News on China's scientific and technological development.

tokenanalyst

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Putting money on a balance sheet doesn't cause results to happen. Doing the work causes results to happen. Money without work is just inflation.

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DJI dominate the drone world and is not even in the list, so that company of get a lot out of their R&D. Other companies just like to fill patents and tax other companies with their IP, that is the case of modern IBM.

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gadgetcool5

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About a fifth of the talent who contributed to the creation of ChatGPT 4 are ethnic Chinese. I guess the pay is still higher here. O/c these are all nameless and faceless, Sam Altman gets all the credit.

Shame for China that Biden dropped the China Initiative. China needs even more discrimination against ethnic Chinese scientists to smoke all these people back to the "motherland.'
 

tokenanalyst

Brigadier
Registered Member

About a fifth of the talent who contributed to the creation of ChatGPT 4 are ethnic Chinese. I guess the pay is still higher here. O/c these are all nameless and faceless, Sam Altman gets all the credit.

Shame for China that Biden dropped the China Initiative. China needs even more discrimination against ethnic Chinese scientists to smoke all these people back to the "motherland.'
Well the Biden administration has set the bar so low that if Trump or the GOP gets in power it would be recommended to migrate as soon as possible.
 

Eventine

Junior Member
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About a fifth of the talent who contributed to the creation of ChatGPT 4 are ethnic Chinese. I guess the pay is still higher here. O/c these are all nameless and faceless, Sam Altman gets all the credit.

Shame for China that Biden dropped the China Initiative. China needs even more discrimination against ethnic Chinese scientists to smoke all these people back to the "motherland.'
20% is pretty low considering the number of ethnic Chinese researchers in AI.

It's possible Peter Thiel - one of the founders of Open AI - had a hand in that, since his other company Palantir was also caught discriminating against Asian candidates in hiring.
 

siegecrossbow

General
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Award winning manta-ray bot. Coming to a boomer sub near you!

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SanWenYu

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More than 50% of the mobile internet traffic in China are now on IPv6. China has completed the construction of its IPv6 infrastructure.

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数据显示,2023年2月,我国移动网络IPv6占比达到50.08%,首次实现移动网络IPv6流量超过IPv4流量的历史性突破。这意味着我国IPv6网络“高速公路”已全面建成,信息基础设施IPv6服务能力已基本具备。

所谓IPv6就是可以提供比现在更多的网址资源的互联网协议。目前广泛使用的IPv4(互联网协议第四版)能提供40多亿个IP地址,由于互联网的普及,现在这些网址资源已经接近枯竭。

中国信息通信研究院技术与标准研究所副所长 曹蓟光:它(IPv6)把IP的地址空间扩大到128位,足够未来信息社会对地址的空间需求,它是互联网未来的底座。我们国家加快发展以IPv6为基础的互联网,一方面能够跟全球互联互通,另一方面基于新的平台,我们可以做更多自主可控的一些创新。

我国在《数字中国建设整体布局规划》和《国民经济和社会发展第十四个五年规划和2035年远景目标纲要》中都提出要深入推进IPv6规模部署和应用。随着IPv6规模部署不断深化,推动IPv6网络实现从“能用”到“好用”,并向“爱用”的跨越,将成为下一阶段我国IPv6发展的重要目标。
 

SanWenYu

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New piezoelectric ceramics for making better sonars?

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Lead zirconate titanate ceramics with aligned crystallite grains​

A winning template​

Lead zirconate titanate piezoelectrics are important for making transducers, sensors, and other components for electromechanical applications. To expand the usable temperature range and electromechanical coupling factor, Li et al. introduce a texturing process for lead zirconate titanate–based materials. A sacrificial template both changes the composition of the solid solution and orients the crystals to improve the piezoelectric properties. —BG

Abstract​

The piezoelectric properties of lead zirconate titanate [Pb(Zr,Ti)O3 or PZT] ceramics could be enhanced by fabricating textured ceramics that would align the crystal grains along specific orientations. We present a seed-passivated texturing process to fabricate textured PZT ceramics by using newly developed Ba(Zr,Ti)O3 microplatelet templates. This process not only ensures the template-induced grain growth in titanium-rich PZT layers but also facilitates desired composition through interlayer diffusion of zirconium and titanium. We successfully prepared textured PZT ceramics with outstanding properties, including Curie temperatures of 360°C, piezoelectric coefficients d33 of 760 picocoulombs per newton and g33 of 100 millivolt meters per newton, and electromechanical couplings k33 of 0.85. This study addresses the challenge of fabricating textured rhombohedral PZT ceramics by suppressing the otherwise severe chemical reaction between PZT powder and titanate templates.

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西安交大织构压电陶瓷研究成果在《科学》期刊发表​

4月7日,《科学》期刊在线发表了西安交通大学在高性能织构压电陶瓷方面的最新研究成果—《晶粒定向排列的锆钛酸铅陶瓷》(Lead zirconate titanate ceramics with aligned crystallite grains)。

压电材料是一种能够实现机械能与电能相互转换的功能材料,广泛应用于医学超声诊断、精密驱动控制、深海通讯、无损检测等诸多重要领域。作为一类最经典的铁电固溶体,锆钛酸铅[Pb(Zr, Ti)O3,PZT]陶瓷以优异的压电性能和较宽的温度使用范围成为了众多压电器件的核心材料。由于PZT陶瓷的性能直接影响了压电器件的使用效能,因此增强PZT陶瓷的压电性能对于推动相关器件与系统的升级换代具有重要意义。

通过对陶瓷晶粒的织构化(即:将晶粒沿特定晶体学方向定向排列),充分发挥晶粒物理性质的各向异性,被认为是进一步提升PZT陶瓷压电性能的关键途径。然而,自上世纪90年代至今,人们始终无法制备出晶粒具有高度择优取向的PZT陶瓷,即:PZT织构陶瓷。具体来说,在陶瓷烧结过程中,PZT粉体会与传统钛酸盐微晶模板(BaTiO3或SrTiO3)发生严重的固相反应,导致微晶模板无法完成引导晶粒定向生长的任务,这也成为了困扰PZT陶瓷织构化工作的关键难题。

针对上述问题,西安交通大学电信学部电子学院李飞、徐卓教授团队与哈尔滨工业大学、澳大利亚新南威尔士大学、伍伦贡大学等单位合作,提出了通过“钝化”模板来实现PZT陶瓷高质量织构化的研究思路。一方面,研制出了一种新型锆钛酸钡[Ba(Zr, Ti)O3, BZT]模板,代替传统钛酸盐模板,提高了模板在PZT母体中的稳定性;另一方面,设计了Zr4+含量非均匀分布的PZT母体多层结构来代替传统的均匀结构,使籽晶模板首先在Zr4+含量较低的PZT母体中完成诱导晶粒定向生长的任务,在之后的晶粒生长和陶瓷致密化过程中,再通过Zr4+和Ti4+离子扩散获得组分均匀的PZT织构陶瓷。

基于上述方法,研究团队解决了几十年来PZT陶瓷无法被高质量织构化的学术难题,首次制备出了晶粒沿<001>高度择优取向的PZT织构陶瓷(图1a&b),在准同型相界附近获得了优异的压电、机电耦合性能(压电系数d33~700 pC/N、g33~90 mV·m/N、机电耦合系数k33~0.85),以及良好的温度稳定性(居里温度~360oC),突破了现有PZT陶瓷压电效应与居里温度的制约关系(图1c)。本项研究为诸多先进陶瓷的织构化工作提供了一种新的思路。研制出的高性能PZT织构陶瓷不但为高灵敏度传感器、换能器的性能提升带来了新的契机,同时也为研究PZT这类经典铁电体结构与性能关系提供了重要的基础材料。

西安交通大学为该论文的第一单位,西安交通大学电信学部电子科学与工程学院李景雷特聘研究员和李飞教授分别为论文的第一作者和通讯作者。哈尔滨工业大学常云飞教授和澳大利亚伍伦贡大学张树君教授为论文共同通讯作者。西安交通大学孙军院士、徐卓教授、丁向东教授、武海军教授、以及新南威尔士大学John Daniels副教授等为论文共同作者。本项研究工作得到了西安交通大学分析测试中心的大力支持,张杨高级工程师负责论文中的球差校正电镜实验和晶胞参数定量分析工作,任子君老师协助完成了陶瓷晶粒取向分析工作。

研究工作是在国家自然科学基金、国家重点研发计划、西安交通大学青年拔尖人才计划等项目的资助下完成的,同时得到了金属材料强度国家重点实验室和电子陶瓷与器件教育部重点实验室的大力支持。
 

SanWenYu

Captain
Registered Member
USTC created a new electrolyte material for all-solid-state lithium metal batteries that can run stably in room temporatures.

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A LaCl3-based lithium superionic conductor compatible with lithium metal​

Abstract​

Inorganic superionic conductors possess high ionic conductivity and excellent thermal stability but their poor interfacial compatibility with lithium metal electrodes precludes application in all-solid-state lithium metal batteries
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. Here we report a LaCl3-based lithium superionic conductor possessing excellent interfacial compatibility with lithium metal electrodes. In contrast to a Li3MCl6 (M = Y, In, Sc and Ho) electrolyte lattice
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, the UCl3-type LaCl3 lattice has large, one-dimensional channels for rapid Li+ conduction, interconnected by La vacancies via Ta doping and resulting in a three-dimensional Li+ migration network. The optimized Li0.388Ta0.238La0.475Cl3 electrolyte exhibits Li+ conductivity of 3.02 mS cm−1 at 30 °C and a low activation energy of 0.197 eV. It also generates a gradient interfacial passivation layer to stabilize the Li metal electrode for long-term cycling of a Li–Li symmetric cell (1 mAh cm−2) for more than 5,000 h. When directly coupled with an uncoated LiNi0.5Co0.2Mn0.3O2 cathode and bare Li metal anode, the Li0.388Ta0.238La0.475Cl3 electrolyte enables a solid battery to run for more than 100 cycles with a cutoff voltage of 4.35 V and areal capacity of more than 1 mAh cm−2. We also demonstrate rapid Li+ conduction in lanthanide metal chlorides (LnCl3; Ln = La, Ce, Nd, Sm and Gd), suggesting that the LnCl3 solid electrolyte system could provide further developments in conductivity and utility.

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中国科大开发出镧系金属卤化物基固态电解质新家族

近日,中国科学技术大学姚宏斌课题组、李震宇课题组与浙江工业大学陶新永课题组合作,设计开发出镧系金属卤化物基固态电解质新家族LixMyLnzCl3(Ln为镧系金属元素,M为非镧系金属元素)。得益于镧系金属元素的低电负性,以及金属氯化物良好的耐氧化性和可变形性,镧系金属卤化物基固态电解质可直接与锂金属负极和三元正极匹配,实现无任何电极修饰且室温可运行的全固态锂金属电池。相关研究成果以《A LaCl3-based lithium superionic conductor compatible with Li metal》为题,于4月5日发表在Nature杂志上。

金属卤化物固态电解质(LixMCl6, M为金属元素)因其宽电化学窗口、良好的室温电导率和不错的可变形性,展现出比氧化物/硫化物固态电解质更好的高电压氧化物正极适配性。2018年以来,基于Li3YCl6、Li3InCl6和Li3ScCl6等金属卤化物固态电解质的全固态锂电池实现了搭载钴酸锂、镍钴锰等4 V级正极的长循环,引起了广泛关注。然而,目前报道的大多数LixMCl6金属卤化物固态电解质采用易被还原的金属元素构建传导框架,导致对锂金属不稳定,只能采用高电位的锂铟合金,限制了高能量密度全固态锂金属电池的开发。同时,传统的LixMCl6晶格中氯离子是六方或立方紧密堆积,其空间体积较小,对锂离子的传导有一定限制,使其电导率大多在1 mS/cm。因此,开发对锂金属负极稳定的新型快离子导体框架结构是发展高比能全固态锂金属电池面临的关键挑战。

针对以上问题,团队成员发现,以LaCl3为代表的镧系金属卤化物LnCl3(Ln=La, Ce, Pr, Nd, Sm等)晶格中氯离子呈非紧密堆积形式,天然存在丰富的一维大尺寸孔道,适合锂离子的高速传输,并可通过镧空位形成连续的三维传导。分子动力学的模拟预测表明,具有独特非密堆积氯离子排列方式的LaCl3框架可实现13.8 mS cm-1的室温离子电导率(图1)。团队成员选择高价离子掺杂策略来制造镧空位,得益于大尺寸高速离子通道和相邻通道间超强的交换作用,优化的Li0.388Ta0.438La0.475Cl3表现出3.02 mS cm-1的高室温离子电导率和0.197 eV的低活化能,优于传统氧化物和最近报道的卤化物固态电解质,可与部分硫化物电解质相媲美(图2)。镧的低电负性和梯度界面层的形成赋予了LaCl3基电解质对锂金属良好的稳定性,组装的锂金属对称电池以0.2 mA cm-2的电流密度和1 mAh cm-2的面容量可稳定循环5000小时以上(图3)。基于此,组装的全固态锂金属原型电池无需负极垫层和正极包覆等额外的常用界面稳定手段,即可实现室温下百圈以上的循环(图4)。此外,团队成员还发现,镧系金属卤化物可容纳大量异种非镧系金属元素,且在此状态下仍能保持快离子传输的UCl3晶型结构特征。这个性质赋予了镧系金属卤化物框架极强的可拓展性,使镧系金属卤化物固态电解质LixMyLnzCl3在未来通过合理的元素设计,具备实现更高界面稳定性、更快离子传导和更廉价原料成本的巨大潜力。具备UCl3晶型特征结构的镧系金属卤化物固态电解质LixMyLnzCl3将成为如硫化物中LGPS结构、氧化物中LLZO结构的一个全新的电解质家族。

中国科学技术大学殷逸臣(博士后)、杨竞天(硕士生)、罗锦达(硕士生)和浙江工业大学卢功勋(博士)为本文的共同第一作者;中国科学技术大学姚宏斌教授、李震宇教授与浙江工业大学陶新永教授为本文的共同通讯作者。本工作得到中科院先导计划、国家自然科学基金委、稀土资源利用国家重点实验室开放基金、中国科学技术大学原创探索项目、中国科学技术大学“双一流”专项基金的资助。

本工作特别致谢北京大学深圳研究院肖荫果研究员、黄中垣博士,合肥微尺度物质科学国家研究中心的龚科老师、汪琳俊老师,高德英特(北京)科技有限公司应用科学家鞠焕新博士和上海同步辐射光源的文闻研究员在表征和分析方面的大力帮助与支持。合肥国轩高科动力能源有限公司的吴叶超、中国科学技术大学本科生王建平参与完成了本工作。
 
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