Precipitation variations of Longxi, northeast margin of Tibetan Plateau since AD 960 and their relationship with solar activity

International audienceThe precipitation variations of Longxi area, northeast margin of the Tibetan Plateau since AD 960 are reconstructed from Chinese historical documentary records. These records show that since AD 960, the precipitation of Longxi decreased and reached the lowest level at the end of the 17th and the 18th centuries. After this period, the precipitation gradually increased. The three short wet periods of Longxi in the last millennium were: from the end of the 10th century to the early years of the 11th century, from the end of the 12th century to the early years of the 13th century and during the first half of the 20th century. The precipitation variations coincide well with variations of the Northern Hemisphere temperature and the atmospheric 14C concentration, as well as the averaged 10Be concentration and the reconstructed solar modulation record which show that solar activity may be an important driving force of the precipitation variations of Longxi on multi-decadal to centennial scales during the last millennium. Solar activity controls the motion of the north edge of the Asian summer monsoon by affecting the Asia summer monsoon intensity, the East Asian winter monsoon intensity and the locations of westerlies, thus further dominating precipitation variations of Longxi. Synchronous variations of Longxi precipitation and Northern Hemisphere temperature may also be ascribed to the same control of solar activity

Indian monsoon variability on millennial-orbital timescales

The Indian summer monsoon (ISM) monsoon is critical to billions of people living in the region. Yet, significant debates remain on primary ISM drivers on millennial-orbital timescales. Here, we use speleothem oxygen isotope (δ18O) data from Bittoo cave, Northern India to reconstruct ISM variability over the past 280,000 years. We find strong coherence between North Indian and Chinese speleothem δ18O records from the East Asian monsoon domain, suggesting that both Asian monsoon subsystems exhibit a coupled response to changes in Northern Hemisphere summer insolation (NHSI) without significant temporal lags, supporting the view that the tropical-subtropical monsoon variability is driven directly by precession-induced changes in NHSI. Comparisons of the North Indian record with both Antarctic ice core and sea-surface temperature records from the southern Indian Ocean over the last glacial period do not suggest a dominant role of Southern Hemisphere climate processes in regulating the ISM variability on millennial-orbital timescales

Analyzing and visualizing dissemination patterns and emerging trends on typo-morphology studies in China

Beyond the long development history from Conzen's morphology to Muratori and Caniggia's typology in Europe, the attention on understanding the continuity of urban form from Chinese scholars are emerging noticeably. It is worth to mention that although there are several articles about the application of typo-morphology into the Chinese context, the work of the literature review is apparently waiting for a more comprehensive and objective study. Thus, a better collecting and demonstrating of the typo-morphology works of literature is urgently requested by tracing the evolution process and dissemination pattern in the Chinese academic community. This study establishes a quantitative study and visual survey by offering abundant visualized graphics about citations and authorship patterns, and relevant bibliography based on the database of Web of Science (WoS) and China National Knowledge Infrastructure (CNKI) by utilizing Citespace. It provides an in-depth analysis of the current theoretical background aiming to inspire further typo-morphological research and practices in the Chinese context and beyond

Modeling and Controller Design for the Air-to-Air Missile Uncertain System

The guidance and control problem of the air-to-air missile system is studied. A nonlinear, coupling dynamic model of the air-to-air missile with six degrees of freedom is investigated, and a uncertain control system is proposed according to some assumptions and simplifications. Then, based on Lyapunov stability theory, a Lyapunov function is employed, and a controller is designed for the air-to-air missile. Numerical simulations show that the control system proves the correctness and has preferably tracking performance and illustrate the effectiveness of the proposed controller

Adaptive Vibration Control for Cable-Bridge Coupled Uncertain Nonlinear System

Considering buffeting loading on the structure, technique of adaptive vibration control for long-span cable-bridge structure is developed. Model of vibration control for uncertain nonlinear systems of long-span cable-bridge structure is established; buffeting loading systems of long-span bridge structure is created by weighted amplitude wave superposition method. In order to depress buffeting loading influence of the wind-induce vibration for the structure and improve the robust performance of the vibration control, based on the semi-active vibration control devices and using adaptive control approach, an adaptive vibration controller and adaptive control laws for the uncertain parameters are designed. Numerical simulation results illustrate the effectiveness of the proposed technique

Improving the sensitivity of a near-infrared nanocomposite photodetector by enhancing trap induced hole injection

We report the enhancement of the photoconductive gain of nanocomposite near-infrared photodetectors by a zinc oxide nanoparticles (ZnO NPs) rich surface at the nanocomposite/cathode interface. An argon plasma etching process was used to remove polymer at the surface of nanocomposite films, which resulted in a ZnO NPs rich surface. The other way is to spin-coat a thin layer of ZnO NPs onto the nanocomposite layer. The ZnO NPs rich surface, which acts as electron traps to induce secondary hole injection under reverse bias, increased hole injection, and thus the external quantum efficiency by 2–3 times. The darkcurrent declined one order of magnitude simultaneously as a result of etching the top nanocomposite layer. The specific detectivity at 800 nm was increased by 7.4 times to 1.11x1010 Jones due to the simultaneously suppressed noise and enhanced gain

Analog Beamforming Enabled Multicasting: Finite-Alphabet Inputs and Statistical CSI

The average multicast rate (AMR) is analyzed in a multicast channel utilizing analog beamforming with finite-alphabet inputs, considering statistical channel state information (CSI). New expressions for the AMR are derived for non-cooperative and cooperative multicasting scenarios. Asymptotic analyses are conducted in the high signal-to-noise ratio regime to derive the array gain and diversity order. It is proved that the analog beamformer influences the AMR through its array gain, leading to the proposal of efficient beamforming algorithms aimed at maximizing the array gain to enhance the AMR.Comment: 5 page

Improving the sensitivity of a near-infrared nanocomposite photodetector by enhancing trap induced hole injection

We report the enhancement of the photoconductive gain of nanocomposite near-infrared photodetectors by a zinc oxide nanoparticles (ZnO NPs) rich surface at the nanocomposite/cathode interface. An argon plasma etching process was used to remove polymer at the surface of nanocomposite films, which resulted in a ZnO NPs rich surface. The other way is to spin-coat a thin layer of ZnO NPs onto the nanocomposite layer. The ZnO NPs rich surface, which acts as electron traps to induce secondary hole injection under reverse bias, increased hole injection, and thus the external quantum efficiency by 2–3 times. The darkcurrent declined one order of magnitude simultaneously as a result of etching the top nanocomposite layer. The specific detectivity at 800 nm was increased by 7.4 times to 1.11x1010 Jones due to the simultaneously suppressed noise and enhanced gain

GCformer: An Efficient Framework for Accurate and Scalable Long-Term Multivariate Time Series Forecasting

Transformer-based models have emerged as promising tools for time series forecasting. However, these model cannot make accurate prediction for long input time series. On the one hand, they failed to capture global dependencies within time series data. On the other hand, the long input sequence usually leads to large model size and high time complexity. To address these limitations, we present GCformer, which combines a structured global convolutional branch for processing long input sequences with a local Transformer-based branch for capturing short, recent signals. A cohesive framework for a global convolution kernel has been introduced, utilizing three distinct parameterization methods. The selected structured convolutional kernel in the global branch has been specifically crafted with sublinear complexity, thereby allowing for the efficient and effective processing of lengthy and noisy input signals. Empirical studies on six benchmark datasets demonstrate that GCformer outperforms state-of-the-art methods, reducing MSE error in multivariate time series benchmarks by 4.38% and model parameters by 61.92%. In particular, the global convolutional branch can serve as a plug-in block to enhance the performance of other models, with an average improvement of 31.93\%, including various recently published Transformer-based models. Our code is publicly available at https://github.com/zyj-111/GCformer