The Unified Equation of State for Dark Matter and Dark Energy

We assume that dark matter and dark energy satisfy the unified equation of state: $p=B(z)\rho$, with $p=p_{dE}$, $\rho=\rho_{dm}+\rho_{dE}$, where the pressure of dark matter $p_{dm}=0$ has been taken into account. A special function $B=-\frac{A}{(1+z)^{\alpha}}$ is presented, which can well describe the evolution of the universe. In this model, the universe will end up with a Big Rip. By further simple analysis, we know other choices of the function $B$ can also describe the universe but lead to a different doomsday.Comment: 7 pages, 3 figures, ws-mpla.cls, accepted by MPL

The Real Scalar Field in Schwarzschild-de Sitter Spacetime

In this paper, the real scalar field equation in Schwarzschild-de Sitter spacetime is solved numerically with high precision. A method called polynomial approximation is introduced to derive the relation between the tortoise coordinate x and the radius r. This method is different from the tangent approximation [1] and leads to more accurate result. The Nariai black hole is then discussed in details. We find that the wave function is harmonic only near the horizons as I. Brevik and B. Simonsen [1] found. Howerver the wave function is not harmonic in the region of the potential peak, with amplitude increasing instead. Furthermore, we also find that, when cosmological constant decreases, the potential peak increases, and the maximum wave amplitude increases.Comment: 11 pages, 5 figures. To be published in volume 35(2003), G.R.

Massless scalar field quasi-normal frequencies of Schwarzschild black hole in the quintessence background

We evaluate the massless scalar field quasi-normal frequencies of Schwarzschild black hole in the quintessence background, using the third-order WKB approximation method. Results show that quintessence decreases the oscillation frequency while increases the damping time of the scalar field. Moreover, with the increase of the quintessential state parameter ω q (the ratio of the pressure to the energy density), the imaginary parts’ absolute values of the quasi-normal frequencies increase monotonously. This indicates that the scalar field decays more rapidly in the larger ω q quintessence state, which agrees with the cases of other perturbation fields for black holes in the quintessence background. For the special case of SdS black hole (ω q =−1), the oscillation frequency and the damping rate increase with the decrease of the normalization factor c (corresponding to the cosmological constant Λ in SdS black hole)

Reconfiguration of college physics teaching based on the “Trinity” education model

College physics not only carries the task of learning basic knowledge for science and technology students, but also plays a deep role in educating students through thinking and politics. It has irreplaceable nurturing functions in cultivating students’ ideals and beliefs, cultivating national sentiments and strengthening scientific thinking. In the process of education and teaching, we insist on the “trinity” education mode of ideologies, mindset and knowledge, cultivating people with ideologies, reshaping people with thinking and enlightening people with knowledge. Thus, we maximize the effect of “teaching” and “learning”. A new form of university physics teaching is built by optimizing teaching resources and reforming the teaching mode, based on the characteristics of the curriculum and the students. Therefore, we realize the knowledge transfer to value leadership from teaching knowledge, and truly implement the fundamental task of moral education

Reconfiguration of college physics teaching based on the “Trinity” education model

College physics not only carries the task of learning basic knowledge for science and technology students, but also plays a deep role in educating students through thinking and politics. It has irreplaceable nurturing functions in cultivating students’ ideals and beliefs, cultivating national sentiments and strengthening scientific thinking. In the process of education and teaching, we insist on the “trinity” education mode of ideologies, mindset and knowledge, cultivating people with ideologies, reshaping people with thinking and enlightening people with knowledge. Thus, we maximize the effect of “teaching” and “learning”. A new form of university physics teaching is built by optimizing teaching resources and reforming the teaching mode, based on the characteristics of the curriculum and the students. Therefore, we realize the knowledge transfer to value leadership from teaching knowledge, and truly implement the fundamental task of moral education

The surface geometry and shadow of a Schwarzschild black hole with halo

We have studied the surface geometry and shadows of Schwarzschild black hole with a halo containing quadrupolar and octopolar terms. We found the event horizon is prolate for the quadrupole strength $\mathcal{Q}<0$, and it becomes oblate for $\mathcal{Q}>0$. The event horizon stretches downward for $\mathcal{O}>0$. But for the case of $\mathcal{O}<0$, the event horizon stretches upward. We found the radius of light rings $r_{LR}$ in the space-time of Schwarzschild black hole with halo only depends on the quadrupole strength $\mathcal{Q}$. The black hole shadow is oblate when the quadrupole strength $\mathcal{Q}$ is larger than zero, and it is prolate when $\mathcal{Q}$ is less than zero. Black hole shadow shifts upward when the octopolar strength $\mathcal{O}$ is less than zero, and shifts downward when $\mathcal{O}$ is larger than zero. From the observable width $W$, height $H$, oblateness $K$ and distortion parameter $\delta$ of black hole shadow, one can determine the quadrupole strength $\mathcal{Q}$ and the octopolar strength $\mathcal{O}$ of Schwarzschild black hole with halo. Black hole shadow is always a circle for the observers with the inclination angle $\theta_{obs}=0$, and becomes bigger with the increase of $\mathcal{Q}$ or $\mathcal{O}$. Our results show that the quadrupolar and octopolar terms yield a series of interesting patterns for the shadow of a Schwarzschild black hole with halo.Comment: 18 pages,11 figure

Steroidal glycoalkaloids in potato foods as affected by cooking methods

Potato and its products have become indispensable foods and snacks for most people. Steroidal glycoalkaloids (SGAs) occur in all tissues of the potato, and consuming potatoes with a high SGA content harms human health. Therefore, the effects of different cooking methods on the SGA content in potato foods were investigated in this study. The results indicated that adding food-grade acetic acid during the manufacturing process did not affect the SGA content in stir-fried shredded potatoes or fresh mashed potatoes. However, the SGA content in potato food after peeling was significantly lower than that in non-peeled food, and the volume ratio of potato skin to flesh decreased with the increase of the potato tuber volume. Therefore, potato breeders and farmers should make the most hard to increase the proportion of commodity potato via corresponding science and technology. In addition, frying significantly reduced the SGA content in potato chips. Further research indicated that SGAs degraded slowly at 150°C, while they degraded rapidly at 190°C within 30 min. The temperature of rapeseed oil in the frying process can be as high above 200°C. Thus, frying significantly decreased the SGA content in potato chips, which could be attributed to temperature. These results will provide a theoretical basis and practical guidance for potato breeding and cooking

Hyperprogressive disease during PD-1 blockade in patients with advanced pancreatic cancer

The occurrence of markedly accelerated tumor growth during immunotherapy is considered a new mode of progression called hyperprogressive disease (HPD) and its impact on pancreatic cancer (PC) patients receiving immunotherapy is unknown. In this study, we described and explored the incidence, prognosis and predictors of HPD in patients with advanced PC treated with programmed cell death-1 (PD-1) inhibitors. We retrospectively analyzed clinicopathological data from 104 patients with advanced pancreatic cancer who were treated with PD-1 inhibitors at our institution during 2015–2020 and identified 10 (9.6%) patients with HPD. Overall survival (OS) was significantly poorer in patients with HPD compared to patients with progressive disease (PD) (median OS: 5.6 vs. 3.6 months, p 2, liver metastasis, antibiotic therapy within 21 days before immunotherapy (Abx B21), hemoglobin (Hb) level 2. Subgroup analysis showed that high levels of CA19-9 at baseline were associated with the development of subsequent HPD (p = .024) and a worse prognosis (mOS:16.2 months vs. 6.1 months, p < .01). Our study demonstrated that HPD may occur in PC patients treated with PD-1 inhibitors and is associated with several clinicopathological characteristics and poor prognosis. The baseline tumor marker CA19-9 may be one of the early predictors of HPD development in PC patients receiving immunotherapy

Modified Sagnac imaging spectropolarimeter for full linear Stokes parameters

A modified Sagnac imaging spectropolarimeter is conceptually described. It consists of a spectral-polarimetric modulator, a modified Sagnac interferometer with large optical path difference, and a CCD camera. This design modulates the Stokes components of the input light into different wave numbers and obtains the modulated interferogram in snapshot mode, and the spectra of the Stokes components can be separated and demodulated from the interferogram. The performance of the system is demonstrated through a numerical simulation, and a novel method is proposed to detect the polarization parameters including the degree of polarization and polarization direction for eliminating the aliasing effects between linear Stokes parameters. Compared with the existing imaging spectrometers, the modified Sagnac imaging spectropolarimeter can acquire one-dimensional spatial information and its full linear spectropolarimetric information in one exposure, and some other spatial information can be obtained by push-broom mode