Lasing with resonant feedback in weakly scattering random systems

Laser action in active random media in the weak scattering regime far from Anderson localization is investigated by coupling Maxwell's equations with the rate equations of a four-level atomic system. We report systematic lasing action with resonant feedback and show that the lasing modes mostly consist of traveling waves spatially extended over the whole system. Next we address the question of the origin of the feedback mechanism in such a system where no disorder-induced long-lived resonances are available, and present strong evidence that they correspond to the quasimodes of the passive system. This in turn provides an original way to access the spatial distribution of the quasimodes of a non-Hermitian system.     

Turbulence control with local pacing and its implication in cardiac defibrillation

In this review article, we describe turbulence control in excitable systems by using a local periodic pacing method. The controllability conditions of turbulence suppression and the mechanisms underlying these conditions are analyzed. The local pacing method is applied to control Winfree turbulence (WT) and defect turbulence (DT) induced by spiral-wave breakup. It is shown that WT can always be suppressed by local pacing if the pacing amplitude and frequency are properly chosen. On the other hand, the pacing method can achieve suppression of DT induced by instabilities associated with the motions of spiral tips while failing to suppress DT induced by the instabilities of wave propagation far from tips. In the latter case, an auxiliary method of applying gradient field is suggested to improve the control effects. The implication of this local pacing method to realistic cardiac defibrillation is addressed.     

A Feasible and Quantitative Encoding Method for Microbeads with Multicolor Quantum Dots

Multicolor encoded beads were achieved by incorporating two color core-shell quantum dots (QDs) (CdSe/ZnS) to commercial polystyrene (PS) beads. By controlling the concentration ratios of the two quantum dots (QDs) in doping solutions, a series of codes with different intensity ratios were obtained. Based on the multiple encoded carboxylic modified polystyrene beads, fluorescent dyes labeled antibodies were distinguished successfully on the beads’ surface. It suggests that the encoded beads from this method have the practicability in biological applications and chemical analysis. Hai-Qiao Wang and Zhen-Li Huang authors contribute equally to this work     

Near Infrared Spectroscopy of the Cretaceous Red Beds in Inner Mongolia DongshengmiaoSCIEI北大核心CSCD

Take the cores and surface weathered soil from the Cretaceous red beds in the western of Dongshengmiao mine of Inner Mongolia and analysis with near-infrared spectroscopy. The result shows that near-infrared spectroscopy can identify mineral quickly through the characteristic absorption peaks of each group. The Cretaceous red beds in the western of Dongshengmiao mine is argillaceous cementation, it is mainly composed of quartz, feldspar, montmorillonite, illite, chlorite, muscovite etc, the mineral composition is mainly affected by the upstream source area. The clay mineral like montmorillonite water swelling and uneven drying shrinkage expands the original crack and creates new cracks, reduces its strength, which is the mainly reason of its disintegration. According to the composition of clay mineral, we speculate its weathering process is mainly physical weathering, the climate during the weathering is cold and dry. The results can not only improve the geological feature of the mining area, but also show that the near-infrared spectroscopy technology can analyze the mineral composition of soil and rock effectively on the basis of Mineral spectroscopy, which demonstrates the feasibility of the near-infrared spectroscopy can analyze minerals in soil and rock quickly, that shows the feasibility in geology study, provides new ideas for the future research of soil and rock.     

肝豆状核变性患者的肾脏病变特点及长期使用青霉胺的影响研究

目的 探讨肝豆状核变性患者肾脏病变的特点及长期使用青霉胺治疗对其产生的可能影响。方法 选取70 例临床 确诊为肝豆状核变性患者作为观察组,根据临床表型和使用青霉胺时间分为肝脏型组、肝脑混合型组、脑型组及使用青霉胺＜5年组、5～10 年组、＞10 年组,检测并比较各组患者尿总蛋白（TG）、低分子量蛋白（LMW）、高分子量蛋白（HMW）、β2微球蛋白（β2-MG）、β－N-乙酰氨基葡萄糖苷酶（NAG）、白蛋白（ALG）及血肌酐（Scr）等肾脏病变相关指标;另选择无血缘关系且血铜蓝蛋白及铜氧化酶等铜代谢检查均正常的健康志愿者70 例作为对照组,检测上述指标并与观察组对照。结果 观察组的肾脏病变相关指标显著高于对照组;不同临床表型的患者各项指标间无统计学差异;随着服用青霉胺时间的延长,患者尿液中β2-MG、LMW百分比、NAG、TG水平逐渐降低,HMW 百分比、ALG水平逐渐升高,TG 呈现逐渐降低的趋势,Scr 保持不变。结论 肝豆状核变性患者肾小球和肾小管的功能均有明显的损伤;肾脏病变在不同临床表型之间无统计学差异,长期使用青霉胺治疗对肾小球的功能有一定的损伤。     

The Rayleigh law in silicon doped hafnium oxide ferroelectric thin films

A wealth of studies have confirmed that the low‐field hysteresis behaviour of ferroelectric bulk ceramics and thin films can be described using Rayleigh relations, and irreversible domain wall motion across the array of pining defects has been commonly accepted as the underlying micro‐mechanism. Recently, HfO₂ thin films incorporated with various dopants were reported to show pronounced ferroelectricity, however, their microscopic domain structure remains unclear till now. In this work, the effects of the applied electric field amplitude, frequency and temperature on the sub‐coercive polarization reversal properties were investigated for 10 nm thick Si‐doped HfO₂ thin films. The applicability of the Rayleigh law to ultra‐thin ferroelectric films was first confirmed, indicating the existence of a multi‐domain structure. Since the grain size is about 20–30 nm, a direct observation of domain walls within the grains is rather challenging and this indirect method is a feasible approach to resolve the domain structure. (© 2015 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim)     

Comparison of the 13C (C = N) chemical shifts of substituted N‐(phenyl‐ethylene)‐anilines and substituted N‐(benzylidene)‐anilines

Comparison of ¹³C NMR of C = N bond chemical shifts δ_C(C = N) in substituted N‐(phenyl‐ethylene)‐anilines XArC(Me) = NArY (XPEAYs) with that in substituted N‐(benzylidene)‐anilines XArCH = NArY (XBAYs) was carried out. The δ_C(C = N) of 61 samples of XPEAYs were measured, and the substituent effect on their δ_C(C = N) were investigated. The results show the factors affecting the δ_C(C = N) of XPEAYs are quite different from that of XBAYs. A penta‐parameter correlation equation was obtained for the 61 compounds, which has correlation coefficient 0.9922 and standard error 0.12 ppm. The result indicates that, in XPEAYs, the inductive effects of substituents X and Y are major factors affecting the δ_C(C = N), while the conjugative effect of them have very little effect on the δ_C(C = N) and can be ignored. The substituent‐specific cross‐interaction effects between X and Y and between Me of C = N bond and substituent Y are important factors affecting the δ_C(C = N). Also, the excited‐state substituent parameter of substitute Y has certain contribution to the δ_C(C = N). Copyright © 2015 John Wiley & Sons, Ltd.