摘要：Resistive Random Access Memory(ReRAM)-based neural network accelerators have potential to surpass their digital counterparts in computational efficiency and ***,design of these accelerators faces a number of challenges including imperfections of the Re RAM device and a large amount of calculations required to accurately simulate the *** present XB-SIM,a simulation framework for Re RAM-crossbar-based Convolutional Neural Network(CNN)***-SIM can be flexibly configured to simulate the accelerator’s structure and clock-driven behaviors at the architecture *** framework also includes an Re RAM-aware Neural Network(NN)training algorithm and a CNN-oriented mapper to train an NN and map it onto the simulated design *** of the simulator has been verified by the corresponding circuit simulation of a real ***,a batch processing mode of the massive calculations that are required to mimic the behavior of Re RAM-crossbar circuits is proposed to fully apply the computational concurrency of the mapping *** CPU/GPGPU,this batch processing mode can improve the simulation speed by up to 5.02 or *** this framework,comprehensive architectural exploration and end-to-end evaluation have been achieved,which provide some insights for systemic optimization.

摘要：Convolutional Neural Networks(CNNs)are widely used in computer vision,natural language processing,and so on,which generally require low power and high efficiency in real ***,energy efficiency has become a critical indicator of CNN *** that asynchronous circuits have the advantages of low power consumption,high speed,and no clock distribution problems,we design and implement an energy-efficient asynchronous CNN accelerator with a 65 nm Complementary Metal Oxide Semiconductor(CMOS)*** the absence of a commercial design tool flow for asynchronous circuits,we develop a novel design flow to implement Click-based asynchronous bundled data circuits efficiently to mask layout with conventional Electronic Design Automation(EDA)*** also introduce an adaptive delay matching method and perform accurate static timing analysis for the circuits to ensure correct *** accelerator for handwriting recognition network(LeNet-5 model)is *** test results show that the asynchronous accelerator has 30%less power in computing array than the synchronous one and that the energy efficiency of the asynchronous accelerator achieves 1.538 TOPS/W,which is 12%higher than that of the synchronous chip.

摘要：Compared with traditional solid-state drives(SSDs),open-channel SSDs(OCSSDs)expose their internal physical layout and provide a host-based flash translation layer(FTL)that allows host-side software to control the internal operations such as garbage collection(GC)and input/output(I/O)*** this paper,we comprehensively survey research works built on OCSSDs in recent *** show how they leverage the features of OCSSDs to achieve high throughput,low latency,long lifetime,strong performance isolation,and high resource *** categorize these efforts into five groups based on their optimization methods:adaptive interface customizing,rich FTL co-designing,internal parallelism exploiting,rational I/O scheduling,and efficient GC *** discuss the strengths and weaknesses of these efforts and find that almost all these efforts face a dilemma between performance effectiveness and management *** hope that this survey can provide fundamental knowledge to researchers who want to enter this field and further inspire new ideas for the development of OCSSDs.

摘要：This article evaluates the performance of 20 Coupled Model Intercomparison Project phase 6(CMIP6)models in simulating temperature and precipitation over China through comparisons with gridded observation data for the period of 1995–2014,with a focus on spatial patterns and interannual *** evaluations show that the CMIP6 models perform well in reproducing the climatological spatial distribution of temperature and precipitation,with better performance for temperature than for *** interannual variability can also be reasonably captured by most models,however,poor performance is noted regarding the interannual variability of winter *** on the comprehensive performance for the above two factors,the“highest-ranked”models are selected as an ensemble(BMME).The BMME outperforms the ensemble of all models(AMME)in simulating annual and winter temperature and precipitation,particularly for those subregions with complex terrain but it shows little improvement for summer temperature and *** AMME and BMME projections indicate annual increases for both temperature and precipitation across China by the end of the 21st century,with larger increases under the scenario of the Shared Socioeconomic Pathway 5/Representative Concentration Pathway 8.5(SSP585)than under scenario of the Shared Socioeconomic Pathway 2/Representative Concentration Pathway 4.5(SSP245).The greatest increases of annual temperature are projected for higher latitudes and higher elevations and the largest percentage-based increases in annual precipitation are projected to occur in northern and western China,especially under ***,the BMME,which generally performs better in these regions,projects lower changes in annual temperature and larger variations in annual precipitation when compared to the AMME projections.

摘要：由非平衡驱动的热传导通过物理接触传递内部的热能.描述热传导的数学方程是一个典型的偏微分方程.它广泛存在于各种工程问题中,例如粒子扩散、航天器设计和稀释制冷机运行.本文提出了一种显著优于经典算法的热传导量子算法,并在量子硬件上演示了热传导过程.作者通过一个辅助量子比特构造的对称系统来表示原始热传导系统,使得量子线路的复杂度减少到离散格点数量的对数多项式量级.与现有的基于Harrow-Hassidim-Lloyd的线性方程算法相比,本文的方法直接演化线性过程,不进行相位估计,避免相位估计涉及复杂的量子门操作和较大的输出误差,便于在目前的量子硬件实现,显示了该算法是实验友好特性.并且,作者在核自旋量子处理器上实现了两端恒温和绝热条件的一维热传导过程,温度的时空分布与理论预言很好的吻合.该算法可以自然地应用于可归约为热方程的物理过程.

摘要：Quantum secure direct communication(QSDC)attracts much attention for it can transmit secret messages directly without sharing a *** this article,we propose a one-step QSDC protocol,which only requires to distribute polarization-spatial-mode hyperentanglement for one *** this QSDC protocol,the eavesdropper cannot obtain any message,so that this protocol is unconditionally secure in *** protocol is a two-way quantum communication and has high capacity for it can transmit two bits of secret messages with one pair of *** entanglement fidelities of both polarization and spatial-mode degrees of freedom being 0.98,the maximal communication distance of this onestep QSDC can reach about 216 *** can also be used to generate the *** this regard,the key generation rate is estimated about 2.5 times of that in the entanglement-based QKD with the communication distance of 150 *** the help of future quantum repeaters,this QSDC protocol can provide unconditionally secure communication over arbitrarily long distance.

摘要：叉指式背接触硅异质结(IBC-SHJ)太阳电池由于其优异的光学性能备受关注,但是较低的填充因子(FF)限制了其转换效率.本文中,我们用Silvaco TCAD软件模拟了IBC-SHJ太阳电池,发现p-n结和高低结收集载流子的能力有很大差异.高低结内建电场较弱,难以收集电子是FF较低的主要原因.因此,我们用氢化纳晶硅(nc-Si:H)薄膜来代替氢化非晶硅(a-Si:H)薄膜,并且在nc-Si:H薄膜表面覆盖一层超薄高掺杂层进一步提高了载流子传输效率,获得了高达85.3%的FF.此外,三层nc-Si:H薄膜还提高了工艺生产中对掺杂层厚度的容错性,这大大扩展了IBCSHJ太阳电池的工艺窗口.这项工作为解决IBC-SHJ太阳电池的电学问题提供了一条有效的途径,对工艺生产中IBC-SHJ太阳电池的设计具有指导意义.

摘要：The permafrost region is one of the most sensitive areas to climate *** global warming,the Mongolian Plateau permafrost is rapidly degrading,and its vegetation ecosystem is seriously *** address this challenge,it is essential to understand the impact of climate change on vegetation at different permafrost degradation stages on the Mongolian *** on the general permafrost distribution,in this study,we divided different permafrost regions and explored the response of vegetation to climate change at different stages of permafrost degradation by the idea of“space instead of time”from 2014 to *** results of the study showed that:(1)Normalized difference vegetation index(NDVI)values showed a decreasing trend,and the proportion of the decreasing region was in the order of sporadic permafrost region>isolated and sparse permafrost region>continuous and discontinuous permafrost regions.(2)The main controlling factors of vegetation growth in permafrost regions are different,air temperature is the main controlling factor of vegetation growth in isolated and sparse permafrost region(r=-0.736)and sporadic permafrost regions(r=-0.522),and precipitation is the main controlling factor of vegetation growth in continuous and discontinuous permafrost region(r=-0.498).(3)The response of NDVI to climate change varies at different stages of permafrost *** the early stages of permafrost degradation,increased land surface temperature(LST)and air temperature favored vegetation growth and increased vegetation cover,whereas increased precipitation impeded vegetation growth;as the permafrost degraded,increased LST and air temperature impeded vegetation growth,whereas increased precipitation promoted vegetation growth.

摘要：The Mongolian Plateau,a vital ecological barrier in northern China,is of great importance for studying vegetation dynamics in Mongolia against the background of climate *** studies can enhance our understanding of regional vegetation responses to global warming and contribute to the establishment of a stronger ecological barrier in northern ***,we analyzed the spatial and temporal characteristics of the NDVI(normalized difference vegetation index)in Mongolia using 8 km resolution GIMMS NDVI3g data from 1990 to 2022,along with temperature,precipitation,and elevation *** analysis and correlation methods were used to examine the relationships between the NDVI and temperature,as well as *** results showed four important aspects of these relationships.(1)The NDVI in Mongolia increased significantly from 1990 to 2022 at a rate of 0.0015 yr^(-1)(P<0.05).(2)Mongolia’s NDVI increased from 1990 to 2022 in 60.73%of the *** this total,the area with a significant increase accounted for 31.67%and was concentrated on the eastern and western *** area experiencing a significant decrease accounted for 15.67%and was mainly located on the southwestern edges.(3)The NDVI analysis revealed significant increasing trends in all regions except for those at elevations of 1500-2000 *** greatest rate of increase was observed between 500 and 1000 m,and the increasing trend weakened as elevation continued to increase before gradually becoming significant ***,the NDVI increased significantly across different slopes,and the rate of increase decreased as the slope increased.(4)From 1990 to 2022,Mongolia’s NDVI was mostly negatively correlated with *** occurred over 66.75%of the total land area,with 17.21%of the region exhibiting a significant negative correlation,mainly in the ***,the NDVI demonstrated a positive correlation with precipitation,encompassing 86.71%of the total land *** 4

摘要：With the expansion of a city,the urban green space is occupied and the urban heat island effect is *** the roof surfaces of urban buildings is an effective way to increase the area of urban green space and improve the urban ecological *** provide effective data support for urban green space planning,this paper used high-resolution images to(1)obtain accurate building spots on the map of the study area through deep learning assisted manual correction;and(2)establish an evaluation index system of roof greening including the characteristics of the roof itself,the natural environment and the human society *** weight values of attributes not related to the roof itself were calculated by Analytic Hierarchy Process(AHP).The suitable green roof locations were evaluated by spatial join,weighted superposition and other spatial analysis *** the areas within the Chengdu city’s third ring road as the study area,the results show that an accurate building pattern obtained by deep learning greatly improves the efficiency of the *** roof surfaces unsuitable for greening can be effectively classified by the method of feature extraction,with an accuracy of 86.58%.The roofs suitable for greening account for 48.08%,among which,the high-suitability roofs,medium-suitability roofs and low-suitability roofs represent 45.32%,38.95%and 15.73%.The high-suitability green buildings are mainly distributed in the first ring district and the western area outside the first ring district in *** paper is useful for solving the current problem of the more saturated high-density urban area and allowing the expansion of the urban ecological environment.