Interacting topological magnons in a checkerboard ferromagnet

This work is devoted to studying the magnon-magnon interaction effect in a two-dimensional checkerboard ferromagnet with the Dzyaloshinskii-Moriya interaction.Using a first-order Green function method,we analyze the influence of magnon-magnon interaction on the magnon band topology.We find that Chern numbers of two renormalized magnon bands are different above and below the critical temperature,which means that the magnon band gap-closing phenomenon is an indicator for one topological phase transition of the checkerboard ferromagnet.Our results show that the checkerboard ferromagnet possesses two topological phases,and its topological phase can be controlled either via the temperature or the applied magnetic field due to magnon-magnon interactions.Interestingly,it is found that the topological phase transition can occur twice with the increase in the temperature,which is different from the results of the honeycomb ferromagnet.

R^n上的基于Checkerboard格点的不可分双正交小波

研究了一类基于Checkerboard格点的不可分双正交小波,并证明了其尺度函数逼近阶与光滑性的上界.在此基础上提出了此类小波的构造算法.理论分析表明,使用该算法构造的小波具有很好的对称性、光滑性以及对多维信号采样的视觉优势.此外该算法能够构造具有任意给定消失矩的小波,并且其小波滤波器具有有理系数,这在多维信号处理中具有重要意义.实例分析也验证了构造算法的有效性和上述结论.

Checkerboard法对ε-聚赖氨酸和壳聚糖抑菌作用的研究

该研究以大肠杆菌和金黄色葡萄球菌为指示菌,探究ε-聚赖氨酸和壳聚糖复配溶液的抑菌效果。结果表明:6μg/mLε-聚赖氨酸和100μg/mL壳聚糖复配溶液对大肠杆菌的抑制作用最佳;16μg/mLε-聚赖氨酸和100μg/mL壳聚糖复配溶液对金黄色葡萄球菌的抑制作用最佳。Checkerboard法表明壳聚糖和ε-聚赖氨酸抑菌作用具有叠加效应。ε-聚赖氨酸与壳聚糖复配溶液处理能够使细菌出现蛋白质泄漏现象。

Automatic three-dimensional reconstruction based on four-view stereo vision using checkerboard pattern

An automatic three-dimensional(3D) reconstruction method based on four-view stereo vision using checkerboard pattern is presented. Mismatches easily exist in traditional binocular stereo matching due to the repeatable or similar features of binocular images. In order to reduce the probability of mismatching and improve the measure precision, a four-camera measurement system which can add extra matching constraints and offer multiple measurements is applied in this work. Moreover, a series of different checkerboard patterns are projected onto the object to obtain dense feature points and remove mismatched points. Finally, the 3D model is generated by performing Delaunay triangulation and texture mapping on the point cloud obtained by four-view matching. This method was tested on the 3D reconstruction of a terracotta soldier sculpture and the Buddhas in the Mogao Grottoes. Their point clouds without mismatched points were obtained and less processing time was consumed in most cases relative to binocular matching. These good reconstructed models show the effectiveness of the method.

Sand-fixing characteristics of Carex brunnescens and its application with straw checkerboard technique in restoration of degraded alpine meadows

Carex brunnescens（Pers.）, a typical clonal species, is considered to be the only herb found to date that can develop on sand dunes in Maqu alpine region of northwestern China. However, the characteristics that C. brunnescens resists to harsh alpine environment have not been documented. In this study, we conducted a field investigation to determine the morphological, reproductive, and sand-fixing characteristics of C. brunnescens. Concomitantly, we transplanted the belowground rhizomes of C. brunnescens to sand dunes and compared the abilities to restore degraded alpine meadows among sand dunes that had no further treatment（SD＋N）, sand dunes that had straw checkerboard technique but no transplanted rhizomes of C. brunnescens（SD＋SCT）, and sand dunes that had both SCT and transplanted rhizomes of C. brunnescens（SD＋SCT＋P）. We found that belowground vertical rhizomes and horizontal rhizomes（including branching rhizomes and main rhizomes） of C. brunnescens were highly developed and that population reproduction was dominated by horizontal rhizomes. C. brunnescens exhibited a significant sand-fixation effect under following conditions： population density was 145–156 ramets/m^2, vegetation cover was 31.2%–39.3%, total length of belowground rhizomes was 11,223 cm/m^2, total length of belowground first-order roots was 9161–10,524 cm/m^2, fresh weight of aboveground part was 198.5–212.6 g/m^2, and fresh weight of belowground part was 578.8–612.4 g/m^2. It should be particularly noted that SD＋SCT＋P treatment（sand dunes that had both straw checkerboard technique and transplanted rhizomes of C. brunnescens） was the best and SD＋N（sand dunes that had no further treatment） was the worst in terms of following biotic indicators： total number of reproductive ramets, total number of belowground rhizomes, and fresh weight of aboveground and belowground parts of C. brunnescens, contents of soil organic carbon, available nitrogen, microbial biomass carbon, and microbial biomass nitrogen. It implies that applying SCT in sand dunes and transplanting belowground rhizomes to sand dunes with SCT could improve both soil fertility and growth of C. brunnescens. These results suggest that the SCT-promoted high reproductive abilities of belowground rhizomes of C. brunnescens can successfully facilitate the establishment of ramets and can thus be an effective strategy to restore degraded vegetation in Maqu alpine region of northwestern China.

Hubbard model on an anisotropic checkerboard lattice at finite temperatures: Magnetic and metal–insulator transitions

We study magnetic and Mott transitions of the Hubbard model on the geometrically frustrated anisotropic checkerboard lattice at half filling using cellular dynamical mean-field theory. Phase diagrams over a wide area of the parameter space are obtained by varying the interparticle interaction strength, geometric frustration strength, and temperature. Our results show that frustration and thermal fluctuations play a competing role against the interactions and in general favor a metallic phase without antiferromagnetic order. Due to their interplay, the system exhibits competition between antiferromagnetic insulator, antiferromagnetic metal, paramagnetic insulator, and paramagnetic metal phases in the intermediateinteraction regime. In the strong-interaction limit, which reduces to the Heisenberg model, our result is consistent with previous studies.

Dynamics analysis on transverse cutting mechanism of straw checkerboard paving robot

The transverse cutting mechanism of the checkerboard paving robot, which directly affects the robot＇s operation, is regarded as the most important part in a transverse pavement system This research aims at designing a new system which is appropriate for desert wofidng en- vironments and finishing cutting the rope of straw. In this paper, computer emulating technology is applied, and with three-dimensional modeling by Pro/ENGINEER software, can observe whether or not interference exists. Also, the speed and displacement parameters of the main parts of the cutting system are given by the dynamic emulation by Automatic Dynamic Analysis of Mechanical System （ADAMS）, which theoretically assures the feasibility and appropriateness of the cutting mechanisrn~ Finally, results of the experinaent shows that the cutting mechanism can cut the straw strand as designed.

Wideband radar cross-section reduction using plasma-based checkerboard metasurface

For stealth technology,in order to overcome the limitations of thin-layer plasma for electromagnetic waves attenuation and further broaden the radar cross-section(RCS)reduction(RCSR)band of the metasurface,the plasma-based checkerboard metasurface composed of plasma and checkerboard metasurface is investigated to achieve better RCSR.We designed a checkerboard metasurface which can achieve abnormal reflection to reduce RCS and whose-10d B RCSR bandwidth is from 8.1 to 14.5 GHz,the RCSR principle of it lies in the backscattering cancellation,which depends on the phase difference of artificial magnetic conductor(AMC)units.The designed plasma-based checkerboard metasurface is a thin composite structure,including a checkerboard metasurface,a plasma layer,and an air gap which is between them.Full wave simulations confirm that the plasma-based checkerboard metasurface’s–10 dB RCS reduction bandwidth and RCS reduction amplitude,are both increased under different polarized waves compared with the only single plasma or the only metasurface.We also introduced the reason and mechanism of the interaction between plasma and the checkerboard metasurface to improve the RCSR effect in detail.As plasma-based checkerboard metasurface does not need the plasma to be too thick for plasma stealth,its application in practical scenarios is easier to implement.

Checkerboard DNA-DNA杂交技术用于G^+致龋菌的分析

Checkerboard DNA-DNA杂交技术(CKB)能利用地高辛(DIG)标记的基因组DNA探针对菌斑样品中的40个菌种同时进行定量分析。此技术最初用于研究龈下菌斑的优势G-菌。本研究的目的是进一步发展此项技术,并把它应用于一个更大范围的潜在致龋菌G+菌和白色念珠菌的分析。

Bose-Hubbard Model in Checkerboard Superlattices with a Magnetic Field

在这份报纸，我们调查古典并且 BoseHubbard 的量阶段转变在吝啬地的水平与一个磁场在棋盘超点阵当模特儿。由分析正常状态的稳定性，阶段边界是为零的获得的经分解，没有磁场，在一个统一理论框架并且容易的有限温度延长到状况。所有结果说明磁场的介绍提高正常状态和莫特绝缘体的稳定性。另外，我们也注意批评跳跃术语介绍相反地跟随霍夫施塔特蝴蝶的上面的边界的震荡的行为。

Hofstadter's Butterfly and Phase Transition of Checkerboard Superconducting Network in a Magnetic Field

我们学习棋盘的磁性的效果超导的电线网络。基于 de GennesAlexader 理论，我们在电线网络为超导的顺序参数获得差别方程。通过解决这些差别方程，我们获得特征值，连接了到连贯长度，，磁场的功能。特征值的图显示出分数维的结构，是所谓的霍夫施塔特的蝴蝶。我们也计算并且讨论棋盘的转变温度的依赖超导的电线在应用磁场上联网，它与霍夫施塔特的蝴蝶光谱的起来边有关。

耐碳青霉烯类鲍曼不动杆菌联合药敏试验研究

目的了解耐碳青霉烯类鲍曼不动杆菌(CRAB)的分布特征和耐药状况,评价以黏菌素(COL)为基础,分别与头孢哌酮/舒巴坦(SCF)、替加环素(TGC)、亚胺培南(IPM)、美罗培南(MEM)、阿米卡星(AK)和左氧氟沙星(LEV)联合的体外抗菌效果,为临床抗感染治疗提供参考。方法收集2022年我院75株非重复分离的CRAB菌株,用WHONET 5.6软件分析其临床分布和耐药情况。从中筛选25株,采用微量肉汤稀释法测定各药物单独及联合时的最低抑菌浓度(MIC),用棋盘法抑菌试验计算部分抑菌浓度指数(FIC)判定联合效应。结果2022年我院共分离鲍曼不动杆菌145株,其中CRAB 75株,检出率51.7%。CRAB在>70岁老年患者中检出率最高(40.0%),主要来源于血液(41.3%)和痰液(37.3%)标本,ICU是主要分离科室。75株CRAB对5种抗菌药物哌拉西林(PRL)、哌拉西林/他唑巴坦(TZP)、头孢曲松(CRO)、IPM和MEM均100%耐药;对3种药物氨苄西林/舒巴坦(SAM)、头孢吡肟(FEP)和复方磺胺甲噁唑(SXT)的耐药率均>95%;对LEV、SCF、AK、TGC和COL的耐药率分别为86.7%、82.7%、77.4%、2.4%和0.0%。25株CRAB的联合药敏试验显示,COL分别与SCF和TGC的协同率最高(92%和80%),协同率与相加率之和均为100%;COL与IPM、MEM、AK、LEV联合的协同率依次为64%、72%、56%和48%,均无拮抗作用。结论CRAB呈高度耐药,老年和ICU患者是高危人群。COL与SCF联合具有最佳协同作用,COL与LEV联合效果最差,值得临床参考。

The Compressibility of Checkerboard Surfaces of Link Diagrams

Consider the checkerboard surfaces defined by some link diagrams. When they are not orientable, one considers the boundary surfaces of small regular neighborhoods of them. This article studies the compressibility problem of these kinds of surfaces in the link complements. The problem is solved by devising a normalization theory for the compressing discs, which brings up an algorithm to read out compressibility directly from the link diagrams. As an application of the algorithm, the compressibility changes under Reidermeister moves are studied. Diagrams from the knot tables are also studied, and surprisingly, some of them are shown to define completely compressible surfaces of this kind. Infinitely many examples of non-alternating knot diagrams with incompressible surfaces of this kind are also constructed.

Checkerboard Colourable Twuals

In this article we show that any embedded graph has a checkerboard colourable twual,which is equivalent to having a bipartite twual.We also obtain that any Eulerian embedded graph has a checkerboard colourable partial Petrial,answering questions posed by Ellis-Monaghan and Moffatt[Trans.Amer.Math.Soc.,364,1529–1569(2012)].

抗菌药物体外联合药物敏感性试验方法

近年来,多重耐药菌(MDR)日益流行,但相关治疗方法有限,抗菌药物相互作用相关研究成为热点。体外联合药物敏感性试验可以判断2种及以上抗菌药物是否有协同作用,为临床联合使用抗菌药物提供参考。目前,临床常用体外联合药物敏感性试验方法有时间-杀菌曲线(TKA)、棋盘稀释法(CB)、E试验和纸片法。文章就上述方法进行综述,为临床应用提供参考。

基于控制点排序的透视变换原木截面测量方法

木材被盗案件中,需要先找到被盗的可疑树木,然后和留在地面的基部伐桩进行比对,确认可疑树木为被盗树木。为了辅助公安机关判断可疑木材是否为被盗木材,需要精确测量被盗木材的基部伐桩和可疑木材的截面大小等特征。首先对留在地面的基部伐桩进行拍照,并对找到的可疑木材截面进行拍照,然后比对2个截面的相似性,从而判断可疑木材是否属于被盗木材。由于被盗木材一般数量庞大,摄像机拍照存在畸变,拍照的姿态、角度和焦距以及环境光照都对成像有具体影响,因此,提出采用矩形棋盘格和最小二乘透视变换的方法,将所有的棋盘格角点作为控制点,并根据透视变换的直线特征不变性,构建了一种基于Hough变换的控制点排序方法。该方法能够将不同角度、不同姿态拍摄的图像变换到鸟瞰图像,并缩放到原始尺寸,从而进行测量。对于不同角度、不同姿态、不同焦距、不同光照条件下的图像,本研究提出的透视变换方法均可以把特征棋盘格及棋盘格后面的伐桩图像校正到图像的中间位置,得到伐桩的鸟瞰图,精确地复原伐桩的原貌。对校正后的图像采用MATLAB的imtool工具进行测量,测量结果表明,该方法测量误差最大为2.45%,能满足公安机关对可疑木材是否为被盗木材的辅助判断需求。

11种联合方案对耐碳青霉烯类肠杆菌的体外联合药敏试验

目的 观察头孢他啶/阿维巴坦(CZA)联合氨曲南(ATM),亚胺培南(IPM)、美罗培南(MEM)分别联合头孢他啶(CAZ)、头孢哌酮/舒巴坦(SCF)、阿米卡星(AK)、左氧氟沙星(LEV)和磷霉素(FOS)对产KPC、NDM和IMP的耐碳青霉烯类肠杆菌(CRE)的体外联合药物敏感性。方法 选取从临床标本中分离的38株非重复CRE,采用微量肉汤稀释法测定抗菌药物对菌株的最低抑菌浓度(MIC),棋盘稀释法进行联合药敏试验,计算部分抑菌浓度指数(FIC)判定联合效果。结果 CZA对22株产KPC菌株的MIC均≤4μg/mL,对16株产B类金属酶NDM、IMP菌株的MIC均>128μg/mL,联合ATM后协同率为100%;IPM与MEM分别联合SCF协同率最强,分别为63.2%、68.4%,协同率与相加率之和为100%,IPM联合FOS的协同率与相加率之和最低,为40.5%。在肺炎克雷伯菌(KP)中,IPM与MEM联合SCF协同率均为68%,协同率与相加率之和均为100%,IPM联合FOS的协同率与相加率之和最低,为24%;大肠埃希菌(ECO)中,IPM与MEM联合SCF协同率分别为44.4%、77.8%,协同率与相加率之和为100%,IPM联合FOS的协同率与相加率之和最低,为66.7%。基因型KPC菌株中,IPM与MEM联合SCF协同率分别为72.7%、63.6%,协同率与相加率之和均为100%,IPM联合FOS的协同率与相加率之和最低,为22.7%;基因型NDM菌株中,IPM与MEM联合SCF协同率分别为46.7%、80.0%,协同率与相加率之和为100%,IPM联合FOS的协同率与相加率之和最低,为64.3%。所有联合方案均无拮抗作用。结论 CZA单独或联合ATM对CRE菌株有效。IPM与MEM分别联合其他抗菌药物中,IPM与MEM联合SCF的协同率与相加率之和最高,IPM联合FOS的协同率与相加率之和最低。不是所有联合方案都有效,同一菌株不同联合方案的效果不同,同一联合方案对不同菌株效果也不同,两药间的剂量配比也很重要。

煤矿井下自动加卸钻杆靶标图像清晰化方法研究

受煤矿井运输巷道空间限制,将钻孔机器人设计为灵活布局的钻进和钻杆加卸2个独立系统,利用基于合作靶标的单目视觉识别,将钻进和钻杆加卸2个系统关联,解决两系统递送钻杆的协同作业问题。然而,煤矿井下钻孔施工中场景复杂,存在孔口煤渣、污水污染合作靶标、粉尘浓度大能见度低、人造光源亮度低、光照不均匀使靶标图像对比度低,以及矿灯直射合作靶标反光等问题,会影响合作靶标图像清晰度,使基于靶标识别加卸钻杆的位置的精度降低,进而影响钻孔机器人自动加卸钻杆的成功率。因此,首先针对施工中孔口返出的煤渣、煤泥污染合作靶标的问题,利用形态学滤波中先腐蚀,再膨胀的开运算,清除煤渣间断斑块和突出靶标像素点;先膨胀再腐蚀的闭运算,消除小的孔洞和间断细小鸿沟,达到消除固体污染物对合作靶标的影响;其次针对粉尘、岩尘、水雾和污水影响图像对比度问题,通过暗通道先验求出初始透射率,采用梯度域导向滤波精细化透射率,利用导向滤波得到改进暗通道,并求大气光值,利用大气散射模型得到除雾后的图像,实现清晰化图像、增强图像对比度目的;最后对亚像素级角点和方向进行精细化,优化能量函数,使用种子棋盘格沿4个边缘生长棋盘格,用能量变化情况确认是否生长出最大的棋盘,补全因强光反射缺失的合作靶标图像。实验结果表明:将形态学滤波、去雾算法和棋盘格生长等方法相融合,可增强煤矿井下复杂场景钻孔施工中合作靶标图像的清晰度,提高基于视觉识别的图像精度,为钻孔机器人自动加卸钻杆的精确控制奠定基础。

药食同源中药联合抑菌作用及抑菌喷雾剂的研制

探讨7味药食同源中药水提取物及其联用对大肠杆菌、金黄色葡萄球菌、白色念珠菌的体外抑菌效果,并将其应用于抑菌喷雾剂。采用水提法提取药液,用纸片扩散法测得单药最低抑菌浓度(MIC)及最小杀菌浓度(MBC),同时以“棋盘法+中药互配”筛选对上述致病菌具有较强协同抑制作用的药物组合,并确定适宜的药物配伍制备抑菌喷雾剂。结果显示,7味药食同源中药对3种供试病原菌均具有不同程度的抑菌效果,五味子、金银花、牡丹皮、肉桂、白芍和山楂的抑菌作用较强,其对大肠杆菌的抑菌圈直径为12.50~26.50 mm,最低抑菌浓度(MIC)<250.00 mg/mL,最小杀菌浓度(MBC)<500.00 mg/mL;其中,五味子的抑菌作用最显著,对大肠杆菌、金黄色葡萄球菌、白色念珠菌的MIC分别为31.25 mg/mL、15.62 mg/mL、250.00 mg/mL。互配试验结果表明,10种不同的药物组合对3种供试菌的联合抑菌作用各不相同,牡丹皮和肉桂的配伍组合对大肠杆菌以及肉桂和五味子的配伍组合对金黄色葡萄球菌的联合抑菌指数(FICI)均≤0.50,表现为协同作用,其中肉桂和白芍、牡丹皮和白芍的配伍组合对致病菌也有协同或相加作用。因此,选择牡丹皮、肉桂、五味子、白芍4味药食同源中药制备抑菌喷雾剂。同时初步确定药食同源中药抑菌喷雾制剂的制备工艺流程为在40℃水浴中,向中药提取液中依次搅拌加入0.2%苯甲酸、1.0%吐温-80和5.0%1,2-丙二醇。多种药食同源中药具有抗菌作用,且合理的配伍可以产生协同增效的效果,为无毒副作用抗菌喷雾剂的开发奠定了基础。

纱网沙障对风蚀坑积沙区土壤种子库的影响

以浑善达克沙地固定沙丘风蚀坑积沙区为研究对象,依据固定沙丘活化形成风蚀坑积沙区的特点铺设纱网沙障,积沙区不同铺设方式下设计4 m×4 m网格沙障(S1)和4 m带状沙障(S2);积沙区不同空间位置下使用4 m×4 m网格沙障铺设积沙区前段(L1)、积沙区中段(L2)和积沙区后段(L3)3个空间部位;以流动沙地为对照(CK),采用野外取样和温室内萌发的方法,探讨纱网沙障在积沙区不同铺设方式下及不同空间位置下对土壤种子库的影响。结果表明,1)不同处理下土壤种子库物种组成及种子密度不同,同一物种在不同处理的土壤种子库中出现时种子密度也存在差异;禾本科、藜科、菊科植物种在土壤种子库中出现比例均较高,分别占31.3%、25.0%和18.8%,占总物种数的75.0%;败酱科、豆科、毛茛科、唇形科、苋科在土壤种子库中均有出现。不同处理间S1物种种类最多,达12种,CK种类最少,仅有5种。2)风蚀坑积沙区经纱网沙障治理后,土壤种子库中植物物种数、种子密度和物种多样性均呈增加趋势;不同铺设方式下S1处理及不同空间位置下L2处理的1年生植物和多年生植物种子数均为最高。3)土壤种子库中Shannon-Wiener指数、Simpsin指数、Pielou均匀度指数和Margalef丰富度指数在不同空间位置下均表现为L2>L1>L3>CK;在不同铺设方式下均表现S1>S2>CK(Pielou均匀度指数除外)。此外,经过治理后,土壤种子库的恢复成效与沙化草地相近,与CK显著不同。设置纱网沙障改善了风蚀坑流动沙地土壤种子库结构,对快速恢复植被,促进流动沙地植被演替具有重要作用。