Abstract This study synthesized polydimethylsiloxane (PDMS)‐modified polyaspartate polyurea (PPPU) with different ratios, considering the practical performance requirements of underground water supply pipeline spray repair materials. The successful synthesis PPPU was confirmed using Fourier transform infrared spectrometer (FTIR) spectroscopy. influence ratio two components and content ‐aminopropyl terminated (APT‐PDMS) on drying time tensile coatings evaluated. Based this evaluation, a...

Isatin-derived ketimines undergo enantioselective alkynylation reactions in the presence of copper iodide and easily accessible guanidine-amides. The corresponding 3-alkynyl-3-aminooxyindoles are obtained up to 95% yield 96% ee. guanidine plays a role formation acetylide enantiodetermining step basic additive is excluded.

Abstract Asymmetric cascade double Michael additions to construct 2′‐substituted 3,3′‐spirooxindoles by using a chiral guanidine organocatalyst has been developed. A series of spirooxindole derivatives containing dihydrofuran or pyrrolidine subunits were obtained with good excellent diastereo‐ and enantioselectivities. The method showed great tolerance number aromatic aliphatic alkynones. strategy gave access the asymmetric synthesis (−)‐salacin for first time.

Adiabatic demagnetization refrigeration, which utilizes the magnetocaloric effect of magnetic refrigerants, stands as sole cooling technology capable achieving sub-Kelvin temperatures efficiently and reliably without relying on scarce 3He resources or gravity. However, current refrigerants encounter challenges such structural instability in vacuum under mild heating, along with small entropy change (-ΔSm) values, significantly limit their practical applications. Here a water-free...

Nucleophilic substitution of B–H is an important strategy for the synthesis carborane derivatives. Although intermolecular nucleophilic has been widely explored, intramolecular rarely reported. Herein, we synthesized a novel carborane-fused N-heteroaromatic through transition-metal-free reaction between carboranyl lithium and 2,3-dichloroquinoxaline. Two C–Cl substitutions one with were involved in this transformation. Instead most electron-deficient B(3)–H vertex, selectively occurred on...

A highly enantioselective and<italic>Z</italic>-selective dearomatization of β-naphthols with alkynones has been accomplished using a chiral<italic>N</italic>,<italic>N</italic>′-dioxide–Sc(OTf)₃complex excellent outcomes.

A facile Ag‐catalyzed intramolecular C–P bond formation reaction from easily accessible phosphine oxides has been developed. Several new heteroatoms fused π‐conjugated molecules were synthesized this procedure with their structures confirmed by X‐ray structure analyses.

<italic>N</italic>,<italic>N</italic>′-Dioxide-scandium(<sc>iii</sc>) complex catalyzed cyclopropanation and C–H insertion reaction between α-substituted vinyl ketones α-diazoesters in high yield enantioselectivity.

Fluorinated surfactants, especially those with long fluorocarbon chains (CxF2x+1, x > 7) like perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS), are used wildly in industrial household fields. As research results have shown that such chain surfactants seriously toxic, obviously persistent highly bioaccumulative the environment, it is an urgent requirement to develop novel alternatives of surfactants. In this work, a series nonionic fluorinated (FxCy-m) was synthesized by...

The spraying method offers the advantages of environmental protection, convenient construction, and cost-effectiveness, making it widely used in pipeline structure repair. Given complex service environment pipelines, there is an urgent demand for high-strength durable materials. To achieve this goal, a PVA fiber reinforced cement mortar material (PFCM) with high early strength, excellent impermeability stable acid corrosion resistance was developed through orthogonal test design. optimal...

A series of spiro-phosphonium compounds have been synthesized by copper-mediated coupling reaction phosphacyclic with alkynes. Their photophysical properties are tuned varying substituents and exhibit different luminescent colors from blue to green, finally, yellow. The fluorescence quantum efficiency diethyl spiro-xanthenebenzophosphole

New reactions of benzyl phosphine oxide/sulfide with oxalyl chloride are presented. The resulting reactive intermediates, acyl chloride-substituted chlorophosphonium ylides, capable undergoing esterification and Friedel-Crafts acylation reactions, ultimately yielding either methyl 2-(2-bromophenyl)-2-(diphenylphosphoryl)acetate or β-carbonyl-diarylphosphine oxide derivatives. Additionally, when an alkynyl group is contained in the ylide, intramolecular cyclization occurs, leading to formation a pair

A facile synthesis of 2-bromo-6-pyrrolylpyridine 4 was developed starting from acylation pyrrole with glutaric acid and TFAA. Suzuki cross-couplings arylboronic acids gave a variety novel 2-aryl-6-pyrrolylpyridines in excellent yields.

Weakly-supervised action localization aims to recognize and localize instancese in untrimmed videos with only video-level labels. Most existing models rely on multiple instance learning(MIL), where the predictions of unlabeled instances are supervised by classifying labeled bags. The MIL-based methods relatively well studied cogent performance achieved classification but not localization. Generally, they locate temporal regions overlook variations feature semantics. To address this problem,...

ABSTRACT The separation of rac‐o ‐chloromandelic acid 1 with enantiopure aryloxypropylamine via diastereomeric salt formation was investigated. ( R )‐ o , a key intermediate for the antithrombotic agent clopidogrel, obtained in 65% yield and 98% ee by Dutch resolution rac ‐ S )‐2‐hydroxyl‐3‐( p ‐chlorophenoxy) propylamine 5 as resolving ‐nitrophenoxy) 4 nucleation inhibitor. Chirality 24:1013–1017, 2012 . © Wiley Periodicals, Inc.

In our recent work, it is found that the error of image-based method significantly affected by overlap effects for polydisperse particles. This can be attributed to large and small particles having conflicting requirements optical lens parameters. Based on this point, a new measurement proposed in study. Specifically, measured are cut into several classes based their size range, every class one vision probe with appropriate Then, results combined get distribution particle property....

The current study aims to clarify how much the measurement results using image-based method are affected by two types of total overlaps in images. By ensuring homogeneous suspension particles and simultaneous optimization probe location, it has been proven that overall holdup as benchmark data is reasonable. In a bi-disperse particle system, larger particles, more significant effect large veiling small particles. maximal relative error nears 50%. poly-disperse heavily depends on veiled size....