A Discrete and Hybrid Approach to Predicting Diametrical Errors in Slender Shaft Turning

Slender shafts have a high length-to-radius ratio, low rigidity, and are often machined on a lathe to comply with the tight tolerance requirement. The machined accuracy for slender shafts, which is reflected in its diametrical deviations, is very sensitive to forces exerted by the cutting tool. To compensate for such errors effectively, this research aims to predict the diametrical deviations in slender shafts turning process efficiently and accurately. First, based on the geometric principles in turning processes, a mathematical model is built, in order to relate the given depth of cut and the shaft deflection due to the force of the cutting tool to the diametrical deviations. Then a novel finite element model considering the practical machining situation is developed to solve the aforementioned mathematical model. Compared with traditional finite element methods, the novel method addresses the interaction between the depth of cut and the cutting force throughout the machining process. A discretization method is employed to handle this coupled interaction. The approach to diametrical deviations prediction is verified with the experimental data and situations for various machining parameters and stock materials are discussed. The approach is also extended to the generic case involving workpieces with different diameters features along the shaft

Neural differences between the processing of musical meaning conveyed by direction of pitch change and natural music in congenital amusia

Music is a unique communication system for human beings. Iconic musical meaning is one dimension of musical meaning, which emerges from musical information resembling sounds of objects, qualities of objects, or qualities of abstract concepts. The present study investigated whether congenital amusia, a disorder of musical pitch perception, impacts processing of iconic musical meaning. With a cross-modal semantic priming paradigm, target images were primed by semantically congruent or incongruent musical excerpts, which were characterized by direction (upward or downward) of pitch change (Experiment 1), or were selected from natural music (Experiment 2). Twelve Mandarin-speaking amusics and 12 controls performed a recognition (implicit) and a semantic congruency judgment (explicit) task while their EEG waveforms were recorded. Unlike controls, amusics failed to elicit an N400 effect when musical meaning was represented by direction of pitch change, regardless of the nature of the tasks (implicit versus explicit). However, the N400 effect in response to musical meaning in natural musical excerpts was observed for both groups in both types of tasks. These results indicate that amusics are able to process iconic musical meaning through multiple acoustic cues in natural musical excerpts, but not through direction of pitch change. This is the first study to investigate the processing of musical meaning in congenital amusia, providing evidence in support of the “melodic contour deafness hypothesis” with regard to iconic musical meaning processing in this disorder

Research Directions and Projects In an Institute of Developmental Psychology in China

We are a team who maintained to focus on 3 fields in people’s mental health recent years: marriage and family research and therapy, mental health of middle and primary school students, and internet addiction in youth. In every field, we focus on both fundamental research and clinical practice. We aim to explore mechanisms using survey, observation and cognitive neuroscience methods (fMRI), and develop prediction and intervention projects based on research, to improve people’s life and policies

Superelastic SMA Belleville washers for seismic resisting applications: experimental study and modelling strategy

This study sheds considerable light on the potential of superelastic shape memory alloy Belleville washers for innovative seismic resisting applications. A series of experimental studies were conducted on washers with different stack combinations under varying temperatures and loading scenarios. The washers showed satisfactory self-centring and energy dissipation capacities at room temperature, although slight degradations of the hysteretic responses accompanied by residual deformations were induced. The hysteretic loops became stable after a few number of cycles, indicating good repeatability. The washers also showed good flexibility in terms of load resistance and deformation, which could be easily varied via changes in the stack combination. Compromised self-centring responses were observed at temperatures below 0 °C or above 40 °C, and a numerical study, validated by the experimental results, was adopted to further investigate the deformation mechanism of the washers. A further phenomenological model, taking account of the degradation effects under varied temperatures, was developed to enable effective and accurate simulation of devices incorporating the washers. Good agreements were observed between the test and simulation results, and the model was shown to have good numerical robustness for wide engineering applications

Local Geometric Distortions Resilient Watermarking Scheme Based on Symmetry

As an efficient watermark attack method, geometric distortions destroy the synchronization between watermark encoder and decoder. And the local geometric distortion is a famous challenge in the watermark field. Although a lot of geometric distortions resilient watermarking schemes have been proposed, few of them perform well against local geometric distortion like random bending attack (RBA). To address this problem, this paper proposes a novel watermark synchronization process and the corresponding watermarking scheme. In our scheme, the watermark bits are represented by random patterns. The message is encoded to get a watermark unit, and the watermark unit is flipped to generate a symmetrical watermark. Then the symmetrical watermark is embedded into the spatial domain of the host image in an additive way. In watermark extraction, we first get the theoretically mean-square error minimized estimation of the watermark. Then the auto-convolution function is applied to this estimation to detect the symmetry and get a watermark units map. According to this map, the watermark can be accurately synchronized, and then the extraction can be done. Experimental results demonstrate the excellent robustness of the proposed watermarking scheme to local geometric distortions, global geometric distortions, common image processing operations, and some kinds of combined attacks

Associations between Leisure Activities and HIV Risk Behaviors among Rural Migrants in Urban China

Although much has been documented on factors affecting HIV risk behavior among rural-to-urban migrants in China, data are lacking on the impact of leisure activities. In this study, we examined the association between leisure activities and HIV risk behavior among a sample of rural-to-urban migrants from two large cities (Beijing and Nanjing) in China. Cross-sectional data were analyzed for a sample of 4,085 participants aged 18 to 30 years (40.5% females). Findings from the analysis indicated that although the migrants worked long hours, they engaged in a number of activities when they did not work, including watching television (60.2%), reading (59.1%), sleeping (55.6%), and chatting with friends and co-workers (45.0%). Multiple regression analysis indicated that reading, doing chores (females only), listening to radio programs/audio CDs (male only) were associated with reduced likelihood of HIV risk behavior while playing cards in groups, visiting entertaining installments, watching videos (including Xrated, males only), and wondering around (females only) were associated with increased likelihood of HIV risk behavior. Findings of this study suggest that constructive and individualized activities (e.g., reading, listening to radios, and doing chores) may prevent migrants from engage in HIV risk behaviors while group and entertaining activities related to drugs and sex may increase the odds for migrants to engage in HIV risk behaviors. Prevention research should consider leisure activities as both an influential factor (including time trends and gender differences) for program development and an important venue for program delivery

Discrimination, Perceived Social Inequity, and Mental Health Among Rural-to-Urban Migrants in China

Status-based discrimination and inequity have been associated with the process of migration, especially with economics-driven internal migration. However, their association with mental health among economy-driven internal migrants in developing countries is rarely assessed. This study examines discriminatory experiences and perceived social inequity in relation to mental health status among rural-to-urban migrants in China. Cross-sectional data were collected from 1,006 rural-to-urban migrants in 2004-2005 in Beijing, China. Participants reported their perceptions and experiences of being discriminated in daily life in urban destination and perceived social inequity. Mental health was measured using the symptom checklist-90 (SCL-90). Multivariate analyses using general linear model were performed to test the effect of discriminatory experience and perceived social inequity on mental health. Experience of discrimination was positively associated with male gender, being married at least once, poorer health status, shorter duration of migration, and middle range of personal income. Likewise, perceived social inequity was associated with poorer health status, higher education attainment, and lower personal income. Multivariate analyses indicate that both experience of discrimination and perceived social inequity were strongly associated with mental health problems of rural-to-urban migrants. Experience of discrimination in daily life and perceived social inequity have a significant influence on mental health among rural-to-urban migrants. The findings underscore the needs to reduce public or societal discrimination against rural-to-urban migrants, to eliminate structural barriers (i.e., dual household registrations) for migrants to fully benefit from the urban economic development, and to create a positive atmosphere to improve migrant\u27s psychological well-being

Thermal analysis of FeCoCu pre-alloyed powders used for diamond tools

By simulating the pressureless sintering process, the thermal effects of FeCoCu pre-alloyed powders have been investigated. According to the notions of the Kissinger method, the activation energies in the expansion-shrinkage conversion stage are analyzed. Results show that with Fe content increasing, the specimens’ specific heat capacity values present the increasing trend. The 25 %Fe–15 %Co–60 %Cu specimens have negative enthalpy value at 10 and 20°C/min heating rate but positive values at 30 °С/min. For the specimens with lower Cu content, the enthalpies are always positive. It is established that both the specific heat capacity and enthalpy are larger when at higher heating rates. The activation energy of the 65 %Fe–15 %Co–20 %Cu specimens is 10 times higher than that of the 25 %Fe–15 %Co–60 %Cu specimens and the 45 %Fe–15 %Co–40 %Cu specimens.При моделюванні процесу спікання без тиску досліджено термічні ефекти в попередньо легованих порошках FeCoCu. З використанням методу Кіссінджера проаналізовано енергію активації на стадії розширення–усадка. Результати показують, що при збільшенні вмісту Fe значення питомої теплоємності демонструють тенденцію до зростання. Зразки 25 %Fe–15 %Co–60 %Cu мають негативні значення ентальпії при швидкості нагріву 10 ° і 20 °С/хв, але позитивні при 30 °С/хв. Для зразків з меншим вмістом Cu ентальпія завжди позитивна. Встановлено, що питома теплоємність і ентальпія більші при більш високіх швидкостях нагрівання. Енергія активації зразків 65 %Fe–15 %Co–20 %Cu у 10 разів вища, ніж зразків 25 %Fe–15 %Co–60 %Cu і 45 %Fe–15 %Co–40 %Cu.При моделировании процесса спекания без приложения давления исследованы термические эффекты в предварительно легированных порошках FeCoCu. С использованием метода Киссинджера проанализирована энергия активации на стадии расширение–усадка. Результаты показывают, что с увеличением содержания железа значения удельной теплоемкости образцов демонстрируют тенденцию к повышению. Образцы 25 %Fe–15 %Co–60 %Cu имеют отрицательные значения энтальпии при скорости нагрева 10 и 20 °С/мин, но положительные при 30 °С/мин. Для образцов с меньшим содержанием Cu энтальпия всегда положительна. Установлено, что удельная теплоемкость и энтальпия больше при более высоких скоростях нагрева. Энергия активации образцов 65 %Fe–15 %Co–20 %Cu в 10 раз выше, чем образцов 25 %Fe–15 %Co–60 %Cu и 45 %Fe–15 %Co–40 %Cu

Bootstrapped Masked Autoencoders for Vision BERT Pretraining

We propose bootstrapped masked autoencoders (BootMAE), a new approach for vision BERT pretraining. BootMAE improves the original masked autoencoders (MAE) with two core designs: 1) momentum encoder that provides online feature as extra BERT prediction targets; 2) target-aware decoder that tries to reduce the pressure on the encoder to memorize target-specific information in BERT pretraining. The first design is motivated by the observation that using a pretrained MAE to extract the features as the BERT prediction target for masked tokens can achieve better pretraining performance. Therefore, we add a momentum encoder in parallel with the original MAE encoder, which bootstraps the pretraining performance by using its own representation as the BERT prediction target. In the second design, we introduce target-specific information (e.g., pixel values of unmasked patches) from the encoder directly to the decoder to reduce the pressure on the encoder of memorizing the target-specific information. Thus, the encoder focuses on semantic modeling, which is the goal of BERT pretraining, and does not need to waste its capacity in memorizing the information of unmasked tokens related to the prediction target. Through extensive experiments, our BootMAE achieves $84.2\%$ Top-1 accuracy on ImageNet-1K with ViT-B backbone, outperforming MAE by $+0.8\%$ under the same pre-training epochs. BootMAE also gets $+1.0$ mIoU improvements on semantic segmentation on ADE20K and $+1.3$ box AP, $+1.4$ mask AP improvement on object detection and segmentation on COCO dataset. Code is released at https://github.com/LightDXY/BootMAE.Comment: ECCV 2022, code is available at https://github.com/LightDXY/BootMA

Expression mapping of GREM1 and functional contribution of its-secreting-cells in the brain using transgenic mouse models

Gremlin 1 (Grem1) is a secreted protein that antagonizes bone morphogenetic proteins (BMPs). While abnormal Grem1 expression has been reported to cause behavioral defects in postpartum mice, the spatial and cellular distribution of GREM1 in the brain and the influence of the Grem1-secreating cells on brain function and behavior remain unclear. To address this, we designed a genetic cassette incorporating a 3 × Flag-TeV-HA-T2A-tdTomato sequence, resulting in the creation of a novel Grem1Tag mouse model, expressing an epitope tag (3 × Flag-TeV-HA-T2A) followed by a fluorescent reporter (tdTomato) under the control of the endogenous Grem1 promoter. This design facilitated precise tracking of the cell origin and distribution of GREM1 in the brain using tdTomato and Flag (or HA) markers, respectively. We confirmed that the Grem1Tag mouse exhibited normal motor, cognitive, and social behaviors at postnatal 60 days (P60), compared with C57BL/6 J controls. Through immunofluorescence staining, we comprehensively mapped the distribution of Grem1-secreting cells across the central nervous system. Pervasive Grem1 expression was observed in the cerebral cortex (Cx), medulla, pons, and cerebellum, with the highest levels in the Cx region. Notably, within the Cx, GREM1 was predominantly secreted by excitatory neurons, particularly those expressing calcium/calmodulin-dependent protein kinase II alpha (Camk2a), while inhibitory neurons (parvalbumin-positive, PV+) and glial cells (oligodendrocytes, astrocytes, and microglia) showed little or no Grem1 expression. To delineate the functional significance of Grem1-secreting cells, a selective ablation at P42 using a diphtheria toxin A (DTA) system resulted in increased anxiety-like behavior and impaired memory in mice. Altogether, our study harnessing the Grem1Tag mouse model reveals the spatial and cellular localization of GREM1 in the mouse brain, shedding light on the involvement of Grem1-secreting cell in modulating brain function and behavior. Our Grem1Tag mouse serves as a valuable tool for further exploring the precise role of Grem1 in brain development and disease