Design and implementation of resilient attitude estimation algorithms for aerospace applications

Satellite attitude estimation is a critical component of satellite attitude determination and control systems, relying on highly accurate sensors such as IMUs, star trackers, and sun sensors. However, the complex space environment can cause sensor performance degradation or even failure. To address this issue, FDIR systems are necessary. This thesis presents a novel approach to satellite attitude estimation that utilizes an InertialNavigation System (INS) to achieve high accuracy with the low computational load. The algorithm is based on a two-layer Kalman filter, which incorporates the quaternion estimator(QUEST) algorithm, FQA, Linear interpolation (LERP)algorithms, and KF. Moreover, the thesis proposes an FDIR system for the INS that can detect and isolate faults and recover the system safely. This system includes two-layer fault detection with isolation and two-layered recovery, which utilizes an Adaptive Unscented Kalman Filter (AUKF), QUEST algorithm, residual generators, Radial Basis Function (RBF) neural networks, and an adaptive complementary filter (ACF). These two fault detection layers aim to isolate and identify faults while decreasing the rate of false alarms. An FPGA-based FDIR system is also designed and implemented to reduce latency while maintaining normal resource consumption in this thesis. Finally, a Fault Tolerance Federated Kalman Filter (FTFKF) is proposed to fuse the output from INS and the CNS to achieve high precision and robust attitude estimation.The findings of this study provide a solid foundation for the development of FDIR systems for various applications such as robotics, autonomous vehicles, and unmanned aerial vehicles, particularly for satellite attitude estimation. The proposed INS-based approach with the FDIR system has demonstrated high accuracy, fault tolerance, and low computational load, making it a promising solution for satellite attitude estimation in harsh space environment

Comparing the contribution of visible-light irradiation, gold nanoparticles, and titania supports in photocatalytic nitroaromatic coupling and aromatic alcohol oxidation

Under visible-light irradiation, gold nanoparticles (Au NPs) supported by titania (TiO₂) nanofibers show excellent activity and high selectivity for both reductive coupling of nitroaromatics to corresponding azobenzene or azoxylbenzene and selective oxidation of aromatic alcohols to corresponding aldehydes. The Au NPs act as active centers mainly due to their localized surface plasmon resonance (LSPR) effect. They can effectively couple the photonic energy and thermal energy to enhance reaction efficiency. Visible-light irradiation has more influence on the reduction than on the oxidation, lowering the activation energy by 24.7 kJ mol⁻¹ and increasing the conversion rate by 88% for the reductive coupling, compared to merely 8.7 kJ mol⁻¹ and 46% for the oxidation. Furthermore, it is found that the conversion of nitroaromatics significantly depends on the particle size and specific surface area of supported Au NPs; and the catalyst on TiO₂(B) support outperforms that on anatase phase with preferable ability to activate oxygen. In contrast, for the selective oxidation, the effect of surface area is less prominent and Au NPs on anatase exhibit higher photo-catalytic activity than other TiO₂ phases. The catalysts can be recovered efficiently because the Au NPs stably attach to TiO₂ supports by forming a well-matched coherent interface observed via high-resolution TEM

Extension of summer (June–August) temperature records for northern Inner Mongolia (1715–2008), China using tree rings

This paper presents a spatially and temporally improved reconstruction of mean summer (June–August) temperature derived from tree-ring width data of Dahurian larch (Larix gmelinii Rupr.) from the northern Great Xing'an Mountains, Northeast China. Three new chronologies were added to the original 2011 reconstruction, and the reconstruction extended back to AD 1715. The reconstruction was generated using a simple linear regression method, verified by independent meteorological data, and accounts for 47.0% of the actual temperature variance during the common period (1957–2008). The reconstruction captures decadal and century-scale regional temperature variability, such as cold decades (1940s, 1930s, 1790s, 1950s and 1850s), warm decades (2000s, 1870s, 1750s, 1980s and 1840s), a cold half-century (ca. 1750–1799), and a warm half-century (ca. 1900–1949). It also reveals slightly higher frequency of cold years (20.4%) than warm years (18.0%), and a recent warming trend. Compared to the original 2011 reconstruction, this reconstruction has lower inter-annual temperature variability, high explained variance and high representativeness of regional climate. The reconstruction also correlates with the East Asian Monsoon and the Pacific Ocean signals, and indicates the feasibility of using tree rings from high latitude Northeast China to reconstruct summer temperature in permafrost forest environments

Response of radial growth to warming and CO2 enrichment in southern Northeast China: a case of Pinus tabulaeformis

The southern part of northeast China has experienced a marked warming and drying climate. We provide dendrochronological evidence for atmospheric CO2 fertilization and the impacts of warming on Chinese pine (Pinus tabulaeformis) growth. The results of this study show that increased temperature has a negative effect on pine growth during a major part of the growing season and a weakly positive effects on growth during the remaining portion of the year. The monthly temperatures explain ca. 20 % of the total variance in the annual radial growth of Chinese pine from 1901 to 2009. An increase of approximately 3–5 °C is the maximum that Chinese pine can tolerate in this region with an annual rainfall of 500–700 mm. Our results suggest a that there is a proportional response to warming only up to a maximum of 1 °C warming, and indicate the complexities of succession in forest ecosystems in terms of adaptation and evolution in local pine populations under a rapid warming condition. In addition, increasing atmospheric CO2 concentrations have a positive effect on tree growth. This effect can be detected with conventional dendrochronological methods

Tree-ring based precipitation variability since AD 1828 in northwestern Liaoning, China

A 183-year record of total precipitation from September to current July was reconstructed using tree rings from Chinese pine (Pinus tabulaeformis) to explore regional moisture variations in northwestern Liaoning province. The reconstruction accounts for 35.4% of the total variance of the instrumental precipitation from 1957 to 2010. The reconstruction shows eleven persistent dry periods (e.g. 1856–1866, 1886–1891, 1898–1905), and eleven persistent wet periods (e.g. 1835–1855, 1867–1878, 1892–1897). Spectral analysis of the reconstruction shows several significant spectral peaks in the ca. 2–4-year periodicity band, suggesting inter-annual variability of El Niño-Southern Oscillation (ENSO). The precipitation reconstruction shows correlations related to the East Asian Monsoon and possible teleconnection of regional moisture variations to Pacific Ocean signals, such as El Niño and La Niña

USP6-associated soft tissue tumors with bone metaplasia: Clinicopathologic and genetic analysis and the identification of novel USP6 fusion partners

IntroductionAmong those tumors with consistent USP6 rearrangement, some arise from soft tissue and show bone metaplasia, including myositis ossificans (MO), fibro-osseous pseudotumor of digits (FOPD), soft tissue aneurysmal bone cyst (ST-ABC) and fasciitis ossificans (FO). These lesions are easily confused with malignancies because they show a rapid growth rate and brisk mitoses. Here, we aim to clarify the clinicopathologic and genetic characteristics of this entity and analyze the correlations among the different subtypes in one of the largest cohorts.Materials and MethodsThe clinicopathologic features of 73 cases of MO, FOPD, ST-ABC and FO diagnosed at West China Hospital, Sichuan University from January 2010 to December 2021 were retrospectively analyzed. Forty-three undecalcified samples were analyzed by systematic genetic studies, including fluorescence in situ hybridization (FISH), reverse transcription polymerase chain reaction (RT-PCR), Sanger sequencing and next-generation-based sequencing were performed.ResultsThis series included 40 males and 33 females aged 2 to 80 years old (median: 31 years). FOPD occurred in extremal soft tissue, while lower extremities (38/58, 65.5%) were the most commonly involved lesions in the other three subgroups. Histologically, proliferative myofibroblasts/fibroblasts with varying degrees of osteoid tissue were present. Fluorescence in situ hybridization (FISH) results indicated that 22 cases (22/27, 81.5%) were positive for USP6 rearrangement, and 5 cases were negative. Among those cases with positive FISH results, 18 underwent reverse transcription-polymerase chain reaction (RT-PCR) detection that successfully detected common USP6 fusion types. Thirteen cases showed COL1A1::USP6 fusion, one showed MYH9::USP6 fusion, and 4 were negative for common fusion types. Next-generation-based sequencing technology was performed on two lesions with negative RT–PCR results and novel fusion partners SNHG3 and UBE2G1 were discovered.ConclusionsOur findings revealed that COL1A1 is the most common fusion partner in this entity, unlike primary aneurysmal bone cysts and nodular fasciitis. Notably, we believed that FO may demonstrate more similar clinicopathologic and genetic manifestations with MO/FOPD and ST-ABC instead of nodular fasciitis for involving lower limbs most frequently and showing recurrent COL1A1::USP6 fusion. Additionally, this study also found two novel USP6 fusion partners, which further expanded our knowledge of this neoplastic spectrum

Quick Identification of ABC Trilayer Graphene at Nanoscale Resolution via a Near-field Optical Route

ABC-stacked trilayer graphene has exhibited a variety of correlated phenomena owing to its relatively flat bands and gate-tunable bandgap. However, convenient methods are still lacking for identifying ABC graphene with nanometer-scale resolution. Here we demonstrate that the scanning near-field optical microscope (SNOM) working in ambient conditions can provide quick recognition of ABC trilayer graphene with no ambiguity and excellent resolution (~20 nm). The recognition is based on the difference in their near-field infrared (IR) responses between the ABA and ABC trilayers. We show that in most frequencies, the response of the ABC trilayer is weaker than the ABA trilayer. However, near the graphene phonon frequency (~1585 cm-1), ABC's response increases dramatically when gated and exhibits a narrow and sharp Fano-shape resonant line, whereas the ABA trilayer is largely featherless. Consequently, the IR contrast between ABC and ABA becomes reversed and can even be striking (ABC/ABA~3) near the graphene phonon frequency. The observed near-field IR features can serve as a golden rule to quickly distinguish ABA and ABC trilayers with no ambiguity, which could largely advance the exploration of correlation physics in ABC-stacked trilayer graphene

Influence of academic stress and school bullying on self-harm behaviors among Chinese middle school students: The mediation effect of depression and anxiety

ObjectiveThe purpose of this study was to explore the relationship between academic stress, school bullying and self-harm behaviors among Chinese middle school students and to further explore the impact of anxiety and depression on this relationship.MethodsThe students (aged 12–16 years) in a middle school in Changsha city were invited to respond to a questionnaire through an online platform. The Patient Health Questionnaire-9 (PHQ-9) and Generalized Anxiety Disorder-7 (GAD-7) were used to assess the severity of anxiety and depressive symptoms, respectively. The experience of being bullied, academic stress, and self-harm behaviors were assessed using several questions on the basis of previous studies.ResultsA total of 1,313 middle school students completed the study, and 3.40% and 4.10% of them reported suicide attempts (SAs) and non-suicidal self-injury (NSSI), respectively. Univariate logistic regression analysis revealed that anxiety symptoms (OR = 1.23, 95% CI: 1.18–1.28; OR = 1.25, 95% CI: 1.19–1.31), depressive symptoms (OR = 1.20, 95% CI: 1.16–1.25; OR = 1.26, 95% CI: 1.20–1.31), school bullying (OR = 3.8, 95% CI: 2.11–6.89; OR = 2.76, 95% CI: 1.39–5.47), and academic stress (OR = 2.20, 95% CI: 1.27–3.80; OR = 3.80, 95% CI: 1.20–7.25) were common factors of NSSI and SAs. In addition, depressive symptoms showed a mediating effect on the association of school bullying and academic stress with SAs or NSSI, and anxiety symptoms showed a mediating effect on the association of school bullying and academic stress with NSSI only.ConclusionAppropriate strategies are needed to reduce academic pressure and prevent school bullying. Meanwhile, negative emotions such as depression and anxiety should be evaluated and intervened in to prevent self-harm behaviors among middle school students