The essential factor in laser frequency conversion involves phase matching within nonlinear optical crystals. To our knowledge, few studies have investigated the noncollinear phase matching calculation for biaxial crystal out of the principal plane. In this paper, we propose an arbitrary direction phase matching model and a computational method based on gradient descent (GD) algorithm, which can be applied to noncollinear in the principal plane, collinear and noncollinear out of the principal plane. In the case of 1053 nm third harmonic generation (THG) in LiB3O5 (LBO) crystal, the phase matching conditions are converted into a system of nonlinear equations with six variables and six equations, which can be solved by iterative optimization search with the GD algorithm and includes type-I (ss-f) and type-II (fs-f). We reveal the relationship of phase matching angles and effective nonlinear coefficients ( d_eff ) for various structures. Our method uncovers the existence of many solutions in the non-principal plane with γ > 8° and the d_eff close to the maximum value 0.66834 pm/V at θ = 90°, φ = 141.84° and γ = 0. The resolution of the arbitrary direction phase matching problem holds significant importance, as it expands the possibilities for laser frequency conversion, especially for noncollinear structures.

Nanoscale science and technology(nano S&T)are at the frontier of global strategic high-tech competition.After examining nearly 160 strategy and planning documents released by scientific and technological powerhouses from 2000 to 2023,the study finds ten common approaches adopted by the powerhouses to advance nano S&T as follows.(1)Recognizing nano S&T as a key area for the economy and global competition.(2)Establishing cross-department organizations to meet the cross-disciplinary nature of nano S&T.(3)Developing strategic plans to guide the development of nano S&T and implementing major programs with significant investment.(4)Establishing multidisciplinary nano S&T research centers based upon institutions with strength.(5)Building and maintaining physical and cyber R&D infrastructures for nano S&T.(6)Promoting convergence of nanotechnology,information technology,biotechnology,and cognition science.(7)Establishing facilities to accelerate the commercialization of promising discoveries.(8)Paying close attention to the possible effects of nano S&T on the environment and human health.(9)Developing a skilled workforce and recruiting overseas talents.(10)Engaging in international collaborations.The study also finds that the powerhouses have continued to pay close attention to nano S&T during the past three years,focusing on issues such as leveraging nano S&T to help address significant societal challenges and preparing for the oncoming data-intensive R&D paradigm.Moreover,the study discusses the progress and shortcomings of nano S&T in China and proposes suggestions for R&D in the future after taking account of the findings presented above.The suggestions include promoting the commercialization of promising R&D,building and maintaining nanomaterial databases,establishing nano S&T think tanks,and putting in place a system of developing talent who can adapt to scientific and technological trends and meet the demands of the development of nano S&T.

未来10—15年,科技进步在改变产业结构和全球经济增长方向的同时,将深刻改变人自身对衣食住行等诸多方面的需求及其满足形式。借鉴世界主要国家、国际组织或企业面向未来在经济社会与科技创新发展领域进行的前瞻与预见工作,通过深入系统的信息和知识元分析,从社会发展趋势、未来发展愿景、具体场景、未来关键技术群4个方面,文章重点阐述了生活、工作、健康、信息、安全5个领域的全景图,为擘画中国未来一段时期发展愿景和科技创新需求场景提供参考。

Objective The accuracy of a quadri -wave lateral shearing interferometer is directly affected by the accuracy of the wavefront reconstruction. Traditional wavefront-reconstruction methods include modal and zonal methods. The modal method expands the wavefront into a set of primary functions to be measured, then fits the coefficients corresponding to the primary functions to reconstruct the measured wavefront. The zonal method discretizes the measured wavefront to establish a mapping relationship between the measured and differential wavefronts for reconstruction. Alternatively, the wavefront can be reconstructed by direct integration in the shearing direction. However, the modal method always uses finite terms to fit the measured wavefront, which directly ignores high -frequency information, reducing the estimated accuracy of the quadri -wave lateral shearing interferometer. The zonal method has a high spatial resolution, but the noise error accumulates along the integrated path during the reconstruction process, forming noise lines, thus, affecting the accuracy of the reconstructed wavefront. To solve this problem, a quadri -wave lateral shearing interferometric wavefront reconstruction method is proposed based on path guidance, which has both high accuracy and spatial resolution. Methods In this study, a theoretical analysis of the drawbacks of noise error accumulation in wavefront reconstruction using the zonal method without integral -path guidance under noisy environments is carried out. An integral -path evaluation -map model is established based on the deviation of differential phase derivatives, and a flowchart of the wavefront reconstruction algorithm is provided based on integral -path guidance. The proposed method consists of two steps. First, the evaluation model of the differential -phase -derivative deviation is used to count the variational characteristics of the differential phase, identify the noise error, and generate an integral path to avoid noise error. Second, the generated path is used to guide the wavefront reconstruction integral of the Southwell model. Using theoretical simulations, the proposed method could effectively prevent the propagation and accumulation of noise errors compared to the zonal method without integral -path guidance under noisy environments for different signal-to-noise ratios (SNRs). In addition, a verification device having a pure -phase liquid -crystal spatial light modulator (SLM) was set up to experimentally verify the effectiveness of the proposed method. The experimental results of the proposed method were also compared with those of the zonal method without integral -path guidance. Results and Discussions In the simulation, interferograms with a sinusoidal phase distribution are generated (Fig. 4). When the SNR increases from 10 dB to 50 dB, the root -mean -square (RMS) between the wavefront reconstructed by the zonal method without integral -path guidance and the theoretical wavefront decreases from 0.0152A to 0.0094A. However, the RMS between the wavefront reconstructed by the proposed method and the theoretical wavefront decreases from 0.0139A to 0.0041A. Moreover, the proposed method reduces the RMS of the reconstructed and theoretical wavefronts by a maximum of 55.6% compared to the zonal method without integral -path guidance (Fig. 7). Thus, the proposed method is more robust than the zonal method without integral -path guidance under the Gaussian noise environment with different SNRs (Fig. 6). In the experiment, we measure the random phase generated by the spatial light modulator using the proposed method and zonal method without integral -path guidance (Fig. 10). The results show that the PV value (peak -valley value) of the wavefront reconstructed by the proposed method is 0.7283A, whereas that of the wavefront reconstructed by the zonal method without integral -path guidance is 2.966A. The deviation between the PV value of the wavefront reconstructed by the proposed method and that of the theoretical wavefront is 1.6943A, which is less than the deviation between the wavefront PV value reconstructed by the zonal method without integral -path guidance and the theoretical wavefront PV value (Fig. 13). In addition, the RMS between the wavefront reconstructed by the proposed method and the theoretical wavefront is reduced by 39.7% compared with the RMS between the wavefront reconstructed by the zonal method without integral -path guidance and the theoretical wavefront. In addition, the zonal method without integral -path guidance is used to reconstruct the wavefront, which propagates and accumulates noise points along the shearing direction by forming noise lines. However, the proposed method prevents the propagation of noise points and improves wavefront reconstruction accuracy. Conclusions This paper proposes a quadri -wave lateral shearing interference wavefront reconstruction method based on integral -path guidance. The effectiveness of the proposed method is verified through theoretical simulations and experiments. The theoretical simulation results show that the proposed method prevents the propagation of noise errors and improves the wavefront reconstruction accuracy compared to the zonal method without integral -path guidance under noisy environments with different SNRs. The RMS between the reconstructed wavefronts of the proposed method and the theoretical wavefront is smaller than that between the zonal method without integral -path guidance and the theoretical wavefront under the same conditions. Moreover, the experimental results show that the proposed method can effectively prevent the propagation and accumulation of differential phase noise points when measuring the random phase generated by the pure -phase liquid crystal spatial light modulator and reconstructing the wavefront of the random phase. However, the wavefront of the random phase reconstructed using the zonal method without integral -path guidance cannot be accurately reconstructed because of the noise line generated by the accumulation of noise. Therefore, the proposed method has higher accuracy and robustness than the zonal method without integral -path guidance in reconstructing the wavefront in a noisy environment.

未来产业是由颠覆性技术突破牵引、满足未来社会发展需求的新兴产业,将为经济社会发展创造全新动力,推动人类生产生活方式深刻变革,也是世界主要国家把握未来发展主动权、占据竞争制高点的关键.新冠肺炎疫情暴发以来,公共卫生与人口健康、产业链与供应链安全、数字经济与数字主权等问题凸显,全球发展都受到了极大的冲击,通过技术和产业变革引领经济社会转型发展成为各国共识,我国"十四五"规划明确提出要"前瞻谋划未来产业",世界主要国家进一步加速未来产业布局,呈现出若干特点与趋势.为在全球竞争中把握发展主动权,我国应高度关注世界各国对未来产业的最新部署重点与发展路径.

从整体布局、管理机制、建设模式等角度,基于法国官方披露路线图、审计报告等,分析法国重大科技基础设施建设布局特点与近20年发展趋势.研究得出:(1)法国设施学科范围持续扩大、跨领域特征明显,能源转型、数据管理和生物健康逐渐成为关注焦点;(2)大型设施数量保持稳定,以材料、核物理和天体物理为主,设施类型从单体式向分布式、虚拟式转变;(3)以核心国立科研机构为管理机构、根据设施性质采取多元管理的模式行之有效;(4)重大科技基础设施的集群化建设符合国家科技创新与产业发展的规律,集群效应在长时间周期不断凸显.基于此,提出建设和管理我国重大科技基础设施的建议,如国家统筹布局、总体规划,提高设施使用效能,拓展管理模式,提高管理灵活性等.

文章对全球主要经济体的碳中和战略取向、目标设定、政策措施等进行系统梳理。研究显示，由于社会基础、经济基础和政治基础各不相同，主要经济体的碳中和战略取向也不同，可分为引领型、增长型、跟随型、摇摆型 4 类。这些经济体基本按照“目标路线图+关键领域目标”的框架构建碳中和目标体系，但引领型通常完成立法并制定严格的减排目标，其他类型往往弱化减排目标约束而关注新兴行业增长目标等。其主要根源在于，现有技术不足以支撑实现碳中和。因此，碳中和科技创新得到各国普遍重视，力求占据产业竞争制高点，但欧美追求“本土制造”的做法可能不利于降低新技术成本；在市场激励上，碳排放权交易市场被普遍采用，但碳定价机制仍有待进一步优化。全球主要经济体碳中和相关措施对我国制定完善碳中和政策有重要的启示意义。

中国中央和地方的"十四五"规划中,明确提出发展未来产业.文章通过世界主要国家未来产业发展部署展开分析,以期为中国未来产业的发展提供决策参考.通过收集美国、日本、英国、法国、德国、韩国、俄罗斯共7个国家22个未来产业发展规划,对未来产业的概念、特征、战略意义和趋势进行分析,详细研究了这7个国家未来产业的部署,总结了各国发展未来产业的经验,并对我国发展未来产业提出3点启示:未来产业发展应上升为国家战略并统筹编制我国未来产业发展规划与路线图,中国科学院等智库应针对未来产业系统开展研究,以及加大对未来产业关键技术研发布局力度.

院士制度作为一个国家科学体制化的标志性产物,从一定程度上影响着一个国家科学的发展和学科的演进.在比较视野下,本研究梳理了欧美主要国家院士群体学科发展的历程,对美英德法四国的院士增选制度、学部及学科布局、学部在增选中发挥的影响,以及过去20年院士群体学科发展态势进行了分析和比较.在此基础上,总结了欧美主要国家院士群体学科布局演进特点,旨在为我国院士群体学科布局及建设提供借鉴.

水下自航靶是目前使用最为广泛地用于模拟潜艇的水下靶标,作为海军反潜装备训练、试验及鉴定的重要资源,对海军反潜装备技术发展、反潜武器装备质量和可靠性检验、反潜战略战术训练有着十分重要的作用.目前,世界主要国家均根据各自海军建设需求,研制了多种型号的水下自航靶,构建起相对完整的发展体系.通过概述水下自航靶的发展历程,并以各国目前性能先进的水下自航靶为研究对象,详细梳理每种型号的基本情况、研制机构和性能参数,从结构、功能、使用等方面分析其特点,总结世界主要国家水下自航靶装备的发展特点,为我国水下自航靶体系发展提供借鉴和参考.

The iterative phase retrieval based on phase diversity technologies can solve the stagnation problem of Gerchberg–Saxton algorithm which performs Fourier transform to iterate back and forth between the object and spectral planes with known constraints. However, the application of phase diversity technologies in iterative phase retrieval methods will bring in multiple physical parameters such as distances or wavelengths. The measured accuracy of these physical parameters will ultimately affect the accuracy of the iterative phase retrieval methods. In this paper, a physical parameters estimation method which has the advantages of high global convergence and local convergence is proposed to improve the accuracy of iterative phase retrieval methods. Meanwhile, this method is introduced in the single-beam multiple-intensity reconstruction (SBMIR), termed PE-SBMIR, and its performance is verified by simulations and experiments. By simulating multiple sets of distance parameters with errors, the retrieved accuracy using PE-SBMIR can be improved by 2–4 orders of magnitude compared with SBMIR. Experimental results show that whether it is an amplitude-type object or phase-type object, the accuracy using PE-SBMIR is significantly higher than using SBMIR. The physical parameters estimation method proposed in this paper may be adopted in other iterative phase retrieval methods using phase diversity technologies.

法国医学健康科技创新体系具有鲜明的特点,在主管科技和主管卫生的政府部门指导下,由权威的国立科研机构引领整个领域的研究发展,由多个资助机构针对不同研究方向资助项目,由主要科技创新主体组成科学联盟起总体规划与协调作用,由医学科学院提供咨询建议,各部分各司其职又充分合作,是集中与分散并存的组织机制.本文通过全面梳理法国医学健康科技创新体系,逐一介绍医学健康研究的主管部门、资助机构、研发机构、规划与协调机构、咨询机构等,分析其组织机制与特点,以期为我国完善医学健康科技创新体系、推动医学健康研究发展提供一些参考.

由于国家在一个时期内的科技投入的方向和强度最能反映出国家未来科技发展趋势,本研究提出构建基于科技投入和核心技术的政策要素知识图谱,意欲分析得出各国科技发展方向及趋势的情报,从而支撑科技发展布局与趋势研判.本研究总结了情报监测的科技政策文本中支撑情报分析的关键要素,提出了基于政策要素的知识图谱模型,探索了智能计算的政策分析方法.通过对美国、英国、法国、德国、日本和韩国近年科技投入的优先领域、技术、资助项目、资助强度等相关知识的信息抽取和内容分析,形成了基于领域的政策知识图谱,并利用两个实例演示了基于知识图谱的情报检索与分析效果.本技术对情报分析人员、决策人员审视宏观科技布局和前瞻科技发展方向有所帮助.

The transient radial shearing interferometry technique based on fast Fourier transform (FFT) provides a means for the measurement of the wavefront phase of transient light field. However, which factors affect the spatial bandwidth of the wavefront phase measurement of this technology and how to achieve high-precision measurement of the broad-band transient wavefront phase are problems that need to be studied further. To this end, a theoretical model of phase-retrieved bandwidth of radial shearing interferometry is established in this paper. The influence of the spatial carrier frequency and the calculation window on phase-retrieved bandwidth is analyzed, and the optimal carrier frequency and calculation window are obtained. On this basis, a broad-band transient radial shearing interference phase-retrieval method based on chirp Z transform (CZT) is proposed, and the corresponding algorithm is given. Through theoretical simulation, a known phase is used to generate the interferogram and it is retrieved by the traditional method and the proposed method respectively. The residual wavefront RMS of the traditional method is 0.146 λ , and it is 0.037 λ for the proposed method, which manifests an improvement of accuracy by an order of magnitude. At the same time, different levels of signal-to-noise ratios (SNRs) from 50 dB to 10 dB of the interferogram are simulated, and the RMS of the residual wavefront is from 0.040 λ to 0.066 λ . In terms of experiments, an experimental verification device based on a phase-only spatial light modulator is built, and the known phase on the modulator is retrieved from the actual interferogram. The RMS of the residual wavefront retrieved through FFT is 0.112 λ , and it decreases to 0.035 λ through CZT. The experimental results verify the effectiveness of the method proposed in this paper. Furthermore, the method can be used in other types of spatial carrier frequency interference, such as lateral shearing interference, rotational shearing interference, flipping shearing interference, and four-wave shearing interference.

In this paper, a new phase retrieval method using sequential phase modulations is proposed. Behind the unknown object, adding sequential phase modulations will change the diffraction intensities received by sensor. Through increasing the number of diffraction intensities patterns, the difficulty of retrieving the unknown object is decreased. To better select these modulation phases, the complexity parameter is defined to evaluate the complexity of unknown object. When the complexity parameter of unknown object is larger, it contains more spectrum information on different frequency bands and will be harder to retrieve. The complexity of unknown object should be contained between the maximum and minimum complexities of modulation phases. In this way, the information of each frequency band on the unknown object can be effectively retrieved. Meanwhile, the distribution of modulation phases should be continuous to avoid introducing high frequency noise. In addition, there is no limit on what kind of modulation phase distribution to choose. The effectiveness and fast convergence of this new method has been proved.

分析了Yet2、欧洲企业服务网络(EEN)、法国加速技术转移公司网络(SATT)、韩国国家技术银行(NTB)、芬兰FinNode网络等技术交易平台的运行机制及管理制度,结合当代技术交易活动以及相关创新创业辅助工作情况,总结了主要发达国家技术交易平台建设发展工作的特点,进而提出了对中国新一代技术交易平台建设工作的建议,明确将企业作为技术交易的关键主体、呈现国际化和规模化趋势、面向产业创新创业全过程服务.

对美国、英国、德国、法国、日本、加拿大、澳大利亚等国家开展深入系统的情报资料文献调研,利用信息分析工具对这些政策文本进行了文本数据挖掘与分析,对分析得到的政策影响要素进行了分析整理和系统构建,初步建立了新一轮科技革命的"政策要素框架".结合系统分析方法对主要国家2013年以来应对科技革命的战略与政策进行了梳理与分析,初步总结了这些国家的政策概况、重点及发展趋势.

文章广泛调研了近10年美国、欧盟、英国、法国、德国、日本等国家和地区在能源领域出台的各种官方文件,通过内容分析等研究方法,从战略规划、经费投入、科研布局、组织机制等角度对上述国家和地区的能源政策进行分析.发现各个国家和地区能源政策呈现出一些共同特征,包括:自身资源禀赋是制定能源政策的基础,能源多元化和清洁高效利用是各国能源政策共同目标,科技创新是实现目标的重要抓手.最后,就我国抓住能源变革机遇、打造能源新体系,提出了一些建议.

随着历史的发展和社会的进步,人们为自然节气和特殊事件发生的时间点赋以特殊的纪念意义和相关仪式,这样就有了节日.这些节日表面上是时间点,但蕴含了深刻的意义,既是进行时间分段的节点,又是对前人功绩的纪念和提醒.人们或者庆祝丰收与工作顺利,休息身心蓄积力量;或者总结经验,继往开来.

To ensure the status of world-class scientific research power, and respond to scientific, technological and societal challenges, the French Ministry of Research released a new national strategy "France-Europe 2020" on March 5, 2015. The strategy is the second French national research strategy after "National Research and Innovation Strategy 2009". It has set 10 research priorities focusing on the major societal challenges, proposes 5 action plans and emphasizes application-oriented research to resolve the major societal challenges. This paper analyzes the development process and main contents of "France-Europe 2020", summarizes its typical features, as a reference for making Chinese scientiifc research strategy.