Topological properties of non-Hermitian Creutz ladders

We study topological properties of the one-dimensional Creutz ladder model with different non-Hermitian asymmetric hoppings and on-site imaginary potentials,and obtain phase diagrams regarding the presence and absence of an energy gap and in-gap edge modes.The non-Hermitian skin effect(NHSE),which is known to break the bulk-boundary correspondence(BBC),emerges in the system only when the non-Hermiticity induces certain unbalanced non-reciprocity along the ladder.The topological properties of the model are found to be more sophisticated than that of its Hermitian counterpart,whether with or without the NHSE.In one scenario without the NHSE,the topological winding is found to exist in a two-dimensional plane embedded in a four-dimensional space of the complex Hamiltonian vector.The NHSE itself also possesses some unusual behaviors in this system,including a high spectral winding without the presence of long-range hoppings,and a competition between two types of the NHSE,with the same and opposite inverse localization lengths for the two bands,respectively.Furthermore,it is found that the NHSE in this model does not always break the conventional BBC,which is also associated with whether the band gap closes at exceptional points under the periodic boundary condition.

Genus Distributions of M(o|¨)bius Ladders

The genus distribution of a graph is a polynomial whose coefficients are the partition of the number of embeddings with respect to the genera. In this paper, the genus distribution of Mobius ladders is provided which is an infinite class of 3-connected simple graphs.

Magnetic Long-Range Order and Colossal Magnetoresistance Effect in Double Exchange Ladders

By applying Bogoliubov's ineguality to double-exchange(DE) ladders, we show that the ferromagnetic(FM) order is absent in the new DE systems at finite temperatures. The incorporation of Jahn-Teller electron-phonon coupling, orbital degeneracy and on-site Coulomb interaction with the DE interaction do not preserve these orders. The long-wavelength thermal fluctuations of the spins oversome the DEFM correlation and destroy the FM orders. The implication of the absence of FM order on the transport of the DE ladders is discussed.

A Novel 3D Supramolecular Network Constructed from [Cu(4,4'-bipyridine)(O_2CMe)_2]_2 Molecular Ladders by Hydrogen Bonding

The title complex, {[Cu2（4,4＇-bipyridine）2（μ-O2CMe）2（O2CMe）2],H2O}n 1, was synthesized and structurally characterized by X-ray crystallography. It crystallizes in monoclinic, space group C2/c with a = 13.4474（5）, b = 11.7566（2）, c = 19.5380（6）A, β = 92.930（2）°, V = 3084.84（16） A^3, Z = 4, Cu2C28N409H30, Mr = 693.64, Dc = 1.494 g/cm^3, F（000） = 1424 and μ（MoKα） = 1.436 mm^-1. With the use of 2062 observed reflections （I 〉 2σ（I））, the structure was refined to R = 0.0769 and wR = 0.2154. In complex 1, the dimeric copper acetate units are linked through 4,4’-bipyridine to yield ID molecular ladders. These ladders are connected via O-H…O hydrogen bonds to generate 2D layers, which are further linked through C-H…O hydrogen bonds to give a 3D supramolecular network.

Gluing support τ-tilting modules via symmetric ladders of height 2

Gluing techniques with respect to a recollement have long been studied. Recently, ladders of recollements of abelian categories were introduced as important tools. In this paper, we present explicit constructions of gluing support τ-tilting modules via symmetric ladders of height two. Moreover, we apply the result to triangular matrix algebras to give a detailed version of the known Jasso's reduction and study maximal green sequences.

Number of embeddings of circular and Mbius ladders on surfaces

There are many results on the flexibility of(general) embeddings of graphs,but few are known about that of strong embeddings.In this paper,we study the flexibility of strong embeddings of circular and Mbius ladders on the projective plane and the Klein bottle by using the joint tree model of embeddings.The numbers of(nonequivalent) general embeddings and strong embeddings of circular and Mbius ladders on these two nonorientable surfaces are obtained,respectively.And the structures of those strong embeddings are described.

GA118-8B国产遗传分析仪的性能质量评定方法研究

研究GA118-8B国产遗传分析仪性能质量的评定方法,使用国产毛细管8通道毛细管阵列,应用等位基因靶点及Gene ScanT M-500LIZ,研究温度均一性分布情况、基因座片段大小的精确度,以及分型情况等。实验数据表明,DNA国产遗传分析仪实现了空间校正及光谱校正通过,单碱基分辨力为1bp,总长度为500bp的筛分过程,等位基因分型数据通过,恒温箱温度均一性良好,机器基线噪声值低,每个基因座的片段大小分子量标准差值小于0.1。通过该分析仪的性能质量评定方法,也为其质量鉴定和精确度性能要求提供了数据支撑。

Topological phases and edge modes of an uneven ladder

We investigate the topological properties of a two-chain quantum ladder with uneven legs,i.e.,the two chains differ in their periods by a factor of 2.Such an uneven ladder presents rich band structures classified by the closure of either direct or indirect bandgaps.It also provides opportunities to explore fundamental concepts concerning band topology and edge modes,including the difference of intracellular and intercellular Zak phases,and the role of the inversion symmetry(IS).We calculate the Zak phases of the two kinds and find excellent agreement with the dipole moment and extra charge accumulation.We also find that configurations with IS feature a pair of degenerate two-side edge modes emerging as the closure of the direct bandgap,while configurations without IS feature one-side edge modes emerging as not only the closure of both direct and indirect bandgaps but also within the band continuum.Furthermore,by projecting to the two sublattices,we find that the effective Bloch Hamiltonian corresponds to that of a generalized Su–Schrieffer–Heeger model or the Rice–Mele model whose hopping amplitudes depend on the quasimomentum.In this way,the topological phases can be efficiently extracted through winding numbers.We propose that uneven ladders can be realized by spin-dependent optical lattices and their rich topological characteristics can be examined by near future experiments.

Analysis of the Application of the Ladder Teaching Method Combined with Case Teaching in Otolaryngology Nursing Teaching

Objective:To analyze the feasibility of adopting a combined ladder and case teaching method in otolaryngology nursing teaching.Method:Nursing students in the otolaryngology department were selected.According to the admission time of nursing students,30 nursing students formed a control group(conventional nursing teaching),and 30 nursing students who were admitted later formed an observation group(ladder and case teaching method).The learning performance and teaching effectiveness of nursing students under different teaching methods were analyzed.Result:The academic performance and teaching effectiveness of the observation group were higher than those of the control group(P<0.05).Conclusion:The implementation of the ladder and case teaching method during the teaching of otolaryngology nursing significantly improved the student’s academic performance and teaching effectiveness.This method has great practical value.

Nonlinear Correction to Stark Ladders

The problem of a band electron in a crystal with alternating hoppings is investigated in the presence of a uniform electric field.Exact solutions for the energy spectrum and the wave functions are obtained with the help of SU(2) symmetry.It is found that the energy spectrum contains all orders of the reciprocal of the applied electric field besides the usual Stark ladders.A theoretical analysis shows that in the weak field regime,such nonlinear terms will dominate the localization behavior of the band electron.Only in the strong field regime am the Wannie-Stark localization be observed manifestly.The onset magnitude of the electric field strength for the occurrence of the Wannie-Stark localization is about 2×105V/m for common semiconductor superlattices,which is consistent with experimental observations.

Investigation on thermal characteristics and desensitization mechanism of improved step ladder-structured nitrocellulose

Nitrocellulose,or cellulose nitrate,has received considerable interest due to its various applications,such as propellants,coating agents and gas generators.However,its high mechanical sensitivity caused many accidents during its storage and usage in ammunition.In this work,two kinds of insensitive step ladderstructured nitrocellulose(LNC)with different nitrogen contents were synthesized.The products were characterized by FT-IR,Raman,XRD,SEM,elemental analysis,TGA,DSC,accelerating rate calorimeter analysis(ARC),and drop weight test to study their molecular structure,thermal characteristics and desensitization performance.Compared with raw nitrocellulose,LNC has a sharper exothermic peak in the DSC and ARC curves.The H50values of the two kinds of LNC increased from 25.76 to 30.01 cm for low nitrogen content and from 18.02 to 21.84 cm for high nitrogen content,respectively.The results show that the ladder-structure of LNC which provides regular molecular arrangement and a soft buffer made with polyethylene glycol could affect the energy releasing process of LNC and reduce the sensitivity of LNC.Insensitive LNC provides an alternative to be used as a binder in insensitive propellants formulation.

An 80-GHz DCO utilizing improved SC ladder and promoted DCTL-based hybrid tuning banks

An 80-GHz DCO based on modified hybrid tuning banks is introduced in this paper.To achieve sub-MHz frequency res-olution with reduced circuit complexity,the improved circuit topology replaces the conventional circuit topology with two binary-weighted SC cells,enabling eight SC-cell-based improved SC ladders to achieve the same fine-tuning steps as twelve SC-cell-based conventional SC ladders.To achieve lower phase noise and smaller chip size,the promoted binary-weighted digi-tally controlled transmission lines(DCTLs)are used to implement the coarse and medium tuning banks of the DCO.Compared to the conventional thermometer-coded DCTLs,control bits of the proposed DCTLs are reduced from 30 to 8,and the total length is reduced by 34.3%(from 122.76 to 80.66μm).Fabricated in 40-nm CMOS,the DCO demonstrated in this work fea-tures a small fine-tuning step(483 kHz),a high oscillation frequency(79-85 GHz),and a smaller chip size(0.017 mm^(2)).Com-pared to previous work,the modified DCO exhibits an excellent figure of merit with an area(FoMA)of-198 dBc/Hz.

A Secure Hardware Implementation for Elliptic Curve Digital Signature Algorithm

Since the end of the 1990s,cryptosystems implemented on smart cards have had to deal with two main categories of attacks:side-channel attacks and fault injection attacks.Countermeasures have been developed and validated against these two types of attacks,taking into account a well-defined attacker model.This work focuses on small vulnerabilities and countermeasures related to the Elliptic Curve Digital Signature Algorithm(ECDSA)algorithm.The work done in this paper focuses on protecting the ECDSA algorithm against fault-injection attacks.More precisely,we are interested in the countermeasures of scalar multiplication in the body of the elliptic curves to protect against attacks concerning only a few bits of secret may be sufficient to recover the private key.ECDSA can be implemented in different ways,in software or via dedicated hardware or a mix of both.Many different architectures are therefore possible to implement an ECDSA-based system.For this reason,this work focuses mainly on the hardware implementation of the digital signature ECDSA.In addition,the proposed ECDSA architecture with and without fault detection for the scalar multiplication have been implemented on Xilinxfield programmable gate arrays(FPGA)platform(Virtex-5).Our implementation results have been compared and discussed.Our area,frequency,area overhead and frequency degradation have been compared and it is shown that the proposed architecture of ECDSA with fault detection for the scalar multiplication allows a trade-off between the hardware overhead and the security of the ECDSA.

三种猕猴桃多酚粗提物对A549和Hela细胞的抑制作用

使用60%的乙醇提取三种猕猴桃多酚,离心后上清液通过旋转蒸发仪真空浓缩获得猕猴桃多酚粗提物,通过细胞形态分析、MTT实验以及DNALadder实验分析三种猕猴桃粗提物对A549和Hela细胞的抑制作用。结果表明狗枣猕猴桃多酚粗提物具有较好的抗肿瘤增殖活性,因此,软枣猕猴桃多酚可以作为新的癌症抑制剂,具有潜在的应用价值。

Parasiticein诱导烟草细胞凋亡的形态及生化特征

【目的】研究烟草细胞对parasiticein的反应,了解parasiticein诱导烟草细胞的PCD的发生机制。【方法】用浓度约100nmol·L-1的parasiticein处理烟草悬浮细胞,相差显微镜下观察细胞的形态变化。【结果】发现烟草细胞的细胞膜收缩,与细胞壁间形成空隙,原生质浓缩等;用trypanblue染色后观察到类似现象。对诱导处理的悬浮细胞经DAPI(4,6-diamino-2-phenylindole)染色后,通过荧光显微镜观察,发现细胞核先后表现染色质凝集、形成颗粒状等特征;对处理的悬浮细胞提取基因组DNA并进行琼脂糖凝胶电泳,可观察到梯状的DNA条带(DNA laddering)。研究还发现,parasiticein诱导的烟草细胞死亡可被蛋白激酶信号通路抑制剂K252-a部分抑制。【结论】parasiticein诱导的烟草细胞死亡具有细胞凋亡的典型形态及生化特征,是一种主动的细胞死亡过程。

干旱胁迫诱导苹果属植物细胞程序性死亡的研究

用聚乙二醇(polyethylene glycol,PEG6000)对苹果属植物平邑甜茶(Malus hupehensis pamp Reld.)和新疆野苹果〔M.sieversii(Ledeb)Roem.〕幼苗进行水分胁迫处理,通过Southern杂交和Western杂交的方法检测胁迫条件下幼苗体内DNA Ladder及Caspase-3蛋白酶。Southern杂交结果表明,干旱处理后,两种苹果的根和叶片中都有DNA Ladder产生;Western杂交结果显示,在苹果的叶片中有杂交印迹,而根中没有。这说明干旱胁迫可以诱导两种苹果属植物发生细胞程序性死亡,并且在细胞程序性死亡过程中叶片中都有类Caspase-3蛋白酶的产生。

超椭圆曲线上Montgomery标量乘的快速计算公式

超椭圆曲线密码体制与椭圆曲线密码体制相比，具有安全性高、密钥短的特点．标量乘计算是这两个密码体制中最为核心和重要的计算，其中，Montgomery阶梯算法是计算标量乘的一种重要算法，且因为其可以抵抗简单的边带信道攻击，而被广泛研究和应用．近几年，椭圆曲线上的Montgomery阶梯算法和相应的点运算公式一直在不断改进，但是在超椭圆曲线上，直接设计快速运算公式来提高Montgomery阶梯算法的速度，却一直没有太大的进展．Lange曾经探讨过这种快速公式存在的可能性，但却并没有得到一个实用、有效的计算公式．在特征为2的域上，通过改进超椭圆曲线上的除子类加法公式来提高超椭圆曲线上的Montgomery阶梯标量乘计算，提出了一种新的思路来改进多种坐标系下的加法公式．分析和仿真结果表明，在特征为2的域上，新的运算公式的运行速度比之前的标准公式均有所提高．在某类常用曲线上，新的公式比之前的公式快了4％～8．3％．这说明，直接设计快速除子运算公式来提高Montgomery阶梯算法的速度是可行的．同时，使用新的公式实现的Montgomery阶梯算法可以抵抗简单边带信道攻击．

ATM在人胃癌细胞系的表达及其在细胞DNA损伤中的作用

目的:研究DNA损伤剂对ATM基因缺陷和正常的胃癌细胞系的作用机制。方法:Western-blot方法检测6株胃癌细胞系ATM蛋白的表达情况,并用DNA损伤剂顺铂作用于ATM基因缺陷的MKN28细胞系和ATM基因正常的BGC823细胞系,采用Western-blot、DNAladder、Hoechest33258/PI双荧光染色等方法观察凋亡相关激酶的表达和细胞的应答反应。结果:Western-blot显示,ATM蛋白在胃癌细胞系MGC803、MKN28、MKN45、SGC7901的表达水平显著低于BGC823和AGS细胞系,BGC823细胞在CDDP作用后,ATM蛋白表达水平升高,磷酸化chk1和chk2活性24小时后增强,而Cdc25C表达减少;MKN28细胞中G2期检测点蛋白ATM、p-chk1、p-chk2表达较低,Cdc25C表达较高,但在CDDP作用前后无明显变化。MKN28细胞在DNA损伤剂作用后出现显著凋亡,而BGC823细胞在DNA损伤剂作用48小时后未见显著凋亡。结论:ATM在细胞周期的多个环节均有调控作用,特别是在细胞周期检测点和DNA损伤的修复中有重要的监视和启动作用。

三肽化合物酪丝缬肽对人肝癌BEL-7402细胞增殖抑制作用的实验研究

目的观察三肽化合物酪丝缬肽(tyroservaltide,YSV)对体外培养人肝癌BEL7402细胞增殖的抑制作用。方法建立人肝癌BEL7402及Chang氏肝细胞体外培养体系,用BrdU法、MTT法及LDH法,观察YSV对体外培养的BEL7402细胞、Chang氏肝细胞DNA分裂指数、MTT代谢率、LDH释放量的影响,用琼脂糖凝胶电泳观察药物对体外培养BEL7402细胞DNA片段化的影响。结果YSV对BEL7402细胞作用48h、72h时药物浓度为1mg·L-1和0.1mg·L-1组与阴性对照组比较:①能显著抑制肿瘤细胞DNA的合成(P<0.01),抑制率最高为药物浓度1mg·L-1作用72h时可达32.53%,②能表现出明显抑制细胞代谢的作用(P<0.05)其中YSV0.1mg·L-1作用72h时抑制率最高为19.12%,③能增加胞浆内LDH的释放(P<0.05),YSV(1mg·L-1)作用72h时抑制率最高,为36.13%,④能诱导BEL7402肝癌细胞DNA片断化成低分子量DNA,经1%琼脂糖电泳后显示为DNALadder。对正常肝细胞系Chang氏肝仅0.1mg·L-1在48h表现出抑制DNA合成能力的作用。结论YSV抑制人肝癌BEL7402细胞的增殖,对正常肝细胞系Chang氏肝没有影响。

还原型谷胱甘肽对抗硫芥诱导大鼠脾淋巴细胞毒性作用

目的观察还原型谷胱甘肽(glutath ione,GSH)对硫芥(su lfurmustard,SM)诱导大鼠脾淋巴细胞线粒体功能的保护作用。方法用密度梯度离心法分离大鼠脾淋巴细胞,与硫芥共同进行体外培养。用MTT法检测线粒体功能状态;用荧光分光法检测细胞内GSH含量和用琼脂糖DNA凝胶电泳观察DNA的损伤。结果硫芥作用的线粒体功能变化具有剂量和时间依赖性,它与细胞内GSH含量下降呈直线正相关(P<0.01)。使用GSH后,对不同剂量组的线粒体功能早期均有保护作用。保护效果最好时间的DNA断裂情况有所减轻,甚至可以逆转坏死向凋亡发展。结论GSH可部分保护线粒体功能。