Since solid pseudopapillary tumor of the pancreas(SP-TP) was officially classified by the World Health Org-anization in 1996,SPTP has recently received special attention in the literature.Studies have shown that SPTP ...Since solid pseudopapillary tumor of the pancreas(SP-TP) was officially classified by the World Health Org-anization in 1996,SPTP has recently received special attention in the literature.Studies have shown that SPTP is a heterogeneous tumor,with a small percentage of patients harboring aggressive behaviors.However,cri-teria for malignancy grade in SPTP have not been well established.The prognosis of SPTP is generally good,with cases having a chance for long-term survival even with recurrence and/or metastasis after surgical resection.The current American Joint Committee on Cancer/Union for International Cancer Control tumor,node,metastasis staging system is not specific to SPTP.The lack of a pre-dictive staging classification that accurately describes the heterogeneity of this disease hinders meaningful research into optimal individualized therapy.Here we summarize and discuss the associated factors proposed for appraisal of the malignant potential and adverse outcome of SPTP.展开更多
Searching for free-standing and cost-efficient hydrogen evolution reaction(HER)electrocatalysts with high efficiency and excellent durability remains a great challenge for the hydrogen-based energy industry.Here,we re...Searching for free-standing and cost-efficient hydrogen evolution reaction(HER)electrocatalysts with high efficiency and excellent durability remains a great challenge for the hydrogen-based energy industry.Here,we report fabrication of a unique hierarchically porous structure,i.e.,nanoporous Ni(NPN)/metallic glass(MG)composite,through surface dealloying of the specially designed Ni_(40)Zr_(40)Ti_(20)MG wire.This porous composite is composed of micrometer slits staggered with nanometer pores,which not only enlarges effective surface areas for the catalytic reaction,but also facilitates the release of H2 gas.As a result,the NPN/MG hybrid electrode exhibited the prominent HER performance with a low overpotential of 78 m V at 10 m A cm^(-2)and Tafel slope of 42.4 m V dec^(-1),along with outstanding stability in alkaline solutions.Outstanding catalytic properties,combining with their free-standing capability and cost efficiency,make the current composite electrode viable for HER applications.展开更多
OBJECTIVE： To provide existence of abnormal potential evidence for the Savda, we assessed host metabonomic responses and dynamic changes oc- curring in various diseases using 1H nuclear mag- netic resonance （NMR）-b...OBJECTIVE： To provide existence of abnormal potential evidence for the Savda, we assessed host metabonomic responses and dynamic changes oc- curring in various diseases using 1H nuclear mag- netic resonance （NMR）-based metabonomics. METHODS： Plasma samples taken from patients with complicated diseases with abnormal Savda （n= 140, including 35 cases each of diabetes, asthma, breast cancer, and cervical carcinoma） and from healthy controls （n=35） were analyzed by ~H NMR （600 MHz）, and the spectral profiles were analyzed by multivariate analysis using orthogonal projec- tion to latent structure with discriminant analysis. RESULTS： Supervised modeling of the data provid- ed very good discrimination between patients and healthy controls. Compared with ,the healthy controls, the patient groups with different disease con- ditions displayed similar metabolic changes, characterized by lower creatine, creatinine, lactate, and amino acid levels （including isoleucine, leucine, va- line, alanine, and 1-methylhistidine） and higher lip- id levels （very low-density lipoproteins and unsatu- rated lipids）. Additionally, cancer patients （breast and cervical） showed decreased myo-inositol, a-glucose, and 13-glucose, and increased pyruvate and carnitine in plasma. CONCLUSION： The data indicate that decreased ox- idative defense, liver function abnormalities, amino acid deficiencies, and energy metabolism disorders are common characteristics of complicated diseas- es, which may be related to the formation of abnor- mal Savda.展开更多
To provide global service with low latency, the broadband low earth orbits (LEO) satellite constellation based communication systems have become one of the focuses in academic and industry. To allow for wideband acces...To provide global service with low latency, the broadband low earth orbits (LEO) satellite constellation based communication systems have become one of the focuses in academic and industry. To allow for wideband access for user links, the feeder link of LEO satellite is correspondingly required to support high throughput data communications. To this end, we propose to apply line-of-sight (LoS) multiple-input multiple-output (MIMO) transmission for the feeder link to achieve spatial multiplexing by optimizing the antenna arrangement. Unlike the LoS MIMO applications for static scenarios, the movement of LEO satellites make it impractical to adjust the optimal antenna separation for all possible satellite positions. To address this issue, we propose to design the antenna placement to maximize the ergodic channel capacity during the visible region of the ground station. We first derive the closed-form probability distribution of the satellite trajectory in visible region. Based on which the ergodic channel capacity can be then calculated numerically. The antenna placement can be further optimized to maximize the ergodic channel capacity. Numerical results verify the derived probability distribution of the satellite trajectory, and show that the proposed LoS MIMO scheme can significantly increase the ergodic channel capacity compared with the existing SISO one.展开更多
Target maneuver trajectory prediction is an important prerequisite for air combat situation awareness and maneuver decision-making.However,how to use a large amount of trajectory data generated by air combat confronta...Target maneuver trajectory prediction is an important prerequisite for air combat situation awareness and maneuver decision-making.However,how to use a large amount of trajectory data generated by air combat confrontation training to achieve real-time and accurate prediction of target maneuver trajectory is an urgent problem to be solved.To solve this problem,in this paper,a hybrid algorithm based on transfer learning,online learning,ensemble learning,regularization technology,target maneuvering segmentation point recognition algorithm,and Volterra series,abbreviated as AERTrOS-Volterra is proposed.Firstly,the model makes full use of a large number of trajectory sample data generated by air combat confrontation training,and constructs a Tr-Volterra algorithm framework suitable for air combat target maneuver trajectory prediction,which realizes the extraction of effective information from the historical trajectory data.Secondly,in order to improve the real-time online prediction accuracy and robustness of the prediction model in complex electromagnetic environments,on the basis of the TrVolterra algorithm framework,a robust regularized online Sequential Volterra prediction model is proposed by integrating online learning method,regularization technology and inverse weighting calculation method based on the priori error.Finally,inspired by the preferable performance of models ensemble,ensemble learning scheme is also incorporated into our proposed algorithm,which adaptively updates the ensemble prediction model according to the performance of the model on real-time samples and the recognition results of target maneuvering segmentation points,including the adaptation of model weights;adaptation of parameters;and dynamic inclusion and removal of models.Compared with many existing time series prediction methods,the newly proposed target maneuver trajectory prediction algorithm can fully mine the prior knowledge contained in the historical data to assist the current prediction.The rationality and effectiveness of the proposed algorithm are verified by simulation on three sets of chaotic time series data sets and a set of real target maneuver trajectory data sets.展开更多
BACKGROUND Total pancreatectomy (TP) is usually considered a therapeutic option forpancreatic cancer in which Whipple surgery and distal pancreatectomy areundesirable, but brittle diabetes and poor quality of life (Qo...BACKGROUND Total pancreatectomy (TP) is usually considered a therapeutic option forpancreatic cancer in which Whipple surgery and distal pancreatectomy areundesirable, but brittle diabetes and poor quality of life (QoL) remain majorconcerns. A subset of patients who underwent TP even died due to severehypoglycemia. For pancreatic cancer involving the pancreatic head and proximalbody but without invasion to the pancreatic tail, we performed partial pancreatictail preserving subtotal pancreatectomy (PPTP-SP) in selected patients, in order toimprove postoperative glycemic control and QoL without compromisingoncological outcomes.AIM To evaluate the efficacy of PPTP-SP for patients with pancreatic cancer.METHODS We retrospectively reviewed 56 patients with pancreatic ductal adenocarcinomawho underwent PPTP-SP (n = 18) or TP (n = 38) at our institution from May 2014to January 2019. Clinical outcomes were compared between the two groups, withan emphasis on oncological outcomes, postoperative glycemic control, and QoL.QoL was evaluated using the European Organization for Research and Treatmentof Cancer Quality of Life Questionnaire (EORTC QLQ-C30 and EORTC PAN26).All patients were followed until May 2019 or until death.RESULTS A total of 56 consecutive patients were enrolled in this study. Perioperativeoutcomes, recurrence-free survival, and overall survival were comparablebetween the two groups. No patients in the PPTP-SP group developed cancerrecurrence in the pancreatic tail stump or splenic hilum, or a clinical pancreaticfistula. Patients who underwent PPTP-SP had significantly better glycemiccontrol, based on their higher rate of insulin-independence (P = 0.014), lowerhemoglobin A1c (HbA1c) level (P = 0.046), lower daily insulin dosage (P < 0.001),and less frequent hypoglycemic episodes (P < 0.001). Global health was similar inthe two groups, but patients who underwent PPTP-SP had better functional status(P = 0.036), milder symptoms (P = 0.013), less severe diet restriction (P = 0.011),and higher confidence regarding future life (P = 0.035).CONCLUSION For pancreatic cancer involving the pancreatic head and proximal body, PPTP-SPachieves perioperative and oncological outcomes comparable to TP in selectedpatients while significantly improving long-term glycemic control and QoL.展开更多
We report the creation of the first mixture of ^6Li and ^88Sr atoms in an optical dipole trap. Using this mixture,a measurement of the interspecies thermalization process is carried out and the previously unknown inte...We report the creation of the first mixture of ^6Li and ^88Sr atoms in an optical dipole trap. Using this mixture,a measurement of the interspecies thermalization process is carried out and the previously unknown interspecies s-wave scattering length between ^6Li and ^88Sr atoms is extracted to be |a6 Li-88 Sr|=(380-100^+160)a0 with a0 being the Bohr radius from the rate of interspecies thermalization.展开更多
Dynamical decoupling(DD)is normally ineffective when applied to DC measurement.In its straightforward implementation,DD nulls out DC signal as well while suppressing noise.This work proposes a phase relay method that ...Dynamical decoupling(DD)is normally ineffective when applied to DC measurement.In its straightforward implementation,DD nulls out DC signal as well while suppressing noise.This work proposes a phase relay method that is capable of continuously interrogating the DC signal over many DD cycles.We illustrate its efficacy when applied to the measurement of a weak DC magnetic field with an atomic spinor Bose-Einstein condensate.Sensitivities approaching standard quantum limit or Heisenberg limit are potentially realizable for a coherent spin state or a squeezed spin state of 10000 atoms,respectively,while ambient laboratory level noise is suppressed by DD.Our work offers a practical approach to mitigate the limitations of DD to DC measurement and would find other applications for resorting coherence in quantum sensing and quantum information processing research.展开更多
This paper investigates the low earth orbit(LEO)satellite-enabled coded compressed sensing(CCS)unsourced random access(URA)in orthogonal frequency division multiple access(OFDMA)framework,where a massive uniform plana...This paper investigates the low earth orbit(LEO)satellite-enabled coded compressed sensing(CCS)unsourced random access(URA)in orthogonal frequency division multiple access(OFDMA)framework,where a massive uniform planar array(UPA)is equipped on the satellite.In LEO satellite communications,unavoidable timing and frequency offsets cause phase shifts in the transmitted signals,substantially diminishing the decoding performance of current terrestrial CCS URA receiver.To cope with this issue,we expand the inner codebook with predefined timing and frequency offsets and formulate the inner decoding as a tractable compressed sensing(CS)problem.Additionally,we leverage the inherent sparsity of the UPA-equipped LEO satellite angular domain channels,thereby enabling the outer decoder to support more active devices.Furthermore,the outputs of the outer decoder are used to reduce the search space of the inner decoder,which cuts down the computational complexity and accelerates the convergence of the inner decoding.Simulation results verify the effectiveness of the proposed scheme.展开更多
A finite time controller with PD-like structure for satellite attitude control is proposed in this paper.The controller is constructed with simple structure based on standard PD controller.The fractional order term is...A finite time controller with PD-like structure for satellite attitude control is proposed in this paper.The controller is constructed with simple structure based on standard PD controller.The fractional order term is designed hence system could both have strong robustness and finite time convergence rate,and the advantage of finite time control and PD control is combined in this paper.System convergence rate is discussed by Lyapunov method,and the constraint on control parameters is given by implementing the coupled term of angular velocity and attitude quaternion.Moreover,the accuracy at steady stage depending on control parameters is given hence system could converge to this field within finite time.System stability and performance is demonstrated by numerical simulation results.展开更多
In our previous report[Chin.Phys.Lett.36(2019)073401],the angular trap frequencies cji and 5 in Eq.(2)were wrongly substituted with trap frequencies(without 2π)at the computation stage.This results in underestimation...In our previous report[Chin.Phys.Lett.36(2019)073401],the angular trap frequencies cji and 5 in Eq.(2)were wrongly substituted with trap frequencies(without 2π)at the computation stage.This results in underestimation of the atom densities and thereby overestimation of the s-wave scatteting length between 6Li and 88Sr atoms.展开更多
Based on core and casting slice observation, well drilling and logging data, the source of carbonate materials, lithology together with electric properties, types, genesis mechanism and distribution of calcareous inte...Based on core and casting slice observation, well drilling and logging data, the source of carbonate materials, lithology together with electric properties, types, genesis mechanism and distribution of calcareous interbeds in Songtao uplift and its periphery of Qiongdongnan Basin have been thoroughly analyzed. Results show that typical features have been appeared from well logging curves, containing low gamma-ray, low acoustic travel time, low neutron value, high density, as well as bright white calcium nodules or bands in electrical imaging well-logging curves. Drilling results reveal that calcareous interbeds developed mostly in high position of paleostructures and their distribution was controlled by the combined effects of macroscopic and microscopic factors. Macroscopically, calcareous interbeds relate to paleogeomorphology together with the combination of sandstone and mudstone. They are also controlled microscopically by the source of carbonate cements and pore space. Under normal circumstances, with regard to the same sand, the closer to the mudstone and the thicker of mudstone, the more conducive to the formation of calcareous interlayer. Low compaction strength, high content of rigid particles, coarse grain size, well-sorted sandstone and large pore space during carbonate cementation are favorable for the development of calcareous interbeds.展开更多
文摘Since solid pseudopapillary tumor of the pancreas(SP-TP) was officially classified by the World Health Org-anization in 1996,SPTP has recently received special attention in the literature.Studies have shown that SPTP is a heterogeneous tumor,with a small percentage of patients harboring aggressive behaviors.However,cri-teria for malignancy grade in SPTP have not been well established.The prognosis of SPTP is generally good,with cases having a chance for long-term survival even with recurrence and/or metastasis after surgical resection.The current American Joint Committee on Cancer/Union for International Cancer Control tumor,node,metastasis staging system is not specific to SPTP.The lack of a pre-dictive staging classification that accurately describes the heterogeneity of this disease hinders meaningful research into optimal individualized therapy.Here we summarize and discuss the associated factors proposed for appraisal of the malignant potential and adverse outcome of SPTP.
基金supported by National Natural Science Foundation of China(Nos.11790293,51871016,51671018,51671021,and 51961160729)the Funds for Creative Research Groups of China(No.51921001)+3 种基金111 Project(B07003)the Program for Changjiang Scholars and Innovative Research Team in University of China(IRT 14R05)the Fundamental Research Funds for the Central Universities(Nos.FRF-GF-19-011A,FRF-TP-18-004C1,FRF-BD-19-002B,and FRF-TP19-054A2)partially supported by State Key Laboratory for Advanced Metals and Materials(2018Z-19)。
文摘Searching for free-standing and cost-efficient hydrogen evolution reaction(HER)electrocatalysts with high efficiency and excellent durability remains a great challenge for the hydrogen-based energy industry.Here,we report fabrication of a unique hierarchically porous structure,i.e.,nanoporous Ni(NPN)/metallic glass(MG)composite,through surface dealloying of the specially designed Ni_(40)Zr_(40)Ti_(20)MG wire.This porous composite is composed of micrometer slits staggered with nanometer pores,which not only enlarges effective surface areas for the catalytic reaction,but also facilitates the release of H2 gas.As a result,the NPN/MG hybrid electrode exhibited the prominent HER performance with a low overpotential of 78 m V at 10 m A cm^(-2)and Tafel slope of 42.4 m V dec^(-1),along with outstanding stability in alkaline solutions.Outstanding catalytic properties,combining with their free-standing capability and cost efficiency,make the current composite electrode viable for HER applications.
基金Supported by China National Natural Science Foundation Program (No.81160459)
文摘OBJECTIVE： To provide existence of abnormal potential evidence for the Savda, we assessed host metabonomic responses and dynamic changes oc- curring in various diseases using 1H nuclear mag- netic resonance （NMR）-based metabonomics. METHODS： Plasma samples taken from patients with complicated diseases with abnormal Savda （n= 140, including 35 cases each of diabetes, asthma, breast cancer, and cervical carcinoma） and from healthy controls （n=35） were analyzed by ~H NMR （600 MHz）, and the spectral profiles were analyzed by multivariate analysis using orthogonal projec- tion to latent structure with discriminant analysis. RESULTS： Supervised modeling of the data provid- ed very good discrimination between patients and healthy controls. Compared with ,the healthy controls, the patient groups with different disease con- ditions displayed similar metabolic changes, characterized by lower creatine, creatinine, lactate, and amino acid levels （including isoleucine, leucine, va- line, alanine, and 1-methylhistidine） and higher lip- id levels （very low-density lipoproteins and unsatu- rated lipids）. Additionally, cancer patients （breast and cervical） showed decreased myo-inositol, a-glucose, and 13-glucose, and increased pyruvate and carnitine in plasma. CONCLUSION： The data indicate that decreased ox- idative defense, liver function abnormalities, amino acid deficiencies, and energy metabolism disorders are common characteristics of complicated diseas- es, which may be related to the formation of abnor- mal Savda.
基金supported by the National Key R&D Program of China under Grant 2019YFB1803102
文摘To provide global service with low latency, the broadband low earth orbits (LEO) satellite constellation based communication systems have become one of the focuses in academic and industry. To allow for wideband access for user links, the feeder link of LEO satellite is correspondingly required to support high throughput data communications. To this end, we propose to apply line-of-sight (LoS) multiple-input multiple-output (MIMO) transmission for the feeder link to achieve spatial multiplexing by optimizing the antenna arrangement. Unlike the LoS MIMO applications for static scenarios, the movement of LEO satellites make it impractical to adjust the optimal antenna separation for all possible satellite positions. To address this issue, we propose to design the antenna placement to maximize the ergodic channel capacity during the visible region of the ground station. We first derive the closed-form probability distribution of the satellite trajectory in visible region. Based on which the ergodic channel capacity can be then calculated numerically. The antenna placement can be further optimized to maximize the ergodic channel capacity. Numerical results verify the derived probability distribution of the satellite trajectory, and show that the proposed LoS MIMO scheme can significantly increase the ergodic channel capacity compared with the existing SISO one.
基金the support of the Fundamental Research Funds for the Air Force Engineering University under Grant No.XZJK2019040。
文摘Target maneuver trajectory prediction is an important prerequisite for air combat situation awareness and maneuver decision-making.However,how to use a large amount of trajectory data generated by air combat confrontation training to achieve real-time and accurate prediction of target maneuver trajectory is an urgent problem to be solved.To solve this problem,in this paper,a hybrid algorithm based on transfer learning,online learning,ensemble learning,regularization technology,target maneuvering segmentation point recognition algorithm,and Volterra series,abbreviated as AERTrOS-Volterra is proposed.Firstly,the model makes full use of a large number of trajectory sample data generated by air combat confrontation training,and constructs a Tr-Volterra algorithm framework suitable for air combat target maneuver trajectory prediction,which realizes the extraction of effective information from the historical trajectory data.Secondly,in order to improve the real-time online prediction accuracy and robustness of the prediction model in complex electromagnetic environments,on the basis of the TrVolterra algorithm framework,a robust regularized online Sequential Volterra prediction model is proposed by integrating online learning method,regularization technology and inverse weighting calculation method based on the priori error.Finally,inspired by the preferable performance of models ensemble,ensemble learning scheme is also incorporated into our proposed algorithm,which adaptively updates the ensemble prediction model according to the performance of the model on real-time samples and the recognition results of target maneuvering segmentation points,including the adaptation of model weights;adaptation of parameters;and dynamic inclusion and removal of models.Compared with many existing time series prediction methods,the newly proposed target maneuver trajectory prediction algorithm can fully mine the prior knowledge contained in the historical data to assist the current prediction.The rationality and effectiveness of the proposed algorithm are verified by simulation on three sets of chaotic time series data sets and a set of real target maneuver trajectory data sets.
基金We thank Professor Yang F and Dr. Shi HJ for their contribution to manuscriptrevision, Yan D and Lee E for further linguistic revision, and Zhang L for diagramdrawing.
文摘BACKGROUND Total pancreatectomy (TP) is usually considered a therapeutic option forpancreatic cancer in which Whipple surgery and distal pancreatectomy areundesirable, but brittle diabetes and poor quality of life (QoL) remain majorconcerns. A subset of patients who underwent TP even died due to severehypoglycemia. For pancreatic cancer involving the pancreatic head and proximalbody but without invasion to the pancreatic tail, we performed partial pancreatictail preserving subtotal pancreatectomy (PPTP-SP) in selected patients, in order toimprove postoperative glycemic control and QoL without compromisingoncological outcomes.AIM To evaluate the efficacy of PPTP-SP for patients with pancreatic cancer.METHODS We retrospectively reviewed 56 patients with pancreatic ductal adenocarcinomawho underwent PPTP-SP (n = 18) or TP (n = 38) at our institution from May 2014to January 2019. Clinical outcomes were compared between the two groups, withan emphasis on oncological outcomes, postoperative glycemic control, and QoL.QoL was evaluated using the European Organization for Research and Treatmentof Cancer Quality of Life Questionnaire (EORTC QLQ-C30 and EORTC PAN26).All patients were followed until May 2019 or until death.RESULTS A total of 56 consecutive patients were enrolled in this study. Perioperativeoutcomes, recurrence-free survival, and overall survival were comparablebetween the two groups. No patients in the PPTP-SP group developed cancerrecurrence in the pancreatic tail stump or splenic hilum, or a clinical pancreaticfistula. Patients who underwent PPTP-SP had significantly better glycemiccontrol, based on their higher rate of insulin-independence (P = 0.014), lowerhemoglobin A1c (HbA1c) level (P = 0.046), lower daily insulin dosage (P < 0.001),and less frequent hypoglycemic episodes (P < 0.001). Global health was similar inthe two groups, but patients who underwent PPTP-SP had better functional status(P = 0.036), milder symptoms (P = 0.013), less severe diet restriction (P = 0.011),and higher confidence regarding future life (P = 0.035).CONCLUSION For pancreatic cancer involving the pancreatic head and proximal body, PPTP-SPachieves perioperative and oncological outcomes comparable to TP in selectedpatients while significantly improving long-term glycemic control and QoL.
基金Supported by the National Key Research and Development Program of China under Grant Nos 2018YFA0306503 and 2018YFA0306504the National Natural Science Foundation of China under Grant Nos 91636213,91736311,11574177,91836302 and 11654001
文摘We report the creation of the first mixture of ^6Li and ^88Sr atoms in an optical dipole trap. Using this mixture,a measurement of the interspecies thermalization process is carried out and the previously unknown interspecies s-wave scattering length between ^6Li and ^88Sr atoms is extracted to be |a6 Li-88 Sr|=(380-100^+160)a0 with a0 being the Bohr radius from the rate of interspecies thermalization.
基金Project supported by the NSAF(Grant No.U1930201)the National Natural Science Foundation of China(Grant Nos.12274331,91836101,and 91836302)+1 种基金the National Key R&D Program of China(Grant No.2018YFA0306504)Innovation Program for Quantum Science and Technology(Grant No.2021ZD0302100).
文摘Dynamical decoupling(DD)is normally ineffective when applied to DC measurement.In its straightforward implementation,DD nulls out DC signal as well while suppressing noise.This work proposes a phase relay method that is capable of continuously interrogating the DC signal over many DD cycles.We illustrate its efficacy when applied to the measurement of a weak DC magnetic field with an atomic spinor Bose-Einstein condensate.Sensitivities approaching standard quantum limit or Heisenberg limit are potentially realizable for a coherent spin state or a squeezed spin state of 10000 atoms,respectively,while ambient laboratory level noise is suppressed by DD.Our work offers a practical approach to mitigate the limitations of DD to DC measurement and would find other applications for resorting coherence in quantum sensing and quantum information processing research.
基金supported by the National Key R&D Program of China under Grant 2023YFB2904703the National Natural Science Foundation of China under Grant 62341110,62371122 and 62322104+1 种基金the Jiangsu Province Basic Research Project under Grant BK20192002the Fundamental Research Funds for the Central Universities under Grant 2242022k30005 and 2242023K5003。
文摘This paper investigates the low earth orbit(LEO)satellite-enabled coded compressed sensing(CCS)unsourced random access(URA)in orthogonal frequency division multiple access(OFDMA)framework,where a massive uniform planar array(UPA)is equipped on the satellite.In LEO satellite communications,unavoidable timing and frequency offsets cause phase shifts in the transmitted signals,substantially diminishing the decoding performance of current terrestrial CCS URA receiver.To cope with this issue,we expand the inner codebook with predefined timing and frequency offsets and formulate the inner decoding as a tractable compressed sensing(CS)problem.Additionally,we leverage the inherent sparsity of the UPA-equipped LEO satellite angular domain channels,thereby enabling the outer decoder to support more active devices.Furthermore,the outputs of the outer decoder are used to reduce the search space of the inner decoder,which cuts down the computational complexity and accelerates the convergence of the inner decoding.Simulation results verify the effectiveness of the proposed scheme.
基金supported partially by National Natural Science Foundation of China(Project Nos.61903289 and 62073102)。
文摘A finite time controller with PD-like structure for satellite attitude control is proposed in this paper.The controller is constructed with simple structure based on standard PD controller.The fractional order term is designed hence system could both have strong robustness and finite time convergence rate,and the advantage of finite time control and PD control is combined in this paper.System convergence rate is discussed by Lyapunov method,and the constraint on control parameters is given by implementing the coupled term of angular velocity and attitude quaternion.Moreover,the accuracy at steady stage depending on control parameters is given hence system could converge to this field within finite time.System stability and performance is demonstrated by numerical simulation results.
文摘In our previous report[Chin.Phys.Lett.36(2019)073401],the angular trap frequencies cji and 5 in Eq.(2)were wrongly substituted with trap frequencies(without 2π)at the computation stage.This results in underestimation of the atom densities and thereby overestimation of the s-wave scatteting length between 6Li and 88Sr atoms.
文摘Based on core and casting slice observation, well drilling and logging data, the source of carbonate materials, lithology together with electric properties, types, genesis mechanism and distribution of calcareous interbeds in Songtao uplift and its periphery of Qiongdongnan Basin have been thoroughly analyzed. Results show that typical features have been appeared from well logging curves, containing low gamma-ray, low acoustic travel time, low neutron value, high density, as well as bright white calcium nodules or bands in electrical imaging well-logging curves. Drilling results reveal that calcareous interbeds developed mostly in high position of paleostructures and their distribution was controlled by the combined effects of macroscopic and microscopic factors. Macroscopically, calcareous interbeds relate to paleogeomorphology together with the combination of sandstone and mudstone. They are also controlled microscopically by the source of carbonate cements and pore space. Under normal circumstances, with regard to the same sand, the closer to the mudstone and the thicker of mudstone, the more conducive to the formation of calcareous interlayer. Low compaction strength, high content of rigid particles, coarse grain size, well-sorted sandstone and large pore space during carbonate cementation are favorable for the development of calcareous interbeds.
