Preparation of layered B4C with high neutron-shielding properties using graphene as template

Li Yang, Li Sanxi,Wang Song,Tian Chengcheng 한양대학교 청정에너지연구소 2023 Journal of Ceramic Processing Research Vol.24 No.1

In this paper, layered boron carbide (B4C) particles were successfully synthesized by sol-gel-low temperature pyrolysis methodusing boron acid and glycerin as raw materials with self-made reduced graphene oxide (RGO) as additives. The structure ofthe sol-gel condensation product was analyzed by FT-IR. The phase, morphology and particle size of the B4C werecharacterized by XRD, FE-SEM and LPSA. The results showed that boron carbide was rhombic crystal phase, but the surfaceof the particles was wrinkled and more layered. The B4C powders with uniform morphology and some particle sizes less than100 nm were prepared with the RGO content of 0.6%. Testing the neutron-shielding properties of the polypropylene-B4Ccomposites suggested that neutron transmittance with the B4C content of 35 wt% was 94.1% lower (from 70.6% to 4.1%) thanneat polypropylene, and the total macroscopic absorption cross-section was about 18 times larger (from 0.0857 ± 0.0031 cm-1 to1.5521 ± 0.0008 cm-1). The relative density, fracture toughness and hardness of self-made B4C ceramics (sB4C) were higherthan the commercially available B4C ceramics (cB4C). This study provided a new method for the preparation of B4C powderswith excellent neutron absorption properties and good sintering activity.

Increasing the Productivity of TNFR-Fc in GS-CHO Cells at Reduced Culture Temperatures

Tian-Ci Kou,Li Fan,Yan Zhou,Zhao-Yang Ye,Liang Zhao,Wen-Song Tan 한국생물공학회 2011 Biotechnology and Bioprocess Engineering Vol.16 No.1

In an effort to improve TNFR-Fc production in GS-CHO cells, batch cultures were performed to investigate the effects of low culture temperature on TNFR-Fc production. It was observed that low culture temperatures resulted in cell cycle arrest in the G1 phase, led to suppressed cell growth, and prolonged the culture period. Although the highest TNFR-Fc concentration was achieved with a culture temperature of 32°C at 247.4 mg/L, the maximum q_(TNFR-Fc) of 15.7 pg/cells/day was achieved at 30°C. Because the inhibition effect on cell growth at 30°C compromised its beneficial effects specifically to TNFR-Fc productivity, TNFR-Fc concentration at this temperature was not significantly increased. Furthermore, the increase in productivity of specific TNFR-Fc at low culture temperatures was also found to be due to an increase in the transcriptional level of the TNFR-Fc gene, determined by RT-PCR analysis. In addition, low culture temperatures had no significant effect on the degree of sialylation of TNFRFc. Taken together; a biphasic cultivation process developed in a fed-batch mode with a low temperature-production phase enhanced TNFR-Fc production by GS-CHO cells and therefore offers major potential for bioprocess optimization.

Retrospective Evaluation of Discrepancies between Radiological and Pathological Size of Hepatocellular Carcinoma Masses

Tian, Fei,Wu, Jian-Xiong,Rong, Wei-Qi,Wang, Li-Ming,Wu, Fan,Yu, Wei-Bo,An, Song-Lin,Liu, Fa-Qiang,Feng, Li,Liu, Yun-He Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.21

Background: The size of a hepatic neoplasm is critical for staging, prognosis and selection of appropriate treatment. Our study aimed to compare the radiological size of solid hepatocellular carcinoma (HCC) masses on magnetic resonance imaging (MRI) with the pathological size in a Chinese population, and to elucidate discrepancies. Materials and Methods: A total of 178 consecutive patients diagnosed with HCC who underwent curative hepatic resection after enhanced MRI between July 2010 and October 2013 were retrospectively identified and analyzed. Pathological data of the whole removed tumors wereassessed and differences between radiological and pathological tumor size were identified. All patients were restaged using a modified Tumor-Node-Metastasis (TNM) staging system postoperatively according to the maximum diameter alteration. The lesions were classified as hypo-staged, iso-staged or hyper-staged for qualitative assessment. In the quantitative analysis, the relative pre and postoperative tumor size contrast ratio ($%{\Delta}size$) was also computed according to size intervals. In addition, the relationship between radiological and pathological tumor diameter variation and histologic grade was analyzed. Results: Pathological examination showed 85 (47.8%) patients were overestimated, 82 (46.1%) patients underestimated, while accurate measurement by MRI was found in 11 (6.2%) patients. Among the total subjects, 14 (7.9%) patients were hypo-staged and 15 (8.4%) were hyper-staged post-operatively. Accuracy of MRI for calculation and characterized staging was related to the lesion size, ranging from 83.1% to 87.4% (<2cm to ${\geq}5cm$, p=0.328) and from 62.5% to 89.1% (cT1 to cT4, p=0.006), respectively. Overall, MRI misjudged pathological size by 6.0 mm (p=0.588 ), and the greatest difference was observed in tumors <2cm (3.6 mm, $%{\Delta}size=16.9%$, p=0.028). No statistically significant difference was observed for moderately differentiated HCC (5.5mm, p=0.781). However, for well differentiated and poorly differentiated cases, radiographic tumor maximum diameter was significantly larger than the pathological maximum diameter by 3.15 mm and underestimated by 4.51 mm, respectively (p=0.034 and 0.020). Conclusions: A preoperative HCC tumor size measurement using MRI can provide relatively acceptable accuracy but may give rise to discrepancy in tumors in a certain size range or histologic grade. In pathological well differentiated subjects, the pathological tumor size was significantly overestimated, but underestimated in poorly differentiated HCC. The difference between radiological and pathological tumor size was greatest for tumors <2 cm. For some HCC patients, the size difference may have implications for the decision of resection, transplantation, ablation, or arterially directed therapy, and should be considered in staging or selecting the appropriate treatment tactics.

Effect of ethylene glycol on the synthesis of crystalline boron carbide powder from condensed boric-acid-glycerin precursor

Li Yang,Li Sanxi,Wang Song,Tian Chengcheng,Otitoju Tunmise Ayode 한양대학교 청정에너지연구소 2023 Journal of Ceramic Processing Research Vol.24 No.2

The effect of addition of ethylene glycol (C2H6O2) on the synthesis of crystalline boron carbide (B4C) powder from a condensedboric acid (H3BO3)-glycerin (C3H8O3) product was investigated. Equal molar amount of H3BO3 and glycerin was mixed andsubjected to dehydration-condensation reaction using various amount of ethylene glycol (0 to 40 mol% based on glycerolamount). Then the condensed product was thermally decomposed in air twice to obtain surface carbon-free precursor powder. The crystalline phases and surface functional groups of the material was characterized using XRD, SEM, FTIR and TGA. Addition of ethylene glycol offered a new organic sites and comparatively, reduced pyrolysis temperature from 700 to 650 oC. The complete formation of crystalline B4C powder was achieved at 1475 oC within 2.5 h, which is among the shortest timereported for B4C synthesis

Asymmetric selenophene-based non-fullerene acceptors for high-performance organic solar cells

Li, Chao,Xia, Tian,Song, Jiali,Fu, Huiting,Ryu, Hwa Sook,Weng, Kangkang,Ye, Linglong,Woo, Han Young,Sun, Yanming The Royal Society of Chemistry 2019 Journal of materials chemistry. A, Materials for e Vol.7 No.4

<P>Compared to thiophene-based non-fullerene acceptors (NFAs), selenophene-based NFAs have received much less attention. And organic solar cells (OSCs) based on selenophene-containing NFAs typically exhibit relatively low power conversion efficiency (PCE < 12%) and fill factor (FF < 70%). In this contribution, we have designed and synthesized two asymmetric selenophene-based NFAs, named SePTT-2F and SePTTT-2F, which possess the same end-capping group but different selenophene-containing conjugated backbones. On comparing the two NFAs, SePTTT-2F with more extended conjugation in the backbone was found to have almost the same maximum absorption peak and optical bandgap in film as SePTT-2F but an up-shifted lowest unoccupied molecular orbital (LUMO) energy level and higher electron mobility. By pairing the NFAs with the polymer donor PBT1-C, the resultant blend film based on SePTTT-2F exhibited higher and more balanced charge mobilities and more efficient exciton dissociation and charge collection in comparison with the SePTT-2F-based blend film. As a result, OSCs based on SePTTT-2F delivered an impressively high PCE of 12.24% with an outstanding FF of 75.9%, much higher than those of the SePTT-2F-based OSCs. To the best of our knowledge, the PCE of 12.24% and FF of 75.9% are among the highest values reported in the literature so far for both the parameters amongst selenophene-containing NFA-based OSCs. Our results demonstrate that extending the conjugation in the selenophene-containing backbone is an effective strategy to design highly efficient selenophene-based NFAs.</P>

Numerical simulations of a horizontal axis water turbine designed for underwater mooring platforms

Tian, Wenlong,Song, Baowei,VanZwieten, James H.,Pyakurel, Parakram,Li, Yanjun The Society of Naval Architects of Korea 2016 International Journal of Naval Architecture and Oc Vol.8 No.1

In order to extend the operational life of Underwater Moored Platforms (UMPs), a horizontal axis water turbine is designed to supply energy for the UMPs. The turbine, equipped with controllable blades, can be opened to generate power and charge the UMPs in moored state. Three-dimensional Computational Fluid Dynamics (CFD) simulations are performed to study the characteristics of power, thrust and the wake of the turbine. Particularly, the effect of the installation position of the turbine is considered. Simulations are based on the Reynolds Averaged Navier-Stokes (RANS) equations and the shear stress transport ${\kappa}-{\omega}$ turbulent model is utilized. The numerical method is validated using existing experimental data. The simulation results show that this turbine has a maximum power coefficient of 0.327 when the turbine is installed near the tail of the UMP. The flow structure near the blade and in the wake are also discussed.

Computation of pressure fluctuation frequency in electronic unit pump for diesel engine

Tian Bing-qi,Fan Li-yun,Qaisar Hayat,Ma Xiuzhen,Song En-zhe,Hao Wang 대한기계학회 2014 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.28 No.4

Pressure variations inside a fuel injection system can lead to fluctuations in injected fuel quantity during injections and therefore candirectly impact the stability and performance coherence of the fuel injection system and the engine it matched. Concepts of hydrauliccapacitance and hydraulic inductance are introduced into fuel injection system by referencing LC oscillator electric circuit. A LC undampedhydraulic mathematical model is developed based on the structural parameters of the electronic unit pump (EUP). Pressure fluctuationfrequency during injection process at different operating conditions of the EUP is computed by the LC undamped model. It isobserved that the frequencies of pressure fluctuations tend to increase with the fuel injection process. Pressure curves and pressure fluctuationfrequencies obtained by experiments at different operating conditions validated the results predicted by the LC undampedmathematical model.

Calixarene-based chemosensors by means of click chemistry.

Song, Miaomiao,Sun, Zhongyue,Han, Cuiping,Tian, Demei,Li, Haibing,Kim, Jong Seung Wiley-VCH 2014 Chemistry - An Asian Journal Vol.9 No.9

<P>Click chemistry, a new strategy for organic chemistry, has been widely used in the chemical modification of calixarenes because of its reliability, specificity, biocompatibility, and efficiency. Click-derived triazoles also play a critical role in sensing ions and molecules. This in-depth review provides an overview of calixarene-based chemosensors that incorporate click-derived triazoles, and their three characteristics (chromogenic, fluorescence, and wettability) are reviewed.</P>

Effect of Different Tumbling Marination Treatments on the Quality Characteristics of Prepared Pork Chops

Tian Gao,Jiaolong Li,Lin Zhang,Yun Jiang,Ruixue Ma,Lei Song,Feng Gao,Guanghong Zhou 아세아·태평양축산학회 2015 Animal Bioscience Vol.28 No.2

The effect of different tumbling marination treatments (control group, CG; conventional static marination, SM; vacuum continuous tumbling marination, CT; vacuum intermittent tumbling marination, IT) on the quality characteristics of prepared pork chops was investigated under simulated commercial conditions. The CT treatment increased (p<0.05) the pH value, b* value, product yield, tenderness, overall flavor, sensory juiciness and overall acceptability in comparison to other treatments for prepared boneless pork chops. The CT treatment decreased (p<0.05) cooking loss, shear force value, hardness, gumminess and chewiness compared with other treatments. In addition, CT treatment effectively improved springiness and sensory color more than other treatments. However, IT treatment achieved the numerically highest (p<0.05) L* and a* values. These results suggested that CT treatment obtained the best quality characteristics of prepared pork chops and should be adopted as the optimal commercial processing method for this prepared boneless pork chops.

Origin of Improved Photoelectrochemical Water Splitting in Mixed Perovskite Oxides

Li, Weiwei,Jiang, Kai,Li, Zhongguo,Gong, Shijing,Hoye, Robert L. Z.,Hu, Zhigao,Song, Yinglin,Tian, Chuanmu,Kim, Jongkyoung,Zhang, Kelvin H. L.,Cho, Seungho,MacManus-Driscoll, Judith L. Wiley (John WileySons) 2018 ADVANCED ENERGY MATERIALS Vol.8 No.31