A study was conducted on the effect of time delay and structural parameters on the vibration reduction of a time delayed coupled negative stiffness dynamic absorber in nonlinear vibration reduction systems. Taking dyn...A study was conducted on the effect of time delay and structural parameters on the vibration reduction of a time delayed coupled negative stiffness dynamic absorber in nonlinear vibration reduction systems. Taking dynamic absorbers with different structural and control parameters as examples, the effects of third-order nonlinear coefficients, time-delay control parameters, and negative stiffness coefficients on reducing the replication of the main system were discussed. The nonlinear dynamic absorber has a very good vibration reduction effect at the resonance point of the main system and a nearby area, and when 1 increases to a certain level, the stable region of the system continues to increase. The amplitude curve of the main system of a nonlinear dynamic absorber will generate Hop bifurcation and saddle node bifurcation in the region far from the resonance point, resulting in almost periodic motion and jumping phenomena in the system. For nonlinear dynamic absorbers with determined structural parameters, time-delay feedback control can be adopted to control the amplitude of the main system. For different negative stiffness coefficients, there exists a minimum damping point for the amplitude of the main system under the determined system structural parameters and time-delay feedback control parameters.展开更多
HIV-associated neurocognitive disorders (HAND) are chronic complications of HIV infection in the central nervous system. Clinical presentations include asymptomatic neurocognitive impairment (ANI), mild neurocognitive...HIV-associated neurocognitive disorders (HAND) are chronic complications of HIV infection in the central nervous system. Clinical presentations include asymptomatic neurocognitive impairment (ANI), mild neurocognitive impairment (MND), and HIV-associated dementia (HAD). In the era of combination antiretroviral therapy (cART), the prevalence of HAD has significantly decreased, but the rates of ANI and MND have increased, impairing patients’ daily functioning, medical adherence, employment, driving abilities, risk of HIV transmission, overall quality of life, and posing challenges to society, economy, families, and public health. This article reviews the latest research findings regarding the pathogenesis, clinical diagnosis and treatment, neuroimaging, and neuropsychological assessment of HAND, aiming to provide insights into the prevention and management of HAND.展开更多
Research was conducted on topmouth culter (Culter alburnus) grown in ponds and lakes as well as wild types in order to determine their chemical composition and nutritional value. There are three types of fish that dif...Research was conducted on topmouth culter (Culter alburnus) grown in ponds and lakes as well as wild types in order to determine their chemical composition and nutritional value. There are three types of fish that differ in their proximate composition, amino acids, fatty acids, and minerals. Wild fish had a significantly lower crude lipid contents than cultured fish (P P ∑PUFAs) showed an obviously opposite trend. As compared with cultured fish, wild fish had significantly higher levels of n-3 PUFAs, arachidonic acid (AA), eicosapentaenoic acid (EPA) and docosahxaenoic acid (DHA) (P P > 0.05), except for Na, Fe and Se. In conclusion, diet composition and external aqueous environment may determine the differences between wild and cultured topmouth culter.展开更多
Two-dimensional(2D)ferromagnetic crystals with fascinating optical and electrical properties are crucial for nanotechnology and have a wide variety of applications in spintronics.However,low Curie temperatures of most...Two-dimensional(2D)ferromagnetic crystals with fascinating optical and electrical properties are crucial for nanotechnology and have a wide variety of applications in spintronics.However,low Curie temperatures of most 2D ferromagnetic crystals seriously hinder their practical applications,thus searching for intrinsic roomtemperature 2D ferromagnetic crystals is of great importance for development of information technology.Fortunately,progresses have been achieved in the last few years.Here we review recent advances in the field of intrinsic room-temperature 2D ferromagnetic crystals and introduce their applications in spintronic devices based on van der Waals heterostructures.Finally,the remaining challenge and future perspective on the development direction of intrinsic room-temperature 2D ferromagnetic crystals for 2D spintronics and van der Waals spintronics are briefly summarized.展开更多
文摘A study was conducted on the effect of time delay and structural parameters on the vibration reduction of a time delayed coupled negative stiffness dynamic absorber in nonlinear vibration reduction systems. Taking dynamic absorbers with different structural and control parameters as examples, the effects of third-order nonlinear coefficients, time-delay control parameters, and negative stiffness coefficients on reducing the replication of the main system were discussed. The nonlinear dynamic absorber has a very good vibration reduction effect at the resonance point of the main system and a nearby area, and when 1 increases to a certain level, the stable region of the system continues to increase. The amplitude curve of the main system of a nonlinear dynamic absorber will generate Hop bifurcation and saddle node bifurcation in the region far from the resonance point, resulting in almost periodic motion and jumping phenomena in the system. For nonlinear dynamic absorbers with determined structural parameters, time-delay feedback control can be adopted to control the amplitude of the main system. For different negative stiffness coefficients, there exists a minimum damping point for the amplitude of the main system under the determined system structural parameters and time-delay feedback control parameters.
基金financially supported by the National Key R&D Program of China (2022YFA1503400)the National Natural Science Foundation of China (21991091)+2 种基金the Key Projects of Shandong Key R&D plan (2019JZZY010506)Taishan Scholar Foundation (tspd20210308)the Petro China Research and Development Projects (2020A-1816 and 2020A-1817)。
文摘HIV-associated neurocognitive disorders (HAND) are chronic complications of HIV infection in the central nervous system. Clinical presentations include asymptomatic neurocognitive impairment (ANI), mild neurocognitive impairment (MND), and HIV-associated dementia (HAD). In the era of combination antiretroviral therapy (cART), the prevalence of HAD has significantly decreased, but the rates of ANI and MND have increased, impairing patients’ daily functioning, medical adherence, employment, driving abilities, risk of HIV transmission, overall quality of life, and posing challenges to society, economy, families, and public health. This article reviews the latest research findings regarding the pathogenesis, clinical diagnosis and treatment, neuroimaging, and neuropsychological assessment of HAND, aiming to provide insights into the prevention and management of HAND.
文摘Research was conducted on topmouth culter (Culter alburnus) grown in ponds and lakes as well as wild types in order to determine their chemical composition and nutritional value. There are three types of fish that differ in their proximate composition, amino acids, fatty acids, and minerals. Wild fish had a significantly lower crude lipid contents than cultured fish (P P ∑PUFAs) showed an obviously opposite trend. As compared with cultured fish, wild fish had significantly higher levels of n-3 PUFAs, arachidonic acid (AA), eicosapentaenoic acid (EPA) and docosahxaenoic acid (DHA) (P P > 0.05), except for Na, Fe and Se. In conclusion, diet composition and external aqueous environment may determine the differences between wild and cultured topmouth culter.
基金the National Key Research and Development Program of China(Grant No.2022YFE0134600)the National Natural Science Foundation of China(Grant Nos.52272152,61674063,and 62074061)+1 种基金the Foundation of Shenzhen Science and Technology Innovation Committee(Grant Nos.JCYJ20210324142010030 and JCYJ20180504170444967)the Fellowship of China Postdoctoral Science Foundation(Grant No.2022M711234)。
文摘Two-dimensional(2D)ferromagnetic crystals with fascinating optical and electrical properties are crucial for nanotechnology and have a wide variety of applications in spintronics.However,low Curie temperatures of most 2D ferromagnetic crystals seriously hinder their practical applications,thus searching for intrinsic roomtemperature 2D ferromagnetic crystals is of great importance for development of information technology.Fortunately,progresses have been achieved in the last few years.Here we review recent advances in the field of intrinsic room-temperature 2D ferromagnetic crystals and introduce their applications in spintronic devices based on van der Waals heterostructures.Finally,the remaining challenge and future perspective on the development direction of intrinsic room-temperature 2D ferromagnetic crystals for 2D spintronics and van der Waals spintronics are briefly summarized.
