Parameter estimation and arrangement optimization of particle dampers on the cantilever rectangular plate

The particle damper as a passive means for vibration suppression, is preferred due to its simplicity and easy to implement and control, with no need for any auxiliary power equipment. The bottleneck of the design for the particle damper is that damping performance is influenced by many parameters including particle material and size, packing ratio and cavity dimensions of enclosure such as length, width and diameter. In fact, the overall damping effect of particle damper is closely related to the primary structure system parameters. However, the influences of the excitation point, dampers arrangements, excitation force amplitude, and excitation force type for overall damping effect are scarce reported in the open literatures. How to exert particle damper on the structure and how many particles filled within the cavity, which are needed to face the problem in the engineering practice. In the face of doubt above-mentioned, the above questions will be clarified in this paper. At the same time, an optimization algorithm by the application of genetic algorithms of BP neural network is carried out in order to get most excellent damping effect. These will offer significance guidance to design and conduct particle dampers implement in the specific engineering practice with reference significance

The Specificity of Human Capital and Risk Management of the College Counselor from the Perspective of Internationalization

Shifting the concept of human resource to the concept of human capital is an inevitable tendency in developing human resource of college counselor. It is because the college counselor has its own specificity that it is hardly possible to avoid the risks of entry and exit which brings in completely. The paper listed the priority of psychological capital, human capital and social capital of the college counselor from the perspective of in-system in the order to attempt to discuss their inner logical relationship based on the basic theory of risk management. Key words: College counsellor; The specificity of human capital; Risk management; In-system Résumé: Déplacer le concept de ressources humaines pour le concept de capital humain est une tendance inévitable dans le développement des ressources humaines de conseiller du collège. C'est parce que le conseiller collège a sa propre spécificité qu'il n'est guère possible d'éviter les risques d'entrée et de sortie qui amène à fond. Le document énumère les priorités du capital psychologique, le capital humain et le capital social de la conseillère collège dans la perspective d'en-système dans l'ordre pour tenter de discuter de leur relation logique interne basé sur la théorie de base de gestion des risques. Mots clés: Université de conseiller; La spécificité du capital humain; La gestion des risques; Et du systèm

Synonym Detection Using Syntactic Dependency And Neural Embeddings

Recent advances on the Vector Space Model have significantly improved some NLP applications such as neural machine translation and natural language generation. Although word co-occurrences in context have been widely used in counting-/predicting-based distributional models, the role of syntactic dependencies in deriving distributional semantics has not yet been thoroughly investigated. By comparing various Vector Space Models in detecting synonyms in TOEFL, we systematically study the salience of syntactic dependencies in accounting for distributional similarity. We separate syntactic dependencies into different groups according to their various grammatical roles and then use context-counting to construct their corresponding raw and SVD-compressed matrices. Moreover, using the same training hyperparameters and corpora, we study typical neural embeddings in the evaluation. We further study the effectiveness of injecting human-compiled semantic knowledge into neural embeddings on computing distributional similarity. Our results show that the syntactically conditioned contexts can interpret lexical semantics better than the unconditioned ones, whereas retrofitting neural embeddings with semantic knowledge can significantly improve synonym detection

An Novel Six-Segment Modulation Strategy for Three-Phase Isolated PFC Converter

A three-phase isolated rectifier features bidirectional power conversion and galvanic isolation, and is attractive as a high-efficiency energy conversion system. However, when a conventional modulation is applied to this rectifier, the excessive DC-link current ripple will result in increasing switching losses or the size of DC-link inductance, which is not cost-effective. In order to effectively reduce the current ripple, this paper proposes a “six segment” PWM (Pulse Width Modulation) strategy. It can significantly reduce the current ripple compared with the existing “eight segment” PWM strategy. Meanwhile, the current quality of the grid is improved. Finally, the experimental tests were carried out. The experimental results reveal that, compared to the traditional “eight segment” PWM, the dc-side current ripple significantly reduced from 2 A to 0.8 A, the total harmonic distortion significantly reduced from 5.69% to 2.41%, and the power factor increased from 0.87 to 0.99, verifying the effectiveness of the proposed method

A Novel Circulating Current Suppression for Paralleled Current Source Converter Based on Virtual Impedance Concept

The circulating current is one of the important issues for parallel converters. It affects the system stable operation and degrades the power quality. In order to reduce the circulating current of the parallel converter and reduce the harmonic pollution to the power grid, a new circulating current suppression strategy is proposed for the parallel current source converter without any communication line. This strategy is able to realize the current sharing between parallel modules by changing the external characteristics of the parallel modules to thus suppress the circulating current among the parallel current source converters. The proposed control strategy adopts DC-side droop control and AC-side virtual impedance control. The DC-side droop control is used to generate the reference voltage of each parallel module, while the AC-side virtual impedance is used to the circulating current suppression. We performed a time domain test of the parallel converter, and the results show that the proposed control strategy reduced the RMS circulating current of the parallel converter by 50% and effectively reduced the grid-side current THD while ensuring the stable operation of the converter. The effectiveness of the proposed control strategy was, therefore, verified

Study of Histopathological and Molecular Changes of Rat Kidney under Simulated Weightlessness and Resistance Training Protective Effect

To explore the effects of long-term weightlessness on the renal tissue, we used the two months tail suspension model to simulate microgravity and investigated the simulated microgravity on the renal morphological damages and related molecular mechanisms. The microscopic examination of tissue structure and ultrastructure was carried out for histopathological changes of renal tissue morphology. The immunohistochemistry, real-time PCR and Western blot were performed to explore the molecular mechanisms associated the observations. Hematoxylin and eosin (HE) staining showed severe pathological kidney lesions including glomerular atrophy, degeneration and necrosis of renal tubular epithelial cells in two months tail-suspended rats. Ultrastructural studies of the renal tubular epithelial cells demonstrated that basal laminas of renal tubules were rough and incrassate with mitochondria swelling and vacuolation. Cell apoptosis in kidney monitored by the expression of Bax/Bcl-2 and caspase-3 accompanied these pathological damages caused by long-term microgravity. Analysis of the HSP70 protein expression illustrated that overexpression of HSP70 might play a crucial role in inducing those pathological damages. Glucose regulated protein 78 (GRP78), one of the endoplasmic reticulum (ER) chaperones, was up-regulated significantly in the kidney of tail suspension rat, which implied that ER-stress was associated with apoptosis. Furthermore, CHOP and caspase-12 pathways were activated in ER-stress induced apoptosis. Resistance training not only reduced kidney cell apoptosis and expression of HSP70 protein, it also can attenuate the kidney impairment imposed by weightlessness. The appropriate optimization might be needed for the long term application for space exploration

Zoonotic Cryptosporidium Parasites Possess a Unique Carbohydrate-binding Protein (Malectin) that is Absent in other Apicomplexan Lineages

Malectin is a carbohydrate-binding protein that binds Glc(2)- N -glycan and is present in animals and some alveolates. This study aimed to characterize the general molecular and biochemical features of Cryptosporidium parvum malectin (CpMal). Polyclonal antibodies were raised for detecting native CpMal by western blotting and immunofluorescence assays. Recombinant CpMal and human malectin (HsMal) were produced, and their binding activities to amylose and the host cell surface were compared. Far-western blotting and far-immunofluorescence assays were used to detect potential binding partners of CpMal in the parasite. Native CpMal appeared to exist in dimeric form in the parasite and was distributed in a diffuse pattern over sporozoites but was highly concentrated on the anterior and posterior sides near the nuclei. CpMal, compared with HsMal, had significantly lower affinity for binding amylose but substantially higher activity for binding host cells. Recombinant CpMal recognized three high molecular weight protein bands and labeled the sporozoite posterior end corresponding to the crystalloid body, thus suggesting the presence of its potential ligands in the parasite. Two proteins identified by proteomics should be prioritized for future validation of CpMal-binding. CpMal notably differs from HsMal in molecular and biochemical properties; thus, further investigation of its biochemical and biological roles is warranted

Mechanism for Selective Binding of Aromatic Compounds on Oxygen-Rich Graphene Nanosheets Based on Molecule Size/Polarity Matching

Selective binding of organic compounds is the cornerstone of many important industrial and pharmaceutical applications. Here, we achieved highly selective binding of aromatic compounds in aqueous solution and gas phase by oxygen-enriched graphene oxide (GO) nanosheets via a previously unknown mechanism based on size matching and polarity matching. Oxygen-containing functional groups (predominately epoxies and hydroxyls) on the nongraphitized aliphatic carbons of the basal plane of GO formed highly polar regions that encompass graphitic regions slightly larger than the benzene ring. This facilitated size match–based interactions between small apolar compounds and the isolated aromatic region of GO, resulting in high binding selectivity relative to larger apolar compounds. The interactions between the functional group(s) of polar aromatics and the epoxy/hydroxyl groups around the isolated aromatic region of GO enhanced binding selectivity relative to similar-sized apolar aromatics. These findings provide opportunities for precision separations and molecular recognition enabled by size/polarity match–based selectivity

Spontaneous Brain Activity in the Default Mode Network Is Sensitive to Different Resting-State Conditions with Limited Cognitive Load

BACKGROUND: Recent functional MRI (fMRI) studies have demonstrated that there is an intrinsically organized default mode network (DMN) in the resting brain, primarily made up of the posterior cingulate cortex (PCC) and the medial prefrontal cortex (MPFC). Several previous studies have found that the DMN is minimally disturbed during different resting-state conditions with limited cognitive demand. However, this conclusion was drawn from the visual inspection of the functional connectivity patterns within the DMN and no statistical comparison was performed. METHODOLOGY/PRINCIPAL FINDINGS: Four resting-state fMRI sessions were acquired: 1) eyes-closed (EC) (used to generate the DMN mask); 2) EC; 3) eyes-open with no fixation (EO); and 4) eyes-open with a fixation (EO-F). The 2-4 sessions were counterbalanced across participants (n = 20, 10 males). We examined the statistical differences in both functional connectivity and regional amplitude of low frequency fluctuation (ALFF) within the DMN among the 2-4 resting-state conditions (i.e., EC, EO, and EO-F). Although the connectivity patterns of the DMN were visually similar across these three different conditions, we observed significantly higher functional connectivity and ALFF in both the EO and the EO-F conditions as compared to the EC condition. In addition, the first and second resting EC conditions showed significant differences within the DMN, suggesting an order effect on the DMN activity. CONCLUSIONS/SIGNIFICANCE: Our findings of the higher DMN connectivity and regional spontaneous activities in the resting state with the eyes open suggest that the participants might have more non-specific or non-goal-directed visual information gathering and evaluation, and mind wandering or daydreaming during the resting state with the eyes open as compared to that with the eyes closed, thus providing insights into the understanding of unconstrained mental activity within the DMN. Our results also suggest that it should be cautious when choosing the type of a resting condition and designating the order of the resting condition in multiple scanning sessions in experimental design

An open science resource for establishing reliability and reproducibility in functional connectomics

Efforts to identify meaningful functional imaging-based biomarkers are limited by the ability to reliably characterize inter-individual differences in human brain function. Although a growing number of connectomics-based measures are reported to have moderate to high test-retest reliability, the variability in data acquisition, experimental designs, and analytic methods precludes the ability to generalize results. The Consortium for Reliability and Reproducibility (CoRR) is working to address this challenge and establish test-retest reliability as a minimum standard for methods development in functional connectomics. Specifically, CoRR has aggregated 1,629 typical individuals’ resting state fMRI (rfMRI) data (5,093 rfMRI scans) from 18 international sites, and is openly sharing them via the International Data-sharing Neuroimaging Initiative (INDI). To allow researchers to generate various estimates of reliability and reproducibility, a variety of data acquisition procedures and experimental designs are included. Similarly, to enable users to assess the impact of commonly encountered artifacts (for example, motion) on characterizations of inter-individual variation, datasets of varying quality are included