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Rational regulation of local environment of Ti-sites in TS-1 harbours tremendous industrial and scientific significance to epoxidation reactions. Herein, we report a facile and environment-friendly strategy to boost catalytic selectivity by covering the Ti-sites on external surface of TS-1 (ITS-1) without sacrificing activity of internal Ti sites. By quantitative analysis of d3-acetonitrile and quinoline-DRIFTS, 1H MAS NMR and XPS, it is found that percentage of external Ti-sites decreased from 11% to 6% after depositing surface silica islands. This successfully inhibits ring-opening reaction of 1,2-epoxyhexane on catalyst surface, as demonstrated by slower kinetic decomposition rate of 1,2-epoxyhexane. Compared with conventional TS-1 catalyst, selectivity of 1,2-epoxyhexane over ITS-1 catalyst significantly increased from 83.5% to 98.5% while maintaining high 1-hexene conversion. Furthermore, overmuch surface silica coverage only leads to extremely low conversion (2%) due to inhibition of mass transfer. This work paves the way for rational construction of Ti-containing catalysts for 1-hexene epoxidation

With the rapid development of electronic devices, it is urgent to design and fabricate lightweight and effective electromagnetic absorption materials. Here, the graphene nanosheets/carbon nanotube/poly(vinylidene fluoride) (GNS/CNT/PVDF) composites with three-dimensional interconnected hierarchically porous networks have been successfully prepared via a facile solution mixing and followed by phase inversion method. The specific hierarchically porous structure in the composites possesses interconnected pores with various sizes. The open micro-scale pores on the top side give much smaller permittivity, which makes it less resistive to the incident microwave in a wide frequency range and is advantageous for multiple reflection and scattering of electromagnetic waves (EMW). The relatively smooth and dense bottom prevents EMW passing through the composites, which endows the prepared composites with a high EMW absorption. The as-prepared porous composites with 3.5 mm thickness exhibit a maximum absorption value of as high as − 32.7 dB at 11.50 GHz and display an ultra-wide efficient absorption bandwidth (entire X-band). Therefore, our work sheds light on a feasible strategy for designing and fabricating high-efficient EMW absorption materials.

A facile strategy combining ultrasonication and high-efficient hot-pressing technique is proposed to largely fabricate a thinner conductive composite film with excellent electromagnetic interference (EMI) shielding performance by employing graphene nanosheets to decorate porous cellulose aerogels (CA). Morphology examination reveals that a three-dimensional sheet-like skeleton network with highly oriented layered structure along the plane direction is perfectly constructed in the prepared CA composite film, which endows the prepared composite film with a high electrical conductivity of 91.2 S/m, excellent EMI shielding effectiveness (SE) of 49.5 dB and impressive normalized surface specific SE of 1509.6 dB·cm2/g at a thickness of only 0.6 mm. Also, the obtained composite film achieves good mechanical fastness and chemical durability, including the excellent resistance to ultrasonic treatment (60 min), tape adhesion (1000 cycles), and pH tolerant tests (pH = 2.0/12.0 for 24 h). This work provides a feasible and novel strategy for fabricating high-efficient EMI shielding performance composite film that suitable for high precision and sensitive electronic instruments even under harsh environment.

Manufacturing dielectric/magnetic composites with hierarchical structure is regard as a promising strategy for the progress of high-performance microwave absorption (MA) materials. In this paper, the nano-grass structured CoNiO

The development of electromagnetic interference (EMI) shielding materials with excellent absorption coefficient (A) is vital to completely eliminate the pollution of the ever-increasing electromagnetic waves (EMWs). In this regard, a TiC/carbon hybrid aerogel, derived from MXene/cellulose aerogel, was successfully fabricated via freeze-drying and subsequent pyrolysis process. Profiting from the open, loose three-dimensional (3D) macro pores with sheet-like morphology and high porosity, as well as the rich heterogeneous interfaces between TiC and cellulose-derived carbon, the as-prepared hybrid carbon aerogel achieves ultra-efficient EMI shielding effectiveness of 72.9 dB in conjunction with a superior A value of 0.76 and low thermal conductivity. These properties endow the as-prepared aerogel with strong absorption-dominant ultra-efficient EMI shielding and thermal insulation performance to meet the complex practical requirements. This work provides a promising strategy for achieving ultra-efficient multifunctional EMI shielding performance and superior A simultaneously.

In this study, Zr active species were implanted into a ZSM-5 zeolite framework to form a solid acid catalyst through steam treatment and the liquid-solid isomorphous substitution process. The as-synthesized Zr-ZSM-5-st catalyst ensured excellent esterification of trimethylolpropane and fatty acids (FAs) to achieve a polyol ester production yield of 94.41%. Combined with N2 physisorption, X-ray diffraction, Fourier transform infrared spectroscopy, ultraviolet-visible spectroscopy, transmission electron microscopy mapping, X-ray photoelectron spectroscopy, NH3 temperature-programmed desorption, and inductively coupled mass plasma spectroscopy were conducted. The results revealed that the excellent performance of Zr-ZSM-5-st catalyst could be attributed to the enhanced acidity and the developed surface area and pore structure.

Flexible strain sensors have attracted intense interest due to their application as intelligent wearable electronic devices. However, it is still a huge challenge to achieve a flexible sensor with simultaneous high sensitivity, excellent durability, and a wide sensing region. In this work, a crack-based strain sensor with a paired-serpentine conductive network is fabricated onto flexible film by screen printing. The innovative conductive network exhibits a controlled crack morphology during stretching, which endows the prepared sensor with outstanding sensing characteristics, including high sensitivity (gauge factor up to 2391.5), wide detection (rang up to 132%), low strain detection limit, a fast response time (about 40 ms), as well as excellent durability (more than 2000 stretching/releasing cycles). Benefiting from these excellent performances, full-range human body motions including subtle physiological signals and large motions are accurately detected by the prepared sensor. Furthermore, wearable electronic equipment integrated with a wireless transmitter and the prepared strain sensor shows great potential for remote motion monitoring and intelligent mobile diagnosis for humans. This work provides an effective strategy for the fabrication of novel strain sensors with highly comprehensive performance.

Background: This study will assess the efficacy and safety of ventilator for the management of severe pneumonia (SP). Methods: This study will search the following electronic databases in MEDLINE, EMBASE, Web of Science, PsycINFO, Cochrane Library, CNKI, and Scopus from the beginning to present without language restrictions. Two authors will screen all records according to the eligibility criteria; assess study quality; and extract all essential data from eligible studies. If sufficient studies are included, we will pool the extracted data and carry out meta-analysis. Results: This study will summarize published studies to assess the efficacy and safety of ventilator for patients with SP. Conclusion: The results of this study may supply a genuine understanding of perspective from a scientific basis on ventilator for the management of patients with SP.

Using natural non-polluting raw materials to develop absorption-based electromagnetic interference shielding composites is significantly desirable. Herein, a novel kind of carbonized loofah@graphene nanosheets (GNSs)-carbon nanotubes (CNTs)/epoxy resin modified cyanate ester (CL@GC/CE) composites were successfully prepared through high-temperature carbonization and variable temperature curing process, which show the absorption-based electromagnetic interference (EMI) shielding performance. The as-prepared composites present a favorable electrical conductivity of 32.66 S/cm, exceptional EMI shielding efficiency of 35.57 dB in conjunction with a high absorption coefficient of 0.58. The main reasons for the excellent absorption capacity and EMI shielding performance of the CL@GC/CE composites are the good impedance matching performance of carbonized loofah sponge with a 3D conductive framework, and the multiple reflection scattering and interface polarization effect between the conductive framework and GNSs-CNTs. In view of the remarkable comprehensive properties, the low-cost biomass-derived carbon composites are highly promising materials for practical EMI shielding applications in the fields of telecommunication and aerospace.

The whitefly, Bemisia tabaci, has developed a high level of resistance to thiamethoxam, a second generation neonicotinoid insecticide that has been widely used to control this pest. In this study, we assessed the level of cross-resistance, the activities of detoxifying enzymes, and the expression profiles of 23 glutathione S-transferase (GST) genes in a thiamethoxam-resistant ant and -susceptible strain of Bemisia tabaci Q. The thiamethoxam-resistant strain showed a moderate level of cross-resistance to another nicotinoid insecticide imidacloprid, a low level of cross-resistance to acetamiprid and nitenpyram, and no significant cross-resistance to abamectin and bifenthrin. Among detoxifying enzymes, only GSTs had significantly higher activity in the resistant strain than in the susceptible strain. Seven of 23 GST genes were over-expressed in the resistant strain relative to the susceptible strain. Using the technology of RNA interference to knockdown a GST gene (GST14), the results showed that silencing GST14 increased the mortality of whiteflies to thiamethoxam in Bemisia tabaci.

Background This study will assess the efficacy and safety of arthroscopic capsular release (ACR) for the treatment of post-stroke frozen shoulder (PSFS). Methods We will carry out a systematic study of randomized controlled trials that assess the efficacy and safety of ACR for PSFS. We will search all potential records for any eligible trials from selected electronic databases (MEDLINE, EMBASE, Cochrane Library, Web of Science, Chinese Biomedical Literature Database, WANGFANG, and China National Knowledge Infrastructure) and grey literature sources from inception to the present. Two authors will independently perform study selection, data extraction, and study quality assessment. Any disagreement will be solved by a third author via consultation. Statistical analysis will be carried out by RevMan 5.3 software. Results This study will comprehensively summarize current eligible studies to systematically assess the efficacy and safety of ACR for PSFS. Conclusion This study will provide evidence to determine whether ACR is an effective management for patients with PSFS.

BACKGROUND This study will investigate the efficacy and safety of shoulder arthroscopic surgery (SAS) for patients with rotator cuff injury (RCI). METHODS We will systematically search for randomized controlled trials in the electronic databases of PUBMED, EMBASE, Cochrane Library, CINAHL, PsycINFO, Web of Science, Allied and Complementary Medicine Database, Chinese Biomedical Literature Database, and China National Knowledge Infrastructure. All above databases will be searched from their beginning to March 1, 2020 without language restrictions. Two reviewers will independently scan retrieved records, evaluate study quality and extract data. If possible, we will synthesize the data and conduct a meta-analysis by RevMan 5.3 software. RESULTS This systematic review will summarize the most recent evidence to explore the efficacy and safety of SAS for patients with RCI. CONCLUSION The findings of this study will help to provide a genuine understanding of perspective from a scientific basis on the efficacy and safety of SAS for patients with RCI. PROSPERO REGISTRATION NUMBER PROSPERO CRD42020170009.

To realize quick localization of plant maize, a new real-time localization approach is proposed for maize cores at the seedling stage, which can meet the basic demands for localization and quantitative fertilization in precision agriculture and reduce environmental pollution and the use of chemical fertilizers. In the first stage, by taking pictures of maize at the seedling stage in a field with a monocular camera, the maize is segmented from the weed background of the picture. And then the three most-effective methods (i.e., minimum cross entropy, ISODATA, and the Otsu algorithm) are found from six common segmentation algorithms after comparing the accuracy rate of extracting maize and the time efficiency of segmentation. In the second stage, plant core from segmented maize image is recognized, and localized, based on different brightness of the rest part of maize core and plant. Then the geometric center of maize core is considered as localization point. the best effect of extracting maize core was found from the minimum cross entropy method based on gray level. According to experimental validation using many field pictures, under weedy conditions on sunny days, the proposed method has a minimum recognition rate of 88.37% for maize cores and is more robust at excluding weeds.

As the basis of plant canopy chlorophyll fluorescence kinetics, light distribution within the canopy determines the interaction relationship between plant physical processes and ecological environment. Spectroscopy technology plays a very important role in building a prediction model of component content to plant canopies. However, there is only limited number of reports about chlorophyll fluorescence properties of different light intensity areas to free spindle apple canopies. In this paper, with the free spindle apple tree as the research object, the canopy space of apple tree was divided into five layers, and six cube grids with 50cm length of side in each layer, and then the light distribution was determined through measuring the light intensity of each cube grids space. firstly, spectrum data and characters of chlorophyll fluorescence were obtained in the different light area; secondly, a differential spectrum curve in red area(680~760 nm) was determined through removing the interference of system error by a differential spectrum; thirdly, relationship model has been established innovatively between the maximum value in red area(680~760 nm) and the chlorophyll fluorescence characters, which has been used as calculation method of chlorophyll fluorescence characters in different light area to apple tree canopy. Fourthly, root mean square error, mean absolute percentage error, mean forecast error were adopted to evaluate the method. The test result shows that the accuracy of the method is all above 80%, which can be the theoretical basis for pruning and getting best light distribution to apple tree canopy.

Bemisia tabaci has developed a high level of resistance to thiamethoxam, a second generation neonicotinoid insecticide that has been widely used to control this pest. In this study, we investigated whether hydroxyacid-oxoacid transhydrogenase (HOT) is involved in resistance to the neonicotinoid insecticide thiamethoxam in the whitefly. We cloned the full-length gene that encodes HOT in B. tabaci. Its cDNA contains a 1428-bp open reading frame encoding 475 amino acid residues. Then we evaluated the mRNA expression level of HOT in different developmental stages, and found HOT expression was significantly greater in thiamethoxam resistance adults than in thiamethoxam susceptible adults. Subsequently, seven field populations of B. tabaci adults were sampled, the expression of mRNA level of HOT significant positive correlated with thiamethoxam resistance level. At last, we used a modified gene silencing system to knock-down HOT expression in B. tabaci adults. The results showed that the HOT mRNA levels decreased by 57% and thiamethoxam resistance decreased significantly after 2 days of feeding on a diet containing HOT dsRNA. The results indicated that down-regulation of HOT expression decreases thiamethoxam resistance in B. tabaci adults.

This paper collects the Internet data of 2013 related with Internet finance from several websites,and identifies key words by ICTCLAS,then analyses the co-word network by Bicomb based on key words co-occurrence.By the help of factor and cluster analysis, it studies the relationship between the key words then tracks the hot spots of Internet finace on the Internet.The analysis shows mobile payment,supervision,risk control and P2P network loan are focused in Internet finance field,Mobile payment,supervision,risk management become the hotspots at present.

Rongxi Zhou, Xiuguo Wang, Xuefan Dong, Ze Zong 1, first School of Economics and Management, Beijing University of Chemical Technology, Beijing 100029, China, zhourx@buct.edu.cn 2 School of Banking and Finance, University of New South Wales, Sydney, NSW 2052, Australia, zhourx@buct.edu.cn School of Applied Mathematics, Central University of Finance and Economics, Beijing 100081, China 4, Corresponding Author School of Business, University of Nottingham Ningbo China, Ningbo 315100, China 5, School of Economics and Management, Beijing University of Chemical Technology, Beijing 100029, China

In this paper, a novel non-uniform rational B-spline (NURBS) interpolator is proposed and implemented. This interpolator considers chord errors, feedrate fluctuations and acceleration/deceleration capabilities of the machine. And by introducing the improved S curve Acc/Dec feedrate control algorithm, recursive look-ahead algorithm and dual-port queue, it ensures a high machining accuracy and real-time performance. The advantages of the algorithm were confirmed by the simulation and analyses.

This paper presents a review for Distributed Mobility Management (DMM). Mobility Management is one of the key technologies in Mobile Network. DMM can solve the problems of traditional Centralized Mobility Management (CMM) such as non-optimal route and single point of failure and attack. There are several DMM approaches in recent researches. Some are based on MIP and some on PMIP. We summarize and present an optional optimization (O2) strategy in this paper.

Grating measurement techniques have revolutionized many fields of science and engineering and become more widely used than ever, a good generalized optical law of diffraction energy distribution and fringes patterns will make its performance better in high precision control and metrology. Here, we focus on the diffraction field of optical system which mainly composed of two identical sinusoidal amplitude gratings with dynamic rotation between them. We derive the light intensity on reception screen when the laser beam passing through the double-grating system by using Fourier optics theory. Simulation of diffraction field at different relative positions of two gratings show waveform changes of intensity along any linear direction in the screen plane, demonstrate continuous monotonic relationship between rotation angle θ and fringe spacing.

Background North central China has some of the highest rates of esophageal squamous cell carcinoma in the world with cumulative mortality surpassing 20%. Mitochondrial DNA (mtDNA) accumulates more mutations than nuclear DNA and because of its high abundance has been proposed as a early detection device for subjects with cancer at various sites. We wished to examine the prevalence of mtDNA mutation and polymorphism in subjects from this high risk area of China. Methods We used DNA samples isolated from tumors, adjacent normal esophageal tissue, and blood from 21 esophageal squamous cell carcinoma cases and DNA isolated from blood from 23 healthy persons. We completely sequenced the control region (D-Loop) from each of these samples and used a PCR assay to assess the presence of the 4977 bp common deletion. Results Direct DNA sequencing revealed that 7/21 (33%, 95% CI = 17–55%) tumor samples had mutations in the control region, with clustering evident in the hyper-variable segment 1 (HSV1) and the homopolymeric stretch surrounding position 309. The number of mutations per subject ranged from 1 to 16 and there were a number of instances of heteroplasmy. We detected the 4977 bp 'common deletion' in 92% of the tumor and adjacent normal esophageal tissue samples examined, whereas no evidence of the common deletion was found in corresponding peripheral blood samples. Conclusions Control region mutations were insufficiently common to warrant attempts to develop mtDNA mutation screening as a clinical test for ESCC. The common deletion was highly prevalent in the esophageal tissue of cancer cases but absent from peripheral blood. The potential utility of the common deletion in an early detection system will be pursued in further studies.

Commission 41 has been involved in one colloquium and one symposium since the last report: IAU Colloquium 91 on “The History of Oriental Astronomy” was held in New Delhi, November 13–16, 1985, preceding the XlXth General Assembly. Members of the scientific organizing committee were S.M.R. Ansari, E.S. Kennedy, D. King, R. Mercier, O. Pedersen, D. Pingree, G. Saliba, Xi Ze-Zong and K. Yabuuti. The colloquium was co-sponsored by the International Union for the History and Philosophy of Science, and by a number of organizations in India: the Council of Scientific and Industrial Research, New Delhi, the Department of Science and Technology, New Delhi, the Indian Institute of Astrophysics, Bangalore, the Indian National Science Academy, New Delhi, the Tata Institute of Fundamental Research, Bombay, and the University Grants Commission, New Delhi. The local organizing committee, chaired by G. Swarup, made possible a number of local excursions, including a conducted tour of the great stone open air observatory, built in the city by the enlightened Maharadjah Jai Singh in the 18th century. The colloquium brought 84 participants from 19 countries. 46 papers were presented of which 10 were invited, covering aspects of astronomy in the far east and middle east since the earliest civilizations. Papers from Colloquium 91 have now been published in book form: History of Oriental Astronomy, G. Swarup, A.K. Bag, and K.S. Shukla, editors, Cambridge University Press, Cambridge, England, 1987. Contributions are divided into three broad categories: ancient astronomy and its characteristics, ancient elements and planetary models, and medieval astronomy. Within these are papers on the characteristics and achievements of early astronomy in the eastern half of the world, including inter-regional development and mutual influences, ancient data relating to eclipses, supernovae and comets, medieval astronomical developments, instruments and early observatories, and the interplay between observational and theoretical astronomy. A short introductory paper by the revered historian E.S. Kennedy opens the book, as it set the stage for the colloquium in New Delhi: “We find (astronomy) originating a few centuries before the Christian era in two disparate cultures, Mesopotamia and the Hellenistic world. From the Mediterranean it passed to India, there to flourish. Thence the centroid of activity moved westward, residing in the lands of Islam during medieval times, more recently in Europe. Now astronomical research is carried out throughout the entire world.”

Commission 41 has been involved in one colloquium and one symposium since the last report:IAU Colloquium 91 on “The History of Oriental Astronomy” was held in New Delhi, November 13-16, 1985, preceding the XlXth General Assembly. Members of the scientific organizing committee were S.M.R. Ansari, E.S. Kennedy, D. King, R. Mercier, O. Pedersen, D. Pingree, G. Saliba, Xi Ze-Zong and K. Yabuuti. The colloquium was co-sponsored by the International Union for the History and Philosophy of Science, and by a number of organizations in India: the Council of Scientific and Industrial Research, New Delhi, the Department of Science and Technology, New Delhi, the Indian Institute of Astrophysics, Bangalore, the Indian National Science Academy, New Delhi, the Tata Institute of Fundamental Research, Bombay, and the University Grants Commission, New Delhi. The local organizing committee, chaired by G. Swarup, made possible a number of local excursions, including a conducted tour of the great stone open air observatory, built in the city by the enlightened Maharadjah Jai Singh in the 18th century. The colloquium brought 84 participants from 19 countries. 46 papers were presented of which 10 were invited, covering aspects of astronomy in the far east and middle east since the earliest civilizations. Papers from Colloquium 91 have now been published in book form: History of Oriental Astronomy, G. Swarup, A.K. Bag, and K.S. Shukla, editors, Cambridge University Press, Cambridge, England, 1987. Contributions are divided into three broad categories: ancient astronomy and its characteristics, ancient elements and planetary models, and medieval astronomy. Within these are papers on the characteristics and achievements of early astronomy in the eastern half of the world, including inter-regional development and mutual influences, ancient data relating to eclipses, supernovae and comets, medieval astronomical developments, instruments and early observatories, and the interplay between observational and theoretical astronomy. A short introductory paper by the revered historian E.S. Kennedy opens the book, as it set the stage for the colloquium in New Delhi: “We find (astronomy) originating a few centuries before the Christian era in two disparate cultures, Mesopotamia and the Hellenistic world. From the Mediterranean it passed to India, there to flourish. Thence the centroid of activity moved westward, residing in the lands of Islam during medieval times, more recently in Europe. Now astronomical research is carried out throughout the entire world.”