Multi-subpulse process of large time-bandwidth product chirp signal

To prevent the long-time coherent integration and limited range window stumbling blocks of stretch processing and reduce computational complexity,a novel method called multi-subpulse process of large time-bandwidth product linear frequency modulating(LFM)signal(i.e.chirp)is proposed in this paper.The wideband chirp signal is split up into several compressed subpulses.Then the fast Fourier transform(FFT)is used to reconstruct the high resolution range profile(HRRP)in a relative short computation time.For multi-frame,pulse Doppler(PD)process is performed to obtain the two-dimension range-Doppler(R-D)high resolution profile.Simulations and field experimental results show that the proposed method can provide high-quality target profile over a large range window in a short computation time and has the promising potential for long-time coherent integration.

Strong electronic coupling of CoNi and N-doped-carbon for efficient urea-assisted H2 production at a large current density

Exploiting efficient urea oxidation reaction(UOR)and hydrogen evolution reaction(HER)catalysts are significant for energy-saving H2 production through urea-assisted water electrolysis,but it is still challenging.Herein,carbon-encapsulated CoNi coupled with CoNiMoO(CoNi@CN-CoNiMoO)is prepared by solvothermal method and calcination to enhance the activity/stability of urea-assisted water electrolysis at large current density.It exhibits good activity for UOR(E10/1,000=1.29/1.40 V)and HER(E-10/-1000=-45/-245 mV)in 1.0 M KOH+0.5 M urea solution.For the UOR||HER system,CoNi@CN-CoNiMoO only needs 1.58 V at 500 mA cm-2 and shows good stability.Density functional theory calculation suggests that the strong electronic interaction at the interface between NiCo alloy and N-doping-carbon layers can optimize the adsorption/desorption energy of UOR/HER intermediates and accelerate the water dissociation,which can expedite urea decomposition and Volmer step,thus increasing the UOR and HER activity,respectively.This work provides a new solution to design UOR/HER catalysts for H2 production through urea-assisted water electrolysis.

Dendritic cells derived from pluripotent stem cells:Potential of large scale production

Human pluripotent stem cells(hPSCs), including human embryonic stem cells and human induced pluripotent stem cells, are promising sources for hematopoietic cells due to their unlimited growth capacity and the pluripotency. Dendritic cells(DCs), the unique immune cells in the hematopoietic system, can be loaded with tumor specific antigen and used as vaccine for cancer immunotherapy. While autologous DCs from peripheral blood are limited in cell number, hPSC-derived DCs provide a novel alternative cell source which has the potential for large scale production. This review summarizes recent advances in differentiating hPSCs to DCs through the intermediate stage of hematopoietic stem cells. Step-wise growth factor induction has been used to derive DCs from hPSCs either in suspension cultureof embryoid bodies(EBs) or in co-culture with stromal cells. To fulfill the clinical potential of the DCs derived from hPSCs, the bioprocess needs to be scaled up to produce a large number of cells economically under tight quality control. This requires the development of novel bioreactor systems combining guided EB-based differentiation with engineered culture environment. Hence, recent progress in using bioreactors for hPSC lineage-specific differentiation is reviewed. In particular, the potential scale up strategies for the multistage DC differentiation and the effect of shear stress on hPSC differentiation in bioreactors are discussed in detail.

Association of polymorphisms of Nramp1 gene with immune function and production performance of large white pig

The present research was designed to study the association of polymorphism of natural resistance-associated macrophage protein1 (Nramp1) with some immune function and the production performance in Large White pig. The PCR-RFLP technique was applied to analyze the correlation between the polymorphisms of Nramp1 gene and immune function [value of Polymorphonuclear Leukocytes (PMN) obtained by Nitroblue Tetrazolium (NBT) Reduction and effect of Cytotoxin in Monocyte] and production performance in 165 Large White pigs. The results showed that there was one Nde I restriction locus in Large White pig, and both values of PMN by NBT Reduction and effect of Cytotoxin in Monocyte in genotype BB were higher than those in genotype AB (P<0.05). Simultaneously, the weight of 180-day-old pigs with genotype BB was higher than that with genotype AB (P<0.05). The results indicated that there was a significant correlation between different genotypes of Nramp1 gene and Immune function and production performance, and it can be regarded as a candidate gene of disease resistance. All these results provide valuable reference to further studies of pig disease resistance.

Small Optical Product Breeds Large Industry

China is the world’s largest consumer market for eyeglasses,with the total market volume reaching 80billion yuan.Accordingly,the market has a group of 800 million consumers demanding eyeglasses.The consumers are from different ages。

A LARGE EXQUISITE PRODUCT——OF SUZHOU EMBROIDERY "RETURN JOURNEY"

Alarge exquisite product of Suzhou embroidery—"Return Journey" is a precious gift to the Government of the Hongkong Special Administrative Region from the Jiangsu Provincial People’s Government marking Hongkong’s return.

A method of manufacturing process modeling based on activity network for large-sized and complex products

Simulation technique is an efficient approach to realize the planning and scheduling of manufacturing process of products. An appropriate and efficient manufacturing process model is the basis and key of manufacturing process simulation. By analyzing the features of large-sized and complex products, a method of manufacturing process modeling based on activity network is presented and a mapping algorithm of translating BOM/BOP into the manufacturing process model is designed in detail.

Study on the Production Benefit of Large-scale Tobacco Growers

The tobacco growers with the growing area of greater than or equal to 100 mu,have become an important subject of tobacco production in Weng'an County of Guizhou Province. Regulating and developing the production and business activities of large-scale tobacco growers, plays an important role in stabilizing tobacco production,reducing costs and increasing efficiency in Weng'an County. Through the field survey of large-scale growers' production activities,this article analyzes the input and output levels,and explores the key factors influencing benefit, in order to provide a basis for further regulating the tobacco growing practices and improving the flue-cured tobacco production benefit.

Minimal Generalized Time-Bandwidth Product Method for Estimating the Optimum Fractional Fourier Order

A minimal generalized time-bandwidth product-based coarse-to-fine strategy is proposed with one novel ideas highlighted: adopting a coarse-to-fine strategy to speed up the searching process. The simulation results on synthetic and real signals show the validity of the proposed method.

Photonics Improvement of the Time-Bandwidth Product for a Linearly Chirped Waveform

A photonics approach to generate a linearly chirped waveform with increased TBWP is proposed and investigated. The time bandwidth product (TBWP) of the linearly chirped waveform is improved based on optical microwave frequency multiplying combined with temporal synthesis. An integrated dual-polarization modulator and an optical filter are utilized to perform frequency doubling operation by generating an orthogonally polarized optical signal, which consists of an optical carrier in one polarization direction and a second-order chirped optical sideband in another. Then the orthogonally polarized optical signal puts into a polarization modulator (PolM) to perform phase coding process. By driving a Pseudorandom (PN) sequence to the PolM, the time duration of the generated bandwidth doubled linearly chirped waveform can be synthesized to arbitrary length. The approach is verified by simulation. A linearly chirped waveform with central frequency of 8.25 GHz, bandwidth of 500 MHz, time duration of 6.4 ns is used to generate a synthesized waveform with central frequency of 16.5 GHz, bandwidth of 1 GHz, time duration of 819.2 ns. The TBWP of the linearly chirped signal is improved from 3.2 to 819.2. The proposed method features arbitrary large TBWP, and it can be used in a radar system to improve its resolution.

Series Design of Large-Scale NC Machine Tool

Product system design is a mature concept in western developed countries. It has been applied in war industry during the last century. However,up until now,functional combination is still the main method for product system de-sign in China. Therefore,in terms of a concept of product generation and product interaction we are in a weak position compared with the requirements of global markets. Today,the idea of serial product design has attracted much attention in the design field and the definition of product generation as well as its parameters has already become the standard in serial product designs. Although the design of a large-scale NC machine tool is complicated,it can be further optimized by the precise exercise of object design by placing the concept of platform establishment firmly into serial product de-sign. The essence of a serial product design has been demonstrated by the design process of a large-scale NC machine tool.

As Could We Assure Safety in Large-Scale Manufacturing of Nanoparticles for the Biomedical Use

Nanoparticles provide great advantages but also great risks. Risks associating with nanoparticles are the problem of all technologies, but they increase in many times in nanotechnologies. Adequate methods of outgoing production inspection are necessary to solve the problem of risks, and the inspection must be based on the safety standard. Existing safety standard results from a principle of “maximum permissible concentrations or MPC”. This principle is not applicable to nanoparticles, but a safety standard reflecting risks inherent in nanoparticles doesn’t exist. Essence of the risks is illustrated by the example from pharmacology, since its safety assurance is conceptually based on MPC and it has already come against this problem. Possible formula of safety standard for nanoparticles is reflected in many publications, but conventional inspection methods cannot provide its realization, and this gap is an obstacle to assumption of similar formulas. Therefore the development of nanoparticle industry as a whole (also development of the pharmacology in particular) is impossible without the creation of an adequate inspection method. There are suggested new inspection methods founded on the new physical principle and satisfying to the adequate safety standard for nanoparticles. These methods demonstrate that creation of the adequate safety standard and the outgoing production inspection in a large-scale manufacturing of nanoparticles are the solvable problems. However there is a great distance between the physical principle and its hardware realization, and a transition from the principle to the hardware demands great intellectual and material costs. Therefore it is desirable to call attention of the public at large to the necessity of urgent expansions of investigations associated with outgoing inspections in nanoparticles technologies. It is necessary also to attract attention, first, of representatives of state structures controlling approvals of the adequate safety standard to this problem, since it is impossible to compel producers providing the safety without the similar standard, and, second, of leaders of pharmacological industry, since their industry already entered into the nanotechnology era, and they have taken an interest in a forthcoming development of inspection methods.

发展新质生产力 推动我国经济高质量发展

中华人民共和国(新中国)成立以来,从毛泽东的《论十大关系》,到邓小平的“科学技术是第一生产力”,再到习近平的“整合科技创新资源,引领发展战略性新兴产业和未来产业,加快形成新质生产力”,我党对经济工作规律性的认识,随着时代的发展而不断深化。习近平总书记在2024年1月31日召开的中央政治局第十一次集体学习会议上的重要讲话,更是把这种认识推向了全新的高度。总书记在主持学习时明确指出“必须牢记高质量发展是新时代的硬道理”,“高质量发展需要新的生产力理论来指导,而新质生产力已经在实践中形成并展示出对高质量发展的强劲推动力、支撑力,需要我们从理论上进行总结、概括,用以指导新的发展实践”,并强调“科技创新能够催生新产业、新模式、新动能,是发展新质生产力的核心要素”。为了深入学习贯彻总书记讲话精神,围绕“发展新质生产力推动我国经济高质量发展”这个新时代经济发展的核心课题,本刊邀请国内著名专家、学者,撰写一组笔谈文章,以飨读者。

大语言模型时代的开源知识生产:机遇、挑战与未来

随着大语言模型的崛起,开源知识生产领域迎来了新的变革。大语言模型对开源知识生产的积极影响及其潜在挑战并存。一方面,大语言模型通过适应开源社区的坎宁安定律、提供全天候的新人知识培训支持,以及通过领域化构建策略来修正知识生产的系统性偏差,显著提升了开源知识的生成与传播效率;另一方面,大语言模型带来的幻觉现象、版权风险、数字剥削问题以及“死亡互联网”趋势的加剧,对开源知识的核查、合法性、价值观以及生态环境构成了严重威胁。基于此,未来应强化人类认知体验在引导大语言模型技术发展中的核心作用,并通过实践不断探索解决方案,以期实现大语言模型知识生产与开源知识生产的和谐共生及共同进步。

超大规模市场优势、复杂创新能力与培育新质生产力的内在逻辑

新质生产力区别于传统生产力,是科技创新密集型生产力。随着新一轮科技革命和产业变革深入发展、国际力量对比的深刻调整,全球在产业、关键核心技术上的竞争日益加剧,新质生产力将成为大国博弈的重要阵地。面对西方国家的技术封锁和打压,我国唯有充分发挥国内“超大规模市场”的系统性优势和适宜型创新优势,提升企业复杂创新能力和产业组织生态力,从而培育新质生产力:一是深化体制机制改革,推动超大规模市场“潜在优势”转变为“现实优势”;二是发挥超大规模市场优势,强化国家战略科技力量,提升我国关键核心技术攻关能力;三是要整合大国创新资源,夯实基础研究,提升原始创新能力;四是发挥大国超大规模市场创新人才优势,建设全球人才高地。

葡萄糖酸钠对大掺量石灰石粉水泥浆体水化行为的影响

为了研究葡萄糖酸钠对大掺量石灰石粉水泥浆体水化行为的影响,采用等温量热测试、X射线衍射测试、热重测试研究了胶凝材料体系的水化进程、水化产物种类与含量的变化;并采用相边界成核与生长模型探究了葡萄糖酸钠作用下大掺量石灰石粉水泥水化产物成核与生长机制。结果表明:葡萄糖酸钠能够延缓大掺量石灰石粉水泥的水化,减少水化产物的生成,从而降低其水化程度;另外,葡萄糖酸钠能够降低水化产物早期成核与生长的速率,减小水化产物早期在相边界成核与生长的面积。

面向新质生产力发展的科技人才数据底座建设

[目的/意义]通过科技人才数据底座建设,助力人才发展决策科学化,促进新质科技人才引育精准化,推动科技人才评价改革落地,推进新质生产力人才体系建设。[方法/过程]通过剖析科技人才数据底座建设的现实要求和意义,研究和分析科技人才数据底座助力新质生产力发展的内在逻辑,针对当前科技人才数据底座建设面临的挑战,提出科技人才数据底座的建设思路,开展研究探索与应用实践。[结果/结论]科技人才数据底座建设是数智时代发展的客观要求,也是新质生产力形成的必然要求。构建科技人才大数据,数智赋能人才工作流程,构筑科技人才数据底座,有助于激活数据在人才资源配置中的作用,加速科技创新,推动新质生产力发展。

岩藻黄素产业化技术研究进展

岩藻黄素(Fucoxanthin),又称岩藻黄质、褐藻黄质、褐藻黄素,是一种具有抗氧化活性的天然类胡萝卜素,主要来源于褐藻、微藻(如微藻、金藻)等海洋藻类。岩藻黄素具有较大的市场开发潜力,但产业化程度较低,针对这一问题,该文首先概述了岩藻黄素物化特性及抗氧化、抗肿瘤、抗肥胖、抗炎等功能特性,并对岩藻黄素生产的上游开发和下游加工技术研究现状进行综述性介绍,详细介绍了岩藻黄素的上游开发(生物合成途径、生产藻类筛选、培养方法及条件)和下游加工技术(提取纯化方法、稳态化制剂、产品生产技术),指出目前存在的技术瓶颈并提出可能的解决方案,最后分别介绍了岩藻黄素在食品、化妆品和医药等领域的应用现状。该文将为未来岩藻黄素产业化技术研究提供借鉴价值。

大段多簇压裂改造技术优化与页岩气储层分析应用

YA45G5平台下志留统龙马溪组页岩气储层物性差,非均质性强,水平井精准改造优势储层的难度大,分段压裂方式增产效果有限,压裂投入高、产出低的矛盾突出。针对这些问题,采用连续油管和电缆传输分簇射孔技术可以改善压裂液在段内各簇中的分布,优化压裂施工参数,促进裂缝均匀起裂,形成了适用于太阳-大寨区块油藏的水平井大排量、大段多簇、高强度加砂压裂技术,取得了显著的降本增产效果,为国内页岩气储层的开发提供有益经验。