Search

The knowledge graph (KG) is widely used in various fields recently, while there are few achievements of knowledge graph related to educational applications. In this paper, some subject knowledge graphs are constructed to adapt to the educational development in big data environment, and the relationships between knowledge nodes are analyzed in order to provide students with a personalized online teaching for knowledge learning. Specially, a knowledge graph on python subject is constructed based on the neo4j graph database for students in programing courses. With three applications achieved on the knowledge graphs, the experimental results show that the knowledge points to students is described more clearly, and the logical relationships between the knowledge points are inferred according to the queries from students. It is verified that the knowledge graph on course learning performs significant effectiveness and efficiency in personalized online teaching.

Background The profiles of liver function abnormalities in COVID‐19 patients need to be clarified. Methods In this retrospective study, consecutive COVID‐19 patients over 60 years old in Renmin Hospital of Wuhan University from Jan 1 to Feb 6 were included. Data of demographics, clinical characteristics, comorbidities, laboratory tests, medications and outcomes were collected and analyzed. Sequential alterations of serum alanine aminotransferase (ALT) were monitored. Results 330 patients were included and classified into two groups with normal (n=234) or elevated ALT (n=96). There were fewer females (40.6% vs 54.7%, P=0.020) and more critical cases (30.2% vs. 19.2%, P=0.026) in patients with elevated ALT compared to the normal group. Higher levels of bacterial infection indices (e.g. white blood cell count, neutrophil count, C‐reactive protein and procalcitonin) were observed in the elevated group. Spearman correlation showed that both ALT and AST levels were positively correlated with those indices of bacterial infection. No obvious effects of medications on ALT abnormalities were found. In patients with elevated ALT, most ALT elevations were mild and transient. 59.4% of the patients had ALT concentrations of 41–100 U/L, while only a few patients (5.2%) had high serum ALT concentrations above 300 U/L. ALT elevations occurred at 13 (10–17) days and recovered at 28 (18–35) days from disease onset. For most patients, the elevation of serum ALT levels occurred at 6–20 days after disease onset and reached their peak values within a similar time frame. The recovery of serum ALT levels to normal frequently occurred at 16–20 days or 31–35 days after disease onset. Conclusions Liver function abnormalities were observed in 29.1% of the elderly COVID‐19 patients, which were slightly and transient in most cases. Liver function abnormalities in COVID‐19 may be correlated with bacterial infection.

With the rapid development of online courses, the requirements of personalized course recommendation have been increasing. The traditional collaborative filtering algorithm confronts with the challenge of cold start, which is difficult to settle on online course recommendation effectively. In this paper, we propose a novel click through rate (CTR) model for personalized online course recommendation, with discriminative user features, item features and cross features. The feature representation ability of the CTR model is improved and the serious challenge of cold start is alleviated. Furthermore, transfer learning is introduced to deal with the problem of insufficient data in models training. More specially, eye tracking technology is applied to capture the users’ cognitive styles, which are visualized with the heat map and fixation point trajectory. Finally, the recommendation interface sent to the learners, according to the user’s cognitive style. The experiments show that the novel CTR model improves the performance of the personalized online course recommendation.

During the period of COVID-19 epidemic situation, in order to ensure that students can study normally, the Ministry of Education has issued measures to “suspend classes without stopping learning”. Therefore, the traditional forms can’t meet the needs of learners, more and more people like online education. The existing online learning platforms cannot perfectly meet the learning needs of students, so the students need an online learning system that can meet their individual needs and improve learning efficiency. This article introduces an intelligent learning companion system, the system based on the advantages of WeChat Mini Programs can help learners achieve online learning and meet personalized needs.

In recent years, vocational education has attracted more and more attention. Teaching evaluation, as a test of teaching effect, is one of the vital factors to promote the development of vocational education. Therefore, it is very necessary to sort out the current teaching evaluation in the field of vocational education in China. In this paper, we will use literature metrology method and CiteSpace to analyze the data from China National Knowledge Infrastructure (CNKI) from 2010 to 2019. The development and hot spots of teaching evaluation in vocational education field are excavated by the visualizations on knowledge maps, which include the key words co-occurrence map, the author cooperation map and the organization cooperation map. Then, based on the current situation of online teaching, this paper analyzes the teaching evaluation from the micro aspect. Finally, the development of teaching evaluation in the future is predicted.

We report a tunable terahertz (THz) metamaterial absorber (MA) actuated by thermomechanical bimaterial microcantilevers. The THz MA, which is suspended on a silicon substrate by the bimaterial microcantilevers, is a sandwich structure with a bottom Al ground plane, middle air and SiNx dielectric layers, and a top Al rotationally symmetric open split ring resonator. Upon application of a current, a Ti heating resistor integrated on the SiNx dielectric layer induces the bimaterial microcantilevers to bend, causing the air layer thickness to change, modulating the absorption of the THz MA. The tunable THz MA exhibited a relative modulation depth of absorption of 28.1% at 0.69 THz and a thermomechanical sensitivity of 0.12°/K. This tunable THz MA has potential applications in filtering, modulation, control, and THz imaging.

Sleep-related diseases seriously affect the life quality of patients. Sleep stage classification (or sleep staging), which studies the human sleep process and classifies the sleep stages, is an important reference to the diagnosis and study of sleep disorders. Many scholars have conducted a series of sleep staging studies, but the correlation between different sleep stages and the accuracy of classification still needs to be improved. Therefore, this paper proposes an automatic sleep stage classification based on EEG. By constructing an improved empirical mode decomposition and K-means experimental model, the concept of “frequency-domain correlation coefficient” is defined. In the process of feature extraction, the feature vector with the best correlation in the time-frequency domain is selected. Extraction and classification of EEG features are realized based on the K-means clustering algorithm. Experimental results demonstrate that the classification accuracy is significantly improved, and our proposed algorithm has a positive impact on sleep staging compared with other algorithms.

The development of Internet of Things (IoT) and Mobile Edge Computing (MEC) has led to close cooperation between electronic devices. It requires strong reliability and trustworthiness of the devices involved in the communication. However, current trust mechanisms have the following issues: (1) heavily relying on a trusted third party, which may incur severe security issues if it is corrupted, and (2) malicious evaluations on the involved devices which may bias the trustrank of the devices. By introducing the concepts of risk management and blockchain into the trust mechanism, we here propose a blockchain-based trust mechanism for distributed IoT devices in this paper. In the proposed trust mechanism, trustrank is quantified by normative trust and risk measures, and a new storage structure is designed for the domain administration manager to identify and delete the malicious evaluations of the devices. Evidence shows that the proposed trust mechanism can ensure data sharing and integrity, in addition to its resistance against malicious attacks to the IoT devices.

Introduction Our recent study found that selective ablation of the distal part of the ligament of Marshall (LOMLSPV ) could suppress ventricular arrhythmias (VAs) during acute myocardial infarction (AMI). This study was to investigate the possible underlying mechanisms. Methods Dogs were randomly divided into the sham-operated group (SO; n = 6), AMI group (AMI; n = 8) and the group undergoing LOMLSPV ablation ahead of AMI (LOMD+AMI; n = 8). Incidence of VAs, serum levels of malondialdehyde (MDA) and superoxide dismutase (SOD), expression of connexin (Cx43), Bcl-2, Bax, caspase-3, tumor necrosis factor (TNF)-α, interleukin-6 (IL-6), and high mobility group box (HMGB)1 were compared. Anatomic and immunostaining examinations of LOM LSPV were performed. Results Compared with the AMI group, incidence of VAs was reduced in the LOMD+AMI group. Compared with the SO group, Cx43, SOD, and Bcl-2 were decreased, MDA, Bax, caspase-3, TNF-α, IL-6, and HMGB1 were increased in the MI group, and all the alterations were significantly restrained in the LOMD+AMI group. A visual nerve fiber communication between the left stellate ganglion (LSG) and LOM and abundant sympathetic nerve bundles distribution in LOMLSPV were revealed. Conclusions LOMLSPV ablation could suppress VAs during AMI. The possible mechanism may be associated with disconnection of the sympathetic conduit from LSG to the ventricles. Preservation of Cx43, inhibition of cardiac oxidative stress, apoptosis, and inflammation may be involved.

BACKGROUND Atrial ganglionated plexus (GP) ablation was proved to have therapeutic effects on vasovagal syncope. The study aimed to investigate whether selective ablation of only right anterior GP (ARGP) and right inferior GP (IRGP) was effective in a canine model of vasovagal syncope. METHODS Seventeen mongrel dogs were divided into control (N = 10) and ablation group (N = 7). Bilateral thoracotomy was performed at the fourth intercostal space and ARGP and IRGP were ablated in the ablation group. A bolus of veratridine (15 ug/kg) was injected into the left atrium to induce vasovagal reflex. Surface electrocardiogram and blood pressure (BP) were continuously monitored. Heart rate (HR) variability was calculated to represent cardiac autonomic tone. RESULTS Veratridine injection induced vasovagal reflex in all dogs. HR decreased from 149 ± 17 to 89 ± 33 beats/min (P

The sandwich-like 2H MoS2 and unilaminar graphitic nanocarbon hybrid was synthesized via graphitizing threonic acid intercalated MoS2 precursor obtained using hydrothermal process. An excellent electrocatalytic efficiency of hydrogen evolution reaction with a remarkably small overpotential of 195 mV and a Tafel slope of 47 mV/decade is easily accessible for our hybridized catalyst in 0.5 M H2SO4 aqueous solution, much superior to that of pure 2H MoS2 and threonic acid intercalating MoS2 nanomaterials. Moreover, the detailed electrochemical activity surface area and electrochemical impedance suggest that the face-to-face stacking of unilaminar 2H MoS2 and graphitic nanocarbon at an alternating sequence accelerates the mass transport and electron transfer and, thus, enhances the efficiency for electrocatalytic water splitting. This work paves a neoteric and straightforward pathway for the fabrication of superlattice MoS2 and unilaminar graphitic nanocarbon hybrid, further improving the electrocatalytic effi...

INTRODUCTION Cardiac sympathetic activation facilitates atrial electrical remodeling during atrial fibrillation (AF). Selective ablation of the distal part of the ligament of Marshall (LOMLSPV ) could decrease cardiac sympathetic innervation. This study aimed to investigate the effects of LOMLSPV ablation on atrial electrical remodeling in a short-term rapid atrial pacing (RAP) model. METHODS In 16 anesthetized dogs, 6 hours of RAP (20 Hz, 2 × threshold) was delivered before LOMLSPV ablation (group 1, N = 8) or after (group 2, N = 8). Heart rate variability (HRV), serum norepinephrine (NE), atrial electrophysiological indices were analyzed. Six times of burst pacing (20 Hz, 2 × threshold, lasting for 5 seconds, were performed to induce AF, the number of episodes and the duration of AF were compared. RESULTS LOMLSPV ablation decreased sympathetic indices of HRV and serum NE. Atrial effective refractory period (ERP) was shortened during RAP in both groups with higher reduction degrees in group 1. In group 1, the shortening of atrial ERP, elevating of ERP dispersion and sum of window of vulnerability (ΣWOV), facilitating of AF induced by RAP were subsequently reversed by LOMLSPV ablation. In group 2, LOMLSPV ablation prolonged atrial ERP, decreased ΣWOV, eliminated AF induction. The subsequent RAP failed to alter these indices. Histological studies showed abundant sympathetic nerve fibers in LOMLSPV . CONCLUSION LOMLSPV ablation could inhibit atrial electrical remodeling during short-term RAP by reducing the cardiac sympathetic activity. LOMLSPV may be a potential target in AF ablation, especially in patients with highly cardiac sympathetic activation or atrial electrical remodeling.

Clustering by fast search and find of density peaks (DPC) is a new clustering method that was reported in Science in June 2014. This clustering algorithm is based on the assumption that cluster centers have high local densities and are generally far from each other. With a decision graph, cluster centers can be easily located. However, this approach suffers from certain disadvantages. First, the definition of the local density and distance measurement is too simple; therefore, the DPC algorithm might perform poorly on complex datasets that are of multiple scales, cross-winding, of various densities, or of high dimensionality . Second, the one-step allocation strategy is not robust and has poor fault tolerance. Thus, if a point is assigned incorrectly, then the subsequent allocation will further amplify the error, resulting in more errors, which will have a severe negative impact on the clustering results . Third, the cutoff distance dc is generally difficult to determine since the range of each attribute is unknown in most cases. Even when being normalized or using the relative percentage method, a small change in dc will still cause a conspicuous fluctuation in the result, and this is especially true for real-world datasets. Considering these drawbacks, we propose a shared-nearest-neighbor-based clustering by fast search and find of density peaks (SNN-DPC) algorithm. We present three new definitions: SNN similarity, local density ρ and distance from the nearest larger density point δ . These definitions take the information of the nearest neighbors and the shared neighbors into account, and they can self-adapt to the local surroundings. Then, we introduce our two-step allocation method: inevitably subordinate and possibly subordinate. The former quickly and accurately recognizes and allocates the points that certainly belong to one cluster by counting the number of shared neighbors between two points. The latter assigns the remaining points by finding the clusters to which more neighbors belong. The algorithm is benchmarked on publicly available synthetic datasets , UCI real-world datasets and the Olivetti Faces dataset, which are often used to test the performance of clustering algorithms. We compared the results with those of DPC, fuzzy weighted K-nearest neighbors density peak clustering (FKNN-DPC), affinity propagation (AP), ordering points to identify the clustering structure (OPTICS), density-based spatial clustering of applications with noise (DBSCAN), and K-means. The metrics used are adjusted mutual information (AMI), adjusted Rand index (ARI), and Fowlkes–Mallows index (FMI). The experimental results prove that our method can recognize clusters regardless of their size, shape, and dimensions; is robust to noise; and is remarkably superior to DPC, FKNN-DPC, AP, OPTICS, DBSCAN, and K-means.

Single-silicon nanowire field-effect transistor (SiNW-FET) devices are powerful tools for the detection and quantification of biochemical molecules. However, traditional SiNW-FET-based biosensors demonstrate low output signals and high fluctuation noises, which results from the tiny scale of a single channel and electrical property deterioration caused by the dry etching process. To improve the performance of the SiNW-FET biosensors, here we developed a 3-D-SiNW-FET by using a hybrid process of deep reactive ion etching and isotropic wet etching with HF, HNO3 and HAc (HNA) mixed solution. The 3-D-SiNW-FET that included $5\times7$ nanowire channels with a wire diameter of approximately 300 nm was successfully fabricated with the novel hybrid process. Compared with the performance of single-and 2-D-SiNW-FETs, the 3-D-SiNW-FET showed a fairly good ability to stabilize and enhance the source-drain current by parallelizing the signals of the multiple channels. With the fabricated 3-D-SiNW-FET, immunoglobulin G was detected at a concentration as low as 5 fM. [2017-0102]

Surface-selective chemical modification of anatase TiO2 nanocrystals is performed in the post-discharge region of N2 microwave plasma and the chemical bonding states of surface nitrogen species are carefully evaluated using X-ray photoemission spectroscopy (XPS). It is found that the surface treatments in the afterglows induce the formation of stable nitrogen species at or near the surface of TiO2. Interestingly, the detailed bonding structure varies strongly depending on the afterglow condition. In pure N2 afterglows, various N species with a direct Ti N bond are formed on the surface, while the use of N2-O2 mixtures induces the formation of additional oxidized species of NO3− on the surface. This is attributed to the high concentrations of O or NO in the afterglows of N2-O2 plasmas. The incorporation of substitutional N species in the subsurface is also achieved after a prolonged exposure in the early afterglow with a high density of N2+ species. Our results show that the exposure condition can be controlled for a selective chemical modification of TiO2 surface for the control of surface properties in various applications.

Individuals predisposed to vasovagal syncope may have different autonomic nervous system control mechanisms from those without predisposition to vasovagal events. To test this hypothesis, we investigated different sympathetic responses in a canine model of vasovagal syncope. Left thoracotomy was performed on 20 mongrel dogs. The heart was exposed and a bolus of veratridine (15 μg/kg), a neurotoxin which prevents the inactivation of sodium ion channels, was injected into the left atrium to induce a Bezold–Jarisch reflex-mediated vasovagal event, characterized by bradycardia, decreased inotropism, and hypotension. Electrocardiogram and blood pressure were continuously monitored. Neural activity was recorded from the left stellate ganglion. Plasma norepinephrine and acetylcholine levels were measured 30 s before and 30 s after veratridine injection. Veratridine resulted in rapid decreases in heart rate and blood pressure in all dogs, accompanied by increases in both norepinephrine and acetylcholine. Two types of neural activity (high-amplitude spike discharge activity and low-amplitude burst discharge activity) were recorded from the left stellate ganglion. Veratridine induced high-frequency spike discharge activity in some dogs (Group A), whereas spike discharge activity was scarce and relatively unresponsive to veratridine in the remaining dogs (Group B). Dogs in Group A had higher plasma norepinephrine levels (111.63 ± 15.1 vs. 48.11 ± 33.81 ng/l, p = 0.002) and less intense drops in heart rate (− 37 ± 24 vs. − 84 ± 28 bpm, p = 0.001) and blood pressure (systolic blood pressure, − 18 ± 15 vs. − 37 ± 13 mmHg, p = 0.009; diastolic blood pressure, − 26 ± 13 vs. − 45 ± 13 mmHg, p = 0.005) compared to dogs in Group B. Similarly, heart rate post-veratridine was higher (102 ± 23 vs. 69 ± 22 bpm, p = 0.004), the veratridine-induced longest RR interval was shorter (0.7 [0.5–0.8] vs. 1.2 [1.1–3.5] s, p

Background Heart failure (HF) is associated with autonomic dysfunction. Vagus nerve stimulation has been shown to improve cardiac function both in HF patients and animal models of HF. The purpose of this present study is to investigate the effects of ganglionated plexus stimulation (GPS) on HF progression and autonomic remodeling in a canine model of acute HF post-myocardial infarction. Methods and results Eighteen adult mongrel male dogs were randomized into the control (n = 8) and GPS (n = 10) groups. All dogs underwent left anterior descending artery ligation followed by 6-hour high-rate (180–220 bpm) ventricular pacing to induce acute HF. Transthoracic 2-dimensional echocardiography was performed at different time points. The plasma levels of norepinephrine, B-type natriuretic peptide (BNP) and Ang-II were measured using ELISA kits. C-fos and nerve growth factor (NGF) proteins expressed in the left stellate ganglion as well as GAP43 and TH proteins expressed in the peri-infarct zone were measured using western blot. After 6 h of GPS, the left ventricular end-diastolic volume, end-systolic volume and ejection fraction showed no significant differences between the 2 groups, but the interventricular septal thickness at end-systole in the GPS group was significantly higher than that in the control group. The plasma levels of norepinephrine, BNP, Ang-II were increased 1 h after myocardial infarction while the increase was attenuated by GPS. The expression of c-fos and NGF proteins in the left stellate ganglion as well as GAP43 and TH proteins in cardiac peri-infarct zone in GPS group were significantly lower than that in control group. Conclusions GPS inhibits cardiac sympathetic remodeling and attenuates HF progression in canines with acute HF induced by myocardial infarction and ventricular pacing.

Network embedding is an important pre-process for analysing large scale information networks. Several network embedding algorithms have been proposed for unsigned social networks. However, these methods cannot be simply migrate to signed social networks which have both positive and negative relationships. In this paper, we present our signed social network embedding model which is based on the word embedding model. To deal with two kinds of links, we define two relationships: neighbour relationship and common neighbour relationship, as well as design a bias random walk procedure. In order to further improve interpretation of the representation vectors, the follow-proximally-regularized-leader online learning algorithm is introduced to the traditional word embedding framework to acquire sparse representations. Extensive experiments were carried out to compare our algorithm with three state-of-the-art methods for community detection and sign prediction tasks. The experimental results demonstrate that our algorithm performs better than the comparison algorithms on most signed social networks.

TiO 2 -supported Pt catalysts were prepared for the study of CO oxidation kinetics at reaction conditions of pressures (1–100 Torr) and temperatures (300–500 K). We find two distinct temperature ranges with different reaction kinetics distinguished by an abrupt slope change at around 380 K in the Arrhenius plot only with the excess O 2 , not with the stoichiometric O 2 /CO ratio. We propose that Pt oxides are formed during the catalytic reactions with increasing temperatures under the oxidizing condition and the origin of the slope change is due to the changes in the reaction pathways of CO oxidation due to the Pt oxide formation.

SnS has a great potential for use as a photocatalyst for the production of chemical fuels out of sunlight. For the use of it as a photocatalyst, a fast and reliable method of fabricating pure layered crystalline SnS is required. Here, we present a simple and efficient method of fabricating high-quality SnS layers as a thin film on various substrates such as Si, quartz, glass and FTO. The nanodisk-shaped p-type SnS films are obtained starting from SnS2 via a one-step process involving phase dissociation and sulfur reduction. The prepared SnS films show interesting thickness-dependent physical properties such as optical band gap, absorption coefficient and flat band potential, which suggest the possibility of tuning its property by controlling the thickness. Especially, the SnS films with the thickness of 20 nm or less show an enhanced absorption above the band gap and an increased free carrier concentration. With such advantageous photoresponsive properties, we observed a good hydrogen production activity (order of 100 μmol h−1 cm−2) from the thin SnS films under photoelectrocatalytic reaction conditions. The measured efficiency in hydrogen evolution is explained from a favorable band alignment as well as the good photoresponse of the film. Combined with the facile fabrication of high-quality thin SnS films, our analysis shows that nanodisk-shaped SnS is a promising material for a future development of photocatalytic production of hydrogen as a chemical fuel.

In this paper, sensitive and specific detections on dimethyl methylphosphonate (DMMP), a representative simulant of sarin and organophosphorus pesticides, are demonstrated by a piezoresistive cantilever-based aptasensor in neutral electrolytic solution. By improving the design and fabrication processes of the cantilever-based sensor, a Hooge factor of 4.8 × 10−6 and a surface stress sensitivity of 1.47 × 10−3 (N/m)−1 have been obtained, and the output fluctuation has been minimized to 1 μV at a 3 V bias voltage. For selective and specific molecular capturing, the sensing cantilevers was functionalized by 78-mer 5′-biotinylated aptamers in a biotin-streptavidin system. The aptasensor was experimentally demonstrated to have a linear behavior in detecting DMMP within the concentrations of 50 nM–1.0 μM. Attributed to the low electrical noise and high sensitivity of the piezoresistive cantilever, a limit of detection of 50 nM for DMMP was well obtained in phosphate buffered saline at neutral pH value. Besides, the aptasensors were also exposed to apple juice with DMMP added, whose detecting results indicate that the existence of biomacromolecular polysaccharides and the regional desorption of mercapto self-assembled layer from the gold film on the sensing cantilevers could result in a decrease of the detecting sensitivity slightly. The proposed cantilevers are promising for low cost, trace level and on-site biological/chemical detections.

Vocational education is an important part in modern education and its teaching methods appear distinguishing characters. In recent years, the research on teaching models in vocational education has attracted great attention and obtained significant achievements. In this paper, the knowledge mapping software of CiteSpace is introduced to bibliometric analyze and study the hotspots in vocational education based on the data from the China National Knowledge Infrastructure (CNKI). With the visualizations on knowledge maps including institutional cooperation, author cooperation, keyword co-occurrence and time zone map, the development veins of vocational education is explored, the frontiers and research focus on vocational education are achieved. Finally, the research results are applied to practical teaching mode in the course of Python Programming. The results of the teaching practice show that studying passion is promoted and the effect of teaching are improved in the class with novel teaching mode.

In this work, we propose an ultrasensitive detection of aflatoxin B1 using a piezoresistive microcantilever biosensor, which is composed of doped piezoresistive layer, top polyimide (PI) passive layer and bottom silicon oxide (SiO 2 ) passive layer. Four microcantilevers with the same dimensions consist of a wheatstone bridge to achieve a higher sensitivity and better noise performance. The fabricated PI/Si/SiO 2 microcantilever shows a steady output with less than 1 μV@3V fluctuation in PBS buffer, while the spring constant is 21.307 nN/μm and the deflection sensitivity is 3.54×10-7 nm-1. Detections on aflatoxin B1 with a minimum concentration of 1 ng/mL were achieved.

Using masked priming paradigms, this study examined advanced Chinese EFL learners’ morphological generalization of en verb series compared with L1 learners. In Experiment 1, neither group of learners showed affixed or orthographic priming for suffixed words. However, both groups demonstrated priming in the prefixed condition (e.g., entitle/ENCOUNTER) relative to the orthographic (e.g., engineer/ENOUNTER) and the unrelated condition (e.g., museum/ENCOUNTER). For the L1 group, the difference between prefixed priming and repetition priming was not significant, while the L2 group's responses in the prefixed condition were significantly slower than those in the identity condition (e.g., encounter/ENCOUNTER). In Experiment 2, the prefixed pseudo en- verbs were primed by the prefixed real ones for both groups, but no suffixed priming was observed. Compared with the counterparts who hardly made errors in the LDT, the L2 group produced significantly more errors for the prefixed than for the suffixed ones. These results supported the left-to-right processing bias and indicated morphological generalization of prefixed en- verbs by Chinese EFL learners. The generalization, however, was not as automatic as that by native speakers. It may be attributed to Chinese EFL learners’ L1 transfer of phonetic representation.

This paper reports a novel infrared focal plane array (FPA) using SiN x /SiO2/SiN x sandwiched structure as the supporting frames for bimaterial cantilever pixels. The device was fabricated by a bulk silicon process, where a trench backfill technique was employed to form the SiN x /SiO2/SiN x sandwiched frames. By replacing the silicon frame with SiN x /SiO2/SiN x sandwiched frame, the fill factor of the FPA is increased to 42%. Compared with other substrate-free FPAs with frames making of a thin layer of SiN x , the sandwiched frame provides more supporting strength for the cantilever pixels. Meanwhile, the reliability and the uniformity of the FPA were improved with a design of staggered arrangement of cantilever pixels. Thermal images of human bodies were captured successfully at room temperature. A complete analysis of device performance was also carried out both theoretically and experimentally, including thermomechanical sensitivity, noise equivalent temperature difference, and response time. [2015-0261]

The analysis of the switch status of each unit module of a cascaded multi-level inverter reveals that the working condition of the switch of a chopper arm causes unnecessary switching under the conventional unipolar sinusoidal pulse width modulation (SPWM). With an increase in the number of cascaded multilevel inverters, the superposition of unnecessary switching gradually occurs. In this work, we propose an improved SPWM strategy to reduce switching in cascaded multilevel inverters. Specifically, we analyze the switch state of the switch tube of a chopper arm of an H-bridge unit. The redundant switch is then removed, thereby reducing the switching frequency. Unlike the conventional unipolar SPWM technique, the improved SPWM method greatly reduces switching without altering the output quality of inverters. The conventional unipolar SPWM technique and the proposed method are applied to a five-level inverter. Simulation results show the superiority of the proposed strategy. Finally, a prototype is built in the laboratory. Experimental results verify the correctness of the proposed modulation strategy.

Objectives The goal of this study was to investigate the effect of selective ablation of the ligament of Marshall (LOM) on ventricular arrhythmias (VAs). Background Previous studies have shown that selective stimulation of sympathetic elements of the LOM, the distal segment of the ligament of Marshall that extends beyond the left superior pulmonary vein (LOM LSPV ), might induce VAs. Methods In protocol 1, the blood pressure and ventricular effective refractory period changes as a response to LOM LSPV stimulation and left stellate ganglion (LSG) stimulation were measured before and after LOM LSPV ablation in 8 anesthetized dogs. In protocol 2, a total of 24 dogs were randomly divided into group 1 (cesium alone, n = 8), group 2 (cesium combined with LSG stimulation, n = 8), and group 3 (cesium combined with LSG stimulation after LOM LSPV ablation, n = 8). Early afterdepolarization amplitude, VA prevalence, and the tachycardia threshold (measured according to the dose of cesium administered) were compared among the groups. Results In protocol 1, both LOM LSPV stimulation and LSG stimulation significantly increased blood pressure and shortened the ventricular effective refractory period, both of which were significantly attenuated by LOM LSPV ablation. In protocol 2, compared with group 1, the prevalence of VAs and the early afterdepolarization amplitudes were significantly augmented in group 2 and were maintained at a comparable level in group 3. Furthermore, the tachycardia threshold in group 2 (0.625 mmol/kg) was significantly lower than that noted in groups 1 and 3 (both 1.000 mmol/kg; p Conclusions LOM LSPV ablation reduced the prevalence of the VAs induced by cesium in combination with LSG stimulation, and the antiarrhythmic effect may involve the blockade of the sympathetic conduit between the LSG and the ventricles.

A biosensor with mirror microcantilevers, based on silicon-on-insulator (SOI) was designed and fabricated for biochemical detection. For measuring the extremely low deflections of the microcantilevers, a high precision optical readout approach based on a fiber optical reflective light intensity readout approach were presented. The results demonstrate that microcantilever biosensor has very high sensitivity of 6.26908 mV/nm, and the measurement resolution is up to 0.1998 nm. In the practical measure glucose solution concentration experiments, the results demonstrate that the sensitivity is up to 1.19 mV/μg/ml.

An approach named Windowed XOR photography is proposed for optical readout bimaterial cantilever focal plane array (FPA) imaging. It can replace the conventional differential amplifying method for separating the target from the background radiation. Compared with the conventional method, the approach is helpful to reducing image data's bit-width for processing, avoids negative values and data overflow. A novel integrated aspheric optical readout system and digital processing system were developed to evaluate the approach. Comparative infrared imaging experiments were conducted. The results and analyses show that the Windowed XOR photography has preferable effect and performance.

We aimed to understand the evaluation of different Bowie-Dick test (B-D test) on the performance of pressure steam sterilization equipment in the case of simulated gas leakage, and we selected a pulsating vacuum steam sterilizer to set 4 different gas leakage levels: 1.1, 1.3, 1.5, and 1.7 mbar/min during the B-D test phase. In terms of methods, 4 different brands of B-D test kits (devices) were tested at 4 different leakage rates, and a total of 48 experiments were conducted. The results from univariate analysis revealed that there are statistically significant differences in the judgment of test results among different personnel and brands. The results from multivariate logistic regression analysis displayed that the difference between different personnel was statistically significant (χ2 = 45.34, P .05). Result judgments of brand 1 and brand 2 are susceptible to subjective factors. The judgment of brand 3 is intuitive and consistent with the evaluation result of brand 4. In conclusion, the order of capacity to evaluate air leakage from best to worst is brand 4→brand 3→brand 1→brand 2.

Criminals can launder crypto-currencies through mixing coins, whose original purpose is preservation of privacy in the presence of traceability. Therefore, it is essential to elaborately design mixing polices to achieve both privacy and anti-money laundering. Existing work on mixing policies relies on the knowledge of a blacklist. However, these policies are paralysed under the scenario where the blacklist is unknown or evolving. In this paper, we regard the above scenario as games under incomplete information where parties put down a deposit for the quality of coins, which is suitably managed by a smart contract in case of mixing bad coins. We extend the poison and haircut policies to incomplete information games, where the blacklist is updated after mixing. We prove the existence of equilibria for the improved polices, while it is known that there is no equilibria in the original poison and haircut policies, where blacklist is public known. Furthermore, we propose a seminal suicide policy: the one who mixes more bad coins will be punished by not having the deposit refunded. Thus, parties have no incentives to launder money by leveraging mixing coins. In effect, all three policies contrast money laundering while preserving privacy under incomplete information. Finally, we simulate and verify the validity of these policies.

The task of the bilingual dictionary is to provide lexical units in the source language with equivalents in the target language. Therefore, translation equivalence is of great importance in compiling a bilingual dictionary. This study is an introduction to categories of equivalence in bilingual dictionaries and the causes of non-equivalence. Some methods for translating non-equivalence are also recommended.

English teachers at junior middle schools often employ traditional vocabulary teaching techniques such as L1 equivalents, word lists, pictures, and word formation rules. They reinforce the students' retention of vocabulary by asking them to read aloud the words repeatedly and copy the new words as homework. In this study, suggestions are given to improve English vocabulary teaching techniques at junior middle schools.

The hybridized electrocatalysts constituted by binary 3d transition nanoparticles with a varied ratio of Fe to Ni were successfully synthesized through a two-step fabrication procedure, a homogeneous precipitation process, and a successive graphitization process. A superior oxygen evolution reaction (OER) efficiency with a yielded remarkable low overpotential of ∼0.26 V and a Tafel slope of ∼56 mV/decade is achieved for the heterostructured Fe1Ni2 nanoparticles coated by graphitic nanocarbon in a 1 mol/L KOH solution. The influencing factors for synthesizing the electrocatalysts, such as the graphitization temperature, the content of iron and the thickness of the carbon shells are also carefully investigated, and improved electrocatalytic efficiency is achieved with appropriate fabrication parameters for the hybridized catalysts. It is considered that the synergistic effect of the defects and electrochemical conductivity of the graphitic carbon shells shows great influences on the electrocatalytic activity. In addition, the detailed electrochemically active surface area and the electrochemical impedance suggest that the FexNiy hybrids coated by graphitic nanocarbon have improved the mass transport and electron transfer rate, resulting in an enhanced electrocatalytic water splitting efficiency. This work opens up a new way to fabricate promising oxygen-evolving catalysts with high-efficiency and low-cost.

Internet of Things (IoT) devices strive to maximize their utilities and preserve security of IoT system within limited capacity. In effect, these kinds of devices can be resumed to be rational devices toward the view of game theory. Previous utilities inherit the definitions deriving from quintessential games (e.g. prisoner's dilemma game). However, they are criticized for either arbitrary or elaboration. In this paper, we circumvent the criticism by devising a new utility function based on beliefs and entropy, which are extracted from IoT devices (e.g. signals). The new utility function dwarfs others in terms of practicability. In addition, we present a general rational information exchange protocol and define the utilities based on entropy formally especially in the key round. Furthermore, we compare the utilities with existing ones with similar conclusions. That is, our formal utility definitions are equivalent to previous ones. To the best of our knowledge, it's the first time to relate utilities with entropy and meanwhile achieve desirable security properties.

Urban street networks derive their complexity not only from their hierarchical structure, but also from their tendency to simultaneously exhibit properties of both grid-like and tree-like networks. Using topological indicators based on planning parameters, we develop a method of network division that makes classification of such intermediate networks possible. To quantitatively describe the differences between street network patterns, we first carefully define a tree-like network structure according to topological principles. Based on the requirements of road planning, we broaden this definition and also consider three other types of street networks with different microstructures. We systematically compare the structure variables (connectivity, hierarchy, and accessibility) of selected street networks around the world and find several explanatory parameters (including the relative incidence of through streets, cul-de-sacs, and T-type intersections), which relate network function and features to network type. We find that by measuring a network&rsquo, s degree of similarity to a tree-like network, we can refine the classification system to more than four classes, as well as easily distinguish between the extreme cases of pure grid-like and tree-like networks. Each indicator has different distinguishing capabilities and is adapted to a different range, thereby permitting networks to be grouped into corresponding types when the indicators are evaluated in a certain order. This research can further improve the theory of interaction between transportation and land use.

Basic public cultural services are based on the consensus of contemporary Chinese social development, and are provided by the government according to the current economic and social development stage and overall level, and are designed to protect citizens’ basic cultural rights and interests. Basic public cultural services meet the basic cultural needs of the public and are therefore closely related to citizens’ rights in cultural life. Especially under the goal of building a service-oriented government, in recent years China has continuously deepened its emphasis on the equalization of basic public cultural services provided by the government. Jiangxi Province, as an underdeveloped region in China, has obvious differences in basic public cultural services in different cities. The article combines the relevant statistical data of basic public cultural services in various cities in Jiangxi Province from 2016 to 2018 to calculate the equalization coefficient and coefficient of variation of basic public cultural services in Jiangxi Province, and measures the basic situation of 11 cities and measures between different cities The relative gap in the equalization of basic public cultural services. The research shows that the unequal characteristics of basic public cultural services among cities in Jiangxi Province are very obvious. In order to promote the rational allocation of resources in various cities in Jiangxi Province, narrow the gap between cities and cities, and achieve the equalization of high-quality and sustainable basic public cultural services, it is necessary to promote coordinated development between regions, establish a multi-input mechanism, and strengthen the construction of talents for basic public cultural services, improve the basic public cultural service infrastructure construction.