scholarly journals Research Progress and Development Trends of Acoustic Metamaterials

Molecules ◽  
2021 ◽  
Vol 26 (13) ◽  
pp. 4018
Author(s):  
Hao Song ◽  
Xiaodong Ding ◽  
Zixian Cui ◽  
Haohao Hu
Keyword(s):  
Doppler Effect ◽  
Negative Refraction ◽  
Development Trend ◽  
Atomic Clusters ◽  
Research Progress ◽  
Acoustic Metamaterials ◽  
Development Trends ◽  
Related Research ◽  
The Past ◽  
Anomalous Doppler Effect

Acoustic metamaterials are materials with artificially designed structures, which have characteristics that surpass the behavior of natural materials, such as negative refraction, anomalous Doppler effect, plane focusing, etc. This article mainly introduces and summarizes the related research progress of acoustic metamaterials in the past two decades, focusing on meta-atomic acoustic metamaterials, metamolecular acoustic metamaterials, meta-atomic clusters and metamolecule cluster acoustic metamaterials. Finally, the research overview and development trend of acoustic metasurfaces are briefly introduced.

scholarly journals Research Progress of Locally Resonance Acoustic Metamaterials

2021 ◽  
Vol 248 ◽  
pp. 01041
Author(s):  
Du Zhehua
Keyword(s):  
Sound Wave ◽  
Negative Refraction ◽  
Low Frequency ◽  
Research Progress ◽  
Frequency Noise ◽  
Bragg Scattering ◽  
Acoustic Metamaterials ◽  
Low Frequency Noise ◽  
Phonon Crystal ◽  
Developed Surface

Bragg scattering phonon crystal and locally resonant acoustic metamaterials were introduced. In order to generate noise reduction, the lattice constant of Bragg scattering phonon crystal should be of the same order of magnitude as the wave length of the sound wave, therefore, its application field is limited. Locally resonant acoustic metamaterials consume sound energy by coupling its own resonant frequencies with those of sound waves at close range. Its size is two orders of magnitude smaller than the wavelength of sound wave; thus, the control of low-frequency noise by small-size acoustic metamaterials is realized. Locally resonant acoustic metamaterials have some extraordinary physical characteristic in the conventional medium for their special acoustic structural units, such as negative refraction and negative mass density. Especially in low frequency band, they have acoustic forbidden band in which the sound wave transmission is prohibited. Acoustic structural unit having resonant characteristics has been developed. Surface-mounted resonant element plate structures and thin film acoustic metamaterials are the normal types of locally resonant acoustic metamaterials. Their research and development provide a new method for low-frequency noise control.

LEGAL RESEARCH AT AHMAD IBRAHIM KULLIYYAH OF LAWS, INTERNATIONAL ISLAMIC UNIVERSITY MALAYSIA: TRENDS AND POLICIES

2012 ◽  
Vol 18 (1) ◽  
Author(s):  
Hunud Abia Kadouf ◽  
Umar Aimhanosi Oseini ◽  
Ainul Jaria Maidin
Keyword(s):  
Research Output ◽  
Academic Staff ◽  
Research Quality ◽  
Research Progress ◽  
Institutions Of Higher Education ◽  
Legal Research ◽  
The Past ◽  
Research Institution ◽  
Research Activities ◽  
The Status

The primary function of Ahmad Ibrahim Kulliyyah (Faculty) of Laws, at the very beginning of its inception, was that of teaching civil law and Sharî’ah subjects. As it matured, its vision has been varied from teaching to that of research with the aim of attaining the status of a full research institution that provides both quality research and best legal education in the region. Similar to other institutions of higher education in Malaysia, the responsibility of research is a shared function of both graduate students and the academic staff. The research output, on the part of the students is mostly composed of either Master Dissertations or PhD Theses. The academic members of the Faculty, however, are involved either in direct research, individually or jointly, supervision, and publications of their findings. By investigating and analyzing factors influencing research activities at AIKOL in the past twenty years, the researchers will be able to identify the general trends and development of research as it unfolded over years. The researchers hope that the policymakers, at both Faculty and University levels, will use the findings to improve research quality by boldly addressing the problems hampering research progress at AIKOL.

scholarly journals A review on the production, structure, bioactivities and applications of Tremella polysaccharides

2021 ◽  
Vol 35 ◽  
pp. 205873842110005
Author(s):  
Xia Ma ◽  
Meng Yang ◽  
Yan He ◽  
Chuntao Zhai ◽  
Chengliang Li
Keyword(s):  
Biologically Active ◽  
Research Progress ◽  
Research Trend ◽  
Production Structure ◽  
Health States ◽  
Preparation Methods ◽  
The Past ◽  
Structure Activity ◽  
Relationship Of ◽  
Active Natural

Tremella polysaccharide is known to be structurally unique and biologically active natural products, abundant and versatile in activities and applications in food industry, daily chemical industry and medicine industry. In order to improve the industrialisation of Tremella polysaccharide, the limitations of preparation and structure-activity relationship of Tremella polysaccharide were reviewed in this paper. The research progress of Tremella polysaccharide in the past 20 years was summarized from the sources, preparation methods, molecular structure, activity and application, and the research trend in the future was also prospected. The application prospect of Tremella polysaccharide in against multiple sub-health states was worth expecting.

scholarly journals Forensic Entomology in China and Its Challenges

Insects ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 230
Author(s):  
Yu Wang ◽  
Yinghui Wang ◽  
Man Wang ◽  
Wang Xu ◽  
Yanan Zhang ◽  
...  
Keyword(s):  
Species Identification ◽  
Forensic Entomology ◽  
Research Progress ◽  
Temperature Dependent ◽  
Related Research ◽  
Dependent Development ◽  
Faunal Succession ◽  
Recent Research Progress

While the earliest record of forensic entomology originated in China, related research did not start in China until the 1990s. In this paper, we review the recent research progress on the species identification, temperature-dependent development, faunal succession, and entomological toxicology of sarcosaprophagous insects as well as common applications of forensic entomology in China. Furthermore, the difficulties and challenges forensic entomologists face in China are analyzed and possible countermeasures are presented.

scholarly journals Research on the Literature of Green Building Based on the Web of Science: A Scientometric Analysis in CiteSpace (2002–2018)

2019 ◽  
Vol 11 (13) ◽  
pp. 3716 ◽  
Author(s):  
Yingling Shi ◽  
Xinping Liu
Keyword(s):  
Web Of Science ◽  
Green Building ◽  
Development Trend ◽  
Status Quo ◽  
Future Research ◽  
Building Industry ◽  
Scientometric Analysis ◽  
The Past ◽  
Evolution Pattern ◽  
The Status

Since the 21st century, the concept of green building has been gradually popularized and implemented in more countries, which has become a popular direction in the area of sustainability in the building industry. Over the past few decades, many scholars and experts have done extensive research on green building. The purpose of this paper is to systematically analyze and visualize the status quo of green building. Therefore, based on Web of Science (WoS), this paper analyzed the existing knowledge system of green building using CiteSpace, identified keywords related to green building and their frequency of occurrence using the function of keyword co-occurrence analysis, recognized five clusters using the function of cluster analysis, and explored the knowledge evolution pattern of green building using citation bursts analysis in order to reveal how research related to green building has evolved over time. On the basis of aforementioned keywords, clusters, and citation bursts analysis, this paper has built a knowledge graph for green building. This paper can help readers to better understand the status quo and development trend of green building and to easier recognize the shortcomings in the development of green building, so as to provide a promising direction for future research.

Resonant generation of electromagnetic surface wave by inhomogeneous relativistic electron stream

1981 ◽  
Vol 26 (3) ◽  
pp. 509-515 ◽  
Author(s):  
V. M. Čadež ◽  
S. Vuković ◽  
V. V. Frolov ◽  
A. Yu. Kyrie
Keyword(s):  
Surface Wave ◽  
Growth Rates ◽  
Doppler Effect ◽  
Maximal Growth ◽  
Electron Stream ◽  
Particle Flows ◽  
Anomalous Doppler Effect ◽  
Excitation Mechanisms ◽  
Resonant Generation ◽  
Cerenkov Effect

Generation of electromagnetic surface waves by relativistic inhomogeneous particle flows is investigated for plane and cylindrical geometries. The basic excitation mechanisms are shown to be the induced anomalous Doppler effect and the hydrodynamic Čerenkov effect. The relevant maximal growth rates may differ significantly from those derived for monoenergetic beams.

Recent Advances in the Study of Film Cooling on the Gas Turbine Blade

2014 ◽  
Vol 971-973 ◽  
pp. 143-147 ◽  
Author(s):  
Ping Dai ◽  
Shuang Xiu Li
Keyword(s):  
Gas Turbine ◽  
Turbine Blade ◽  
Film Cooling ◽  
Gas Turbines ◽  
High Performance ◽  
Leading Edge ◽  
Development Trend ◽  
Research Progress ◽  
Gas Turbine Blade ◽  
New Generation

The development of a new generation of high performance gas turbine engines requires gas turbines to be operated at very high inlet temperatures, which are much higher than the allowable metal temperatures. Consequently, this necessitates the need for advanced cooling techniques. Among the numerous cooling technologies, the film cooling technology has superior advantages and relatively favorable application prospect. The recent research progress of film cooling techniques for gas turbine blade is reviewed and basic principle of film cooling is also illustrated. Progress on rotor blade and stationary blade of film cooling are introduced. Film cooling development of leading-edge was also generalized. Effect of various factor on cooling effectiveness and effect of the shape of the injection holes on plate film cooling are discussed. In addition, with respect to progress of discharge coefficient is presented. In the last, the future development trend and future investigation direction of film cooling are prospected.

Research Progress on the Regulation Effect of Acupuncture on Intestinal Flora

2021 ◽  
Vol 46 (3) ◽  
pp. 191-200
Author(s):  
Tian-Qi Wang ◽  
Wan-Ting Lu ◽  
Jia Yang
Keyword(s):  
Drug Therapy ◽  
Intestinal Flora ◽  
Entry Point ◽  
Research Progress ◽  
Typical Representative ◽  
The Past ◽  
Acupuncture And Moxibustion ◽  
Regulation Effect ◽  
New Entry

More and more evidences show that the imbalance of intestinal flora is closely related to the occurrence of diseases. Through the regulation of intestinal microecology to prevent and treat diseases, it becomes a new entry point to treat diseases. As a typical representative of non-drug therapy, acupuncture and moxibustion plays an obvious role in regulating intestinal flora imbalance. This paper summarizes the effect and mechanism of acupuncture and moxibustion intervention on intestinal flora in the past ten years to provide more evidence for the treatment of diseases caused by intestinal flora imbalance.

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