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Achieving efficient multi-electron-involved photoreduction, e.g. the reduction of nitroaromatics to amines, remains challenging yet highly demanded. Two-dimensional (2D) covalent organic nanosheets (CONs) present promising platforms for such reactions due to their exceptional properties, including structural tunability and unique photoelectronic properties. Nevertheless, the exploration of CON-based composites for catalyzing organic reactions is still in its infancy, with examples of CONs acting as intrinsic catalysts being relatively scarce. In this study, we developed hybrid catalysts, denoted as T4-Mn/QA-CONs, by decorating anionic semiconductor clusters (T4-Mn) onto 2D cationic CONs (QA-CONs) via electrostatic self-assembly. Remarkably, T4-Mn/QA-CONs exhibited exceptional performance, achieving a 99% conversion rate and 100% selectivity with a turnover frequency (TOF) of 2.68 h−1 in the reduction of nitroarenes to amines under visible light irradiation. In addition, T4-Mn/QA-CONs demonstrated excellent stability and recyclability, along with remarkable functional group tolerance. The outstanding activity can be attributed to the effective charge separation facilitated by the photoinduced strong internal electric field and II-scheme mechanism, as confirmed by in situ X-ray photoelectron spectroscopy along with femtosecond transient absorption spectroscopy. This study presents a novel strategy for designing CONs as crucial catalytic centers and highlights the potential of CON-based heterojunction photocatalysts for efficient organic transformations. [ABSTRACT FROM AUTHOR]

Calf diarrhea is one of the main diseases affecting the growth and development of calves. Factors that cause diarrhea in calves include bacterial, viral, parasitic, and non-infectious factors. Bacterial diarrhea is one of the common causes of diarrhea in calves, and its mechanism is mainly due to the proliferation of bacteria after entering the intestine, destroying the balance of intestinal flora, and then causing serious damage to the intestinal mucosal barrier of calves. Chinese herbal medicine has the effect of regulating the intestinal flora, enhancing immune function, and reducing the diarrhea rate of calves. This article reviews the etiology of calf diarrhea and the research progress of Chinese herbal medicine treatment, so as to provide a reference for the clinical treatment of calf diarrhea. [ABSTRACT FROM AUTHOR]

The winter cold stress of dairy cows has become one of the important problems affecting the healthy development of animal husbandry. Cold stress will lead to the decrease of feed intake, milk yield and reproductive performance of dairy cows, and seriously harm the economic benefits of dairy farmers. Inner Mongolia is located in a cold region, where animals are in a cold environment for a long time, and the impact of cold stress is more common. In order to more specifically understand the effects of cold stress on the production performance of dairy cows, the paper reviews the effects of cold stress on the behavior, milk yield, neuroendocrine, biochemical indexes, immune, antioxidant function, intestinal flora and other aspects of dairy cows, and summarizes the effective prevention and control measures to prevent cold stress of dairy cows, to provide reference for further research on the prevention and relief of cold stress in dairy cows. [ABSTRACT FROM AUTHOR]

Mode switching between fuel cell and electrolytic mode is inevitable for actual applications. During the mode switching, complicated electrical response and gas-liquid phase change occur due to the different operation conditions in these two modes. To explore the effect of water removal method on electrical performance before fuel cell mode startup in mode switching process and get better overall cell performance. In this paper, the continuous mode switching within three cycles is explored by experimental works. It is found that the voltage decreases slightly with the cycle running, and the two-phase flow in the corresponding mode of each cycle is similar through analyzing the two-phase flow phenomenon of the two modes during mode switching. It is also found that bubbles are generated during electrolytic cell, the water is consumed and there is only water mist at the transparent end plate during electrolytic cell mode without water. A handful of liquid water gathers at the bottom of the flow channel during fuel cell mode. Experiments of the cycle test process are also conducted. It is shown that with the cell mode switching periodically, the cell voltages of the electrolytic cell and fuel cell both decrease periodically. The fuel cell performance changes more, especially under high current density. [ABSTRACT FROM AUTHOR]

In this work, we used time-sliced ion velocity imaging to study the photodissociation dynamics of MgO at 193 nm. Three dissociation pathways are found through the speed and angular distributions of magnesium. One pathway is the one-photon excitation of MgO(X1Σ+) to MgO(G1Π) followed by spin-orbit coupling between the G1Π, 33Π and 15Π states, and finally dissociated to the Mg(3Pu)+O(3Pg) along the 15Π surface. The other two pathways are one-photon absorption of MgO(A1Π) state to MgO(G1Π) and MgO(41Π) state to dissociate into Mg(3Pu)+O(3Pg) and Mg(1Sg)+O(1Sg), respectively. The anisotropy parameters of the dissociation pathways are related to the lifetime of the vibrational energy levels and the coupling of rotational and vibronic spin-orbit states. The total kinetic energy analysis gives D0(Mg−O)=21645±50 cm−1. [ABSTRACT FROM AUTHOR]

In the one-color experiment at 193 nm, we studied the photodissociation of Si2+ ions prepared by two-photon ionization using the time-sliced ion velocity map imaging method. The Si+ imaging study shows that Si2+ dissociation results in two distinct channels: Si(3Pg)+Si+(2Pu) and Si(1D2)+Si+(2Pu). The main channel Si(3Pg)+Si+(2Pu) is produced by the dissociation of the Si2+ ions in more than one energetically available excited electronic state, which are from the ionization of Si2(v=0−5). Particularly, the dissociation from the vibrationally excited Si2(v=1) shows the strongest signal. In contrast, the minor Si(1D2)+Si+(2Pu) channel is due to an avoided crossing between the two 2Πg states in the same symmetry. It has also been observed the one-photon dissociation of Si2+ (X 4 Σ g −) into Si(1D2)+Si+(2Pu) products with a large kinetic energy release. [ABSTRACT FROM AUTHOR]