Promoting role of sulfur groups in selective catalytic reduction of NO with NH3 over H2SO4 modified activated carbons

Qianqian Guo,Wen Jing,Shangzeng Cheng,Zhanggen Huang,Dekui Sun,Yaqin Hou,Xiaojin Han 한국화학공학회 2015 Korean Journal of Chemical Engineering Vol.32 No.11

To determine the role of sulfur groups formed on activated carbon (AC) in the selective catalytic reduction (SCR) of NO with NH3, coal-based AC was modified by H2SO4 under various conditions and then treated in N2 atmosphere at 400 oC. The resulting carbons were characterized by N2 adsorption, elemental analysis, temperature programmed desorption and X-ray photoelectron spectroscopy, and tested for the SCR of NO with NH3 in the temperature range of 30-250 oC. Results reveal that H2SO4 modification has little effect on the textural properties, but promotes the formation of sulfur and oxygen groups. The sulfur groups incorporated by H2SO4 modification are mainly sulfonic groups and then sulfates. In particular, these sulfur groups play a predominant role in improving NH3 adsorption and then enhancing the SCR activity of modified carbons above 150 oC. However, the contribution of oxygen groups to NO reduction is very limited under the conditions employed in this work.

Substrate-Immersed Solvothermal Synthesis of Ordered SiO2/Ag Arrays as Catalytic SERS Substrates

Chang Liu,Qianqian Su,Li Li,Jie Sun,Jian Dong,Weiping Qian 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2018 NANO Vol.13 No.5

In this work, we designed a simple substrate-immersed solvothermal route for the one-step synthesis of novel ordered SiO2/Ag arrays, employing SiO2 colloidal crystals as templates and alcohol as reducing agent. The Ag nanoparticles were uniformly deposited in situ onto SiO2 colloidal crystals, which exhibited high surface enhanced Raman spectroscopy (SERS) activity and uniform SERS intensity. It was found that ordered SiO2/Ag arrays could rapidly scavenge the absorbed-Nile blue A (NBA) molecules from the surfaces with the assistance of H2O2, while the SERS signals of NBA decreased sharply and almost completely disappeared within four minutes. This can be attributed to the superior catalytic activity of Ag nanoparticles. After five times of re-immersion and re-absorbing process of NBA, the substrates could still keep ~74.8% SERS intensity versus the original. The high activity and durability of the as-prepared SiO2/Ag SERS substrate endow them as a promising candidate for trace detection.

The differentiation of cellular structure during encystment in the soil hypotrichous ciliate Australocirrus cf. australis (Protista, Ciliophora)

Qili Li,Xinpeng Fan,Qianqian Sun,Na Wu,Bing Ni,Fukang Gu 한국통합생물학회 2017 Animal cells and systems Vol.21 No.1

Ciliates are able to form resting cysts as a survival strategy in response to stressful environmental factors. Studies on the characteristics of cellular structure during encystment may provide useful information for further understanding of the regulatory mechanism of cellular patterns and supply new clues regarding the phylogeny of ciliates. Scanning and transmission electron microscopies were used to observe the ultrastructure of cells during encystment of the soil ciliate Australocirrus cf. australis. The dedifferentiation of ciliature was revealed for the first time. Ciliary shafts first shortened, and the remaining ciliature, including basal bodies and the fibrillar cirral basket, retracted into the cytoplasm and was surrounded by the autophagic vacuoles and then gradually digested. A large number of autophagic vacuoles were observed in mature resting cysts. Autophagy might not only be necessary for the differentiation of cellular structures during encystment but might also be important to sustain the basic life activities in the resting stage. Australocirrus cf. australis formed a kinetosome-resorbing cyst and contained four layers in the cyst wall: the ectocyst, mesocyst, endocyst and granular layer. The ciliature resorbing state and the number of layers in the cyst wall were consistent with those found in other oxytrichous ciliates. However, the phenomenon wherein the two macronuclear nodules are not fused during encystment is not commonly observed among oxytrichids. Additionally, the octahedral granules in the mesocyst of this species exhibit different morphology from the congeners.

Efficient End-to-End Failure Probing Matrix Construction in Data Center Networks

Jia, Zequn,Liu, Qiang,He, Ying,Wu, Qianqian,Liu, Ren Ping,Sun, Yantao 한국통신학회 2023 Journal of communications and networks Vol.25 No.4

Data centers play an essential role in the functioningof modern society. However, failures are unavoidable in datacenter networks (DCN) and will lead to negative impact on allapplications. Therefore, researchers are interested in the rapiddetection and localization of failures in DCNs. In this paper, we present a theoretical model to analyze theend-to-end failure detection methods in data center networks. Our numerical results verify that the proposed theoretical modelis accurate. In addition, we propose an algorithm to constructprobing matrices based on an enhanced probing path selectionindicator. We also introduce deep reinforcement learning (DRL)method to solve the problem and propose a DRL-based probingmatrix construction algorithm. Our experimental results showthat both of the proposed algorithms for constructing probingmatrices achieve better performance in detection accuracy thanexisting methods. We discussed different scenarios that thealgorithms are applicable to that can improve detection accuracyor construction speed performance.

Distinct Dose-Dependent Association of Free Fatty Acids with Diabetes Development in Nonalcoholic Fatty Liver Disease Patients

Fuxi Li,Junzhao Ye,Yanhong Sun,Yansong Lin,Tingfeng Wu,Congxiang Shao,Qianqian Ma,Xianhua Liao,Shiting Feng,Bihui Zhong 대한당뇨병학회 2021 Diabetes and Metabolism Journal Vol.45 No.3

Background: Excessive delivery of free fatty acids (FFAs) to the liver promotes steatosis and insulin resistance (IR), with IR defined as reduced glucose uptake, glycogen synthesis and anti-lipolysis stimulated by normal insulin levels. Whether the associations between FFAs and diabetes development differ between patients with and without nonalcoholic fatty liver disease (NAFLD) remains unclear. Methods: Consecutive subjects (2,220 NAFLD subjects and 1,790 non-NAFLD subjects according to ultrasound imaging) were enrolled from the First Affiliated Hospital of Sun Yat-sen University between 2009 and 2019. The homeostasis model assessment of insulin resistance (HOMA-IR) was calculated. Results: There was an approximate J-shaped relationship between FFA levels and HOMA-IR in the NAFLD group. Higher FFA concentration quartiles were associated with higher risks of IR (odds ratio [OR], 9.24; 95% confidence interval [CI], 6.43 to 13.36), prediabetes (OR, 10.48; 95% CI, 5.66 to 19.39), and type 2 diabetes mellitus (T2DM; OR, 19.43; 95% CI, 12.75 to 29.81) in the NAFLD group but not in the non-NAFLD group. The cut-off points for the FFA levels increased in a stepwise manner in discriminating IR, prediabetes and T2DM (573, 697, and 715 μmol/L) in the NAFLD group but not in non-NAFLD individuals. Conclusion: A distinct dose-dependent relationship of FFA levels was found with IR, prediabetes and T2DM in NAFLD patients. Screening serum FFA levels in NAFLD patients would be valuable in preventing diabetes development.

Enhancing the adsorption function of F⁻ by iron and zirconium doped zeolite: Characterization and parameter optimization

Bo Yang,Chaomin Jia,Guirong Sun,Bingxu Quan,Chunhui Zhang,Qianqian Huo,Peidong Su 대한환경공학회 2023 Environmental Engineering Research Vol.28 No.2

This study presented an original study on the F⁻ removal by Fe and Zr doped Gismondine-dominated Zeolite. Various modified zeolites are prepared by systematically adjusting the synthesis variables, namely pH, mass ratio of zeolite to modify agent (m<SUB>Zeolite:m(Fe+Zr)</SUB>), mass ratio of Fe to Zr (Fe:Zr) to investigate their effects on the F⁻ adsorption. The performance of prepared Fe-Zr-Zeolite on F⁻ removal was examined through both statistic adsorption and dynamic adsorption. Results indicated that when the modified pH was 7, the Fe:Zr ratio was 1:1 and m<SUB>Zeolite:m(Fe+Zr)</SUB> was 1:2, the modified natural zeolites which was named Fe-Zr-Zeolite showed the best removal efficiency on F⁻. Fe-Zr-Zeolite could remove over 80% when the initial concentration was less than 20 mg/L and F⁻ adsorption followed pseudo-second-order adsorption kinetic and Langmuir adsorption isotherm, indicating that F⁻ adsorption by Fe-Zr-Zeolite was chemically dominated. Besides, Fe-Zr-Zeolite had better removal efficiency of F⁻ under acidic conditions than that under alkaline conditions, and the competing anions, typically, Cl-, NO₃⁻ and SO₄<SUP>2-</SUP> had negligible effect on F⁻ removal by Fe-Zr-Zeolite. The dynamic adsorption test demonstrated that in order to maintain the high removal efficiency of F⁻, the filling thickness of Fe-Zr-Zeolite should be at least 30 ㎝ and the small the flow rate is, the higher the F⁻ removal efficiency will be.