Analysis on characteristics of extreme precipitation indices and atmospheric circulation in Northern Shanxi

This article utilizes daily precipitation data from 28 national meteorological stations in northern Shanxi Province spanning from 1972 to 2020,and the US NCEP/NCAR monthly average reanalysis and ERA5 monthly average reanalysis data.The study employs techniques such as empirical orthogonal function(EOF)decomposition,MannKendall mutation and other methods to investigate the spatiotemporal distribution of extreme precipitation index in northern Shanxi and their correlation with atmospheric circulation.The research results show that:the absolute index,relative index,intensity index and sustained dry period index(CDD)in the continuous index appear from southwest to northeast.The spatial distribution characteristics of the central region decrease,while the continuous wet period(CWD)decreases from the central to the east and west.The three indices Rx1day,Rx5day,and CWD mutated in 1978,1975,and 1983 respectively,and other extreme precipitation indices all appeared in a sudden change from a low-value period to a high-value period occurred around 2010.In the high-value years of the summer extreme precipitation index,there is a significant negative anomaly in the height field in the mid-high latitude regions of Eurasia.Northern Shanxi is controlled by a broad low-pressure trough in the Lake Baikal area.Water vapor transported via the east,west,and south routes converges in the northern Shanxi region and encounters cold air from the north.There is a strong upward motion anomaly at 500 hPa in the troposphere,and the dynamic conditions of upper-level divergence and lower-level convergence lead to more summer extreme precipitation in the northern Shanxi region.Conversely,in the low-value years of the summer extreme precipitation index,northern Shanxi is affected by a strong high-pressure ridge north of Lake Baikal.There is a downward motion anomaly at 500 hPa,and the northern Shanxi region lacks water vapor.The cold and warm air cannot converge,and both the water vapor conditions and dynamic conditions are poor,which is not conducive to the production of extreme precipitation in northern Shanxi.

Nonreciprocal Photon Blockade Based on Zeeman Splittings Induced by a Fictitious Magnetic Field

Quantum nonreciprocity, such as nonreciprocal photon blockade, has attracted a great deal of attention due to its unique applications in quantum information processing. Its implementation primarily relies on rotating nonlinear systems, based on the Sagnac effect. Here, we propose an all-optical approach to achieve nonreciprocal photon blockade in an on-chip microring resonator coupled to a V-type Rb atom, which arises from the Zeeman splittings of the atomic hyperfine sublevels induced by the fictitious magnetic field of a circularly polarized control laser. The system manifests single-photon blockade or multi-photon tunneling when driven from opposite directions. This nonreciprocity results from the directional detunings between the countercirculating probe fields and the V-type atom, which does not require the mechanical rotation and facilitates integration. Our work opens up a new route to achieve on-chip integrable quantum nonreciprocity, enabling applications in chiral quantum technologies.

Acellular ostrich corneal stroma used as scaffold for construction of tissue-engineered cornea

AIM： To assess acellular ostrich corneal matrix used as a scaffold to reconstruct a damaged cornea. METHODS： A hypertonic saline solution combined with a digestion method was used to decellularize the ostrich cornea. The microstructure of the acellular corneal matrix was observed by transmission electron microscopy （TEM） and hematoxylin and eosin （H＆E） staining. The mechanical properties were detected by a rheometer and a tension machine. The acellular corneal matrix was also transplanted into a rabbit cornea and cytokeratin 3 was used to check the immune phenotype, RESULTS： The microstructure and mechanical properties of the ostrich cornea were well preserved after the decellularization process, in vitro, the methyl thiazolyl tetrazoUum results revealed that extracts of the acellular ostrich corneas （AOCs） had no inhibitory effects on the proliferation of the corneal epithelial or endothelial cells or on the keratocytes, The rabbit lamellar keratoplasty showed that the transplanted AOCs were transparent and completely incorporated into the host cornea while corneal turbidity and graft dissolution occurred in the acellular porcine cornea （APC） transplantation, The phenotype of the reconstructed cornea was similar to a normal rabbit cornea with a high expression of cytokeratin 3 in the superficial epithelial cell layer, CONCLUSION： We first used AOCs as scaffolds to reconstruct damaged corneas. Compared with porcine corneas, the anatomical structures of ostrich corneas are closer to those of human corneas. In accordance with the principle that structure determines function, a xenograft lamellar keratoplasty also confirmed that the AOC transplantation generated a superior outcome compared to that of the APC graft.

Influence of a low-frequency alternating magnetic field on hot tearing susceptibility of EV31 magnesium alloy

The effect of a low-frequency alternating magnetic field (AMF,0 A 0 Hz,5 A 10 Hz,10 A 10 Hz,15 A 10 Hz) on the hot tearing susceptibility (HTS) of a magnesium alloy (EV31) was systematically studied using a combination of experiment and numerical simulation.By observing the macroscopic hot cracks in hot joints of the "T" samples,the hot tearing tendency of the samples was analyzed.The HTS of the alloy can be predicted via numerical simulation and the crack susceptibility coefficient (CSC).The microstructure and morphology of the hot tearing zone of EV31 were investigated using scanning electron microscopy (SEM).Results show that increasing the magnetic field strength reduces both the alloy solidification temperature range and the dendrite coherency temperature,which increases the feeding time during solidification and decreases the HTS of the alloy.When the magnetic field parameters are 10 Hz 15 A,the EV31 alloy shows the lowest HTS.The main component of the second phase in the microstructure is Mg12Nd.This study also found that the electromagnetic field can effectively refine the grains,purify the melt,and reduce the oxide content in the melt.The obtained simulation results are consistent with the experimental results.

Microbial diversity in the hydrate-containing and-free surface sediments in the Shenhu area, South China Sea

Microbial diversity in the hydrate-containing （sites SH3B and SH7B） and -free （sites SHIB, SH5B, SH5C） sediments collected from the Shenhu area of the South China Sea （SCS） was investigated using 16S rRNA gene phylogenetic analysis. The phylogenetic results indicate difference in microbial communities be- tween hydrate-containing and -free sediments. At the gas hydrate-containing sites, bacterial communities were dominated by Deltaproteobacteria （30.5%）, and archaeal communities were dominated by Miscellaneous Crenarchaeotic Group （33.8%）; In contrast, Planctomycetes was the major group （43.9%） in bacterial communities, while Marine Benthic Group-D （MBG-D） （32.4%） took up the largest proportion in the archaeal communities. Moreover, the microbial communities have characteristics different from those in other hydrate-related sediments around the world, indicating that the presence of hydrates can affect the microbial distribution. In addition, the microbial community composition in the studied sediments has its own uniqueness, which may result from co-effect of geochemical characteristics and presence/absence of hydrate.

Silicon on Insulator with Highly Uniform Top Si Fabricated by H/He Coimplantation

Silicon on insulator with highly uniform top Si is fabricated by co-implantation of H+and He+ions. Compared with the conventional ion-slicing process with H implantation only, the co-implanted specimens whose He depth is deeper than H profile have the top Si layer with better uniformity after splitting. In addition, the splitting occurs at the position that the maximum concentration peak of H overlaps with the secondary concentration peak of He after annealing. It is suggested that the H/He co-implantation technology is a promising approach for fabricating fully depleted silicon on insulator.

Resistivity and Radio-Frequency Properties of Two-Generation Trap-Rich Silicon-on-Insulator Substrates

Crystal morphologies and resistivity of polysilicon trap-rich layers of two-generation trap-rich silicon-on-insulator（TR-SOI） substrates are studied. It is found that the resistivity of the trap-rich layer of generation 2（TR-G2）is higher than that of generation 1（TR-G1）, although the crystal morphologies of the trap rich layers are the same. In addition, the rf performance of two-generation TR-SOI substrates is investigated by coplanar waveguide lines and inductors. The results show that both the rf loss and the second harmonic distortion of TR-G2 are smaller than those of TR-G1. These results can be attributed to the higher resistivity values of both the trap-rich layer and the high-resistivity silicon（HR-Si） substrate of TR-G2. Moreover, the rf performance of the TR-SOI substrate with thicker buried oxide is slightly better. The second harmonics of various TR-SOI substrates are simulated and evaluated with the harmonic quality factor model as well. It can be predicted that the TR-SOI substrate will see further improvement in rf performance if the resistivities of both the trap-rich layer and HR-Si substrate increase.

Editorial: Special issue on “Internet of things and edge computing in the new 5G era”

1.Introduction Recently,edge computing has evolved from concept to early-stage implementations because new use cases require a more remote computing and networking approach than a conventional,fully cloud-based model.Many companies,network providers and cloud companies are testing and launching early commercial products in the developed markets of the United States,Europe,China and Asia Pacific.Although progress in edge trials continues,key issues remain to be resolved around the most viable location of the edge,the scale of the required edge investment,and the actual business models.

Numerical study of the influence of the atmospheric pressure on the thermal environment in the passenger cabin

The cabin air pressure remains lower than the horizontal atmospheric pressure when the airplane is in flight.Air pressure is one of the parameters that must be taken into consideration while studying the thermal environment of an airplane cabin.There are still no reference values for aircraft cabins despite the fact that numerous studies on low pressure heat transfer have demonstrated the connection between convective heat transfer coefficient(CHTC)and air pressure.In this paper,a correction method for CHTC under low pressure conditions was established by using the dummy heat dissipation in the low-pressure cabin experiment.On this basis,a thermal environment simulation model was developed,then was applied to the simulation of a seven-row aircraft cabin containing 42 passengers,and the CHTC and heat loss of dummy surface in the cabin were obtained.Finally,the results of PMV calculated by using heat dissipation and air parameters at sampling points were compared.The results show that the modified CHTC can accurately reflect the cabin thermal environment under low pressure conditions,and the correction of CHTC can be realized by adjusting the turbulent Prandtl number,which is nonlinear correlated with the pressure.The simulation results of the thermal environment in the seven-row cabin show that the CHTC changes by about 42%before and after modification.The air pressure decreases during take-off,which reduces the average CHTC of the crew surface from 5.09 W/(m^(2)·K)to 4.56 W/(m^(2)·K),but the air temperature rises by about 0.2°C as a whole.The deviation of PMV results calculated by using simulated heat loss data and using air parameters of measuring points in space is up to 0.5,but the latter is representative for calculating the thermal comfort level of the whole cabin.

数据赋能高校治理新模式探究

当前高校业务管理信息化仍存在运行机制、统筹能力、队伍建设等诸多问题,文章从高校业务管理过程的人性化与智能化角度出发,提出“人本、协同、共享”的建设思路。在业务管理系统建设过程中,以网络全连接为脉络,以数据全连接为经络,在经脉贯通的基础上融合业务管理和师生服务需求,实现智慧校园建设中的“三通”,即网络通、数据通、业务通;并以中国矿业大学建设实践为例,构建数据赋能的高效治理体系,结合业务管理系统的建设目标转变、建设方式转变、数据共享模式转变,形成以“三转”促“三通”的业务管理系统建设新模式。

定优胶在水溶液中的构象转变

定优胶为菌种需氧发酵产生的生物多糖,迄今为止,仍未有关于定优胶在水溶液中的链构象转变的研究。文中采用圆二色谱与光散射初步研究了定优胶在水溶液中的链构象,利用超灵敏差示扫描微量热仪与流变仪研究了温度、极性溶剂二甲基亚砜(DMSO)与强碱NaOH对定优胶分子链构象的影响。结果表明,定优胶在水溶液中为通过氢键来维持的刚性棒状螺旋构象,高温、极性溶剂及NaOH皆能破坏氢键作用,促使螺旋结构转变为无规分子链。在100℃左右时,定优胶双螺旋结构发生解旋;高含量的DMSO将破坏定优胶的双螺旋结构;在研究的NaOH浓度范围内(0~0.3 mol/L),部分定优胶分子链发生构象转变。故定优胶溶液具备优异的耐热、耐强碱的性能,在极性溶剂中也有良好的稳定性。

Mobile Edge Communications, Computing, and Caching(MEC3) Technology in the Maritime Communication Network

With the increasing maritime activities and the rapidly developing maritime economy, the fifth-generation(5G) mobile communication system is expected to be deployed at the ocean. New technologies need to be explored to meet the requirements of ultra-reliable and low latency communications(URLLC) in the maritime communication network(MCN). Mobile edge computing(MEC) can achieve high energy efficiency in MCN at the cost of suffering from high control plane latency and low reliability. In terms of this issue, the mobile edge communications, computing, and caching(MEC3) technology is proposed to sink mobile computing, network control, and storage to the edge of the network. New methods that enable resource-efficient configurations and reduce redundant data transmissions can enable the reliable implementation of computing-intension and latency-sensitive applications. The key technologies of MEC3 to enable URLLC are analyzed and optimized in MCN. The best response-based offloading algorithm(BROA) is adopted to optimize task offloading. The simulation results show that the task latency can be decreased by 26.5’ ms, and the energy consumption in terminal users can be reduced to 66.6%.

Microbial diversity in cold seep sediments from the northern South China Sea

South China Sea （SCS） is the largest Western Pacific marginal sea. However, microbial studies have never been performed in the cold seep sediments in the SCS. In 2004, ＂SONNE＂ 177 cruise found two cold seep areas with different water depth in the northern SCS. Haiyang 4 area, where the water depth is around 3000 m, has already been confirmed for active seeping on the seafloor, such as microbial mats, authigenic carbonate crusts and bivalves. We investigated microbial abundance and diver- sity in a 5.55-m sediment core collected from this cold seep area. An integrated approach was employed including geochemistry and 16S rRNA gene phylogenetic analyses. Here, we show that microbial abun- dance and diversity along with geochemistry profiles of the sediment core revealed a coupled reaction between sulphate reduction and methane oxidation. Acridine orange direct count results showed that microbial abundance ranges from 105 to 106 cells/g sediment （wet weight）. The depth-related variation of the abundance showed the same trend as the methane concentration profile. Phylogenetic analysis indicated the presence of sulphate-reducing bacteria and anaerobic methane-oxidizing archaea. The diver- sity was much higher at the surface, but decreased sharply with depth in response to changes in the geochemical conditions of the sediments, such as methane, sulphate concentration and total organic carbon. Marine Benthic Group B, Chloroflexi and JS1 were predominant phylotypes of the archaeal and bacterial libraries, respectively.

新型分子检测技术在基层实验室诊断肺结核的效能分析

目的分析与比较GeneXpert MTB/RIF(简称“GeneXpert”)与交叉引物核酸恒温扩增(cross-priming amplification,CPA)技术在基层实验室结核病快速诊断中的效能。方法连续收集黑龙江省五常市结核病防治所2014年4月至2017年7月初诊肺结核可疑患者的痰标本,分别进行改良罗氏固体培养基培养法(简称“固体培养法”)与快速分子检测(A组采用GeneXpert检测了787例;B组采用CPA检测了501例)。以固体培养法为标准,计算2种分子检测技术的敏感度、特异度、Kappa值。结果A组共检测787例患者痰标本,其中培养阳性229例,GeneXpert阳性300例,GeneXpert检测的敏感度、特异度分别为99.1%(227/229)、86.9%(485/558),Kappa=0.788。B组共检测501例患者痰标本,其中培养阳性129例,CPA检测阳性125例。CPA检测的敏感度、特异度分别为81.4%(105/129)、94.6%(352/372),Kappa=0.768。2种分子检测技术与固体培养法检测结果的一致率比较,差异无统计学意义[90.5%(712/787)vs91.2%(457/501);χ^2=0.204,P=0.652)]。结论CPA检测的准确性与GeneXpert相当,但其成本低、无需检测仪器、允许每批次大量样本同时操作,更适用于基层实验室对肺结核患者的早期诊断。

Effects of dietary fiber on human health

Dietary fiber(DF)is believed to provide important health benefits and it has become a research hotspot.DF exists in most natural foods,including fruits(16.74%-91.24%),vegetables(6.53%-85.19%),grains(9.76%-69.20%)and so on.DF has different physicochemical properties such as water holding capacity(WHC)(2.01-25.03 g/g),water swelling capacity(WSC)(0.95-23.90 mL/g),oil holding capacity(OHC)(0.65-29.00 g/g),glucose adsorption capacity(GAC)(0.17-4.65 mmol/g),cholesterol adsorption capacity(CAC)(0.03-37.10 mg/g)and viscosity,which make it exhibits different physiological functions such as reducing the risk of obesity,diabetes,cancer,and intestinal diseases.On the basis of consulting related databases,the physicochemical properties of DF and its derived physiological functions are reviewed.It is found that DF has effect on the prevention and treatment of obesity due to good WHC,WSC,OHC and CAC.Good GAC can relieve the symptoms of diabetes.The physicochemical properties of WHC and WSC can reduce the risk of cancer.The WHC,WSC and viscosity are beneficial to intestinal health.

Catheter ablation for atrial fibrillation is associated with reduced risk of mortality in the elderly:a prospective cohort study and propensity score analysis

Background It is unclear whether catheter ablation(CA)for atrial fibrillation(AF)affects the long-term prognosis in the elderly.This study aims to evaluate the relationship between CA and long-term outcomes in elderly patients with AF.Methods Patients more than 75 years old with non-valvular AF were prospectively enrolled between August 2011 and December 2017 in the Chinese Atrial Fibrillation Registry Study.Participants who underwent CA at baseline were propensity score matched(1:1)with those who did not receive CA.The outcome events included all-cause mortality,cardiovascular mortality,stroke/transient ischemic attack(TIA),and cardiovascular hospitalization.Results Overall,this cohort included 571 ablated patients and 571 non-ablated patients with similar characteristics on 18 dimensions.During a mean follow-up of 39.75±19.98 months(minimum six months),24 patients died in the ablation group,compared with 60 deaths in the non-ablation group[hazard ratio(HR)=0.49,95%confidence interval(CI):0.30-0.79,P=0.0024].Besides,6 ablated and 29 non-ablated subjects died of cardiovascular disease(HR=0.25,95%CI:0.11-0.61,P=0.0022).A total of 27 ablated and 40 non-ablated patients suffered stroke/TIA(HR=0.79,95%CI:0.48-1.28,P=0.3431).In addition,140 ablated and 194 non-ablated participants suffered cardiovascular hospitalization(HR=0.84,95%CI:0.67-1.04,P=0.1084).Subgroup analyses according to gender,type of AF,time since onset of AF,and anticoagulants exposure in initiation did not show significant heterogeneity.Conclusions In elderly patients with AF,CA may be associated with a lower incidence of all-cause and cardiovascular mortality.

Construction of BiVO4 nanosheets@WO3 arrays heterojunction photoanodes by versatile phase transformation strategy

A versatile phase transformation strategy was proposed to synthesize novel BiVO4 nanosheets(NSs)@WO3 nanorod(NR)and nanoplate(NP)arrays films.The strategy was carried out by following a three-step hydrothermal process(WO3→WO3/Bi2WO6→WO3/BiVO4).According to the characterization results,plenty of BiVO4 NSs grew well on the surface of WO3 NR and NP arrays films,thus forming the WO3/BiVO4 heterojunction structure.The prepared WO3/BiVO4 heterojunction films were used as the photoanodes for the photoelectrochemical(PEC)water splitting.As indicated by the results,the photoanodes exhibited an excellent PEC activity.The photocurrent densities of the WO3/BiVO4 NR and NP photoanodes at 1.23 V(vs RHE)without cocatalyst under visible light illumination reached up to about 1.56 and 1.20 mA/cm2,respectively.

A 5G Virtualized RAN Based on NO Stack

The virtualized radio access network(v RAN) could implement virtualized baseband functions on general-purpose platforms and expand the processing capacity of the radio access network(RAN) significantly.In this paper,a Not Only Stack(NO Stack) based vR AN is proposed to be employed in the fifth generation(5G) mobile communication system.It adopts advanced virtualization technologies to maintain flexible and sustainable.The baseband processing and storage resources should be sliced and orchestrated agilely to support multi radio access technology(multiRAT) .Also it is analyzed and demonstrated by different use cases to validate the benefits.The proposed v RAN reduces signaling overheads and service response time in the bearer establishment procedure.Concluded from the analyses and demonstrations,the NO Stack based v RAN could support multi-RAT convergence and flexible networking effectively.

Structural and mechanical properties of 7075 alloy strips fabricated by roll-casting in a static magnetic field

The influences of a 0.2 T static magnetic field on the microstructure of 7075 aluminum alloys sheets produced with a twin-roll continuous caster at 675℃ were investigated in this paper. Under a uniform magnetic field, the primary dendrites were refined and tended to be equiaxed. The microstructure consisted of an intermediate case between dendritic and equiaxed grains. Moreover, the use of an external static field in the twin-roll casting process can reduce heat discharge, resulting in a decrease in undercooling, and may also account for the abatement of segregation bands. In addition, the static magnetic field effectively improved the solute mixing capacity, and the added atoms more easily diffused from precipitates to theα-Al matrix, which resulted in an increase in the mechanical properties of the rolled sheets. Specimens prepared both in the presence of a static magnetic field and in the absence of a static magnetic field exhibited brittle-fracture characteristics.