353 research outputs found
Regulating the Crystallization of FAPbI3-Based Perovskite with a Furan Substituted Ethylammonium Additive for Achieving Highly Efficient Solar Cells
No full textC.Z. and Q.Z. contributed equally to this work. This work was supported by the National Natural Science Foundation of China (No. U22A20142), the Hebei Province Key Research and Development Project (No. 20314305D), China Huaneng Group Co., Ltd Headquarters Science and Technology Project (HNKJ20-H88). H.Z. acknowledges the funding from the Shanghai Pujiang Program (22PJ1401200) and the National Natural Science Foundation of China (No. 52302229)
Real-Time Self-Optimization of Quantum Dot Laser Emissions During Machine Learning-Assisted Epitaxy
No full textTraditional methods for optimizing light source emissions rely on a time-consuming trial-and-error approach. While in situ optimization of light source gain media emission during growth is ideal, it has yet to be realized. In this work, in situ reflection high-energy electron diffraction (RHEED) is integrated with machine learning (ML) to correlate the surface reconstruction with the photoluminescence (PL) of InAs/GaAs quantum dots (QDs), which serve as the active region of lasers. A lightweight ResNet-GLAM model is employed for the real-time processing of RHEED data as input, enabling effective identification of optical performance. This approach guides the dynamic optimization of growth parameters, allowing real-time feedback control to adjust the QDs emission for lasers. InAs QDs on GaAs substrates are successfully optimized, with a 3.2-fold increase in PL intensity and a reduction in full width at half maximum (FWHM) from 36.69 to 28.17 meV. Automated, in situ self-optimized lasers with 5-layer InAs QDs achieved electrically pumped continuous-wave operation at 1240 nm with a low threshold current of 150 A cm−
2 at room temperature, an excellent performance comparable to samples grown through traditional manual multi-parameter optimization methods. These results mark a significant step toward intelligent, low-cost, and reproductive light emitters production.C.S. and W.Z. contributed equally to this work. This work was supported by the National Key R&D Program of China (Grant Nos. 2023YFB2805900, S.M.C.; 2021YFB2206500, C.Z.), National Natural Science Foundation of China (Grant No. 62274159, C.Z.), Beijing Natural Science Foundation (Grant Nos. L248103 and F251036, C.Z.), and CAS Project for Young Scientists in Basic Research (Grant No. YSBR\u2010056, C.Z.)
Enhanced Radiation Hardness of InAs/GaAs Quantum Dot Lasers for Space Communication
No full textSemiconductor lasers hold significant promise for space laser communication. However, excessive radiation in space can cause laser failures. In principle, quantum dot (QD) lasers are more radiation-resistant than traditional semiconductor lasers because of their superior carrier confinement and smaller active regions. However, the multifaceted nature of radiation effects on QDs result in ongoing controversies. In this work, comprehensive radiation tests under simulated space conditions on InAs/GaAs QDs and lasers is conducted to validate their performance. The results reveal that InAs/GaAs QDs with filling factors exceeding 50% exhibit enhanced radiation hardness. The linewidth enhancement factor (LEF) of well-designed QD lasers remains remarkably stable and nearly zero, even under proton irradiation at a maximum fluence of 7 × 1013 cm−2, owing to their intrinsic insensitivity to irradiation-induced defects. These QD lasers demonstrate an exceptional average relative intensity noise (RIN) level of −162 dB Hz−1, with only a 1 dB Hz−1 increase at the highest fluence, indicating outstanding stability. Furthermore, the lasers exhibit remarkable robustness against optical feedback, sustaining stable performance even under a feedback strength as high as −3.1 dB. These results highlight the critical advantages of QD lasers for space laser communication applications, where high reliability and resilience to radiation and environmental perturbations are essential.M.L., J.D., Z.J., and S.P. contributed equally to this work. This work was supported by the National Key R&D Program of China (Grant No. 2023YFB2805900, S.M.C.; 2021YFB2206500, C.Z.), National Natural Science Foundation of China (Grant No. 62274159, C.Z.; 62204072, J.N.D), Beijing Natural Science Foundation (Grant No. L248103, C.Z.), CAS Project for Young Scientists in Basic Research (Grant No. YSBR-056, C.Z.), and the Shenzhen Science and Technology Innovation Program (Grant No. JCYJ20240813104819027, J.N.D)
Roadmap for rechargeable batteries: present and beyond
No full textPublished online December 26, 2023Rechargeable batteries currently hold the largest share of the electrochemical energy storage market, and they play a major role in the sustainable energy transition and industrial decarbonization to respond to global climate change. Due to the increased popularity of consumer electronics and electric vehicles, lithium-ion batteries have quickly become the most successful rechargeable batteries in the past three decades, yet growing demands in diversified application scenarios call for new types of rechargeable batteries. Tremendous efforts are made to developing the next-generation post-Li-ion rechargeable batteries, which include, but are not limited to solid-state batteries, lithium–sulfur batteries, sodium-/potassium-ion batteries, organic batteries, magnesium-/zinc-ion batteries, aqueous batteries and flow batteries. Despite the great achievements, challenges persist in precise understandings about the electrochemical reaction and charge transfer process, and optimal design of key materials and interfaces in a battery. This roadmap tends to provide an overview about the current research progress, key challenges and future prospects of various types of rechargeable batteries. New computational methods for materials development, and characterization techniques will also be discussed as they play an important role in battery research.Sen Xin, Xu Zhang, Lin Wang, Haijun Yu, Xin Chang, Yu-Ming Zhao, Qinghai Meng, Pan Xu, Chen-Zi Zhao, Jiahang Chen, Huichao Lu, Xirui Kong, Jiulin Wang, Kai Chen, Gang Huang, Xinbo Zhang, Yu Su, Yao Xiao, Shu-Lei Chou, Shilin Zhang, Zaiping Guo, Aobing Du, Guanglei Cui, Gaojing Yang, Qing Zhao, Liubing Dong, Dong Zhou, Feiyu Kang, Hu Hong, Chunyi Zhi, Zhizhang Yuan, Xianfeng Li, Yifei Mo, Yizhou Zhu, Dongfang Yu, Xincheng Lei, Jianxiong Zhao, Jiayi Wang, Dong Su, Yu-Guo Guo, Qiang Zhang, Jun Chen and Li-Jun Wa
H2A.Z facilitates access of active and repressive complexes to chromatin in embryonic stem cell self-renewal and differentiation.
No full textSummaryChromatin modifications have been implicated in the self-renewal and differentiation of embryonic stem cells (ESCs). However, the function of histone variant H2A.Z in ESCs remains unclear. We show that H2A.Z is highly enriched at promoters and enhancers and is required for both efficient self-renewal and differentiation of murine ESCs. H2A.Z deposition leads to an abnormal nucleosome structure, decreased nucleosome occupancy, and increased chromatin accessibility. In self-renewing ESCs, knockdown of H2A.Z compromises OCT4 binding to its target genes and leads to decreased binding of MLL complexes to active genes and of PRC2 complex to repressed genes. During differentiation of ESCs, inhibition of H2A.Z also compromises RA-induced RARα binding, activation of differentiation markers, and the repression of pluripotency genes. We propose that H2A.Z mediates such contrasting activities by acting as a general facilitator that generates access for a variety of complexes, both activating and repressive
A Preclinical Model to Assess Intestinal Barrier Integrity Using Canine Enteroids and Colonoids
No full textAuthor Contributions:
Conceptualization, V.G., K.A. and J.P.M.; Data curation, V.G., A.R., C.Z., H.W., A.L., T.A., D.K.S. and D.K.M.; Formal analysis, M.P.C., V.G., V.L., D.D.-R. and C.Z.; Funding acquisition, K.A. and J.P.M.; Investigation, V.G., A.R., C.Z., H.W., T.A. and D.K.S.; Methodology, V.G., V.L., D.D.-R., A.R., C.Z., D.L., S.M., H.W., T.A. and D.K.M.; Resources, M.M.M. and K.A.; Supervision, K.A. and J.P.M.; Validation, V.G. and C.Z.; Visualization, V.G.; Writing—original draft, V.G.; Writing—review and editing, M.P.C., C.Z., K.P., D.K.M., K.A. and J.P.M. All authors have read and agreed to the published version of the manuscript.While two-dimensional (2D) cell cultures, such as Caco-2 and Madin–Darby canine kidney (MDCK) cells are widely used in a variety of biological models, these two-dimensional in vitro systems present inherent limitations in replicating the complexities of in vivo biology. Recent progress in three-dimensional organoid technology has the potential to address these limitations. In this study, the characteristics of conventional 2D cell culture systems were compared to those of canine intestinal organoids (enteroids, ENT, and colonoids, COL). Light microscopy and transmission electron microscopy were employed to evaluate the microanatomy of ENT, COL, Caco-2, and MDCK cell monolayers, while transepithelial electrical resistance (TEER) values were measured to assess monolayer integrity. The TEER values of canine ENT monolayers more closely approximated reported TEER values for human small intestines compared to Caco-2 and MDCK monolayers. Additionally, canine ENT demonstrated greater monolayer stability than Caco-2 and MDCK cells. Notably, while all systems displayed desmosomes, canine ENT and COL exclusively produced mucus. These findings highlight the potential of the canine organoid system as a more biologically relevant model for in vitro studies, addressing the limitations of conventional 2D cell culture systems.Simple Summary:
Immortalized cell lines are often used to model biological systems, such as the intestinal epithelium. Compared to immortalized cell lines, which are composed of identical cell clones, organoids derived from adult stem cells may represent a more accurate biological model, since they can differentiate into specialized intestinal epithelial cell types. In this study, we isolated adult stem cells from dog intestinal samples, which can be obtained with minimally invasive methods. These adult intestinal stem cells were grown into three-dimensional organoids, which recapitulate the superficial layers (epithelium) of the original tissue. The intestinal organoids were examined under a microscope to assess their similarity to the original tissue, then cultured and compared to two immortalized cell lines. The organoids had features similar to intestinal tissue, such as mucus production. In the 2D cell culture system, the organoids formed a more consistent layer than conventional cell lines, demonstrating similar integrity to that of the human intestine. These findings suggest that organoid cultures derived from dog intestinal adult stem cells can effectively be utilized in traditional cell culture systems.National Science Foundation (NSF)Depto. de Medicina y Cirugía AnimalFac. de VeterinariaTRUEpu
Biocrusts regulate the effect of rainfall pulses on soil respiration at different temporal scales on the Loess Plateau
No full textRainfall pulses are one of the most important factors affecting soil respiration, especially in drylands where water is limited. Biocrusts are also crucial in dryland ecosystems and play important roles in regulating soil carbon cycling. However, it is unclear how biocrusts mediate the effects of rainfall pulses on soil respiration. Using continuous field monitoring, we explored whether and how different types of biocrusts (including cyanobacteria-, lichen- and moss-dominated biocrusts) modulate the effects of precipitation on soil respiration under drying-rewetting cycles at event and seasonal scales. We found that soil respiration was induced after rainfall pulses, especially at different types of biocrusted microsites. The increments of soil respiration during drying-rewetting cycles were greater in the moss-dominated biocrusts than in the bare soil, which suggested that the response of soil respiration to drying-rewetting cycles was increased by moss-dominated biocrusts. The length of the dry period, number of cycles, intensity of the dry period and frequency of rewetting affected the magnitude of soil respiration at event scales. However, when we analysed all of the drying-rewetting cycles together, that is, at the seasonal scale, the soil temperature was the driving factor affecting the maximum soil respiration after rainfall pulses. Therefore, soil temperature, rather than soil moisture, is the key factor regulating the response of soil respiration to drying-rewetting cycles at the seasonal scale. This study highlights the importance of temperature in regulating soil respiration under drying-rewetting cycles, and the regulatory factors of soil respiration vary at different temporal scales.This study was supported by the National Natural Science Foundation of China (grant number 31901225, awarded to C.G., and grant number 32125028, awarded to C.Z.) and the Science and Technology Project of Gansu (grant number 18JR2RA009, awarded to C.Z.). N.C. was supported by the Fundamental Research Funds for the Central Universities (grant number lzujbky-2021-ey16)
A new perspective on the icons of the C. Z. monogrammist : a contribution to the research on Orthodox painting on the Russian-Ukrainian borderlands
No full textArtykuł dotyczy twórczości monogramisty C.Z., malarza ikon, działającego około połowy wieku XVII na terenach pogranicza polsko-słowackiego. Analiza dzieł zdradza ważne tajniki jego warsztatu. Ukazuje wyraźnie, jak różnymi środkami stylistycznymi posługiwał się, malując formy małe i duże. W tych pierwszych przeważają wartości graficzne: linie i plamy barwne kładzione są szybko, na ciemną podmalówkę, a silne kontrasty między cieniami i rozświetleniami nadają twarzom surowy wyraz. Postaci na ikonach dużych malowane są miękko, a plastyczność twarzy modelowana walorowo. I choć ciemny kontur zamyka tu każdy niemal element, to przewaga rysów malarskich jest zdecydowana. Dopiero analiza tej drugiej maniery pozwala odkryć prawdziwe umiejętności tego malarza i ocenić je stosunkowo wysoko, na tle innych pracujących w XVII wieku na Łemkowszczyźnie warsztatów. W wyniku badań monogramiście C.Z. można przypisać ikony: Matki Boskiej Hodegetrii, Chrystusa Pantokratora, Archanioła Michała oraz Dymitra Sołuńskiego w Muzeum Parafialnym w Grybowie, ikony świąteczne z Berestu i grupę Ukrzyżowania w Bereście, grupę Ukrzyżowania i Chrystusa Pantokratora z Bielanki, Ostatnią Wieczerzę z Czyrnej, carskie wrota z Matysowej i być może Matki Boskiej Hodegetrii z Klimkówki.The article describes the icons of an artist identified only by the monogram
C.Z. – a painter, who worked around the mid-17th century in the Polish-Slovak border areas. An analysis of his works shows the important details of his painting techniques. One can see very clearly how he used various stylistic means to paint small forms and large forms. The former are dominated by graphical values: lines and patches of colour are quickly laid on the dark underpain, and a strong contrast between shadows and highlights produces the strict expressions of the faces. Big forms on large icons are painted softly, and the plasticity of the face is modelled with hight-contrast light. Although almost every element here is enclosed in the dark outline, painting features dominate. Only an analysis of the latter elements of the painting style of the artist allow us to discover the real skills of this painter and assess them relatively well, in comparison with another painters working in the 17th century in the Lemko region. As a result of the research one can say, that monographer, C.Z. was the author
of the following icons: The Mother of God Hodegetria, Christ Pantocrator, the Archangel Michael and Demetrios of Thessalonike in the Parish Museum in Grybow, Feast Days from Berest and a Group of the Crucifixion in Berest, a Group of the Crucifixion and Christ Pantocrator from Bielanka, The Last Supper from Czyrna, the Royal Doors from Matysowa and maybe The Mother of God Hodegetria from Klimkówka
Kinematic Modeling and Deformation Mechanics in Shot Peening of Functional Ceramics
No full textAbstractThe applications of ceramics are limited by their brittle nature and low reliability. Recent studies show that compressive residual stress can be introduced in ceramics by shot peening, which can improve the contact strength and fatigue of ceramics. However, the formation mechanism of residuals stress has not been investigated yet. In this study, a pressure dependent plasticity model has been incorporated into a FE model of shot peening to shed light on the residual stress formation mechanism. Since shot velocity is the key process parameter to dominate the impact energy which determines the deformation state of surface material and the resultant residual stress, a new kinematic model of shots has also been developed by incorporating air drag and travel distance inside and outside the peening nozzle. The results have shown that the kinematic model can be used to predict shot velocity. The FE model provided an insightful understanding of the residual stress formation mechanisms
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