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Life Origin in the Milky Way Galaxy: III. Spatial Distribution of Overheated Stars in the Solar Neighborhood
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作者 Alexander N. Safronov 《Journal of High Energy Physics, Gravitation and Cosmology》 CAS 2024年第2期693-709,共17页
A concept of ensemble averaged stellar reactors is developed to study the dynamics of processes occurring in stars, allocated in the ~200 pc solar neighborhood. According to the effective temperature value, four stell... A concept of ensemble averaged stellar reactors is developed to study the dynamics of processes occurring in stars, allocated in the ~200 pc solar neighborhood. According to the effective temperature value, four stellar classes are identified, for which the correlation coefficients and standard deviation are counted. The theory of the buoyancy terrestial elements is generalized to stellar systems. It was suggested that stars are over-heated due to the shift parameters of the nuclear processes occurring inside the stars, which leads to the synthesis of transuranium elements until the achievement of a critical nuclear mass and star explosion. The heavy transuranium elements sink downward and are concentrated in the stellar depth layers. The physical explanation of the existence of the critical Chandrasekhar star limit has been offered. Based on the spatial analysis of overheated stars, it was suggested that the withdrawal of the stellar reactor from the equilibrium state is a consequence of extragalactic compression inside the galaxy arm due to the arm spirality (not to be confused with the spirality of the galaxy itself). 展开更多
关键词 Stellar Nucleogenesis Ensemble-Averaged Stellar Reactor Overheated Stars Chandrasekhar Stellar Limit Arm spirality
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Recent advances in the application of MXenes for neural tissue engineering and regeneration
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作者 Menghui Liao Qingyue Cui +7 位作者 Yangnan Hu Jiayue Xing Danqi Wu Shasha Zheng Yu Zhao Yafeng Yu Jingwu Sun Renjie Chai 《Neural Regeneration Research》 SCIE CAS CSCD 2024年第2期258-263,共6页
Transition metal carbides and nitrides(MXenes)are crystal nanomaterials with a number of surface functional groups such as fluorine,hydroxyl,and oxygen,which can be used as carriers for proteins and drugs.MXenes have ... Transition metal carbides and nitrides(MXenes)are crystal nanomaterials with a number of surface functional groups such as fluorine,hydroxyl,and oxygen,which can be used as carriers for proteins and drugs.MXenes have excellent biocompatibility,electrical conductivity,surface hydrophilicity,mechanical properties and easy surface modification.However,at present,the stability of most MXenes needs to be improved,and more synthesis methods need to be explored.MXenes are good substrates for nerve cell regeneration and nerve reconstruction,which have broad application prospects in the repair of nervous system injury.Regarding the application of MXenes in neuroscience,mainly at the cellular level,the long-term in vivo biosafety and effects also need to be further explored.This review focuses on the progress of using MXenes in nerve regeneration over the last few years;discussing preparation of MXenes and their biocompatibility with different cells as well as the regulation by MXenes of nerve cell regeneration in two-dimensional and three-dimensional environments in vitro.MXenes have great potential in regulating the proliferation,differentiation,and maturation of nerve cells and in promoting regeneration and recovery after nerve injury.In addition,this review also presents the main challenges during optimization processes,such as the preparation of stable MXenes and long-term in vivo biosafety,and further discusses future directions in neural tissue engineering. 展开更多
关键词 HYDROGELS MXenes nerve regeneration neural cells neural stem cells ORGANOIDS spiral ganglion neurons
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Performance analysis of single-focus phase singularity based on elliptical reflective annulus quadrangle-element coded spiral zone plates
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作者 臧华平 王宝珍 +7 位作者 郑程龙 魏来 范全平 王少义 杨祖华 周维民 曹磊峰 郭海中 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第1期441-448,共8页
Optical vortices generated by the conventional vortex lens are usually disturbed by the undesired higher-order foci,which may lead to additional artifacts and thus degrade the contrast sensitivity. In this work, we pr... Optical vortices generated by the conventional vortex lens are usually disturbed by the undesired higher-order foci,which may lead to additional artifacts and thus degrade the contrast sensitivity. In this work, we propose an efficient methodology to combine the merit of elliptical reflective zone plates(ERZPs) and the advantage of spiral zone plates(SZPs) in establishing a specific single optical element, termed elliptical reflective annulus quadrangle-element coded spiral zone plates(ERAQSZPs) to generate single-focus phase singularity. Differing from the abrupt reflectance of the ERZPs, a series of randomly distributed nanometer apertures are adopted to realize the sinusoidal reflectance. Typically, according to our physical design, the ERAQSZPs are fabricated on a bulk substrate;therefore, the new idea can significantly reduce the difficulty in the fabrication process. Based on the Kirchhoff diffraction theory and convolution theorem, the focusing performance of ERAQSZPs is calculated. The results reveal that apart from the capability of generating optical vortices,ERAQSZPs can also integrate the function of focusing, energy selection, higher-order foci elimination, as well as high spectral resolution together. In addition, the focusing properties can be further improved by appropriately adjusting the parameters, such as zone number and the size of the consisted primitives. These findings are expected to direct a new direction toward improving the performance of optical capture, x-ray fluorescence spectra, and forbidden transition. 展开更多
关键词 optical vortex single-focus spiral zone plate topological charges
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Terahertz quasi-perfect vortex beam with integer-order and fractional-order generated by spiral spherical harmonic axicon
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作者 涂思语 刘德峰 +2 位作者 刘劲松 杨振刚 王可嘉 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第1期458-467,共10页
We propose a new method to generate terahertz perfect vortex beam with integer-order and fractional-order. A new optical diffractive element composed of the phase combination of a spherical harmonic axicon and a spira... We propose a new method to generate terahertz perfect vortex beam with integer-order and fractional-order. A new optical diffractive element composed of the phase combination of a spherical harmonic axicon and a spiral phase plate is designed and called spiral spherical harmonic axicon. A terahertz Gaussian beam passes through the spiral spherical harmonic axicon to generate a terahertz vortex beam. When only the topological charge number carried by spiral spherical harmonic axicon increases, the ring radius of terahertz vortex beam increases slightly, so the beam is shaped into a terahertz quasi-perfect vortex beam. Importantly, the terahertz quasi-perfect vortex beam can carry not only integer-order topological charge number but also fractional-order topological charge number. This is the first time that vortex beam and quasi-perfect vortex beam with fractional-order have been successfully realized in terahertz domain and experiment. 展开更多
关键词 TERAHERTZ spiral spherical harmonic axicon quasi-perfect vortex beam topological charge number
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Low Surface Brightness Galaxies Selected by Different Model Fitting
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作者 Bing-Qing Zhang Hong Wu +3 位作者 Wei Du Pin-Song Zhao Min He Feng-Jie Lei 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2024年第1期223-236,共14页
We present a study of low surface brightness galaxies(LSBGs) selected by fitting the images for all the galaxies inα.40 SDSS DR7 sample with two kinds of single-component models and two kinds of two-component models(... We present a study of low surface brightness galaxies(LSBGs) selected by fitting the images for all the galaxies inα.40 SDSS DR7 sample with two kinds of single-component models and two kinds of two-component models(disk+bulge):single exponential,single sersic,exponential+deVaucular(exp+deV),and exponential+sérsic(exp+ser).Under the criteria of the B band disk central surface brightness μ_(0,disk)(B)≥22.5 mag arcsec^(-2) and the axis ratio b/a> 0.3,we selected four none-edge-on LSBG samples from each of the models which contain 1105,1038,207,and 75 galaxies,respectively.There are 756 galaxies in common between LSBGs selected by exponential and sersic models,corresponding to 68.42% of LSBGs selected by the exponential model and 72.83% of LSBGs selected by the sersic model,the rest of the discrepancy is due to the difference in obtaining μ_(0) between the exponential and sersic models.Based on the fitting,in the range of 0.5≤n≤1.5,the relation of μ_(0) from two models can be written as μ_(0,sérsic)-μ_(0,exp)=-1.34(n-1).The LSBGs selected by disk+bulge models(LSBG_(2)comps) are more massive than LSBGs selected by single-component models(LSBG_1comp),and also show a larger disk component.Though the bulges in the majority of our LSBG_(2)comps are not prominent,more than 60% of our LSBG_(2)comps will not be selected if we adopt a single-component model only.We also identified 31 giant low surface brightness galaxies(gLSBGs) from LSBG_(2)comps.They are located at the same region in the color-magnitude diagram as other gLSBGs.After we compared different criteria of gLSBGs selection,we find that for gas-rich LSBGs,M_(*)> 10^(10)M_⊙ is the best to distinguish between gLSBGs and normal LSBGs with bulge. 展开更多
关键词 catalogs galaxies:spiral galaxies:bulges methods:data analysis methods:statistical
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Fusion of Spiral Convolution-LSTM for Intrusion DetectionModeling
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作者 Fei Wang Zhen Dong 《Computers, Materials & Continua》 SCIE EI 2024年第5期2315-2329,共15页
Aiming at the problems of low accuracy and slow convergence speed of current intrusion detection models,SpiralConvolution is combined with Long Short-Term Memory Network to construct a new intrusion detection model.Th... Aiming at the problems of low accuracy and slow convergence speed of current intrusion detection models,SpiralConvolution is combined with Long Short-Term Memory Network to construct a new intrusion detection model.The dataset is first preprocessed using solo thermal encoding and normalization functions.Then the spiral convolution-Long Short-Term Memory Network model is constructed,which consists of spiral convolution,a two-layer long short-term memory network,and a classifier.It is shown through experiments that the model is characterized by high accuracy,small model computation,and fast convergence speed relative to previous deep learning models.The model uses a new neural network to achieve fast and accurate network traffic intrusion detection.The model in this paper achieves 0.9706 and 0.8432 accuracy rates on the NSL-KDD dataset and the UNSWNB-15 dataset under five classifications and ten classes,respectively. 展开更多
关键词 Intrusion detection deep learning spiral convolution long and short term memory networks 1D-spiral convolution
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The GBR Hypothesis Revisited
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作者 Lewis Nash 《Journal of High Energy Physics, Gravitation and Cosmology》 CAS 2024年第2期800-809,共10页
The radical hypothesis concerning the physics of gravitational black-body radiation is placed on a more solid statistical mechanics foundation in this study. As the concepts and formalism in the former presentation ar... The radical hypothesis concerning the physics of gravitational black-body radiation is placed on a more solid statistical mechanics foundation in this study. As the concepts and formalism in the former presentation are only partially developed and furthermore, suffer from an unfortunate misstep regarding Hawking radiation and the hypothetical gravitational black-body temperature of a parcel or distribution of energy;this paper aims to fill in some of the theoretical gaps in the derivation of the Planck radiation formula for gravity (or non-Euclidean space-time), and there by provide a more complete and transparent quantum theory of thermal gravitational radiation. 展开更多
关键词 Gravitational Black Body GRAVITONS Thermal Gravitational Radiation Spiral Galaxy Rotation Curves
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Particulate flow modelling in a spiral separator by using the Eulerian multi-fluid VOF approach 被引量:2
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作者 Lingguo Meng Shuling Gao +4 位作者 Dezhou Wei Qiang Zhao Baoyu Cui Yanbai Shen Zhenguo Song 《International Journal of Mining Science and Technology》 SCIE EI CAS CSCD 2023年第2期251-263,共13页
The Euler-Euler model is less effective in capturing the free surface of flow film in the spiral separator,and thus a Eulerian multi-fluid volume of fluid(VOF)model was first proposed to describe the particulate flow ... The Euler-Euler model is less effective in capturing the free surface of flow film in the spiral separator,and thus a Eulerian multi-fluid volume of fluid(VOF)model was first proposed to describe the particulate flow in spiral separators.In order to improve the applicability of the model in the high solid concentration system,the Bagnold effect was incorporated into the modelling framework.The capability of the proposed model in terms of predicting the flow film shape in a LD9 spiral separator was evaluated via comparison with measured flow film thicknesses reported in literature.Results showed that sharp air–water and air-pulp interfaces can be obtained using the proposed model,and the shapes of the predicted flow films before and after particle addition were reasonably consistent with the observations reported in literature.Furthermore,the experimental and numerical simulation of the separation of quartz and hematite were performed in a laboratory-scale spiral separator.When the Bagnold lift force model was considered,predictions of the grade of iron and solid concentration by mass for different trough lengths were more consistent with experimental data.In the initial development stage,the quartz particles at the bottom of the flow layer were more possible to be lifted due to the Bagnold force.Thus,a better predicted vertical stratification between quartz and hematite particles was obtained,which provided favorable conditions for subsequent radial segregation. 展开更多
关键词 Spiral separator Computational fluid dynamics(CFD) Eulerian multi-fluid VOF model Bagnold effect Particulate flow
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Asymmetrical spiral spectra and orbital angular momentum density of non-uniformly polarized vortex beams in uniaxial crystals 被引量:1
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作者 舒凌云 程科 +2 位作者 廖赛 梁梦婷 杨嶒浩 《Chinese Physics B》 SCIE EI CAS CSCD 2023年第2期323-331,共9页
To explore the effect of non-uniform polarization on orbital angular momentum(OAM) in anisotropic medium, in this work investigated are the evolution of the spiral spectra and OAM densities of non-uniformly polarized ... To explore the effect of non-uniform polarization on orbital angular momentum(OAM) in anisotropic medium, in this work investigated are the evolution of the spiral spectra and OAM densities of non-uniformly polarized vortex(NUPV)beams in uniaxial crystals propagating orthogonal to the optical axis, and also the case of uniformly polarized vortex(UPV)beams with left-handed elliptical polarization. In the input plane, the NUPV beams present their spiral spectra of m-mode concentrated at m = l ± 1 modes rather than m = l mode, and reveal the relation among topological charge l, mode of spiral spectra m and the power weight value Rmexpressed by l=∑^(∞)_(m)=-∞Rm. is still satisfied for UPV beams in uniaxially anisotropic crystals, whereas for NUPV beams their relations are no longer valid owing to non-uniform polarization. Furthermore, the analysis indicates that the asymmetrical distribution of power weight of spiral spectra and the non-zero value in the sum of longitudinal OAM densities originate from the initial non-uniform polarization and anisotropy in uniaxial crystals rather than topological charges. In addition, the relation between spiral spectrum and longitudinal OAM density is numerically discussed. This work may provide an avenue for OAM-based communications,optical metrology, and imaging by varying the initial non-uniform polarization. 展开更多
关键词 non-uniformly polarized beams spiral spectrum spin angular momentum orbital angular momentum VORTEX
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Difference of anterior and posterior orbital development in patients with congenital microphthalmia:a retrospective cohort study from China 被引量:1
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作者 Ju Zhang Zhi-Jia Hou +2 位作者 Jun-Fang Xian Qing-Lin Chang Dong-Mei Li 《International Journal of Ophthalmology(English edition)》 SCIE CAS 2023年第3期411-417,共7页
AIM:To evaluate volume differences between anterior and posterior orbit and demographic characteristics of Chinese patients with congenital microphthalmia.METHODS:A retrospective cohort study,involving 169 unilateral ... AIM:To evaluate volume differences between anterior and posterior orbit and demographic characteristics of Chinese patients with congenital microphthalmia.METHODS:A retrospective cohort study,involving 169 unilateral congenital microphthalmia patients aged between 1 and 57 years old was conducted.Three-dimensional images of the orbit were generated from past CT scans,and digital orbital volume comprehensive measurement was done.The measured data included orbital volume(OBV),posterior orbital volume(POV),orbital width(OBW),orbital height(OBH),orbital depth(OBD),and posterior orbital area ratio.RESULTS:Significant differences were observed among OBV,POV,OBW,OBH,and OBD of the affected and unaffected eyes in different age-based groups(all P<0.001).Among them,OBH had the greatest different.The mean microphthalmic to contralateral ratio(MCR) of OBV,POV,OBW,and OBH continuously increased from 1 to 3 years old,whereas the MCR of POV decreased from 3 to 17 years old.The MCR of OBD was not found to be correlated to age.There was no significant difference between OBV,POV,OBW,and OBH in ages from 13 years old to adulthood(all P>0.05).The difference in posterior orbital area ratio between the affected and unaffected groups was not statistically significant(P>0.05).CONCLUSION:OBH is maximally affected,whereas OBD is minimally affected by microphthalmia.Posterior orbital retardation began 2y prior to orbital retardation and occurred at 3 years old in the affected eye,suggesting that intervention therapy should be done before the age of 4. 展开更多
关键词 orbital measurement congenital microphthalmia tomography spiral computed
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Efficacy of multi-slice spiral computed tomography in evaluating gastric cancer recurrence after endoscopic submucosal dissection 被引量:1
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作者 Jian-Jun Yin Xiao Hu +1 位作者 Sen Hu Guo-Hong Sheng 《World Journal of Gastrointestinal Oncology》 SCIE 2023年第9期1636-1643,共8页
BACKGROUND Recurrence is the major challenge facing endoscopic submucosal dissection(ESD)-based treatment therapies for early gastric cancer(EGC).Urgent development of simple and easy surveillance approaches will enha... BACKGROUND Recurrence is the major challenge facing endoscopic submucosal dissection(ESD)-based treatment therapies for early gastric cancer(EGC).Urgent development of simple and easy surveillance approaches will enhance clinical treatment of the disease.AIM To explore the role of computed tomography(CT)recurrence in evaluating EGC after ESD treatment.METHODS We retrospectively recruited patients from our endoscopy department,between January 2002 and December 2015,and analyzed their basic characteristics,including symptoms,CT results,and results of endoscopy with biopsy,among others.RESULTS Among a total of 2150 patients EGC patients surveyed,1362 met our inclusion and exclusion criteria and were therefore enrolled in our study.The cohort’s sensitivity of CT for recurrent GC and specificity were 44.22%and 43.86%,respectively,with negative and positive predictive values of 40.15%(275/685)and 48.01%(325/677),respectively.The area under the curve of arterial and venous CT values for recurrent EGC were 0.545,and 0.604,respectively.Receiver operating characteristic curve revealed no statistically significant differences between arterial and venous CT values for recurrent EGC.CONCLUSION Enhanced CT has superior diagnostic efficacy,but less accuracy,compared to gold standard techniques in patients with recurrent EGC. 展开更多
关键词 Computed tomography Early gastric cancer Gastric cancer Multi-slice spiral computed tomography
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Portal vein computed tomography imaging characteristics and their relationship with bleeding risk in patients with liver cirrhosis undergoing interventional therapy 被引量:1
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作者 Xue-Jing Song Jing-Lei Liu +1 位作者 Shu-Ya Jia Kai Zhang 《World Journal of Clinical Cases》 SCIE 2023年第18期4277-4286,共10页
BACKGROUND This study aimed to analyze the predictive value of multi-slice spiral computed tomography(CT)perfusion imaging for upper gastrointestinal bleeding in patients with cirrhotic portal hypertension.A total of ... BACKGROUND This study aimed to analyze the predictive value of multi-slice spiral computed tomography(CT)perfusion imaging for upper gastrointestinal bleeding in patients with cirrhotic portal hypertension.A total of 62 patients with cirrhotic portal hypertension and 28 healthy individuals were included.The results showed that multi-slice spiral CT perfusion imaging had a significant predictive value for upper gastrointestinal bleeding in patients with cirrhotic portal hypertension.The vascular area,number of vascular cross-sections,and gastric coronary vein diameter(GCVD)showed high predictive values,with the vascular area having the best predictive value.AIM To investigate the predictive accuracy of multi-slice spiral CT perfusion imaging for upper gastrointestinal bleeding in patients with cirrhosis and portal hypertension.METHODS This study included 62 patients with cirrhotic portal hypertension(disease group)and 28 healthy individuals(control group).The disease group was further divided into two subgroups:Group A(n=27,bleeding)and group B(n=35,no bleeding).All patients underwent multi-slice spiral CT perfusion imaging at our hospital,and we compared various parameters such as liver blood flow,vein size,number of blood vessels,and blood vessel area between the two groups.We employed statistical analysis to identify factors associated with upper gastrointestinal bleeding and created a graph comparing the predictive value of different factors for bleeding.RESULTS We found no difference in hepatic artery(HAP)levels among the three groups(all P>0.05).The portal vein levels in groups A and B were much lower than in the control group;group A was much lower than group B(all P<0.05).The HAP perfusion index levels in groups A and B were much higher than in the control group;group A was much higher than group B(all P<0.05).The portal vein diameter,splenic vein diameter,and GCVD levels in groups A and B were much higher than in the control group;those in group A were much higher than those in group B(all P<0.05).The number of blood vessels and blood vessel area in groups A and B were much higher than in the control group;those in group A were much higher than those in group B(all P<0.05).The statistical method showed a strong link between GCVD,number of blood vessels,blood vessel area,and upper gastrointestinal bleeding(odds ratio=1.275,1.346,1.397,P<0.05).The graph showed that GCVD,number of blood vessels,and blood vessel area could predict bleeding well,with blood vessel area having the best prediction power.CONCLUSION That multi-slice spiral CT perfusion imaging can predict upper gastrointestinal bleeding well in patients with cirrhosis and high blood pressure in the portal vein.GCVD,number of blood vessels,and blood vessel area had high prediction power.The blood vessel area had the best prediction power,with an area under the curve of 0.831. 展开更多
关键词 Multi-slice spiral computed tomography PERFUSION CIRRHOSIS Portal hypertension Upper gastrointestinal bleeding Predictive value
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Cosmic Contributions to the Deposition of Petroleum Source Rocks: Review and Analysis 被引量:1
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作者 Heinz-Jürgen Brink 《International Journal of Geosciences》 2023年第11期1123-1145,共23页
The development of globally distributed Phanerozoic petroleum source rocks is concentrated on time intervals, which correlate convincingly with climatic driven glaciation epochs of Earth’s history, repeated every 150... The development of globally distributed Phanerozoic petroleum source rocks is concentrated on time intervals, which correlate convincingly with climatic driven glaciation epochs of Earth’s history, repeated every 150 million years, and during sea level high stands and maxima of global magmatism with a period of 300 million years. The 150 million year periodicity appears to be related to the path of the solar system through the spiral arms of the Milky Way and the 300 million year periodicity to changes of the spiral system. The spiral arms are preferred birth places of new stars, of which the larger ones have only smaller lifespans. Their preliminary deaths ended with explosions and selectively with the development of so-called white dwarfs, neutron stars or black holes. The times of the explosions of intermediate (sun-like) stars can be determined by measuring the present brightness of the dwarfs. Not surprisingly the last two maxima of recordable near solar system star explosions took place during the presumably spiral arms driven glacial epochs in Eocene to present and Upper Jurassic times. Such near solar system star explosions may have been the source of intense neutrino showers, cosmic rays and star dust. This dust contained all kinds of chemical elements, including phosphorus and uranium. Such cosmic phosphorus may have supported, through fertilizing, the distribution of life on Earth additionally to local phosphorus resources via bloom of biota in lakes and oceans and the enhanced growth of plants on land across all climatic zones. Subsequently it maintained the development of petroleum source rocks of all organic matter types within black shales and coals. Via the distribution of remnants of exploding stars—mainly white dwarfs, but neutron stars and black holes have to be counted as well—a cosmic contribution can therefore casually linked to the deposition of petroleum source rocks on Earth, not only purely correlatively by their contemporaneous appearances. 展开更多
关键词 Cosmic Rays Cosmic Dust Milky Way Spiral Arms STARS Phosphorus URANIUM Petroleum Source Rock
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Helical particle manipulation based on power-exponent-phase acoustic vortices generated by a sector transducer array
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作者 王青东 胡彦涛 +1 位作者 王胜利 李洪宇 《Chinese Physics B》 SCIE EI CAS CSCD 2023年第6期333-341,共9页
The characteristics of traditional acoustic vortices(AVs) were verified by the cross-sectional axisymmetric pressure distributions with perfect phase spirals around the center pressure null. In order to generate a non... The characteristics of traditional acoustic vortices(AVs) were verified by the cross-sectional axisymmetric pressure distributions with perfect phase spirals around the center pressure null. In order to generate a non-axisymmetric pressure distribution, the concept of power-exponent-phase was first introduced into the formation of AV beams, named “powerexponent-phase acoustic vortices(PAVs)” in this paper. Based on a ring-array of sector transducers, the helical distribution of the low-pressure valley in cross-sections of PAVs, which enables particles to move from a distant position to the center low-potential well along a certain spiral passageway, was proved theoretically. The particle manipulation behavior for PAVs with a power order of 2 is numerically modeled and experimentally confirmed. The results show that PAVs with a nonaxisymmetric spiral pressure distribution can be used to realize the directional transport of particles in an enlarged scope,suggesting prospective application potential in biomedical engineering. 展开更多
关键词 acoustic vortices power-exponent-phase spiral potential well sector transducer array particle manipulation
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Numerical simulation of flow and heat transfer of n-decane in sub-millimeter spiral tube at supercritical pressure
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作者 Jiahao Xing Huaizhi Han +1 位作者 Ruitian Yu Wen Luo 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2023年第8期173-185,共13页
The flow and heat transfer characteristics of n-decane in the sub-millimeter spiral tube(SMST) at supercritical pressure(p = 3 MPa) are studied by the RNG k-ε numerical model in this paper. The effects of various Rey... The flow and heat transfer characteristics of n-decane in the sub-millimeter spiral tube(SMST) at supercritical pressure(p = 3 MPa) are studied by the RNG k-ε numerical model in this paper. The effects of various Reynolds numbers(Re) and structural parameters pitch(s) and spiral diameter(D) are analyzed.Results indicate that the average Nusselt numberNu and friction factorNu increase with an increase in Re, and decrease with an increase in D/d(tube diameter). In terms of the structural parameter s/d, it is found that as s/d increases, the Nu first increase, and then decrease. and the critical structural parameter is s/d = 4. Compared with the straight tube, the SMST can improve Nu by 34.8% at best, while it can improve Nu by 102.1% at most. In addition, a comprehensive heat transfer coefficient is applied to analyze the thermodynamic properties of SMST. With the optimal structural parameters of D/d = 6 and s/d = 4, the comprehensive heat transfer factor of supercritical pressure hydrocarbon fuel in the SMST can reach 1.074. At last, correlations of the average Nusselt number and friction factor are developed to predict the flow and heat transfer of n-decane at supercritical pressure. 展开更多
关键词 Sub-millimeter spiral tube Supercritical pressure Numerical simulation Heat transfer performance
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Sound absorbing properties of spiral metasurfaces inspired by micro-perforated plates
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作者 Han Zhang Pengxiang Hao +4 位作者 Huilan Wu Zhenyuan Lin Chengpeng Hao Zhengpan Qi Ning Hu 《Theoretical & Applied Mechanics Letters》 CAS CSCD 2023年第3期209-215,共7页
As a kind of classical low-frequency sound-absorbing material,the microperforated plate(MPP)has been widely used.Here,we inspired by the sound absorption mechanism of the MPP,a spiral metasurface(SM)is designed and th... As a kind of classical low-frequency sound-absorbing material,the microperforated plate(MPP)has been widely used.Here,we inspired by the sound absorption mechanism of the MPP,a spiral metasurface(SM)is designed and the analytical solution of acoustic impedance and sound absorption coefficient are obtained.The relationship between the sound absorption properties of the MPP and the SM with their own structures is systematically studied,and the analytical solutions are used to optimise the structure.It is concluded that the MPP and the SM of the same thickness achieve effective absorption in the frequency range between 390-900 Hz and 1920-4266 Hz,with a total thickness less than 1/6 of the wavelength.Meanwhile,the numerical calculation shows that the MPP and SM can match well with the background medium in the effective rang.Our study provides new insights into the design methods of sound-absorbing materials and is potentially suitable for many acoustic engineering applications. 展开更多
关键词 Microperforated plates Spiral metasurfaces Sound-absorbing properties Equivalent dispersion
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Inhibition of histone methyltransferase PRMT5 attenuates cisplatininduced hearing loss through the PI3K/Akt-mediated mitochondrial apoptotic pathway
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作者 Zhiwei Zheng Benyu Nan +5 位作者 Chang Liu Dongmei Tang Wen Li Liping Zhao Guohui Nie Yingzi He 《Journal of Pharmaceutical Analysis》 SCIE CAS CSCD 2023年第6期590-602,共13页
This study aimed to evaluate the therapeutic potential of inhibiting protein arginine methyltransferase 5(PRMT5)in cisplatin-induced hearing loss.The effects of PRMT5 inhibition on cisplatin-induced auditory injury we... This study aimed to evaluate the therapeutic potential of inhibiting protein arginine methyltransferase 5(PRMT5)in cisplatin-induced hearing loss.The effects of PRMT5 inhibition on cisplatin-induced auditory injury were determined using immunohistochemistry,apoptosis assays,and auditory brainstem response.The mechanism of PRMT5 inhibition on hair cell survival was assessed using RNA-seq and Cleavage Under Targets and Tagment-quantitative polymerase chain reaction(CUT&Tag-qPCR)analyses in the HEI-OC1 cell line.Pharmacological inhibition of PRMT5 significantly alleviated cisplatin-induced damage to hair cells and spiral ganglion neurons in the cochlea and decreased apoptosis by protecting mitochondrial function and preventing the accumulation of reactive oxygen species.CUT&Tag-qPCR analysis demonstrated that inhibition of PRMT5 in HEI-OC1 cells reduced the accumulation of H4R3me2s/H3R8me2s marks at the promoter region of the Pik3ca gene,thus activating the expression of Pik3ca.These findings suggest that PRMT5 inhibitors have strong potential as agents against cisplatininduced ototoxicity and can lay the foundation for further research on treatment strategies of hearing loss. 展开更多
关键词 Protein arginine methyltransferase 5 (PRMT5) LLY-283 CISPLATIN Hearing loss Hair cell Spiral ganglion neuron
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Numerical Analysis of the Erosion Mechanism inside the Tube Sockets of Main Steam Thermometers in a Coal-Fired Power Plant
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作者 Yukun Lv Fan Yang +1 位作者 Zi’an Wei Quan Lu 《Fluid Dynamics & Materials Processing》 EI 2023年第2期379-397,共19页
Leakage occurring in the tube sockets of the main steam thermometers can seriously threaten the safe operation of coal-fired power plants.Here,assuming a 300 MW unit as a relevant testbed,this problem is investigated ... Leakage occurring in the tube sockets of the main steam thermometers can seriously threaten the safe operation of coal-fired power plants.Here,assuming a 300 MW unit as a relevant testbed,this problem is investigated numerically through solution of the equations of fluid-dynamics in synergy with the mathematical treatment of relevant statistics.The results indicate that the steam can form a large-scale spiral flow inside the tube socket and continuously scour the inner wall.In the model with the protective casing setting angle of 60°,the average tangential fluid velocity can reach up to 4.8 m/s,which is about twice higher than that in the model with the protective casing setting angle of 0°.The wake disturbance generated by the flow around the thermo-sensitive body leads to differences in the fluid motion inside the tube sockets between the upstream and downstream thermometers.These differences are affected by the distance between the thermometers,the setting angle of protective casing,and other factors.The pressure of the main steam inside the tube socket for a R3 thermometer,located outside the curved pipeline,is about 1756 Pa higher than that of the L3 thermometer located outside the straight pipeline,indicating that the secondary flow generated in the curved pipeline is able to provide stronger energy for the large-scale spiral flow inside the tube socket.On the basis of these findings,an improvement scheme for the installation of long-itudinal ribs in the tube sockets is proposed.The simulation results show that the average tangential velocity of the fluid within the near-wall area of tube sockets decreases by more than 90%,which should be enough to effectively alleviate the damage to the inner wall caused by high-pressure fluid or particles. 展开更多
关键词 Metal wear fluid scouring spiral flow average statistics method numerical simulation
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CFD Analysis of Spiral Flow Fields in Proton Exchange Membrane Fuel Cells
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作者 Jian Yao Fayi Yan Xuejian Pei 《Fluid Dynamics & Materials Processing》 EI 2023年第6期1425-1445,共21页
Proton exchange membrane fuel cells(PEMFCs)are largely used in various applications because of their pollution-free products and high energy conversion efficiency.In order to improve the related design,in the present ... Proton exchange membrane fuel cells(PEMFCs)are largely used in various applications because of their pollution-free products and high energy conversion efficiency.In order to improve the related design,in the present work a new spiral flow field with a bypass is proposed.The reaction gas enters the flow field in the central path and diffuses in two directions through the flow channel and the bypass.The bypasses are arranged incrementally.The number of bypasses and the cross-section size of the bypasses are varied parametrically while a single-cell model of the PEMFC is used.The influence of the concentration of liquid water and oxygen in the cell on the performance of different flow fields is determined by means of Computational fluid dynamics(COMSOL Multiphysics software).Results show that when the bypass number is 48 and its cross-sectional area is 0.5 mm^(2),the cell exhibits the best performances. 展开更多
关键词 Proton exchange membrane fuel cells(PEMFCs) new spiral flow field square plate CFD simulation analysis
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The Gastropod Shell Structure as a Blueprint for a Periodic System: A New Theory for Element Configurations
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作者 Nader Butto 《Journal of Biophysical Chemistry》 CAS 2023年第2期31-58,共28页
The purpose of this article is to propose a new design for the periodic table of elements. The new design is based on a three-dimensional (3D) model of the gastropod shell structure and presents a mechanism of the for... The purpose of this article is to propose a new design for the periodic table of elements. The new design is based on a three-dimensional (3D) model of the gastropod shell structure and presents a mechanism of the formation of elements that reflects the laws of nature that guide the formation of the gastropod shell, electron orbitals, and element structure. The author also identifies challenges associated with the current standard periodic table, such as the positions of hydrogen, helium, lanthanides, and actinides. The author’s research is a response to the IUPAC’s request, dating back to 2016, to settle unresolved disputes surrounding the current standard periodic table. Hence, the author proposes the “Gastropod Shell Model”, which presents the periodic system in 2D and 3D snail shells based on a hypothesized unifying principle guiding the formation of elements: the universal unified theory that considers the spiral and vortex forms as the bridge between energy and matter. The author was able to position hydrogen, helium, lanthanides, and actinides uniquely in their proposed periodic system to solve problems associated with their positions in the standard periodic table. Readers will be interested in uncovering the “hypothesized unifying principle guiding the formation of elements”. 展开更多
关键词 3D Periodic Table Gastropod Shell Spiral Model
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