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Background: In recent years, electrochemical sensors are widely preferred because of their high sensitivity, rapid response, low cost and easy miniaturization. Covalent organic frameworks (COFs), a porous crystalline polymer formed by organic units connected by covalent bonds, have been widely used in gas adsorption and separation, drug transportation, energy storage, photoelectric catalysis, electrochemistry and other aspects due to their large specific surface, excellent stability, high inherent porosity, good crystallinity as well as structural and functional controllability. The topological structure of COFs can be designed in advance, the structural units and linkage are diversified, and the structure is easy to be functionalized, which are all beneficial to their application in electrochemical sensors. Methods: The types, synthesis methods, properties of covalent organic frameworks and some examples of using covalent organic frameworks in electrochemical sensors are reviewed. Results: Due to their characteristics of a large specific surface, high porosity, orderly channel and periodically arranged π electron cloud, COFs are often used to immobilize metal nanoparticles, aptamers or other materials to achieve the purpose of building electrochemical sensors with high sensitivity and good stability. Since the structure of COFs can be predicted, different organic units can build COFs with different structures and properties. Therefore, organic units with certain functional groups can be selected to build COFs with certain properties and used directly for electrochemical sensors. Conclusion: COFs have a good application prospect in electrochemical sensors.

Mechanical precision corn seed-metering planter has a compact structure, missed and repeated seeding advantages during high-speed operation. In this regard, the current research study focuses on the development of a corn seed planter that features an inclined seed-metering device. The spatial layout of the seed-metering device is optimized to change the seed-filling mode to meet the needs of high-speed operation. Firstly, the mechanical characteristics and seeds in the metering device chamber were analyzed, and then the seed-filling stress model was established. Secondly, a mechanical model for corn seed particles was developed for virtual simulation tests and numerical analysis using the discrete element method (DEM) and EDEM software. Moreover, a quadratic rotating orthogonal center combination test was implemented by setting the inclination angle of seed-metering device θ(A), machine ground speed v(B), and rotation speed of metering disc n(C) as the influence factors, with the missed seeding rate M and the seed-filling stress S as the evaluation indices. The results indicated that the most significant factors affecting the missed seeding rate, seed-filling stress, S, were the rotation speed of the metering disc (n) > machine ground speed (v) > inclination angle of the metering disc (θ) and inclination angle of the metering device (θ) > rotation speed of the metering disc (n) > machine ground speed (v), respectively. However, the field verification test shows that the optimized corn seed-metering planter achieved mean values of M = 4.33, Q(qualified seeding rate) = 92.83%, and R(repeated seeding rate) = 2.84%, with average relative errors of 1.17% compared to the simulation tests and the accuracy and effectiveness of the DEM simulation model was verified. Therefore, the developed corn seed-metering device meets the industry standards and operation requirements for precise corn sowing, and technical support can be given for future studies of similar precision seeding equipment.

Studies have proven that the same family of non-coding RNAs (ncRNAs) have similar functions, so predicting the ncRNAs family is helpful to the research of ncRNAs functions. The existing calculation methods mainly fall into two categories: the first type is to predict ncRNAs family by learning the features of sequence or secondary structure, and the other type is to predict ncRNAs family by the alignment among homologs sequences. In the first type, some methods predict ncRNAs family by learning predicted secondary structure features. The inaccuracy of predicted secondary structure may cause the low accuracy of those methods. Different from that, ncRFP directly learning the features of ncRNA sequences to predict ncRNAs family. Although ncRFP simplifies the prediction process and improves the performance, there is room for improvement in ncRFP performance due to the incomplete features of its input data. In the secondary type, the homologous sequence alignment method can achieve the highest performance at present. However, due to the need for consensus secondary structure annotation of ncRNA sequences, and the helplessness for modeling pseudoknots, the use of the method is limited.In this paper, a novel method "ncDLRES", which according to learning the sequence features, is proposed to predict the family of ncRNAs based on Dynamic LSTM (Long Short-term Memory) and ResNet (Residual Neural Network).ncDLRES extracts the features of ncRNA sequences based on Dynamic LSTM and then classifies them by ResNet. Compared with the homologous sequence alignment method, ncDLRES reduces the data requirement and expands the application scope. By comparing with the first type of methods, the performance of ncDLRES is greatly improved.

We investigated the safety and efficacy of the Numen coil compared with the Axium coil in the treatment of intracranial aneurysms.Because CATCH (Coil Application Trial in China) is a prospective randomized controlled open-label noninferiority trial conducted in 10 centers across China, patients who fulfilled the inclusion and exclusion criteria were randomized 1:1 to either a test group (Numen) or a control group (Axium). The primary outcome was based on successful aneurysm occlusion at 6 months follow-up, whereas secondary outcomes included technical success, the recanalization and retreatment rates, and the rate of serious adverse events (SAEs) at 6 months and 12 months follow-up.Between August 2017 and December 2019, 350 patients presenting with 350 aneurysms were enrolled and randomized. Per-protocol analysis showed that the successful aneurysm occlusion rate at 6 months was 91.18% for the test group compared with 91.85% in the control group, with a difference of -0.68% (P = 0.8419), and the overall mortality during the 30-day follow-up period was 1.19% and 1.81% in the test and control group, respectively, showing no significant difference between the 2 groups (P = 0.6837), whereas the SAE incidence during the 12-month follow-up period was 12.50% and 17.47% in the test and control groups, respectively, which was not statistically significant (P = 0.2222).This trial showed that the Numen coil was noninferior to the Axium coil in terms of intracranial aneurysm embolization and can be considered as a safe and effective coil for treating patients with intracranial aneurysm in clinical practice.

A strategy has been applied to chloramphenicol (CAP) detection with chemiluminescence immunoassays (CLIA) based on cheap functionalized Fe3 O4 @SiO2 magnetic nanoparticles (Fe-MNPs). The strategy that bovine serum albumin (BSA) was immobilized on cheap functionalized Fe-MNPs and that the CAP molecules were then immobilized on BSA, avoided the long process of dialysis for preparation of the BSA-CAP conjugates. The samples were detected for both methods that utilized two different kinds of functionalized Fe-MNPs (amine-functionalized Fe3 O4 @SiO2 and carboxylic acid-functionalized Fe3 O4 @SiO2 ). The sensitivities and limits of detection (LODs) of the two methods were obtained and compared based on inhibition curves. The 50% inhibition concentrations (IC50 ) values of the two methods were about 0.024 ng ml-1 and 0.046 ng ml-1 respectively and LODs were approximately 0.0002 ng ml-1 and 0.001 ng ml-1 respectively. These methods were much more sensitive than that of any traditional enzyme-linked immunosorbent assay (ELISA) previously reported. Therefore, such chemiluminescence methods could be easily adapted for small molecule detection in a variety of foods using Fe-MNPs.

This study fully considers the incomparable factors in city's energy efficiency assessment, and proposes a framework for city's energy efficiency assessment based on classification. In the process of classifying cities, the SVM method is used to establish a quantitative relationship model between relevant factors and city's energy consumption. Based on the model, the objective energy demand of the city is calculated, and the city is classified according to the level of objective energy demand. By comparing the actual energy consumption of the city with the objective energy demand, we can eliminate the interference of the incomparable factors on the city's energy efficiency assessment.

Starts from the characteristics of the smart distribution and utilization system(SDUS), typical and representative applications are summarized for further research. The comprehensive benefit analysis model of SDUS from the perspective of the entire society, taking the battery-energy storage system (BESS), distributed generation (DG), charging and exchanging station, micro grid and smart home into account, is introduced on the basis of establishing the cost benefit models of all kinds of smart businesses through extracting the correlation among the various business from a bottom-up way. Combined with an example, the comprehensive benefit of SDUS and the contribution degrees of smart businesses to the benefits were analyzed. Result shows that the use of SDUS has certain social value, and the concept of net loss sensitivity and reliability sensitivity can be used to analysis redundant relationship and obtain the contribution degree of different devices to the total net loss benefit and total reliability benefit.

A strategy has been applied to chloramphenicol (CAP) detection with chemiluminescence immunoassays (CLIA) based on cheap functionalized Fe

A novel cost benefit analysis approach is proposed for the storage and distribution power and their combination when they are applied in smart distribution grid. The approach includes two parts, the cost-benefit analysis part and the operation simulation part. A life cycle cost analysis is addressed for the cost benefit analysis, which takes the working life of storages and distribution generations (PV in this case) into account. The operation simulation part takes charge in the simulation of the system, offers key parameters for the cost benefit analysis in real time based on the cost and the boundary conditions of the system. In such way, the bottom to up approach gives better understanding of the relation between cost and benefit. In particular, the comprehensive benefit of battery energy storage system (BESS) together with photovoltaic systems when applied in a given distribution grid is analysed, suggestions for the arrangement of the system are listed according to the simulation results.

Comparing to monostatic SAR, Bistatic SAR has specific advantages, such as the reduced vulnerability in military systems, additional information about the target and characteristics of signal. Nevertheless, it brings the complication of processing algorithms because of the range history of a Bistatic target is the sum of two hyperbolic range equations, which give a double square-root term in the range equation, and the traditional RD algorithms using in monostatic SAR can not apply for processing Bistatic SAR. This paper obtained the point target signal by establishing the echo signal model, then derived the approximate two-dimensional spectrum of echo signal by using POSP, and a Range Doppler Algorithm suitable for Bistatic SAR is presented. The algorithm is validated by the simulation experiments of point targets.

The technology of space-time signal processing can analyze the property of input signal in special and time-domain. Space-time configuration can greatly promote the freedom of the array antenna in order to raise the number of anti-jam without increasing the number of element of antenna. Especially, it improves capability of satellite receiver for suppressing broadband interferences. Paper puts forward a space-time least-mean-squares (STLMS) algorithm based on space-time signal processing. The algorithm can adaptively estimate the weighting vector of elements of antenna with a low computational complexity. The result of simulation demonstrates the STLMS algorithm can well reject the interferences and protect satellite signal.

In order to improve the complexity of chaotic signals, a new fractional-order four-dimensional hyperchaotic system is presented. Some dynamical properties of the system are investigated. The circuit implementation of this new system is simulated using Multisim. The results prove that chaos actually exists in the system with order as low as 3.2. A simple linear feedback controller is designed, and the simulation results are presented to demonstrate the effectiveness of the method.