Mesoscale and Microphysical Characteristics of a Double Rain Belt Event in South China on May 10–13,2022

A second rain belt sometimes occurs ahead of a frontal rain belt in the warm sector over coastal South China,leading to heavy precipitation.We examined the differences in the mesoscale characteristics and microphysics of the frontal and warm sector rain belts that occurred in South China on May 10–13,2022.The southern rain belt occurred in an environment with favorable mesoscale conditions but weak large-scale forcing.In contrast,the northern rain belt was related to low-level horizontal shear and the surface-level front.The interaction between the enhanced southeasterly winds and the rainfall-induced cold pool promoted the persistent growth of convection along the southern rain belt.The convective cell propagated east over the coastal area,where there was a large temperature gradient.The bow-shaped echo in this region may be closely related to the rear-inflow jet.By contrast,the initial convection of the northern rain belt was triggered along the front and the region of low-level horizontal shear,with mesoscale interactions between the enhanced warm-moist southeasterly airflow and the cold dome associated with the earlier rain.The terrain blocked the movement of the cold pool,resulting in the stagnation of the frontal convective cell at an early stage.Subsequently,a meso-γ-scale vortex formed during the rapid movement of the convective cell,corresponding to an enhancement of precipitation.The representative raindrop spectra for the southern rain belt were characterized by a greater number and higher density of raindrops than the northern rain belt,even though both resulted in comparable hourly rainfalls.These results help us better understand the characteristics of double rain belts over South China.

利用改良的CRISPR/Cas9n double nick系统构建DPF2基因敲除的人胰腺癌PANC-1细胞株

目的利用改良的CRISPR/Cas9n double nick系统构建DPF2基因敲除的PANC-1人胰腺癌细胞模型。方法设计两对靶向DPF2基因第四外显子上下游的单链向导RNA(single guide RNA,sgRNA),化学合成sgRNA寡核苷酸序列,并克隆至pGL3-U6-sgRNA-PGK-puromycin真核表达质粒中。将克隆正确的DPF2-sgRNA重组真核表达质粒与Cas9真核表达载体pST1374-N-NLS-flag-linker-Cas9共转染至PANC-1细胞中,通过嘌呤霉素和杀稻瘟菌素筛选阳性转染细胞,进一步通过有限稀释法筛选获得单克隆细胞株。提取细胞基因组DNA对敲除位点进行聚合酶链反应(PCR)鉴定和测序鉴定。Western blot检测细胞中DPF2蛋白表达情况。结果sgRNA成功插入pGL3-U6-sgRNA-PGK-puromycin中且序列正确。PCR扩增鉴定和测序结果表明,PANC-1细胞中一段包括完整第四外显子在内的长度为401 bp的DPF2基因片段被敲除。Western blot检测结果表明,DPF2基因敲除细胞中的DPF2蛋白表达缺失。结论通过改良的CRISPR/Cas9n double nick基因编辑系统成功构建DPF2基因敲除PANC-1稳定细胞株。

Development and identification of a dwarf wheat-Leymus mollis double substitution line with resistance to yellow rust and Fusarium head blight

Leymus mollis (Trin.) Pilger (2n = 4x = 28, NsNsXmXm,), a wild relative of common wheat, possesses many potentially valuable traits for genetic improvement of wheat, including strong, short stems, long spikes with numerous spikelets, tolerance to drought and cold stresses, and resistance to many fungal and bacterial diseases. In the present study, a wheat-L. mollis double substitution line DM96 was selected from a F6 progeny of a cross between M842-16 (an octoploid Tritileymus line) and D4286 (a Triticum durum line) using genomic in situ hybridization (GISH), simple sequence repeat (SSR) markers, and expressed sequence tagged sequence site (EST-STS) markers. Chromosome analysis at mitosis and meiosis showed that DM96 had a chromosome constitution of 2n = 42 = 21II. GISH analysis indicated that DM96 carried 38 chromosomes from wheat and two homologous pairs of Ns chromosomes from L. mollis. Fluorescent in situ hybridization (FISH) showed that chromosomes 2Ns and 3Ns from L. mollis had replaced wheat chromosomes 2D and 3D in DM96, which was confirmed by SSR and STS markers. The newly developed substitution line DM96 has shorter height, longer spikes and more kernels than its parents and showed high resistance to stripe rust and Fusarium head blight (FHB). Thus, this line is a new bridge material for the production of useful translocation lines for wheat genetic research and genetic improvement of wheat yield and disease resistance in breeding programs.

Development and genetic analysis of wheat double substitution lines carrying Hordeum vulgare 2H and Thinopyrum intermedium 2Ai#2 chromosomes

Thinopyrum intermedium and barley are two close relatives of wheat and carry many genes that are potentially valuable for the improvement of various wheat traits. In this study we created wheat double substitution lines by hybridizing different wheat–Th. intermedium and wheat–barley disomic alien substitution lines, with the aim of using genes in Th. intermedium and barley for wheat breeding and investigating the genetic behavior of alien chromosomes and their wheat homoeologs. As expected, we obtained two types of wheat double substitution lines,2D2Ai#2(2B)2H( A) and 2A2 Ai#2(2B)2H(2D), in which different group 2 wheat chromosomes were replaced by barley chromosome 2 H and Th. intermedium chromosome 2Ai#2. The new materials were characterized using molecular markers, genomic in situ hybridization(GISH), and fluorescent in situ hybridization(FISH). GISH and FISH experiments revealed that the double substitution lines harbor 42 chromosomes including 38 wheat chromosomes, a pair of barley chromosomes, and a pair of Th. intermedium chromosomes. Analysis using specific DNA markers showed that two pairs of wheat homoeologous group 2 chromosomes in the new lines were substituted by a pair of 2H and a pair of 2Ai#2 chromosomes. Chromosome 2H showed a higher transmission rate than 2Ai#2, and both chromosomes were preferentially transmitted between generations via female gametes. Evaluation of botanic and agronomic traits demonstrated that,compared with their parents, the new lines showed similar growth habits and plant type but differences in plant height, flowering date, and self-fertility. Cytological observations using different probes suggested that the double substitution lines showed nearly normal genetic behavior before and during meiosis. The novel substitution lines can potentially be used in wheat meiosis research and breeding programs.

Evaluation matrix with the speed feature based on double inspiriting control lines

Methods of the comprehensive evaluation have been studied for many years. However, the change speed of evaluated objects was rarely considered by the existing evaluation methods. An evaluation matrix is proposed to remedy this deficiency. Firstly, the change speed state （CSS） of the evaluated objects is analyzed based on double inspiriting control lines （DICLs）, and a matrix of the CSS is constructed. Then, 72 elements in the matrix are analyzed, and formulas describing each CSS are given. The efficiency of the proposed evaluation matrix is proved when the CSS merges with the change speed trend （CST） in the dynamic comprehensive evaluation. Finally, a computing example shows that the proposed evaluation matrix is feasible in the dynamic comprehensive evaluation with the speed feature.

The design of double line five step ship lock of Three Gorges Project

The general design and layout of the double-line five-step ship-lock,the water delivery technique for high head ship-lock,the key technical problems of fully lined ship-lock and the monitoring techniques for large-scale miter gates and hoisting equipment under complicated operation conditions of Three Gorges Project (TGP) are introduced.Since the operation of ship-lock in 2003,the operation practice has proved that the design techniques are advanced,rational and reliable.The design and construction of the fully lined ship-lock promotes the development of design theory and practice of ship-lock projects,which makes the construction technology of ship-lock in the world reach a new level.

Assembly Line Balancing Based on Double Chromosome Genetic Algorithm

Aiming at assembly line balancing problem,a double chromosome genetic algorithm(DCGA)is proposed to avoid trapping in local optimum,which is a disadvantage of standard genetic algorithm(SGA).In this algorithm,there are two chromosomes of each individual,and the better one,regarded as dominant chromosome,determines the fitness.Dominant chromosome keeps excellent gene segments to speed up the convergence,and recessive chromosome maintains population diversity to get better global search ability to avoid local optimal solution.When the amounts of chromosomes are equal,the population size of DCGA is half that of SGA,which significantly reduces evolutionary time.Finally,the effectiveness is verified by experiments.

Research into Freedom Surface Modeling System of Double Beta Spline in Space

In this paper, we present the double Beta spline curved surface which is controlled by double parameters including the algorithm principles, the treatment of boundary conditions, the alternation of projection, the algorithms of elimination hiddle line, the process to display and the primiples to produce the shaded curved surface. Based on all the above, a freedom surface modeling system (FSMS) is designed and some examples developed on FSMS are verified and analyzed.

Process Analysis of Double Circuit Transmission Line Trip-out on the Same Tower Due to Lightning

In recent years,several failures of double circuit transmission line on the same tower due to lightning were happened in Beijing power grid.Although it can be reclosed successful,the lightning strike caused a grave threat to the power grid security.The cause of the accident and the accident process were studied for the sake of further understanding of the impact of lightning on power grid.As an example,110 kV double circuit transmission line(Xilong-line) was analyzed.At first,the system topology was given.Through the analysis on relay protection actions and the fault recorder data,over voltage on the insulator strings was calculated.Based on the analysis and the calculation,accident cause and the process were presented respectively.Secondly,it comes to the conclusion that the lightning failure was caused by counterattack.The wave of the lightning over voltage would spread to the not grounded neutral point of the transformers,and make the neutral protective gap breakdown,then cause freewheeling with the frequency of 50 Hz.As results of the relay protection,the double circuit transmission line all tripped out.Finally,the causes of the accident were proposed that included terrain features,large corner towers,strong thunderstorm weather and poor grounded contact of the tower.

Fault location of two-parallel transmission line for double phase-to-earth fault using one-terminal data

An accurate algorithm for fault location of double phase-to-earth fault on transmission line of direct ground neutral system is presented. The algorithm, which employs the faulted phase network and zero-sequence network as fault-location model in which the source impedance at the remote end is not involved, ef-fectively eliminates the effect of load flow and fault resistance on the accuracy of fault location. The algorithm achieves accurate location by measuring only one local end data and is used in a procedure that provides automatic determination of faulted types and phases, and does not require the engineer to specify them. Simulation results showed the effectiveness of the algorithm under the condition of double phase-to-earth fault.

A Novel Fault Location Algorithmfor Double-Circuit Transmission Lines based on Distributed Parameter

Anewfault location algorithmfor double-circuit transmissionlines is described inthis paper.Theproposed method uses data extractedfromtwo ends of the transmissionlines andthus eliminates the effects ofthe source impedance andthe fault resistance.The distributed parameter model and the modal transformationare also employed.Depending on modal transformation,the coupled equations of the lines are converted intodecoupled ones.Inthis way,the mutual coupling effects between adjacent circuits of the lines are eliminatedandtherefore an accurate fault location can be achieved.The proposed methodis tested via digital simulationusing EMTP in conjunction with MATLAB.The test results corroborate the high accuracy of the proposedmethod.

Fault Locator Using Two-end Unsynchronized Measurements for UHV Series Compensated Double-circuit Lines

An accurate fault location algorithm for double-circuit series compensated lines is presented.Use of two-end unsynchronized measurements of current and voltage signals is considered.The algorithm applies two subroutines,designated for locating faults on particular line sections,and additionally the procedure for selecting the valid subroutine.The subroutines are formulated with use of the generalized fault loop model and the distributed parameter line model is applied.Performed ATP-EMTP based evaluation has shown the validity of the derived fault location algorithm and its high accuracy.

The Optimizing Model and Its Solution for Making Train Working Graph with Computer on Separative Division of Double－Track Lines

The authoros specialize in the field of optunization and automatic programme oftrain working graph. In this peper, at frist, a mixed 0-1 integer progranimingmodel about this problem for duuble-track lines is set up, then the principle andProcess of selution are stated, with an application exaiiiple put forward.

Study on dynamic optimization of the double railway suspended vehicle for automatic transportation in the welding shop

The 2DOF dynamic equations of the doable railway suspended vehicle for automatic transportation in the welding shop are established. The sensitivities are analyzed. The parameter design is researched in ADAMS in terms of the inner railway radius, wheelbase, gauge, girder length of the doable railway suspended vehicle for automatic transportation in the welding product line. The mutual-restriction among the design variables is discussed and the selective ranges of the variables are confirmed. The result shows that the stability of the doable railway suspended vehicle for automatic transportation in the welding product line depends on parameters of the inner railway radius, wheelbase, gauge, girder length. The optimal results of the optimal objective and design variables have research significance for the virtual prototype of the doable suspension railway automation vehicle. The optimal results are input into the simulation model iteratively and the simulation results are fed back to the physical prototype. The veracity and reliability of peoformance forecast are improved so that the manufacture cost of the doable suspension railway automation vehicle is reduced significantly.

A G-band terahertz monolithic integrated amplifier in 0.5-μm InP double heterojunction bipolar transistor technology

Design and characterization of a G-band（140–220 GHz） terahertz monolithic integrated circuit（TMIC） amplifier in eight-stage common-emitter topology are performed based on the 0.5-μm In Ga As/In P double heterojunction bipolar transistor（DHBT）. An inverted microstrip line is implemented to avoid a parasitic mode between the ground plane and the In P substrate. The on-wafer measurement results show that peak gains are 20 dB at 140 GHz and more than 15-dB gain at 140–190 GHz respectively. The saturation output powers are-2.688 dBm at 210 GHz and-2.88 dBm at 220 GHz,respectively. It is the first report on an amplifier operating at the G-band based on 0.5-μm InP DHBT technology. Compared with the hybrid integrated circuit of vacuum electronic devices, the monolithic integrated circuit has the advantage of reliability and consistency. This TMIC demonstrates the feasibility of the 0.5-μm InGaAs/InP DHBT amplifier in G-band frequencies applications.

A New Type of Double-Lumen Catheter to Replace Current One in RCA

Objective: To replace the peripheral venous puncture for blood sampling with taking blood samples extracorporally from arterial line before predilution during RCA-CRRT performed. Methods: A new type of double-lumen femoral catheter was used instead of the current tubes. The new type of double-lumen tube had a greater distance from the inner venous ports to the inner arterial ports than current tubes. The minimum distance from the venous port to the arterial port was greatly lengthened. Replacement solution contained citrate, zero Ca2+, zero bicarbonate, low Na+. Blood samples were synchronously collected from the arterial line before the infusion of citrate replacement fluid and from the peripheral vein. The iCa concentration data of two groups were analyzed to observe the difference between iCa concentration levels in the arterial line and in peripheral vein;the anticoagulant effect of RCA and possible complications were observed, such as bleeding, clottings and hypocalcaemia. Results: 28 times of RCA-CRRT were performed on17 AKI and CRF patients with active bleeding or at the high risk of bleeding;336 blood samples were collected. Statistics showed that the difference of iCa concentration between arterial line group and the peripheral vein group was not significant (P = 0.9), there is a high degree of similarity between the iCa concentration of arterial line blood and the peripheral venous blood. None of the patients developed citrate toxicity or metabolic alkalosis. None induced bleeding, or bleeding aggravated. No obvious clotting occurred. Systemic calcium concentration was achieved in the ideal range. Conclusion: In clinical practice, the data of iCa concentration from arterial line can be used to replace that from peripheral vein when the new type of double-lumen femoral catheter is placed in femoral vein. RCA-CRRT therapy is safe and effective.

土与强风化岩双元边坡圆弧-平面破坏模式与支护设计方法

为了探究土与强风化岩边坡中强风化岩不破坏的临界坡率及稳定性判断方法,基于济南地层,得出适用于数值模拟的土层参数,并利用强度折减法求出边坡的临界坡率,为施工提供参考。针对强风化岩不破坏的边坡,运用改进的瑞典条分法求出边坡安全系数解析解,并利用滑移线场法求出滑移线,为安全系数解析解的应用提供依据。结果表明,岩层厚度超过边坡高度1/2或坡率大于1:0.5时,强风化岩一定破坏;解析解得出的安全系数偏小,有利于工程安全;针对土与强风化岩边坡,文中结果可确定边坡破坏区域,设计支护方案。

特勒根似功率保护在同塔双回交流输电线路中的应用

随着我国电网规模快速扩张,输电通道资源日渐紧缺,同塔多回输电技术逐渐得到广泛应用。超/特高压远距离输电线路一般以差动保护作为双重主保护,与纵联距离/方向保护构成双重化配置。但用于同塔双回输电线路时,分布电容电流将影响差动保护的灵敏度;同时,由于双回线线间和相间较强的电磁耦合作用,线间互感的影响将会降低纵联距离、纵联方向保护判断的正确性,导致原来的保护配置方案难以直接应用。将特勒根似功率保护原理推广至同塔双回线路,提出了一种基于特勒根似功率定理的同塔双回输电线路纵联保护方法,能够不受双回线内部复杂电磁耦合、分布电容、系统负荷等影响,并验证了该保护的对时方案在双回线路中的适用性。采用MATLAB/Simulink仿真软件搭建1000kV特高压同塔双回输电线示范工程模型,经大量仿真实验,验证了所提保护方法的有效性。

改进的迈克尔逊干涉仪测量钠黄光双线波长差

在迈克尔逊干涉仪实验教学及科学研究过程中发现齿轮经常脱扣的现象,这对测量结果产生了严重影响。本文中,我们将传统的齿轮咬合式迈克尔逊干涉仪改进为杠杆式迈克尔逊干涉仪,有助于避免齿轮咬合式迈克尔逊干涉仪中多个齿轮间容易脱扣的现象。利用钠光灯照射杠杆式迈克尔逊干涉仪,观察到了明显的光拍干涉图样,测量了钠黄光双线波长差。钠黄光双线波长差的测量结果为0.5953±0.0054(nm)。本文的研究有助于提升迈克尔逊干涉仪装置的测量稳定性,实现在光谱定标、光学传感、生化检测等领域的长期稳定使用;有助于提升学生发现问题、解决问题的能力;以及有助于学生提升将不同科目知识相结合的能力。

基于修正Loganathan公式的非水平布置双线平行盾构隧道施工引起土体位移计算方法

[目的]为研究双线平行盾构隧道非水平布置方式下,由施工引起的周围土体位移规律,提出一种基于修正Loganathan公式的土体位移计算方法。[方法]介绍了Loganathan公式及相关假设;考虑盾构隧道开挖扰动引起的地层损失、土体卸荷回弹和土体损失率沿掘进路径变化的综合影响,修正Loganathan公式并建立单线盾构隧道周围土体位移解;建立双线平行盾构隧道非水平布置方式下,由施工引起的土体位移计算方法;通过实际工程的现场监测和数值模拟结果,验证所提计算方法的工程适用性。[结果及结论]所提计算方法能够考虑隧道轴心连线与水平面夹角、双线隧道半径、隧道轴心间距、双线隧道埋深等双线隧道布置因素,以及隧道盾构施工扰动造成的地层损失、土体卸荷回弹和土体损失率沿掘进路径变化等施工因素对土体位移的影响。地面沉降及土体水平位移的理论计算结果同现场监测结果和数值模拟结果之间的平均误差分别为5.6%、0.6%和5.5%、5.3%,均满足工程经验规定的20%的精度要求,说明所提计算方法能够有效解决双线平行盾构隧道非水平布置方式下施工引起的土体位移计算问题,具有良好的工程适用性。