A Study of Static and Dynamic Mechanical Behavior of the Substrate in Ultrasonic Consolidation

A new 2-D FEM model is developed for a fundamental study of the time dependent mechanical behavior of the substrate in ultrasonic consolidation. The simulation shows that for a given vibration condition, the amplitude of contact friction stress and displacement stabilize to a saturated state after certain number of ultrasonic cycles. With the increased substrate height, the amplitude of contact frictional stress decreases, while that of contact interface displacement increases. The energy density and transfer coefficient at the contact interface with different substrate heights can be used as parameters to predict the potential for ultrasonic bonding. The reason for the decrease in the frictional stress and displacement at the contact interface for certain substrate height seems to be caused by the complicated wave interference occurring in the substrate. A specific substrate geometry generates a minimum strain state at the interface as a result of wave superposition. Such minimum strain state is believed to have produced the “lack of bonding” defect.Mechanical Engineerin

Usage History of Scientific Literature: Nature Metrics and Metrics of Nature Publications

In this study, we analyze the dynamic usage history of Nature publications over time using Nature metrics data. We conduct analysis from two perspectives. On the one hand, we examine how long it takes before the articles' downloads reach 50%/80% of the total; on the other hand, we compare the percentage of total downloads in 7 days, 30 days, and 100 days after publication. In general, papers are downloaded most frequently within a short time period right after their publication. And we find that compared with Non-Open Access papers, readers' attention on Open Access publications are more enduring. Based on the usage data of a newly published paper, regression analysis could predict the future expected total usage counts.Comment: 11 pages, 5 figures and 4 table

Research progress of exercise therapy for depressive disorder

Depressive disorder, as one of the major diseases in the world, has always received much attention for its prevention and treatment. As an emerging treatment, exercise therapy has optimistic application prospect with the advantages such as lower cost, fewer side effects and easier implementation, compared to conventional treatments such as drug therapy and physical therapy. Relevant studies have explored the mechanism of exercise in the treatment of depressive disorder, but the mechanism is not clear yet, which may involve improving the levels of neurobiochemical molecules, inhibiting inflammatory response, regulating neuroendocrine system, improving neuroplasticity, and other aspects. Exercise therapy has been proved to have similar biological effects with antidepressants, and may have overlapping effects with other treatments. Early intervention can benefit both non- diseased and already diseased populations to a certain extent. At present, there is still a gap in the clinical field related to exercise therapy for depressive disorder, and there are few high-quality studies. The design of exercise therapy plans is still in the exploratory stage, and there is no consensus on the design of exercise therapy plans. Additionally, there is a lack of relevant exercise therapy guidelines for clinicians to refer to. This review systematically introduces the biological mechanism of exercise therapy for depressive disorder, summarizes the clinical research results in this field carried out at home and abroad, and analyzes the current program and advantages and disadvantages of exercise therapy, in order to provide reference for the in-depth development of the exercise therapy researches

Alternative route strategy for emergency traffic management based on ITS: A case study of Xi’an Ming city wall

Interventno upravljanje prometom zahtijeva integraciju strategija koje obuhvaćaju napredno prikupljanje /širenjenje informacija o pogreškama, i učinkovit sustav emitiranja poruka. Približni "stalni" alternativni pravci koji kombiniraju inteligentne mjere transportnog sustava mogli bi objektivno igrati važnu ulogu u podržavanju kategorije ublažavanja posebnog zagušenja i upravljanja incidentima. Ovaj rad pokušava riješiti metodologiju davanja prioriteta takvim "stalnim" alternativnim pravcima preko glavnih generatora / atraktora prometa za strategije navođenja i preusmjeravanja prometa u odgovarajućoj lokalnoj mreži. Demonstrira se scenarij interventnog upravljanja i rada kako bi se razmotrili prikupljeni stvarni podaci o prometu, procjeni mjesta i trajanja incidenta, identifikaciji alternativnih pravaca i uzroku zagušenja integrirani sa ITS (Inteligentnim Transportnim Sustavima), koristeći mješovitu mrežu blizu gradskih zidina Xi\u27an Minga kao VISSIM primjera. Konačno, razmatraju se vrste vodećih znakova dijagramske rute s uzorcima primjene.Emergency traffic management calls for integration of strategies covering advanced information collecting/disseminating fallibilities, and effective message broadcast system. Approximate "permanent" alternate routes combining intelligent transportation system measures could objectively play a vital role in supporting the category of specific congestion alleviation and incident management. This paper attempts to address a methodology of prioritizing such "permanent" alternate routes via major traffic generators/attractors for route guidance and traffic diversion strategies in the concerned local network. A scenario of emergency management and operation is demonstrated to discuss the collection of real-time traffic data, location and duration evaluation of incident, identification of alternative routes and congestion evocation integrated with ITS, using a mixed network near Xi’an Ming City Wall as a VISSIM example. Finally, types of diagrammatic route guiding signs are addressed with application samples

Joint relay scheduling, channel access, and power allocation for green cognitive radio communications

PublishedJournal Article© 1983-2012 IEEE. The capacity of cognitive radio (CR) systems can be enhanced significantly by deploying relay nodes to exploit the spatial diversity. However, the inevitable imperfect sensing in CR has vital effects on the policy of relay selection, channel access, and power allocation that play pivotal roles in the system capacity. The increase in transmission power can improve the system capacity, but results in high energy consumption, which incurs the increase of carbon emission and network operational cost. Most of the existing schemes for CR systems have not jointly considered the imperfect sensing scenario and the tradeoff between the system capacity and energy consumption. To fill in this gap, this paper proposes an energy-aware centralized relay selection scheme that takes into account the relay selection, channel access, and power allocation jointly in CR with imperfect sensing. Specifically, the CR system is formulated as a partially observable Markov decision process (POMDP) to achieve the goal of balancing the system capacity and energy consumption as well as maximizing the system reward. The optimal policy for relay selection, channel access, and power allocation is then derived by virtue of a dynamic programming approach. A dimension reduction strategy is further applied to reduce its high computation complexity. Extensive simulation experiments and results are presented and analysed to demonstrate the significant performance improvement compared to the existing schemes. The performance results show that the received reward increases more than 50% and the network lifetime increases more than 35%, but the system capacity is reduced less than 6% only.This work was supported by the National Natural Science Foundation of China under Grants 61201219, 61171111, 61472150, and 61173045 and in part by the Fundamental Research Funds for the Central Universities under Grant 2013QN122

Fatal motor vehicle crashes on road segments in Harbin, China: combining rates into contributory factors

In spite of recent advances in traffic surveillance technology and ever-growing concerns over the safety performance improvement, there have been very few conclusive research efforts addressing the segment-involved traffic crashes. This research aims at evaluating the segment-involved crashes using 10 years of documented crash data (2000–2010) in Harbin. The interactions of crash patterns, distribution features, injury severity and potential causes are explored by mining a variety of contributory factors associated with driver demographics, roadway geometric design, environmental state, distribution of traffic flow, etc. Results show that different crash patterns are correlated with a number of risk factors at different roadway locations such as the driver's age and experience, weather, with or without median/division, number of lane, deviation of travelling speed, Annual Average Daily Traffic (AADT), volume to capacity ratio (v/c), and so on, and different combinations of factors may lead to some specific crash patterns such as head-on, angle or rear-end collisions. Moreover, four black locations with a huge number of crashes are identified due to heavy truck involvement on these in/out roads. These findings will help to better understand what, when and why these crashes occur and develop more targeted and cost-effective countermeasures to enhance the overall safety performance of the roadway network

A traffic fundamental diagram calibrating methodology to avoid unbalanced speed–density observations

Traffic fundamental diagram is extremely important to analyse traffic flow and traffic capacity, and the central part of traffic fundamental diagram is to calibrate speed–density relationship. However, because of unbalanced speed–density observations, calibrating results using Least Square Method (LSM) with all speed–density points always lead to inaccurate effect, so this paper proposed a selecting data sample method and then LSM was used to calibrate four well-known single-regime models. Comparisons were made among the results using LSM with all speed–density points and the selecting data sample. Results indicated that the selecting data sample method proposed by this paper can calibrate the singleregime models well, and the method overcomes the inaccurate effect caused by unbalanced speed–density observations. Data from different highways validated the results. The contribution of this paper is that the proposed method can help researchers to determine more precise traffic fundamental diagram

Physical health and cognitive function independently contributed to functional disability among Chinese older adults: Data from two asian metropolises

10.4061/2011/960848Journal of Aging Research20111-

The Concept of Drug-Resistant Epileptogenic Zone

Resective surgery is the most effective way to treat drug-resistant epilepsy. Despite extensive pre-surgical evaluation, only 30–70% patients would become seizure-free after surgery. New approaches and strategies are needed to improve the outcome of epilepsy surgery. It is commonly observed in clinical practice that antiepileptic drugs (AEDs) could maintain seizure freedom in a large proportion of patients after surgery, who were uncontrolled before the operation. In some patients cessation of AEDs leads to seizure recurrence which, in most cases, can be controlled by resuming AEDs. These observations suggest that the surgery has converted the epilepsy from drug-resistant to drug-responsive, implying that the operation has removed the brain tissue accounting for pharmacoresistance, rather than the pathological substrate of epilepsy (at least not completely). Based on these observations, it is hypothesized that there is a drug-resistant epileptogenic zone (DREZ) which overlaps with the epileptogenic zone (EZ), and has both epileptogenic and drug-resistant properties. DREZ is necessary and sufficient to cause drug-resistant epilepsy, and its remove would render the epilepsy drug-responsive. Testing the hypothesis requires the development of new methods to define the DREZ, which may be used to guide surgical planning when the epileptogenic zone cannot be completely excised. This concept can also help understand the mechanisms of drug-resistant epilepsy, leading to new therapeutic strategies