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A buffer overflow detection and defense method based on RiSC-V instruction set extension

Cybersecurity 2024年第2期7卷 28-43页

作者： Chang Liu Yan-Jun Wu Jing-Zheng Wu Chen Zhao Intelligent Software research Center Institute of SoftwareChinese Academy of SciencesBejingChina University of Chinese Academy of Sciences BeijingChina State Key Laboratory of Computer Science Institute of SoftwareChinese Academy of SciencesBeijingChina

Buffer overflow poses a serious threat to the memory security of modern operating *** overwrites the con-tents of other memory areas by breaking through the buffer capacity limit,destroys the system execution environ-ment,and provides implementation space for various system attacks such as program control flow *** makes it a wide range of harms.A variety of security technologies have been proposed to deal with system security problems including buffer *** example,No eXecute(NX for short)is a memory management technology commonly used in Harvard *** can refuse the execution of code which residing in a specific memory,and can effectively suppress the abnormal impact of buffer overflow on control ***,in recent years,it has also been used in the field of system security,deriving a series of solutions based on NX technology,such as ExecShield,DEP,StackGuard,***,these security solutions often rely too much on the processor archi-tecture so that the protection coverage is insufficient and the accuracy is *** in the emerging system architecture field represented by RiSC-V,there is still a lack of effective solutions for buffer overflow *** the continuous rapid development of the system architecture,it is urgent to develop defense methods that are applicable to different system application environments and oriented to all executable memory spaces to meet the needs of system security ***,we propose BOP,A new system memory security design method based on RISC-V extended instructions,to build a RISC-V buffer overflow detection and defense system and deal with the buffer overflow threat in *** to this method,NX technology can be combined with program control flow analysis,and Nx bit mechanism can be used to manage the executability of memory space,so as to achieve a more granular detection and defense of buffer overflow attacks that may occur in RISC-V system

关键词： RISc-V Operating system security Buffer overflow Control flow hijacking Nx bit Xibop

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Wafer-scale carbon-based CMOS PDK compatible with siliconbased VLSI design flow

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Nano research 2024年第8期17卷 7557-7566页

作者： Minghui Yin Haitao Xu Yunxia You Ningfei Gao Weihua Zhang Hongwei Liu Huanhuan Zhou Chen Wang Lian-Mao Peng Zhiqiang Li Institute of Microelectronics Chinese Academy of SciencesBeijing 100029China University of Chinese Academy of Sciences Beijing 100049China State Key Lab of Fabrication Technologies for Integrated Circuits Beijing 100029China Beijing Hua Tan Yuan Xin Electronics Technology Co. Ltd.Beijing 101399China Institute of Carbon-based Thin Film Electronics Peking UniversityShanxi 030012China Key Laboratory for the Physics and Chemistry of Nanodevices and Center for Carbon-based Electronics School of ElectronicsPeking UniversityBeijing 100871China

Carbon nanotube field-effect transistors(CNTFETs)are increasingly recognized as a viable option for creating high-performance,low-power,and densely integrated circuits(ICs).Advancements in carbon-based electronics,encompassing materials and device technology,have enabled the fabrication of circuits with over 1000 gates,marking carbon-based integrated circuit design as a burgeoning field of research.A critical challenge in the realm of carbon-based very-large-scale integration(VLSI)is the lack of suitable automated design methodologies and infrastructure *** this study,we present the development of a waferscale 3μm carbon-based complementary metal-oxide-semiconductor(CMOS)process design kit(PDK)(3μm-CNTFETs-PDK)compatible with silicon-based Electronic Design Automation(EDA)tools and VLSI circuit design *** proposed 3μm-CNTFETs-PDK features a contacted gate pitch(CGP)of 21μm,a gate density of 128 gates/mm^(2),and a transistor density of 554 transistors/mm^(2),with an intrinsic gate delay around 134 *** of the 3μm-CNTFETs-PDK was achieved through the successful design and tape-out of 153 standard cells and 333-stage ring oscillator *** the carbon-based PDK and a silicon-based design platform,we successfully implemented a complete 64-bit static random-access memory(SRAM)circuit system for the first time,which exhibited timing,power,and area characteristics of clock@10 kHz,122.1μW,3795μm×2810μ*** research confirms that carbon-based IC design can be compatible with existing EDA tools and silicon-based VLSI design flow,thereby laying the groundwork for future carbon-based VLSI advancements.

关键词： carbon nanotube field-effect transistors(CNTFETs) complementary metal-oxide-semiconductor(CMOS) process design kit(PDK) wafer-scale very-large-scale integration(VLSI)

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Unveiling the in-plane anisotropic dielectric waveguide modes in α-MoO_(3) flakes

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Chinese Physics B 2024年第7期33卷 631-636页

作者：廖莹陈佳宁 Beijing National Laboratory for Condensed Matter Physics Institute of PhysicsChinese Academy of SciencesBeijing 100190China School of Physical Sciences University of Chinese Academy of SciencesBeijing 100049China Songshan Lake Materials Laboratory Dongguan 523808China

The unique in-plane and out-of-plane anisotropy of α-MoO_(3) has attracted considerable interest with regard to potential optoelectronic applications. However, most research has focused on the mid-infrared spectrum, leaving its properties and applications in the visible and near-infrared light spectrum less explored. This study advances the understanding of waveguiding properties of α-MoO_(3) by near-field imaging of the waveguide modes along the [100] and [001] directions of α-MoO_(3) flakes at 633 nm and 785 nm. We investigate the effects of flake thickness and documented the modes' dispersion relationships, which is crucial for tailoring the optical responses of α-MoO_(3) in device applications. Our findings enhance the field of research into α-MoO_(3), highlighting its utility in fabricating next-generation optoelectronic devices due to its unique optically anisotropic waveguide.

关键词： waveguide anisotropic materials near-field imaging van der Waals materials

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Method to measure tree-ring width,density,elemental composition,and stable carbon and oxygen isotopes using one sample

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Journal of Forestry research 2024年第3期35卷 167-174页

作者： Chenxi Xu Yaru Zhao Wenling An Qingyu Zhao Yucheng Liu Masaki Sano Takeshi Nakatsuka Key Laboratory of Cenozoic Geology and Environment Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029People's Republic of China cas Center for Excellence in Life and Paleoenvironment Beijing 100044People's Republic of China College of Earth Sciences University of Chinese Academy of SciencesBeijing 100049People's Republic of China Graduate School of Environment Studies Nagoya UniversityNagoya 4648601Japan

Tree-ring width(RW),density,elemental com-position,and stable carbon and oxygen isotope(δ^(13)C,δ^(18)O)are widely used as proxies to assess climate change,ecology,and environmental pollution;however,a specific pretreat-ment has been needed for each ***,we developed a method by which each proxy can be measured in the same ***,the sample is polished for ring width *** obtaining the ring width data,the sample is cut to form a 1-mm-thick wood *** sample is then mounted in a vertical sample holder,and gradually scanned by an X-ray ***,the count rates of the fluorescent photons of elements(for chemical characteriza-tion)and a radiographic grayscale image(for wood density)are obtained,*** density and the element content are ***,cellulose is isolated from the 1-mm wood plate by removal of lignin,and *** producing this cellulose plate,cellulose subsamples are separated by knife under the microscope for inter-annual and intra-annual stable carbon and oxygen isotope(δ^(13)C,δ^(18)O)*** on this method,RW,density,elemental composition,δ^(13)C,and δ^(18)O can be measured from the same sample,which reduces sample amount and treatment time,and is helpful for multi-proxy comparison and combination research.

关键词： Tree-ring width Tree-ring density Tree-ring elemental composition Tree-ring stable carbon and oxygenisotopes

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Ultrafast Carrier Dynamics in Ba_(6)Cr_(2)S_(10)Modified by Toroidal Magnetic Phase Transition

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Chinese Physics Letters 2024年第4期41卷 164-172页

作者：姜丽桐姜聪颖田义超赵惠张俊田珍耘付少华梁二军望贤成靳常青赵继民 Beijing National Laboratory for Condensed Matter Physics Institute of PhysicsChinese Academy of SciencesBeijing 100190China School of Physical Sciences University of Chinese Academy of SciencesBeijing 100049China Strong-Field and Ultrafast Photonics Lab Institute of Laser EngineeringBeijing University of TechnologyBeijing 100124China School of Physics&Laboratory of Zhongyuan Light Zhengzhou UniversityZhengzhou 450052China Songshan Lake Materials Laboratory Dongguan 523808China

Ba_(6)Cr_(2)S_(10)is a recently discovered magnetic material,in which the spins are aligned ferromagnetically in the ab-plane and anti-parallelly in a paired form along the *** is characterized as a quasi-one dimensional(1D)dimerized structure with a ferrotoroidic order,forming the simplest candidate toroidal magnetic(TM)order and exhibiting an anti-ferromagnetic-like transition at around 10 ***-resolved ultrafast dynamics investigation of the novel A-Cr-S(A:metal elements)family of quantum materials has rarely been ***,we investigate the time-resolved pump-probe ultrafast dynamics of a Ba6Cr2S10 single crystal.A prominent change in the photo-excited carrier dynamics is observed at T_(c)=10 K,corresponding to the reported TM-paramagnetic phase transition.A potential unknown magnetic transition is also found at T^(*)=29 *** results provide new evidence for the TM magnetic transition in Ba_(6)Cr_(2)S_(10),and shed light on phase transitions in TM quantum materials.

关键词： ferromagnetic magnetic transition

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Dynamic adaptive spatio-temporal graph network for COVID-19 forecasting

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CAAI Transactions on Intelligence Technology 2024年第3期9卷 769-786页

作者： Xiaojun Pu Jiaqi Zhu Yunkun Wu Chang Leng Zitong Bo Hongan Wang Institute of Software Chinese Academy of Sciences BeijingChina Ecovacs Robotics Co. Ltd.SuzhouJiangsuChina Automotive Software Innovation Center ChongqingChina

Appropriately characterising the mixed space-time relations of the contagion process caused by hybrid space and time factors remains the primary challenge in COVID-19 ***,in previous deep learning models for epidemic forecasting,spatial and temporal variations are captured separately.A unified model is developed to cover all spatio-temporal ***,this measure is insufficient for modelling the complex spatio-temporal relations of infectious disease transmission.A dynamic adaptive spatio-temporal graph network(DASTGN)is proposed based on attention mechanisms to improve prediction *** DASTGN,complex spatio-temporal relations are depicted by adaptively fusing the mixed space-time effects and dynamic space-time dependency *** dual-scale model considers the time-specific,space-specific,and direct effects of the propagation process at the fine-grained ***,the model characterises impacts from various space-time neighbour blocks under time-varying interventions at the coarse-grained *** performance comparisons on the three COVID-19 datasets reveal that DASTGN achieves state-of-the-art results with a maximum improvement of 17.092%in the root mean-square error and 11.563%in the mean absolute *** results indicate that the mechanisms of designing DASTGN can effectively detect some spreading characteristics of *** spatio-temporal weight matrices learned in each proposed module reveal diffusion patterns in various *** conclusion,DASTGN has successfully captured the dynamic spatio-temporal variations of COVID-19,and considering multiple dynamic space-time relationships is essential in epidemic forecasting.

关键词： adaptive COVID-19 forecasting dynamic intervention spatio-temporal graph neural networks

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Bias distribution and regulation in photoelectrochemical overall water-splitting cells

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National Science Review 2024年第4期11卷 141-150页

作者： Kun Dang Siqin Liu Lei Wu Daojian Tang Jing Xue Jiaming Wang Hongwei Ji Chuncheng Chen Yuchao Zhang Jincai Zhao Key Laboratory of Photochemistry CAS ResearchEducation Center for Excellence in Molecular Sciences Institute of Chemistry Chinese Academy of Sciences University of Chinese Academy of Sciences

The water oxidation half-reaction at anodes is always considered the rate-limiting step of overall water splitting（OWS）,but the actual bias distribution between photoanodes and cathodes of photoelectro chemical（PEC） OWS cells has not been investigated *** this work,we find that,for PEC cells consisting of photoanodes（nickel-modified n-Si [Ni/n-Si] and α-Fe2O3） with low photovoltage(Vph 1V,the bias required for cathode activation can be significantly reduced,exhibiting a kinetics-controlled *** investigations show that the bias distribution can be regulated by tuning the electrolyte pH and using alternative half-reaction ***,a volcano plot is presented for the rational design of the overall reactions and unbiased PEC *** by this,an unbiased PEC cell consisting of a simple Ni/n-Si photoanode and Pt cathode is assembled,delivering a photo current density of 5.3±0.2 mA cm-2.

关键词： photoelectrochemistry overall reaction cell bias distribution photoanode water splitting

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Detector performance of the Gamma-ray Transient Monitor onboard DRO-A satellite

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Science China(Physics,Mechanics & Astronomy) 2024年第11期Mechanics & Astronomy) .卷 79-94页

作者： Pei-Yi Feng Zheng-Hua An Da-Li Zhang Chen-Wei Wang Chao Zheng Sheng Yang Shao-Lin Xiong Jia-Cong Liu Xin-Qiao Li Ke Gong Xiao-Jing Liu Min Gao Xiang-Yang Wen Ya-Qing Liu Xiao-Yun Zhao Fan Zhang Xi-Lei Sun Hong Lu Key Laboratory of Particle Astrophysics Institute of High Energy Physics Chinese Academy of Sciences University of Chinese Academy of Sciences State Key Laboratory of Particle Detection and Electronics Institute of High Energy Physics Chinese Academy of Sciences

The Gamma-ray Transient Monitor(GTM) is an all-sky monitor onboard the Distant Retrograde Orbit-A(DRO-A) satellite with the scientific objective of detecting gamma-ray transients ranging from 20 ke V to 1 MeV. The GTM was equipped with five Gamma-ray Transient Probe(GTP) detector modules utilizing a NaI(Tl) scintillator coupled with a SiPM array. To reduce the SiPM noise, GTP uses a dedicated dual-channel coincident readout design. In this work, we first studied the impact of different coincidence times on the detection efficiency and ultimately selected a 0.5 μs time coincidence window for offline data processing. To test the performance of the GTPs and validate the Monte-Carlo-simulated energy response, we conducted comprehensive ground calibration tests using the Hard X-ray Calibration Facility(HXCF) and radioactive sources, including the energy response, detection efficiency, spatial response, bias-voltage response, and temperature dependence. We extensively present the ground calibration results and validate the design and mass model of the GTP detector, thus providing the foundation for in-flight observations and scientific data analysis.

关键词： NaI(Tl) detector energy response ground calibration gamma-ray detector DRO-A satellite

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Contrasts of bimodal tropical instability waves(TIWs)-induced wind stress perturbations in the Pacific Ocean among observations,ocean models,and coupled climate models

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Journal of Oceanology and Limnology 2024年第1期42卷 1-23页

作者： Kai MA Chuanyu LIU Junli XU Fan WANG School of Mathematics and Physics Research Institute for Mathematics and Interdisciplinary SciencesQingdao University of Science and TechnologyQingdao 266100China Key Laboratory of Ocean Circulation and Waves Institute of OceanologyChinese Academy of SciencesQingdao 266071China Pilot National Laboratory for Marine Science and Technology(Qingdao) Qingdao 266237China

The coupling between wind stress perturbations and sea surface temperature(SST)perturbations induced by tropical instability waves(TIWs)in the Pacific Ocean has been revealed previously and proven crucial to both the atmosphere and ***,an overlooked fact by previous studies is that the loosely defined“TIWs”actually consist of two modes,including the Yanai wave-based TIW on the equator(hereafter eTIW)and the Rossby wave-based TIW off the equator(hereafter vTIW).Hence,the individual feedbacks of the wind stress to the bimodal TIWs remain *** this study,individual coupling relationships are established for both eTIW and v TIW,including the relationship between the TIW-induced SST perturbations and two components of wind stress perturbations,and the relationship between the TIW-induced wind stress perturbation divergence(curl)and the downwind(crosswind)TIW-induced SST *** show that,due to different distributions of eTIW and vTIW,the coupling strength induced by the eTIW is stronger on the equator,and that by the vTIW is stronger off the *** results of any of eTIW and vTIW are higher than those of the loosely defined *** further investigated how well the coupling relationships remained in several widely recognized oceanic general circulation models and fully coupled climate ***,the coupling relationships cannot be well represented in most numerical ***,we confirmed that higher resolution usually corresponds to more accurate ***,the coupling models established in this study are complementary to previous research and can be used to refine the oceanic and coupled climate models.

关键词： bimodal tropical instability waves mesoscale air-sea interaction coupled models Yanai wave

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Promoted surface charge density from interlayer Zn–N_(4) configuration in carbon nitride for enhanced CO_(2) photoreduction

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Nano research 2024年第4期17卷 2400-2409页

作者： Xianjin Shi Yu Huang Gangqiang Zhu Wei Peng Meijuan Chen State Key Laboratory of Loess and Quaternary Geology(SKLLQG) Key Laboratory of Aerosol Chemistry and PhysicsInstitute of Earth EnvironmentChinese Academy of SciencesXi’an 710061China Center of Excellence in Quaternary Science and Global Change Chinese Academy of SciencesXi’an 710061China University of Chinese Academy of Sciences Beijing 100049China School of Physics and Information Technology Shaanxi Normal UniversityXi’an 710062China School of Human Settlements and Civil Engineering Xi’an Jiaotong UniversityXi’an 710049China

The solar-driven reduction of CO_(2) into valuable products is a promising method to alleviate global environmental problems and energy ***,the low surface charge density limits the photocatalytic conversion performance of CO_(2).Herein,a polymeric carbon nitride(PCN)photocatalyst with Zn single atoms(Zn1/CN)was designed and synthesized for CO_(2) *** results of the CO_(2) photoreduction studies show that the CO and CH_(4) yields of Zn1/CN increased fivefold,reaching 76.9 and 22.9μmol/(g·h),respectively,in contrast to the unmodified ***+plasma-etched X-ray photoelectron spectroscopy and synchrotron radiation-based X-ray absorption fine structure results reveal that Zn single atom is mainly present in the interlayer space of PCN in the Zn–N_(4) *** characterizations indicate that the interlayer Zn–N_(4) configuration can amplify light absorption and establish an interlayer charge transfer ***-assisted Kelvin probe force microscopy confirms that more photogenerated electrons are delivered to the catalyst surface through interlayer Zn–N_(4) configuration,which increases its surface charge ***,in-situ infrared spectroscopy combined with density functional theory calculation reveals that promoted surface charge density accelerates key intermediates(*COOH)conversion,thus achieving efficient CO_(2) *** work elucidates the role of internal single atoms in catalytic surface reactions,which provides important implications for the design of single-atom catalysts.

关键词： single-atom catalysts photocatalytic CO_(2)reduction interlayer modification charge transfer dynamics surface charge density

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