Er∶YAG激光SWEEPS双脉冲模式激活荡洗在自由水域中的气泡动力学观测

目的:探究Er∶YAG激光光子增强的光声流(SWEEPS)技术在不同脉冲间隔参数条件下的蒸汽气泡动力学效应。方法:Er∶YAG激光手具连接工作尖放置于自由水域模型中,设置SWEEPS模式,150~600μs脉冲间隔激活。高速摄像机(200 000 Hz)摄录Er∶YAG激光激活荡洗引起空穴效应的过程,matlab逐帧分析蒸汽气泡间的相互作用关系,及蒸汽气泡消失时刻气泡残余与激光工作尖之间的距离。实验数据经SPSS 19.0统计软件进行统计分析。结果:在自由水域中,Er∶YAG激光SWEEPS模式下,脉冲间隔设置的改变会引起两次脉冲激发的蒸汽气泡形成不同的相互作用关系,包括双气泡融合、双气泡撞击及双气泡脱离。其中,脉冲间隔设置为360~440μs时,双气泡撞击现象会使蒸汽气泡消失时气泡残余与激光工作尖之间达到最远距离。结论:在自由水域中,Er∶YAG激光双脉冲SWEEPS模式在不同的脉冲间隔设置下引起双气泡间形成不同的作用关系,该现象可能可以增强Er∶YAG激光空穴效应,强化激光激活荡洗的临床应用效果。

Alleviating hysteresis and improving device stability of perovskite solar cells via alternate voltage sweeps

The anomalous hysteresis in a perovskite solar cell induced by an asymmetric field is confirmed by a capacitance–voltage measurement. By applying several cycles of alternating reverse and forward scans, this hysteresis phenomenon is obviously alleviated, resulting in a hysteresis-less state in the perovskite solar cell. Meanwhile, the open-circuit voltage and power conversion efficiency of the perovskite solar cell are enhanced by 55.74% and 61.30%, respectively, while the current density and fill factor keep almost invariable. The operation of alleviating hysteresis is essential for further research and is likely to bring in performance gains.

Second-order phase correction of NMR spectra acquired using linear frequency-sweeps

NMR spectra acquired with experiments using frequency-sweeps such as the wide-band uniform-rate smooth truncation(WURST)spin-echo and Carr-Purcell-Meiboom-Gill(CPMG)sequences cannot be absorptively phased by using only conventional zerothand first-order phase correction.Implementation of phase correction up to the secondorder is described for obtaining absorptive spectra,which have more desirable line shapes and noise properties than magnitude spectra.The relationship of the second-order phase to the parameters of frequency sweeps is derived.The second-order phasing in the frequency-domain is equivalent to a point spread in the time-domain signal.The application of second-order phase correction is demonstrated with a wideline 35Cl CPMG spikelet spectrum.

Panda-monium Sweeps China

Pandas create sensation both online and offline Multiple levels of devotion exist within the panda fandom. A regular fan might be satisfied visiting the cuddly creatures in zoos just to enjoy their antics, while a “professional” one delves into pandas’ diet, behavior, personality, family trees and more.

Identification of new cotton fiber-quality QTL by multiple genomic analyses and development of markers for genomic breeding

Cotton fiber is one of the main raw materials for the textile industry.In recent years,many cotton fiber quality QTL have been identified,but few were applied in breeding.In this study,a genome wide association study(GWAS)of fiber-quality traits in 265 upland cotton breeding intermediate lines(GhBreeding),combined with genome-wide selective sweep analysis(GSSA)and genomic selection(GS),revealed 25 QTL.Most of these QTL were ignored by only using GWAS.The CRISPR/Cas9 mutants of GhMYB_D13 had shorter fiber,which indicates the credibility of QTL to a certain extent.Then these QTL were verified in other cotton natural populations,5 stable QTL were found having broad potential for application in breeding.Additionally,among these 5 stable QTL,superior genotypes of 4 showed an enrichment in most improved new varieties widely cultivated currently.These findings provide insights for how to identify more QTL through combined multiple genomic analysis to apply in breeding.

An adaptive finite-difference method for seismic traveltime modeling based on 3D eikonal equation

3D eikonal equation is a partial differential equation for the calculation of first-arrival traveltimes and has been widely applied in many scopes such as ray tracing,source localization,reflection migration,seismic monitoring and tomographic imaging.In recent years,many advanced methods have been developed to solve the 3D eikonal equation in heterogeneous media.However,there are still challenges for the stable and accurate calculation of first-arrival traveltimes in 3D strongly inhomogeneous media.In this paper,we propose an adaptive finite-difference(AFD)method to numerically solve the 3D eikonal equation.The novel method makes full use of the advantages of different local operators characterizing different seismic wave types to calculate factors and traveltimes,and then the most accurate factor and traveltime are adaptively selected for the convergent updating based on the Fermat principle.Combined with global fast sweeping describing seismic waves propagating along eight directions in 3D media,our novel method can achieve the robust calculation of first-arrival traveltimes with high precision at grid points either near source point or far away from source point even in a velocity model with large and sharp contrasts.Several numerical examples show the good performance of the AFD method,which will be beneficial to many scientific applications.

Sparse-Grid Implementation of Fixed-Point Fast Sweeping WENO Schemes for Eikonal Equations

Fixed-point fast sweeping methods are a class of explicit iterative methods developed in the literature to efficiently solve steady-state solutions of hyperbolic partial differential equations(PDEs).As other types of fast sweeping schemes,fixed-point fast sweeping methods use the Gauss-Seidel iterations and alternating sweeping strategy to cover characteristics of hyperbolic PDEs in a certain direction simultaneously in each sweeping order.The resulting iterative schemes have a fast convergence rate to steady-state solutions.Moreover,an advantage of fixed-point fast sweeping methods over other types of fast sweeping methods is that they are explicit and do not involve the inverse operation of any nonlinear local system.Hence,they are robust and flexible,and have been combined with high-order accurate weighted essentially non-oscillatory(WENO)schemes to solve various hyperbolic PDEs in the literature.For multidimensional nonlinear problems,high-order fixed-point fast sweeping WENO methods still require quite a large amount of computational costs.In this technical note,we apply sparse-grid techniques,an effective approximation tool for multidimensional problems,to fixed-point fast sweeping WENO methods for reducing their computational costs.Here,we focus on fixed-point fast sweeping WENO schemes with third-order accuracy(Zhang et al.2006[41]),for solving Eikonal equations,an important class of static Hamilton-Jacobi(H-J)equations.Numerical experiments on solving multidimensional Eikonal equations and a more general static H-J equation are performed to show that the sparse-grid computations of the fixed-point fast sweeping WENO schemes achieve large savings of CPU times on refined meshes,and at the same time maintain comparable accuracy and resolution with those on corresponding regular single grids.

A Research Progress of CO_(2)-Responsive Plugging Channeling Gels

In the heterogeneous reservoirs,CO_(2) flooding easily leads to CO_(2) gas channeling,which can seriously affect sweeping efficiency and reduce oil recovery.After thoroughly investigating the advantages and shortcomings of various CO_(2) plugging technologies,this paper focuses on the feasibility of improving conventional water-alternating gas(WAG)through CO_(2)-responsive gel materials.Based on the different chemical reaction mechanisms between the unique chemical structure and CO_(2),changes in the material’s physical and chemical properties can respond to CO_(2).The feasibility of utilizing these property changes for CO_(2)-responsive plugging is explored.Various CO_(2)-responsive gels and gel nanoparticles have been extensively researched in different fields,such as energy,medicine,and biology.This paper surveys the molecular structures,chemical compositions,response mechanisms,and changes of these CO_(2)-responsive gels,aiming to draw insights into the carbon dioxide-enhanced oil recovery(CO_(2)-EOR)field.Finally,the key issues and future development direction of CO_(2)-responsive plugging gels were analyzed.

A new broom sweeps clean:is there a Chinese-style political business cycle?

Politics is an important cause of economic growth and fluctuations.We present a new Political Business Cycle(PBC)Theory based on the background of recent Chinese economic transformation and government behaviors,explore the economic impact of the National Congress of the Communist Party of China(CPC),the National People’s Congress(NPC)and Chinese People’s Political Consultive Conference(CPPCC)and how they shape and influence the behaviors of local government officials.Based on 1994-2012 inter-provincial panel data of China and using SYS-GMM and LSDVC,we find that there are significant effects in China of PBC and government administration change.Changes in government administration influence the economic behaviors of local governments,which in turn influence local economic development through fiscal decentralization and political promotion tournament.These effects are sustained and robust.In this paper we offer an economic explanation for the Chinese proverb“a new broom sweeps clean,”and try to verify the Chinese-style Political Business Cycle(CPBC).We provide new ideas for further improving the functions of government,optimizing macroeconomic control,and preventing personnel changes in the government from overheating the economy.

Donald Tsang Sweeps in Again

Incumbent Hong Kong Chief Executive Donald Tsang Yam-kuen breezed through local elec- tions to soundly defeat rival Alan Leong on March 25, and move into his second term as the special administrative region’s top official.

Optimizing Parallel S_n Sweeps on Unstructured Grids for Multi-Core Clusters

In particle transport simulations, radiation effects are olden described by the discrete ordinates （Sn） form of Boltzmann equation. In each ordinate direction, the solution is computed by sweeping the radiation flux across the grid. Parallel Sn sweep on an unstructured grid can be explicitly modeled as topological traversal through an equivalent directed acyclic graph （DAG）, which is a data-driven algorithm. Its traditional design using MPI model results in irregular communication of massive short messages which cannot be efficiently handled by MPI runtime. Meanwhile, in high-end HPC cluster systems, multicore has become the standard processor configuration of a single node. The traditional data-driven algorithm of Sn sweeps has not exploited potential advantages of multi-threading of multicore on shared memory. These advantages, however, as we shall demonstrate, could provide an elegant solution resolving problems in the previous MPI-only design. In this paper, we give a new design of data-driven parallel Sn sweeps using hybrid MPI and Pthread programming, namely Sweep-H, to exploit hierarchical parallelism of processes and threads. With special multi-threading techniques and vertex schedule policy, Sweep-H gets more efficient communication and better load balance. We further present an analytical performance model for Sweep-H to reveal why and when it is advantageous over former MPI counterpart. On a 64-node multicore cluster system with 12 cores per node, 768 cores in total, Sweep-H achieves nearly linear scalability for moderate problem sizes, and better absolute performance than the previous times speedup on 64 nodes）. MPI algorithm on more than 16 nodes （by up to two

Scanning for Genomic Regions Subject to Selective Sweeps Using SNP-MaP Strategy

Population genomic approaches, which take advantages of high-throughput genotyping, are powerful yet costly methods to scan for selective sweeps. DNA-pooling strategies have been widely used for association studies because it is a cost-effective alternative to large-scale individual genotyping. Here, we performed an SNP-MaP （single nucleotide polymorphism microarrays and pooling） analysis using samples from Eurasia to evaluate the efficiency of pooling strategy in genome-wide scans for selection. By conducting simulations of allelotype data, we first demonstrated that the boxplot with average heterozygosity （HET） is a promising method to detect strong selective sweeps with a moderate level of pooling error. Based on this, we used a sliding window analysis of HET to detect the large contiguous regions （LCRs） putatively under selective sweeps from Eurasia datasets. This survey identified 63 LCRs in a European population. These signals were further supported by the integrated haplotype score （iHS） test using HapMap II data. We also confirmed the European-specific signatures of positive selection from several previously identified genes （KEL, TRPV5, TRPV6, EPHB6）. In summary, our results not only revealed the high credibility of SNP-MaP strategy in scanning for selective sweeps, but also provided an insight into the population differentiation.

Selective footprints and genes relevant to cold adaptation and other phenotypic traits are unscrambled in the genomes of divergently selected chicken breeds

Background The genomes of worldwide poultry breeds divergently selected for performance and other phenotypic traits may also be affected by,and formed due to,past and current admixture events.Adaptation to diverse environments,including acclimation to harsh climatic conditions,has also left selection footprints in breed genomes.Results Using the Chicken 50K_CobbCons SNP chip,we genotyped four divergently selected breeds:two aboriginal,cold tolerant Ushanka and Orloff Mille Fleur,one egg-type Russian White subjected to artificial selection for cold tolerance,and one meat-type White Cornish.Signals of selective sweeps were determined in the studied breeds using three methods:(1)assessment of runs of homozygosity islands,(2)F_(ST) based population differential analysis,and(3)haplotype differentiation analysis.Genomic regions of true selection signatures were identified by two or more methods or in two or more breeds.In these regions,we detected 540 prioritized candidate genes supplemented them with those that occurred in one breed using one statistic and were suggested in other studies.Amongst them,SOX5,ME3,ZNF536,WWP1,RIPK2,OSGIN2,DECR1,TPO,PPARGC1A,BDNF,MSTN,and beta-keratin genes can be especially mentioned as candidates for cold adaptation.Epigenetic factors may be involved in regulating some of these important genes(e.g.,TPO and BDNF).Conclusion Based on a genome-wide scan,our findings can help dissect the genetic architecture underlying various phenotypic traits in chicken breeds.These include genes representing the sine qua non for adaptation to harsh environments.Cold tolerance in acclimated chicken breeds may be developed following one of few specific gene expression mechanisms or more than one overlapping response known in cold-exposed individuals,and this warrants further investigation.

Polymer flooding: Current status and future directions

This review presents our perspective on the factors that have brought polymer flooding to its current state. Insights are provided on why HPAM is the dominant polymer used as well as what is needed to make alternative polymers and mobility-control methods viable. Explanation is given for why large polymer banks are needed for polymer flooding, and design of the injected polymer viscosity is detailed for cases with/without crossflow. The role of fractures and horizontal wells are discussed for improving injectivity and extending polymer flooding to recover oils with viscosities as high as 10,000 cP. Operational improvements are described to minimize mechanical and oxidative stability to allow HPAM polymers to be viable to 70 °C and ATBS polymers to 120 °C. Key factors affecting polymer retention are summarized. The paper points out unresolved issues and future directions for polymer flooding.

Influences of pore fluid on gas production from hydrate-bearing reservoir by depressurization

In addition to the temperature and pressure conditions,the pore fluid composition and migration behavior are also crucial to control hydrate decomposition in the exploitation process.In this work,to investigate the effects of these factors,a series of depressurization experiments were carried out in a visible one-dimensional reactor,using hydrate reservoir samples with water saturations ranging from 20%to 65%.The results showed a linear relationship between gas production rates and gas saturations of the reservoir,suggesting that a larger gas-phase space was conducive to hydrate decomposition and gas outflow.Therefore,the rapid water production in the early stage of hydrate exploitation could release more gas-phase space in the water-rich reservoir,which in turn improved the gas production efficiency.Meanwhile,the spatiotemporal evolution of pore fluids could lead to partial accelerated decomposition or secondary formation of hydrates.In the unsealed reservoir,the peripheral water infiltration kept reservoir at a high water saturation,which hindered the overall production process and caused higher water production.Importantly,depressurization assisted with the N2 sweep could displace the pore water rapidly.According to the results,it is recommended that using the short-term N2 sweep as an auxiliary means in the early stage of depressurization to expand the gas-phase space in order to achieve the highest production efficiency.

A significant quantitative trait locus on chromosome Z and its impact on egg production traits in seven maternal lines of meat-type chicken

Background:Egg production is economically important in the meat-type chicken industry.To better understand the molecular genetic mechanism of egg production in meat-type chicken,genetic parameter estimation,genome-wide association analyses combined with meta-analyses,Bayesian analyses,and selective sweep analyses were performed to screen single nucleotide polymorphisms(SNPs)and other genetic loci that were significantly associated with egg number traits in 11,279 chickens from seven material lines.Results:Yellow-feathered meat-type chickens laid 115 eggs at 43 weeks of age and white-feathered chickens laid 143 eggs at 60 weeks of age,with heritability ranging from 0.034–0.258.Based on meta-analyses and selective sweep analyses,one region(10.81–13.05 Mb)on chromosome Z was associated with egg number in all lines.Further analyses using the W2 line was also associated with the same region,and 29 SNPs were identified that significantly affected estimation of breeding value of egg numbers.The 29 SNPs were identified as having a significant effect on the egg number EBV in 3194 birds in line W2.There are 36 genes in the region,with glial cell derived neurotrophic factor,DAB adaptor protein 2,protein kinase AMP-activated catalytic subunit alpha 1,NAD kinase 2,mitochondrial,WD repeat domain 70,leukemia inhibitory factor receptor alpha,complement C6,and complement C7 identified as being potentially affecting to egg number.In addition,three SNPs(rs318154184,rs13769886,and rs313325646)associated with egg number were located on or near the prolactin receptor gene.Conclusion:Our study used genomic information from different chicken lines and populations to identify a genomic region(spanning 2.24 Mb)associated with egg number.Nine genes and 29 SNPs were identified as the most likely candidate genes and variations for egg production.These results contribute to the identification of candidate genes and variants for egg traits in poultry.

Immunogenetic basis of chicken’s heterophil to lymphocyte ratio revealed by genome-wide indel variants analysis

Enhancing host immunity is an effective way to reduce morbidity in chickens.Heterophil to lymphocyte ratio(H/L)is associated with host disease resistance in birds.Chickens with different H/L levels show different disease resistances.However,the utility of the H/L as an indicator of immune function needs to be further analyzed.In this study,a H/L directional breeding chicken line(Jingxing yellow chicken)was constructed,which has been bred for 12 generations.We compared the function of heterophils,and combined statistical analysis to explore the candidate genes and pathways related to H/L.The oxidative burst function of the heterophils isolated from the H/L selection line(G12)was increased(P=0.044)compared to the non-selection line(NS).The 22.44 Mb genomic regions which annotated 300 protein-coding genes were selected in the genome of G9(n=92)compared to NS(n=92)based on a genome-wide selective sweep.Several selective regions were identified containing genes like interferon induced with helicase C domain 1(IFIH1)and moesin(MSN)associated with the intracellular receptor signaling pathway,C–C motif chemokine receptor 6(CCR6),dipeptidyl peptidase 4(DPP4)and hemolytic complement(HC)associated with the negative regulation of leukocyte chemotaxis and tight junction protein 1(TJP1)associated with actin cytoskeleton organization.In addition,45 genome-wide significant indels containing 29 protein-coding genes were also identified as associated with the H/L based on genome-wide association study(GWAS).The expression of protein tyrosine phosphatase non-receptor type 5(PTPN5)(r=0.75,P=0.033)and oxysterol binding protein like 5(OSBPL5)(r=0.89,P=0.0027)were positively correlated with H/L.Compared to the high H/L group,the expressions of PTPN5 and OSBPL5 were decreased(P<0.05)in the low H/L group of Beijing you chicken.The A/A allelic frequency of indel 5_13108985(P=3.85E–06)within OSBPL5 gradually increased from the NS to G5 and G9,and the individuals with A/A exhibited lower H/L than individuals with heterozygote A/ATCT(P=4.28E–04)and homozygous ATCT/ATCT(P=3.40E–05).Above results indicated oxidative burst function of heterophils were enhanced,and 22.44 Mb genomic regions were selected with the directional selection of H/L.In addition,PTPN5 and OSBPL5 genes were identified as H/L-related candidate genes.These findings revealed the complex genetic mechanism of H/L related to immunity and will allow selection for improving chicken immunity based on the H/L.

Dynamic chromatin architectures provide insights into the genetics of cattle myogenesis

Background Sharply increased beef consumption is propelling the genetic improvement projects of beef cattle in China.Three-dimensional genome structure is confirmed to be an important layer of transcription regulation.Although genome-wide interaction data of several livestock species have already been produced,the genome structure states and its regulatory rules in cattle muscle are still limited.Results Here we present the first 3D genome data in Longissimus dorsi muscle of fetal and adult cattle(Bos taurus).We showed that compartments,topologically associating domains(TADs),and loop undergo re-organization and the structure dynamics were consistent with transcriptomic divergence during muscle development.Furthermore,we annotated cis-regulatory elements in cattle genome during myogenesis and demonstrated the enrichments of promoter and enhancer in selection sweeps.We further validated the regulatory function of one HMGA2 intronic enhancer near a strong sweep region on primary bovine myoblast proliferation.Conclusions Our data provide key insights of the regulatory function of high order chromatin structure and cattle myogenic biology,which will benefit the progress of genetic improvement of beef cattle.

Ring Oscillator for 60 Meter Bandwidth

The 60-meter band range is tremendously useful in telecommunication,military and governmental applications.The I.T.U.(International Telecommunication Union)required isolationism to former radio frequency services because the various frequency bands are extremely overloaded.The allocation of new frequency bands are a lengthy procedure as well as time taking.As a result,the researchers use bidirectional,amateur radio frequency communication for 60-meter band,usually the frequency slot of 5250-5450 KHz,although the entire band is not essentially obtainable for all countries.For transmission and reception of these frequencies,a local oscillator is used in the mixer unit to generate the local signal for mixing the input and reference signals.For this function different type of oscillators are used.In this paper,a three-stage ring oscillator is designed with 1 V supply.Ring oscillators(RO)is the base to explore like to identifying,specify with modelling resources in the disparity in behaviour of the circuit in terms of industrialized design and layout parameters.This type of oscillators are free from noise as inductor is not used to the circuit as in LC oscillator,Heartly oscillator,Colpitt and tuned oscillators.The present approach of circuit designing,the scaling of CMOS(Complementary Metal Oxide Semiconductor)transistor will moderate,the procedure variability.In the forthcoming article,a ring oscillator with fixed capacitor(1 pF)and with variable capacitors(1 to 100 pF)is analysed.The frequency analysis with different capacitor is performed.The total delay of 3-stage oscillator is 4.82 ns with 5.2 MHz oscillation frequency.The overall Power dissipation of the circuit is 1.852μWat 1 V supply.The simulation analysis is performed on 45 nm CMOS technology with both transistor width are 278 and 420 nm.