Nodal line semimetal(NLS) is a new quantum state hosting one-dimensional closed loops formed by the crossing of two bands. The so-called type-Ⅱ NLS means that these two crossing bands have the same sign in their slop...Nodal line semimetal(NLS) is a new quantum state hosting one-dimensional closed loops formed by the crossing of two bands. The so-called type-Ⅱ NLS means that these two crossing bands have the same sign in their slopes along the radial direction of the loop, which requires that the crossing bands are either right-tilted or left-tilted at the same time. According to the theoretical prediction, Mg3Bi2 is an ideal candidate for studying the type-Ⅱ NLS by tuning its spin-orbit coupling(SOC). High-quality Mg3 Bi2 films are grown by molecular beam epitaxy(MBE). By in-situ angle resolved photoemission spectroscopy(ARPES), a pair of surface resonance bands around theГ point are clearly seen. This shows that Mg3Bi2 films grown by MBE are Mg(1)-terminated by comparing the ARPES spectra with the first principles calculations results. Moreover, the temperature dependent weak anti-localization effect in Mg3Bi2 films is observed under magneto-transport measurements, which shows clear two-dimensional(2 D) e-e scattering characteristics by fitting with the Hikami–Larkin–Nagaoka model. Therefore, by combining with ARPES, magneto-transport measurements and the first principles calculations, this work proves that Mg3Bi2 is a semimetal with topological surface states. This paves the way for Mg3Bi2 to be used as an ideal material platform to study the exotic features of type-Ⅱ nodal line semimetals and the topological phase transition by tuning its SOC.展开更多
Essential language sites and the arcuate fasciculus（AF） have been extensively researched. However, the relationship between them remains insufficiently studied,especially in healthy people. Navigated transcranial ma...Essential language sites and the arcuate fasciculus（AF） have been extensively researched. However, the relationship between them remains insufficiently studied,especially in healthy people. Navigated transcranial magnetic stimulation（n TMS） is increasingly used in language mapping. While enjoying the advantage of non-invasiveness, it is also capable of inducing a virtual lesion in the brain. Thus, it offers the possibility of using the virtuallesion method to study the healthy brain. This study combined n TMS and diffusion tensor imaging（DTI）tractography to investigate the relationship between essential language sites and the AF in 30 healthy right-handedvolunteers. A total of 143 essential language sites were identified using n TMS, and a total of 175 AF terminations were identified using DTI tractography. Sixty-six sites had a direct correlation with the AF, accounting for 46% of the total essential language sites. Forty-seven AF terminations harbored essential language sites, accounting for 27% of the total AF terminations. Upon data rendering to the cortical parcellation system, a region-related heterogeneity of the correlation rate was found. This study provides the first data on the relationship between essential language sites and the AF in healthy adults.展开更多
We experimentally engineer a high-spectral-purity single-photon source using a single-interferometer-coupled silicon microring. By the reconfiguration of the interferometer, different coupling conditions can be obtain...We experimentally engineer a high-spectral-purity single-photon source using a single-interferometer-coupled silicon microring. By the reconfiguration of the interferometer, different coupling conditions can be obtained, corresponding to different quality factors for the pump and signal/idler. The ratio between the quality factor of the pump and signal/idler ranges from 0.29 to 2.57. By constructing the signal–idler joint spectral intensity, we intuitively demonstrate the spectral correlation of the signal and idler. As the ratio between the quality factor of the pump and signal/idler increases, the spectral correlation of the signal and idler decreases, i.e., the spectral purity of the signal/idler photons increases. Furthermore,time-integrated second-order correlation of the signal photons is measured, giving a value up to 94.95 ± 3.46%. Such high-spectral-purity photons will improve the visibility of quantum interference and facilitate the development of on-chip quantum information processing.展开更多
The seeds of tested Angelica sinensis （Oliy.）Diels were purchased from the planting base of Hebsi Anguo Traditional Chinese Medicine Market. With the root tips of germinated Angelica sinensis seeds treated with GA3...The seeds of tested Angelica sinensis （Oliy.）Diels were purchased from the planting base of Hebsi Anguo Traditional Chinese Medicine Market. With the root tips of germinated Angelica sinensis seeds treated with GA3 as materials, karyotype analysis was performed by photomicrographic technology and conventional chromosome preparation method. The results showed that the chromosome number of A. sinensis was 2 n=2.2, which accords with previous studies; and no satellites were observed, and the chromosome karyotype was 2A, with the asymmetrical karyotype coefficient （AS.K%） of 54：85%. The total length of the chromosomes was 113.4 pro, and total volume of chromosomes was 83.21 μm3.展开更多
Compared with other stream applications, scientific stream programs are usually bound by memory accesses. Reusing streams across different iterations, i.e. loop-carried stream reuse, can effectively improve the SRF lo...Compared with other stream applications, scientific stream programs are usually bound by memory accesses. Reusing streams across different iterations, i.e. loop-carried stream reuse, can effectively improve the SRF locality, thus reducing memory accesses greatly. In the paper, we first present the algorism identifying loop-carried stream reuse and that exploiting the reuse after analyzing scientific computing applications. We then perform several representative microbenchmarks and scientific stream programs with and without our optimization on Isim, a cycle-accurate stream processor simulator. Experimental results show that our algorithms can effectively exploit loop-carried stream reuse for scientific stream programs and thus greatly improve the performance of memory-bound scientific stream programs.展开更多
To achieve efficient and refined thermal environment simulations for single-phase and two-phase flows in aircraft cabins,we propose an integrated analysis method.This approach enables rapid coupled heat transfer calcu...To achieve efficient and refined thermal environment simulations for single-phase and two-phase flows in aircraft cabins,we propose an integrated analysis method.This approach enables rapid coupled heat transfer calculations among single-phase flow,two-phase flow,and solids within a single time step.For single-phase fluid and solid equipment,a fast numerical algorithm for natural convection is developed using a loosely coupled strategy,dividing the single-phase flow into developmental stages for efficient temperature field computation.For two-phase flow and the fuel tank wall,a transient heat transfer model is constructed at the gas-liquid-solid boundary,facilitating fast thermal analysis.These methods are unified for integrated simulation of the cabin’s thermal environment.Validation based on two-dimensional models demonstrates a speedup by a factor of 7.9,while maintaining an average temperature error of less than 1%at two-phase nodes.The method’s robustness is confirmed under various high-temperature boundary conditions.展开更多
Dear Editor,Diffuse midline glioma,H3K27-altered(DMG),is a pediatric-type high-grade diffuse glioma that preferentially localizes to the brainstem or pons,thalamus,and spinal cord.Surgical resection is challenging and...Dear Editor,Diffuse midline glioma,H3K27-altered(DMG),is a pediatric-type high-grade diffuse glioma that preferentially localizes to the brainstem or pons,thalamus,and spinal cord.Surgical resection is challenging and biopsy is often performed in most cases.To date,no conventional,targeted or immune therapy has been convincingly shown to improve patients’overall survival(OS).展开更多
Aims Seed dormancy and the soil seed bank are crucial to plant regeneration strategy,especially in semiarid ecosystems with unpredictable precipi-tation.the aim of this study was to investigate how seed dormancy is co...Aims Seed dormancy and the soil seed bank are crucial to plant regeneration strategy,especially in semiarid ecosystems with unpredictable precipi-tation.the aim of this study was to investigate how seed dormancy is controlled by environmental factors and how it is correlated with the soil seed bank and regeneration of the perennial legume Oxytropis race-mosa,a dominant perennial herb in Mu Us Sandland of semiarid China.Methods Germination and imbibition experiments on fresh intact and scarified seeds of O.racemosa were used to identify physical dormancy(PY)in seeds of this species.Soil seed bank dynamics,timing of seedling emer-gence and the fate of buried seeds in the natural habitat were investigated.Important Findings PY was broken by mechanical scarification or wet heat/ice water cycles but not solely by dry heat or wet heat treatment.the soil seed bank exhibited seasonal changes in the number of seeds,which was highest in September and lowest in July.Seeds buried at different sand depths gradually lost dormancy;20-42%of the seeds remained dormant after 20 months of burial.Dormancy break occurs grad-ually throughout the year.Our results indicate that O.racemosa exhibits hardcoatedness heterogeneity that spreads germination of a seed cohort between seasons and years in the semiarid environ-ment,where the amount of precipitation during the growing season is highly variable.展开更多
Single photons and photon pairs are typically generated by spontaneous parametric down conversion or quantum dots;however,spontaneous four-wave mixing(SFWM)in silicon microring resonators[1]is also an appealing source...Single photons and photon pairs are typically generated by spontaneous parametric down conversion or quantum dots;however,spontaneous four-wave mixing(SFWM)in silicon microring resonators[1]is also an appealing source of entangled photons,offering a strong cavity-enhanced nonlinear interactions while maintaining features,such as compact,simple to fabricate,and allowing for thermal tuning.However,silicon ring-resonators usually suffer from a trade-off between providing a high pair generation rate(PGR)and high extraction efficiency.To achieve high PGR,devices are generally operated with the signal and idler photons in the undercoupling regime and pump photons at the critical coupling point,while high extraction rates require the converted photons to be overcoupled.Therefore,the optimal conditions for achieving maximal output photon pair flux are critical coupling for the pump photons and overcoupling for the converted photons[2,3].展开更多
Boson sampling is a promising candidate for demonstrating quantum supremacy. The validation that involves judging whether a quantum setup outputs photons following the boson sampling model is an essential task in the ...Boson sampling is a promising candidate for demonstrating quantum supremacy. The validation that involves judging whether a quantum setup outputs photons following the boson sampling model is an essential task in the experiments. However, the current validation methods may result in an incorrect conclusion being reached in realistic experiments, in which no ideally identical photons exist. Accordingly, this study proposes a slope-based approach, which is an extended Bayesian validation, to model the degree of photon indistinguishability. Through numerical simulations and performance evaluations, we demonstrate that the proposed approach can correctly validate boson sampling against the distribution of classical particles. In addition to offering a useful approach for validation, our research indicates that physicists should pay more attention to the quality of photon indistinguishability in boson sampling experiments.展开更多
Glioma of the brain is a kind of tumor originating from neuroglial cells.It is the most common primary intracranial tumor,accounting for~30%of all central nervous system tumors and 80% of malignant brain tumors.Glioma...Glioma of the brain is a kind of tumor originating from neuroglial cells.It is the most common primary intracranial tumor,accounting for~30%of all central nervous system tumors and 80% of malignant brain tumors.Glioma is characterized by high disability and recurrence rates.The disease seriously threatens the life of patients,afects their quality of life,and brings a heavy economic and psychological burden to patients,families,and society.With the progression of molecular genetic testing technology and the completion of various clinical trials,the classifcation scheme for glioma is increasingly well established.Diagnosis and treatment regimens,including traditional and new regimens,are becoming increasingly specialized and standardized.The purpose is to develop a clinical diagnosis and treatment guideline for glioma in the Chinese population suitable for Chinese doctors and the general population based on domestic and international glioma research progress.Thus,domestic practitioners in the feld can obtain current information and provide better service to patients with glioma,promoting the development of domestic clinical medicine and basic research on glioma.展开更多
Background: A pituitary tumor is a tumor with a high incidence among brain tumors. Microscopic traditional STT approach with aid of endoscope has a high therapeutic effect and few complications. Methods: The authors r...Background: A pituitary tumor is a tumor with a high incidence among brain tumors. Microscopic traditional STT approach with aid of endoscope has a high therapeutic effect and few complications. Methods: The authors reviewed 146 patients who underwent STT resection of sellar masses between January 1, 2006, and December 31, 2013. From this group, 40 patients who underwent microscopic STT surgery with aid of endoscope were included in the study. In this series, there were many nonfunctional and Growth Hormone(GH) secreting adenoma. In the study group, tumor size ranged from 60 to 79 mm in 3 cases. Pathophysiological studies, tumor sizes, clinical outcomes, extent of resection, visual function and complication were estimated. Results: In our study, gross-total resection(GTR) was achieved in 33 patients (82.5%), subtotal in 3 (7.5%), and partial in 4 (10%). Visual acuity were improved in 82.1%, while 17.9% were unchanged. Visual fields were improved in 81.2%. No deaths occurred in this cohort of patients. Conclusions: Pituitary adenoma surgery under microscope with aid of endoscope is an effective treatment method, which results in high (>90%) rates of resection. It is not associated with high rates of major complications and is safe when performed by experienced surgeons.展开更多
The continuous-time quantum walk is a basic model for studying quantum transport and developing quantum-enhanced algorithms. Recent studies show that by introducing a phase into the standard continuous-time quantum wa...The continuous-time quantum walk is a basic model for studying quantum transport and developing quantum-enhanced algorithms. Recent studies show that by introducing a phase into the standard continuous-time quantum walk model, the time-reversal symmetry can be broken without changing the Hermitian property of the Hamiltonian. The time-reversal symmetry breaking quantum walk shows advantages in quantum transport, such as perfect state transfer, directional control, transport speedup, and quantum transport efficiency enhancement. In this work, we implement the time-reversal symmetry breaking quantum walks on a reconfigurable silicon photonic chip and demonstrate the enhancement introduced by breaking time-reversal symmetry. Perfect state transfer on a three-site ring, a quantum switch implemented on a six-site graph, and transport speedup using a linear chain of triangles are demonstrated with high fidelity. Time-reversal asymmetry has also been used in a simplified light-harvesting model,implying the potential of time-reversal symmetry breaking in photosynthesis investigations.展开更多
Quantum computing is a significant computing capability which is superior to classical computing because of its superposition feature. Distinguishing several quantum states from quantum algorithm outputs is often a vi...Quantum computing is a significant computing capability which is superior to classical computing because of its superposition feature. Distinguishing several quantum states from quantum algorithm outputs is often a vital computational task. In most cases, the quantum states tend to be non-orthogonal due to superposition; quantum mechanics has proved that perfect outcomes could not be achieved by measurements, forcing repetitive measurement. Hence, it is important to determine the optimum measuring method which requires fewer repetitions and a lower error rate. However, extending current measurement approaches mainly aiming at quantum cryptography to multi-qubit situations for quantum computing confronts challenges, such as conducting global operations which has considerable costs in the experimental realm. Therefore, in this study, we have proposed an optimum subsystem method to avoid these difficulties. We have provided an analysis of the comparison between the reduced subsystem method and the global minimum error method for two-qubit problems; the conclusions have been verified experimentally. The results showed that the subsystem method could effectively discriminate non-orthogonal two-qubit states, such as separable states, entangled pure states, and mixed states; the cost of the experimental process had been significantly reduced, in most circumstances, with acceptable error rate. We believe the optimal subsystem method is the most valuable and promising approach for multi-qubit quantum computing applications.展开更多
Background:Pleomorphic xanthoastrocytoma (PXA) is usually considered a relatively benign and localized entity. However, cases of PXA with anaplastic features have been reported in recent years. Anaplastic pleomorphic ...Background:Pleomorphic xanthoastrocytoma (PXA) is usually considered a relatively benign and localized entity. However, cases of PXA with anaplastic features have been reported in recent years. Anaplastic pleomorphic xanthoastrocytoma has been added to the 2016 WHO classification of CNS tumors as a distinct entity. Case presentation:We describe a rare case of PXA with dissemination, both at the time of diagnosis and after treatment. The 20-year-old male presented with signs of high intracranial pressure and sudden-onset transient seizures. Imaging examinations showed diffuse lesions widely distributed in the left hemisphere, and on histopathological examination, he was diagnosed with anaplastic PXA. The patient underwent surgical treatment and adjuvant concurrent chemoradiation. Follow-up MRI revealed early recurrence and distant spread of the tumor. Conclusions:Anaplastic PXA usually has unique characteristics, including dissemination, early recurrence, and chemoresistance. A strategy based on early diagnosis and aggressive treatment is warranted. However, sufficiently powered studies are required to generate evidence-based guidelines.展开更多
基金Supported by the Science Challenge Project under Grant No TZ2016004the Opening Foundation of State Key Laboratory of High Performance Computing under Grant No 201601-02+4 种基金the Foundation of President of CAEP under Grant No 201501040the Natural Science Foundation of Hunan Province under Grant No 2016JJ1021the National Basic Research Program of China under Grant Nos 2015CB921303 and 2012YQ13012508the General Program of Beijing Academy of Quantum Information Sciences under Grant No Y18G17the Youth Talent Lifting Project under Grant No 17-JCJQ-QT-004
文摘Nodal line semimetal(NLS) is a new quantum state hosting one-dimensional closed loops formed by the crossing of two bands. The so-called type-Ⅱ NLS means that these two crossing bands have the same sign in their slopes along the radial direction of the loop, which requires that the crossing bands are either right-tilted or left-tilted at the same time. According to the theoretical prediction, Mg3Bi2 is an ideal candidate for studying the type-Ⅱ NLS by tuning its spin-orbit coupling(SOC). High-quality Mg3 Bi2 films are grown by molecular beam epitaxy(MBE). By in-situ angle resolved photoemission spectroscopy(ARPES), a pair of surface resonance bands around theГ point are clearly seen. This shows that Mg3Bi2 films grown by MBE are Mg(1)-terminated by comparing the ARPES spectra with the first principles calculations results. Moreover, the temperature dependent weak anti-localization effect in Mg3Bi2 films is observed under magneto-transport measurements, which shows clear two-dimensional(2 D) e-e scattering characteristics by fitting with the Hikami–Larkin–Nagaoka model. Therefore, by combining with ARPES, magneto-transport measurements and the first principles calculations, this work proves that Mg3Bi2 is a semimetal with topological surface states. This paves the way for Mg3Bi2 to be used as an ideal material platform to study the exotic features of type-Ⅱ nodal line semimetals and the topological phase transition by tuning its SOC.
基金supported in part by grants from the National Natural Science Foundation of China(81272782 and 81472352)the Chinese Society of Neuro-oncology,Chinese AntiCancer Association(CSNO2014MSD01)Special Funds for Instruments of the National Natural Science Foundation of China(81127003)
文摘Essential language sites and the arcuate fasciculus（AF） have been extensively researched. However, the relationship between them remains insufficiently studied,especially in healthy people. Navigated transcranial magnetic stimulation（n TMS） is increasingly used in language mapping. While enjoying the advantage of non-invasiveness, it is also capable of inducing a virtual lesion in the brain. Thus, it offers the possibility of using the virtuallesion method to study the healthy brain. This study combined n TMS and diffusion tensor imaging（DTI）tractography to investigate the relationship between essential language sites and the AF in 30 healthy right-handedvolunteers. A total of 143 essential language sites were identified using n TMS, and a total of 175 AF terminations were identified using DTI tractography. Sixty-six sites had a direct correlation with the AF, accounting for 46% of the total essential language sites. Forty-seven AF terminations harbored essential language sites, accounting for 27% of the total AF terminations. Upon data rendering to the cortical parcellation system, a region-related heterogeneity of the correlation rate was found. This study provides the first data on the relationship between essential language sites and the AF in healthy adults.
基金Project supported by the National Basic Research Program of China (Grant Nos. 2019YFA0308700 and 2017YFA0303700)the Open Funds from the State Key Laboratory of High Performance Computing of China (HPCL, National University of Defense Technology)。
文摘We experimentally engineer a high-spectral-purity single-photon source using a single-interferometer-coupled silicon microring. By the reconfiguration of the interferometer, different coupling conditions can be obtained, corresponding to different quality factors for the pump and signal/idler. The ratio between the quality factor of the pump and signal/idler ranges from 0.29 to 2.57. By constructing the signal–idler joint spectral intensity, we intuitively demonstrate the spectral correlation of the signal and idler. As the ratio between the quality factor of the pump and signal/idler increases, the spectral correlation of the signal and idler decreases, i.e., the spectral purity of the signal/idler photons increases. Furthermore,time-integrated second-order correlation of the signal photons is measured, giving a value up to 94.95 ± 3.46%. Such high-spectral-purity photons will improve the visibility of quantum interference and facilitate the development of on-chip quantum information processing.
基金Supported by Tianjin Municipal Science and Technology Project(16KPXMSF00160,16PTZSTG00020)~~
文摘The seeds of tested Angelica sinensis （Oliy.）Diels were purchased from the planting base of Hebsi Anguo Traditional Chinese Medicine Market. With the root tips of germinated Angelica sinensis seeds treated with GA3 as materials, karyotype analysis was performed by photomicrographic technology and conventional chromosome preparation method. The results showed that the chromosome number of A. sinensis was 2 n=2.2, which accords with previous studies; and no satellites were observed, and the chromosome karyotype was 2A, with the asymmetrical karyotype coefficient （AS.K%） of 54：85%. The total length of the chromosomes was 113.4 pro, and total volume of chromosomes was 83.21 μm3.
文摘Compared with other stream applications, scientific stream programs are usually bound by memory accesses. Reusing streams across different iterations, i.e. loop-carried stream reuse, can effectively improve the SRF locality, thus reducing memory accesses greatly. In the paper, we first present the algorism identifying loop-carried stream reuse and that exploiting the reuse after analyzing scientific computing applications. We then perform several representative microbenchmarks and scientific stream programs with and without our optimization on Isim, a cycle-accurate stream processor simulator. Experimental results show that our algorithms can effectively exploit loop-carried stream reuse for scientific stream programs and thus greatly improve the performance of memory-bound scientific stream programs.
文摘To achieve efficient and refined thermal environment simulations for single-phase and two-phase flows in aircraft cabins,we propose an integrated analysis method.This approach enables rapid coupled heat transfer calculations among single-phase flow,two-phase flow,and solids within a single time step.For single-phase fluid and solid equipment,a fast numerical algorithm for natural convection is developed using a loosely coupled strategy,dividing the single-phase flow into developmental stages for efficient temperature field computation.For two-phase flow and the fuel tank wall,a transient heat transfer model is constructed at the gas-liquid-solid boundary,facilitating fast thermal analysis.These methods are unified for integrated simulation of the cabin’s thermal environment.Validation based on two-dimensional models demonstrates a speedup by a factor of 7.9,while maintaining an average temperature error of less than 1%at two-phase nodes.The method’s robustness is confirmed under various high-temperature boundary conditions.
基金This work was supported by Institute of Biomedicine and Tsinghua-Peking Joint Center for Life Sciences and Clinical Medicine Development Fund of Tsinghua University(10001020510).
文摘Dear Editor,Diffuse midline glioma,H3K27-altered(DMG),is a pediatric-type high-grade diffuse glioma that preferentially localizes to the brainstem or pons,thalamus,and spinal cord.Surgical resection is challenging and biopsy is often performed in most cases.To date,no conventional,targeted or immune therapy has been convincingly shown to improve patients’overall survival(OS).
基金This research was supported by the Key Basic Research and Development Plan of P.R.China(2016YFC050080502)the National Natural Science Foundation of P.R.China(31370705,31570416).
文摘Aims Seed dormancy and the soil seed bank are crucial to plant regeneration strategy,especially in semiarid ecosystems with unpredictable precipi-tation.the aim of this study was to investigate how seed dormancy is controlled by environmental factors and how it is correlated with the soil seed bank and regeneration of the perennial legume Oxytropis race-mosa,a dominant perennial herb in Mu Us Sandland of semiarid China.Methods Germination and imbibition experiments on fresh intact and scarified seeds of O.racemosa were used to identify physical dormancy(PY)in seeds of this species.Soil seed bank dynamics,timing of seedling emer-gence and the fate of buried seeds in the natural habitat were investigated.Important Findings PY was broken by mechanical scarification or wet heat/ice water cycles but not solely by dry heat or wet heat treatment.the soil seed bank exhibited seasonal changes in the number of seeds,which was highest in September and lowest in July.Seeds buried at different sand depths gradually lost dormancy;20-42%of the seeds remained dormant after 20 months of burial.Dormancy break occurs grad-ually throughout the year.Our results indicate that O.racemosa exhibits hardcoatedness heterogeneity that spreads germination of a seed cohort between seasons and years in the semiarid environ-ment,where the amount of precipitation during the growing season is highly variable.
基金supported by the National Key Research and Development Program of China(Grant No.2017YFA0303700)the National Natural Science Foundation of China(Grant Nos.61632021,11627810,11690031,and 11621091)Open Funds from the State Key Laboratory of High Performance Computing of China(HPCL,National University of Defense Technology)
文摘Single photons and photon pairs are typically generated by spontaneous parametric down conversion or quantum dots;however,spontaneous four-wave mixing(SFWM)in silicon microring resonators[1]is also an appealing source of entangled photons,offering a strong cavity-enhanced nonlinear interactions while maintaining features,such as compact,simple to fabricate,and allowing for thermal tuning.However,silicon ring-resonators usually suffer from a trade-off between providing a high pair generation rate(PGR)and high extraction efficiency.To achieve high PGR,devices are generally operated with the signal and idler photons in the undercoupling regime and pump photons at the critical coupling point,while high extraction rates require the converted photons to be overcoupled.Therefore,the optimal conditions for achieving maximal output photon pair flux are critical coupling for the pump photons and overcoupling for the converted photons[2,3].
基金supported by the National Natural Science Foundation of China(Grant No.61632021)。
文摘Boson sampling is a promising candidate for demonstrating quantum supremacy. The validation that involves judging whether a quantum setup outputs photons following the boson sampling model is an essential task in the experiments. However, the current validation methods may result in an incorrect conclusion being reached in realistic experiments, in which no ideally identical photons exist. Accordingly, this study proposes a slope-based approach, which is an extended Bayesian validation, to model the degree of photon indistinguishability. Through numerical simulations and performance evaluations, we demonstrate that the proposed approach can correctly validate boson sampling against the distribution of classical particles. In addition to offering a useful approach for validation, our research indicates that physicists should pay more attention to the quality of photon indistinguishability in boson sampling experiments.
基金supported by China Anti-Cancer Association (CACA).
文摘Glioma of the brain is a kind of tumor originating from neuroglial cells.It is the most common primary intracranial tumor,accounting for~30%of all central nervous system tumors and 80% of malignant brain tumors.Glioma is characterized by high disability and recurrence rates.The disease seriously threatens the life of patients,afects their quality of life,and brings a heavy economic and psychological burden to patients,families,and society.With the progression of molecular genetic testing technology and the completion of various clinical trials,the classifcation scheme for glioma is increasingly well established.Diagnosis and treatment regimens,including traditional and new regimens,are becoming increasingly specialized and standardized.The purpose is to develop a clinical diagnosis and treatment guideline for glioma in the Chinese population suitable for Chinese doctors and the general population based on domestic and international glioma research progress.Thus,domestic practitioners in the feld can obtain current information and provide better service to patients with glioma,promoting the development of domestic clinical medicine and basic research on glioma.
文摘Background: A pituitary tumor is a tumor with a high incidence among brain tumors. Microscopic traditional STT approach with aid of endoscope has a high therapeutic effect and few complications. Methods: The authors reviewed 146 patients who underwent STT resection of sellar masses between January 1, 2006, and December 31, 2013. From this group, 40 patients who underwent microscopic STT surgery with aid of endoscope were included in the study. In this series, there were many nonfunctional and Growth Hormone(GH) secreting adenoma. In the study group, tumor size ranged from 60 to 79 mm in 3 cases. Pathophysiological studies, tumor sizes, clinical outcomes, extent of resection, visual function and complication were estimated. Results: In our study, gross-total resection(GTR) was achieved in 33 patients (82.5%), subtotal in 3 (7.5%), and partial in 4 (10%). Visual acuity were improved in 82.1%, while 17.9% were unchanged. Visual fields were improved in 81.2%. No deaths occurred in this cohort of patients. Conclusions: Pituitary adenoma surgery under microscope with aid of endoscope is an effective treatment method, which results in high (>90%) rates of resection. It is not associated with high rates of major complications and is safe when performed by experienced surgeons.
基金supported by the National Key Research and Development Program of China (Grant Nos. 2019YFA0308700, and 2017YFA0303700)。
文摘The continuous-time quantum walk is a basic model for studying quantum transport and developing quantum-enhanced algorithms. Recent studies show that by introducing a phase into the standard continuous-time quantum walk model, the time-reversal symmetry can be broken without changing the Hermitian property of the Hamiltonian. The time-reversal symmetry breaking quantum walk shows advantages in quantum transport, such as perfect state transfer, directional control, transport speedup, and quantum transport efficiency enhancement. In this work, we implement the time-reversal symmetry breaking quantum walks on a reconfigurable silicon photonic chip and demonstrate the enhancement introduced by breaking time-reversal symmetry. Perfect state transfer on a three-site ring, a quantum switch implemented on a six-site graph, and transport speedup using a linear chain of triangles are demonstrated with high fidelity. Time-reversal asymmetry has also been used in a simplified light-harvesting model,implying the potential of time-reversal symmetry breaking in photosynthesis investigations.
基金supported by the National Natural Science Foundation of China(Grant No.61632021)the Open Fund from the State Key Laboratory of High Performance Computing of China(HPCL)(Grant No.201401-01)
文摘Quantum computing is a significant computing capability which is superior to classical computing because of its superposition feature. Distinguishing several quantum states from quantum algorithm outputs is often a vital computational task. In most cases, the quantum states tend to be non-orthogonal due to superposition; quantum mechanics has proved that perfect outcomes could not be achieved by measurements, forcing repetitive measurement. Hence, it is important to determine the optimum measuring method which requires fewer repetitions and a lower error rate. However, extending current measurement approaches mainly aiming at quantum cryptography to multi-qubit situations for quantum computing confronts challenges, such as conducting global operations which has considerable costs in the experimental realm. Therefore, in this study, we have proposed an optimum subsystem method to avoid these difficulties. We have provided an analysis of the comparison between the reduced subsystem method and the global minimum error method for two-qubit problems; the conclusions have been verified experimentally. The results showed that the subsystem method could effectively discriminate non-orthogonal two-qubit states, such as separable states, entangled pure states, and mixed states; the cost of the experimental process had been significantly reduced, in most circumstances, with acceptable error rate. We believe the optimal subsystem method is the most valuable and promising approach for multi-qubit quantum computing applications.
基金We thank grants from the the National Natural Science Foundation of China，the Specialized Research Fund for the Doctoral Program of Higher Education (no. 20131202110006). Both of the two fundings were based on the comprehensive therapy of glioma
文摘Background:Pleomorphic xanthoastrocytoma (PXA) is usually considered a relatively benign and localized entity. However, cases of PXA with anaplastic features have been reported in recent years. Anaplastic pleomorphic xanthoastrocytoma has been added to the 2016 WHO classification of CNS tumors as a distinct entity. Case presentation:We describe a rare case of PXA with dissemination, both at the time of diagnosis and after treatment. The 20-year-old male presented with signs of high intracranial pressure and sudden-onset transient seizures. Imaging examinations showed diffuse lesions widely distributed in the left hemisphere, and on histopathological examination, he was diagnosed with anaplastic PXA. The patient underwent surgical treatment and adjuvant concurrent chemoradiation. Follow-up MRI revealed early recurrence and distant spread of the tumor. Conclusions:Anaplastic PXA usually has unique characteristics, including dissemination, early recurrence, and chemoresistance. A strategy based on early diagnosis and aggressive treatment is warranted. However, sufficiently powered studies are required to generate evidence-based guidelines.
