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Design and microwave measurement of a linearly polarized circular TE11 mode coupler are reported in this article. Based on our earlier designed input coupler with smooth wall, we proposed an improved structure with ridges loading resulting in a bandwidth up to 29.2%. Simulation results show the port reflection ${S}_{11}$ less than −10 dB is in 7.9–10.6 GHz. And the split transmission ${S}_{21}$ and $S_{31}$ are over −3.4 dB in this frequency range. According to the simulation results, the designed input coupler is fabricated and measured with the vector network analyzer. The measurement results show excellent performance, which is in good agreement with the simulation when the conductor loss is taken into consideration. In addition, an input coupler with a cutoff waveguide is designed to improve the efficiency of single-port transmission and the power utilization. Simulation results show the transmission efficiency of the single port achieves 91%.

Background Hepatocellular carcinoma (HCC) is the third leading cause of cancer mortality worldwide. Increasing evidence indicates a close relationship between HCC and the human microbiota. Herein, we reviewed the important potential of the human microbiota as a diagnostic biomarker of HCC. Data sources Several innovative studies have investigated the characteristics of the gut and oral microbiomes in patients with HCC and proposed that the human microbiome has the potential to be a diagnostic biomarker of HCC. Literature from February 1999 to February 2019 was searched in the PubMed database using the keywords “microbiota” or “microbiome” or “microbe” and “liver cancer” or “hepatocellular carcinoma”, and the results of clinical and experimental studies were analyzed. Results Specific changes occur in the human microbiome of patients with HCC. Moreover, the gut microbiome and oral microbiome can be used as non-invasive diagnostic biomarkers for HCC. Furthermore, they also have certain diagnostic potential for precancerous diseases of HCC. The diagnostic potential of the blood microbiota and ascites microbiota in HCC will be gradually discovered in the future. Conclusions The human microbiome is valuable to the diagnosis of HCC and provides a novel strategy for targeted therapy of HCC. The human microbiome may be widely used in the diagnosis, treatment and prognosis for multiple system diseases or cancers in the future.

The vortex beam with helical phase has great potential in detecting rotating targets. Offset, inclination and even the optical axis not in the same plane with the rotational axis often exist between the beam and the rotational axis when the non-cooperative rotating target is measured by vortex beam. To effectively measure rotational speed and eccentric distance (the distance of facula center and the center of rotation on the object being detected) of non-cooperative object, according to the scattering point model and rotational Doppler effect principle, this paper proposes a geometric projection method to study the detection problem about the incidence of the beam at arbitrary position relative to the object’s rotational axis, and analyzes the change of rotational Doppler frequency shift in the state of existing both offset and inclination, and obtains the rule of the extremum of the rotational Doppler frequency shift changing with the relative space position parameters. On this basis, the rotational speed and the eccentric distance are obtained when both eccentricity and inclination exist and the optical axis of vortex has no deflection. And a method for detecting the rotational speed and the eccentric distance of non-cooperative target is proposed. The conclusions obtained in this paper have some guiding significance for further application of rotational speed detection technology based on vortex beam.

When using a hand-held 3D laser scanner to collect target object data, due to factors such as personnel operation, collection environment and equipment itself, a large number of external noise points are often produced. This will seriously affect the processing and reconstruction accuracy of later point cloud data. According to the data analysis, these external noise points are divided into two categories: flying points and cluster points. Aiming at this phenomenon, a point cloud model noise removal algorithm combining statistical filtering and pass-through filtering is proposed. Firstly, the flying points are eliminated by statistical filtering, and then the remaining large area cluster points are removed by through filtering. The experimental results show that the algorithm can quickly and accurately identify external noise points and eliminate them completely.

In view of the deficiency in traditional bearing fault diagnosis which depended on manual diagnosis and mechanical theory, the deep learning fault detection method based on bearing fault data-driven was studied. By analyzing the advantages and disadvantages of convolutional neural networks (CNNs), recurrent neural networks (RNNs) and self-attention mechanism, a rolling bearing fault detection method based on CSAM was proposed, which effectively integrated the powerful feature processing ability of CNNs and the local feature processing ability of self-attention mechanism. Bearing fault detection models based on CNNs, RNNs and CSAM are respectively constructed. Typical rolling bearing fault experimental data sets were selected to compare and analyze the effect of the CSAM method and the existing algorithm for the classification and identification of bearing faults. The results shown that the fault identification rate of CSAM method was 29.2% and 9.5% higher than that of CNNs and RNNs respectively in the test dataset on which the bearing fault was determined, which verified that the method can significantly improve the accuracy of bearing fault detection.

To address the challenge of high water consumption, massive wastewater discharge and high pollution risk in textile industries, different countries have chosen various treatment method for textile wastewater according to the location and management of textile enterprises. It is not economical purposely to build separate wastewater treatment plants (WWTPs) for each small-scale enterprise, hence, it is common to treat the wastewater for a group of factories and then complete the treatment via a municipal wastewater treatment plant. However, the complex characteristics of textile wastewater brings some new problems for WWTPs: Textile wastewater contains over 300 mg/L COD, 100 μg/L antimony, 1000 μg/L aniline, some of which are toxic to microbes or non-biodegradable. Coagulation plays an important role in the pretreatment of textile wastewater for removing hydrophobic dyes, decreasing the SS and COD. In this paper, Poly Ferric Sulfate (PFS), Poly Aluminum Chloride (PAC) and Poly Aluminum Ferric Chloride (PAFC) were chosen to improve the biodegradability of the textile wastewater. And then, quantitatively evaluate the biodegradability of wastewater before and after coagulation treatment by analyzing the proportion of different organic pollution, which could be divided into four parts including rapid bio-treated, easy bio-treated, normal bio-treated and non-biological treatment. Results showed that the biodegradability of textile wastewater could be improved by coagulation process, and the contents of organic matter of rapid bio-treated and easy bio-treated could be maximizing when the control condition of coagulation process was optimized. Moreover, because of its characteristics of simple, easy to use, and rapidly online implement, this approach holds a great promise for applications such as investigate wastewater feature deeply, treatment technology optimization, risk control and management.

Postoperative pancreatic fistula (POPF) is a serious complication and results in prolonged hospitalization and high mortality. The present study aimed to evaluate the safety and effectiveness of total closure of pancreatic section for end-to-side pancreaticojejunostomy in pancreaticoduodenectomy (PD).This was a prospective randomized clinical trial comparing the outcomes of PD between patients who underwent total closure of pancreatic section for end-to-side pancreaticojejunostomy (Group A) vs those who underwent conventional pancreaticojejunostomy (Group B). The primary endpoint was the incidence of pancreatic fistula. Secondary endpoints were morbidity and mortality rates.One hundred twenty-three patients were included in this study. The POPF rate was significantly lower in Group A than that in Group B (4.8% vs 16.7%, P0.05). About 38.3% patients in Group B developed one or more complications; this rate was 14.3% in Group A (P0.01). The wound/abdominal infection rate was also much higher in Group B than that in Group A (20.0% vs 6.3%, P0.05). Furthermore, the average hospital stays of the two groups were 18 days in Group A, and 24 days in Group B, respectively (P0.001). However, there was no difference in the probability of mortality, biliary leakage, delayed gastric emptying, and pulmonary infection between the two groups.Total closure of pancreatic section for end-to-side pancreaticojejunostomy is a safe and effective method for pancreaticojejunostomy in PD.

This paper presents the self-adaptive phase compensation characteristics and quantitative design of an unsymmetrical current-sensing resistor for magnetically suspended flywheel (MSFW) system with strong gyroscopic effects. Aimed at the nutation stability of the MSFW control system, the self-adaptive phase compensation characteristics of PWM H-bridge unipolar switching power amplifiers with unsymmetrical current-sensing resistor with inductance variations is analyzed firstly, including the initial compensation frequency and compensation phase in the compensation working regions. Secondly, the quantitative safeguard-phase margin design method for the asymmetrical factor in H-bridge unipolar switching power amplifiers is proposed based on the nutation stability criterion. Finally, the influence of the unsymmetrical current-sensing resistance network on the nutation stability is further analyzed. Simulation and experimental results demonstrate the correctness and effectiveness of the proposed method.

Rare earth ions are considered as the ideal dopants to modify the crystal structure, electronics structure, and gas sensing performance of metal oxides semiconductors. In this paper, Ce-doped MoO3 nanobelts were successfully synthesized via a one-step hydrothermal method. The morphology and microstructure were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDS), and X-ray photoelectron spectra (XPS). FESEM images demonstrate that the as-prepared products are uniform nanobelts with length of about 20 μm and width of 100–200 nm. EDS, XRD, and XPS spectroscopy show that Ce atoms were uniformly distributed in the crystal structure of MoO3 nanobelts. In comparison with pure samples, Ce-doped MoO3 nanobelts exhibited superior trimethylamine (TMA) sensing properties at a lower working temperature. The effects of Ce-doping on the trimethylamine sensing performance of MoO3 nanobelts were discussed based on the experimental results. In addition, this study provided insights and strategies for designing high performance TMA gas sensors.

Background Many studies have reported the impact of air pollution on cardiovascular disease (CVD), but few of these studies were conducted in severe haze-fog areas. The present study focuses on the impact of different air pollutant concentrations on daily CVD outpatient visits in a severe haze-fog city. Methods Data regarding daily air pollutants and outpatient visits for CVD in 2013 were collected, and the association between six pollutants and CVD outpatient visits was explored using the least squares mean (LSmeans) and logistic regression. Adjustments were made for days of the week, months, air temperature and relative humidity. Results The daily CVD outpatient visits for particulate matter (PM10 and PM2.5), sulphur dioxide (SO2), nitrogen dioxide (NO2), carbon monoxide (CO), and ozone (O3) in the 90th-quantile group were increased by 30.01, 29.42, 17.68, 14.98, 29.34%, and − 19.87%, respectively, compared to those in the 10 300- and 500-μg/m3, PM2.5 100- and 300-μg/m3 and CO 3-mg/m3 groups were 2.538 (1.070–6.020), 7.781 (1.681–36.024), 3.298 (1.559–6.976), 8.72 (1.523–49.934), and 5.808 (1.016–33.217), respectively, and their corresponding attributable risk percentages (AR%) were 60.6, 87.15, 69.68, 88.53 and 82.78%, respectively. The strongest associations for PM10, PM2.5 and CO were found only in lag 0 and lag 1. The ORs for the increase in CVD outpatient visits per increase in different units of the six pollutants were also analysed. Conclusions All five air pollutants except O3 were positively associated with the increase in daily CVD outpatient visits in lag 0. The high concentrations of PM10, PM2.5 and CO heightened not only the percentage but also the risk of increased daily CVD outpatient visits. PM10, PM2.5 and CO may be the main factors of CVD outpatient visits.

Along with the fast development of digital information technology and the application of Internet, video data begins to grow explosively. Some applications with high real-time requirements, such as object detection, require strong online video storage and analysis capabilities. Key-frame extraction is an important technique in video analysis, which provides an organizational framework for dealing with video content and reduces the amount of data required in video indexing. To address the problem, this study proposes a key-frame extraction method based on HSV (hue, saturation, value) histogram and adaptive clustering. The HSV histogram is used as color features for each frame, which reduces the amount of data. Furthermore, by using the transformed one-dimensional eigenvector, the fixed number of features can be extracted for images with different sizes. Then, a cluster validation technique, the silhouette coefficient, is employed to get the appropriate number of clusters without setting any clustering parameters. Finally, several algorithms are compared in the experiments. The density peak clustering algorithm (DPCA) model is shown to be more effective than the other four models in precision and F-measure.

The Doppler effect of motional polarization grating is studied for the first time to the best of our knowledge. Based on the optical properties of polarization grating, the Doppler effect principle of polarization grating is elucidated theoretically. A method to obtain the Doppler frequency shift based on beat frequency signal that is produced by superposition of order ± 1 diffraction beams of polarization grating is proposed, and a proof-of-concept experiment is conducted to measure the frequency signal of the motional polarization grating. The movement characteristics of polarization grating varying with time can be obtained after a short-time Fourier transformation of the light signal. The experimental results are in good agreement with the theoretical predication, which verifies the correctness of the theoretical analysis and achieves the measurement of linear motion velocity and acceleration of motional polarization grating with high accuracy. This study proposes a new idea for laser frequency shift and has potential significance for further development of optical heterodyne detection.

The magnetically suspended control and sense gyroscope (MSCSG) integrates spacecraft attitude measurement and control function; this paper proposes a double spherical rotor (DSR) for MSCSG. The DSR realizes the five degrees of freedom (DOFs) full active control and full channel magnetic path decoupling by the following design: the spherical axial/radial reluctance magnetic bearings are adopted to control the 3DOFs translation of rotor in the range of double spherical envelope, Lorentz force magnetic bearing (LFMB) is used to precisely drive the 2DOFs universal deflection of rotor. The optimization model is established based on the structural mechanical analysis, taking the deviation between rotor centroid and shape center as the optimization objective, choosing the first order resonance frequency, maximum equivalent stress, rigid body displacement, polar moment of inertia and inertia ratio as constraints. Then the DSR is optimized and simulated by the finite element, the MSCSG principle prototype based on DSR is successfully developed, the online dynamic balance experiment and modal test of the DSR are conducted, where the vibration amount of the DSR decreases from 20 μm before the experiment to 0.14 μm after the experiment, which decreases by 99.3%, the first test modal is 2881 Hz which is 5% different from the finite element simulation value of 3034 Hz. The results show that the DSR has the good mechanical properties and magnetic circuit decoupling characteristics.

In order to further study the influence of factors on the braking torque of liquid-cooled eddy current retarder (ECR) with dual salient poles, this paper applies electromagnetic theory to deduce the braking power and calculation formulas of braking torque considering the structural features of ECR with dual salient poles and also analyses the factors affecting the braking torque. On the basis of all above, this paper also makes detailed analyses about the influence of different stator materials and different thickness of plating layer on the braking torque. A 3-D model of ECR is built and JMAG software is used to carry out simulation analysis on the 3-D model. At last, the correctness of theoretical derivation and simulation analysis can be verified through prototype test, which provides a good theoretical guidance for the further optimization of ECR.

The paper aims to show the ability of the desired-dynamic-equations (DDE) based decentralized PID controller tuning method with its application to the ALSTOM gasifier benchmark control problem. The DDE-based PID controller tuning method was deduced from a kind of nonlinear adaptive controller with relative degree of two, which behaves good tracking performance and robustness by using an extended state observer and DDE to estimate and compensate the uncertainty and disturbance. The tunable parameters of DDE-based PID controller have explicit and distinctive physical meanings, thus can be tuned separately rather than iteratively as traditional PID controller does. The tuning method is firstly applied to the ALSTOM gasifier benchmark control problem with linear model, simulation shows that it exceeds output limits only twice (the least in literature) at 0% load with the step and sinusoidal disturbance; then the same controller is applied without any modification to nonlinear gasifier model, and the simulations show that it not only meets all control specifications, but also follows load change rapidly and shows good adaptability to the coal quality change.

Charging resources in the charging stations are limited. How to make electric vehicles get charging service with small cost is worth studying. The reserving charging model for electric vehicles is built based on the customer requirement model, considering the road condition of traffic system and available charging resources in the charging stations. All factors that influence the reserving charging are translated into weights and then being assigned to corresponding edges of traffic network graph. The Dijkstra algorithm is introduced to achieve the solution of the model built in this paper. Finally, a supposed traffic network is used to conduct a simulation, and the results show that the proposed optimization model of reserving charging for electric vehicles can satisfy users' different demands.

A 40-year-old man presented with a 3-year duration of intermittent upper abdominal pain. Gastroscopy and endoscopic ultrasonography revealed a tumor in the bottom of the stomach with a homogenous low echogenicity that originated from the gastric serosa. An abdominal contrast-enhanced computed tomography (CT) scan showed that a well-marginated ovoid mass was obviously enhanced homogenously in the arterial period and weakened slightly in the venous period. The diagnosis of a gastric stromal tumor was made. Laparoscopic resection of the gastric tumor was subsequently performed. Surprisingly, postoperative pathological examination of the mass showed the typical structure of a normal splenic tissue. To our knowledge, ectopic splenic tissue originating from the gastric serosa is reported for the first time, showing important clinical significance for the identification of gastric malignant tumors.

BACKGROUND The role of physical activity in preventing gallstone disease independent of its effect on the body weight has not been well established. We performed a systematic review and meta-analysis of cohort and case-control studies to analyze this potential association. METHODS We searched PubMed and EMBASE to identify all published studies in English through April 2016. We pooled the relative risks (RRs) or odds ratios (ORs) and corresponding 95% confidence intervals (CIs) from individual studies using a random-effects model to investigate associations between physical activity and the risk of gallstone disease. RESULTS A total of 16 studies comprising 19 independent reports of approximately 260,000 participants met the inclusion criteria, including 6 case-control studies and 13 cohort studies. In a pooled analysis of cohort studies, physical activity (in a comparison of the highest-level and the lowest-level groups) was associated with a reduced risk of gallstone disease (RR=0.85; 95% CI, 0.78-0.92; I=79.5%). For men, the RR was 0.76 (95% CI, 0.60-0.97), and for women, the RR was similar (RR=0.77; 95% CI, 0.66-0.91). In a dose-response analysis, the RR of gallstone disease was 0.87 (95% CI, 0.83-0.92; I=1.0%) per 20 metabolic equivalent-hours of recreational physical per week. In comparison, case-control studies yielded a stronger significant risk reduction for gallstone disease (OR=0.64; 95% CI, 0.46-0.90; I=76.6%). CONCLUSIONS This study suggests an inverse association between physical activity and gallstone disease in both men and women; however, these findings should be interpreted cautiously because of study heterogeneity.

A mathematical model with the flight string as the decision variables, aiming to minimize the number of the flights and to maximize the maintenance opportunities, is proposed in this paper, and a dynamically constructed flight string based ant colony algorithm is presented to solve the problem. A new mechanism of pheromone update is utilized in the algorithm to fasten the convergence rate. Numerical examples are extended from the small scale scheduling problems with single maintenance base to the large scale scheduling problems with multiple maintenance bases. Simulation results show that the proposed algorithm could not only solve the problem, but also improve the efficiency.

This paper presents several methods to maintain the stability of a new designed inspection robot when walking on the power transmission line and overcoming the obstacle on the line. The new dual-arm platform has 3 DOFs of each arm to fulfill rotating, lifting and lowering and moving on the line with a wheel. With a novel mechanism the robot can control the position of its center of gravity flexibly. The model of the power transmission line inspection robot is established for stability control. A FZMP controller is used to maintain the coincidence of the projection of the center of gravity and contact point, which is the necessary condition of the robot's stability. A look-ahead control algorithm is introduced to deal with the overshooting and vibration caused by sharp corner or high curvature in the joint space of the planned path to overcome an obstacle. The paper ends with the presentation of an experiment results.

The paper surveys and analyzes the basic present condition of Suiling black pottery in Heilongjiang Province, and innovates and designs black pottery products. This paper combines traditional technologies with modern design methods to enrich the categories of black pottery products, expands the industry chain, and promotes the economic development of Suiling. The rapid development of modern industry led to the decline of handicraft, and the development of Suiling black pottery has stagnated. Handicrafts should be designed and transformed to ensure the inheritance of traditional culture and skills.

Summary Background Epidemiologic evidence on coffee consumption reducing the risk of gallstone disease has been contradictory. Aim To perform a meta-analysis of observational studies, to investigate an association and dose–response of coffee consumption with gallstone disease. Methods We used PubMed and EMBASE databases to identify all published studies before June 2015. A random-effects model was used to compute a pooled relative risk (RR) and corresponding 95% confidence intervals (CIs). Results One case–control study and five prospective cohort studies (with seven cohorts) involving 227 749 participants and 11 477 gallstone disease cases were included. Coffee consumption was significantly associated with a reduced risk of gallstone disease (RR, 0.83; 95% CI, 0.76 to 0.89; I2 = 35.9%), based on prospective studies; specifically, we observed an inverse relation in females, but not in males. The case–control study did not reveal any association between coffee and gallstone disease (OR, 0.99; 95% CI, 0.64 to 1.53). In a dose–response analysis, the RR of gallstone disease was 0.95 (95% CI, 0.91 to 1.00; P = 0.049) per 1 cup/day of coffee consumption. A significant nonlinear dose–response association was also identified (P for nonlinearity = 0.0106). For people who drank 2, 4 and 6 cups of coffee per day, the estimated RRs of gallstone disease were 0.89 (95% CI, 0.79 to 0.99), 0.81 (95% CI, 0.72 to 0.92) and 0.75 (95% CI, 0.64 to 0.88), respectively, compared with the lowest level drinkers. Conclusion This study suggests that coffee consumption is related to a significantly decreased risk of gallstone disease.