A
bstract
The search for long-lived particles (LLP) is an exciting physics opportunity in the upcoming runs of the Large Hadron Collider. In this paper, we focus on a new search strategy of using the ...High Granularity Calorimeter (HGCAL), part of the upgrade of the CMS detector, in such searches. In particular, we demonstrate that the high granularity of the calorimeter allows us to see “shower tracks” in the calorimeter, and can play a crucial role in identifying the signal and suppressing the background. We study the potential reach of the HGCAL using a signal model in which the Standard Model Higgs boson decays into a pair of LLPs,
h → XX
. After carefully estimating the Standard Model QCD and the misreconstructed fake-track backgrounds, we give the projected reach for both an existing vector boson fusion trigger and a novel displaced-track-based trigger. Our results show that the best reach for the Higgs decay branching ratio, BR(
h → XX
), in the vector boson fusion channel is about
O
(10
−
4
) with lifetime
cτ
X
∼ 0
.
1–1 meters, while for the gluon gluon fusion channel it is about
O
(10
−
5
–10
−
6
) for similar lifetimes. For longer lifetime
cτ
X
∼ 10
3
meters, our search could probe BR(
h → XX
) down to a few
×
10
−
4
(10
−
2
) in the gluon gluon fusion (vector boson fusion) channels, respectively. In comparison with these previous searches, our new search shows enhanced sensitivity in complementary regions of the LLP parameter space. We also comment on many improvements can be implemented to further improve our proposed search.
In this letter, concatenation of parity-check and polar codes is proposed to improve error correction performance. In addition, a heuristic construction of the parity-check-concatenated (PCC) polar ...codes is proposed. Simulation results show that the PCC polar codes with the heuristic construction have evident performance gains over the cyclic redundancy check-concatenated polar codes.
On-surface synthesis has been one of the hottest research fields in surface science in the last decade, owing to its great potential for bottom-up synthesis of functional molecules and covalent ...nanomaterials. Compared to classical in-solution chemistry, all of the on-surface reactions are done without solvent, thus very minimal byproducts and no limitation of solubility are involved. However, because of its typically required ultra-high vacuum conditions, where only limited catalysts can be used, a key challenge for on-surface synthesis is the precise control of the reaction pathway. Countless efforts have been made for controllable synthesis of target chemical structures on surfaces by distinct strategies. These strategies can be summarized under following aspects: 1) rational choice of surfaces; 2) template effects based on two-dimensional (2D) environments; 3) on-surface thermodynamic and kinetic controls; 4) the participation of chemisorbed nonmetal adatoms on surfaces. This report reviews the recent progress toward the control of on-surface synthesis and raises a series of questions at the end, which deserve further explorations in the future.
Display omitted
Efficient and accurate computer has become an indispensable tool in experimental research and teaching, and the computerized experimental methods of psychology have gradually diversified and ...standardized. This paper first introduces the application of computer-based experiment generation tools in psychology, and then describes the characteristics of computer-based experiments in psychology, such as single machine experiments, online experiments with a variety of devices. Finally, the paper introduces the generation system of psychological computerized experiment based on windows, and looks forward to the future of psychological computerized experiment in form, technology and application.
Recent advances in the fabrication of complex particles and particle‐based materials assisted by droplet‐based microfluidics are reviewed. Monodisperse particles with expected internal structures, ...morphologies, and sizes in the range of nanometers to hundreds of micrometers have received a good deal of attention in recent years. Due to the capability of generating monodisperse emulsions and of executing precise control and operations on the suspended droplets inside the microchannels, droplet‐based microfluidic devices have become powerful tools for fabricating complex particles with desired properties. Emulsions and multiple‐emulsions generated in the microfluidic devices can be composed of a variety of materials including aqueous solutions, gels, polymers and solutions containing functional nanoparticles. They are ideal microreactors or fine templates for synthesizing advanced particles, such as polymer particles, microcapsules, nanocrystals, and photonic crystal clusters or beads by further chemical or physical operations. These particles are promising materials that may be applicable for many fields, such as photonic materials, drug delivery systems, and bio‐analysis. From simple to complex, from spherical to nonspherical, from polymerization and reaction crystallization to self‐assembly, this review aims to help readers be aware of the many aspects of this field.
Droplet‐based microfluidic devices are powerful tools to generate emulsions and multiple‐emusions, which are fine templates for fabricating advanced particles and particle‐based materials. For instance, by further chemical or physical operations, multiple‐emulsions can be used to synthesize microcapsules that can be applied for drug delivery systems. By evaporating the solvent, photonic crystals can be fabricated through the self‐assembly of the colloidal particles suspended in the emulsion droplets.
AZ31B Mg/5052 Al laminated composite sheet with superior mechanical property and good sheet shape was fabricated by novel corrugated roll/flat roll corrugating rolling and flat roll/flat roll flat ...rolling (CFR) at elevated temperatures. The microstructural evolution and mechanical behavior variation of the composite sheet under CFR hot rolling condition were investigated by experimental and numerical simulation methods. The results show that first-pass corrugated rolling induces relatively high and inhomogeneous shear strain in the Mg side and various corrugated interface positions at a low reduction of 35%. It leads to significant grain refinement, outstanding basal texture modification as well as tensile twin activation Mg alloy, which perfectly coordinates the plastic deformation between hard-to-deform Mg and ductile Al and achieve the strong interface metallurgy bonding in Mg/Al sheet and also significantly improves the mechanical properties of Mg/Al composite sheet. The annealing before second-pass flat rolling causes the pronounced static recrystallization and grain growth of Mg alloy in corrugated-rolling Mg/Al sheet, and the formation of ~25 μm thick interfacial compound layer consisted of Mg17Al12 and Al3Mg2 two sublayers. Second-pass flat rolling with a reduction of 30% further imposes severe inhomogeneous shear deformation on the composite sheet, which results in the formation of a wave-shape three-dimensional bonding interface, and the interface compound layers cracking at peak and waist interface positions or fragmenting into well-aligned discrete particles to the bonding interface, in addition to substantial matrix microstructure refinement, texture modification and twin activation in Mg alloy. Such interface structure greatly enhances the interface bonding force of the Mg/Al composite sheet by the larger interface contact area, mechanical gearing effect as well as particle pinning effect. Hence the significant microstructural refinement, strong interface bonding and low residual stress induced by CFR process account for the excellent performance of the Mg/Al laminated composite sheet.
In this paper, we utilize deep learning methods to perform automatic feature learning from multi-source heterogeneous data, mapping different data into the same hidden space, and obtaining the deep ...features of the data associated with students and sports. A small amount of information is filtered from a large amount of input information by assigning weights in the attention mechanism and higher weights are assigned to it, and a collaborative filtering recommendation algorithm based on deep learning and algorithm evaluation index is proposed. The deep learning algorithm is integrated into the classroom of “basketball one-handed in situ over-the-shoulder shooting” in college B for empirical analysis, and the teaching effect is compared with that of the traditional teaching mode. The results show that the average scores of 50 meters, sit-ups, pull-ups, 800 meters, 1,000 meters, seated forward bending, and cross-direction running of the students in the physical education classroom based on deep learning are higher than those of the students in the traditional physical education classroom by 5.94, 6.83, 7.69, 6.56, 5.87, 5.1, and 3.68 in the physical fitness comparison analysis. Study shows that physical education teaching based on deep learning can improve students’ various physical qualities, which is of great significance and value in accelerating the high-quality development of physical education and promoting students’ comprehensive development.
In China’s marine industry, which has been growing quickly over the past few years, marine ecological compensation has been a critical framework for safeguarding the marine environment. Through the ...text analysis of the China’s marine ecological compensation legal system, this study found that there are multiple defects in it, including institutional supply shortage leads to lack of coordination and dispersion in China’s marine ecological compensation legislative system, the absence of legislative concept of ‘land-sea overall planning’ in China’s marine ecological compensation legal system, limited scope of China’s marine ecological compensation, lack of clear standards for marine ecological compensation, the relationship between marine planning and the marine ecological compensation system is not straightforward, and insufficiency of regulation on the marine ecological compensation. The paper suggests that priority should be given to developing a multi-level legal system for compensating marine ecological damage, the legal method of achieving ‘land-sea overall planning’ and a compensation mechanism that combines a variety of compensation methods with a scientific and reasonable standard should be established within China’s ecological compensation legal system, marine ecological compensation should be incorporated into marine planning and the separation of powers and implementation of the marine ecological compensation regulation should be enhanced.
At present, high-solids anaerobic digestion of sewage sludge has drawn great attention due to the superiority of its small land area footprint and low energy consumption. However, a high organic ...loading rate may cause acids accumulation and ammonia inhibition, thus leading to an inhibited pseudo-steady state in which electron transfer through interspecies hydrogen transfer (IHT) between acetogens and methanogens is blocked. In this study, adding 50 mg/g TS (total solid) magnetite clearly reduced the accumulation of short-chain fatty acids and accelerated methane production by 26.6%. As demonstrated, the individual processes of anaerobic digestion could not be improved by magnetite when methanogenesis was interrupted. Analyzing stable carbon isotopes and investigating the methanogenesis pathways using acetate and H2/CO2 as substrates together proved that direct interspecies electron transfer (DIET) was enhanced by magnetite. Metatranscriptomic analysis and determination of key enzymes showed that IHT could be partially substituted by enhanced DIET, and acetate-dependent methanogenesis was improved after the blockage of electron transfer was scavenged. Additionally, the expression of both pili and c-type cytochromes was found to decrease, indicating that magnetite could replace their roles for efficient electron transfer between acetogens and methanogens; thus, a robust chain of electron transfer was established.
High concentrations of ozone in urban and industrial regions worldwide have long been a major air quality issue. With the rapid increase in fossil fuel consumption in China over the past three ...decades, the emission of chemical precursors to ozone—nitrogen oxides and volatile organic compounds—has increased sharply, surpassing that of North America and Europe and raising concerns about worsening ozone pollution in China. Historically, research and control have prioritized acid rain, particulate matter, and more recently fine particulate matter (PM2.5). In contrast, less is known about ozone pollution, partly due to a lack of monitoring of atmospheric ozone and its precursors until recently. This review summarizes the main findings from published papers on the characteristics and sources and processes of ozone and ozone precursors in the boundary layer of urban and rural areas of China, including concentration levels, seasonal variation, meteorology conducive to photochemistry and pollution transport, key production and loss processes, ozone dependence on nitrogen oxides and volatile organic compounds, and the effects of ozone on crops and human health. Ozone concentrations exceeding the ambient air quality standard by 100–200% have been observed in China's major urban centers such as Jing-Jin-Ji, the Yangtze River delta, and the Pearl River delta, and limited studies suggest harmful effect of ozone on human health and agricultural corps; key chemical precursors and meteorological conditions conductive to ozone pollution have been investigated, and inter-city/region transport of ozone is significant. Several recommendations are given for future research and policy development on ground-level ozone.
Display omitted
•Studies of atmospheric ozone in urban and rural areas of China are reviewed.•Topics include abundance, chemical and meteorological processes, and effects.•Available data reveals serious and worsening ozone pollution in major areas of China.•Data from national network are needed to get a full picture of ozone pollution and to evaluate its impact.•Strategies for control ozone precursors need to be developed.
PDF
