α-Al_2O_3比表面积标准物质的研制

选择市售α-Al2O3粉体作为比表面积标准物质候选材料,采用交叉缩分方法对标准物质样品进行分装。检验结果表明α-Al2O3标准物质样品具有良好的均匀性和稳定性(18个月)。采用国际公认的氮气物理吸附BET方法,联合测量能力经过确认的8家实验室对α-Al2O3标准物质样品进行定值,标准值比表面积为5.47 m2/g,不确定度为0.22 m2/g(k=2)。     

Efficient and Stable Thin-Film Luminescent Solar Concentrators Enabled by Near-Infrared Emission Perovskite Nanocrystals

A novel triphenylphosphine (TPP) treatment strategy was developed to prepare the near-infrared emission CsPbI₃ nanocrystal (NC)-polymer composite thin-film luminescent solar concentrators (LSCs) featuring high absolute photoluminescence quantum yield (PLQY), low reabsorption, and high stability. The PL emission of the LSCs is centered at about 700 nm with 99.4±0.4 % PLQY and narrow full width at half maximum (FWHM) of 75 meV (30 nm). Compared with LSCs prepared with classic CsPbI₃ NCs, the stability of the LSCs after TPP treatments has been greatly improved, even after long-term (30 days) immersion in water and strong mercury-lamp irradiation (50 mW cm⁻²). Owing to the presence of lone-pair electrons on the phosphorus atom, TPP is also used as a photoinitiator, with higher efficiency than other common photoinitiators. Large-area (ca. 75 cm²) infrared LSCs were achieved with a high optical conversion efficiency of 3.1 % at a geometric factor of 10.     

浅谈制药工程专业有机化学实验教学的心得和体会——以三苯甲醇的制备和重结晶实验为例

有机化学实验是制药工程专业的一门必修课,旨在训练学生有机合成基本实验技能。本文以三苯甲醇的制备和重结晶实验为例,讲述了笔者在多年教学中获得的一点感悟和经验:1)将实验步骤分解成片断讲解可以使学生更好地理解和记忆实验过程和操作目的;2)重要的基本操作应反复练习,即"学习、复习、提高",通过三次重复练习来实现巩固和熟练掌握该操作的目的。     

高分辨电感耦合等离子体磁质谱法测定含铜不锈钢中痕量磷

作者通过试验,用电感耦合等离子体磁质谱(HR-ICP-MS)测定含铜不锈钢中磷含量时,采用高分辨率模式,选择分辨率为4000,在此条件下磷峰可与干扰双原子分子或离子的峰分开。又通过以含铁基的磷标准溶液优化了气体流量和离子透镜的参数,使磷的信号值提高至3×105cps。而加入45Sc作为内标元素又可显著提高测定的稳定性。分别用不锈钢样品和纯铁粉作基体,加入标准溶液制作标准曲线。结果表明:两种方法的线性均较好,分别测得实际样品的结果及其相对标准偏差也基本一致。但两种方法的检出限(3s)不同,前者为1.0μg·g^-1,后者为0.18μg·g^-1。所提出方法的样品处理过程如下:称取样品0.10g置于消解罐中,加入盐酸溶液2mL及硝酸溶液1mL,待剧烈反应缓解时,将消解罐加盖并置于微波消解仪中,于100℃消解10min,升温至200℃继续消解20min。冷却后将溶液转移至100 mL石英容量瓶中,加入0.2mg·L^-1钪内标溶液1mL,加水至刻度,摇匀。此溶液在仪器工作条件下进行HR-ICP-MS测定。对含磷51μg·g^-1的含铜不锈钢,按本方法测定所得结果的相对标准偏差(n=10)小于4%。应用本方法分析了7种标准物质或已知样品(包括低合金钢、含铜不锈钢、高温合金),并同时用ICP-AES进行校对分析。结果表明,本方法与ICP-AES的测定结果基本一致。但本方法的结果与标准物质的认定值更接近,而且对低含量磷(9μg·g^-1)也可很好测定。     

High-refractive index acrylate polymers for applications in nanoimprint lithography

The development of polymeric optical materials with a higher refractive index,transparency in the visible spectrum region and easier processability is increasingly desirable for advanced optical applications such as microlenses,image sensors,and organic light-emitting diodes.Most acrylates have a low refractive index(around 1.50)which does not meet the high perfo rmance requirements of advanced optical materials.In this research,three novel acrylates were synthesized via a facile one-step approach and used to fabricate optical transparent polymers.All of the polymers reveal good optical properties including high transparency(≥90%)in the visible spectrum region and high refractive index values(1.6363)at 550 nm.Moreover,nanostructures of these acrylate polymers with various feature sizes including nanogratings and photonic crystals were successfully fabricated using nanoimprint lithography.These results indicate that these acrylates can be used in a wide range of optical and optoelectronic devices where nanopatterned films with high refractive index and transparency are required.     

Responsive Exosome Nano‐bioconjugates for Synergistic Cancer Therapy

Exosomes hold great potential in therapeutic development. However, native exosomes usually induce insufficient effects in vivo and simply act as drug delivery vehicles. Herein, we synthesize responsive exosome nano‐bioconjugates for cancer therapy. Azide‐modified exosomes derived from M1 macrophages are conjugated with dibenzocyclooctyne‐modified antibodies of CD47 and SIRPα (aCD47 and aSIRPα) through pH‐sensitive linkers. After systemic administration, the nano‐bioconjugates can actively target tumors through the specific recognition between aCD47 and CD47 on the tumor cell surface. In the acidic tumor microenvironment, the benzoic‐imine bonds of the nano‐bioconjugates are cleaved to release aSIRPα and aCD47 that can, respectively, block SIRPα on macrophages and CD47, leading to abolished “don't eat me” signaling and improved phagocytosis of macrophages. Meanwhile, the native M1 exosomes effectively reprogram the macrophages from pro‐tumoral M2 to anti‐tumoral M1.     

Three‐Pronged Attack by Homologous Far‐red/NIR AIEgens to Achieve 1+1+1>3 Synergistic Enhanced Photodynamic Therapy

Photodynamic therapy (PDT) has long been shown to be a powerful therapeutic modality for cancer. However, PDT is undiversified and has become stereotyped in recent years. Exploration of distinctive PDT methods is thus highly in demand but remains a severe challenge. Herein, an unprecedented 1+1+1>3 synergistic strategy is proposed and validated for the first time. Three homologous luminogens with aggregation‐induced emission (AIE) characteristics were rationally designed based on a simple backbone. Through slight structural tuning, these far‐red/near‐infrared AIE luminogens are capable of specifically anchoring to mitochondria, cell membrane, and lysosome, and effectively generating reactive oxygen species (ROS). Notably, biological studies demonstrated combined usage of three AIE photosensitizers gives multiple ROS sources simultaneously derived from several organelles, which gives superior therapeutic effect than that from a single organelle at the same photosensitizers concentration. This strategy is conceptually and operationally simple, providing an innovative approach and renewed awareness of improving therapeutic effect through three‐pronged PDT.     

Recent advances of ambient ionization mass spectrometry imaging in clinical research

The structural information and spatial distribution of molecules in biological tissues are closely related to the potential molecular mechanisms of disease origin, transfer, and classification. Ambient ionization mass spectrometry imaging is an effective tool that provides molecular images while describing in situ information of biomolecules in complex samples, in which ionization occurs at atmospheric pressure with the samples being analyzed in the native state. Ambient ionization mass spectrometry imaging can directly analyze tissue samples at a fairly high resolution to obtain molecules in situ information on the tissue surface to identify pathological features associated with a disease, resulting in the wide applications in pharmacy, food science, botanical research, and especially clinical research. Herein, novel ambient ionization techniques, such as techniques based on spray and solid‐liquid extraction, techniques based on plasma desorption, techniques based on laser desorption ablation, and techniques based on acoustic desorption were introduced, and the data processing of ambient ionization mass spectrometry imaging was briefly reviewed. Besides, we also highlight recent applications of this imaging technology in clinical researches and discuss the challenges in this imaging technology and the perspectives on the future of the clinical research.     

Rate-dependent asymmetric hysteresis modeling and robust adaptive trajectory tracking for piezoelectric micropositioning stages

Nonlinear Dynamics - Hysteresis is an inherent characteristic of piezoelectric materials that can be determined by not only the historical input but also the input signal frequency. Hysteresis...     

含钒杂多酸催化发烟硫酸中甲烷液相部分氧化反应

 以H5PV2Mo10O40 为催化剂,在发烟硫酸中进行了甲烷液相部分氧化,考察了催化剂用量、反应温度、反应时间和发烟硫酸浓度等工艺条件对反应收率的影响. 甲烷在反应中首先转化为硫酸甲酯,硫酸甲酯随后水解为甲醇. 对于甲烷液相部分氧化反应,发烟硫酸中游离的SO3是非常重要的影响因素. 在工艺条件为催化剂用量7.0 mmol, 反应温度473 K, 反应压力3.5 MPa, 反应时间3 h和发烟硫酸中SO3含量50%时,甲烷转化率可达48.5%, 目的产物甲醇收率为41.5%.