Potassium isotope fractionation between K-salts and saturated aqueous solutions at room temperature: Laboratory experiments and theoretical calculations

Li, Weiqiang,Kwon, Kideok D.,Li, Shilei,Beard, Brian L. Pergamon Press 2017 Geochimica et cosmochimica acta Vol.214 No.-

<P><B>Abstract</B></P> <P>Improvements in mass spectrometry have made it possible to identify naturally occurring K isotope (<SUP>39</SUP>K/<SUP>41</SUP>K) variability in terrestrial samples that can be used in a variety of geological and biological applications that involve cycling of K such as clay or evaporite formation. However, our ability to interpret K isotope variability is limited by a poor understanding of how K isotopes are fractionated at low temperatures. In this study, we conducted recrystallization experiments of eight K-salts in order to measure the K isotope fractionation factor between the salt and the saturated K solution (Δ<SUP>41</SUP>K<SUB>min-sol</SUB>). Measured Δ<SUP>41</SUP>K<SUB>min-sol</SUB> are +0.50‰ for K<SUB>2</SUB>CO<SUB>3</SUB>·1.5H<SUB>2</SUB>O, +0.32‰ for K<SUB>2</SUB>SO<SUB>4</SUB>, +0.23‰ for KHCO<SUB>3</SUB>, +0.06‰ for K<SUB>2</SUB>C<SUB>2</SUB>O<SUB>4</SUB>·H<SUB>2</SUB>O, +0.02‰ for KCl, −0.03‰ for K<SUB>2</SUB>CrO<SUB>4</SUB>, −0.15‰ for KBr, and −0.52‰ for KI. Overall the Δ<SUP>41</SUP>K<SUB>min-sol</SUB> decreases with increasing <I>r</I> for K in crystals, where <I>r</I> is the average distance between a K atom and its neighboring atoms of negative charge. Salts with monovalent anions and salts with divalent anion complexes define different linear trends with distinct slopes on a plot of Δ<SUP>41</SUP>K<SUB>min-sol</SUB> - <I>r</I>. We applied <I>ab initio</I> lattice dynamics and empirical crystal-chemistry models to calculation of K isotope fractionation factors between K salts; both methods showed that the calculated inter-mineral K isotope fractionation factors (Δ<SUP>41</SUP>K<SUB>min-KCl</SUB>) are highly consistent with experimentally derived Δ<SUP>41</SUP>K<SUB>min-KCl</SUB> under the assumption of consistent β factors for different saturated K solutions. Formulations for the crystal-chemistry model further indicate that both anion charge and bond length <I>r</I> are the principle controlling factors for K isotope fractionation, and the K isotope fractionation factors correlate with <I>r</I> following a 1/<I>r</I> <SUP>3</SUP> relationship. Our experiment and theoretical study confirms the existence of significant equilibrium K isotope fractionation at ambient conditions, and the K isotope fractionation factors for halides and sulfate obtained in this study provide a basis for future K isotope studies on evaporites.</P>

Numerical simulation of methanol steam reforming based on Cu/ZnO/Al2O3 via micro-channel reactor for hydrogen production

Weiqiang Kong,Qiuwan Shen,Jiadong Liao,Ziheng Jiang,Naibao Huang,Guogang Yang,Shian Li 한양대학교 청정에너지연구소 2024 Journal of Ceramic Processing Research Vol.25 No.2

A three-dimensional numerical model of a methanol steam reforming micro-channel reactor for hydrogen production based onCu/ZnO/Al2O3 catalyst was established. The effects of different inlet mass flow rate, reaction temperature and steam to carbonratio (S/C) on the mass change of each component, chemical reaction rate and hydrogen production performance of microchannelreformer were studied. The results show that with the increase of inlet mass flow rate, the mass fraction of CH3OH atthe outlet of reforming channel increases gradually, and the methanol conversion rate decreases gradually. The mass fractionof CO at the outlet of reforming channel decreases gradually, and the CO selectivity decreases gradually. With the increase ofreaction temperature, the mass fraction of CH3OH at the outlet of reforming channel decreases gradually, and the methanolconversion rate increases. The mass fraction of CO at the outlet of reforming channel increases rapidly, and the CO selectivityincreases rapidly. With the increase of S/C, the methanol conversion rate increased and the CO selectivity decreased. In thisstudy, the influence of reaction conditions on methanol reformer was obtained, and the reasons behind it were clarified, whichprovided more valuable insights for the operating conditions of hydrogen production from MSR.

Construction of an Efficient Mutant Strain of Trichosporonoides oedocephalis with HOG1 Gene Deletion for Production of Erythritol

( Liangzhi Li ),( Tianyi Yang ),( Weiqiang Guo ),( Xin Ju ),( Cuiying Hu ),( Bingyu Tang ),( Jiaolong Fu ),( Jingsheng Gu ),( Haiyang Zhang ) 한국미생물 · 생명공학회 2016 Journal of microbiology and biotechnology Vol.26 No.4

The mitogen-activated protein kinase HOG1 (high-osmolarity glycerol response pathway) plays a crucial role in the response of yeast to hyperosmotic shock. Trichosporonoides oedocephalis produces large amounts of polyols (e.g., erythritol and glycerol) in a culture medium. However, the effects of HOG1 gene knockout and environmental stress on the production of these polyols have not yet been studied. In this study, a To-HOG1 null mutation was constructed in T. oedocephalis using the loxP-Kan-loxP/Cre system as replacement of the targeted genes, and the resultant mutants showed much smaller colonies than the wild-type controls. Interestingly, compared with the wild-type strains, the results of shake-flask culture showed that To-HOG1 null mutation increased erythritol production by 1.44-fold while decreasing glycerol production by 71.23%. In addition, this study investigated the effects of citric acid stress on the T. oedocephalis HOG1 null mutants and the wild-type strain. When the supplementation of citric acid in the fermentation medium was controlled at 0.3% (w/v), the concentration of erythritol produced from the wild-type and To-HOG1 knockout mutant strains improved by 18.21% and 21.65%, respectively.

Impact response of ultra-high performance fiber-reinforced concrete filled square double-skin steel tubular columns

Jie Li,Weiqiang Wang,Chengqing Wu,Zhongxian Liu,Pengtao Wu 국제구조공학회 2022 Steel and Composite Structures, An International J Vol.42 No.3

This paper studies the lateral impact behavior of ultra-high performance fiber-reinforced concrete (UHPFRC) filled double-skin steel tubular (UHPFRCFDST) columns. The impact force, midspan deflection, and strain histories were recorded. Based on the test results, the influences of drop height, axial load, concrete type, and steel tube wall thickness on the impact resistance of UHPFRCFDST members were analyzed. LS-DYNA software was used to establish a finite element (FE) model of UHPFRC filled steel tubular members. The failure modes and histories of impact force and midspan deflection of specimens were obtained. The simulation results were compared to the test results, which demonstrated the accuracy of the finite element analysis (FEA) model. Finally, the effects of the steel tube thickness, impact energy, type of concrete and impact indenter shape, and void ratio on the lateral impact performances of the UHPFRCFDST columns were analyzed.

Extraction of chitin from white shrimp (Penaeus vannamei) shells using binary ionic liquid mixtures

Qiqi Dong,Weiqiang Qiu,Li Li,Ningping Tao,Ashley Liang Wang,Shanggui Deng,Yinzhe Jin 한국공업화학회 2023 Journal of Industrial and Engineering Chemistry Vol.120 No.-

Binary ionic liquid mixtures (IL) were used for the first time to extract chitin from shrimp shells. Twoionic liquids, 1-ethyl-3-methylimidazole acetate ([EMIM][Ac]) and 1-butyl-3-methylimidazole bromidesalt ([BMIM][Br]), were mixed at ratios of 0:1, 1:1, 3:2, 4:1, and 1:0 and the properties of the IL andthe characteristics of extracted chitin were investigated. With an increase in proportion of [EMIM][Ac],the viscosity, dielectric constant, and dielectric loss of IL gradually decreased (p < 0.05), whereas the conductivity,radius of gyration increased (p < 0.05). The best quality of chitin using IL (3:2) was achievedwhen the viscosity, conductivity, and radius of gyration were 0.16 ± 0.00 Pa s, 0.30 ± 0.01 S/m, and 0.10 ± 0.00 nm, respectively. The yield of chitin extraction using IL was 35.72 ± 0.31 %, and this was approximately2.04 times higher than that using the acid-base method (17.50 ± 0.16 %). The Whiteness index(WI) of chitin extracted using IL (3:2) (94.93 ± 0.09) was better than commercial chitin (93.31 ± 0.11),and the secondary structure, surface morphology and thermal stability were similar to commercial chitin. Therefore, the binary ionic liquid mixture can be used as an effective green solvent to extract chitin fromshrimp shells.

Design and Analysis of the Directional Transport Device for Bulk Rod Materials in Sand Fixation Equipment

Zhuang Guo,Weiqiang Zheng,Liping Zhang,Fei Li 한국정밀공학회 2023 International Journal of Precision Engineering and Vol.24 No.1

To address the problem that sand fixation equipment cannot use bulk rod material for conveying operations, a directional transport device for bulk rod materials is designed, which realizes the flipping conveying of rod material from horizontal to vertical direction. The rod material is directionally conveyed under the clamping of two adjacent forks of the chain conveyor belt. The directional turning process of the rod material is analysed using the discrete element method, and the operating principle and feasibility of the rod material’s directional transportation are explained. To optimize the working performance of the device, an orthogonal combination test is carried out through physical prototype, with the conveying thickness, filling rate and conveyance speed of the rod material as the experimental factors, and the rod material’s qualified rate as the test index. The test results show that the experimental factors mentioned above can be ranked from the filling rate, the conveyance speed and then to the conveyance thickness according to their degrees of influence on the delivery rate of rod materials. The optimal parameter combination is obtained, and the results are also verified by experiments. This study has solved the problem of directional transport device for bulk rod materials in sand fixation equipment, which has theoretical significance and application value in the design of sand fixation equipment material conveying system.

Differential Subsampling with Cartesian Ordering Contrast-Enhanced Magnetic Resonance Angiography for the Preoperative Assessment of Anterolateral Thigh Flap

Shen Yunfeng,Li Xiucun,Zhang Chao,Zhong Hai,Dou Weiqiang 대한영상의학회 2022 Korean Journal of Radiology Vol.23 No.8

Objective: To investigate the clinical application of differential subsampling with Cartesian ordering (DISCO) contrastenhanced (CE) magnetic resonance angiography for anterolateral thigh (ALT) flap transplantation, using operative findings as a reference. Materials and Methods: Thirty patients (21 males and nine females; mean age ± standard deviation, 45.5 ± 15.6 years) who were scheduled to undergo reconstruction with ALT flaps between June 2020 and June 2021 were included in the prospective study. Before ALT flap transplantation, patients were scanned using CE-DISCO imaging. All acquired DISCO images of the 60 lower limbs (both sides from each patient) were analyzed using maximum intensity projection and volume rendering methods. Two experienced radiologists were employed to examine the patterns of the lateral circumflex femoral artery (LCFA), its branches, and perforators and their skin termini, which were compared with the operative findings. Results: Using CE-DISCO, the patterns of the LCFA and its branches were clearly identified in all patients. Four different origins of the LCFA were found among the 60 blood vessels: type I (44/60, 73.3%), type II (6/60, 10.0%), type III (8/60, 13.3%), and type IV (2/60, 3.3%). Owing to a lack of perforators entering the skin, two patients did not undergo ALT flap transplantation. For the remaining 28 patients, the ALT flaps in 26 patients were successfully operated without flap reselection during the operation, while the remaining two patients underwent other surgical procedures due to the thin diameter of the perforator or injury of the perforator during the operation. The success rate of flap transplantation was 92.8% (26/28). All transplanted flaps exhibited good blood supply and achieved primary healing without infection or delayed healing. Conclusion: CE-DISCO imaging can be an effective method for preoperative perforator imaging before ALT flap transplantation.

Toxoplasma gondii Induces Apoptosis via Endoplasmic Reticulum Stress-Derived Mitochondrial Pathway in Human Small Intestinal Epithelial Cell-Line

Hao Wang,Chunchao Li,Wei Ye,Zhaobin Pan,Jinhui Sun,Mingzhu Deng,Weiqiang Zhan,Jiaqi Chu 대한기생충학열대의학회 2021 The Korean Journal of Parasitology Vol.59 No.6

A Novel Jig Dyeing Apparatus for Dyeing Polyester with Supercritical Carbon Dioxide and its Dyeing Effect

Zhaotao Gao,Dehao Qu,Yanpeng Qu,Weiqiang Wang,Shurui Cui,Hongxiao Guo,Fei Li,Fayu Sun 한국섬유공학회 2022 Fibers and polymers Vol.23 No.3

In this work, a novel jig dyeing apparatus for dyeing polyester with supercritical carbon dioxide was designed andsuccessfully constructed. The built-in dye boxes set inside and guide roller to increase the exposure area of single layer fabricwere the two most attractive features of the equipment. Polyester was dyed at a temperature of 130 oC, the pressure of27 MPa. The colorfastness was analyzed as a function of polyester running speed. Under the condition that the polyester'srunning speed was 4 m/s, the fastness to staining, the fastness to fading, and the fastness to rubbing were rated at a grade of 3-4, 4-5, and 4, respectively. Dyeing properties complied with the expected requirements.

Recent trends in therapeutic application of engineered blood purification materials for kidney disease

Cui Gao,Qian Zhang,Yi Yang,Yangyang Li,Weiqiang Lin 한국생체재료학회 2022 생체재료학회지 Vol.26 No.1

Blood purification is a commonly used method to remove excess metabolic waste in the blood in renal replacement therapy. The sufficient removal of these toxins from blood can reduce complications and improve survival lifetime in dialysis patients. However, the current biological blood purification materials in clinical practice are not ideal, where there is an unmet need for producing novel materials that have better biocompatibility, reduced toxicity, and, in particular, more efficient toxin clearance rates and a lower cost of production. Given this, this review has carefully summarized newly developed engineered different structural biomedical materials for blood purification in terms of types and structure characteristics of blood purification materials, the production process, as well as interfacial chemical adsorption properties or mechanisms. This study may provide a valuable reference for fabricating a user-friendly purification device that is more suitable for clinical blood purification applications in dialysis patients.