Frustration and intermediate dimerized phase in spin ladder system

This paper studies a spin ladder model which possesses frustrating interactions. By using both the bosonization and the density matrix renormalization group techniques, it shows that the intermediate columnar dimerized phase, which exists in a narrow parameter region of the so-called ~/1 - J2 model, vanishes if the interchain frustration is weak and anisotropic. Therefore, it concludes that the frustrating interaction indeed plays an important role in producing such a phase. As a complementary to our previous investigation, it reaches a more complete picture of the quantum phase transition in the frustrated spin ladder systems.

Dynamically controlled optical nonreciprocity of a double-ladder system with spontaneously generated coherence in moving atomic optical lattice

A four-level double-ladder cold atoms system with spontaneously generated coherence trapped in a moving optical lattice is explored to achieve optical nonreciprocity. When spontaneously generated coherence（SGC） is present, the remarkable contrast optical nonreciprocity of light transmission and reflection can be generated at each induced photonic bandgap in the optical lattice with a velocity of a few m/s. However, when the SGC effect is absent, the optical nonreciprocity becomes weak or even vanishing due to the strong absorption. It is found that the optical nonreciprocity is related to the asymmetric Doppler effect in transmission and reflection, meanwhile the degree and position of optical nonreciprocity can be tuned by the SGC effect and the Rabi frequency of the trigger field.

Special modes induced by inter-chain coupling in a non-Hermitian ladder system

We explore some interesting phenomena in a simple non-Hermitian ladder system.Special modes with energy eigenvalues closely related to the inter-chain-coupling strength appear in the non-Hermitian ladder system.We show that a phase transition occurs whereby special modes with pure real eigenvalues can switch to special modes with pure imaginary eigenvalues,when the inter-chain-coupling strength changes from symmetric to asymmetric.We find that the density profiles of all the special modes are completely identical under certain conditions,even if the inter-chain-coupling strength is added into the non-Hermitian ladder system in different ways.Moreover,we also demonstrate that the different inter-chain couplings are fundamentally equivalent to adding different on-site potential energies into the non-Hermitian ladder system.

Ultrasound calibration with ladder phantom at multiple depths for breast biopsy navigation system

Ultrasound guided breast biopsy navigation system with a graphical user interface and a passive robotic needle holder is developed to increase the performance and reliability of the radiologist.Ultrasound calibration and tool tip calibration are required before using the system.A ladder phantom is developed to be used for ultrasound calibration in real time system with only one ultrasound image required.The passive robotic needle holder structure results in an identity matrix for the makes the rotation matrix;therefore,only translation and scaling are required in the system.This method can be applied to multiple ultrasound depths,which has a relationship at each depth and a relationship to the ultrasound image on the display.The results show high accuracy(<1 mm.)and rapid calibration(5–10 minutes)which is suitable for a real time system like a breast biopsy navigation system based on tests with a breast phantom.

Design and Implementation for Ladder Diagram in Hydropower Simulation System Based on All Paths Searching Algorithm

An approach to design and implement the control function of LD (Ladder Diagram) in the hydropower simulation system based on all paths searching algorithm is proposed in this paper. LD is widely used as a programming language for PLC (Programmable Logic Controller), but it doesn’t be executed automatically in the hydropower simulation system which is a software system, and there is no compiler or interpretation for LD in it. The approach in this paper is not only to present a graphical interface to design LD, but also implement its control function through transforming it to a corresponding undigraph, in which, all paths be-tween two vertexes (live wire and null line) are searched by the proposed algorithm. An application example is presented to verify the validity of the algorithm and shows that the algorithm is correct and practicable. In addition, how to implement the control function based on object-oriented thought is introduced. The running time is shown at last, which proves that the system with the algorithm can meet the real-time request in the hydropower simulation system.

Population transfer by femtosecond laser pulses in a ladder-type atomic system

The population transfer in a ladder-type atomic system driven by linearly polarized sech-shape femtosecond laser pulses is investigated by numerically solving Schr6dinger equation without including the rotating wave approximation （RWA）. It is shown that population transfer is mainly determined by the Rabi frequency （strength） of the driving laser field and the chirp rate, and that the ratio of the dipole moments and the pulse width also have a prominent effect on the population transfer. By choosing appropriate values of the above parameters, complete population transfer can be realized.

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.

Ladder型三能级介质中传播的少周期激光脉冲的空间分布

利用由时域有限差分法和预估校正法求得全波Maxwell-Bloch方程的数值解,研究少周期超短激光脉冲在Ladder型三能级原子介质中传播时脉冲及介质粒子布居的空间分布.结果表明,脉冲及介质粒子布居的空间分布规律随脉冲面积的改变而发生明显的变化.当脉冲面积较小时,脉冲形状不规则,振荡次数较多;当脉冲面积较大时,脉冲形状变得较为规则,振荡次数明显减少.随着脉冲面积的增大,脉冲振幅和传播速度逐渐增大,各能级粒子布居振荡次数增多,不同时刻的脉冲和粒子布居空间分布的变化明显减小.粒子布居的空间分布与脉冲的空间分布密切相关.

三能级Upper-ladder型系统中的无反转激光相位扩散效应(英文)

三能级Upper-ladder型系统中,在旋波、慢变振幅近似下,求解了考虑驱动场相位扩散后的系统密度矩阵运动方程,并给出了这个三能级梯型系统稳态线性解析解。利用对密度矩阵运动方程的稳态线性解析解的数值模拟结果,研究相位扩散对无反转激光增益、色散和粒子数差的影响;利用对密度矩阵运动方程的数值模拟结果,分析相位的扩散对无反转激光场及相应的各能级粒子数布居的时间演化规律的影响。驱动场相位扩散会导致无反转激光增益减小。线宽的存在阻碍了系统的无吸收高色散。线宽的变化不能改变ladder型系统输出(反转还是无反转)激光的特性。但线宽影响了系统达到稳态的时间以及时间演化过程中的相位扩散将导致相干的减弱。

利用基频与倍频脉冲控制扩展“ladder”式跃迁

利用含时量子波包动力学方法研究了两束基频与倍频脉冲控制下的扩展"ladder"式跃迁.通过基频与2倍频脉冲控制分子布居从|0,0>态跃迁至|5,0>与|5,2>态;基频与3倍频脉冲控制分子布居从|0,0>态跃迁至|5,3?与|6,2>态.计算结果表明,利用两束基频与倍频脉冲,通过"ladder"式跃迁,可以得到近100%的布居跃迁概率.两束脉冲间的相对相位角影响分子的布居分布.当脉冲频率比为1:2时,布居以π为周期变化;当脉冲频率比为1:3时,布居以2π为周期变化.

单位点等位基因Ladder的研制与应用

DNA等位基因Ladder是国产遗传分析仪质量检测及性能评价的必备试剂。基于DNA克隆技术,以单基因座(D2S1338)为靶位点,通过体外基因扩增方法获取基因座重复单位为11-24的等位基因,并与相应克隆载体连接构建该位点质粒克隆库,采用优选出的荧光标记引物对质粒DNA模板进行荧光PCR扩增,最终获得单STR位点高质量的等位基因Ladder,完全满足GA118-16A型遗传分析仪的质量检测和性能测试要求。

Influence of Femtosecond Laser Parameters on Autler-Townes Splitting of Three-Level Ladder Molecules

We theoretically investigate the Autler-Townes （AT） splitting in the photoelectron spectra of three-level ladder K2 molecule driven by a pump-probe pulse via employing the time- dependent wave packet approach. The dependence of AT splitting on two laser intensities and wavelengths are studied in detail. We firstly quantify these effects on peak shift and AT separation. The photoelectron spectra show double splitting with symmetric profiles, but with asymmetric profiles when the wavelength is changed. The magnitude of AT splitting increases with the pump laser intensity, but does not vary with probe intensity. The shifts of the absorption peaks and the splitting between AT doublet are predicted by using an analyt- ical fitting function when the intensity/wavelength of one of the two fields is changed. These novel results are of importance for the molecular spectroscopy and may further stimulate the first principles theoretical studies analytically.

山定子抗苹果褐斑病菌侵染过程中 DNA ladder 与类 caspases 活性的检测

接种褐斑病菌分生孢子悬浮液于山定子与富士苹果叶片,接种后1、3 d和5 d取样,提取DNA,检测DNA ladder;提取样品粗蛋白,用特异性荧光底物检测粗蛋白中类caspase活性,探索山定子受褐斑病菌侵染过程中引起的细胞程序性死亡(PCD)与抗性的关系,检测DNA ladder和类caspases活性变化的规律。研究发现:在接种后1、3 d和5 d,山定子和富士苹果叶片中没有明显DNA ladder的产生;受检测的YVADase、DEVDase、IETDase和VEIDase活性在接种后1 d和3 d没有显著变化,但在接种后5 d,活性均降低30%左右,显著低于对照。研究表明,山定子在褐斑病菌侵染过程中并没有DNA ladder产生,但却伴随着类caspase活性的下降。

A self-made, low-cost infrared system for evaluating the sciatic functional index in mice

The sciatic functional index（SFI） is a popular parameter for peripheral nerve evaluation that relies on footprints obtained with ink and paper. Drawbacks include smearing artefacts and a lack of dynamic information during measurement. Modern applications use digitized systems that can deliver results with less analytical effort and fewer mice. However, the systems are expensive（€40,000）. This study aimed to evaluate the applicability and precision of a self-made, low-cost infrared system for evaluating SFI in mice. Mice were subjected to unilateral sciatic nerve crush injury（crush group; n = 7） and sham operation（sham group; n = 4）. They were evaluated on the day before surgery, the 2nd, 4th and 6th days after injury, and then every day up to the 23rd day after injury. We compared two SFI evaluation methods, i.e., conventional inkand-paper SFI（C-SFI） and our infrared system（I-SFI）. Our apparatus visualized footprints with totally internally reflected infrared light（950 nm） and a camera that can only detect this wavelength. Additionally we performed an analysis with the ladder beam walking test（LBWT） as a reference test. I-SFI assessment reduced the standard deviation by about 33 percent, from 11.6 to 7.8, and cut the variance around the baseline to 21 percent. The system thus requires fewer measurement repetitions and fewer animals, and cuts the cost of keeping the animals. The apparatus cost €321 to build. Our results show that the process of obtaining the SFI can be made more precise via digitization with a self-made, low-cost infrared system.

Abstraction and operator characterization of fractal ladder viscoelastic hyper-cell for ligaments and tendons

This study investigates the viscoelastic behavior of soft bio-fibres in association with their fractal structures. A spring-dashpot fractal network with the self-similar topology, named the -type fractal ladder hyper-cell (FLHC), is abstracted from the micro/nano-structure of ligaments and tendons (LTs). Its constitutive operator is derived by the Heaviside operational calculus, which is of intrinsic fractional order. In terms of this operator, the long-term viscoelastic relaxation of bio-fibres arising from the fractal ladder topology is expounded. In addition, the fractional-order viscoelastic constitutive equation is obtained based on the FLHC of LTs, and its results are consistent with those of available human knee and spinal LT relaxation experiments. Results on the constitutive equation of FLHCs are formulated into two propositions. The multidisciplinary invariance and implications from the fractal ladder pattern of bio-fibres are also discussed.

Discrimination of neutron and gamma ray using the ladder gradient method and analysis of filter adaptability

This study proposes a ladder gradient method for neutron and gamma-ray discrimination.The proposed method exhibited state-of-the-art performance with low time consumption,which incorporates two parts:information extraction and discrimination factor calculation.A quasi-continuous spiking cortical model was proposed to extract information from the radiation pulse signals,thus generating an ignition map corresponding to each pulse signal.The ignition map can be used to calculate the discrimination factor.A ladder gradient calculation was introduced to obtain a discrimination factor with low computational complexity.The proposed method was compared with five other discrimination methods to evaluate its robustness and efficacy.Furthermore,the filter adaptability of the pulse-coupled neural network and ladder gradient methods was investigated.Possible reasons for adapting the conditions with different discrimination methods and filters were analyzed.Experiments were conducted in 20 filtering situations with 11 types of filters to determine the most suitable filters for discrimination methods.The experimental results revealed that the three most adaptive filters of the pulse-coupled neural networks and ladder gradient methods are the wavelet,elliptic,and median filters and the elliptic,moving average,and wavelet filters,respectively.

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.

Topological phases of a non-Hermitian coupled SSH ladder

We study topological phases of a non-Hermitian coupled Su-Schrieffer-Heeger(SSH) ladder. The model originates from the brick-wall lattices in the two-row limit. The Hamiltonian can be brought into block off-diagonal form and the winding number can be defined with the determine of the block off-diagonal matrix. We find the determine of the offdiagonal matrix has nothing to do with the interleg hopping of the ladder. So the topological phases of the model are the same as those of the chains. Further numerical simulations verify the analysis.

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.