Quantitative in‐line monitoring of solvent‐mediated polymorphic transformation of sulfamerazine by near‐infrared spectroscopy

Lee, Min&#x2010,Jeong,Seo, Da&#x2010,Young,Wang, In&#x2010,Chun,Chun, Nan&#x2010,Hee,Lee, Hea&#x2010,Eun,Jeong, Myung&#x2010,Yung,Kim, Woo&#x2010,Sik,Choi, Guang J. Wiley Subscription Services, Inc., A Wiley Company 2012 journal of pharmaceutical sciences Vol.101 No.4

<P><B>Abstract</B></P><P>The in‐line monitoring of pharmaceutical processes with high risk, such as crystallization, has been one of the most popular research topics in recent years. Sulfamerazine (SMZ), a well‐known sulfonamide antibacterial agent was investigated to examine the mechanism of polymorphic conversion by solvent‐mediated polymorphic transformation (SMPT). The primary purpose of this study is to monitor the polymorphic transformation through in‐line near‐infrared (NIR) measurements and concurrently interpret the whole process quantitatively with off‐line characterizations. Samples taken at every hour during SMPT were analyzed by X‐ray diffractometry (XRD) and differential scanning calorimetry (DSC). NIR spectra in the range of 7500–4900 cm<SUP>−1</SUP> were taken into account for multivariate analysis, which included partial least square (PLS) regression and principal component analysis (PCA). In brief, the form II content was estimated very accurately and reproducibly during the SMPT process not only by XRD but also by the DSC measurements. In addition, the form II content values were predicted very accurately by separate experiments at two designated time points. In a separate study, it was demonstrated that PCA could be employed to explain a complicated process such as SMPT mechanistically by several stages. © 2012 Wiley Periodicals, Inc. and the American Pharmacists Association J Pharm Sci 101:1578–1586, 2012</P>

Preparation and Characterization of Magnetic Cobalt Ferrites/SBA-15 Nanocomposite Adsorbents and the Removal of Methylene Blue

X. J. Chen,J. C. Xu,H. X. Jin,D. F. Jin,B. Hong,H. L. Ge,X. Q. Wang 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2017 NANO Vol.12 No.5

In this paper, ordered mesoporous SBA-15 silica was synthesized by the hydrothermal method, and then a series of CoFe2O4/SBA-15 nanocomposites were synthesized by a facile impregnation method. X-ray diffraction and N2 adsorption–desorption isotherms were used to characterize the microstructure and morphology of SBA-15 and CoFe2O4/SBA-15 nanocomposites. CoFe2O4 nanoparticles presented spinel phase structure and existed in the mesopores of SBA-15. The magnetic response of CoFe2O4/SBA-15 nanocomposites was characterized with vibrating sample magnetometer (VSM). The adsorption efficiency of CoFe2O4/SBA-15 nanocomposites for methylene blue increased firstly with the increasing CoFe2O4 content, and then decreased. Sample-2 (SBA-15: CoFe2O4 = 1: 0.1 in the precursor) not only presented the best adsorptive performance, but also could be separated and retrieved effectively by magnetic separation technique.

Fabrications and dielectric performances of novel composites: Calcium copper titanate / Polyvinylidene fluoride

Wang J.J.,Deng Q.J.,He Y.Y.,Feng Y.N.,Kang M.P.,Duan X.L.,Yang Y.L. 한국물리학회 2022 Current Applied Physics Vol.39 No.-

CCTO (Calcium copper titanate) powder as inorganic filler was synthesized by the Sol-gel method firstly. CCTO/ PVDF (Polyvinylidene fluoride) composite was fabricated by solution mixing based on high temperature resistance of PVDF and insulated property of CCTO. The composite of CCTO/PVDF were characterized by X-ray diffraction, Fourier Transform infrared spectroscopy, Scanning Electron Microscope and impedance analysis. The results showed that the addition of CCTO and increasing in its content did not affect the phase- and microstructure of the composites,but the increase of CCTO content can induce the generation of C–F new bonds. PVDF/CCTO composites were enhanced in performance of thermal and frequency-depended stability with increasing in the fraction of CCTO. The dielectric constant of CCTO/PVDF composite materials with 50% CCTO achieved to a maximum value of 50 almost, which is 5 times higher the pure PVDF. The conductivity felled into 10-8 to 10-1 S m-1 during the frequency of 102–108 Hz. The composite material would be expected to be applied in the field of integrated circuit.

Synthesis, structure and magnetic properties of ultra-high purity CrO₂ prepared under high O₂-gas pressure

Wang, X.L.,Si, P.Z.,Ge, H.L.,Shinde, K.P.,Chung, K.C.,Choi, C.J. Elsevier 2017 SOLID STATE SCIENCES Vol.67 No.-

<P><B>Abstract</B></P> <P>Ultra-high purity CrO<SUB>2</SUB> was prepared by decomposing CrO<SUB>3</SUB> in O<SUB>2</SUB> with gas pressures up to 40 MPa, which were maintained throughout the decomposition process of CrO<SUB>3</SUB> to prevent the formation of any other phases of chromium oxides. Our method is different from the traditional methods that start from or under ambient pressures. The high oxygen pressure makes the meta-stable CrO<SUB>2</SUB> stable from the initial stage of preparation. As a result, the purity of the as-prepared CrO<SUB>2</SUB> is improved, and this has been further proved by the highest magnetization of the samples. The as-prepared CrO<SUB>2</SUB> particles show very large grains with flat surfaces, octagonal cross-section, and straight edges, owing to the high mobility of Cr ions in CrO<SUB>2</SUB> at temperatures above its melting point. The lattice parameters of CrO<SUB>2</SUB> are <I>a</I> = 4.4176 Å and <I>c</I> = 2.9144 Å. The maximum value of the magnetic entropy change of the high purity CrO<SUB>2</SUB> particles is ∼2.83 J/kg·K for an applied field of 1.5 T. The preparation of pure CrO<SUB>2</SUB> is important for studying its intrinsic properties and for applications in spintronic devices.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Ultra-high purity CrO<SUB>2</SUB> was prepared. </LI> <LI> High O<SUB>2</SUB>-gas pressure was employed. </LI> <LI> The CrO<SUB>2</SUB> rods show straight edges and high magnetization. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Small Angle X-Ray Scattering Using Synchrotron Radiation Sources

X Wang,T J Shin,I J Lee,M Ree 한국고분자학회 1998 한국고분자학회 학술대회 연구논문 초록집 Vol.1998 No.10

Enhanced energy storage properties in PbZrO3 thin films via the incorporation of NiO

Wang X.W.,Chen J.Y.,Hu S.Y.,Yu K.X.,Yang F.,Shi Y.J.,Li J.H.,Hou M.Z.,Liu A.D.,Zheng M.M.,Yin S.Q.,Hu Y.C.,Shang J. 한국물리학회 2023 Current Applied Physics Vol.52 No.-

In this study, NiO–PbZrO3 composite films were deposited on SiO2/Si substrates buffered with LaNiO3 films via the sol-gel coating technique. The effects of NiO addition in PZO thin films on the microstructure, dielectric properties, leakage mechanism, ferroelectric properties and energy storage properties have been discussed. The dielectric constant increased with the addition of NiO, while the leakage current density decreased. Compared with pure PZO films, the maximum polarization of the composite films was improved. For the composite films prepared using the NiO precursor solution with 0.05 mol/L, the recoverable energy storage density of the NiO-PZO composite film is up to 19.6 J/cm3 under the electric field of 1038 kV/cm, which is 30% higher than that of the pure PZO film under the same conditions. Also, the energy storage efficiency of the composite film reaches 48%. Accordingly, we demonstrate a simple and convenient method by adding NiO to fabricate thin films with high energy storage performance.

Microstructure and Mechanical Properties of CoCrFeMnNiSnx High‑Entropy Alloys

X. Y. Gu,Y. N. Dong,Y. X. Zhuang,J. Wang 대한금속·재료학회 2020 METALS AND MATERIALS International Vol.26 No.3

The objective of this study is to investigate the effect of Sn content on the microstructure and mechanical properties of theCoCrFeMnNiSnxhigh entropy alloys. The microstructure and mechanical properties of the alloys have been studied by X-raydiffraction, scanning electron microscopy, room-temperature compressive tests and Vickers hardness tests. It has been foundthat Sn has a great effect on the microstructure and mechanical properties of the alloys. The CoCrFeMnNi alloy has a simpleFCC phase structure, while a few white precipitations (MnNi2Sn-like) are observed in the Sn0.03and Sn0.07alloys. With furtheradditions of Sn, the microstructure of Sn0.1,Sn0.3and Sn0.5changes to a typical dendrite structure, the dominated dendriteregion has a lattice of FCC structure which is enriched with Cr, Co and Fe, and the interdendritic region is enriched withMn, Ni and Sn. The volume of the MnNi2Sn-like phase increases with Sn content increasing. The addition of Sn enhancesthe formation of the MnNi2Sn-like phase in the CoCrFeMnNiSnxalloys, and improves the hardness and strength of as-castalloys, but reduces the ductility of the alloys. The strengthening mechanism of alloys was solid solution strengthening andformation of the MnNi2Sn-like phase. In the CoCrFeMnNiSn0.03and CoCrFeMnNiSn0.07alloys, the solid solution is thedominant mechanism. With the Sn content increasing, the second phase strengthening is the dominant mechanism.

Stimulated Release of Size‐Selected Cargos in Succession from Mesoporous Silica Nanoparticles

Wang, Cheng,Li, Zongxi,Cao, Dennis,Zhao, Yan&#x2010,Li,Gaines, Justin W.,Bozdemir, O. Altan,Ambrogio, Michael W.,Frasconi, Marco,Botros, Youssry Y.,Zink, Jeffrey I.,Stoddart, J. Fraser WILEY‐VCH Verlag 2012 Angewandte Chemie Vol.124 No.22

<P><B>Zwei Fliegen mit einer Klappe</B>: Die kovalente Bindung von β‐Cyclodextrin (gelb; siehe Bild) an mesoporöse Siliciumdioxid‐Nanopartikel (MSNs) ergibt ein duales Freisetzungssystem, das mit unterschiedlich großen Wirkstoffen (blaue und rote Kugeln) beladen werden kann, die sich auf verschiedene Stimuli hin nacheinander freisetzen lassen. Die kleineren Moleküle werden durch Absenken des pH‐Wertes freigesetzt, die größeren nach Abspaltung der Cyclodextrine von der MSN‐Oberfläche.</P>

Tokamak plasma disruption precursor onset time study based on semi-supervised anomaly detection

X.K. Ai,W. Zheng,M. Zhang,D.L. Chen,C.S. Shen,B.H. Guo,B.J. Xiao,Y. Zhong,N.C. Wang,Z.J. Yang,Z.P. Chen,Z.Y. Chen,Y.H. Ding,Y. Pan Korean Nuclear Society 2024 Nuclear Engineering and Technology Vol.56 No.4

Plasma disruption in tokamak experiments is a challenging issue that causes damage to the device. Reliable prediction methods are needed, but the lack of full understanding of plasma disruption limits the effectiveness of physics-driven methods. Data-driven methods based on supervised learning are commonly used, and they rely on labelled training data. However, manual labelling of disruption precursors is a time-consuming and challenging task, as some precursors are difficult to accurately identify. The mainstream labelling methods assume that the precursor onset occurs at a fixed time before disruption, which leads to mislabeled samples and suboptimal prediction performance. In this paper, we present disruption prediction methods based on anomaly detection to address these issues, demonstrating good prediction performance on J-TEXT and EAST. By evaluating precursor onset times using different anomaly detection algorithms, it is found that labelling methods can be improved since the onset times of different shots are not necessarily the same. The study optimizes precursor labelling using the onset times inferred by the anomaly detection predictor and test the optimized labels on supervised learning disruption predictors. The results on J-TEXT and EAST show that the models trained on the optimized labels outperform those trained on fixed onset time labels.

Influences of the Irradiation of Intense Pulsed Ion Beam (IPIB) on the Surface of Ni₃Al Base Alloy IC6

X. Y. Le,S. Yan,W. J. Zhao,B. H. Han,Y. G. Wang,J. M. Xue,H. T. Zhang 한국진공학회(ASCT) 2002 Journal of Korean Vacuum Science & Technology Vol.6 No.2

In this paper, we treated the Ni₃Al based alloy samples with intense pulsed ion beams (IPIB) at the beam parameters of 250KV acceleration voltage, 100 - 200 A/㎤ current density and 60 ㎱ pulse duration. We simulated the thermal-mechanical process near the surface of Ni₃Al based alloy with our STEIPIB codes. The surface morphology and the cross-section microstructures of samples were observed with SEM, the composition of the sample surface layer was determined by X-ray Energy Dispersive Spectrometry (XEDS) and the microstructure on the surface was observed by Transmission Electron Microscope (TEM). The results show that heating rate increases with the current density of IPIB and cooling rate reached highest value less than 150 A/㎤. The irradiation of IPIB induced the segregation of Mo and adequate beam parameter can improve anti-oxidation property of IC6 alloy. Some craters come from extraneous debris and liquid droplets, and some maybe due to the melting of the intersection region of interphase. Increasing the pulse number enlarges average size of craters and decreases number density of craters.