The fluorescence properties of graphene oxide (GO) was studied by recording the fluorescence lifetime, fluorescence emission, and excitation spectra, as well as UV-visible and near-IR absorption spectra. For the first time, we showed that a blue band (ca. 440 nm) and a long wavelength (LW) band (ca. 700 nm) are coexistent, which can be recorded simultaneously by controlling concentration, excitation wavelength, and pH values. Two bands are closely related by the protonation or deprotonation of GO. The blue band is favored by low GO concentration, short excitation wavelength, and high pH value, while the LW band is favored by low pH and long excitation wavelength. To reveal the nature of the dual emission of GO, the fluorescence lifetimes under various conditions were also measured. The blue band contains three emitting components; one of them has a lifetime as long as 10 ns, and its emitting intensity is fairly sensitive to pH, showing the potential for applications in sensing H(+) and fluorescence lifetime imaging. Combining the results under various conditions, we conclude that the electronic transition for this component is very likely due to n-π* transition. The LW band contains two main emitting components (0.2 and 2.1 ns) that also appear in the blue band as minor contributors; the related emission is assigned to π-π* transition. In summary, GO emission is of broadband (300-1250 nm), long-lived, pH sensitive, and excitation wavelength dependent. This makes it easily tailored for versatile applications.

Vertical deformation can be revealed by various techniques such as precise leveling, satellite imagery, and extensometry. Despite considerable effort, recording detailed subsurface deformation using traditional extensometers remains challenging when attempting to detect localized deformation. Here we introduce distributed fiber optic sensing based on Brillouin scattering as a geophysical exploration method for imaging distributed profiles of vertical deformation. By examining fiber optic cable‐soil interaction we found a threshold in confining pressure to achieve a strong cable‐soil coupling, thus validating data collected from a borehole‐embedded fiber optic cable deployed in Shengze, southern Yangtze Delta, China. Clear‐cut strain profiles acquired from November 2014 to December 2016 allowed us to pinpoint where compaction or rebound was actively occurring and examine strain responses at various locations along the entire cable length. We suggest that distributed fiber optic sensing can complement with extensometry and remote sensing techniques for improved monitoring of vertical deformation.

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The primary circulation of atmospheric vortices, such as tropical cyclones and tornadoes, can be estimated from single-Doppler radar observations using the ground-based velocity track display (GBVTD) algorithm. The GBVTD algorithm has limitations in the following four areas: 1) distortion in the retrieved asymmetric wind fields, 2) a limited analysis domain, 3) the inability to resolve the cross-beam component of the mean wind, and 4) the inability to separate the asymmetric tangential and radial winds. This paper presents the generalized velocity track display (GVTD) algorithm, which eliminates the first two limitations inherent in the GBVTD technique and demonstrates the possibility of subjectively estimating the mean wind vector when its signature is visible beyond the influence of the vortex circulation. In this new paradigm, the GVTD algorithm fits the atmospheric vortex circulation to a new variable VdD/RT in a linear azimuth angle (θ′), rather than the Doppler velocity Vd in a nonlinear angle (ψ), which is used in GBVTD. Key vortex kinematic structures (e.g., mean wind, axisymmetric tangential wind, etc.) in the VdD/RT space simplify the interpretation of the radar signature and eliminate the geometric distortion inherent in the Vd display. This is a significant improvement in diagnosing vortex structures in both operations and research. The advantages of using VdD/RT are illustrated using analytical atmospheric vortices, and the properties are compared with GBVTD. The characteristics of the VdD/RT display of Typhoon Gladys (1994) can be approximated by a constant mean wind plus an axisymmetric vortex.

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Objective To determine the value of hysteroscopy for the diagnosis and treatment of traumatic intrauterine adhesions after induced abortion. Design A retrospective study of 365 patients. Setting Shanghai Institute of Planned Parenthood Research, the International Peaceful Maternity and Children Health Hospital, and the Shanghai First Maternity and Infant Health Hospital. Subjects 365 patients with traumatic intrauterine adhesions after induced abortions were included in the study, of whom 351 complained of amenorrhoea or hypomenorrhea before treatment, and 186 of whom wanted to have a child. Interventions In all the patients, the diagnoses and types of intrauterine adhesions were confirmed by hysteroscopy, and the adhesions were separated using micro scissors and biopsy forceps under hysteroscopic view. Most procedures were carried out with ultrasound monitoring. Results In 346 out of 365 patients (94.8%) intrauterine adhesions were released successfully after 1–4 episodes of surgery. Of the 351 patients with amenorrhoea or hypomenorrhea before treatment, 294 (83.76%) had normal or near‐normal regular menstruation after therapy. Of the 186 patients who wanted to have a child and were followed up for more than 12 months after the withdrawal of contraception, 156 (83.87%) had intrauterine pregnancies. Among these 156 patients, 145 had full‐term pregnancies, with three instances of retained placenta and one of placental implantation, and 11 had early spontaneous abortions. Conclusion Hysteroscopy is of great value in the diagnosis and treatment of intrauterine adhesions after induced abortions. Patients were managed with few complications after hysteroscopic lysis. Most patients regained their fertility and normal regular menstruation.

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