Mixed-cation perovskite solar cells in space

<正>The metal halide perovskite materials demonstrate outstanding performance in photovoltaics because of their excellent optoelectronic properties [1-7]. The perovskite solar cells (PSCs) exhibiting outstanding efficiency [8,9], high power-per-weight [10], and excellent radiation resistance[11-13] are considered to be promising for developing the new-generation energy technology for space application.However, the extreme space environment would impose     

无处不在的化学——化学动力学

Starting from an example of how to extinguish a fire, this article illustrates how chemical dynamics plays a role in our life. It also introduces what is chemical dynamics and the contribution of Dutch chemist Jacobus H. van't Hoff to chemical dynamics. The horse racing analogy is used to illustrate how the amount of reactants, energy, catalysts and other factors affect the chemical reaction rate.     

多孔TiO2负载Pt的制备及室温下催化降解甲醛的研究

以钛酸丁酯为前驱物,通过水解-水热法,成功制备了多孔TiO2,以此为载体,通过化学还原法负载Pt,制得Pt/TiO2复合催化剂.采用XRD、SEM、TEM、N2吸附-脱附等方法对样品的理化性能进行表征,以HCHO为目标污染物,测试了Pt/TiO2催化剂的室温催化活性.实验结果表明:水热处理对样品的微观结构和催化活性有很大影响,水热处理有助于TiO2晶体化,形成层次丰富和形状规则的孔道体系,有助于Pt的分散负载和污染物分子的扩散流通.以多孔TiO2作为载体的催化剂比以P25作为载体的催化剂具有更高的催化活性,多次循环测试,Pt/TiO2催化剂仍具有较高的稳定性.     

Natural convection heat transfer at reduced pressures

This paper experimentally studies the natural convection heat transfer characteristics on horizontal and vertical plates at pressures lower than atmospheric value. Eight different pressures ranging from 10Pa to 101.325kPa, and three heating loads were used in the experiments. It is found that natural convection heat transfer characteristics at reduced pressures are independent of the plate arrangements and present different behaviors in two pressure ranges, 10Pa < p < 1000Pa and p > 1000Pa. The experimental heat transfer results are correlated into a non-dimensional equation to help the thermal design of stratosphere aircrafts and airborne equipment.     

An LC–MS/MS method for quantification of HR011303, a novel highly selective urate transporter 1 inhibitor in beagle dogs and the application to a pharmacokinetic study

HR011303 is a novel and highly selective urate transporter 1 (URAT1) inhibitor. In this study, a sensitive liquid chromatography–tandem mass spectrometry (LC–MS/MS) method was developed and validated for quantification of HR011303 in beagle dog plasma. Plasma samples were pretreated with protein‐precipitation extraction by acetonitrile and added with a trifluoromethyl substituted analog of HR011303 as internal standard. The chromatographic separation was performed on a Shiseido C₁₈ column (100 × 4.6 mm, i.d., 5 μm) by mobile phases consisting of 5 mm ammonium–formic acid (100:0.1) and acetonitrile–formic acid (100:0.1) solutions in gradient elution. The MS detection was conducted in electrospray positive ionization with multiple reactions monitoring at m/z 338 → 240 for HR011303 and m/z 328 → 230 for the internal standard using 25 eV argon gas collision induced dissociation. The established LC–MS/MS method showed good selectivity, sensitivity, precision and accuracy. The plasma pharmacokinetics of HR011303 in beagle dogs following both oral and intravenous administration were then successfully evaluated using this LC–MS/MS method.     

Quantitative ultra‐high‐performance liquid chromatography–tandem mass spectrometry for determination of dexmedetomidine in pediatric plasma samples: Correlation with genetic polymorphisms

Dexmedetomidine is an important sedative agent administered as premedication to achieve procedural sedation in children. To describe the correlation between the genetic state and the concentration of dexmedetomidine, it is necessary to develop a specific, time‐saving and economical method for detection of dexmedetomidine in plasma samples. In this work, an ultra‐high‐performance liquid chromatography (UHPLC)–tandem mass spectrometry method has been established and validated for detection of dexmedetomidine in plasma from pediatric population. After a simple liquid–liquid extraction with an organic solution, the analytes were separated on an ACQUITY BEH C₁₈ column (2.1 mm × 50 mm, 1.7 μm particle size) by gradient elution with the mobile phase of acetonitrile and 1‰ aqueous formic acid (flow rate 0.3 mL min^?1). Mass spectrometry measurements were performed under the positive selected reaction monitoring and the mass transitions monitored were m/z 201.3 → 95.1, 204.2 → 98.0 for dexmedetomidine and deuterated medetomidine (internal standard), respectively. Validation of the method based on China Food and Drug Administration guidelines showed acceptable selectivity. The UHPLC method employed a stable isotope‐labeled internal standard, showed good specificity and was successfully used to detect dexmedetomidine in plasma samples from 260 pediatric patients. A subsequent application of this method to a pharmacogenetic study was also described. Importantly, this is the first study to report the correlation between CYP2A6 rs835309 activity and concentration of dexmedetomidine.     

Stereoselective Synthesis of Trisubstituted Vinylboronates from Ketone Enolates Triggered by 1,3‐Metalate Rearrangement of Lithium Enolates

An unprecedented stereoselective synthesis of trisubstituted vinylboronates is reported to proceed by direct borylation of lithium ketone enolates under transition‐metal‐free conditions. The stereospecific C?O borylation of lithium enolates was triggered by a carbonyl‐induced 1,3‐metalate rearrangement via a C‐bound boron enolate. DFT calculations and control experiments revealed that the stereoselectivity is controlled by sterics. A variety of stereospecific trisubstituted vinylboronates, together with several tetrasubstituted vinylboronates, were conveniently synthesized with the newly developed methodology. Based on the transformation of stereospecific vinylboronate, a single isomer of Dienestrol was efficiently obtained.     

Metal–Organic Framework (MOF) Template Based Efficient Pt/ZrO2@C Catalysts for Selective Catalytic Reduction of H2 Below 90 °C

Selective catalytic reduction (SCR) of NO_x with H₂ as a reductant is the most promising denitration technology at low temperature. Achieving the conversion of NO_x into N₂ at ambient temperature not only prolongs the service life of the catalyst, but also provides more freedom for the arrangement of denitration units throughout the flue gas treatment equipment. However, the development of highly efficient, stable, and environmentally benign supported platinum‐based catalysts for H₂‐SCR at ambient temperature is still a major challenge. Herein, a 0.5 wt % Pt/ZrO₂@C catalyst, which was composed of carbon‐coated octahedral ZrO₂ with highly dispersed Pt particles, was prepared by using a new stabilization strategy based on UiO‐66‐NH₂ (a zirconium metal–organic framework) as a template. The catalytic performance of this Pt/ZrO₂@C in H₂‐SCR was tested and confirmed to achieve near 100 % NO_x conversion at 90 °C. Also, 70 % N₂ selectivity of the catalyst was achieved. The morphology, structure, and porous properties of the as‐synthesized nanocomposites were characterized by using data obtained from field‐emission SEM, TEM, XRD, Raman spectroscopy, thermogravimetric analysis, X‐ray photoelectron spectroscopy, and N₂ adsorption–desorption isotherms. The results show that residual carbon formed by pyrolysis treatment is coated on octahedral ZrO₂, and effectively prevents the agglomeration of platinum particles on the surface.     

Progress of organic magnetic materials

Over the past years, the development of magnetic materials has been intensively explored, both for fundamental research and technological applications. Particularly, several materials with large magnetoresistance effect have received significant interest.In this study, we provide an analysis of the progress of organic magnetic materials and organic magnetoelectric complexes, thus paving the way for the understanding of organic magnetism and magnetoelectric coupling mechanisms. In addition, this analysis provides us a critical guide for future organic magnetic material design and fabrication.