Deep Imaging of the HCG 95 Field.I.Ultra-diffuse Galaxies

We present a detection of 89 candidates of ultra-diffuse galaxies (UDGs) in a 4.9 degree$^2$ field centered on the Hickson Compact Group 95 (HCG 95) using deep $g$- and $r$-band images taken with the Chinese Near Object Survey Telescope. This field contains one rich galaxy cluster (Abell 2588 at $z$=0.199) and two poor clusters (Pegasus I at $z$=0.013 and Pegasus II at $z$=0.040). The 89 candidates are likely associated with the two poor clusters, giving about 50 $-$ 60 true UDGs with a half-light radius $r_{\rm e} > 1.5$ kpc and a central surface brightness $\mu(g,0) > 24.0$ mag arcsec$^{-2}$. Deep $z$'-band images are available for 84 of the 89 galaxies from the Dark Energy Camera Legacy Survey (DECaLS), confirming that these galaxies have an extremely low central surface brightness. Moreover, our UDG candidates are spread over a wide range in $g-r$ color, and $\sim$26% are as blue as normal star-forming galaxies, which is suggestive of young UDGs that are still in formation. Interestingly, we find that one UDG linked with HCG 95 is a gas-rich galaxy with H I mass $1.1 \times 10^{9} M_{\odot}$ detected by the Very Large Array, and has a stellar mass of $M_\star \sim 1.8 \times 10^{8}$ $M_{\odot}$. This indicates that UDGs at least partially overlap with the population of nearly dark galaxies found in deep H I surveys. Our results show that the high abundance of blue UDGs in the HCG 95 field is favored by the environment of poor galaxy clusters residing in H I-rich large-scale structures.Comment: Published in Ap

Analysis of road network pattern considering population distribution and central business district.

This paper proposes a road network growing model with the consideration of population distribution and central business district (CBD) attraction. In the model, the relative neighborhood graph (RNG) is introduced as the connection mechanism to capture the haracteristics of road network topology. The simulation experiment is set up to illustrate the effects of population distribution and CBD attraction on the characteristics of road network. Moreover, several topological attributes of road network is evaluated by using coverage, circuitness, treeness and total length in the experiment. Finally, the suggested model is verified in the simulation of China and Beijing Highway networks

Dynamic Network Design Problem under Demand Uncertainty: An Adjustable Robust Optimization Approach

This paper develops an adjustable robust optimization approach for a network design problem explicitly incorporating traffic dynamics and demand uncertainty. In particular, a cell transmission model based network design problem of linear programming type is considered to describe dynamic traffic flows, and a polyhedral uncertainty set is used to characterize the demand uncertainty. The major contribution of this paper is to formulate such an adjustable robust network design problem as a tractable linear programming model and justify the model which is less conservative by comparing its solution performance with the robust solution from the usual robust model. The numerical results using one network from the literature demonstrate the modeling advantage of the adjustable robust optimization and provided strategic managerial insights for enacting capacity expansion policies under demand uncertainty

New challenges in mitigating climate change: Digital teaching for the sustainable development and innovation

The phenomenon of climate change has become a global challenge that affects human activities in many ways. Exploring the sustainability and innovativeness of digital education is an important reference for the further implementation of science and education strategies and positive effects on climate change mitigation. This study designed two questionnaires for basic and tertiary education to address variability in education and collected 523 samples for basic education and 412 samples for tertiary education respectively. Using digital teaching practices and digital teaching quality as mediators, structural equation modelling (SEM) was used to examine the impact of digital education on sustainability and innovation in education. Research shows that digital teaching and learning in basic and higher education can significantly contribute to the two-way development of educational sustainability and innovation, through digital teaching and learning practices. Digital teaching practice and digital teaching quality in higher education play a complete mediating role, while basic education only plays a partial mediating role. Higher education emphasizes digital teaching and learning practice processes and teaching quality, and most students hope that online teaching and learning can be further integrated with offline education to form a new model of education. This study will help government departments understand the pedagogical reality of digital education at a deeper level and provide ideas for the subsequent sustainable development and educational innovation of digital teaching. It can also provide new ideas for climate change mitigation and sustainable development

Notations.

<p>Notations.</p

Effects of Different Mixed Ratio of Maize Straw and Cabbage Wastes on Silage Quality

Ensiling, a wet preservation method, is an appropriate method of storing feedstock for biogas production. Fresh maize straw, contain enough water-soluble carbohydrates, is the prevailing material producing biogas, but research on preservation and storage of maize straw as feedstock for anaerobic digestion is still in its infancy. Generally in China, the free sugars are consumed, the water evaporates during wilting and field drying, giving rise to fail to achieve the demand of good-quality silage. In view of strong complementary in terms of physical structure, nutrient/moisture content of maize straw and vegetables, this paper propose a hypothesis of trans-seasonal mixed ensiling for biogas production. The objective of the current work was to evaluate effects of different mixed ratio of maize straw (MS) and cabbage wastes (CW) on silage quality, taking into account the silage quality, chemical composition and structural properties of feedstock. Mixed ensiling of maize straw and cabbage waste were prepared in 1.6-L plastic silos at 25 degrees C. The mixed mass ratios (MMR) of MS and CW were 19:29, 21:27, 23:25, 25:23, 27:21 and 29:19, respectively. The results show that the content of cellulose and hemicellulose after ensiling were increased, achieving the goal of seasonal storage for MS. When the MMR was 27:21, that is, the moist content was 73% (MEMS73), the pH value had a minimum and the content of lactic acid was highest after mixed ensiling for 30 days. Therefore, the optimum MMR of MS and CW was 21:27 for storage of maize straw. The microtoporaghy of SEM indicated that the cracks and ruleless pores were taken on the surfaces of maize straw silage, compared to the compact lignocellulosic matrix before ensiling. The crystalline degree of cellulose was decreased after ensiling. In a word, ensiling is an appropriate feasibly storage method to preserve MS and should be considered a promising method for stable storage of biogas feedstock

Road network topology of China (Beijing and Shanghai as its CBDs).

<p>Road network topology of China (Beijing and Shanghai as its CBDs).</p

The uitility of population distribution.

<p>The uitility of population distribution.</p