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Herein, a novel one pot synthesis of chiral δ-substituent caprolactam strategy which applies 1-substituent homoallylic amine as the starting material is reported. This method combines the enzymatic dynamic kinetic resolution (DKR) and ring cross metathesis. Moreover, the configuration of caprolactam can be controlled by using lipase and protease as the DKR catalyst. The enantiomeric excess value of obtained R- and S-caprolactam can reach up to 90% and 82%, the yield can also be above 82% and 70%.(报道了一种以1-取代高烯丙基胺为原料，结合酶催化动态动力学拆分与分子内烯烃复分解反应串联一锅法制备手性δ-取代己内酰胺的方法。分别用脂肪酶和蛋白酶作为动态动力学拆分催化剂，实现了手性δ-取代己内酰胺立体构型的调控。通过该方法制备的R-δ-取代己内酰胺的对映体过量值（enantiomeric excess，ee）均在90%以上，产率维持在76%以上；所制备的S-δ-取代己内酰胺的ee也在82%以上，产率均高于70%。)

As an alternative technology to energy intensive distillations, adsorptive separation by porous solids offers lower energy cost and higher efficiency. Herein we report a topology-directed design and synthesis of a series of Zr-based metal-organic frameworks with optimized pore structure for efficient separation of C6 alkane isomers, a critical step in the petroleum refining process to produce gasoline with high octane rating. Zr6O4(OH)4(bptc)3 adsorbs a large amount of n-hexane but excluding branched isomers. The n-hexane uptake is ~70% higher than that of a benchmark adsorbent, zeolite-5A. A derivative structure, Zr6O4(OH)8(H2O)4(abtc)2, is capable of discriminating all three C6 isomers and yielding a high separation factor for 3-methylpentane over 2,3-dimethylbutane. This property is critical for producing gasoline with further improved quality. Multicomponent breakthrough experiments provide a quantitative measure of the capability of these materials for separation of C6 alkane isomers. A detailed structural analysis reveals the unique topology, connectivity and relationship of these compounds.

Porous metal-organic framework (MOF) materials with high thermal and water stability are desirable for various adsorption based applications. Early transition metal based MOFs such as those built on zirconium metal have been well recognized for their excellent stability toward heat and/or moisture. However, the difficulty growing large single crystals makes their structural characterization challenging. Herein we report a porous Zr-MOF, [Zr6O4(OH)4(cca)6] (Zr-cca), which is assembled from zirconium and 4-carboxycinnamic acid (H2cca) under solvothermal conditions. Single crystal X-ray diffraction analysis reveals that the structure of Zr-cca is isoreticular to the prototype zirconium based MOF, UiO-66. Zr-cca shows permanent porosity upon removal of solvent molecules initially residing inside the pores, with a BET surface area of 1178 m2/g. As expected, it exhibits good thermal stability (stable up to 400 °C) and high resistance to acidity over a wide pH range. Evaluation of its gas adsorption performance on various hydrocarbons and fluorocarbons indicates that it preferentially adsorbs C3 and C4 hydrocarbons over C2 analogues. At 30 °C Zr-cca takes up more than 50 wt % of perfluorohexane and the adsorption-desorption process is fully recyclable. We have compared this material with UiO-66 and studied the underlying reasons for the difference in their adsorption performance toward perfluorohexane.

Photon‐to‐Photon latency indicates the time it takes for the device to transmit events captured from the real world to display of headset in real‐time, and this lag is 0 for AR, but is noticeable for MR that uses Video See‐Through. The industry‐leading product assert to deliver a PTP performance within a span of 12 milliseconds. Therefore, high‐precision equipment is required for testing. We have developed a PTP test equipment that can achieve a test accuracy of 0.08ms. With such an approach, we discovered that a range of commercially available products vary in their performance levels, while the top‐performing product offers a PTP latency of less than 10ms. In addition, our method can avoid the influence of motion blur from the VST camera and can test the PTP latency performance of the system for a long time and with high accuracy. At the same time, different testing methods are customized for different users, such as product developers and evaluation agencies. [ABSTRACT FROM AUTHOR]

During Fischer–Tropsch synthesis, O atoms are dissociated on the surface of Fe-based catalysts. However, most of the dissociated O would be removed as H2O or CO2, which results in a low atom economy. Hence, a comprehensive study of the O removal pathway as formic acid has been investigated using the combination of density functional theory (DFT) and kinetic Monte Carlo (kMC) to improve the economics of Fischer–Tropsch synthesis on Fe-based catalysts. The results show that the optimal pathway for the removal of dissociated O as formic acid is the OH pathway, of which the effective barrier energy (0.936 eV) is close to that of the CO activation pathway (0.730 eV), meaning that the removal of dissociated O as formic acid is possible. The main factor in an inability to form formic acid is the competition between the formic acid formation pathway and other oxygenated compound formation pathways (H2O, CO2, methanol-formaldehyde); the details are as follows: 1. If the CO is hydrogenated first, then the subsequent reaction would be impossible due to its high effective Gibbs barrier energy. 2. If CO reacts first with O to become CO2, it is difficult for it to be hydrogenated further to become HCOOH because of the low adsorption energy of CO2. 3. When the CO + OH pathway is considered, OH would react easily with H atoms to form H2O due to the hydrogen coverage effect. Finally, the removal of dissociated O to formic acid is proposed via improving the catalyst to increase the CO2 adsorption energy or CO coverage. [ABSTRACT FROM AUTHOR]