Dynamic simulation analysis of spur gear space driven system with large inertia load

The wide application of large inertia loads in space drive mechanisms is relatively rare in theoretical research. An 8-degree-of-freedom nonlinear dynamic model is established for the time-varying and nonlinear perturbation problems of a large inertia load space drive mechanism. The model is a two-stage spur gear model in which the effects of backlash and time-varying stiffness are considered. The 3D model was imported into ADAMS, and the nonlinear dynamic response of the system was studied by motion simulation. This paper sets up a large inertia experimental device to collect and process data. Comparing experimental results with Adams results, the correctness of the numerical model was verified, and the reasons for the differences between the two were explained. A comparative analysis of the load response under different inertia was performed to illustrate the importance of studying large inertia loads. The simulation results show that the output shaft has a great influence on the dynamic response. Changing the material of the gear can improve the transmission precision of the gear system. The analysis results in this paper enrich the research on the dynamic response of gear system, and provide a theoretical basis for the subsequent design of large inertia load gear system and improve vibration and noise during operation

Identification of Changes in Wheat (Triticum aestivum L.) Seeds Proteome in Response to Anti–trx s Gene

BACKGROUND: Thioredoxin h (trx h) is closely related to germination of cereal seeds. The cDNA sequences of the thioredoxin s (trx s) gene from Phalaris coerulescens and the thioredoxin h (trx h) gene from wheat are highly homologous, and their expression products have similar biological functions. Transgenic wheat had been formed after the antisense trx s was transferred into wheat, and it had been certified that the expression of trx h decreased in transgenic wheat, and transgenic wheat has high resistance to pre-harvest sprouting. METHODOLOGY/PRINCIPAL FINDINGS: Through analyzing the differential proteome of wheat seeds between transgenic wheat and wild type wheat, the mechanism of transgenic wheat seeds having high resistance to pre-harvest sprouting was studied in the present work. There were 36 differential proteins which had been identified by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF-MS). All these differential proteins are involved in regulation of carbohydrates, esters, nucleic acid, proteins and energy metabolism, and biological stress. The quantitative real time PCR results of some differential proteins, such as trx h, heat shock protein 70, α-amylase, β-amylase, glucose-6-phosphate isomerase, 14-3-3 protein, S3-RNase, glyceraldehyde-3-phosphate dehydrogenase, and WRKY transcription factor 6, represented good correlation between transcripts and proteins. The biological functions of many differential proteins are consistent with the proposed role of trx h in wheat seeds. CONCLUSIONS/SIGNIFICANCE: A possible model for the role of trx h in wheat seeds germination was proposed in this paper. These results will not only play an important role in clarifying the mechanism that transgenic wheat has high resistance to pre-harvest sprouting, but also provide further evidence for the role of trx h in germination of wheat seeds

PromptVC: Flexible Stylistic Voice Conversion in Latent Space Driven by Natural Language Prompts

Style voice conversion aims to transform the style of source speech to a desired style according to real-world application demands. However, the current style voice conversion approach relies on pre-defined labels or reference speech to control the conversion process, which leads to limitations in style diversity or falls short in terms of the intuitive and interpretability of style representation. In this study, we propose PromptVC, a novel style voice conversion approach that employs a latent diffusion model to generate a style vector driven by natural language prompts. Specifically, the style vector is extracted by a style encoder during training, and then the latent diffusion model is trained independently to sample the style vector from noise, with this process being conditioned on natural language prompts. To improve style expressiveness, we leverage HuBERT to extract discrete tokens and replace them with the K-Means center embedding to serve as the linguistic content, which minimizes residual style information. Additionally, we deduplicate the same discrete token and employ a differentiable duration predictor to re-predict the duration of each token, which can adapt the duration of the same linguistic content to different styles. The subjective and objective evaluation results demonstrate the effectiveness of our proposed system.Comment: Submitted to ICASSP 202

An outbreak of aseptic meningitis caused by a distinct lineage of coxsackievirus B5 in China

SummaryIn 2009, an outbreak of aseptic meningitis caused by coxsackievirus B5 (CVB5) occurred in China. Epidemiological investigations of this outbreak revealed that the proportion of severe cases (14/43, 33%) was higher than in other outbreaks associated with CVB5 in China. Phylogenetic analysis of the entire VP1 sequences demonstrated that the CVB5 isolates from the severe cases form a distinct lineage belonging to genogroup E with the Shandong isolates of 2009. A substitution of serine (S) to asparagine (N) at amino acid 95 in the VP1 region may be a major virulence determinant for the virus. Our findings suggest that this new lineage of CVB5 is circulating in China. Further genetic studies are needed in order to gain a better insight into the genetic variability of CVB5 isolates and the relationship with pathogenicity

Bipolar Membrane Electrodialysis for Ammonia Recovery from Synthetic Urine: Experiments, Modeling, and Performance Analysis

Recovering nitrogen from source-separated urine is an important part of the sustainable nitrogen management. A novel bipolar membrane electrodialysis with membrane contactor (BMED–MC) process is demonstrated here for efficient recovery of ammonia from synthetic source-separated urine (∼3772 mg N L–1). In a BMED–MC process, electrically driven water dissociation in a bipolar membrane simultaneously increases the pH of the urine stream and produces an acid stream for ammonia stripping. With the increased pH of urine, ammonia transports across the gas-permeable membrane in the membrane contactor and is recovered by the acid stream as ammonium sulfate that can be directly used as fertilizer. Our results obtained using batch experiments demonstrate that the BMED–MC process can achieve 90% recovery. The average ammonia flux and the specific energy consumption can be regulated by varying the current density. At a current density of 20 mA cm–2, the energy required to achieve a 67.5% ammonia recovery in a 7 h batch mode is 92.8 MJ kg–1 N for a bench-scale system with one membrane stack and can approach 25.8 MJ kg–1 N for large-scale systems with multiple membrane stacks, with an average ammonia flux of 2.2 mol m–2 h–1. Modeling results show that a continuous BMED–MC process can achieve a 90% ammonia recovery with a lower energy consumption (i.e., 12.5 MJ kg–1 N). BMED–MC shows significant potential for ammonia recovery from source-separated urine as it is relatively energy-efficient and requires no external acid solution

Rapid phenotypic evolution in multidrug-resistant Klebsiella pneumoniae hospital outbreak strains

L. v. D., L. P. S., X. D., H. W. and F. B. acknowledge financial support from the Newton Trust UK–China NSFC initiative (grants MR/P007597/1 and 81661138006). F. B. acknowledges support from the BBSRC GCRF scheme. H. W. additionally acknowledges support from China NSFC grant 81625014. H. C. acknowledges financial support from a 111 Talent Discipline Planning of PKUPH award for a 1-year visit at University College London. Data statement: All supporting data, code and protocols have been provided within the article or through supplementary data files. Nine supplementary tables and fifteen supplementary figures are available with the online version of this article.Peer reviewedPublisher PD

Metacommunity ecology meets bioassessment : Assessing spatio-temporal variation in multiple facets of macroinvertebrate diversity in human-influenced large lakes

Highlights • We examined drivers of 6 biotic metrics in a metacommunity context in two large lakes. • The relative roles of spatial, human-induced and natural factors were quantified. • The roles of spatial variables are comparable with local environmental conditions. • The relative roles of different drivers varied substantially among seasons. • Spatial processes, natural conditions and temporal variation should be considered.Metacommunity theory emphasizes that local communities are jointly affected by environmental filtering and spatial processes. However, the roles of spatial processes are often given insufficient attention in bioassessment practices, which may bias the assessments of ecological status based on biotic metrics. Here, we quantified the relative importance and the seasonal stability of spatial processes, natural conditions and human-induced factors in structuring variation in different bioassessment metrics based on macroinvertebrate communities. Our study systems were two extensively sampled large and shallow lakes with strong nutrient gradients related to human disturbance. The roles of different drivers were examined for three kinds of indicators: general diversity, trait-based and taxonomic distinctness metrics, and their performance in characterizing human disturbance was evaluated. Overall, human-induced and spatial factors were all important in explaining variation in the three types of bioassessment metrics. Contrary to our expectations, however, we found that the importance of spatial processes on bioassessment metrics can be comparable to the effects of local environmental conditions at the within-lake scale. Furthermore, the results showed substantial seasonal variability in the relative roles of different drivers, which might be linked to life-cycle seasonality of macroinvertebrates. As expected, trait-based metrics generally were best associated with human-induced variables in both lakes, whereas general diversity and taxonomic distinctness metrics performed poorly. The low effectiveness of taxonomic distinctness metrics might due to low species richness associated with high nutrient levels. To conclude, our results suggest that bioassessment cannot exclusively rely on the idea of environmental filtering even if we focus on fine spatial scales. We hence strongly urge that spatial processes, natural drivers and temporal variability should be better considered in combination in the development and application of bioassessment approaches. In addition, taxonomic distinctness measures should be used with caution, especially for the ecosystems and organism groups typically characterized by low species richness

Acid-Base Clusters during Atmospheric New Particle Formation in Urban Beijing

Molecular clustering is the initial step of atmospheric new particle formation (NPF) that generates numerous secondary particles. Using two online mass spectrometers with and without a chemical ionization inlet, we characterized the neutral clusters and the naturally charged ion clusters during NPF periods in urban Beijing. In ion clusters, we observed pure sulfuric acid (SA) clusters, SA-amine clusters, SA-ammonia (NH3) clusters, and SA-amine-NH3 clusters. However, only SA clusters and SA-amine clusters were observed in the neutral form. Meanwhile, oxygenated organic molecule (OOM) clusters charged by a nitrate ion and a bisulfate ion were observed in ion clusters. Acid-base clusters correlate well with the occurrence of sub-3 nm particles, whereas OOM clusters do not. Moreover, with the increasing cluster size, amine fractions in ion acid-base clusters decrease, while NH3 fractions increase. This variation results from the reduced stability differences between SA-amine clusters and SA-NH3 clusters, which is supported by both quantum chemistry calculations and chamber experiments. The lower average number of dimethylamine (DMA) molecules in atmospheric ion clusters than the saturated value from controlled SA-DMA nucleation experiments suggests that there is insufficient DMA in urban Beijing to fully stabilize large SA clusters, and therefore, other basic molecules such as NH3 play an important role.Peer reviewe