Propagation of Airy beams from right-handed material to left-handed material

Based on the ABCD matrix formalism,the propagation property of an Airy beam from right-handed material（RHM） to left-handed material（LHM） is investigated.The result shows that when the Airy beam propagates in the LHM,the intensity self-bending due to its propagation in the RHM can be compensated.In particular,if the propagation distance in the RHM is equal to that in the LHM and the refractive index of the LHM is n L =-1,the transverse intensity distribution of the Airy beam can return to its original state.

A monolithic distributed phase shifter based on right-handed nonlinear transmission lines at 30 GHz

The epitaxial material, device structure, and corresponding equivalent large signal circuit model of GaAs planar Schottky varactor diode are successfully developed to design and fabricate a monolithic phase shifter, which is based on right-handed nonlinear transmission lines and consists of a coplanar waveguide transmission line and periodically distributed GaAs planar Schottky varactor diode. The distributed-Schottky transmission-line-type phase shifter at a bias voltage greater than 1.5 V presents a continuous 0°–360° differential phase shift over a frequency range from 0 to 33 GHz. It is demonstrated that the minimum insertion loss is about 0.5 dB and that the return loss is less than-10 dB over the frequency band of 0–33 GHz at a reverse bias voltage less than 4.5 V. These excellent characteristics, such as broad differential phase shift, low insertion loss, and return loss, indicate that the proposed phase shifter can entirely be integrated into a phased array radar circuit.

High-Gain Array Antenna Based on Composite Right/Left-Handed Transmission Line

In this paper a metamaterial-inspired antenna with high gain and good directivity is designed. Based on the concept of composite right/left-handed transmission line (CRLH-TL), the proposed antenna is realized based on three leakage wave unit cell and a left handed circular ring slot incorporated on the surface. The maximum achievable gain at the resonant frequency of 5.6GHz is 6.933 dBi, and the return loss at 5.6 GHz can be –20 db. This proposed design has a simple structure and a compact dimension of 35 mm*40 mm*1 mm, which is suitable for particular wireless communication application such as WiFi and WLAN.

Wider frequency domain for negative refraction index in a quantized composite right–left handed transmission line

The refraction index of the quantized lossy composite right-left handed transmission line（CRLH-TL） is deduced in the thermal coherence state. The results show that the negative refraction index（herein the left-handedness） can be implemented by the electric circuit dissipative factors（i.e., the resistances R and conductances G） in a higher frequency band（1.446 GHz≤ ω ≤ 15 GHz）, and flexibly adjusted by the left-handed circuit components（Cl, Ll） and the right-handed circuit components（Cr, Lr） at a lower frequency（ω = 0.995 GHz）. The flexible adjustment for left-handedness in a wider bandwidth will be significant for the microscale circuit design of the CRLH-TL and may make the theoretical preparation for its compact applications.

Design of Miniaturized Band-Pass Filter with Composite Right/Left-Handed Transmission Line

In this paper, a new miniaturized wide-pass-band filter at U band based on composite right/left- handed transmission line (CRLH TL) is implemented. The CRLH TL contributed to a broadband filter is a balanced structure with a small size of only 1.428 mm*0.5530 mm. The frequency characteristics are simulated and the results show that the 3 dB band width of the proposed filter is about 13.5 GHz from 45.8 GHz to 59.3 GHz. The insertion loss is quite flat through the pass-band and the return loss is relatively low.

（3＋1）-dimensional nonlinear propagation equation for ultrashort pulsed beam in left-handed material

In this paper a comprehensive framework for treating the nonlinear propagation of ultrashort pulse in metamaterial with dispersive dielectric susceptibility and magnetic permeability is presented. Under the slowly-evolving-wave approximation, a generalized （3＋1）-dimensional wave equation first order in the propagation coordinate and suitable for both right-handed material （I^HM） and left-handed material （LHM） is derived. By the commonly used Drude dispersive model for LHM, a （3＋1）-dimensional nonlinear Schrodinger equation describing ultrashort pulsed beam propagation in LHM is obtained, and its difference from that for conventional RHM is discussed. Particularly, the self-steeping effect of ultrashort pulse is found to be anomalous in LHM.

TM modes in asymmetric slab waveguides with left-handed material

Three-layer slab waveguide with left-handed materials （LHM） is discussed using the Maxwell＇s equations and their equations of dispersion relation for TM modes are obtained. By seeking the power of the slab waveguide, their equations of effective thickness for TM modes are obtained. Furthermore, the interrelated equations for right-handed materials （RHM） slab waveguide are introduced and their curves plotted. To find new properties for LHM slab waveguide, the equations and their curves for the LHM and RHM slab waveguide are compared respectively.

Class of numerical methods for differential-algebraic systems with discontinuous right-hand sides

Numerical methods for Differential-Algebraic systems with discontinuous right-hand sides is discussed. A class of continuous Rosenbrock methods are constructed, and numerical experiments show that the continuous Rosenbrock methods are effective. Applying the methods, a fast and high-precision numerical algorithm is given to deal with typical discontinuous parts, which occur frequently in differential-algebraic systems(DAS).

Advocating Human Rights Protection by Rule of Law, Supporting Human Rights Undertaking with a Giant Hand——Deep Condolences to Dear Former President Luo Haocai

Chairman Luo Haocai served as the president of CSHRS from 2007 to 2016.During those nine years, he built deep friendships with researchers on human rights.Because President Luo served as vice chairman of the National Committee of CPPCC for a long time, we were used to calling him "Chairman Luo." Chairman Luo was a leader with strategic and overall awareness, a scholar-official, an elder with a young mentality, and a motivator and protector of young people.

Changes in motor function in the unaffected hand of stroke patients should not be ignored

Motor function changes in the unaffected hand of stroke patients with hemiplegia. These changes are often ignored by clinicians owing to the extent of motor disability of the affected hand. Finger tapping frequency and Lind-mark hand function score showed that the motor function of unaffected hands in stroke patients was poorer than that of a healthy control hand. After 2 weeks of rehabilitation treatment, motor function of the unaffected hand of stroke patients was obviously improved. Therefore, attention should also be paid to motor function in the unaffected hand of stroke patients with hemiplegia during rehabilitation.

FMRI and EEG Reactions to Hand Motor Tasks in Patients with Mild Traumatic Brain Injury: Left-Hemispheric Sensitivity to Trauma

Background: Mild traumatic brain injury (mTBI) is one of the most common forms of cerebral pathology in young people and disorders involve dysfunctions in cognitive and motor spheres. We would like to examine the structural and functional alterations of the brain in patients with mTBI while performing hand movements. Methods: Twenty healthy right-handed subjects (age 25.1 ± 3.9) and 10 patients (age 27.9 ± 7.3) with mTBI without hemiparesis participated in the study using functional magnetic resonance imaging (fMRI) and electroencephalography (EEG). FMRI and EEG reactions were analysed during right- and left-hand movements. Results: It was shown that fMRI reactive changes have a larger inter-individual variability of activation during left-hand movements in comparison with right-hand ones in healthy subjects. The TBI patients demonstrated an increase of a diffuse component of fMRI reactive changes compared to healthy people. A greater number of the brain structures was involved, mainly at the subcortical level, mostly in the left hemisphere during right-hand movement. EEG study demonstrated coherence changes for the slow (delta) frequency bands in the left hemisphere, while performing both hand movements. In healthy persons, EEG coherence changes were observed in the fast (alhpa2) frequency band predominantly in contralateral hemispheres, while performing hand movements. Conclusion: So, fMRI and EEG studies revealed the most expressed pathological reactive changes in the left hemisphere and the brain cortical structures during right-hand movements in patients after mTBI. These data allowed us to propose that the younger brain structures were the most sensitive to mTBI.

腹腔镜下左右手打结缝合在子宫全切术中的应用价值探究

目的:探究腹腔镜下左右手打结缝合在子宫全切术中的应用价值。方法:选取2021年4月—2023年11月于玉林市第一人民医院拟行腹腔镜下子宫全切术的患者90例为研究对象,随机分为传统组、双极电凝组、左右手组,各30例。传统组实施腔内传统打结缝合,双极电凝组实施双极凝闭血管,左右手组实施左右手打结缝合。对比三组手术情况、疼痛评分、生活质量。结果:左右手组手术时间、切口愈合时间、住院时间短于传统组与双极电凝组,术中出血量少于传统组与双极电凝组(P<0.05);术后1、3 d,左右手组视觉模拟评分法评分低于传统组与双极电凝组(P<0.05);术后,三组各项世界卫生组织生活质量测定简表评分升高,左右手组生活质量评分均高于传统组、双极电凝组(P<0.05)。结论:在腹腔镜下行子宫全切术中,对出血点进行左右手打结缝合子宫血管后再切断,可显著减少术中出血量,缩短手术时间,减轻患者疼痛,提高生活质量。

面向卫星通信的K波段低剖面可重构线圆极化变换表面

针对K波段卫星通信容量大、工作模式灵活的需求,设计了一款用于K波段卫星通信的反射型可重构线圆极化变换表面。该线圆极化变换表面基于改进型耶路撒冷十字结构,在PIN二极管导通和关闭时,分别可在18.59~20.50 GHz和18.66~23.19 GHz实现线极化波转右旋圆极化波和左旋圆极化波,重叠工作频段为18.66~20.50 GHz,带宽1.84 GHz。该极化变换表面的单元尺寸为0.22λ×0.2λ×0.083λ(λ为重叠频段中心工作波长),剖面高度仅为0.083λ。该极化变换表面在PIN二极管处于导通和关闭状态下,入射角度稳定性分别为40°和20°,且交叉极化电平低于-60 dB。

经食道超声心动图右心声学造影中应用手振加血激活生理盐水显影对卵圆孔未闭的诊断价值

目的 探讨经食道超声心动图右心声学造影(TEE-cTTE)中应用手振加血激活生理盐水(ASB)显影对卵圆孔未闭(PFO)的诊断价值。方法 选取2020年7月至2023年1月临汾市人民医院疑似PFO患者106例,根据相关诊断标准分为PFO组(78例)与非PFO组(28例),均行TEE-cTTE检查,根据造影剂类型分为ASB、手振激活50%葡萄糖溶液(AGB)、手振激活生理盐水(AS),对比3种造影剂右心开始显影到微气泡逐渐减少到每帧图像低于10个微气泡的时间(T-R)、两组卵圆孔内径和隧道长度,分析3种造影剂行TEE-cTTE检查对PFO、PFO类型及右向左分流(RLS)的诊断价值。结果 ASB静息状态下、Valsalva动作下T-R长于AGS、AS,AGS静息状态下、Valsalva动作下T-R长于AS(P<0.05);3种造影剂检测PFO组卵圆孔内径长于非PFO组(P<0.05);ASB、AGS检测的PFO组卵圆孔内径长于AS检测(P<0.05);ROC曲线分析,ASB行TEE-cTTE诊断PFO的AUC为0.872(95%CI 0.793~0.929),敏感度为92.31%(72/78),特异度为82.14%(23/28);AGS行TEE-cTTE诊断PFO的AUC为0.842(95%CI 0.758~0.905),敏感度为89.74%(70/78),特异度为78.57%(22/28);AS行TEE-cTTE诊断PFO行TEE-cTTEAUC为0.672(95%CI 0.574~0.760),敏感度为80.77%(63/78),特异度为53.57%(15/28),提示ASB、AGS行TEE-cTTE诊断PFO的价值优于AS;ASB行TEE-cTTE检查诊断PFO类型、RLS分级与临床诊断结果的一致性较高(Kapp值=0.819、0.838);AGS行TEE-cTTE检查诊断PFO类型、RLS分级与临床诊断结果的一致性一般(Kapp值=0.653、0.655);AS行TEE-cTTE检查诊断PFO类型与临床诊断结果的一致性较差(Kapp值=0.393),诊断RLS分级与临床诊断结果的一致性一般(Kapp值=0.480)。结论 TEE-cTTE检查中应用ASB显影能延长T-R时间,提高PFO诊断价值,且在诊断PFO类型、RLS分级方面表现出与临床诊断结果较高的一致性,有利于开展具有针对性、科学性的临床诊治工作。

非连续免疫对一类丙型肝炎SICR模型的影响

研究了一类右端不连续的丙肝SICR微分模型,利用微分包含理论和构造Lyapunov函数,证明了模型地方病平衡点和无病平衡点的存在唯一性,通过计算得到了模型的基本再生数R_(0),分析证明了各平衡点在有限时间内的全局渐近稳定性.文末借助MATLAB数值仿真验证了理论的准确性.

基于复合左右手传输线的超窄带基片集成波导有耗滤波器

基于四分之一模基片集成波导结构,提出了一款小型化的超窄带有耗滤波器。通过在谐振器内部添加复合左右手传输线以及电阻耦合,不但使整个电路结构变得更加紧凑,还实现了通带内的平坦化以及阻带性能的提升。使用本振模仿真的方法得到了对应谐振器的大小,并将两个腔体进行级联,然后再加入电阻耦合以及左右手传输线,设计出一款超窄带的小型化基片集成波导有耗滤波器。仿真结果显示:滤波器的工作频率为3.65 GHz,带宽为200 MHz,相对带宽为5.4%,带内插损为1 dB,回波损耗优于28 dB。相较于传统滤波器设计,该结构实现了小型化、超窄带以及更高的回波损耗。为了验证设计结构的准确性,进行了实物加工测试,仿真与实测结果吻合良好。

Miniaturized fractal-shaped branch-line coupler for dual-band applications based on composite right/left handed transmission lines

In this paper,novel dual-band (DB) branch-line couplers (BLCs) employing a composite right/left handed transmission line (CRLH TL) and fractal geometry are presented for the first time.The CRLH TL,with specified characteristic impedance and phase shift,consists of lumped elements for the left handed (LH) part and fractal-shaped microstrip lines (MLs) for the right handed (RH) part,which can be designed separately.Two designed BLCs are involved in size reduction,one using a 3/2 fractal curve of first iteration,the other constructed based on a hybrid shape of fractal and meandered lines.A miniaturized principle for CRLH TL realization is derived and an exact design method for fractal implementation is developed.For verification,an example coupler was fabricated and measured.Consistent numerical and experimental results confirmed the design concept,showing that the BLCs obtain DB behavior centered at 0.9 GHz and 1.8 GHz respectively with good in-band performance,except for slightly larger coupled insertion loss for the hybrid-shaped BLC case.In addition,the proposed fractal-and hybrid-shaped BLCs obtained a 49.7% and 64.1% size reduction respectively relative to their conventional counterparts working in the lower band.The most important contributions of this article are the demonstration of compatibility between the fractal and CRLH TL techniques and the provision of an alternative approach and a new concept for designing devices.

Harmonic suppressed bandpass filter using composite right/left handed transmission line

A wideband composite right/left handed transmission line (CRLH TL) in conjunction with its corresponding equivalent circuit model is studied based on a cascaded complementary single split ring resonator (CCSSRR).The characterization is performed by theory analysis,circuit simulation,and full-wave electromagnetic (EM) simulation.The negative refractive index (NRI) and backward wave propagation performance of the CRLH TL are demonstrated.For application,a bandpass filter (BPF) with enhanced out-of-band selectivity and harmonic suppression operating at the wireless local area network (WLAN) band is designed,fabricated,and measured by combining the CRLH TL with a complementary electric inductive-capacitive resonator (CELC).Three CELC cells with wideband stopband performance in the conductor strip and ground plane,respectively,are utilized in terms of single negative permeability.The design concept has been verified by the measurement data.

Study on relationships of electromagnetic band gap structures and left/right handed structures

Two types of dual periodic circuits are introduced. The distributions of passbands and stopbands are generated from their dispersion relationships. Based on the study, Brillouin diagrams of three representative special cases are drawn; S parameters of these three cases are simulated by Aglient ADS; the S parameters of one of the three cases are verified by an experiment. The phase characteristics are compared with those generated from the dispersion relationship. The theoretical analysis and the experimental verification show that both types of the periodic structures can behave as electromagnetic band gap （EBG） structures, right-handed structures （RHS）, and left-handed structures （LHS）, when they operate at different frequency ranges. Thus, the possibility of a physical structure showing these three different characteristics at different frequency ranges is proven.

基于悬链线结构的多功能二向色性超构表面

超构表面是一种由亚波长单元结构组成的人工表面,展现出巨大的电磁波操纵潜力,悬链线电磁学为超构表面的设计提供了新的思路和方法。本文提出一种基于悬链线结构的多功能二向色性超构表面,能够在不同方向上实现对电磁波的选择吸收。仿真结果显示,该器件可在红外区域实现92%的线性二色性(LD)和96%的圆二色性(CD)。这两种功能仅需改变电磁波的入射方向就可同时实现,且两种功能在一定入射角范围内均具有较高的效率。此外,还分析了不同几何参数对吸收性能的影响,以及实现不同电磁波选择吸收的物理机制。该超构表面具有结构简单、便于集成以及应用范围广的优点,在成像、传感和光谱等领域具有潜在的应用前景。