During the use of robotics in applications such as antiterrorism or combat,a motion-constrained pursuer vehicle,such as a Dubins unmanned surface vehicle(USV),must get close enough(within a prescribed zero or positive...During the use of robotics in applications such as antiterrorism or combat,a motion-constrained pursuer vehicle,such as a Dubins unmanned surface vehicle(USV),must get close enough(within a prescribed zero or positive distance)to a moving target as quickly as possible,resulting in the extended minimum-time intercept problem(EMTIP).Existing research has primarily focused on the zero-distance intercept problem,MTIP,establishing the necessary or sufficient conditions for MTIP optimality,and utilizing analytic algorithms,such as root-finding algorithms,to calculate the optimal solutions.However,these approaches depend heavily on the properties of the analytic algorithm,making them inapplicable when problem settings change,such as in the case of a positive effective range or complicated target motions outside uniform rectilinear motion.In this study,an approach employing a high-accuracy and quality-guaranteed mixed-integer piecewise-linear program(QG-PWL)is proposed for the EMTIP.This program can accommodate different effective interception ranges and complicated target motions(variable velocity or complicated trajectories).The high accuracy and quality guarantees of QG-PWL originate from elegant strategies such as piecewise linearization and other developed operation strategies.The approximate error in the intercept path length is proved to be bounded to h^(2)/(4√2),where h is the piecewise length.展开更多
Fine-grained nuclear graphite is a key material in high-temperature gas-cooled reactors(HTGRs).During air ingress accidents,core graphite components undergo severe oxidation,threatening structural integrity.Therefore,...Fine-grained nuclear graphite is a key material in high-temperature gas-cooled reactors(HTGRs).During air ingress accidents,core graphite components undergo severe oxidation,threatening structural integrity.Therefore,understanding the oxidation behavior of nuclear graphite is essential for reactor safety.The influence of oxidation involves multiple factors,including temperature,sample size,oxidant,impurities,filler type and size,etc.The size of the filler particles plays a crucial role in this study.Five ultrafine-and superfine-grained nuclear graphite samples(5.9-34.4μm)are manufactured using identical raw materials and manufacturing processes.Isothermal oxidation tests conducted at 650℃-750℃ are used to study the oxidation behavior.Additionally,comprehensive characterization is performed to analyze the crystal structure,surface morphology,and nanoscale to microscale pore structure of the samples.Results indicate that oxidation behavior cannot be predicted solely based on filler grain size.Reactive site concentration,characterized by active surface area,dominates the chemical reaction kinetics,whereas pore tortuosity,quantified by the structural parameterΨ,plays a key role in regulating oxidant diffusion.These findings clarify the dual role of microstructure in oxidation mechanisms and establish a theoretical and experimental basis for the design of high-performance nuclear graphite capable of long-term service in high-temperature gas-cooled reactors.展开更多
Melamine sponge is a major concern for oil-water separation due to its lightweight,high porosity(>99%),cost-effectiveness,impressive mechanical properties,and chemical/thermal stability.However,its amphiphilic natu...Melamine sponge is a major concern for oil-water separation due to its lightweight,high porosity(>99%),cost-effectiveness,impressive mechanical properties,and chemical/thermal stability.However,its amphiphilic nature hinders selective oil absorption in water.Recent strategies to enhance hydrophobicity are reviewed,including synthetic methods and materials,with comprehensive explanations of the mechanisms driven by surface energy and roughness.Key performance indicators for MS in oil-water separation,including adsorption capacity,wettability,stability,emulsion separation,reversible wettability switching,flame retardancy,mechanical properties,and recyclability,are thoroughly discussed.In conclusion,this review provides insights into the future potential and direction of functional melamine sponges in oil-water separation.展开更多
Sodium-ion batteries (SIBs) with organic electrodes are an emerging research direction due to the sustainability of organic materials based on elements like C,H,O,and sodium ions.Currently,organic electrode materials ...Sodium-ion batteries (SIBs) with organic electrodes are an emerging research direction due to the sustainability of organic materials based on elements like C,H,O,and sodium ions.Currently,organic electrode materials for SIBs are mainly used as cathodes because of their relatively high redox potentials(>1 V).Organic electrodes with low redox potential that can be used as anode are rare.Herein,a novel organic anode material (tetrasodium 1,4,5,8-naphthalenetetracarboxylate,Na_(4)TDC) has been developed with low redox potential (<0.7 V) and excellent cyclic stability.Its three-sodium storage mechanism was demonstrated with various in-situ/ex-situ spectroscopy and theoretical calculations,showing a high capacity of 208 mAh/g and an average decay rate of merely 0.022%per cycle.Moreover,the Na_(4)TDC-hard carbon composite can further acquire improved capacity and cycling stability for 1200 cycles even with a high mass loading of up to 20 mg cm^(-2).By pairing with a thick Na_(3)V_(2)(PO_(4))_(3)cathode (20.6 mg cm^(-2)),the as-fabricated full cell exhibited high operating voltage (2.8 V),excellent rate performance and cycling stability with a high capacity retention of 88.7% after 200 cycles,well highlighting the Na_(4)TDC anode material for SIBs.展开更多
BACKGROUND Noonan syndrome is a relatively common autosomal dominant genetic disorder characterized by cardiovascular defects owing to functional abnormalities in key genes such as RAF1.Mutations in RAF1 are typically...BACKGROUND Noonan syndrome is a relatively common autosomal dominant genetic disorder characterized by cardiovascular defects owing to functional abnormalities in key genes such as RAF1.Mutations in RAF1 are typically associated with hypertrophic cardiomyopathy(HCM).However,in this case,the patient exhibited atrial and ventricular septal defects(VSDs).CASE SUMMARY This case report describes an 11-year-old boy diagnosed with Noonan syndrome,in whom genetic testing revealed a c.770C>T(p.Ser257 Leu)mutation in RAF1.The patient presented with intermittent chest discomfort and shortness of breath,symptoms that significantly worsened after physical activity.Clinical evaluation revealed marked growth retardation and multiple physical abnormalities.Electrocardiographic and echocardiographic assessments revealed VSDs,atrial septal defects,and left ventricular outflow tract obstruction.Following multidisciplinary consultation,the patient underwent cardiac surgical intervention,which led to clinical improvement;however,they subsequently developed a third-degree atrioventricular block,necessitating the implantation of a permanent pacemaker.During follow-up,echocardiographic findings demonstrated near-complete resolution of the shunt across the atrial and ventricular septa,significant improvement in left ventricular outflow tract obstruction,and notable reduction in ventricular septal thickness.A genetic mutation at the c.770C>T(p.Ser257 Leu)locus of RAF1 is typically associated with HCM and pulmonary hypertension.However,this patient’s clinical phenotype manifested as HCM,atrial septal defect,and VSD,suggesting that this mutation may involve a different pathophysiological mechanism.CONCLUSION This case confirms the genotype-phenotype heterogeneity of Noonan syndrome and highlights the complex management requirements of RAF1 mutation-associated cardiac pathologies.Early surgical intervention can ameliorate structural defects,but it must be integrated with genetic counseling and lifelong monitoring to optimize patient outcomes.展开更多
The selective addition reaction of unsaturated C-C bonds has always been a classic and constant research topic.Different from well-developed hydroboration,hydrosilylation,and hydrostannylation reaction,hydrogermylatio...The selective addition reaction of unsaturated C-C bonds has always been a classic and constant research topic.Different from well-developed hydroboration,hydrosilylation,and hydrostannylation reaction,hydrogermylation reaction remains challenging which hasn't been much reported.Herein,we developed a new metal-porous ligand polymers Pd1@POL-PPh_(n)Cy_(m)(n+m=3)with monoatomic dispersion characteristics for highly selective and efficient hydrogermylation of unsaturated C-C bonds,including alkynes,alkenes,and allenes.X-ray photoelectron spectroscopy and theoretical calculations further proved the introduction of cyclohexyl could gently adjust the charge on monoatomic Pd center which effectively facilitate the recognition and transformation of various substrates.With the electrically fine-tuned single atom palladium catalysts,we realized theα-germanium addition for the first time,obtaining corresponding allyl germanium and alkyl germanium compounds.展开更多
The complex vibration directly affects the dynamic safety of drill string in ultra-deep wells and extra-deep wells.It is important to understand the dynamic characteristics of drill string to ensure the safety of dril...The complex vibration directly affects the dynamic safety of drill string in ultra-deep wells and extra-deep wells.It is important to understand the dynamic characteristics of drill string to ensure the safety of drill string.Due to the super slenderness ratio of drill string,strong nonlinearity implied in dynamic analysis and the complex load environment,dynamic simulation of drill string faces great challenges.At present,many simulation methods have been developed to analyze drill string dynamics,and node iteration method is one of them.The node iteration method has a unique advantage in dealing with the contact characteristics between drill string and borehole wall,but its drawback is that the calculation consumes a considerable amount of time.This paper presents a dynamic simulation method of drilling string in extra-deep well based on successive over-relaxation node iterative method(SOR node iteration method).Through theoretical analysis and numerical examples,the correctness and validity of this method were verified,and the dynamics characteristics of drill string in extra-deep wells were calculated and analyzed.The results demonstrate that,in contrast to the conventional node iteration method,the SOR node iteration method can increase the computational efficiency by 48.2%while achieving comparable results.And the whirl trajectory of the extra-deep well drill string is extremely complicated,the maximum rotational speed downhole is approximately twice the rotational speed on the ground.The dynamic torque increases rapidly at the position of the bottom stabilizer,and the lateral vibration in the middle and lower parts of drill string is relatively intense.展开更多
The circadian clock is an important internal time regulatory system for a range of physiological and behavioral rhythms within living organisms.Testosterone,as one of the most critical sex hormones,is essential for th...The circadian clock is an important internal time regulatory system for a range of physiological and behavioral rhythms within living organisms.Testosterone,as one of the most critical sex hormones,is essential for the development of the reproductive system,maintenance of reproductive function,and the overall health of males.The secretion of testosterone in mammals is characterized by distinct circadian rhythms and is closely associated with the regulation of circadian clock genes.Here we review the central and peripheral regulatory mechanisms underlying the influence of circadian clock genes upon testosterone synthesis.We also examined the specific effects of these genes on the occurrence,development,and treatment of common male diseases,including late-onset hypogonadism,erectile dysfunction,male infertility,and prostate cancer.展开更多
Dear Editor,Mutations in genomic sequences exhibit a strong correlation with various pathological processes of cancers[1].Currently,the next-generation sequencing technique[2]and polymerase chain reaction(PCR)were the...Dear Editor,Mutations in genomic sequences exhibit a strong correlation with various pathological processes of cancers[1].Currently,the next-generation sequencing technique[2]and polymerase chain reaction(PCR)were the established benchmarks for analyzing DNA mutations.However,the two methods necessitate intricate experimental preparation,costly instrumentation,and skilled personnel,making them challenging for rapid mutations analysis.More importantly,these methods lack adequate accuracy for one base mutations analysis[3].Therefore,the development of a reliable and exceptionally sensitive mutation analysis approach holds immense importance in cancer diagnosis and treatment.展开更多
The O3-type layered cathode with high Ni content has attracted much attention because of its high capacity and simple synthesis process.However,surface side reaction and O3-P3 phase transitions would occur during Na+i...The O3-type layered cathode with high Ni content has attracted much attention because of its high capacity and simple synthesis process.However,surface side reaction and O3-P3 phase transitions would occur during Na+insertion/extraction,resulting in unsatisfying electrochemical performance.Herein,O3-Na[Ni_(0.6)Co_(0.2)Mn_(0.2)]O_(2)(NNCM622)cathode is modified by a NaTiOx coating layer in a wet chemistry method,which reduces the parasitic reaction and facilitates Na+migration.Simultaneously,the partially doped Ti improves structural stability by restraining the irreversible multiple-phase transition.As a result,the modified NNCM622 cathode obtains a high specific capacity of 143.4 mAh g^(−1)and an improved capacity retention of 69%after 300 cycles.Our work offers new prospects for stabilizing the NNCM622 cathode with a feasible coating strategy.展开更多
基金supported by the National Natural Sci‐ence Foundation of China(Grant No.62306325)。
文摘During the use of robotics in applications such as antiterrorism or combat,a motion-constrained pursuer vehicle,such as a Dubins unmanned surface vehicle(USV),must get close enough(within a prescribed zero or positive distance)to a moving target as quickly as possible,resulting in the extended minimum-time intercept problem(EMTIP).Existing research has primarily focused on the zero-distance intercept problem,MTIP,establishing the necessary or sufficient conditions for MTIP optimality,and utilizing analytic algorithms,such as root-finding algorithms,to calculate the optimal solutions.However,these approaches depend heavily on the properties of the analytic algorithm,making them inapplicable when problem settings change,such as in the case of a positive effective range or complicated target motions outside uniform rectilinear motion.In this study,an approach employing a high-accuracy and quality-guaranteed mixed-integer piecewise-linear program(QG-PWL)is proposed for the EMTIP.This program can accommodate different effective interception ranges and complicated target motions(variable velocity or complicated trajectories).The high accuracy and quality guarantees of QG-PWL originate from elegant strategies such as piecewise linearization and other developed operation strategies.The approximate error in the intercept path length is proved to be bounded to h^(2)/(4√2),where h is the piecewise length.
基金supported by the National Key Research and Development Program of China(2024YFA1612900)the National Natural Science Foundation of China(Grant No.52103365 and No.12375270)the Guangdong Innovative and Entrepreneurial Research Team Program,China(Grant No.2021ZT09L227).
文摘Fine-grained nuclear graphite is a key material in high-temperature gas-cooled reactors(HTGRs).During air ingress accidents,core graphite components undergo severe oxidation,threatening structural integrity.Therefore,understanding the oxidation behavior of nuclear graphite is essential for reactor safety.The influence of oxidation involves multiple factors,including temperature,sample size,oxidant,impurities,filler type and size,etc.The size of the filler particles plays a crucial role in this study.Five ultrafine-and superfine-grained nuclear graphite samples(5.9-34.4μm)are manufactured using identical raw materials and manufacturing processes.Isothermal oxidation tests conducted at 650℃-750℃ are used to study the oxidation behavior.Additionally,comprehensive characterization is performed to analyze the crystal structure,surface morphology,and nanoscale to microscale pore structure of the samples.Results indicate that oxidation behavior cannot be predicted solely based on filler grain size.Reactive site concentration,characterized by active surface area,dominates the chemical reaction kinetics,whereas pore tortuosity,quantified by the structural parameterΨ,plays a key role in regulating oxidant diffusion.These findings clarify the dual role of microstructure in oxidation mechanisms and establish a theoretical and experimental basis for the design of high-performance nuclear graphite capable of long-term service in high-temperature gas-cooled reactors.
基金supported by the National Natural Science Foundation of China(Nos.52372093 and 52102145)the Key R&D Program of Shaanxi Province(Nos.2023GXLH-045 and 2022SF-168)+4 种基金the Xi’an Programs for Science and Technology Plan(Nos.2020KJRC0090 and 21XJZZ0045)the Opening Project of Shanxi Key Laboratory of Advanced Manufacturing Technology(No.XJZZ202001)the Xi’an Municipal Bureau of Science and Technology(No.21XJZZ0054)the Open Foundation of Key Laboratory of Auxiliary Chemistry and Technology for Chemical Industry,Ministry of Education,Shaanxi University of Science and Technology(No.KFKT2021-01)the Shaanxi Collaborative Innovation Center of Industrial Auxiliary Chemistry and Technology,Shaanxi University of Science and Technology(No.KFKT2021-01).
文摘Melamine sponge is a major concern for oil-water separation due to its lightweight,high porosity(>99%),cost-effectiveness,impressive mechanical properties,and chemical/thermal stability.However,its amphiphilic nature hinders selective oil absorption in water.Recent strategies to enhance hydrophobicity are reviewed,including synthetic methods and materials,with comprehensive explanations of the mechanisms driven by surface energy and roughness.Key performance indicators for MS in oil-water separation,including adsorption capacity,wettability,stability,emulsion separation,reversible wettability switching,flame retardancy,mechanical properties,and recyclability,are thoroughly discussed.In conclusion,this review provides insights into the future potential and direction of functional melamine sponges in oil-water separation.
基金National Key Research and Development Program of China (2022YFB2402200)National Natural Science Foundation of China (22225201,22379028)+2 种基金Fundamental Research Funds for the Central Universities (20720220010)Shanghai Pilot Program for Basic Research–Fudan University 21TQ1400100 (21TQ009)Key Basic Research Program of Science and Technology Commission of Shanghai Municipality (23520750400)。
文摘Sodium-ion batteries (SIBs) with organic electrodes are an emerging research direction due to the sustainability of organic materials based on elements like C,H,O,and sodium ions.Currently,organic electrode materials for SIBs are mainly used as cathodes because of their relatively high redox potentials(>1 V).Organic electrodes with low redox potential that can be used as anode are rare.Herein,a novel organic anode material (tetrasodium 1,4,5,8-naphthalenetetracarboxylate,Na_(4)TDC) has been developed with low redox potential (<0.7 V) and excellent cyclic stability.Its three-sodium storage mechanism was demonstrated with various in-situ/ex-situ spectroscopy and theoretical calculations,showing a high capacity of 208 mAh/g and an average decay rate of merely 0.022%per cycle.Moreover,the Na_(4)TDC-hard carbon composite can further acquire improved capacity and cycling stability for 1200 cycles even with a high mass loading of up to 20 mg cm^(-2).By pairing with a thick Na_(3)V_(2)(PO_(4))_(3)cathode (20.6 mg cm^(-2)),the as-fabricated full cell exhibited high operating voltage (2.8 V),excellent rate performance and cycling stability with a high capacity retention of 88.7% after 200 cycles,well highlighting the Na_(4)TDC anode material for SIBs.
基金Supported by the Gansu Provincial Science and Technology Plan Project,No.24JRRA886 and No.23JRRA1287Gansu Provincial People’s Hospital:Excellent Doctoral Student Cultivation Program,No.22GSSYD-14.
文摘BACKGROUND Noonan syndrome is a relatively common autosomal dominant genetic disorder characterized by cardiovascular defects owing to functional abnormalities in key genes such as RAF1.Mutations in RAF1 are typically associated with hypertrophic cardiomyopathy(HCM).However,in this case,the patient exhibited atrial and ventricular septal defects(VSDs).CASE SUMMARY This case report describes an 11-year-old boy diagnosed with Noonan syndrome,in whom genetic testing revealed a c.770C>T(p.Ser257 Leu)mutation in RAF1.The patient presented with intermittent chest discomfort and shortness of breath,symptoms that significantly worsened after physical activity.Clinical evaluation revealed marked growth retardation and multiple physical abnormalities.Electrocardiographic and echocardiographic assessments revealed VSDs,atrial septal defects,and left ventricular outflow tract obstruction.Following multidisciplinary consultation,the patient underwent cardiac surgical intervention,which led to clinical improvement;however,they subsequently developed a third-degree atrioventricular block,necessitating the implantation of a permanent pacemaker.During follow-up,echocardiographic findings demonstrated near-complete resolution of the shunt across the atrial and ventricular septa,significant improvement in left ventricular outflow tract obstruction,and notable reduction in ventricular septal thickness.A genetic mutation at the c.770C>T(p.Ser257 Leu)locus of RAF1 is typically associated with HCM and pulmonary hypertension.However,this patient’s clinical phenotype manifested as HCM,atrial septal defect,and VSD,suggesting that this mutation may involve a different pathophysiological mechanism.CONCLUSION This case confirms the genotype-phenotype heterogeneity of Noonan syndrome and highlights the complex management requirements of RAF1 mutation-associated cardiac pathologies.Early surgical intervention can ameliorate structural defects,but it must be integrated with genetic counseling and lifelong monitoring to optimize patient outcomes.
基金supported by the National Natural Science Foundation of China(Nos.22201049,22471046)the Ba-Gui Youth Top-notch Talents Project of Guangxithe National HighLevel Personnel of Special Support Program for Young Top-notch Talents(9th batch)。
文摘The selective addition reaction of unsaturated C-C bonds has always been a classic and constant research topic.Different from well-developed hydroboration,hydrosilylation,and hydrostannylation reaction,hydrogermylation reaction remains challenging which hasn't been much reported.Herein,we developed a new metal-porous ligand polymers Pd1@POL-PPh_(n)Cy_(m)(n+m=3)with monoatomic dispersion characteristics for highly selective and efficient hydrogermylation of unsaturated C-C bonds,including alkynes,alkenes,and allenes.X-ray photoelectron spectroscopy and theoretical calculations further proved the introduction of cyclohexyl could gently adjust the charge on monoatomic Pd center which effectively facilitate the recognition and transformation of various substrates.With the electrically fine-tuned single atom palladium catalysts,we realized theα-germanium addition for the first time,obtaining corresponding allyl germanium and alkyl germanium compounds.
基金supported by the National Natural Science Foundation of China(52174003,52374008).
文摘The complex vibration directly affects the dynamic safety of drill string in ultra-deep wells and extra-deep wells.It is important to understand the dynamic characteristics of drill string to ensure the safety of drill string.Due to the super slenderness ratio of drill string,strong nonlinearity implied in dynamic analysis and the complex load environment,dynamic simulation of drill string faces great challenges.At present,many simulation methods have been developed to analyze drill string dynamics,and node iteration method is one of them.The node iteration method has a unique advantage in dealing with the contact characteristics between drill string and borehole wall,but its drawback is that the calculation consumes a considerable amount of time.This paper presents a dynamic simulation method of drilling string in extra-deep well based on successive over-relaxation node iterative method(SOR node iteration method).Through theoretical analysis and numerical examples,the correctness and validity of this method were verified,and the dynamics characteristics of drill string in extra-deep wells were calculated and analyzed.The results demonstrate that,in contrast to the conventional node iteration method,the SOR node iteration method can increase the computational efficiency by 48.2%while achieving comparable results.And the whirl trajectory of the extra-deep well drill string is extremely complicated,the maximum rotational speed downhole is approximately twice the rotational speed on the ground.The dynamic torque increases rapidly at the position of the bottom stabilizer,and the lateral vibration in the middle and lower parts of drill string is relatively intense.
基金supported by grants from the National Natural Science Foundation of China(N0.82474525 and No.82074444)the Hunan Provincial Natural Outstanding Young People Science Foundation(2023JJ10032)the Hunan Province Health and High-Level Talent Medical Academic Leader Training Plan(20240304051).
文摘The circadian clock is an important internal time regulatory system for a range of physiological and behavioral rhythms within living organisms.Testosterone,as one of the most critical sex hormones,is essential for the development of the reproductive system,maintenance of reproductive function,and the overall health of males.The secretion of testosterone in mammals is characterized by distinct circadian rhythms and is closely associated with the regulation of circadian clock genes.Here we review the central and peripheral regulatory mechanisms underlying the influence of circadian clock genes upon testosterone synthesis.We also examined the specific effects of these genes on the occurrence,development,and treatment of common male diseases,including late-onset hypogonadism,erectile dysfunction,male infertility,and prostate cancer.
文摘Dear Editor,Mutations in genomic sequences exhibit a strong correlation with various pathological processes of cancers[1].Currently,the next-generation sequencing technique[2]and polymerase chain reaction(PCR)were the established benchmarks for analyzing DNA mutations.However,the two methods necessitate intricate experimental preparation,costly instrumentation,and skilled personnel,making them challenging for rapid mutations analysis.More importantly,these methods lack adequate accuracy for one base mutations analysis[3].Therefore,the development of a reliable and exceptionally sensitive mutation analysis approach holds immense importance in cancer diagnosis and treatment.
基金National Key Research and Development Program of China,Grant/Award Number:2023YFB2406100Yibin‘Jie Bang Gua Shuai’,Grant/Award Number:2022JB003National Natural Science Foundation of China,Grant/Award Number:52172234。
文摘The O3-type layered cathode with high Ni content has attracted much attention because of its high capacity and simple synthesis process.However,surface side reaction and O3-P3 phase transitions would occur during Na+insertion/extraction,resulting in unsatisfying electrochemical performance.Herein,O3-Na[Ni_(0.6)Co_(0.2)Mn_(0.2)]O_(2)(NNCM622)cathode is modified by a NaTiOx coating layer in a wet chemistry method,which reduces the parasitic reaction and facilitates Na+migration.Simultaneously,the partially doped Ti improves structural stability by restraining the irreversible multiple-phase transition.As a result,the modified NNCM622 cathode obtains a high specific capacity of 143.4 mAh g^(−1)and an improved capacity retention of 69%after 300 cycles.Our work offers new prospects for stabilizing the NNCM622 cathode with a feasible coating strategy.
