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In this paper, a high selectivity wideband 180° phase shifter (PS) with the functionality of vertical transition is presented. The whole circuit is realized based on the hybrid microstrip/slotline (SL) structure. By introducing the short-circuited microstrip stepped-impedance resonators, two transmission zeros are created to improve the selectivity of the PS. With the SL in the center ground layer, a frequency independent 180° PS can be obtained. The even/odd-mode equivalent circuits of the proposed PS are analyzed to guide the design. Finally, a practical wideband 180° PS with high filtering selectivity is designed and fabricated to verify the design theory.
This paper presents a notched band ultra-wideband bandpass filter using a single perturbed quint-mode half-mode substrate-integrated waveguide cavity. The cavity is perturbed by loading four stubs at two corners of the magnetic walls of the single cavity. The variable parameters of stubs are selected to move down the first five resonant modes to the predetermined passband during the design process. Meanwhile, microstrip lines with a transition structure located on two loaded stubs are employed to feed the resonator. Moreover, the filter also firstly designs a notched band by introducing a complementary split-ring resonator inside the cavity to mitigate potential interference signals at 8 GHz (satellite communication). Finally, a prototype filter was implemented and measured to verify.
A four-way suspended-stripline power divider is presented in this letter. The power dividing network is designed by using the suspended stripline, while the isolation network is designed by using the microstrip line. The vias are used to connect the power dividing network and the isolation network. The even- and odd-mode analysis method is applied to design the presented power divider. The simulated and measured results of the presented power divider show reasonable agreement with each other. The measured input return loss in the band is greater than 28 dB (7.92 to 9.53 GHz), while the measured insertion loss is less than 0.37 dB. The measured output return loss is greater than 20 dB from 7.82 to 9.86 GHz. Besides, the measured output isolation is greater than 20 dB.
The cao vit gibbon Nomascus nasutus, also known as eastern black crested gibbon, is categorized as Critically Endangered on the IUCN Red List and was considered one of the world's 25 most threatened primates. The only known population occurs along the border between China and Viet Nam. Accurate information on population size and dynamics is critical for the species’ conservation, but population surveys conducted in only one country may over- or underestimate total population size because the home ranges of cao vit gibbon groups often cross the international border. In 2007 and 2016 we conducted two collaborative transboundary censuses of the cao vit gibbon populations in the Trung Khanh Cao Vit Gibbon Species and Habitat Conservation Area in Viet Nam and the Bangliang Gibbon National Nature Reserve in China. The results showed a population size of 102–110 in 2007, which increased to 107–136 in 2016. Our results indicate that previous surveys conducted separately in Viet Nam and China underestimated the global population size of this species. According to our more comprehensive surveys, the gibbon population is increasing slowly. The gibbons and their habitat are legally protected in both countries. Hunting and charcoal making have not been reported in this area since 2007. As habitat carrying capacity is a limiting factor, habitat restoration is required. However, lack of funding to protect the cao vit gibbon remains a challenge.
Schizophrenia is a complex mental disorder with high heritability and polygenic inheritance. Multimodal neuroimaging studies have also indicated that abnormalities of brain structure and function are a plausible neurobiological characterisation of schizophrenia. However, the polygenic effects of schizophrenia on these imaging endophenotypes have not yet been fully elucidated.
To investigate the effects of polygenic risk for schizophrenia on the brain grey matter volume and functional connectivity, which are disrupted in schizophrenia.
Genomic and neuroimaging data from a large sample of Han Chinese patients with schizophrenia (N = 509) and healthy controls (N = 502) were included in this study. We examined grey matter volume and functional connectivity via structural and functional magnetic resonance imaging, respectively. Using the data from a recent meta-analysis of a genome-wide association study that comprised a large number of Chinese people, we calculated a polygenic risk score (PGRS) for each participant.
The imaging genetic analysis revealed that the individual PGRS showed a significantly negative correlation with the hippocampal grey matter volume and hippocampus–medial prefrontal cortex functional connectivity, both of which were lower in the people with schizophrenia than in the controls. We also found that the observed neuroimaging measures showed weak but similar changes in unaffected first-degree relatives of patients with schizophrenia.
These findings suggested that genetically influenced brain grey matter volume and functional connectivity may provide important clues for understanding the pathological mechanisms of schizophrenia and for the early diagnosis of schizophrenia.
Robots often need to accomplish some complex tasks such as surveillance, response and obstacle avoidance. In this paper, a dynamic search method is proposed to generate optimal robot trajectories satisfying complex task requirement in uncertain environment. The LTL-A* algorithm is presented to generate a global optimal path and the A* algorithm is provided to modify the global optimal path. The task is specified by a linear temporal logic (LTL) formula, and a weighted transition system according to the known information in uncertain environment is modeled to describe the robot motion. Subsequently, a product automaton is constructed by combining the transition system with the task requirement. Based on the product automaton, the LTL-A* algorithm is proposed to generate a global optimal path. The local path planning based on the A* algorithm is employed to deal with the environment change during the process of tracking the global optimal path for the robot. The results of the simulation and experiments show that the proposed method can not only meet the complex task requirement in uncertain environment but also improve the search efficiency.
A compact wideband out-of-phase power divider (PD) with improved isolation performance is proposed. This divider is formed by connecting an additional stub for isolation to output ports of a traditional Marchand balun with a defected ground structure (DGS) been used. To verify the design, a prototype divider is fabricated and tested. The measured results validate the 53.86% band-width centered at 3.43 GHz with more than 15 dB return loss at all ports, more than 17 dB isolation, respectively.
To assess the effect of famine exposure during early life on dietary patterns, chronic diseases, and the interaction effect between famine exposure and dietary patterns on chronic diseases in adulthood.
Cross-sectional study. Dietary patterns were derived by factor analysis. Multivariate quantile regression and log-binomial regression were used to evaluate the impact of famine exposure on dietary patterns, chronic diseases and the interaction effect between famine exposure and dietary patterns on chronic diseases, respectively.
Adults aged 45–60 years (n 939).
‘Healthy’, ‘high-fat and high-salt’, ‘Western’ and ‘traditional Chinese’ dietary patterns were identified. Early-childhood and mid-childhood famine exposure were remarkably correlated with high intake of the traditional Chinese dietary pattern. Compared with the non-exposed group (prevalence ratio (PR); 95 % CI), early-childhood (3·13; 1·43, 6·84) and mid-childhood (2·37; 1·05, 5·36) exposed groups showed an increased PR for diabetes, and the early-childhood (2·07; 1·01, 4·25) exposed group showed an increased PR for hypercholesterolaemia. Additionally, relative to the combination of non-exposed group and low-dichotomous high-fat and high-salt dietary pattern, the combination of famine exposure in early life and high-dichotomous high-fat and high-salt dietary pattern in adulthood had higher PR for diabetes (4·95; 1·66, 9·05) and hypercholesterolaemia (3·71; 1·73, 7·60), and significant additive interactions were observed.
Having suffered the Chinese famine in childhood might affect an individual’s dietary habits and health status, and the joint effect between famine and harmful dietary pattern could have serious consequences on later-life health outcomes.
True ileal digestibility (TID) values of amino acid (AA) obtained using growing rats are often used for the characterisation of protein quality in different foods and acquisition of digestible indispensable amino acid scores (DIAAS) in adult humans. Here, we conducted an experiment to determine the TID values of AA obtained from nine cooked cereal grains (brown rice, polished rice, buckwheat, oats, proso millet, foxtail millet, tartary buckwheat, adlay and whole wheat) fed to growing Sprague–Dawley male rats. All rats were fed a standard basal diet for 7 d and then received each diet for 7 d. Ileal contents were collected from the terminal 20 cm of ileum. Among the TID values obtained, whole wheat had the highest values (P<0·05), and polished rice, proso millet and tartary buckwheat had relatively low values. The TID indispensable AA concentrations in whole wheat were greater than those of brown rice or polished rice (P<0·05), and polished rice was the lowest total TID concentrations among the other cereal grains. The DIAAS was 68 for buckwheat, 47 for tartary buckwheat, 43 for oats, 42 for brown rice, 37 for polished rice, 20 for whole wheat, 13 for adlay, 10 for foxtail millet and 7 for proso millet. In this study, the TID values of the nine cooked cereal grains commonly consumed in China were used for the creation of a DIAAS database and thus gained public health outcomes.
The ultra-wideband bandpass-response power divider with high-frequency selectivity is presented in this paper. This power divider consists of an impedance transformer, a filter network, and two isolation resistors. In order to realize the ultra-wideband filtering performance, parallel coupling lines and parallel open-circuit branches are applied to the second impedance converter. A resistor is added to the ends of the coupling lines to achieve good isolation and output return loss. The equivalent-circuit method is employed to analyze the presented power divider. The power divider, working at 3.45–8.29 GHz, is designed and fabricated. Two transmission zeros are generated at 2.8 and 9 GHz, respectively, and the out-of-band suppression is >13 dB. The measured results are in good agreement with the simulation ones.
A compact dual-wideband (DWB) bandpass filter utilizing open-shorted coupled lines (OSCL) is proposed in this paper. The introduction of the folded structure not only reduces the overall size but also contribute to the split of the transmission zero (TZ), which improves the selectivity effectively. Six transmission poles and five TZs are realized utilizing the shorted-circuit stub and OSCL. The characteristic of the flexible adjustment method of TZs guarantees an independently wide adjustable range of the bandwidth. For demonstration, a DWB filter (3 dB bandwidth 120 and 28%, respectively) is designed and fabricated. The filter is compact and has the characteristics of extraordinary wide bandwidth, low insertion loss, as well as high selectivity.
In this study, wideband bandpass power divider with good out-of-band performance is proposed. Two bandpass filters (BPFs) are utilized to substitute the quarter-wavelength transmission line in conventional Wilkinson power divider. A resistor is specially arranged between two BPFs for a good isolation. Four transmission zeros (TZs) are found to be distributed in the lower and upper stopband of the power divider. Moreover, the locations of two TZs can be shifted by tuning the impedance ratio of the center-loaded open stub, which is propitious to improve the frequency selectivity. Even- and odd-mode methods are applied to analyze the proposed power divider and closed-form design formulas are obtained. Finally, two prototype power dividers with measured rejection level in the upper stopband larger than 29.1 and 32 dB till to 2.7f0 and 2.69f0, respectively, are designed and fabricated to testify the proposed design concept. Good agreement between the simulated and measured results is observed, validating the validity of the proposed design principle.
A novel Gysel power divider with high power-handling capability based on half-mode substrate integrated waveguide (HMSIW) has been presented in this paper. A HMSIW ring is used and good input/output impedance matching is achieved based on HMSIW-microstrip taper transition. Two microstrip stubs are introduced in HMSIW ring to assemble two isolation resistors to improve the isolation between the output ports. The even- and odd-mode analysis method is used for the presented circuit. A prototype of the presented power divider is designed, fabricated, and measured. The measured results show a reasonable agreement with the simulated ones.
A miniaturized Bagley Polygon power divider based on composite right/left-handed transmission line is presented. The composite right/left-handed transmission line and conventional microstrip transmission line are utilized to realize the 0° phase shift transmission line, which is used to replace the 180° transmission line of the conventional Bagley Polygon power divider. As a result, miniaturization is realized, without deteriorating the isolation between the output ports. The design equations are presented. This power divider shows advantages compared with other miniaturized ones. For verification, a miniaturized Bagley Polygon power divider is designed and fabricated. The 58.2% length reduction of the counterpart is realized. The measurement and simulation results show good agreement.
A miniaturized tri-passband power divider integrating a power divider with two tri-band bandpass filters is presented. The short- and open-stub-loaded resonators are used in this presented power divider to implement the bandpass-filtering response. Then, the presented power divider has not only the power-dividing/combining function, but also the tri-passband filtering response. When the central frequency of the second passband is fixed, the other two passband central frequencies of the tri-band power divider can be flexibly controlled by changing the lengths of the stubs. The even- and odd-mode equivalent circuits of the proposed tri-band power divider are analyzed, and the design equations are derived, which can be used to guide the design of the presented miniaturized tri-passband power divider. The measured results agree well with the simulated ones.
A compact multi-layer N-way power-dividing structure with good isolation and output return loss performance is proposed. The isolation network is circularly distributed that constitutes a closed ring-shaped architecture. The equivalent circuit model is given and the [S] matrix is developed to analyse and design the power-dividing structure. Finally, a six-way power divider centered at 2.1 GHz is designed and fabricated. The measured and simulated results agree well with each other. The total size of the power divider is 0.13λg × 0.19λg.
A wide-stopband bandpass-filtering power divider with high-frequency selectivity has been proposed in this paper. The input and output feeding lines and eight 1/4 wavelength resonators are used to realize the signal transmission. In order to obtain good frequency selectivity, source-load coupling transmission path is used to generate transmission zeros near the passband. A four-way power divider with bandpass-filtering response and high-frequency selectivity is designed, fabricated, and measured. The measured results agree with the simulated ones closely in the desirable frequency range. The measured center frequency of the power divider is 2.38 GHz with input return loss of 31.2 dB, while the measured insertion loss is about 1 dB (not including ideal 6 dB four-way power dividing insertion loss). Moreover, the measured 3-dB bandwidth is 12% and the measured stopband attenuation is >15 dB from 2.59 to 7.7 GHz. In addition, two transmission zeros of 1.9 and 2.8 GHz are located near the passband. The measured output isolations are all >15.7 dB.
This article outlines the evolution of a rescue team in responding to adenovirus prevention with a deployable field hospital. The local governments mobilized a shelter hospital and a rescue team consisting of 59 members to assist with rescue and response efforts after an epidemic outbreak of adenovirus. We describe and evaluate the challenges of preparing for deployment, field hospital maintenance, treatment mode, and primary treatment methods. The field hospital established at the rescue scene consisted of a medical command vehicle, a computed tomography shelter, an X-ray shelter, a special laboratory shelter, an oxygen and electricity supply vehicle, and epidemic prevention and protection equipment. The rescue team comprised paramedics, physicians, X-ray technicians, respiratory therapists, and logistical personnel. In 22 days, more than 3000 patients with suspected adenovirus infection underwent initial examinations. All patients were properly treated, and no deaths occurred. After emergency measures were implemented, the spread of adenovirus was eventually controlled. An emergency involving infectious diseases in less-developed regions demands the rapid development of a field facility with specialized medical personnel when local hospital facilities are either unavailable or unusable. An appropriate and detailed prearranged action plan is important for infectious diseases prevention. (Disaster Med Public Health Preparedness. 2018;12:109–114)
A novel miniaturized dual-mode bandpass filter (BPF) using hexagonal loop resonator is presented. In order to reduce the circuit size, capacitive loading structure is applied to enhance the self-capacitance and electrical length of the hexagonal loop resonator. The frequency selectivity and out-of-band rejection of the proposed BPF can be improved by the two inherent transmission zeros in each side of the passband. Compared with the conventional hexagonal loop resonator without capacitive loading structure, the size of the proposed resonator is reduced by 46.6%. The simulated and measured results are presented and show good agreement.
In this paper, a 2.45-GHz wideband harmonic rejection rectenna for wireless power transfer is proposed. The rectenna comprises a microstrip-fed circular ring slot antenna (CRSA) and a series-parallel rectifier (SPR). A compact micro strip resonant cell is inserted into the CRSA so that the harmonic suppression over a wide bandwidth (3–8 GHz) can be obtained. The radio-frequency (RF)–DC conversion efficiency of the SPR is improved effectively by loading a proper compensating inductance, especially under the low input power levels. Furthermore, the proposed rectenna can easily achieve large-scale rectenna arrays using its simple structure. The adopted rectenna fabricated on a low cost Taconic RF-35 substrate has been measured. By up to 3rd-order harmonic rejection, the efficiency of the rectenna can achieve 70.2% with the optimum load resistance 1 kΩ. Good agreement among the calculated, simulated, and measured rectenna is observed.