查看更多>>摘要：In this paper,we describe an optical path stabilization method in order to keep the phase of the clock laser fixed during the interrogation.The phase noise along the optical path of the clock laser is extracted from the heterodyne beat signals.Then an acousto-optic modulator (AOM) driven by direct digital synthesizer (DDS) receives a feedback signal to cancel the phase noise.The experimental results show that our system can effectively suppress additional phase noise.The fractional frequency instability is dropped to 1.76×10-17 / τ at 1 s,which is improved by two orders of magnitude than before.In the case of Rabi excitation with a pulse duration T=50 ms,frequency shift is 7.9 mHz due to the feedback system relock process.For phase noise from different frequency,the system has a good suppression effect on low frequency phase noise.
查看更多>>摘要：All-trans-retinoic acid (atRA) plays an essential role in organ formation and differentiation,tissue cell proliferation,and apoptosis,and is closely related to the occurrence and development of various diseases.Liquid chromatography-tandem mass spectrometry (LC-MS/MS) has become a powerful tool for metabolic biological analysis because of the high sensitivity,specificity and throughput.We have developed a new method for the quantification of atRA by chemical derivatization with 2-nitrophe-nylhydrazine (2-NPH) for the first time,which reduced the interference of detection by changing the ion mass of the molecule.atRA from its endogenous geometric isomers,such as,9-cis-RA and 13-cis-RA,has been baseline resolved within 15 minute under the optimized chromatographic conditions.The method was applied to measure atRA in mouse serum and tissues including liver,kidney,brain,pancreas,and subcutaneous tissue.The method is easy to operate,highly sensitive and well selective,and can be used for accurate and rapid determination of atRA in biological samples.
查看更多>>摘要：Mesoporous hollow silica nanospheres (MHSNS) with an average diameter of 100 nm and wall thickness of approximately l0 nm were synthesized via core-shell structure of CaCO3@SiO2 by a one-pot route.Hollow silica nanospheres with mesoporous shell were obtained by dissolving CaCO3 in HCl dilute solution.The characterization of as-prepared hollow products by BET indicates that MHSNS have a specific surface area of 865 m2/g and a narrow pore size of 3.78 nm.
查看更多>>摘要：With the greatly increasing amount of discarded hydroxyl-terminated polybutadiene (HTPB) propellant year by year,it is of high significance to study the safe,efficient and environmental processing method of disposal HTPB propellant.In this paper,the decomposition agents are formulated for degrading the waste composite solid propellant.It is found that the following formulations of butanone 25％-55％,xylene 30％-75％,deionized water 40％-45％ have effective influence on the degradation of the waste composite solid propellant.The proper degradation time is found to be about 7-8 h.With the help of infrared spectrum analysis,scanning electron microscope imaging,thermogravimetric analysis and solvent viscosity test,it was proved that after degradation reaction on the propellant sometimes,a large number of irregular fractures occurred in bulk resulting from effective degradation.The characterization of the propellant after degradation showed that the hardness of the propellant decreased,the viscosity increased,and a large number of holes and cracks appeared on the surface.The results showed that the formulated degradation agent and degradation condition perform good degradation effects on HTPB solid propellant.
查看更多>>摘要：In order to study the effect of different recycled fine aggregate and recycled coarse aggregate substitution rate on the sulfate resistance of recycled concrete under dry-wet cycle conditions,the substitution rate of recycled fine aggregate and recycled coarse aggregate was designed to be 0％/0％,10％/0％,0％/25％,10％/25％,0％/50％ and 10％/50％ of the six groups of mixture ratio.The mass loss rate and relative dynamic modulus of each group of test blocks were tested respectively and the optimal ratio was selected.The Wiener distribution probability method was used to establish the reliability function to optimize the remaining life of the ratio.The results show that the dynamic elastic modulus and mass show a trend of increasing first and then decreasing during the dry-wet cycles of sulfate.The recycled concrete has the strongest resistance to sulfate attack under the substitution rate of recycled fine aggregate and recycled coarse aggregate is 10％ and 0％,and the test blocks will be damaged after being subjected to 182 times of dry-wet cycles of sulfate.The effect of recycled coarse aggregate on the sulfate attack resistance of the test block is more obvious than that of the recycled fine aggregate,which leads to the durability of the concrete being greatly reduced.
查看更多>>摘要：In this study,we assessed the relationship between life-style and prostate cancer.We selected the Gene Expression Omnibus (GEO) dataset GSE10306 to analyze the expression levels ofataxin10 (ATXN10),interferon related developmental regulator 1 (IFRD1),formin-binding protein 1 like (FNBP1L) and THO complex 2 (THOC2) in prostate biopsies pre and post intensive nutrition and lifestyle intervention.Following a three-month intervention of nutrition and lifestyle,these genes showed a significant down-regulation.ONCOMINE database analysis showed that the four genes exhibited high expression in prostate cancer tissues compared with normal prostate tissues,which indicated that comprehensive lifestyle changes may modify the progression of prostate cancer mediated by altering the expression of ATXN10,FNBP1L,THOC2 and IFRD1.Among the four genes,the high expression of IFRD1 was found to indicate a worse overall survival (OS) and disease-free survival (DFS).FNBP1L and THOC2 were associated with CD8+ T cell infiltration of prostate cancer.We also speculated a possible regulatory network for lifestyle to influence miRNA,subsequently influencing the expression of relevant genes.Our findings suggested that these genes may be used as potential target sites for the treatment of prostate cancer.
查看更多>>摘要：In this study,an altemative and cost-effective industrial byproduct phosphorus slag (PS) was utilized to treat simulated Cd-contaminated soil.The modified European Community Bureau of Reference (BCR) sequential extraction procedure was applied to assess the ability of PS to reduce Cd mobility in contaminated soil by the incubation experiments.The results showed 2％ (W/W) PS reduced the exchangeable fraction of Cd by 99.7％,which also increased the pH,electrical conductivity,cation exchange capacity,available phosphorus,and available silicon of the soil.The results suggested that the PS could decrease Cd bioavailability and improve soil nutrition.This was demonstrated by the pot experiments.The Cd accumulation in both pakchoi (Brassica chinensis L.) leaf and root was reduced along with the reduction of the Cd translocation factor (TF) and the bioaccumulation factors (BCF) in pakchoi.In Cd-contaminated soil (3.16 mg.kg-1),the 2％ (W/W) PS reduced the Cd content in the leaf and root of pakchoi by 70.7％ and 58.7％,respectively.Meanwhile,the increase of the chlorophyll content in pakchoi and the promotion of pakchoi root system development suggested healthy plant growth in the PS treated soil.
查看更多>>摘要：Aerodynamic noise is the main problem restricting its development nowadays in green energy,ocean engineering and aerospace engineering.In order to limit the aerodynamic noise of an airfoil structure,a method is proposed in this paper by designing low noise airfoils.This method optimized the aerodynamic noise of two-dimensional airfoil,and considered the aerodynamic performance of the airfoil at the same time.Based on Joukowski conformal transformation,airfoil geometry is pararneterized firstly.Then,the optimization model taking the lift-to-drag ratio and airfoil self-noise as the design objective,is established to modify the airfoil by active set algorithm until the airfoil can satisfy the design condition.Finally,the noise of the optimized airfoil is verified according to the prediction theory of airfoil noise.Moreover,the relationship between airfoil geometry and noise is analyzed.The results show that the lift-to-drag ratio of the optimized airfoil increased,and the noise also decreased.Thus,the optimization method can be used to address special design of low-noise airfoil.Besides,the optimization method in this paper can provide reference for improving lift-to-drag ratio and reducing noise of the airfoil in aircraft and submarine rudder system.
查看更多>>摘要：In recent years,the perceivable difference in observed and computed deflections for arch dams suggests the necessity to consider the side-load action of the hydrostatic pressure on reservoir basin (HPRB).In this paper,two additional Vogt coefficients with regard to the normal and angular deflections of arch dam foundation due to the action of HPRB are firstly elaborated,then an algorithm of the improved trial load method (ITLM) taking into account of conventional (six) and additional (two) Vogt coefficients is implemented.The elastic finite element method is employed as the bench mark in the verification of the improved method,which confirms that a better prediction of dam deflections and their gradient related stresses for arch dams may be provided by the ITLM taking into account of HPRB action.
查看更多>>摘要：In this paper,some basic properties of a new four-dimensional (4D) continuous autonomous chaotic system,in which each equation contains a cubic cross-product term,are further analyzed.The new system has 9 equilibria displaying graceful symmetry with respect to the origin and coordinate planes,and the stability of them are discussed.Then detailed bifurcation analysis is given to demonstrate the evolution processes of the system.Numerical simulations show that the system evolves chaotic motions through period-doubling bifurcation or intermittence chaos while the system parameters vary.We design a new scheme of generalized projective synchronization,so-called unified generalized projective synchronization,whose response signal synchronizes with the linear combination of drive signal.The design has the advantages of containing complete synchronization,anti-synchronization and disorder synchronization over the usual generalized projective synchronization,such that it can provide greater security in secure communication.Based on Lyapunov stability theorem,some sufficient conditions for the new synchronization are inferred.Numerical simulations demonstrate the effectiveness and feasibility of the method by employing the four-wing chaotic system.
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