The enhancement of even-order harmonics near the cut-off of high-order harmonic spectra from monolayer MoS 2 has been experimentally observed recently by several groups. Here we demonstrate that this enhancement can be interpreted as a result of spectral interference between half-cycles with opposite polarity by adopting a fully quantum mechanical calculation. We found that, due to the energy modulation induced by Berry connections, only half-cycles with the same polarity can generate high-order harmonics near the cut-off frequency, thus the lack of destructive interference leads to the enhanced intensity of the corresponding even-order harmonics. The explanation is supported by the frequency shift of the measured harmonic peaks. Our finding revealed the role of inter-half-cycle interference in high-harmonic generation (HHG) from non-centrosymmetric materials.

We present a velocity-gauge model for the generation of even-order high harmonics, and reveal that the even-order harmonics originate from the multiple-step transitions among the energy bands in momentum space, while the odd-order harmonics are mainly from direct transitions. The lower valence band is found vital for the generation of even harmonics. Relative intensity of even-order harmonics versus the odd orders is calculated and shows a growing trend as the laser field amplitude increases.

花岗岩以其优越的力学性质在工程中被广泛利用,提出一种多级平行黏结晶体模型(Multi Pb-GBM)用以模拟类晶体花岗岩的微观结构.以平行接触模型代替传统的光滑节理模型来刻画晶体边界,将平行接触模型分为3种类型:晶体内部接触、同种矿物内部的晶体边界接触以及不同种矿物的边界接触.应用单轴压缩试验和巴西劈裂试验对模型的微观参数进行校正,开展多组数值试验研究晶体尺寸分布系数影响下脆性花岗岩试样的动态损伤破裂演化过程,并基于Fish函数建立一套完整的裂隙监测系统以记录微裂缝的行为特点.研究结果表明:(1)晶体尺寸分布系数对破裂模式会产生影响,单轴压缩试验与劈裂试验中张拉裂纹均占据主导,随着花岗岩晶体尺寸的增大,单轴抗压强度(UCS)和抗拉强度(UTS)均呈现出增大趋势.(2)不同矿物晶界处的裂纹数量多于同种矿物晶界处的裂纹数量,随着平均晶体尺寸分布系数的增大,晶界处的裂纹数量逐渐减少,内部破裂数量相对增多.(3)微裂纹首先出现在第三级接触处,随后二级接触处发生断裂,最后一级接触裂纹数目迅速增大.(4)单轴压缩试验是由钾长石-石英边界为主的晶间破裂向钾长石-斜长石为主的晶内损伤转化的过程,直至宏观破坏的发生.

倾斜矿体开采引起的地表变形与断层活化问题给矿山工程带来重大隐患,如竖井破坏.为了研究倾斜矿体采动及断层活化作用下竖井的变形破坏规律,引入一种软材料小模型物理模拟方法,对不同倾斜角度矿体、不同倾角断层下的模型进行开挖试验.结果表明:该方法能够较好地模拟典型的工程地质现象;在试验工况下,矿体倾斜角度不同,则自重应力场中的竖井受到采动影响的程度不同;处于开挖区上方的隐伏断层,倾角极缓时具有一定屏蔽垂直位移的作用,缓倾断层活化对水平位移的影响和陡倾断层活化对于垂直位移的影响具有某些相似性和对称性;倾角越接近45°,断层活化作用越强烈,对地表起伏度的影响越大,且竖井更有可能产生上部沉降、底部拱起的现象.

Several studies have simulated and studied the phenomenon of toppling failure caused by open-pit excavation. However, these studies do not involve or neglect the interpretation of some special geometric characteristics and laws of this deformation. Only by understanding the subtle geometric characteristics and geometric laws of slope toppling failure, can we understand the conditions, processes and mechanisms of such deformation. In this study, a soft material, small model, deformable element method is successfully used to simulate the phenomenon of the bending each layer element from the lower part of the slope to the upper, with the dislocation distance (scraps on the slope) being bigger. This method overcomes the shortcoming of the rigid body element that traditional methods cannot simulate. Finally, the conditions and mechanism of this phenomenon are further analysed and explained by structural unit of inclined composite cantilever and elastic theory. Under the action of the body force component f(x) which is parallel to the longitudinal direction of the cantilever, the geometric characteristics of the single cantilever in the composite cantilever are changed such that the upper part of it is narrowed and the lower part of it is widened. Under the action of the body force component f(y) which is perpendicular to the longitudinal direction of the cantilever, the cantilever is bent. Under the action of these two body force components, the composite cantilever is bent as a whole after open-pit excavation. Because of the change in the geometric shape of the cantilever, any single cantilever has a larger deflection than the other single cantilever below it; that is, greater the deflection of each cantilever along the slope upwards, greater is the curvature of the corresponding point. Finally from the lower part of the slope to the upper, the scraps on the slope are bigger.

Land subsidence in the Sanshandao area, Laizhou, Shandong Province, China, has been a consequence of underground gold mining. This paper identifies the statistically significant mining subsidence factors, which are: (1) a digital elevation model of the surface; (2) the surface slope; (3) the slope aspect; (4) the thickness of the gold deposits; and (5) the depth of the gold deposits below the ground. The vertical displacement of the GPS monitoring in the Xishan gold mine (one of the Sanshandao gold mine) was selected as the dependent variable and five mining subsidence factors as the independent variables. Subsidence modeling was carried out in geographic information systems first with the ordinary least squares (OLS) method and then with the geographically weighted regression (GWR) method. Finally, the seabed subsidence was predicted with the geographically weighted regression model for the Xinli gold mine (another of the Sanshandao gold mine), in which the gold deposits are located under the sea. The results of the GWR analysis showed a marked improvement compared to those of the OLS analysis. The R2 value of the GWR model equals 0.82, which indicates that the model captured the spatial heterogeneity of the independent variables. The accuracy of determining subsidence in the area used for validation is ± 8.5 mm with a maximum calculated subsidence of − 329.26 mm. The maximum subsidence predicted with the model for the seabed is − 63 mm with a mean subsidence of − 50 mm.

三山岛金矿新立矿区是我国唯一一座海底金属矿山,其对开采技术要求较高,大规模海底开采过程中潜存的安全问题是矿山需解决的首要问题.其中,海底第四系底部黏土隔水层和F1断层泥是阻水的关键部位,这2处隔水层破坏后有可能会造成海水溃入,因此需要探明矿区上覆岩层的地质结构,尤其是黏土隔水层分布情况.经过探索形成了高精度三维地震勘探技术,包括灵活的采集几何,低噪声接收器条件和定量控制等,并在开展新立矿区海底地震勘探中取得了很好的效果.研究表明:在矿区地质勘查中,三维地震勘探方法可在较大深度范围内精细探测浅层与深部的地质结构形态,是一种有效且实用的技术方法;第四系在探测区稳定分布,埋深在8～39m之间,主要表现为西部和北部偏薄,南东方向地层逐渐变深,其中第四系底部的黏土隔水层厚度变化范围为1～11m,分布趋势与第四系基本一致,但在F1断裂附近明显变薄,厚度为2.5～5.0 m,并向北西方向逐渐变薄,隔水稳定性变差,对矿床开采具有一定的风险;下覆基岩强、中、弱3层风化带总的厚度变化范围为3～35m,在F1断裂附近风化带明显变厚,厚度为20～35 m,是矿区主要的透水结构.高精度三维地震技术首次应用于新立矿区的地质结构探测中,为三山岛金矿海底矿区的安全开采设计提供了数据支持.

Submarine mine water inrush has become a problem that must be urgently solved in coastal gold mining operations in Shandong, China. Research on water in subway systems introduced classifications for the types of mine groundwater and then established the functions used to identify each type of water sample. We analyzed 31 water samples from −375 m underground using multivariate statistical analysis methods. Cluster analysis combined with principle component analysis and factor analysis divided water samples into two types, with one type being near the F3 fault. Principal component analysis identified four principle components accounting for 91.79% of the total variation. These four principle components represented almost all the information about the water samples, which were then used as clustering variables. A Bayes model created by discriminant analysis demonstrated that water samples could also be divided into two types, which was consistent with the cluster analysis result. The type of water samples could be determined by placing Na+ and CHO3− concentrations of water samples into Bayes functions. The results demonstrated that F3, which is a regional fault and runs across the whole Xishan gold mine, may be the potential channel for water inrush, providing valuable information for predicting the possibility of water inrush and thus reducing the costs of the mining operation.

三山岛金矿新立矿区是我国唯一一座海底金属矿山,其对开采技术的要求较高,海下开采遇到了严重的安全问题,其中海底移动变形对采矿安全造成重大威胁.金属矿开采所引起的覆岩移动和变形是一个复杂的力学问题,掌握采空区覆岩体采动岩体移动规律和实现对覆岩沉陷的有效预测是新立矿区亟待解决的重要课题.通过对新立矿区井下55线各中段石门巷道顸板位移进行监测,得到了充填法开采倾斜金属矿体的覆岩移动和变形特征.在此基础上,提出了倾斜金属矿体充填采矿法引发覆岩内部移动和变形的悬臂梁机制.最后,通过分析顶板位移监测数据和位移曲线特征,提出了倾斜矿体充填法开采覆岩沉陷预测的轮廓函数方法.该方法由几个指数函数组成,采用该方法得到的沉陷预测曲线与实测结果十分接近,预测准确率都在85％以上.该研究结果对海底矿山的安全生产具有重要的指导意义.

Cracks are critical for the deformation and failure of rock masses, but the effects of real cracks are rarely considered when evaluating the stability and safety of practical engineering. This paper presents a study on the application of fractures in the Sanshandao Gold Mine. Field investigation and statistical analysis methods were adopted to obtain the distribution laws of the cracks. Laboratory tests, MATLAB programming, and simulation using the software, GDEM (Gdem Technology, Beijing, China, Co., Ltd.), were employed to study the mechanical behaviors of rock masses with real fractures after excavation. The main results are as follows: (1) Three sets of highly discrete cracks were developed in the study area. Their inclination and dip can be approximately considered to follow a Gaussian distribution or uniform distribution. They had close ties to the three faults developed in the mining area. (2) Compared with the model that did not consider cracks and the model processed by the equivalence idea, the surrounding rock deformation caused by excavation of the model that considered real cracks was larger than that of the former and smaller than that of the latter. However, its influence range was larger than that of the other two models. The results show that it is reasonable to use three sets of discrete cracks to characterize the fracture distribution of the surrounding rock. In the evaluation of roadway stability, it is not advisable to use the equivalence method to deal with all the cracks. Considering a part of the cracks that are compatible with the size of the calculation model, a relatively accurate evaluation can be obtained in terms of the deformation, failure, and permeability changes of the surrounding rock.

This paper is based on the observation and the analysis of the geological phenomena of the rock mass in engineering states.It has studied and summarized some results of physical and numerical models and developed the 12 kinds of qualitative effects of the discontinuities on the mechanical behavior and actions,and then explained and discussed them respectively.

构建含有埃博拉出血热病毒(Ebola hemorrhagic fever virus,EHFV)小片段分泌蛋白S基因、马尔堡出血热病毒(Marburg hemorrhagic fever virus,MHFV)GP基因、辛诺柏病毒(Sin Nombre virus,SNV)G2糖蛋白基因及非洲欧尼恩病毒(Africa O'nyong nyong virus,O’NNV)E2蛋白基因的重组痘苗病毒.设计含EGFP筛选标记和4种外源基因的穿梭质粒,并利用同源重组技术、荧光筛选技术和Cre/LoxP敲除系统,最终获得四联重组痘苗病毒.使用PCR方法鉴定重组痘苗病毒及其遗传稳定性;用透射电镜观察病毒形态.结果显示:所构建的多联重组痘苗病毒rVTT-J-4+具有良好的遗传稳定性,并且具备痘苗病毒的完整形态.结果表明:成功构建了含有4种外源基因的重组痘苗病毒rVTT-J-4,为后续多联疫苗的研究奠定了基础.

为建立可同时检测新疆出血热病毒(CCHFV)、裂谷热病毒(RVFV)、拉沙病毒(LSV)的荧光基因芯片,分剐针对CCHFV和RVFV的S基因、LSV的NP基因,应用生物学软件设计了3对引物与6条探针.运用多重PCR扩增和标记目的片段,将其与基因芯片杂交,最后扫描分析结果.分别对杂交温度与杂交时间进行条件优化,最后对基因芯片的特异性、敏感性和重复性进行评估.结果显示,设计的所有探针都可以与目的片段特异性杂交,探针1a与1b可检测到CCHFV,探针2a与2b可检测到RVFV,探针3a与3b可检测到LSV.相比多重PCR,荧光基因芯片检测CCHFV的灵敏度提高了10倍,检测RVFV的灵敏度提高了100倍,检测LSV的灵敏度提高了100倍.结果表明,本试验建立的同时检测3种出血热病毒的荧光基因芯片检测方法特异性高、敏感性强,可用于这3种病毒的快速检测与甄别.

Based on GPS monitoring data, the movement and deformation rules of surrounding rock of open pit in the Longshou Mine of Jinchuan Company have been analyzed. The monitoring results show that underground mining has caused rock mass movement and large-range deformation, with two subsiding troughs separated by a central uplifting zone formed on the surface.The maximum settlement of the hang-ing wall sink area and footwall sink area are 767 mm and 1 078 mm respectively as well as the maxi-mum uplift amount of the rising area in the open pit bottom are 648 mm. And physical simulation ex-periment has been conducted to simulate the movement and deformation process of surrounding rock mass of open pit from open-pit mining to underground mining. The experimental results are consistent with the monitoring results.And the uplift phenomenon of the bottom of open pit in both open-pit mining and underground mining stages has been clearly observed.Moreover, the uplifting mechanism of the open pit bottom after the transformation from open-pit mining to underground mining has been theoretically analyzed, from which a conclusion has been drawn that the earlier movement and defor-mation of slope rock mass caused by open-pit mining would be activated again by the underground mining activities. And when the uplifting amount of the open pit bottom caused by the activation is larger than its settlement caused by underground mining, the open pit bottom will rise because of the extrusion.

以2001年和2013年2期Landsat影像为数据源,采用ENVI的监督分类和分类后处理功能,并结合土地利用动态度分析模型和转移矩阵分析法,对日照市的主要土地利用类型数量变化特征、土地利用动态度和土地利用类型之间的转移特征进行了研究.结果表明,在2001-2013年,日照市的土地利用类型发生了显著变化,主要表现在耕地、林地、建筑用地和未利用地等方面.其中,耕地面积减少446.08 km2,年变化率为-2.22％,主要转化为建筑用地和未利用地;林地面积减少192.55 km2,年变化率为-2.43％,主要用于建筑用地和耕地,也有部分被转化成未利用地;建筑用地呈现持续增加的态势,2001-2013年,建筑用地面积增加一倍多,年变化率为8.05％,主要来自于未利用地和耕地;未利用地面积减少265.69 km2,年变化率为-1.16％,主要被用于建筑用地.最后分析了引起土地利用变化的主要驱动因子,认为主要驱动因子是城市化进程、社会经济的发展、人口增长和人类活动.研究成果可为区域土地持续利用提供决策依据.

Using RT‐PCR method ,E0 gene of six CSFV strains were amplified ,cloned and sequenced . Then the sequences were analyzed and compared with the same gene sequences of HCLV strain ,Shimen strain ,Paderborn strain and GXWZ02 strain by DNAstar software . The nucleotide homologies were 80 .8%‐81 .5% ,82 .8%‐83 .3% ,93 .1%‐94 .2% and 93 .7%‐94 .2% , respectively , and amino acid w ere 88 .3%‐89 .7% ,89 .7%‐91 .1% ,96 .2%‐97 .7% and 97 .7%‐99 .1% with reference stains .The phylogenet‐ic analysis showed that GX strains and other 14 strains were classified as 2 groups ,while all the GX strains belonged to genotype Ⅱ .The study successfully sequenced the E0 gene of six CSFV strains in Guangxi . The results revealed that there is no large variation in Guangxi pandemic strains in recent years ,but a trend that virus development is far away from vaccine strain .

To construct American serotype porcine reproductive and respiratory syndrome virus(PRRSV)vaccine containing glycosylated protein GP5 antigenic epitope,hepatitis B virus core protein(HBc)particle was used as a vector.The codons of HBc sequence were optimized and cloned into the pET-28a(+)to gain plasmid pEO-NEW.The GP5 gene was inserted into the major immunodominant region of HBc to gain recombinant expression plasmid pEO-LEORF5.It was transformed into Escherichia coli BL21(DE3)for expression under induction of IPTG at 22 ℃.SDS-PAGE,Western-blot and the transmission electron microscope were utilized to analyze the character and structure of the recombinant protein.After ultrasonic broken,fusion protein was purified by sucrose gradient centrifugation.The results showed that the recombinant expression plasmid pEO-LEORF5 was constructed correctly.The expressed fusion protein,with a molecular mass of about 32 ku,existed in both soluble and inclusion body forms.After purification,the fusion protein reached a purity of 67% and could be assembled automatically into virus-like particles(VLPs).The constructed HBc-GP5 VLPs candidate vaccine provided a new way of developing the PRRS vaccine.

为了构建并筛选表达新城疫病毒(NDV)F蛋白的重组鸡痘病毒(rFPV-F),通过PCR扩增F基因,克隆至pMD18-T Simple载体,进行DNA序列分析和遗传进化关系分析.将测序正确的F基因克隆至笔者所在实验室自行构建的新型鸡痘病毒穿梭载体pTS2GFPV150中,获得重组质粒pTS2GFPV150-F.然后将其与鸡痘病毒FPV282E4株共转染鸡胚成纤维细胞进行同源重组,挑取表达增强型绿色荧光蛋白的噬斑,经多轮筛选获得重组病毒rFPV-F,应用PCR、RT-PCR、Western-blot等方法对重组鸡痘病毒进行鉴定.结果显示,成功获得NDV F基因及重组F基因的鸡痘病毒rFPV-F,并证实F基因已被整合到鸡痘病毒基因组中,且在感染细胞内被成功表达.本研究成功获得了1株表达NDV F基因的重组鸡痘病毒,为下一步开展动物体内免疫研究奠定了基础.

[目的]了解广西地区流行猪瘟病毒(CSFV)E2基因的变异规律与趋势,及其与疫苗毒株基因的差异性,为制定猪瘟防控措施提供科学依据.[方法]对广西地区流行CSFV毒株的E2基因进行克隆及序列测定,并与兔化弱毒(HCLV)、石门(Shimen)毒株的E2基因进行同源性比对分析,绘制遗传进化树.[结果]广西地区流行CSFV毒株与 HCLV株、Shimen株的核苷酸序列同源性为81.9％～83.3％和81.1％～82.4％,推导氨基酸序列同源性为89.3％～90.6％和87.9％～89.5％;不同广西地区流行毒株间的核苷酸序列及其推导氨基酸序列同源性分别为90.8％～99.5％和94.1％～99.5％,且均属于S2基因群的S2.1亚群,其中广西玉林株GXYL1、GXYL2、GXYL3、GXYL4、GXYL5均属于S2.1b子群,而广西贺州株GXHZ1、GXHZ2与广西北海株GXBH1、GXBH2株属于S2.1c子群.与HCLV株、Shimen株的E2基因编码氨基酸序列相比,9株广西地区流行CSFV毒株共有49处氨基酸发生变异,其中与抗原特性有关的变异有5处,分别为G713E、T724Y、E727H、I732S和S734R位点.[结论]广西地区流行CSFV毒株随时间推移的变异不明显,但其遗传变异总趋势朝着偏离疫苗株的方向发展.