Subjects: Physics >> Nuclear Physics submitted time 2023-12-28
Yuemei Peng
Jianshe Cao
Jinhui Chen
Haiyi Dong
Ping He
Yi Jiao
Ling Kang
WenKang
Jian Li
Jingyi Li
Guoping Lin
Fang Liu
Fengli Long
Cai Meng
Xin Qi
Huamin Qu
Yanfeng Sui
Sheng Wang
Gang Xu
Qiang Ye
Abstract： The high-energy photon source (HEPS) is the first fourth-generation synchrotron light source facility in China. The HEPS injector consists of a linear accelerator (Linac) and a full energy booster. The booster captures the electron beam from the Linac and increases its energy to the value required for the storage ring. The full-energy beam could be injected to the storage ring directly or after “high-energy accumulation.” On November 17, 2023, the key booster parameters successfully reached their corresponding target values. These milestone results were achieved based on numerous contributions, including nearly a decade of physical design, years of equipment development and installation, and months of beam commissioning. As measured at the extraction energy of 6 GeV, the averaged beam current and emittance reached 8.57 mA with 5 bunches and 30.37 nm.rad with a single-bunch charge of 5.58 nC, compared with the corresponding target values of 6.6 mA and 35 nm.rad, respectively. This paper presents the physical design, equipment development, installation, and commissioning process of the HEPS booster.
Subjects: Astronomy >> Astrophysical processes submitted time 2023-02-19
Abstract： The spatial distribution between dark matter and baryonic matter of the Universe is biased or deviates from each other. In this work, by comparing the results derived from IllustrisTNG and WIGEON simulations, we find that many results obtained from TNG are similar to those from WIGEON data, but differences between the two simulations do exist. For the ratio of density power spectrum between dark matter and baryonic matter, as scales become smaller and smaller, the power spectra for baryons are increasingly suppressed for WIGEON simulations; while for TNG simulations, the suppression stops at $k=15-20h{\rm Mpc}^{-1}$, and the power spectrum ratios increase when $k>20h{\rm Mpc}^{-1}$. The suppression of power ratio for WIGEON is also redshift-dependent. From $z=1$ to $z=0$, the power ratio decreases from about 70% to less than 50% at $k=8h{\rm Mpc}^{-1}$. For TNG simulation, the suppression of power ratio is enhanced with decreasing redshifts in the scale range $k>4h{\rm Mpc}^{-1}$, but is nearly unchanged with redshifts in $k<4h{\rm Mpc}^{-1}$ These results indicate that turbulent heating can also have the consequence to suppress the power ratio between baryons and dark matter. Regarding the power suppression for TNG simulations as the norm, the power suppression by turbulence for WIGEON simulations is roughly estimated to be 45% at $k=2h{\rm Mpc}^{-1}$, and gradually increases to 69% at $k=8h{\rm Mpc}^{-1}$, indicating the impact of turbulence on the cosmic baryons are more significant on small scales.
Peer Review Status:
Awaiting Review
Subjects: Astronomy >> Astrophysical processes submitted time 2023-02-19
Abstract： It is a common practice to evaluate probability density function or matter spatial density function from statistical samples. Kernel density estimation is a frequently used method, but to select an optimal bandwidth of kernel estimation, which is completely based on data samples, is a long-term issue that has not been well settled so far. There exist analytic formulae of optimal kernel bandwidth, but they cannot be applied directly to data samples, since they depend on the unknown underlying density functions from which the samples are drawn. In this work, we devise an approach to pick out the totally data-based optimal bandwidth. First, we derive correction formulae for the analytic formulae of optimal bandwidth to compute the roughness of the sample's density function. Then substitute the correction formulae into the analytic formulae for optimal bandwidth, and through iteration, we obtain the sample's optimal bandwidth. Compared with analytic formulae, our approach gives very good results, with relative differences from the analytic formulae being only 2%-3% for a sample size larger than 10^4. This approach can also be generalized easily to cases of variable kernel estimations.
Peer Review Status:Awaiting Review
Subjects: Astronomy >> Astrophysical processes submitted time 2023-02-19
Abstract： The wavelet analysis technique is a powerful tool and is widely used in broad disciplines of engineering, technology, and sciences. In this work, we present a novel scheme of constructing continuous wavelet functions, in which the wavelet functions are obtained by taking the first derivative of smoothing functions with respect to the scale parameter. Due to this wavelet constructing scheme, the inverse transforms are only one-dimensional integrations with respect to the scale parameter, and hence the continuous wavelet transforms constructed in this way are more ready to use than the usual scheme. We then apply the Gaussian-derived wavelet constructed by our scheme to computations of the density power spectrum for dark matter, the velocity power spectrum and the kinetic energy spectrum for baryonic fluid. These computations exhibit the convenience and strength of the continuous wavelet transforms. The transforms are very easy to perform, and we believe that the simplicity of our wavelet scheme will make continuous wavelet transforms very useful in practice.
Peer Review Status:Awaiting Review
Subjects: Astronomy >> Astrophysical processes submitted time 2023-02-19
Abstract： In this work, we propose new statistical tools that are capable of characterizing the simultaneous dependence of dark matter and gas clustering on the scale and the density environment, and these are the environment-dependent wavelet power spectrum (env-WPS), the environment-dependent bias function (env-bias), and the environment-dependent wavelet cross-correlation function (env-WCC). These statistics are applied to the dark matter and baryonic gas density fields of the \texttt{TNG100-1} simulation at redshifts of $z=3.0$-$0.0$, and to \texttt{Illustris-1} and \texttt{SIMBA} at $z=0$. The measurements of the env-WPSs suggest that the clustering strengths of both the dark matter and the gas increase with increasing density, while that of a Gaussian field shows no density dependence. By measuring the env-bias and env-WCC, we find that they vary significantly with the environment, scale, and redshift. A noteworthy feature is that at $z=0.0$, the gas is less biased in denser environments of $\Delta \gtrsim 10$ around $3 \ h\mathrm{Mpc}^{-1}$, due to the gas reaccretion caused by the decreased AGN feedback strength at lower redshifts. We also find that the gas correlates more tightly with the dark matter in both the most dense and underdense environments than in other environments at all epochs. Even at $z=0$, the env-WCC is greater than $0.9$ in $\Delta \gtrsim 200$ and $\Delta \lesssim 0.1$ at scales of $k \lesssim 10 h\mathrm{Mpc}^{-1}$. In summary, our results support the local density environment having a non-negligible impact on the deviations between dark matter and gas distributions up to large scales.
Peer Review Status:Awaiting Review
Subjects: Astronomy >> Astrophysical processes submitted time 2023-02-19
Abstract： The continuous wavelet transform (CWT) is very useful for processing signals with intricate and irregular structures in astrophysics and cosmology. It is crucial to propose precise and fast algorithms for the CWT. In this work, we review and compare four different fast CWT algorithms for the 1D signals, including the FFTCWT, the V97CWT, the M02CWT, and the A19CWT. The FFTCWT algorithm implements the CWT using the Fast Fourier Transform (FFT) with a computational complexity of $\mathcal{O}(N\log_2N)$ per scale. The rest algorithms achieve the complexity of $\mathcal{O}(N)$ per scale by simplifying the CWT into some smaller convolutions. We illustrate explicitly how to set the parameters as well as the boundary conditions for them. To examine the actual performance of these algorithms, we use them to perform the CWT of signals with different wavelets. From the aspect of accuracy, we find that the FFTCWT is the most accurate algorithm, though its accuracy degrades a lot when processing the non-periodic signal with zero boundaries. The accuracy of $\mathcal{O}(N)$ algorithms is robust to signals with different boundaries, and the M02CWT is more accurate than the V97CWT and A19CWT. From the aspect of speed, the $\mathcal{O}(N)$ algorithms do not show an overall speed superiority over the FFTCWT at sampling numbers of $N\lesssim10^6$, which is due to their large leading constants. Only the speed of the V97CWT with real wavelets is comparable to that of the FFTCWT. However, both the FFTCWT and V97CWT are substantially less efficient in processing the non-periodic signal because of zero padding. Finally, we conduct wavelet analysis of the 1D density fields, which demonstrate the convenience and power of techniques based on the CWT. We publicly release our CWT codes as resources for the community.
Peer Review Status:Awaiting Review
Subjects: Astronomy >> Astrophysical processes submitted time 2023-02-19
Abstract： Continuous wavelet analysis has been increasingly employed in various fields of science and engineering due to its remarkable ability to maintain optimal resolution in both space and scale. Here, we introduce wavelet-based statistics, including the wavelet power spectrum, wavelet cross-correlation and wavelet bicoherence, to analyze the large-scale clustering of matter. For this purpose, we perform wavelet transforms on the density distribution obtained from the one-dimensional Zel'dovich approximation and then measure the wavelet power spectra and wavelet bicoherences of this density distribution. Our results suggest that the wavelet power spectrum and wavelet bicoherence can identify the effects of local environments on the clustering at different scales. Moreover, we apply the statistics based on the three-dimensional isotropic wavelet to the IllustrisTNG simulation at z = 0, and investigate the environmental dependence of the matter clustering. We find that the clustering strength of the total matter increases with increasing local density except on the largest scales. Besides, we notice that the gas traces the dark matter better than stars on large scales in all environments. On small scales, the cross-correlation between the dark matter and gas first decreases and then increases with increasing density. This is related to the impacts of the AGN feedback on the matter distribution, which also varies with the density environment in a similar trend to the cross-correlation between the dark matter and gas. Our findings are qualitatively consistent with previous studies about the matter clustering.
Peer Review Status:Awaiting Review
Subjects: Astronomy >> Astrophysical processes submitted time 2023-02-19
Abstract： The continuous wavelet transform (CWT) is very useful for processing signals with intricate and irregular structures in astrophysics and cosmology. It is crucial to propose precise and fast algorithms for the CWT. In this work, we review and compare four different fast CWT algorithms for the 1D signals, including the FFTCWT, the V97CWT, the M02CWT, and the A19CWT. The FFTCWT algorithm implements the CWT using the Fast Fourier Transform (FFT) with a computational complexity of $\mathcal{O}(N\log_2N)$ per scale. The rest algorithms achieve the complexity of $\mathcal{O}(N)$ per scale by simplifying the CWT into some smaller convolutions. We illustrate explicitly how to set the parameters as well as the boundary conditions for them. To examine the actual performance of these algorithms, we use them to perform the CWT of signals with different wavelets. From the aspect of accuracy, we find that the FFTCWT is the most accurate algorithm, though its accuracy degrades a lot when processing the non-periodic signal with zero boundaries. The accuracy of $\mathcal{O}(N)$ algorithms is robust to signals with different boundaries, and the M02CWT is more accurate than the V97CWT and A19CWT. From the aspect of speed, the $\mathcal{O}(N)$ algorithms do not show an overall speed superiority over the FFTCWT at sampling numbers of $N\lesssim10^6$, which is due to their large leading constants. Only the speed of the V97CWT with real wavelets is comparable to that of the FFTCWT. However, both the FFTCWT and V97CWT are substantially less efficient in processing the non-periodic signal because of zero padding. Finally, we conduct wavelet analysis of the 1D density fields, which demonstrate the convenience and power of techniques based on the CWT. We publicly release our CWT codes as resources for the community.
Peer Review Status:Awaiting Review
Subjects: Biology >> Botany >> Plant cytology, plant genetics & plant morphology submitted time 2016-05-03
Yan Zou
Satya Chintamanani
Ping He
Hirotada Fukushige
Liping Yu
Meiyu Shao
Lihuang Zhu
David F. Hildebrand
Xiaoyan Tang
Jian-Min Zhou
Abstract： Jasmonates (JAs) are rapidly induced after wounding and act as key regulators for wound induced signaling pathway. However, what perceives the wound signal and how that triggers JA biosynthesis remains poorly understood. To identify components involved in Arabidopsis wound and JA signaling pathway, we screened for mutants with abnormal expression of a luciferase reporter, which is under the control of a wound-responsive promoter of an ethylene response factor (ERF) transcription factor gene, RAP2.6 (Related to APetala 2.6). The rea1 (R
Peer Review Status:Awaiting Review
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