News on China's scientific and technological development.

ansy1968 said:

@taxiya bro is that an ICRD logo? so ICRD had JV or coordination with HLMC? IF true, then Huawei 14nm 3D chiplet may have been FAB by HLMC aside from SMIC. Now I think Huawei FAB ambitions maybe limited to 3 FABS (Shanghai, Shenzhen and Wuhan) as they utilized more domestic alternative (FAB are costly to build and operate).

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taxiya said:

The second photo 先进工艺引导线(trail introduction line) is ICRD. ICRD is a research entity, HLMC is a manufacturer. As stated by ICRD, it is open to serve semiconductor manufacturer. Since both are state driven enterprises, it is only natural that they work hand in hand. How the collaboration is done, JV or HLMC invest in ICRD, is not important.

Can't comment on Huawei, but the option is certainly there.

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BoraTas said:

Their loss

Processor performance is an extremely multifactorial thing. Multi-node computer system performance is even more multifactorial since communication throughput and latency between processors and nodes become important as well.

Starting around 2005, computer performance in terms of instructions per clock per core, and clock speed has mostly stalled. Since then the main method to increase computer performance is increasing parallelism. This is achieved by more cores, more CPUs and even more nodes. Decreasing the node size used to enable more advanced architectures and higher clock speeds. Now it mostly doesn't and that means unless the difference is extreme you can make up for it with just bigger and more chips. SMIC 12 nm and N+1 (roughly 8 nm equivalent) are more than enough for competing with computers using TSMC's 5 nm node if the Chinese government is willing to pay the price.
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High-performance photocatalytic nonoxidative conversion of methane to ethane and hydrogen by heteroatoms-engineered TiO2​

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Nonoxidative coupling of methane (NOCM) is a highly important process to simultaneously produce multicarbons and hydrogen. Although oxide-based photocatalysis opens opportunities for NOCM at mild condition, it suffers from unsatisfying selectivity and durability, due to overoxidation of CH4 with lattice oxygen. Here, we propose a heteroatom engineering strategy for highly active, selective and durable photocatalytic NOCM. Demonstrated by commonly used TiO2 photocatalyst, construction of Pd–O4 in surface reduces contribution of O sites to valence band, overcoming the limitations. In contrast to state of the art, 94.3% selectivity is achieved for C2H6 production at 0.91 mmol g–1 h–1 along with stoichiometric H2 production, approaching the level of thermocatalysis at relatively mild condition. As a benchmark, apparent quantum efficiency reaches 3.05% at 350 nm. Further elemental doping can elevate durability over 24 h by stabilizing lattice oxygen. This work provides new insights for high-performance photocatalytic NOCM by atomic engineering.

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甲烷作为一种重要的碳基小分子，在自然界分布广泛，是天然气、页岩气、可燃冰、沼气等的主要成分。迄今为止，甲烷的使用仍以燃烧为主，导致排放出大量的二氧化碳。甲烷作为化工原料主要用于合成氨、甲醇及其衍生物，但其用量仅占天然气消耗量的5%-7%。虽然甲烷储量远远超过石油储量，但作为化工原料其开发程度远无法与石油相比。如何将储量巨大的甲烷资源转化为具有更高经济附加值的燃料或化工产品，具有重要的科学意义和应用前景。太阳能作为最为丰富和清洁的能源，可通过光催化方式在温和条件下驱动甲烷转化为多碳燃料或化学品。近年来，中国科学技术大学熊宇杰教授和龙冉教授研究团队发展了一系列光/光电催化方法，实现了甲烷高选择性转化制乙烷、乙烯和乙二醇

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近日，熊宇杰教授和龙冉教授研究团队与中国科学技术大学杨金龙院士团队付岑峰副研究员、南京大学邹志刚院士团队姚颖方教授合作，发展了光催化甲烷无氧偶联（NOCM）方法，实现了高选择性制备乙烷和氢气，效率达到中温热催化NOCM水平，发表在《自然×通讯》期刊

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光催化NOCM可以在温和条件下同时获取多碳烃类和氢气，是一条极具吸引力的途径。氧化物半导体凭借其良好的光利用率和优秀的氧化能力，被广泛应用于光催化NOCM的研究。然而，用于活化甲烷的光生空穴主要聚集在氧化物半导体的晶格氧位点，使得甲烷极易被晶格氧原子过度氧化产生一氧化碳、二氧化碳等副产物。在该工作中，熊宇杰和龙冉团队提出通过单原子配位负载的方法来调控光催化剂的价带电子结构，以得到具有高活性、选择性和稳定性的NOCM光催化剂。以最常见的二氧化钛为例，在其表面构建的“钯-氧”配位结构，可以将光生空穴聚集在“钯-氧”配位结构单元上，从而在提高光催化NOCM性能的同时降低甲烷的过度氧化程度。基于该策略，实现了94.3%乙烷选择性、0.91 mmol g-1 h-1乙烷产率以及等化学计量比的氢气产物。进一步地，通过元素掺杂的方法，提高了催化剂中晶格氧的稳定性，进而延长催化性能的稳定性。该工作为发展高效光催化NOCM催化剂提供了新的思路。

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Extremely fast-charging lithium ion battery enabled by dual-gradient structure design​

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Extremely fast-charging lithium-ion batteries are highly desirable to shorten the recharging time for electric vehicles, but it is hampered by the poor rate capability of graphite anodes. Here, we present a previously unreported particle size and electrode porosity dual-gradient structure design in the graphite anode for achieving extremely fast-charging lithium ion battery under strict electrode conditions. We develop a polymer binder–free slurry route to construct this previously unreported type particle size-porosity dual-gradient structure in the practical graphite anode showing the extremely fast-charging capability with 60% of recharge in 10 min. On the basis of dual-gradient graphite anode, we demonstrate extremely fast-charging lithium ion battery realizing 60% recharge in 6 min and high volumetric energy density of 701 Wh liter−1 at the high charging rate of 6 C.

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能量密度、功率密度是评价电池系统的两个重要参数。能量密度决定着单位质量/体积下可以储存的能量大小，而功率密度则决定着电池充放的倍率。理想状态下，这两项参数越高，锂离子电池性能越好。然而，高能量密度与快充性能是一对矛盾，是一个“此起彼伏”的过程。

卢磊磊说，“高能量密度通常意味着电池单体活性物质载量比较高，电极比较厚，从而具有较长的锂离子传输路径，限制充放电倍率。”

因此，为提高石墨负极的倍率性能，传统的策略通常是将石墨电极做到多孔或变薄。 “但是，这些方法往往就会牺牲所制备电池的能量密度。”卢磊磊坦言。

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在粒子级理论模型中，研究人员按照石墨颗粒大小的顺序重新“排队”，同时调整电极孔隙率大小分布。具体表现为，越接近电池顶部的石墨颗粒更小，孔隙率更高，越接近底部颗粒更大，孔隙率更低。

“我们将这种结构称之为双梯度电极。”卢磊磊说，模拟计算结果表明，在大电流密度充电条件下，这种新结构相对于传统的随机均质电极以及单梯度电极，展现出了优异的快充性能。

理想的结构模型已找到，接下来就是如何在电极中实现。

传统的电极制备方法中，由于浆料黏度很高，制备的石墨浆料稳定，不易发生沉降。因此制备出的电极，包括石墨颗粒大小和孔隙率大小通常都是均匀分布。卢磊磊说，“就像速溶奶粉，取任何一部分都是均质的。”

如何构筑一种“异质”结构？研究团队开发了一种低粘度无聚合物粘结剂浆料自组装技术，混合铜包覆的石墨负极颗粒以及铜纳米线于乙醇溶液中制成浆料，利用不同尺寸颗粒石墨在浆料中沉降速度差异性，成功构建出模拟计算优化的双梯度结构，得到电极。

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研究人员发现，基于这种新型双梯度石墨负极材料制备出的锂离子电池分别在5.6分钟和11.4分钟从零充电到60%和80%，同时保持高能量密度。

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“距离产业化还有一定距离。”卢磊磊坦言，比如目前实验室的制备方法很难实现大规模生产，双梯度结构的设计很难保持电极的一致性。

“目前，团队正逐步解决这些问题。希望有朝一日这种更高效的电池可以为电动汽车提供动力。”卢磊磊说。

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Fabrication of Large Aerogel-Like Carbon/Carbon Composites with Excellent Load-Bearing Capacity and Thermal-Insulating Performance at 1800 °C​

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Carbon aerogels (CAs) are attractive candidates for the thermal protection of aerospace vehicles due to their excellent thermostability and thermal insulation. However, the brittleness and low mechanical strength severely limits their practical applications, and no significant breakthroughs in large CAs with a high strength have been made. We report a high-pressure-assisted polymerization method combined with ambient pressure drying to fabricate large, strong, crack-free carbon/carbon (C/C) composites with an excellent load-bearing capacity, thermal stability, and thermal insulation. The composites are comprised of an aerogel-like carbon matrix and a low carbon crystallinity fiber reinforcement, featuring overlapping nanoparticles, macro-mesopores, large particle contact necks, and strong fiber/matrix interfacial bonding. The resulting C/C composites with a medium density of 0.6 g cm–3 have a very high compressive strength (80 MPa), in-plane shear strength (20 MPa), and specific strength (133 MPa g–1 cm3). Moreover, the C/C composites of 7.5–12.0 mm in thickness exposed to an oxyacetylene flame at 1800 °C for 900 s display very low back-side temperatures of 778–685 °C and even better mechanical properties after the heating. This performance makes the composites ideal for the ultrahigh temperature thermal protection of aerospace vehicles where both excellent thermal-insulating and load-bearing capacities are required.

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近日，中国科学院金属研究所热结构复合材料团队采用高压辅助固化-常压干燥技术，通过基体微结构控制、纤维-基体协同收缩、原位界面反应制备出耐超高温隔热-承载一体化轻质碳基复合材料。

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在此基础上，该团队以工业酚醛树脂为前驱体，采用高沸点醇类为造孔剂并辅以高压固化，促使有机网络的均匀生长及大接触颈、层次孔的生成，实现了骨架本征强度的提升，同时采用与前驱体有机气凝胶匹配性好的酚醛纤维作为增强体，通过纤维/基体界面原位反应，实现了炭化过程中基体和纤维的协同收缩及纤维/基体界面强的化学结合，最终获得了大尺寸、无裂纹的碳纤维增强类CAs复合材料。

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上述隔热-承载一体化轻质碳基复合材料作为刚性隔热材料在多个先进发动机上装机使用，为型号发展提供了关键技术支撑。

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Direct connected experimental research on hydrocarbon-fueled rotating detonation​

PopularScience said:

Direct connected experimental research on hydrocarbon-fueled rotating detonation​

Abstract: Direct connected tests of rotating detonation were performed with ethylene and room-temperature kerosene adopted as fuel. The corresponding flight velocity is Ma 5, and the Mach number is 2.5 at the isolator entrance. Results show that the rotating detonation wave was sustained after initiation with the equivalent ratio of ethylene ranging from 0.43 to 0.99. The propagation frequency of detonation waves is 5.32–6.42 kHz, with a propagation cycle of 0.156–0.188 ms. As the equivalent ratio increases, the propagation velocity of the detonation wave and the pressure in the detonation combustor increase almost linearly. While the averaged pressure peaks of the dynamic pressure（PCB pressure sensor） first increase and then decrease. The pressure at the isolator exit also increases under a higher equivalent ratio, but the velocity remains unchanged at Ma 2.5. When the equivalent ratio of kerosene was about 0.70, the rotating detonation wave was also sustained.

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