Perfect quantum state mirroring in a chain of N spins is defined as the condition in which the state 丨i 丨of the chain is swapped into the state 丨N - i丨 within a time evolution interval r. Such a phenomenon is an i...Perfect quantum state mirroring in a chain of N spins is defined as the condition in which the state 丨i 丨of the chain is swapped into the state 丨N - i丨 within a time evolution interval r. Such a phenomenon is an interesting way of transfering entanglement. An expressions for the perfect mirroring of a single qubit contained in a spin chain were proposed in the past. We exploit such an expressions for calculating the evolution times in chains of both two and three spins. In the case of a chain of two qubits, we derive conditions under which the associated four Bell states diagonalize the Hamiltonian. It is found that for the two Bell states 丨Ф＋） and 丨Ф-）, perfect mirroring does not occur （i.e. entanglement is not preserved under swapping）. On the other hand, perfect single qubit mirror effect （entanglement preservation） indeed occurs for the other two Bell states 丨ψ＋） and 丨ψ-） which are mapped into 丨Ф＋） and 丨Ф-） respectively. For the case of a chain of three qubits, the effects of a perfect single qubit mirroring on a set of four maximally entangled three qubit states ψl, ψ2, X1, and X2are studied. Due to the fact that quantum mirroring preserves maximal entanglement, the states ψ1 and ψ2 are not altered. However, quantum mirroring changes the states X1 and X2 only if we apply perfect quantum state mirroring in the site a = 1 of the three qubits spin chain. The above constrains the preservation of maximal entanglement under qubit mirroring of such a state. Due to the fact that swapping has already been experimentally tested, a posible, experimental implementations of single qubit mirroring is possible.展开更多
An increasing number of applications and functions are being introduced.into smartphones, but smartphones have limited computation ability and battery resources. To enhance smartphone capacity, cloud computing and vir...An increasing number of applications and functions are being introduced.into smartphones, but smartphones have limited computation ability and battery resources. To enhance smartphone capacity, cloud computing and virtualization techniques can be used to shift the workload from smartphone to computational infrastructure. In this paper, we propose a new framework in which a mirror is kept for each smartphone on a computing infrastructure in the telecom network. With mirrors, the workload can be greatly reduced, and smartphone resources can be virtually expanded. The feasibility of deploying this framework in telecom networks is demonstrated in the protocol design, a synchronization study, and a scalability test. Two applications are introduced to show how computational workload on the smartphone and traffic in the telecom network are signiScantly reduced using our techniques.展开更多
In the eyes of Croatian archaeologist Goran Durdevic,an ancient mirror can also reflect cultural exchanges along the ancient Silk Road.GORAN Durdevic,aged 35,is an archaeolo-gist from Croatia.Since 2013,following the ...In the eyes of Croatian archaeologist Goran Durdevic,an ancient mirror can also reflect cultural exchanges along the ancient Silk Road.GORAN Durdevic,aged 35,is an archaeolo-gist from Croatia.Since 2013,following the launch of the Belt and Road Initiative(BRI),there has been increasing cooperation between Chinese universities and those in B&R member countries.is entailed some Chinese universities expanding enrollment to include international students from those countries.In 2017,Goran,who was in Croatia at the time,saw the news of the enrollment and applied to study at the School of History at Capital Normal University in Beijing,China.During his six-year stay in China,he carried out comparative research on bronze mirrors from the Chinese Han Dynasty(206 BC-AD 220)and ancient Rome.When it comes to the Chinese and Western allusions pertaining to mirrors,Goran can name a list of ancient Chinese philosophies which are inspiring to him.“In the Tang Dynasty(618-907),people believed that by using copper as a mirror,one could check one’s physical appearance;by using people as a mirror,one could understand gains and losses;and by using history as a mirror,one could know the rise and fall of regimes.”展开更多
Due to the inability of manufacturing a single monolithic mirror at the 10-meter scales,segmented mirrors have become indispensable tools in modern astronomical research.However,to match the imaging performance of the...Due to the inability of manufacturing a single monolithic mirror at the 10-meter scales,segmented mirrors have become indispensable tools in modern astronomical research.However,to match the imaging performance of the monolithic counterpart,the sub-mirrors must maintain precise co-phasing.Piston error critically degrades segmented mirror imaging quality,necessitating efficient and precise detection.To ad-dress the limitations that the conventional circular-aperture diffraction with two-wavelength algorithm is sus-ceptible to decentration errors,and the traditional convolutional neural networks(CNNs)struggle to capture global features under large-range piston errors due to their restricted local receptive fields,this paper pro-poses a method that integrates extended Young’s interference principles with a Vision Transformer(ViT)to detect piston error.By suppressing decentration error interference through two symmetrically arranged aper-tures and extending the measurement range to±7.95μm via a two-wavelength(589 nm/600 nm)algorithm.This approach exploits ViT’s self-attention mechanism to model global characteristics of interference fringes.Unlike CNNs constrained by local convolutional kernels,the ViT significantly improves sensitivity to inter-ferogram periodicity.The simulation results demonstrate that the proposed method achieves a measurement accuracy of 5 nm(0.0083λ0)across the range of±7.95μm,while maintaining an accuracy exceeding 95%in the presence of Gaussian noise(SNR≥15 dB),Poisson noise(λ≥9 photons/pixel),and sub-mirror gap er-ror(Egap≤0.2)interference.Moreover,the detection speed shows significant improvement compared to the cross-correlation algorithm.This study establishes an accurate,robust framework for segmented mirror error detection,advancing high-precision astronomical observation.展开更多
The neutral surface of a concave thin mirror is too close to the mirror surface,which makes it difficult to effectively mount the flexible structure and increases the mirror surface shape error.To address this problem...The neutral surface of a concave thin mirror is too close to the mirror surface,which makes it difficult to effectively mount the flexible structure and increases the mirror surface shape error.To address this problem,we design a flexible support structure including connectors,a support plate,and flexible structures,and construct an equivalent mirror by installing connectors and a support plate on the back of the mirror.While ensuring that the neutral surface of the equivalent mirror is moved away from the mirror surface,we optimize the support structure so that the rotary center of the flexible structure is located on the neutral surface of the equivalent mirror,avoiding the tilting moment.Following design and modeling of the structure,we analyze the static and dynamic characteristics using a finite element simulation,finding a root-mean-square(RMS)value for the surface shape error of 9.28 nm under the coupled effects of 1g gravity load,4℃ temperature rise,and 0.005 mm unevenness assembly error,with a fundamental frequency of 170.75 Hz,which all meet the design requirements.Finally,we carry out a surface shape error test of the mirror assembly,confirming it to meet the design index requirement of the mirror assembly.Simulation and test results verify the reliability and effectiveness of our proposed support structure.展开更多
With the explosion of information nowadays, applying data storage safety requirements has become a new challenge, especially in high data available cluster environments. With the emergence of Storage Area Networks （S...With the explosion of information nowadays, applying data storage safety requirements has become a new challenge, especially in high data available cluster environments. With the emergence of Storage Area Networks （SANs）, storage can be network-based and consolidated, and mass data movements via Fiber Channels （FCs） can be of very high speed. Based on these features, this paper introduces a dual-node storage cluster designed for remote mirroring as a concurrent data replication method to protect data during system failures. This design takes full advantage of a SAN system＇s benefits, and it adopts a synchronous protocol to guarantee a fully up-to-date data copy on the remote site. By developing a Linux kernel module to control the I/O flow and by using the technologies of software Logic Unit Number （LUN） masking, background online resynchronization and a self-management daemon, we have achieved a reliable mirroring system with the characteristics of server-free data replication, fault tolerance, online disaster recovery and high performance. In this study, we implemented the design in a remote mirror subsystem built on a software Fiber Channel Storage Area Network （FC-SAN） system.展开更多
In deep drilling applications,such as those for geothermal energy,there are many challenges,such as those related to efficient operation of the drilling fluid(mud)pumping system.Legacy drilling rigs often use paired,p...In deep drilling applications,such as those for geothermal energy,there are many challenges,such as those related to efficient operation of the drilling fluid(mud)pumping system.Legacy drilling rigs often use paired,parallel-connected independent-excitation direct-current(DC)motors for mud pumps,that are supplied by a single power converter.This configuration results in electrical power imbalance,thus reducing its efficiency.This paper investigates this power imbalance issue in such legacy DC mud pump drive systems and offers an innovative solution in the form of a closed-loop control system for electrical load balancing.The paper first analyzes the drilling fluid circulation and electrical drive layout to develop an analytical model that can be used for electrical load balancing and related energy efficiency improvements.Based on this analysis,a feedback control system(so-called“current mirror”control system)is designed to balance the electrical load(i.e.,armature currents)of parallel-connected DC machines by adjusting the excitation current of one of the DC machines,thus mitigating the power imbalance of the electrical drive.Theproposed control systemeffectiveness has been validated,first through simulations,followed by experimental testing on a deep drilling rig during commissioning and field tests.The results demonstrate the practical viability of the proposed“current mirror”control system that can effectively and rather quickly equalize the armature currents of both DC machines in a parallel-connected electrical drive,and thus balance both the electrical and mechanical load of individual DC machines under realistic operating conditions of the mud pump electrical drive.展开更多
Adaptive optics(AO)has significantly advanced high-resolution solar observations by mitigating atmospheric turbulence.However,traditional post-focal AO systems suffer from external configurations that introduce excess...Adaptive optics(AO)has significantly advanced high-resolution solar observations by mitigating atmospheric turbulence.However,traditional post-focal AO systems suffer from external configurations that introduce excessive optical surfaces,reduced light throughput,and instrumental polarization.To address these limitations,we propose an embedded solar adaptive optics telescope(ESAOT)that intrinsically incorporates the solar AO(SAO)subsystem within the telescope's optical train,featuring a co-designed correction chain with a single Hartmann-Shack full-wavefront sensor(HS f-WFS)and a deformable secondary mirror(DSM).The HS f-WFS uses temporal-spatial hybrid sampling technique to simultane-ously resolve tip-tilt and high-order aberrations,while the DSM performs real-time compensation through adaptive modal optimization.This unified architecture achieves symmetrical polarization suppression and high system throughput by min-imizing optical surfaces.A 600 mm ESAOT prototype incorporating a 12×12 micro-lens array HS f-WFS and 61-actuator piezoelectric DSM has been developed and successfully conducted on-sky photospheric observations.Validations in-cluding turbulence simulations,optical bench testing,and practical observations at the Lijiang observatory collectively confirm the system's capability to maintain aboutλ/10 wavefront error during active region tracking.This architectural breakthrough of the ESAOT addresses long-standing SAO integration challenges in solar astronomy and provides scala-bility analyses confirming direct applicability to the existing and future large solar observation facilities.展开更多
To address the issues of peak overlap caused by complex matrices in agricultural product terahertz(THz)spectral signals and the dynamic,nonlinear interference induced by environmental and system noise,this study explo...To address the issues of peak overlap caused by complex matrices in agricultural product terahertz(THz)spectral signals and the dynamic,nonlinear interference induced by environmental and system noise,this study explores the feasibility of adaptive-signal-decomposition-based denoising methods to improve THz spectral quality.THz time-domain spectroscopy(THz-TDS)combined with an attenuated total reflection(ATR)accessory was used to collect THz absorbance spectra from 48 peanut samples.Taking the quantitative prediction model of peanut moisture content based on THz-ATR as an example,wavelet transform(WT),empirical mode decomposition(EMD),local mean decomposition(LMD),and its improved methods-segmented local mean decomposition(SLMD)and piecewise mirror extension local mean decomposition(PME-LMD)-were employed for spectral denoising.The applicability of different denoising methods was evaluated using a support vector regression(SVR)model.Experimental results show that the peanut moisture content prediction model constructed after PME-LMD denoising achieved the best performance,with a root mean square error(RMSE),coefficient of determination(R^(2)),and mean absolute percentage error(MAPE)of 0.010,0.912,and 0.040,respectively.Compared with traditional methods,PME-LMD significantly improved spectral quality and model prediction performance.The PME-LMD denoising strategy proposed in this study effectively suppresses non-uniform noise interference in THz spectral signals,providing an efficient and accurate preprocessing method for THz spectral analysis of agricultural products.This research provides theoretical support and technical guidance for the application of THz technology for detecting agricultural product quality.展开更多
Activity 1 Think about the following questions and write down your answers before reading the text.1.If you were asked to design a special reading space using mirrors,how do you think they might influence people's...Activity 1 Think about the following questions and write down your answers before reading the text.1.If you were asked to design a special reading space using mirrors,how do you think they might influence people's reading experience?2.Besides mirrors and special flooring,what other everyday objects or materials do you think could be used to create unique and interesting atmospheres in libraries?展开更多
I used to be such a shy boy that I even couldn’t give a speech in public or talk to strangers.But things have changed because of my Chinese teacher.Two years ago,my Chinese teacher asked me to share what I had learne...I used to be such a shy boy that I even couldn’t give a speech in public or talk to strangers.But things have changed because of my Chinese teacher.Two years ago,my Chinese teacher asked me to share what I had learned from the books.At first,I felt so nervous because it was my first time to speak in front of the class.When the teacher found it,she gave me lots of useful suggestions.For example,she encouraged me to keep clam and practice over and over again by talking to myself in the mirror.I followed her advice.To my surprise,the speech was a total success.展开更多
Empathy is one of the most important abilities for social animals.In a world that is largely socially constructed,when encountering altered affective states of others,particularly negative states,individuals often exh...Empathy is one of the most important abilities for social animals.In a world that is largely socially constructed,when encountering altered affective states of others,particularly negative states,individuals often exhibit evolutionarily conserved empathic behaviors,such as mirroring,consolation,and helping[l,2].Appropriate empathic behaviors can foster the consolidation of social relationships.Previous studies have suggested that both male and female rodents show some empathic behaviors when facing affective conspecifics[1].However,the role of sex in different empathic behaviors remains largely unexplored.Therefore,there is a need to probe whether animals show sex-dependent empathic behavior and which neural circuits modulate these distinct behaviors.展开更多
In the coldest time every year,when Puma Yumco Lake freezes into a giant blue mirror,villagers nearby at Dowa Village in Nakartse County would herd thousands of sheep across the iced lake surface to find better forage...In the coldest time every year,when Puma Yumco Lake freezes into a giant blue mirror,villagers nearby at Dowa Village in Nakartse County would herd thousands of sheep across the iced lake surface to find better forage on the mid-lake islands.Such herding practices have lasted for a thousand years.Sapphire blue,pure white of both sheep fur and snow on the mountaintops,all colors blend together in a perfect harmony.展开更多
In unconventional high-temperature(high-T_(c))superconductors,the pair density wave state,an exotic superconducting order showing spatially periodic order parameter modulations with the period of several unit cells an...In unconventional high-temperature(high-T_(c))superconductors,the pair density wave state,an exotic superconducting order showing spatially periodic order parameter modulations with the period of several unit cells and translational symmetry breaking,has attracted broad attention.However,the superconducting pair density modulation(PDM)within a single unit cell has never been carefully investigated before.Here,using scanning tunneling microscopy/spectroscopy,we report the observation of PDM in monolayer high-T_(c) iron chalcogenide films epitaxially grown on SrTiO_(3)(001).The superconductivity modulations are characterized by the superconducting gap size and the coherence peak sharpness.Further analysis shows that the local maxima and minima in the superconducting gap modulation are centered at the crystallographic locations of the chalcogen atoms,revealing the breaking of the glide-mirror symmetry of the chalcogen atoms in monolayer high-T_(c) iron chalcogenide films grown on SrTiO_(3)(001).Our findings provide precise microscopic information on superconductivity within the lattice unit cell and may promote the understanding of unconventional high-T_(c) superconductivity.展开更多
Animated block-buster Ne Zha2 is the first non-Hollywood movie to be part of the.top 10 list and is already the highest-grossing animated movie of all time.If Ne Zha 2 has a bigger international rollout,it will be int...Animated block-buster Ne Zha2 is the first non-Hollywood movie to be part of the.top 10 list and is already the highest-grossing animated movie of all time.If Ne Zha 2 has a bigger international rollout,it will be interesting to see how far its initial momentum can take it.展开更多
Polarization control and modulation of optical signals play a crucial role in optical information transmission,with widespread applications in optical communication,sensing,and signal processing.Here,we propose an int...Polarization control and modulation of optical signals play a crucial role in optical information transmission,with widespread applications in optical communication,sensing,and signal processing.Here,we propose an intrinsically chiral nano-kirigami metasurface featuring out-of-plane twisting,which enables switchable spinselective light transmission.At the operating wavelength,it nearly completely blocks the transmission of one type of circularly polarized light while maintaining a transmission exceeding 70%for the other type.Crucially,by merely adjusting the rotation angles or deformation heights of the four arms of the nano-kirigami structures,the metasurface can switch from selective transmission of left-handed circularly polarized light to right-handed circularly polarized light,and vice versa,without the need for dramatic structural geometric chirality changes through mirror operations.Simultaneously,a remarkable circular dichroism of up to 0.74 is achieved,and its sign reverses with the transition of transmission.Electromagnetic multipolar analysis reveals that this switching of chiral response is governed by handedness-dependent excitations of toroidal dipole modes.Additionally,the spin-encoded near-field imaging results demonstrate the potential applications of this switchable spin-selective transmission based on nano-kirigami metasurfaces in digital imaging and chiroptical encryption.展开更多
The isospin asymmetry and quadrupole deformation value of drip-line nuclei are investigated using the Weizsäcker-Skyrme nuclear mass formula.We observe that for heavy nuclei at the neutron drip line,the Coulomb e...The isospin asymmetry and quadrupole deformation value of drip-line nuclei are investigated using the Weizsäcker-Skyrme nuclear mass formula.We observe that for heavy nuclei at the neutron drip line,the Coulomb energy heightened by an aug-mented charge could not be mitigated completely by symmetry energy because of isospin asymmetry saturation but is resisted complementally by strong nuclear deformation.The positions of saltation for the difference in proton numbers between two neighboring nuclei at the neutron drip line,and the isospin asymmetry of the neutron drip-line nucleus as a function of the neutron number distinctly correspond to the known magic numbers,which can serve as a reference to verify the undeter-mined neutron magic number.Through fitting of the binding energy difference between mirror nuclei(BEDbMN),a set of Coulomb energy coefficients with greater accuracy is obtained.A high-precision description of the BEDbMN is useful for accurately determining the experimentally unknown mass of the nucleus close to the proton drip line if the mass of its mirror nucleus is measured experimentally.展开更多
We present a proof of the Strominger-Yau-Zaslow (SYZ) conjecture by demonstrating that mirror symmetry fundamentally represents an equivalence of computational structures between Calabi-Yau manifolds. Through developm...We present a proof of the Strominger-Yau-Zaslow (SYZ) conjecture by demonstrating that mirror symmetry fundamentally represents an equivalence of computational structures between Calabi-Yau manifolds. Through development of a rigorous quantum complexity operator formalism, we show that mirror pairs must have equivalent complexity spectra and that the SYZ fibration naturally preserves these computational invariants while implementing the required geometric transformations. Our proof proceeds by first establishing a precise mathematical framework connecting quantum complexity with geometric structures, then demonstrating that the special Lagrangian torus fibration preserves computational complexity at both local and global levels, and finally proving that this preservation necessarily implies the geometric correspondences required by the SYZ conjecture. This approach not only resolves the conjecture but reveals deeper insights about the relationship between computation and geometry in string theory. We introduce new complexity-based invariants for studying mirror symmetry and demonstrate how our framework extends naturally to related geometric structures.展开更多
文摘Perfect quantum state mirroring in a chain of N spins is defined as the condition in which the state 丨i 丨of the chain is swapped into the state 丨N - i丨 within a time evolution interval r. Such a phenomenon is an interesting way of transfering entanglement. An expressions for the perfect mirroring of a single qubit contained in a spin chain were proposed in the past. We exploit such an expressions for calculating the evolution times in chains of both two and three spins. In the case of a chain of two qubits, we derive conditions under which the associated four Bell states diagonalize the Hamiltonian. It is found that for the two Bell states 丨Ф＋） and 丨Ф-）, perfect mirroring does not occur （i.e. entanglement is not preserved under swapping）. On the other hand, perfect single qubit mirror effect （entanglement preservation） indeed occurs for the other two Bell states 丨ψ＋） and 丨ψ-） which are mapped into 丨Ф＋） and 丨Ф-） respectively. For the case of a chain of three qubits, the effects of a perfect single qubit mirroring on a set of four maximally entangled three qubit states ψl, ψ2, X1, and X2are studied. Due to the fact that quantum mirroring preserves maximal entanglement, the states ψ1 and ψ2 are not altered. However, quantum mirroring changes the states X1 and X2 only if we apply perfect quantum state mirroring in the site a = 1 of the three qubits spin chain. The above constrains the preservation of maximal entanglement under qubit mirroring of such a state. Due to the fact that swapping has already been experimentally tested, a posible, experimental implementations of single qubit mirroring is possible.
文摘An increasing number of applications and functions are being introduced.into smartphones, but smartphones have limited computation ability and battery resources. To enhance smartphone capacity, cloud computing and virtualization techniques can be used to shift the workload from smartphone to computational infrastructure. In this paper, we propose a new framework in which a mirror is kept for each smartphone on a computing infrastructure in the telecom network. With mirrors, the workload can be greatly reduced, and smartphone resources can be virtually expanded. The feasibility of deploying this framework in telecom networks is demonstrated in the protocol design, a synchronization study, and a scalability test. Two applications are introduced to show how computational workload on the smartphone and traffic in the telecom network are signiScantly reduced using our techniques.
文摘In the eyes of Croatian archaeologist Goran Durdevic,an ancient mirror can also reflect cultural exchanges along the ancient Silk Road.GORAN Durdevic,aged 35,is an archaeolo-gist from Croatia.Since 2013,following the launch of the Belt and Road Initiative(BRI),there has been increasing cooperation between Chinese universities and those in B&R member countries.is entailed some Chinese universities expanding enrollment to include international students from those countries.In 2017,Goran,who was in Croatia at the time,saw the news of the enrollment and applied to study at the School of History at Capital Normal University in Beijing,China.During his six-year stay in China,he carried out comparative research on bronze mirrors from the Chinese Han Dynasty(206 BC-AD 220)and ancient Rome.When it comes to the Chinese and Western allusions pertaining to mirrors,Goran can name a list of ancient Chinese philosophies which are inspiring to him.“In the Tang Dynasty(618-907),people believed that by using copper as a mirror,one could check one’s physical appearance;by using people as a mirror,one could understand gains and losses;and by using history as a mirror,one could know the rise and fall of regimes.”
文摘Due to the inability of manufacturing a single monolithic mirror at the 10-meter scales,segmented mirrors have become indispensable tools in modern astronomical research.However,to match the imaging performance of the monolithic counterpart,the sub-mirrors must maintain precise co-phasing.Piston error critically degrades segmented mirror imaging quality,necessitating efficient and precise detection.To ad-dress the limitations that the conventional circular-aperture diffraction with two-wavelength algorithm is sus-ceptible to decentration errors,and the traditional convolutional neural networks(CNNs)struggle to capture global features under large-range piston errors due to their restricted local receptive fields,this paper pro-poses a method that integrates extended Young’s interference principles with a Vision Transformer(ViT)to detect piston error.By suppressing decentration error interference through two symmetrically arranged aper-tures and extending the measurement range to±7.95μm via a two-wavelength(589 nm/600 nm)algorithm.This approach exploits ViT’s self-attention mechanism to model global characteristics of interference fringes.Unlike CNNs constrained by local convolutional kernels,the ViT significantly improves sensitivity to inter-ferogram periodicity.The simulation results demonstrate that the proposed method achieves a measurement accuracy of 5 nm(0.0083λ0)across the range of±7.95μm,while maintaining an accuracy exceeding 95%in the presence of Gaussian noise(SNR≥15 dB),Poisson noise(λ≥9 photons/pixel),and sub-mirror gap er-ror(Egap≤0.2)interference.Moreover,the detection speed shows significant improvement compared to the cross-correlation algorithm.This study establishes an accurate,robust framework for segmented mirror error detection,advancing high-precision astronomical observation.
基金supported by the National Natural Science Foundation of China(12473085).
文摘The neutral surface of a concave thin mirror is too close to the mirror surface,which makes it difficult to effectively mount the flexible structure and increases the mirror surface shape error.To address this problem,we design a flexible support structure including connectors,a support plate,and flexible structures,and construct an equivalent mirror by installing connectors and a support plate on the back of the mirror.While ensuring that the neutral surface of the equivalent mirror is moved away from the mirror surface,we optimize the support structure so that the rotary center of the flexible structure is located on the neutral surface of the equivalent mirror,avoiding the tilting moment.Following design and modeling of the structure,we analyze the static and dynamic characteristics using a finite element simulation,finding a root-mean-square(RMS)value for the surface shape error of 9.28 nm under the coupled effects of 1g gravity load,4℃ temperature rise,and 0.005 mm unevenness assembly error,with a fundamental frequency of 170.75 Hz,which all meet the design requirements.Finally,we carry out a surface shape error test of the mirror assembly,confirming it to meet the design index requirement of the mirror assembly.Simulation and test results verify the reliability and effectiveness of our proposed support structure.
基金This work is supported by the National Natural Science Foundation of China under Grant No.10576018the National Grand Fundamental Research 973 Program of China under Grant No.2004CB318205the Program for New Century Excellent Talents in University.
文摘With the explosion of information nowadays, applying data storage safety requirements has become a new challenge, especially in high data available cluster environments. With the emergence of Storage Area Networks （SANs）, storage can be network-based and consolidated, and mass data movements via Fiber Channels （FCs） can be of very high speed. Based on these features, this paper introduces a dual-node storage cluster designed for remote mirroring as a concurrent data replication method to protect data during system failures. This design takes full advantage of a SAN system＇s benefits, and it adopts a synchronous protocol to guarantee a fully up-to-date data copy on the remote site. By developing a Linux kernel module to control the I/O flow and by using the technologies of software Logic Unit Number （LUN） masking, background online resynchronization and a self-management daemon, we have achieved a reliable mirroring system with the characteristics of server-free data replication, fault tolerance, online disaster recovery and high performance. In this study, we implemented the design in a remote mirror subsystem built on a software Fiber Channel Storage Area Network （FC-SAN） system.
文摘In deep drilling applications,such as those for geothermal energy,there are many challenges,such as those related to efficient operation of the drilling fluid(mud)pumping system.Legacy drilling rigs often use paired,parallel-connected independent-excitation direct-current(DC)motors for mud pumps,that are supplied by a single power converter.This configuration results in electrical power imbalance,thus reducing its efficiency.This paper investigates this power imbalance issue in such legacy DC mud pump drive systems and offers an innovative solution in the form of a closed-loop control system for electrical load balancing.The paper first analyzes the drilling fluid circulation and electrical drive layout to develop an analytical model that can be used for electrical load balancing and related energy efficiency improvements.Based on this analysis,a feedback control system(so-called“current mirror”control system)is designed to balance the electrical load(i.e.,armature currents)of parallel-connected DC machines by adjusting the excitation current of one of the DC machines,thus mitigating the power imbalance of the electrical drive.Theproposed control systemeffectiveness has been validated,first through simulations,followed by experimental testing on a deep drilling rig during commissioning and field tests.The results demonstrate the practical viability of the proposed“current mirror”control system that can effectively and rather quickly equalize the armature currents of both DC machines in a parallel-connected electrical drive,and thus balance both the electrical and mechanical load of individual DC machines under realistic operating conditions of the mud pump electrical drive.
基金support from the National Science Foundation of China(NSFC)(Grants No.12293031 and No.61905252)the National Science Foundation for Distinguished Young Scholars(Grant No.12022308)the National Key R&D Program of China(Grants No.2021YFC2202200 and No.2021YFC2202204).
文摘Adaptive optics(AO)has significantly advanced high-resolution solar observations by mitigating atmospheric turbulence.However,traditional post-focal AO systems suffer from external configurations that introduce excessive optical surfaces,reduced light throughput,and instrumental polarization.To address these limitations,we propose an embedded solar adaptive optics telescope(ESAOT)that intrinsically incorporates the solar AO(SAO)subsystem within the telescope's optical train,featuring a co-designed correction chain with a single Hartmann-Shack full-wavefront sensor(HS f-WFS)and a deformable secondary mirror(DSM).The HS f-WFS uses temporal-spatial hybrid sampling technique to simultane-ously resolve tip-tilt and high-order aberrations,while the DSM performs real-time compensation through adaptive modal optimization.This unified architecture achieves symmetrical polarization suppression and high system throughput by min-imizing optical surfaces.A 600 mm ESAOT prototype incorporating a 12×12 micro-lens array HS f-WFS and 61-actuator piezoelectric DSM has been developed and successfully conducted on-sky photospheric observations.Validations in-cluding turbulence simulations,optical bench testing,and practical observations at the Lijiang observatory collectively confirm the system's capability to maintain aboutλ/10 wavefront error during active region tracking.This architectural breakthrough of the ESAOT addresses long-standing SAO integration challenges in solar astronomy and provides scala-bility analyses confirming direct applicability to the existing and future large solar observation facilities.
基金Supported by the National Key R&D Program of China(2023YFD2101001)National Natural Science Foundation of China(32202144,61807001)。
文摘To address the issues of peak overlap caused by complex matrices in agricultural product terahertz(THz)spectral signals and the dynamic,nonlinear interference induced by environmental and system noise,this study explores the feasibility of adaptive-signal-decomposition-based denoising methods to improve THz spectral quality.THz time-domain spectroscopy(THz-TDS)combined with an attenuated total reflection(ATR)accessory was used to collect THz absorbance spectra from 48 peanut samples.Taking the quantitative prediction model of peanut moisture content based on THz-ATR as an example,wavelet transform(WT),empirical mode decomposition(EMD),local mean decomposition(LMD),and its improved methods-segmented local mean decomposition(SLMD)and piecewise mirror extension local mean decomposition(PME-LMD)-were employed for spectral denoising.The applicability of different denoising methods was evaluated using a support vector regression(SVR)model.Experimental results show that the peanut moisture content prediction model constructed after PME-LMD denoising achieved the best performance,with a root mean square error(RMSE),coefficient of determination(R^(2)),and mean absolute percentage error(MAPE)of 0.010,0.912,and 0.040,respectively.Compared with traditional methods,PME-LMD significantly improved spectral quality and model prediction performance.The PME-LMD denoising strategy proposed in this study effectively suppresses non-uniform noise interference in THz spectral signals,providing an efficient and accurate preprocessing method for THz spectral analysis of agricultural products.This research provides theoretical support and technical guidance for the application of THz technology for detecting agricultural product quality.
文摘Activity 1 Think about the following questions and write down your answers before reading the text.1.If you were asked to design a special reading space using mirrors,how do you think they might influence people's reading experience?2.Besides mirrors and special flooring,what other everyday objects or materials do you think could be used to create unique and interesting atmospheres in libraries?
文摘I used to be such a shy boy that I even couldn’t give a speech in public or talk to strangers.But things have changed because of my Chinese teacher.Two years ago,my Chinese teacher asked me to share what I had learned from the books.At first,I felt so nervous because it was my first time to speak in front of the class.When the teacher found it,she gave me lots of useful suggestions.For example,she encouraged me to keep clam and practice over and over again by talking to myself in the mirror.I followed her advice.To my surprise,the speech was a total success.
基金supported by grants from the National Natural Science Foundation of China(32125018 and 32071005)the National Key Research and Development Program of China(2021YFA1101701)+5 种基金Zhejiang Provincial Natural Science Foundation of China(LD24H090002)the Nanhu Brain-computer Interface Institute(010904008)the Fundamental Research Funds for the Central Universities(226-2024-00133)the Key R&D Program of Zhejiang(2024SSYS0016)the Non-profit Central Research Institute Fund of the Chinese Academy of Medical Sciences(2023-PT310-01)the MOE Frontiers Science Center for Brain Science&Brain-Machine Integration of Zhejiang University.
文摘Empathy is one of the most important abilities for social animals.In a world that is largely socially constructed,when encountering altered affective states of others,particularly negative states,individuals often exhibit evolutionarily conserved empathic behaviors,such as mirroring,consolation,and helping[l,2].Appropriate empathic behaviors can foster the consolidation of social relationships.Previous studies have suggested that both male and female rodents show some empathic behaviors when facing affective conspecifics[1].However,the role of sex in different empathic behaviors remains largely unexplored.Therefore,there is a need to probe whether animals show sex-dependent empathic behavior and which neural circuits modulate these distinct behaviors.
文摘In the coldest time every year,when Puma Yumco Lake freezes into a giant blue mirror,villagers nearby at Dowa Village in Nakartse County would herd thousands of sheep across the iced lake surface to find better forage on the mid-lake islands.Such herding practices have lasted for a thousand years.Sapphire blue,pure white of both sheep fur and snow on the mountaintops,all colors blend together in a perfect harmony.
基金supported by the National Natural Science Foundation of China(Grant Nos.12488201 and 12404215)the Innovation Program for Quantum Science and Technology(Grant No.2021ZD0302403)+1 种基金Guangdong Provincial Quantum Science Strategic Initiative(Grant Nos.GDZX2401001 and GDZX2401009)supported by the U.S.Department of Energy,Basic Energy Sciences(Grant No.DE-FG02-99ER45747)。
文摘In unconventional high-temperature(high-T_(c))superconductors,the pair density wave state,an exotic superconducting order showing spatially periodic order parameter modulations with the period of several unit cells and translational symmetry breaking,has attracted broad attention.However,the superconducting pair density modulation(PDM)within a single unit cell has never been carefully investigated before.Here,using scanning tunneling microscopy/spectroscopy,we report the observation of PDM in monolayer high-T_(c) iron chalcogenide films epitaxially grown on SrTiO_(3)(001).The superconductivity modulations are characterized by the superconducting gap size and the coherence peak sharpness.Further analysis shows that the local maxima and minima in the superconducting gap modulation are centered at the crystallographic locations of the chalcogen atoms,revealing the breaking of the glide-mirror symmetry of the chalcogen atoms in monolayer high-T_(c) iron chalcogenide films grown on SrTiO_(3)(001).Our findings provide precise microscopic information on superconductivity within the lattice unit cell and may promote the understanding of unconventional high-T_(c) superconductivity.
文摘Animated block-buster Ne Zha2 is the first non-Hollywood movie to be part of the.top 10 list and is already the highest-grossing animated movie of all time.If Ne Zha 2 has a bigger international rollout,it will be interesting to see how far its initial momentum can take it.
基金supported by the National Natural Science Foundation of China(Grant Nos.62205282 and 12074331)the Hebei Natural Science Foundation(Grant No.A2022203035)the Science and Technology Project of Hebei Education Department(Grant No.BJK2023009)。
文摘Polarization control and modulation of optical signals play a crucial role in optical information transmission,with widespread applications in optical communication,sensing,and signal processing.Here,we propose an intrinsically chiral nano-kirigami metasurface featuring out-of-plane twisting,which enables switchable spinselective light transmission.At the operating wavelength,it nearly completely blocks the transmission of one type of circularly polarized light while maintaining a transmission exceeding 70%for the other type.Crucially,by merely adjusting the rotation angles or deformation heights of the four arms of the nano-kirigami structures,the metasurface can switch from selective transmission of left-handed circularly polarized light to right-handed circularly polarized light,and vice versa,without the need for dramatic structural geometric chirality changes through mirror operations.Simultaneously,a remarkable circular dichroism of up to 0.74 is achieved,and its sign reverses with the transition of transmission.Electromagnetic multipolar analysis reveals that this switching of chiral response is governed by handedness-dependent excitations of toroidal dipole modes.Additionally,the spin-encoded near-field imaging results demonstrate the potential applications of this switchable spin-selective transmission based on nano-kirigami metasurfaces in digital imaging and chiroptical encryption.
基金supported by the Ministry of Science and Technology of China(No.2022YFE0103400)Natural Science Foundation of Guangxi Province(No.2021GXNSFAA196052)National Natural Science Foundation of China(No.11965004).
文摘The isospin asymmetry and quadrupole deformation value of drip-line nuclei are investigated using the Weizsäcker-Skyrme nuclear mass formula.We observe that for heavy nuclei at the neutron drip line,the Coulomb energy heightened by an aug-mented charge could not be mitigated completely by symmetry energy because of isospin asymmetry saturation but is resisted complementally by strong nuclear deformation.The positions of saltation for the difference in proton numbers between two neighboring nuclei at the neutron drip line,and the isospin asymmetry of the neutron drip-line nucleus as a function of the neutron number distinctly correspond to the known magic numbers,which can serve as a reference to verify the undeter-mined neutron magic number.Through fitting of the binding energy difference between mirror nuclei(BEDbMN),a set of Coulomb energy coefficients with greater accuracy is obtained.A high-precision description of the BEDbMN is useful for accurately determining the experimentally unknown mass of the nucleus close to the proton drip line if the mass of its mirror nucleus is measured experimentally.
文摘We present a proof of the Strominger-Yau-Zaslow (SYZ) conjecture by demonstrating that mirror symmetry fundamentally represents an equivalence of computational structures between Calabi-Yau manifolds. Through development of a rigorous quantum complexity operator formalism, we show that mirror pairs must have equivalent complexity spectra and that the SYZ fibration naturally preserves these computational invariants while implementing the required geometric transformations. Our proof proceeds by first establishing a precise mathematical framework connecting quantum complexity with geometric structures, then demonstrating that the special Lagrangian torus fibration preserves computational complexity at both local and global levels, and finally proving that this preservation necessarily implies the geometric correspondences required by the SYZ conjecture. This approach not only resolves the conjecture but reveals deeper insights about the relationship between computation and geometry in string theory. We introduce new complexity-based invariants for studying mirror symmetry and demonstrate how our framework extends naturally to related geometric structures.
