As one of the most ubiquitous bulk reagents available, intrinsic chemical inertness tetrahydrofuran (THF) makes direct and site-selective C(sp3 )-H bond activation difficult, especially under redox neutral condition. Here, we demonstrate that semiconductor quantum dots (QDs) can activate α-C-H THF via forming QDs/THF conjugates. Under visible light irradiation, resultant alkoxyalkyl radical directly engages in cross-coupling with α-amino from amino C-H bonds or addition alkene...

Recovering molecular information remains a grand challenge in the widely used holographic and computational imaging technologies. To address this challenge, we developed mid-infrared photothermal microscope, termed Bond-selective Intensity Diffraction Tomography (BS-IDT). Based on low-cost brightfield microscope with an add-on pulsed light source, BS-IDT recovers both infrared spectra bond-selective 3D refractive index maps from intensity-only measurements. High-fidelity fingerprint...

The construction of substituted indole skeletons is always an important concern synthetic chemists because its prevalent structure found in natural products and biological molecules. Here, we succeeded preparing indoles their derivatives from a wide variety simple enamines via radical cyclization only with catalytic amounts iridium(III) photosensitizer (PS) DMSO solution under air atmosphere. mechanistic investigation suggests that the reaction involves course to accomplish conversion...

This paper examines the concept of power spaces across various disciplines, including architectural design and urban development, to understand how spatial environments influence dynamics social interactions. It introduces “Boundary-Domain” theory as a key framework for analyzing role physical boundaries in shaping specific domains. The study highlights interplay between domains can either foster segregation or enhance connectivity, providing insights addressing challenges modern contexts.

A unified strategy for the synthesis of 2-vinyl heterocycles is reported. With visible light irradiation, simple and cheap CuCl able to functionalize a terminal alkyne, giving Cu(I)-acetylide in situ. Unlike case noble metals or organic dye photocatalysts, this critical not only activates C-H bond alkynes but also serves as photocatalyst achieve varieties good excellent yields, even large scale late-stage functionalization natural product.

A long distance high resolution frequency-modulated continuous wave (FMCW) laser rangefinder with phase noise compensation and two-dimensional (2D) data processing skills is developed. Range-finding ladar consists of a continuously chirped source, an auxiliary reference interferometer, monostatic optical transceiver for target illumination return photon collection. To extend the range unambiguity lower electronic bandwidth, two-step frequency chirping scheme adopted, where pulse width, small...

Reported herein is the first example of C(sp)-H/Si-H cross-coupling by photocatalysis. In terms cheap and readily available starting materials, a series alkynylsilanes are prepared in good to excellent yields upon visible-light irradiation CuCl alkynes with silane. The large scale reaction flow chemistry late-stage functionalization natural products shows potential transformation practical organic synthesis intermediates.

A novel and high-efficiency linear frequency-modulated continuous-wave (FMCW) ladar system for synthetic aperture imaging is proposed experimentally demonstrated. This generates wide-bandwidth FMCW signals by employing an electro-optic LiNbO3- in-phase quadrature modulator with effective bias controller. The effectiveness of the validated. Optical images are obtained using two 0.41 cm diameter telescopes at distance 1 km. resolution these can reach to 4 cm. improvement about 10 times...

Abstract As one of the most ubiquitous bulk reagents available, intrinsic chemical inertness tetrahydrofuran (THF) makes direct and site‐selective C(sp 3 )−H bond activation difficult, especially under redox neutral condition. Here, we demonstrate that semiconductor quantum dots (QDs) can activate α‐C−H THF via forming QDs/THF conjugates. Under visible light irradiation, resultant alkoxyalkyl radical directly engages in cross‐coupling with α‐amino from amino C−H bonds or addition alkene...

Experimental research is performed on a phase noise compensation (PNC) method to improve the signal-to-noise ratio of frequency modulated continuous wave (FMCW) ladar under long-distance-detection and atmospheric propagation conditions. In PNC method, local self-coherent reference generated where laser source recorded. Then long-distance-target echo can be compensated by mean recorded noise. The chirped from 1550-nm seed laser, whose bandwidth 10 GHz. experiments, target for test an optical...

A new autofocus method of the space-time-varied phase error (PE) correction is presented for inverse synthetic aperture ladar (ISAL). The PE corrected by a two-dimension matrix that estimated in form gradient both frequency and time domains. we named as PGMA capable compensating non-parametrical motion errors varying from pulse to robust widespread scene contents where any isolated strong scatterer not necessary. effectiveness verified comparing imaging results extended targets between...

In ballistic missile defense, using precession parameters is an effective way to determine warheads from decoys. Due the geometric theory of diffraction, backscattered field a smooth object for microwave radar consists contributions only isolated scattering centers. Further, thanks short wavelength laser, ladar could obtain complete Doppler information illuminated parts precessing targets. On basis modeling observation geometry rotating target with precession, novel method extracting...

As an important imaging method for long-range satellite targets, inverse synthetic aperture ladar (ISAL) has the characteristics of high-resolution and competitive detectability. Since working wavelength ISAL is comparable to micro-vibrations generated by mechanical moving components satellites, which will cause image defocusing, motion compensation great significance. In this paper, autofocus algorithm proposed estimating compensating phase error relating both translational rotational...

In space defense, utilizing the micromotion features to distinguish real targets from interfering and decoys is effective. Due imaging of high-speed precession target by microwave radar consisting isolated scattering centers, there are many difficulties in using inverse synthetic aperture (ISAR) images for feature extraction. On other hand, ladar (ISAL) image relatively continuous because short wavelength laser, sequence contains information about variation length Doppler width caused...

Doppler tomography is an important means to obtain two-dimensional (2-D) images of remote targets. It especially suitable for imaging spinning targets such as space debris, warheads, and aircraft blades. However, related research mostly focused on the microwave band rather than laser. Higher resolution can be achieved by implementing in laser compared existing microwave. Moreover, methods are directed at point When these deal with extended target echoes, image quality unsatisfactory. These...

The micro‐motion feature extraction of precession target is an effective way for discriminating warhead from decoy in missile ballistic defence. Generally, traditional methods based on high‐resolution range profile (HRRP) sequences put forward high requirements modulation bandwidth the system, increasing complexity system significantly. Utilising single‐frequency ladar without modulation, authors proposed a parameter algorithm Doppler (HRDP) sequences. Firstly, they model cone‐shaped with...

Inverse Synthetic Aperture Ladar (ISAL) can continuously capture images of the target in complex motion, which provides an opportunity for 3-D reconstruction. However, existing imaging methods need to meet some specific conditions, including multiple isolated prominent scattering points image, known or parametric motion target, and 360° observation target. To relax these restrictions, a novel reconstruction method is proposed. In this method, corner first detected used as reference point....

Inverse Synthetic Aperture LADAR (ISAL) can obtain high resolution images of remote targets. In order to measure the dimension target, ISAL image must be scaled. Many existing scaling methods require isolated strong scattering centers which are not easily found in images. To solve this problem, a novel method is proposed. The estimates Doppler frequency modulation rate each range row by fractional Fourier transform (FrFT) and entropy. linear relationship between used an estimate target...

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Volumetric chemical imaging is highly desired for investigating biochemical processes at the sub-cellular level. Here, we report bond-selective intensity diffraction tomography (BS-IDT) based on 3D quantitative phase detection of mid-infrared photothermal effect. BS-IDT demonstrates volumetric with incoherent diffraction-limited resolution and a high speed up to ~6 Hz per volume. The mid-IR spectrum extracted from shows fidelity compared ground truth measured by an FTIR spectrometer. results...

To solve the problems that traditional artificial potential field (APF) is easy to fall into minimum trap in process of three-dimensional path planning and A * algorithm inefficient, an APF -A fusion search proposed. Firstly, order avoid unmanned aerial vehicle (UA V) falling algorithm, added algorithm. After method falls trap, used continue searching path, so as escape from point find target point. Secondly, speed will affect overall efficiency. by reasonably set virtual points, can be...