金刚石、黑色人造金刚石、NiMnCoC熔体的磁化率测试,以及对黑色人造金刚石和普通人造金刚石破碎断面扫描电镜的对比分析,认为黑色人造金刚石形成低磁性的原因是由于合成过程中温度偏高、压力偏低,生长的金刚石质量差、裂纹多。晶体内夹杂了很多石墨与触媒包裹体,同时金刚石表面与金刚石晶体内的触媒包裹体之间形成贯穿性的裂纹。在金刚石化学提纯处理过程中,金刚石晶体内的铁磁性触媒包裹体杂质被通过裂纹进入的酸除去。因而在检测金刚石磁性时,黑色金刚石的磁性很小,呈弱磁性。 相似文献
112.
利用Vaidya-Bonner-de S itter黑洞视界面附近的熵密度,导出黑洞的瞬时辐出度,得到了任一时刻黑洞的瞬时辐出度总是正比于黑洞视界温度四次方的结论。导出的广义Stefan-Boltzm ann系数不再是一个恒量,而是一个与黑洞视界的变化率、黑洞视界面附近的时空度规及黑洞的吸收与辐射系数有关的一个动比例系数,揭示了黑洞周围的引力场与其热辐射之间存在着必然的内在联系。 相似文献
113.
光助Fenton试剂氧化降解染料直接耐晒黑G的研究 总被引:2,自引:1,他引:1
文章研究了影响Fenton试剂氧化降解持久性有机污染物直接耐晒黑G的因素,如光源的选择、初始pH值、H2O2的用量、Fe2+的用量、阳离子交换树脂载体的引入等,通过研究确定了各因素的优化条件。研究结果表明:太阳光照能有效的促进直接耐晒黑G染料的降解脱色,大大缩短反应时间;引入阳离子交换树脂后,可增强Fenton氧化反应的活性,降解效果更好。 相似文献
114.
《Wave Motion》2020
Shock testing is an important issue for the survivability of an equipment under shock environment in aerospace and military industries. One of the problems faced in conventional shock testing devices is the need for redesigning of the geometry whenever the responses to different shock environments are tested. To circumvent the redesigning processes, a structure with two ‘acoustic black holes (ABHs)’ on both ends, referred to as the beam with dual ABHs, is proposed as a shock testing device. The beam with dual ABHs is capable of simulating diverse shock environments by controlling the applied force because it can be regarded as an infinite beam at high frequency range with the aid of the anechoic terminations by the ABHs. To systematically investigate the beam with dual ABHs, we develop a wave-based method that uses the reflection matrix of an ABH to perform free and forced vibration analyses. From the analyses on frequency response function and shock response spectrum of the beam with dual ABH, it is suggested that the beam with dual ABHs is feasible as a semi-permanent shock testing device. 相似文献
115.
The fundamental equation of the thermodynamic system gives the relation between the internal energy, entropy and volume of two adjacent equilibrium states. Taking a higher-dimensional charged Gauss–Bonnet black hole in de Sitter space as a thermodynamic system, the state parameters have to meet the fundamental equation of thermodynamics. We introduce the effective thermodynamic quantities to describe the black hole in de Sitter space. Considering that in the lukewarm case the temperature of the black hole horizon is equal to that of the cosmological horizon, we conjecture that the effective temperature has the same value. In this way, we can obtain the entropy formula of spacetime by solving the differential equation. We find that the total entropy contains an extra term besides the sum of the entropies of the two horizons. The corrected term of the entropy is a function of the ratio of the black hole horizon radius to the cosmological horizon radius, and is independent of the charge of the spacetime. 相似文献
116.
Seyed Hossein Hendi Fereshteh Azari Ebrahim Rahimi Mina Elahi Zahra Owjifard Zahra Armanfard 《Annalen der Physik》2020,532(10):2000162
It is known that scalar-tensor gravity models can be studied in Einstein and Jordan frames. In this paper, a model of scalar-tensor gravity in Einstein's frame is considered to calculate the Lifshitz-like black hole solutions with different horizon topologies. Thermodynamic properties and first order van der Waals-like phase transition are studied, and it is found that the Lifshitz parameter affects the phase structure. In addition, thermal stability is investigated by using the behavior of heat capacity and various methods of geometrical thermodynamics. 相似文献
117.
Xin Xu Yifan Jiang Min Wang Huimeng Wang Chunhua Lu Huanghao Yang 《Particle & Particle Systems Characterization》2020,37(12):2000243
Black phosphorus nanosheet (BPNS) is a promising multifunctional material in the biomedical field with biodegradability and low side effects, however its features are always weakened severely owing to its poor stability. Here, a novel method is developed for improving the defect of BPNS based on the effective protection of poly(lactic-co-glycolic acid) (PLGA), which preserves the stable photothermal therapy (PTT) effect of BPNS and biodegradability of the material. Meanwhile, doxorubicin (DOX) is loaded on BPNS/PLGA to get BPNS/PLGA/DOX for further chemotherapy and preventing the recurrence of tumor after PTT. The presented combined therapeutic strategy exploits the strengths and improves the defects of BPNS, thus developing an efficient and safe nanoagent for cancer therapy, which affords and reveals the great potential of BPNS in nanomedicine. 相似文献
118.
通过第一性原理对平面内双轴应力作用下的单层黑磷能带结构进行了计算.双轴拉伸应力作用下单层黑磷始终保持直接带隙性质,双轴压缩应力作用下的单层黑磷则发生了直接带隙转变为间接带隙的现象,当双轴压缩应力增加到7%时单层黑磷带隙闭合. 相似文献
119.
文章首先将史瓦西黑洞场中自由下落质点的固有时(诺维科夫坐标时)公式,由自然单位制化成了国际单位制中的形式.然后,根据牛顿第二定律和万有引力定律,推导出了自由下落质点经历的绝对时间公式,进而证明了广义相对论中自由落体经历的固有时,恰好等于牛顿力学给出的绝对时间.最后,对自由下落质点在黑洞内外经历的时间进行了特例计算. 相似文献
120.
Accurate correction of arbitrary spin fermion quantum tunneling from non-stationary Kerr-de Sitter black hole based on corrected Lorentz dispersion relation 下载免费PDF全文
Bei Sha Zhi-E Liu Yu-Zhen Liu Xia Tan Jie Zhang Shu-Zheng Yang 《中国物理C(英文版)》2020,44(12):125104-125104-8
According to a corrected dispersion relation proposed in the study on the string theory and quantum gravity theory, the Rarita-Schwinger equation was precisely modified, which resulted in the Rarita-Schwinger-Hamilton-Jacobi equation. Using this equation, the characteristics of arbitrary spin fermion quantum tunneling radiation from non-stationary Kerr-de Sitter black holes were determined. A number of accurately corrected physical quantities, such as surface gravity, chemical potential, tunneling probability, and Hawking temperature, which describe the properties of black holes, were derived. This research has enriched the research methods and enabled increased precision in black hole physics research. 相似文献