Although the use of heterosis in maize breeding has increased crop productivity,the genetic causes underlying heterosis for nitrogen(N) use efficiency(NUE) have been insufficiently investigated.In this study,five N-re...Although the use of heterosis in maize breeding has increased crop productivity,the genetic causes underlying heterosis for nitrogen(N) use efficiency(NUE) have been insufficiently investigated.In this study,five N-response traits and five low-N-tolerance traits were investigated using two inbred line populations(ILs) consisting of recombinant inbred lines(RIL) and advanced backcross(ABL) populations,derived from crossing Ye478 with Wu312.Both populations were crossed with P178 to construct two testcross populations.IL populations,their testcross populations,and the midparent heterosis(MPH)for NUE were investigated.Kernel weight,kernel number,and kernel number per row were sensitive to N level and ILs showed higher N response than did the testcross populations.Based on a highdensity linkage map,138 quantitative trait loci(QTL) were mapped,each explaining 5.6%–38.8% of genetic variation.There were 52,34 and 52 QTL for IL populations,MPH,and testcross populations,respectively.The finding that 7.6% of QTL were common to the ILs and their testcross populations and that 11.7% were common to the MPH and testcross population indicated that heterosis for NUE traits was regulated by non-additive and non-dominant loci.A QTL on chromosome 5 explained 27% of genetic variation in all of the traits and Gln1-3 was identified as a candidate gene for this QTL.Genome-wide prediction of NUE traits in the testcross populations showed 14%–51% accuracy.Our results may be useful for clarifying the genetic basis of heterosis for NUE traits and the candidate gene may be used for genetic improvement of maize NUE.展开更多
Mucormycosis is an uncommon and opportunistic fungal infection with high mortality. Infections may result from ingestion of contaminated food, inhalation of spores into the respiratory tract or inoculation into disrup...Mucormycosis is an uncommon and opportunistic fungal infection with high mortality. Infections may result from ingestion of contaminated food, inhalation of spores into the respiratory tract or inoculation into disruptedskin.^([1])Pulmonarymucormycosis(PM)is the most common clinical type.展开更多
Objective: Emerging evidence indicates that long non-coding RNAs(lnc RNAs) are critical in carcinogenesis and progression of ovarian cancer. This study aimed to explore the functions and molecular mechanisms of plasma...Objective: Emerging evidence indicates that long non-coding RNAs(lnc RNAs) are critical in carcinogenesis and progression of ovarian cancer. This study aimed to explore the functions and molecular mechanisms of plasmacytoma variant translocation I(PVT1) in ovarian cancer Methods: PVT1 and miR-214 were detected by qRT-PCR assays in ovarian cancer tissues and cells. The cell proliferation,migration, and invasion abilities were detected by cell functional experiments, respectively. Western blot assay was performed to detect epithelial-mesenchymal transition(EMT) markers. MiR-214 expression regulated by PVT1 was studied by RNA immunoprecipitation(RIP) and chromatin immunoprecipitation(Ch IP) assays.Results: The expression of PVT1 was up-regulated in ovarian cancer tissues and cell lines. Elevated PVT1 expression was associated with advanced stage and indicated poor prognosis for ovarian cancer patients. The knockdown of PVT1 impaired SKOV3 cell proliferation, migration, and invasion in vitro. The promotion of ovarian cancer progression by PVT1 involved in regulation of the epithelial-mesenchymal transition process and PVT1 interaction with EZH2 represses miR-214 expression in ovarian cancer cells.Conclusions: PVT1 plays an important role in ovarian cancer tumorigenesis, which might be as a novel diagnostic marker and therapeutic target for ovarian cancer.展开更多
A microgrid is hard to control due to its reduced inertia and increased uncertainties. To overcome the challenges of microgrid control, advanced controllers need to be developed.In this paper, a distributed, two-level...A microgrid is hard to control due to its reduced inertia and increased uncertainties. To overcome the challenges of microgrid control, advanced controllers need to be developed.In this paper, a distributed, two-level, communication-economic control scheme is presented for multiple-bus microgrids with each bus having multiple distributed generators(DGs) connected in parallel. The control objective of the upper level is to calculate the voltage references for one-bus subsystems. The objectives of the lower control level are to make the subsystems' bus voltages track the voltage references and to enhance load current sharing accuracy among the local DGs. Firstly, a distributed consensusbased power sharing algorithm is introduced to determine the power generations of the subsystems. Secondly, a discrete-time droop equation is used to adjust subsystem frequencies for voltage reference calculations. Finally, a Lyapunov-based decentralized control algorithm is designed for bus voltage regulation and proportional load current sharing. Extensive simulation studies with microgrid models of different levels of detail are performed to demonstrate the merits of the proposed control scheme.展开更多
This article presents a distributed periodic eventtriggered(PET)optimal control scheme to achieve generation cost minimization and average bus voltage regulation in DC microgrids.In order to accommodate the generation...This article presents a distributed periodic eventtriggered(PET)optimal control scheme to achieve generation cost minimization and average bus voltage regulation in DC microgrids.In order to accommodate the generation constraints of the distributed generators(DGs),a virtual incremental cost is firstly designed,based on which an optimality condition is derived to facilitate the control design.To meet the discrete-time(DT)nature of modern control systems,the optimal controller is directly developed in the DT domain.Afterward,to reduce the communication requirement among the controllers,a distributed event-triggered mechanism is introduced for the DT optimal controller.The event-triggered condition is detected periodically and therefore naturally avoids the Zeno phenomenon.The closed-loop system stability is proved by the Lyapunov synthesis for switched systems.The generation cost minimization and average bus voltage regulation are obtained at the equilibrium point.Finally,switch-level microgrid simulations validate the performance of the proposed optimal controller.展开更多
The large inertia of a traditional power system slows down system's frequency response but also allows decent time for controlling the system.Since an autonomous renewable microgrid usually has much smaller inerti...The large inertia of a traditional power system slows down system's frequency response but also allows decent time for controlling the system.Since an autonomous renewable microgrid usually has much smaller inertia,the control system must be very fast and accurate to fight against the small inertia and uncertainties.To reduce the demanding requirements on control,this paper proposes to increase the inertia of photovoltaic(PV) system through inertia emulation.The inertia emulation is realized by controlling the charging/discharging of the direct current(DC)-link capacitor over a certain range and adjusting the PV generation when it is feasible and/or necessary.By well designing the inertia,the DC-link capacitor parameters and the control range,the negative impact of inertia emulation on energy efficiency can be reduced.The proposed algorithm can be integrated with distributed generation setting algorithms to improve dynamic performance and lower implementation requirements.Simulation studies demonstrate the effectiveness of the proposed solution.展开更多
Genome-wide prediction is a promising approach to boost selection gain in hybrid breeding.Our main objective was to evaluate the potential and limits of genome-wide prediction to identify superior hybrid combinations ...Genome-wide prediction is a promising approach to boost selection gain in hybrid breeding.Our main objective was to evaluate the potential and limits of genome-wide prediction to identify superior hybrid combinations adapted to Northwest China.A total of 490 hybrids derived from crosses among 119 inbred lines from the Shaan A and Shaan B heterotic pattern were used for genome-wide prediction of ten agronomic traits.We tested eight different statistical prediction models considering additive(A)effects and in addition evaluated the impact of dominance(D)and epistasis(E)on the prediction ability.Employing five-fold cross validation,we show that the average prediction ability ranged from 0.386 to 0.794 across traits and models.Six parametric methods,i.e.ridge regression,LASSO,Elastic Net,Bayes B,Bayes C and reproducing kernel Hilbert space(RKHS)approach,displayed a very similar prediction ability for each trait and two non-parametric methods(random forest and support vector machine)had a higher prediction performance for the trait rind penetrometer resistance of the third internode above ground(RPR_TIAG).The models of A+D RKHS and A+D+E RKHS were slightly better for predicting traits with a relatively high non-additive variance.Integrating trait-specific markers into the A+D RKHS model improved the prediction ability of grain yield by 3%,from 0.528 to 0.558.Of all 6328 potential hybrids,selection of the top 44 hybrids would lead to a 6%increase in grain yield compared with Zhengdan 958,a commercially successful hybrid variety.In conclusion,our results substantiate the value of genome-wide prediction for hybrid breeding and suggest dozens of promising single crosses for developing high-yielding hybrids for Northwest China.展开更多
A single-bus DC microgrid can represent a wide range of applications. Control objectives of such systems include high-performance bus voltage regulation and proper load sharing among multiple distributed generators(DG...A single-bus DC microgrid can represent a wide range of applications. Control objectives of such systems include high-performance bus voltage regulation and proper load sharing among multiple distributed generators(DGs) under various operating conditions. This paper presents a novel decentralized control algorithm that can guarantee both the transient voltage control performance and realize the predefined load sharing percentages. First, the output-constrained control problem is transformed into an equivalent unconstrained one. Second, a two-step backstepping control algorithm is designed based on the transformed model for bus-voltage regulation. Since the overall control effort can be split proportionally and calculated with locally-measurable signals, decentralized load sharing can be realized. The control design requires neither accurate parameters of the output filters nor load measurement. The stability of the transformed systems under the proposed control algorithm can indirectly guarantee the transient bus voltage performance of the original system. Additionally, the high-performance control design is robust, flexible, and reliable. Switch-level simulations under both normal and fault operating conditions demonstrate the effectiveness of the proposed algorithm.展开更多
Under the resource constraint of low per capita possession of cultivated land and the strategic requirements for ensuring national food security,the intensive and efficient use of cultivated land is an important topic...Under the resource constraint of low per capita possession of cultivated land and the strategic requirements for ensuring national food security,the intensive and efficient use of cultivated land is an important topic for long-term research in China's academic circles. It is an important prerequisite for exploring the moderate scale management of agricultural land. The calculation results of 147 county-level units in Northeast China by DEA method show that in the use efficiency evaluation results of cultivated land of county-level units,the mean values of comprehensive efficiency,pure technical efficiency and scale efficiency were 0. 674,0. 705 and 0. 96,respectively,and the DEA effective units account for about 11%. The effective areas of pure technical efficiency and scale efficiency do not have a high level of superposition. To a certain extent,this also limits the improvement of overall efficiency. In view of the scale of family farmland management,counties and cities with an average per household possession of cultivated land of 1. 71-2. 13 ha can achieve both scale and efficiency through efficiency improvement.展开更多
The food industry has developed into a leading industry in Northeast China.However,various economic indicators have shown a significant downward trend in recent years.Through the systematic analysis of the development...The food industry has developed into a leading industry in Northeast China.However,various economic indicators have shown a significant downward trend in recent years.Through the systematic analysis of the development trend of food industry in Northeast China in the past ten years,especially in 2014,it is found that in the context of stable and smooth operation of the food industry in China,the efficiency of the main processing industries declines in the three northeastern provinces of China,there is a simultaneous decline in the share of output value of the leading industries in the output value of manufacturing sector in three provinces,the collective and individual capital withdrawal is obvious in the paid-up capital,and there is a simultaneous decline in the industrial production and sales rate and the export delivery value.The food industry in Northeast China has plunged into the dilemma of development.Finally,this article puts forward some targeted recommendations from aspects of policy making,industrial agglomeration and enterprise cultivation.展开更多
Dissolved organic matter(DOM) plays an essential role in many geochemical processes,however its complexity, chemical diversity, and molecular composition are poorly understood. Soil samples were collected from 500 veg...Dissolved organic matter(DOM) plays an essential role in many geochemical processes,however its complexity, chemical diversity, and molecular composition are poorly understood. Soil samples were collected from 500 vegetable fields in administrative regions of China' Mainland, of which 122 were selected for further investigation. DOM properties were characterized by three-dimensional excitation-emission matrix(3D-EEM) fuorescence spectroscopy and Fourier transform ion cyclotron resonance mass spectrometry(FTICRMS)(field intensity is 15 Tesla). Our results indicated that the main constituents were UVA humic-like substances, humic-like substances, fulvic acid-like substances, and tyrosine-like substances. A total of 10,989 molecular formulae with a mass range of 100.04 to 799.59 Da were detected, covering the mass spectrometric information of the soil samples from 27 different regions. CHO and CHON molecules were dominant in DOM, whereas lignin, tannins,and aromatic substances served as the main components. The results of cluster analysis revealed that the soil properties in Jiangxi Province were considerably different from those in other regions. The key backgrounds of the DOM molecular characteristics in the vegetablefield soil samples across China' Mainland were provided at the molecular level, with large abundance and great variability.展开更多
This paper examines the data of A-share listed companies in China from 2002 to 2017,drawing on the theory of equal opportunity and market rules in M&A transactions.This paper investigates the correlation between c...This paper examines the data of A-share listed companies in China from 2002 to 2017,drawing on the theory of equal opportunity and market rules in M&A transactions.This paper investigates the correlation between changes in tender offer policy and M&A tendencies and performance.The findings suggest that following the policy shift and the adoption of market rules,companies that secure an exemption from the mandatory tender offer obligation not only exhibit stronger M&A tendencies but also improved long-term M&A performance.This indicates that market rules are more suitable for China and contribute to enhancing the efficiency of the M&A market.The paper also presents evidence of a moderating effect,demonstrating that exemptions from the mandatory tender offer obligation positively influence the relationship between policy change and M&A performance.Lastly,this paper finds that state-owned and large-scale firms tend to exhibit a higher degree of M&A tendencies.展开更多
Soil salinity severely limits crop yields and quality.Plants have evolved several strategies to mitigate the adverse effects of salinity,including redistribution and compartmentalization of toxic ions using ion-specif...Soil salinity severely limits crop yields and quality.Plants have evolved several strategies to mitigate the adverse effects of salinity,including redistribution and compartmentalization of toxic ions using ion-specific transporters.However,the mechanisms underlying the regulation of these ion transporters have not been fully elucidated.Loss-of-function mutants of OsHKT2;1,which is involved in sodium uptake,exhibit strong salt stress-resistant phenotypes.In this study,OsHKT2;1 was identified as a transcriptional target of the type-B response regulator OsRR22.Loss-of-function osrr22 mutants showed resilience to salt stress,and OsRR22-overexpression plants were sensitive to salt stress.OsRR22 was found to activate the expression of OsHKT2;1 by directly binding to the promoter region of OsHKT2;1 via a consensus cis-element of type-B response regulators.Moreover,rice DELLA protein OsSLR1 directly interacted with OsRR22 and functioned as a transcriptional co-activator.This study has uncovered a novel transcriptional regulatory mechanism by which a type-B response regulator controls sodium transport under salinity stress.展开更多
Terahertz(THz)technologies have become a focus of research in recent years due to their prominent role in envisioned future communication and sensing systems.One of the key challenges facing the field is the need for ...Terahertz(THz)technologies have become a focus of research in recent years due to their prominent role in envisioned future communication and sensing systems.One of the key challenges facing the field is the need for tools to enable agile engineering of THz wave fronts.Here,we describe a reconfigurable metasurface based on GaN technology with an array-of-subarrays architecture.This subwavelength-spaced array,under the control of a 1-bit digital coding sequence,can switch between an enormous range of possible configurations,providing facile access to nearly arbitrary wave front control for signals near 0.34 THz.We demonstrate wide-angle beam scanning with 1°of angular precision over 70 GHz of bandwidth,as well as the generation of multi-beam and diffuse wave fronts,with a switching speed up to 100 MHz.This device,offering the ability to rapidly reconfigure a propagating wave front for beam-forming or diffusively scattered wide-angle coverage of a scene,will open new realms of possibilities in sensing,imaging,and networking.展开更多
Regional characterization of soil properties requires not only geostatistical models considering the spatial variability of soil properties but also methods that account for various sources of heterogeneous informatio...Regional characterization of soil properties requires not only geostatistical models considering the spatial variability of soil properties but also methods that account for various sources of heterogeneous information.This paper presents a multi-conditional random field approach to characterize the regional characteristics of the average shear-wave velocity in the top 30 meters of subsoil(vs30)based on hybrid geotechnical and geological data.The workflow for integrating multiple sources of soil properties information in a random field model for regional vs30 mapping is developed.A detailed two-dimensional(2D)synthetic digital soil field is generated to assess and verify this workflow.With the generated synthetic field,parametric studies on the investigation plans,the value of Markov Bayes coefficient B,element size,and a predefined grid of secondary data are performed.Practice on whether to incorporate secondary data for vs30 mapping and the determination of coefficient B are provided.展开更多
Root system architecture (RSA) plays an important role in phosphorus (P) acquisition, but enhancing P use efficiency (PUE) in maize via genetic manipulation of RSA has not yet been reported. Here, using a maize ...Root system architecture (RSA) plays an important role in phosphorus (P) acquisition, but enhancing P use efficiency (PUE) in maize via genetic manipulation of RSA has not yet been reported. Here, using a maize recombinant inbred line (RIL) population, we investigated the genetic relationships between PUE and RSA, and developed P-efficient lines by selection of quantitative trait loci (QTLs) that coincide for both traits. In low-P (LP) fields, P uptake efficiency (PupE) was more closely correlated with PUE (r = 0.48 -0.54), and RSA in hydroponics was significantly related to PupE (r=0.25-0.30) but not to P utilization efficiency (PutE). QTL analysis detected a chromosome region where two QTLs for PUE, three for PupE and three for RSA were assigned into two QTL clusters, Cl-bin3.04a and Cl-bin3.04b. These QTLs had favorable effects from alleles derived from the large-rooted and high-PupE parent. Marker-assisted selection (MAS) identified nine advanced backcross-derived lines carrying Cl-bin3.04a or Cl-bin3.04b that displayed mean increases of 22%-26% in PUE in LP fields. Furthermore, a line L224 pyramiding Cl- binB.04a and Cl-bin3.04b showed enhanced PupE, relying mainly on changes in root morphology, rather than root physiology, under both hydroponic and field conditions. These results highlight the physiological and genetic contributions of RSA to maize PupE, and provide a successful study case of developing P-efficient crops through QTL-based selection.展开更多
A self-designed experimental device was employed to simulate the pyrolytic dismantling process of selected electronic wastes(E-wastes), including printed wiring boards(PWBs)and plastic casings. The generated particula...A self-designed experimental device was employed to simulate the pyrolytic dismantling process of selected electronic wastes(E-wastes), including printed wiring boards(PWBs)and plastic casings. The generated particulate matter(PM) of different particle sizes, carbon monoxide(CO) and carbon dioxide(CO_2) were determined, and the corresponding emission factors(EFs) were estimated. Finer particles with particle sizes of 0.4–2.1 μm accounted for78.9% and 89.3% of PM emitted by the pyrolytic processing of PWBs and plastic casings,respectively, and the corresponding EFs were 9.68 ± 4.81 and 18.49 ± 7.2 g/kg, respectively.The EFs of CO and CO_2 from PWBs and plastic casings were 55.9 ± 26.9 and 1182 ± 439 g/kg,and 133.6 ± 34.6 and 2827 ± 276 g/kg, respectively. Compared with other emission sources,such as coal, biomass, and traffic exhaust, the EFs of E-wastes were relatively higher,especially for PM. There were significant positive correlations(p < 0.05) of the initial contents of carbon and nitrogen in PWBs with the related EFs of PM, CO, and CO_2, while the correlations for plastic casings were insignificant. The EFs of CO of PWBs were significantly positively correlated with the corresponding EFs of PM and the parent polycyclic aromatic hydrocarbons(PAHs); however, the same result was not observed for plastic casings.展开更多
A highly efficient milli-joule-level Q-switched Tm,La:CaF_(2)laser is experimentally demonstrated.By employing an acousto-optic modulator,the diode-pumped pulsed lasers are stably operated at repetition rates ranging ...A highly efficient milli-joule-level Q-switched Tm,La:CaF_(2)laser is experimentally demonstrated.By employing an acousto-optic modulator,the diode-pumped pulsed lasers are stably operated at repetition rates ranging from 500 Hz to 10 kHz.Dual-wavelength operation of 1881.7 nm and 1888.5 nm is achieved with slope efficiency of 64.7%.Up to 1.89 mJ of pulse energy is obtained at a pulse width of 100 ns,corresponding to a peak power of 18.88 kW.These results verified that the Tm,La:CaF_(2)crystal could be a promising candidate for achieving highly efficient and high-energy pulsed lasers.展开更多
The glucose sensor HEXOKINASE1(HXK1)integrates myriad external and internal signals to regulate gene expression and development in Arabidopsis thaliana.However,how HXK1 mediates glucose signaling in the nucleus remain...The glucose sensor HEXOKINASE1(HXK1)integrates myriad external and internal signals to regulate gene expression and development in Arabidopsis thaliana.However,how HXK1 mediates glucose signaling in the nucleus remains unclear.Here,using immunoprecipitationcoupled mass spectrometry,we show that two catalytic subunits of Polycomb Repressive Complex 2,SWINGER(SWN)and CURLY LEAF(CLF),directly interact with catalytically active HXK1 and its inactive forms(HXK1^(G104D) and HXK1^(S177A))via their evolutionarily conserved SANT domains.HXK1,CLF,and SWN target common glucose-responsive genes to regulate glucose signaling,as revealed by RNA sequencing.The glucose-insensitive phenotypes of the Arabidopsis swn-1 and clf-50 mutants were similar to that of hxk1,and genetic analysis revealed that CLF,SWN,and HXK1 function in the same genetic pathway.Intriguingly,HXK1 is required for CLF-and SWN-mediated histone H3 lysine 27(H3K27me3)deposition and glucose-mediated gene repression.Moreover,CLF and SWN affect the recruitment of HXK1 to its target chromatin.These findings support a model in which HXK1 and epigenetic modifiers form a nuclear complex to cooperatively mediate glucose signaling,thereby affecting the histone modification and expression of glucoseregulated genes in plants.展开更多
基金financially supported by the National Key Research and Development Program of China (2021YFD1200700)the National Natural Science Foundation of China (31972485,31971948)the Hainan Provincial Science and Technology Plan Sanya Yazhou Bay Science and Technology City Joint Project(320LH011)。
文摘Although the use of heterosis in maize breeding has increased crop productivity,the genetic causes underlying heterosis for nitrogen(N) use efficiency(NUE) have been insufficiently investigated.In this study,five N-response traits and five low-N-tolerance traits were investigated using two inbred line populations(ILs) consisting of recombinant inbred lines(RIL) and advanced backcross(ABL) populations,derived from crossing Ye478 with Wu312.Both populations were crossed with P178 to construct two testcross populations.IL populations,their testcross populations,and the midparent heterosis(MPH)for NUE were investigated.Kernel weight,kernel number,and kernel number per row were sensitive to N level and ILs showed higher N response than did the testcross populations.Based on a highdensity linkage map,138 quantitative trait loci(QTL) were mapped,each explaining 5.6%–38.8% of genetic variation.There were 52,34 and 52 QTL for IL populations,MPH,and testcross populations,respectively.The finding that 7.6% of QTL were common to the ILs and their testcross populations and that 11.7% were common to the MPH and testcross population indicated that heterosis for NUE traits was regulated by non-additive and non-dominant loci.A QTL on chromosome 5 explained 27% of genetic variation in all of the traits and Gln1-3 was identified as a candidate gene for this QTL.Genome-wide prediction of NUE traits in the testcross populations showed 14%–51% accuracy.Our results may be useful for clarifying the genetic basis of heterosis for NUE traits and the candidate gene may be used for genetic improvement of maize NUE.
基金supported by the research grant of Sailing Plan Key Specialty (ZYLX202132) from Beijing Chaoyang HospitalCapital Medical University,Beijing,China。
文摘Mucormycosis is an uncommon and opportunistic fungal infection with high mortality. Infections may result from ingestion of contaminated food, inhalation of spores into the respiratory tract or inoculation into disruptedskin.^([1])Pulmonarymucormycosis(PM)is the most common clinical type.
文摘Objective: Emerging evidence indicates that long non-coding RNAs(lnc RNAs) are critical in carcinogenesis and progression of ovarian cancer. This study aimed to explore the functions and molecular mechanisms of plasmacytoma variant translocation I(PVT1) in ovarian cancer Methods: PVT1 and miR-214 were detected by qRT-PCR assays in ovarian cancer tissues and cells. The cell proliferation,migration, and invasion abilities were detected by cell functional experiments, respectively. Western blot assay was performed to detect epithelial-mesenchymal transition(EMT) markers. MiR-214 expression regulated by PVT1 was studied by RNA immunoprecipitation(RIP) and chromatin immunoprecipitation(Ch IP) assays.Results: The expression of PVT1 was up-regulated in ovarian cancer tissues and cell lines. Elevated PVT1 expression was associated with advanced stage and indicated poor prognosis for ovarian cancer patients. The knockdown of PVT1 impaired SKOV3 cell proliferation, migration, and invasion in vitro. The promotion of ovarian cancer progression by PVT1 involved in regulation of the epithelial-mesenchymal transition process and PVT1 interaction with EZH2 represses miR-214 expression in ovarian cancer cells.Conclusions: PVT1 plays an important role in ovarian cancer tumorigenesis, which might be as a novel diagnostic marker and therapeutic target for ovarian cancer.
基金supported in part by the US Office of Naval Research(N00014-16-1-312,N00014-18-1-2185)in part by the National Natural Science Foundation of China(61673347,U1609214,61751205)
文摘A microgrid is hard to control due to its reduced inertia and increased uncertainties. To overcome the challenges of microgrid control, advanced controllers need to be developed.In this paper, a distributed, two-level, communication-economic control scheme is presented for multiple-bus microgrids with each bus having multiple distributed generators(DGs) connected in parallel. The control objective of the upper level is to calculate the voltage references for one-bus subsystems. The objectives of the lower control level are to make the subsystems' bus voltages track the voltage references and to enhance load current sharing accuracy among the local DGs. Firstly, a distributed consensusbased power sharing algorithm is introduced to determine the power generations of the subsystems. Secondly, a discrete-time droop equation is used to adjust subsystem frequencies for voltage reference calculations. Finally, a Lyapunov-based decentralized control algorithm is designed for bus voltage regulation and proportional load current sharing. Extensive simulation studies with microgrid models of different levels of detail are performed to demonstrate the merits of the proposed control scheme.
基金supported by the U.S.Office of Naval Research(N00014-21-1-2175)。
文摘This article presents a distributed periodic eventtriggered(PET)optimal control scheme to achieve generation cost minimization and average bus voltage regulation in DC microgrids.In order to accommodate the generation constraints of the distributed generators(DGs),a virtual incremental cost is firstly designed,based on which an optimality condition is derived to facilitate the control design.To meet the discrete-time(DT)nature of modern control systems,the optimal controller is directly developed in the DT domain.Afterward,to reduce the communication requirement among the controllers,a distributed event-triggered mechanism is introduced for the DT optimal controller.The event-triggered condition is detected periodically and therefore naturally avoids the Zeno phenomenon.The closed-loop system stability is proved by the Lyapunov synthesis for switched systems.The generation cost minimization and average bus voltage regulation are obtained at the equilibrium point.Finally,switch-level microgrid simulations validate the performance of the proposed optimal controller.
文摘The large inertia of a traditional power system slows down system's frequency response but also allows decent time for controlling the system.Since an autonomous renewable microgrid usually has much smaller inertia,the control system must be very fast and accurate to fight against the small inertia and uncertainties.To reduce the demanding requirements on control,this paper proposes to increase the inertia of photovoltaic(PV) system through inertia emulation.The inertia emulation is realized by controlling the charging/discharging of the direct current(DC)-link capacitor over a certain range and adjusting the PV generation when it is feasible and/or necessary.By well designing the inertia,the DC-link capacitor parameters and the control range,the negative impact of inertia emulation on energy efficiency can be reduced.The proposed algorithm can be integrated with distributed generation setting algorithms to improve dynamic performance and lower implementation requirements.Simulation studies demonstrate the effectiveness of the proposed solution.
基金This work was supported by the National Key Research and Development Program of China(2016YFD0101200 and 2018YFD0100200)the Scientific Research Foundation for the Returned Overseas Chinese Scholars,Ministry of Education.
文摘Genome-wide prediction is a promising approach to boost selection gain in hybrid breeding.Our main objective was to evaluate the potential and limits of genome-wide prediction to identify superior hybrid combinations adapted to Northwest China.A total of 490 hybrids derived from crosses among 119 inbred lines from the Shaan A and Shaan B heterotic pattern were used for genome-wide prediction of ten agronomic traits.We tested eight different statistical prediction models considering additive(A)effects and in addition evaluated the impact of dominance(D)and epistasis(E)on the prediction ability.Employing five-fold cross validation,we show that the average prediction ability ranged from 0.386 to 0.794 across traits and models.Six parametric methods,i.e.ridge regression,LASSO,Elastic Net,Bayes B,Bayes C and reproducing kernel Hilbert space(RKHS)approach,displayed a very similar prediction ability for each trait and two non-parametric methods(random forest and support vector machine)had a higher prediction performance for the trait rind penetrometer resistance of the third internode above ground(RPR_TIAG).The models of A+D RKHS and A+D+E RKHS were slightly better for predicting traits with a relatively high non-additive variance.Integrating trait-specific markers into the A+D RKHS model improved the prediction ability of grain yield by 3%,from 0.528 to 0.558.Of all 6328 potential hybrids,selection of the top 44 hybrids would lead to a 6%increase in grain yield compared with Zhengdan 958,a commercially successful hybrid variety.In conclusion,our results substantiate the value of genome-wide prediction for hybrid breeding and suggest dozens of promising single crosses for developing high-yielding hybrids for Northwest China.
基金supported in part by the U.S.Office of Naval Research(N00014-16-1-3121,N00014-18-1-2185)the National Natural Science Foundation of China(61673347,U1609214,61751205)
文摘A single-bus DC microgrid can represent a wide range of applications. Control objectives of such systems include high-performance bus voltage regulation and proper load sharing among multiple distributed generators(DGs) under various operating conditions. This paper presents a novel decentralized control algorithm that can guarantee both the transient voltage control performance and realize the predefined load sharing percentages. First, the output-constrained control problem is transformed into an equivalent unconstrained one. Second, a two-step backstepping control algorithm is designed based on the transformed model for bus-voltage regulation. Since the overall control effort can be split proportionally and calculated with locally-measurable signals, decentralized load sharing can be realized. The control design requires neither accurate parameters of the output filters nor load measurement. The stability of the transformed systems under the proposed control algorithm can indirectly guarantee the transient bus voltage performance of the original system. Additionally, the high-performance control design is robust, flexible, and reliable. Switch-level simulations under both normal and fault operating conditions demonstrate the effectiveness of the proposed algorithm.
基金Supported by "135" Planning Project of Northeast Institute of Geography and Agroecology,Chinese Academy of Sciences(Y6H2091001-3)National Natural Science Foundation of China(41301111,41601124)Key Project of Chinese Academy of Sciences(KFZD-SW-314,ZDBS-SSW-SQC)
文摘Under the resource constraint of low per capita possession of cultivated land and the strategic requirements for ensuring national food security,the intensive and efficient use of cultivated land is an important topic for long-term research in China's academic circles. It is an important prerequisite for exploring the moderate scale management of agricultural land. The calculation results of 147 county-level units in Northeast China by DEA method show that in the use efficiency evaluation results of cultivated land of county-level units,the mean values of comprehensive efficiency,pure technical efficiency and scale efficiency were 0. 674,0. 705 and 0. 96,respectively,and the DEA effective units account for about 11%. The effective areas of pure technical efficiency and scale efficiency do not have a high level of superposition. To a certain extent,this also limits the improvement of overall efficiency. In view of the scale of family farmland management,counties and cities with an average per household possession of cultivated land of 1. 71-2. 13 ha can achieve both scale and efficiency through efficiency improvement.
基金Supported by National Natural Science Foundation of China(41301111)the "Thirteenth Five-Year Plan" Project of Northeast Institute of Geography and Agroecology of Chinese Academy of Sciences(Y6H2091001-3)
文摘The food industry has developed into a leading industry in Northeast China.However,various economic indicators have shown a significant downward trend in recent years.Through the systematic analysis of the development trend of food industry in Northeast China in the past ten years,especially in 2014,it is found that in the context of stable and smooth operation of the food industry in China,the efficiency of the main processing industries declines in the three northeastern provinces of China,there is a simultaneous decline in the share of output value of the leading industries in the output value of manufacturing sector in three provinces,the collective and individual capital withdrawal is obvious in the paid-up capital,and there is a simultaneous decline in the industrial production and sales rate and the export delivery value.The food industry in Northeast China has plunged into the dilemma of development.Finally,this article puts forward some targeted recommendations from aspects of policy making,industrial agglomeration and enterprise cultivation.
基金supported by the Second Tibetan Plateau Scientific Expedition and Research Program (STEP,No.2019QZKK0304)the Fundamental Research Funds for the Central Universities (No.E2EG0502×2)the Natural Science Foundation Committee of China (No.41991310)。
文摘Dissolved organic matter(DOM) plays an essential role in many geochemical processes,however its complexity, chemical diversity, and molecular composition are poorly understood. Soil samples were collected from 500 vegetable fields in administrative regions of China' Mainland, of which 122 were selected for further investigation. DOM properties were characterized by three-dimensional excitation-emission matrix(3D-EEM) fuorescence spectroscopy and Fourier transform ion cyclotron resonance mass spectrometry(FTICRMS)(field intensity is 15 Tesla). Our results indicated that the main constituents were UVA humic-like substances, humic-like substances, fulvic acid-like substances, and tyrosine-like substances. A total of 10,989 molecular formulae with a mass range of 100.04 to 799.59 Da were detected, covering the mass spectrometric information of the soil samples from 27 different regions. CHO and CHON molecules were dominant in DOM, whereas lignin, tannins,and aromatic substances served as the main components. The results of cluster analysis revealed that the soil properties in Jiangxi Province were considerably different from those in other regions. The key backgrounds of the DOM molecular characteristics in the vegetablefield soil samples across China' Mainland were provided at the molecular level, with large abundance and great variability.
基金Supported by Guangdong Province Philosophy and Social Science Planning Project(GD22CGL41,GD23XGL062,GD24CYJ20)Guangdong Basic and Applied Basic Research Foundation(2021A1515011479)。
文摘This paper examines the data of A-share listed companies in China from 2002 to 2017,drawing on the theory of equal opportunity and market rules in M&A transactions.This paper investigates the correlation between changes in tender offer policy and M&A tendencies and performance.The findings suggest that following the policy shift and the adoption of market rules,companies that secure an exemption from the mandatory tender offer obligation not only exhibit stronger M&A tendencies but also improved long-term M&A performance.This indicates that market rules are more suitable for China and contribute to enhancing the efficiency of the M&A market.The paper also presents evidence of a moderating effect,demonstrating that exemptions from the mandatory tender offer obligation positively influence the relationship between policy change and M&A performance.Lastly,this paper finds that state-owned and large-scale firms tend to exhibit a higher degree of M&A tendencies.
基金supported by the National Natural Science Foundation of China (32001448,32272027)。
文摘Soil salinity severely limits crop yields and quality.Plants have evolved several strategies to mitigate the adverse effects of salinity,including redistribution and compartmentalization of toxic ions using ion-specific transporters.However,the mechanisms underlying the regulation of these ion transporters have not been fully elucidated.Loss-of-function mutants of OsHKT2;1,which is involved in sodium uptake,exhibit strong salt stress-resistant phenotypes.In this study,OsHKT2;1 was identified as a transcriptional target of the type-B response regulator OsRR22.Loss-of-function osrr22 mutants showed resilience to salt stress,and OsRR22-overexpression plants were sensitive to salt stress.OsRR22 was found to activate the expression of OsHKT2;1 by directly binding to the promoter region of OsHKT2;1 via a consensus cis-element of type-B response regulators.Moreover,rice DELLA protein OsSLR1 directly interacted with OsRR22 and functioned as a transcriptional co-activator.This study has uncovered a novel transcriptional regulatory mechanism by which a type-B response regulator controls sodium transport under salinity stress.
基金This work was financially supported by National Key Research and Development Program of China(2021YFA1401000)National Natural Science Foundation of China(U20A20212,61931006,62131007,61921002,62101111 and 61901093)+2 种基金Fundamental Research Funds for the Central Universities(ZYGX2020ZB011)China Postdoctoral Science Foundation(2020M683285)the US National Science Foundation grant(1923782,1954780 and 2211616).
文摘Terahertz(THz)technologies have become a focus of research in recent years due to their prominent role in envisioned future communication and sensing systems.One of the key challenges facing the field is the need for tools to enable agile engineering of THz wave fronts.Here,we describe a reconfigurable metasurface based on GaN technology with an array-of-subarrays architecture.This subwavelength-spaced array,under the control of a 1-bit digital coding sequence,can switch between an enormous range of possible configurations,providing facile access to nearly arbitrary wave front control for signals near 0.34 THz.We demonstrate wide-angle beam scanning with 1°of angular precision over 70 GHz of bandwidth,as well as the generation of multi-beam and diffuse wave fronts,with a switching speed up to 100 MHz.This device,offering the ability to rapidly reconfigure a propagating wave front for beam-forming or diffusively scattered wide-angle coverage of a scene,will open new realms of possibilities in sensing,imaging,and networking.
基金supported by the National Natural Science Foundation of China(Grant No.5210082052)the Zhejiang Provincial Natural Science Foundation,China(Grant No.LQ22E080028)the Science Foundation of Zhejiang Sci-Tech University,China(Grant No.19052459-Y).
文摘Regional characterization of soil properties requires not only geostatistical models considering the spatial variability of soil properties but also methods that account for various sources of heterogeneous information.This paper presents a multi-conditional random field approach to characterize the regional characteristics of the average shear-wave velocity in the top 30 meters of subsoil(vs30)based on hybrid geotechnical and geological data.The workflow for integrating multiple sources of soil properties information in a random field model for regional vs30 mapping is developed.A detailed two-dimensional(2D)synthetic digital soil field is generated to assess and verify this workflow.With the generated synthetic field,parametric studies on the investigation plans,the value of Markov Bayes coefficient B,element size,and a predefined grid of secondary data are performed.Practice on whether to incorporate secondary data for vs30 mapping and the determination of coefficient B are provided.
基金financially supported by the National Key Research and Development Program of China(No.2016YFD0100700)the National Science Foundation of China(Nos.31572186 and 31421092)
文摘Root system architecture (RSA) plays an important role in phosphorus (P) acquisition, but enhancing P use efficiency (PUE) in maize via genetic manipulation of RSA has not yet been reported. Here, using a maize recombinant inbred line (RIL) population, we investigated the genetic relationships between PUE and RSA, and developed P-efficient lines by selection of quantitative trait loci (QTLs) that coincide for both traits. In low-P (LP) fields, P uptake efficiency (PupE) was more closely correlated with PUE (r = 0.48 -0.54), and RSA in hydroponics was significantly related to PupE (r=0.25-0.30) but not to P utilization efficiency (PutE). QTL analysis detected a chromosome region where two QTLs for PUE, three for PupE and three for RSA were assigned into two QTL clusters, Cl-bin3.04a and Cl-bin3.04b. These QTLs had favorable effects from alleles derived from the large-rooted and high-PupE parent. Marker-assisted selection (MAS) identified nine advanced backcross-derived lines carrying Cl-bin3.04a or Cl-bin3.04b that displayed mean increases of 22%-26% in PUE in LP fields. Furthermore, a line L224 pyramiding Cl- binB.04a and Cl-bin3.04b showed enhanced PupE, relying mainly on changes in root morphology, rather than root physiology, under both hydroponic and field conditions. These results highlight the physiological and genetic contributions of RSA to maize PupE, and provide a successful study case of developing P-efficient crops through QTL-based selection.
基金supported by the Natural Science Foundation Committee of China(No.41390240)the National Basic Research Program of China(No.2014CB441101)
文摘A self-designed experimental device was employed to simulate the pyrolytic dismantling process of selected electronic wastes(E-wastes), including printed wiring boards(PWBs)and plastic casings. The generated particulate matter(PM) of different particle sizes, carbon monoxide(CO) and carbon dioxide(CO_2) were determined, and the corresponding emission factors(EFs) were estimated. Finer particles with particle sizes of 0.4–2.1 μm accounted for78.9% and 89.3% of PM emitted by the pyrolytic processing of PWBs and plastic casings,respectively, and the corresponding EFs were 9.68 ± 4.81 and 18.49 ± 7.2 g/kg, respectively.The EFs of CO and CO_2 from PWBs and plastic casings were 55.9 ± 26.9 and 1182 ± 439 g/kg,and 133.6 ± 34.6 and 2827 ± 276 g/kg, respectively. Compared with other emission sources,such as coal, biomass, and traffic exhaust, the EFs of E-wastes were relatively higher,especially for PM. There were significant positive correlations(p < 0.05) of the initial contents of carbon and nitrogen in PWBs with the related EFs of PM, CO, and CO_2, while the correlations for plastic casings were insignificant. The EFs of CO of PWBs were significantly positively correlated with the corresponding EFs of PM and the parent polycyclic aromatic hydrocarbons(PAHs); however, the same result was not observed for plastic casings.
基金financially supported by the National Natural Science Foundation of China(Nos.11974220,61635012,and 61925508)Science and Technology Commission of Shanghai Municipality(No.20511107400)+1 种基金CAS Interdisciplinary Innovation Team(No.ICTD 2019-12)Natural Science Foundation of Shandong Province(No.ZR2021LLZ008).
文摘A highly efficient milli-joule-level Q-switched Tm,La:CaF_(2)laser is experimentally demonstrated.By employing an acousto-optic modulator,the diode-pumped pulsed lasers are stably operated at repetition rates ranging from 500 Hz to 10 kHz.Dual-wavelength operation of 1881.7 nm and 1888.5 nm is achieved with slope efficiency of 64.7%.Up to 1.89 mJ of pulse energy is obtained at a pulse width of 100 ns,corresponding to a peak power of 18.88 kW.These results verified that the Tm,La:CaF_(2)crystal could be a promising candidate for achieving highly efficient and high-energy pulsed lasers.
基金supported by the National Natural Science Foundation of China (31971822 to Z.-Y.X. and 32001448 to Y.L.)China Postdoctoral Science Foundation (2020M670828 to Y.L.)the Fundamental Research Funds for the Central Universities (2412020QD020 to Y.L.)
文摘The glucose sensor HEXOKINASE1(HXK1)integrates myriad external and internal signals to regulate gene expression and development in Arabidopsis thaliana.However,how HXK1 mediates glucose signaling in the nucleus remains unclear.Here,using immunoprecipitationcoupled mass spectrometry,we show that two catalytic subunits of Polycomb Repressive Complex 2,SWINGER(SWN)and CURLY LEAF(CLF),directly interact with catalytically active HXK1 and its inactive forms(HXK1^(G104D) and HXK1^(S177A))via their evolutionarily conserved SANT domains.HXK1,CLF,and SWN target common glucose-responsive genes to regulate glucose signaling,as revealed by RNA sequencing.The glucose-insensitive phenotypes of the Arabidopsis swn-1 and clf-50 mutants were similar to that of hxk1,and genetic analysis revealed that CLF,SWN,and HXK1 function in the same genetic pathway.Intriguingly,HXK1 is required for CLF-and SWN-mediated histone H3 lysine 27(H3K27me3)deposition and glucose-mediated gene repression.Moreover,CLF and SWN affect the recruitment of HXK1 to its target chromatin.These findings support a model in which HXK1 and epigenetic modifiers form a nuclear complex to cooperatively mediate glucose signaling,thereby affecting the histone modification and expression of glucoseregulated genes in plants.