Robust measurement of orbital angular momentum of a partially coherent vortex beam under amplitude and phase perturbations

The ability to overcome the negative effects,induced by obstacles and turbulent atmosphere,is a core challenge of long-distance information transmission,and it is of great significance in free-space optical communication.The spatial-coherence structure,that characterizes partially coherent fields,provides a new degree of freedom for carrying information.However,due to the influence of the complex transmission environment,the spatial-coherence structure is severely damaged during the propagation path,which undoubtedly limits its ability to transmit information.Here,we realize the robust far-field orbital angular momentum(OAM)transmission and detection by modulating the spatial-coherence structure of a partially coherent vortex beam with the help of the cross-phase.The cross-phase enables the OAM information,quantified by the topological charge,hidden in the spatial-coherence structure can be stably transmitted to the far field and can resist the influence of obstructions and turbulence within the communication link.This is due to the self-reconstruction property of the spatial-coherence structure embedded with the cross-phase.We demonstrate experimentally that the topological charge information can be recognized well by measuring the spatial-coherence structure in the far field,exhibiting a set of distinct and separated dark rings even under amplitude and phase perturbations.Our findings open a door for robust optical signal transmission through the complex environment and may find application in optical communication through a turbulent atmosphere.

Clinical,Laboratory and Imaging Features of High Altitude Pulmonary Edema in Tibetan Plateau

Objective To analyze characteristics of high altitude pulmonary edema(HAPE)in Chinese patients.Methods We performed a retrospective study of 98 patients with HAPE.We reviewed the medical records and summarized the clinical,laboratory and imaging characteristics of these cases,and compared the results on admission with those determined before discharge.Results Forty-eight(49.0%)patients developed HAPE at the altitude of 2800 m to 3000 m.Ninty-five(96.9%)patients were man.Moist rales were audible from the both lungs,and moist rales over the right lung were clearer than those over the left lung in fourteen patients.The white blood cells[(12.83±5.55)versus(8.95±3.23)×109/L,P=0.001)]as well as neutrophil counts[(11.34±3.81)versus(7.49±2.83)×109/L,P=0.001)]were higher,whereas the counts of other subsets of white blood cells were lower on admission than those after recovery(all P<0.05).Serum levels of alkaline phosphatase(115.8±37.6 versus 85.7±32.4 mmol/L,P=0.020),cholinesterase(7226.2±1631.8 versus 6285.3±1693.3 mmol/L,P=0.040),creatinine(85.2±17.1 versus 75.1±12.8 mmol/L,P=0.021),uric acid(401.9±114.2 versus 326.0±154.3 mmol/L,P=0.041),and uric glucose(7.20±1.10 versus 5.51±1.11 mmol/L,P=0.001)were higher,but carbondioxide combining power(CO2CP,26.7±4.4 versus 28.9±4.5 mmol/L,P=0.042)and serous calcium(2.32±0.13 versus 2.41±0.10 mmol/L,P=0.006)were lower on admission.Arterial blood gas results showed hypoxemia and respiratory alkalosis on admission.Conclusions In the present research,men were more susceptible to HAPE than women,and in the process of HAPE,the lesions of the right lung were more serious than those of the left lung.Some indicators of routine blood test and blood biochemistry of HAPE patients changed.

Microbial diversity in two cold springs on the Qinghai-Tibetan Plateau

The microbial diversity in Wuli Area, Qinghai-Tibetan Plateau was investigated using 16S rRNA gene phylogenetic analyses. A total of 117 bacterial and 66 archaeal 16S rRNA gene clones were obtained from the Wuli cold springs, The bacterial clones could be classified into Proteobacteria, Acid- obacteria, Deinococci, Sphingobacteria, Flavobacteria, Nitrospirae, Actinobacteria, Gemmatimona- detes, and unclassified-bacteria; and the archaeal clones could be classified into Crenarchaeota and Thaumarchaeota. Among the major groups, Proteobacteria and Crenarchaeota were dominant in the bacterial and archaeal 16S rRNA gene clone libraries, respectively. The clone sequences obtained in Wuli cold springs were closely related to those from cold habitats, such as snow/ice/soils on high mountains or at high latitude. Especially, the microbial community composition of Wuli Area was more similar to that in Tibetan glaciers than cold environments of other locations. The data presented in this study have impli- cations for a better understanding of microbial diversity in cold springs on the Qinghai-Tibetan Plateau.

微生物修复石油烃土壤污染技术研究进展

随着人民生活水平的提高,环境保护问题愈发受到人们重视。其中石油烃的土壤污染因其持续时间长、污染去除难度大而受到广泛关注。在各类修复技术中,原位微生物修复强化技术因其成本较低、环境影响小、无二次污染、可原位修复的特点成为了当前的技术热门。文中综述了生物投加法、生物刺激法、联合修复法等原位微生物修复技术,并介绍了一些典型工程案例,为原位微生物修复强化技术的选择及工程应用提供了参考,并对未来原位微生物修复强化技术的研究重点进行了展望。

Ultra-compact titanium dioxide micro-ring resonators with sub-10-μm radius for on-chip photonics

Microring resonators (MRRs) with ultracompact footprints are preferred for enhancing the light-matter interactions to benefit various applications. Here,ultracompact titanium dioxide (TiO2) MRRs with sub-10-μm radii are experimentally demonstrated. Thanks to the large refractive index of TiO_(2),the quality factors up to -7.9×10^(4) and -4.4×10^(4)are achieved for TiO_(2) MRRs with radii of 10μm and 6μm,respectively,which result in large nonlinear power enhancement factors (>113) and large Purcell factors (>56). The four-wave mixing(FWM) measurements indicate that,compared to the large MRR,the FWM conversion efficiency of the ultracompact TiO2 MRRs can be greatly improved (e.g.,-25 dB versus-31 dB),a harbinger of significant superiorities. Demonstrations in this work provide more arguments for the TiO_(2) waveguides as a promising platform for various on-chip photonic devices.