摘要:ISAC(integrated sensing and communications) has been identified as one of the six typical application scenarios of the 6G mobile communication network. This puts higher requirements for the spatial resolution, anti-interference ability and sensing freedom of the antenna array in the future. To support the 6G high-performance ISAC, one approach is continue to increase the number of antennas which will inevitably increase the hardware cost, signal processing complexity, and energy consumption. On the other hand, sparse MIMO(multiple-input multiple-output) is a potential alternative. Compared with traditional compact MIMO, sparse MIMO can use the same number of array elements to achieve a larger aperture, thus providing finer spatial resolution. Therefore, this paper presents a comprehensive review of ISAC based on sparse MIMO. The basic array architecture of sparse MIMO is first introduced, and then the advantages including spatial resolution, communication rate, spatial multiplexing gain, channel capacity and gating lobe, and main challenge of sparse MIMO based wireless communication are discussed followed by sparse MIMO based wireless sensing. Finally,the huge potential of sparse MIMO on ISAC is introduced.
关键词:6G;integrated sensing and communications;multiple-input multiple-output
摘要:This paper investigates the signal tracking and prediction in the high-altitude air-to-air(A2A) ISAC scenario. First of all, an A2A ISAC system model is established, and state prediction and measurement models suitable for tracking are derived based on the spatial geometric relationship between two aircraft. Then, the model is linearized, and the traditional EKF algorithm is improved to an alternating EKF multi-beam tracking and prediction algorithm, which enables independent tracking and prediction of multiple targets. Furthermore, by reducing the order of the transformation matrix within the model, we further decrease the computational complexity. Utilizing the real-time state information provided by the alternating EKF tracking and prediction algorithm, we maximize the communication rate among multiple aircraft under power-constrained conditions through digital beamforming design, and we present a closed-form solution for the design. Simulation results demonstrate that the proposed algorithm significantly improves tracking accuracy while extending the time span of multi-target tracking and predictions.
关键词:high-altitude air-to-air;integrated sensing and communications;alternating EKF;tracking and prediction;beamforming design
摘要:This paper proposes a system design for integrated sensing, communication, and power transfer(ISCPT) which jointly addresses communication requirements, mobile energy device (MED) tracking, and energy replenishment. The proposed system enables a base station to simultaneously perform three functions: data communication, wireless power transfer, and sensing-based tracking. Specifically, the base station leverages downlink signals for simultaneous wireless power transfer, and efficient data communication, while employing their echoes to localize the MED. An iterative target tracking algorithm is developed, where the real-time posterior tracking error serves as a metric for sensing accuracy. An optimization problem is formulated to maximize real-time energy replenishment efficiency, subject to constraints on communication signal-to-noise ratio(SNR) and sensing error. The joint beamforming problem for communication, sensing, and power transfer, initially formulated as a non-convex optimization problem, is transformed into a convex one via semidefinite relaxation and the introduction of auxiliary variables. Simulation results demonstrate that the proposed algorithm significantly improves the system’s energy harvesting efficiency by jointly optimizing communication and power transfer beamforming. Furthermore, the sensing information is effectively leveraged to optimize both power transfer and communication links, thereby achieving the integrated fusion of communication, sensing, and energy replenishment.
关键词:integrated sensing,communication and power transfer;simultaneous wireless information and power transfer;6G;beamforming
摘要:In this paper,a ISAC(integrated sensing and communication) interference management approach based on user-grouping and non-orthogonal multiple access(NOMA) is proposed. Firstly, the distribution of communication users and sensing targets within the coverage of the base station through wireless signal sensing and group them based on the sensing targets is obtained. Secondly,NOMA is used to fully multiplex users in the power domain within the same group,and the orthogonality of spatial beams is used in different groups to reduce inter-group interference. Finally,a dual penalty based SCA iterative algorithm(DP-SCA) is proposed to solve the optimal beamformer with the goal of maximizing the weighted sum of communication users’ rates and sensing power. The simulation results show that, compared with non-grouped methods,the GF-NOMA method has an average system performance improvement of about 10%. At the same time,the impact of communication and sensing weight factors, penalty terms,and grouped user distribution on the system performance of the GF-NOMA interference management approach is evaluated .
摘要:This study establishes a theoretical thrust estimation model for microwave ion thrusters, conducts thrust measurements using a thrust stand, and analyzes errors of thrust. Additionally, it explores the effects of propellant flow rate, microwave power, and grid voltage on grid current and thrust. Results show that using a plume divergence correction coefficient of 0.98 and an ion energy correction coefficient of 1.02 improves the theoretical estimation model. Experimental investigations on thrust performance reveal that the influence of grid voltage aligns with theoretical predictions. Moreover, increasing microwave power and propellant flow rate significantly affects the ionization of Xe atoms in the discharge chamber,promoting ionization reactions and consequently impacting thrust performance.
关键词:gravitational wave;microwave ion thruster;thrust characteristics
摘要:For the downward stagnation pipeline system where cold and hot fluids converge, a three-dimensional pipeline system model was constructed using high-precision structured grid meshing technology.The influence mechanism of main-branch pipe temperature difference on turbulent intrusion phenomena near the tee junction was systematically investigated through the large eddy simulation(LES) turbulence model.The study revealed:The branch pipe inlet region exhibited significant temperature oscillation characteristics, with turbulent intrusion depth showing positive correlation with main-branch pipe temperature difference; Both temperature oscillations and fluid flow velocities in the bend section were significantly lower than those at the tee junction, confirming that the intensity of turbulent intrusion is suppressed by the intrusion depth; Distinct vortex shedding phenomena were observed in the near-wall region upstream of the branch pipe, where vortex transport and temperature fluctuation fields exhibited strong coupling characteristics in spatial distribution.
摘要:This study aims at optimizing the pre-treatment method for liposome and exosome derived from pancreatic cancer cells in transmission electron microscopy (TEM) to enhance imaging quality and preserve sample structural integrity. To overcome the challenges of poor contrast and structural vulnerability during TEM imaging for liposomes and exosomes, a thorough investigation of various pre-treatment methods was conducted, including filter membrane dust removal, agarose gel column purification, phosphotungstic acid (PTA) negative staining, vacuum heating drying, and extraction solution dilution. The morphological characteristics of liposomes and exosomes under these pre-treatment conditions were analyzed. Each of these pre-treatment methods was evaluated for its impact on the quality of TEM imaging and the preservation of the samples’ structural integrity. The results offer an insight for achieving more authentic and reliable TEM morphological characterizations, ensuring compliance with rigorous analytical standards. The results showed that, compared to the conventional PTA negative staining method, the imaging quality of liposome samples was improved after filter membrane dust removal and gel column purification. For exosome samples, optimizing PTA negative staining time and sample concentration could result in uniform distribution and distinct morphological features.
摘要:The aim of this study is to investigate the FAPα targeting prodrugs and anti-cancer characteristic of 1,2-disubstituted hydrazines. By bonding carbobenzoxy glycylprolyl (Z-GP-) on the diazinyl of 1,2-disubstituted hydrazines, two FAPα targeting prodrugs of novel 1,2-disubstituted hydrazines,including 2-carbobenzoxy glycylprol-yl-2-(4-methoxy)phenyl-1-(4-(N-isopropyl)aminoformyl)benzyl hydrazine (Z-GP-5a) and 2-carbobenzoxy glycylprolyl-2-(6-methoxy-2-yl) naphth-1-(4-(N-isopropyl)aminoformyl)benzyl hydrazine (Z-GP-5b) have been designed and synthesized. In vitro enzymatic hydrolysis model was set up to verify the cleavage possibility of Z-GP group. Mouse embryonic cells (NIH-3T3) and five common non-primary tumor cell lines including rat glioma cells (C6), mouse melanoma cells (K1735), human liver cancer cells (HepG-2), human breast cancer cells (MDA-MB-231), and murine melanoma cells (B16) were applied to confirm the toxicity-attenuation of both prodrugs. In vitro enzymatic hydrolysis experiments showed that Z-GP-5a and Z-GP-5b can be cleaved by recombinant human resource FAPα enzyme, releasing 2-(4-methoxy)phenyl-1-(4-(N-isopropyl)aminoformyl)benzyl hydrazine (5a) and 2-(6-methoxy-2-yl)naphth-1-(4-(N-isopropyl) aminoformyl)benzyl hydrazine (5b), respectively. This evidence preliminarily indicates the FAPα enzyme targeting characteristic of Z-GP-5a and Z-GP-5b. The cytotoxicity of Z-GP-5a and Z-GP-5b to NIH-3T3 showed less than that of 5a and 5b, respectively, implying the toxicity-attenuation of both prodrugs. By employing MTT assay, under the condition of 48-hour incubation, Z-GP-5a and Z-GP-5b were shown with less anti-cancer activity against five common non-primary tumor cell lines, which are C6, K1735, HepG-2, MDA-MB-231, and B16 than their respective parent compounds 5a and 5b. The anti-growth inhibition activity of Z-GP-5a to C6, K1735, and B16 was 1.23-, 2.06-, and 2.38-fold less than that of 5a, respectively; while to HepG-2 and MDA-MB-231, it was 9.95-, and 15.0-fold decrease, respectively. On the other hand, the anti-growth inhibition activity of Z-GP-5b to C6, MDA-MB-231, and B16 was 6.50-, 6.14-, and 13.0-fold less than that of 5b, respectively. All data support that Z-GP-5a and Z-GP-5b are the FAPα targeting prodrugs of their respective parent compounds 5a and 5b. It is expected to achieve the effect of reducing toxicity and increasing efficiency clinically.
摘要:Derivatives of Norathyriol were designed and synthesized in this study, and their phosphodiesterase4(PDE4) inhibitory activities were evaluated in vitro. Mangiferin was used as the starting material for structural modification, and sixteen derivatives were prepared through 2-deglycosylation,2,3-cyclic synthesis, and 6,7-substitution reactions and other methods. The PDE4 inhibitory activities of these compounds were evaluated in vitro by [3H] liquid scintillation counting method. Among these compounds, derivative 4 has the highest inhibitory activity (IC50=358 nmol/L). The docking display structure showed that the pyran ring could form hydrogen bonds with Gln-369, and the 6-methyl cyclopropane could form hydrophobic interactions with surrounding hydrophobic amino acids.
摘要:Changes in carbon storage are crucial for understanding terrestrial ecosystem dynamics. To investigate the changes in terrestrial ecosystem carbon storage, this study focused on the Ili region as the research area. Based on land use data from 2000 to 2020, the InVEST model was used to simulate the spatiotemporal characteristics of carbon storage in the study area. Geodetector and multiple regression residual analysis methods were employed to quantitatively analyze the driving factors affecting carbon storage and their contributions. The results indicate that: 1) From 2000 to 2020, the annual average carbon storage in the Ili region decreased by 8.89 Tg, showing a spatial distribution trend decreasing from the southern and northern mountainous areas towards the central plains. 2) The changes in carbon storage in the Ili region are affected by multiple factors, with elevation being the primary driving factor, having an explanatory power (q) of 0.469. The interaction between precipitation and the normalized difference vegetation index (NDVI) had the most significant impact on carbon storage. 3) The contributions of climate change and human activities to the increase in carbon storage in the Ili region were 48.16% and 51.84%, respectively. Areas where climate change contributed more than 80% were mainly distributed in the southern and northern forest regions, while areas where human activities contributed more than 80% were concentrated in the central and eastern parts. In regions where carbon storage decreased, approximately 8.60% of the reduction was caused by the combined effects of climate change and human activities, primarily located in the southern and northern forest regions. Overall, the areas with decreased carbon storage were significantly larger than those with increased carbon storage. The findings provide a scientific basis for carbon cycle research, carbon management policy formulation, and ecological protection in the Ili region.
关键词:carbon storage;InVEST model;geodetector;residual analysis;Ili region
摘要:The central trinomial coefficient denotes the coefficient of in the expansion of . We prove a congruence related to the sums of the central trinomial coefficient and the central binomial coefficient, which was conjectured by Z.-W. Sun.
关键词:supercongruences;central trinomial coefficients;central binomial coefficients;Fermat quotient;Legendre symbol
摘要:We show that the torsion module is in a Serre subcategory for the bounded below -complex . In addition, we prove the isomorphism in some case. As an application, the Betti number of a complex in a prime ideal can be computed by the Betti number of the local cohomology modules of in .
关键词:local cohomology;torsion functor;Serre subcategory;Betti number
摘要:The modified -differential Lie-Yamaguti algebras are considered, in which a modified -differential Lie-Yamaguti algebra consisting of a Lie-Yamaguti algebra and a modified -differential operator. First we introduce the representation of modified -differential Lie-Yamaguti algebras. Furthermore, we establish the cohomology of a modified -differential Lie-Yamaguti algebra with coefficients in a representation. Finally, we investigate the one-parameter formal deformations and Abelian extensions of modified -differential Lie-Yamaguti algebras using the second cohomology group.
关键词:Lie-Yamaguti algebra;modified -differential operator;representation and cohomology;one-parameter formal deformation;Abelian extension
摘要:In order to make the three-dimensional steady-state tropical climate model only have the trivial zero solution, sufficient conditions are obtained by using the energy estimation and Sobolev embedding, in which the integrability of the velocity field involves the anisotropy. The result obtained extends the known results with respect to Liouville theorem for three-dimensional steady-state tropical climate model.
摘要:A cross-diffusion predator-prey model with Crowley-Martin functional response and harvesting are studied. Firstly, the stable conditions of constant steady-state solutions and the conditions for cross-diffusion-driven Turing instability are obtained by the stability theory of linear operators. Moreover, the nonexistence and existence of non-constant positive steady-state solutions are discussed by using the energy estimation method and Leray-Schauder degree theory. Finally, the theoretical results are varified and supplemented by some numerical simulations. The results indicate that cross-diffusion has very important effects on the stability of constant positive steady-state solution and the existence of non-constant postive steady-state solutions, which can cause the formation of spatial patterns, and reasonable harvesting strategies can ensure the sustainable development of the populations.
摘要:The perfect edge state transfer on Cayley graphs over semi-dihedral groups is investigated. Using the representations and characters of , some necessary and sufficient conditions are given for admitting perfect edge state transfer of Cayley graphs over .
关键词:Cayley graphs;semi-dihedral groups;perfect edge state transfer;quantum random walk
摘要:We study the existence for component for positive solutions of -Laplacian equation boundary value problemwhere ,, and the nonnegative function . Under some suitable conditions, we show that there exists S-shaped component of positive solutions. The proof of our main result is based upon bifurcation.
摘要:Hepatitis E is an acute viral hepatitis mainly transmitted through the fecal-oral route. Based on the transmission mechanism of Hepatitis E, a SVEIRB Hepatitis E infectious disease model with vaccination and latent infections is constructed. Through the dynamic analysis of the model, the basic reproduction number of the model is determined. When , the disease-free equilibrium is globally asymptotically stable; when , the endemic equilibrium is globally asymptotically stable. Selecting the number of Hepatitis E patient cases in Shaanxi Province, the epidemic trend of Hepatitis E in the next few years is predicted through numerical simulation. Meanwhile, the partial rank correlation coefficient method is used to analyze the influence of different parameters on disease transmission. The results show that vaccination and environmental sanitation are the key factors affecting disease transmission. Therefore, by increasing the vaccination rate, strengthening environmental sanitation management and raising public health awareness, the transmission of the disease can be controlled effectively.