Accelerated removal of nitrate from aqueous solution by utilizing polyacrylic anion exchange resin with magnetic separation performance

Haiou Song,Zhijian Yao,Chendong Shuang,Aimin Li 한국공업화학회 2014 Journal of Industrial and Engineering Chemistry Vol.20 No.5

In order to quickly remove nitrate from aqueous solution, a magnetic strong base quaternary ammonium anion exchange resin (MAER) has been successfully designed and synthesized. The physicochemical properties of the MAER as well as its adsorption ones for nitrate removal were investigated in detail. A series of batch experiments were carried out to evaluate the effects of several factors on removal efficiency of nitrate, such as retention time, resin amount and initial nitrate concentration. Compared to the commercial Purolite A300 and D213, the equilibrium time for the adsorption process using MAER was only around 20 min, which is significantly less than that of two ones mentioned. Furthermore, the kinetic process of nitrate sorption on MAER could be well described by both pseudo-first-order and pseudo-second-order models. In addition, the results of batch experiments can be better fitted by the Langmuir and Freundlich adsorption isotherm models. Most importantly, the effects of competing ions on nitrate removal followed the order as: SO42- > Cl- > HCO3- . These results are of significance in guiding the development of novel resins with the rapid nitrate removal rate from aqueous solution, which would improve efficiency and save energy greatly.

Updated SSDP Scheme for DDoS Attack Defense

( Haiou Huang ),( Liang Hu ),( Jianfeng Chu ) 한국인터넷정보학회 2018 KSII Transactions on Internet and Information Syst Vol.12 No.9

Abusing the Simple Server Discovery Protocol (SSDP) can induce an SSDP attack (including SSDP DoS, DDoS, DRDoS) posing a significant threat to UPnP devices. Rapid and extensive developments in computer technology, especially in regards to IoT, have made Upnp devices an indispensable part of our daily lives - but also render them susceptible to a variety of SSDP attacks without suitable countermeasures. This paper proposes the Two-dimensional table scheme, which provides high security at a reasonable computational cost. The feasibility and effectiveness of the proposed scheme are also validated by comparison against four other schemes (Stateless connections, Failing-together, Cookie, and Client puzzle).

한국과 중국의 노후소득보장제도의 비교연구 -한국의 국민연금제도와 중국의 양로보험제도를 중심으로-

HUANG HAIOU,이수진,허용훈 한국지방정부학회 2024 지방정부연구 Vol.27 No.4

The purpose of this study is to explore pension system reform proposals that can better cope with the aging society through comparative evaluation of the pension systems of the two countries. The most important problems of the Korea National Pension Service are as follows. The first is the long-term instability of the national pension system. According to the National Pension Service's Financial Estimation Committee(2018), the premium rate is expected to reach 30-40% if the national pension is operated under the pay-as-you-go system. Secondly, the national pension system, as Korea's core pension system, has a wide blind spot and is unable to properly respond to the reduction of poverty among the elderly. Third, it is pointed out that the national pension system is backward because, unlike the income tax system, all income groups pay the same insurance premiums at the same rate. Finally, the national pension has a strong redistribution function, but it is not suitable for Korea’s social and cultural environment, and its function is seriously distorted. In Korea, the income of self-employed people has not yet been accurately identified. Like Korea, China has made great efforts to reform the China’s old aged pension system so far. Looking specifically at the problems of China's old-age pension system, the first problem of the old-age pension system is that only 65% of the total population is covered by the old-age pension system. The second problem of old-age pension for urban and rural residents is that the old-age pension benefits level for urban and rural residents is "extremely" low. One reason for this is the low level of growth in individual accounts paid by the insured. The third problem is the financial problem. The biggest key is how to secure stable finances, and ensure the sustainability of pension system. Of course, this is not only a problem for China, but also for South Korea and other European countries. The fourth problem is delivery system in Old-age Pension System for urban and rural residents. The level of control over the old-age pension system is low, supervision is inadequate, and there is a discrepancy with reality.​ So far, the problems of Korea's national pension system and China's old-aged pension system have been compared and analyzed. As in Korea and China, fiscal sustainability must be further strengthened in order for the pension system to develop. To this end, it is desirable to accept the pension reform strategy recommended by the World Bank.

Solution‑Processed Individual Multiple‑Junction Structure Self‑Assembled with ZnO Nanowires for UV/Blue Detection

Yan Li,Naisen Yu,Haiou Li,Dedi Liu,Yunfeng Wu 대한금속·재료학회 2020 ELECTRONIC MATERIALS LETTERS Vol.16 No.6

In this paper, a novel individual multiple-junction network structure is fabricated using low temperature aqueous method. In comparison with the same growth method without NaF adding, the Fluorine doped ZnO photodetector presents multiplejunctionnetwork structure and ultraviolet (UV)/Blue dual band photoresponse performances. The results indicate the method can simultaneously promote self-assembled growth and improve the photoresponse properties. Moreover, it will provide a simple and low cost way to assemble multiple nanowires for photoresponse applications.

A facile approach to preparing palladium nanoparticles-embedded polyvinylpyrrolidone (PVP) heterogeneous hybrid nanofibers mats by electrospinning

Jie Bai,Liping Guo,Haiou Liang,Tong Xu,Chunping Li,Qingrun Meng,Huan Liu,Yarong Huang 한국화학공학회 2013 Korean Journal of Chemical Engineering Vol.30 No.12

Well-dispersed palladium nanoparticles (Pd NPs) were prepared under the condition that trisodium citrate was the reduction agent and polyvinylpyrrolidone (PVP) was the stabilizing agent via sol-gel process. By making good use of the advanced electrospinning technology we obtained Pd NPs/PVP composite nanofibers films. Optical properties were examined by UV-visible absorbance spectra (UV-vis) and Fourier transform infrared spectroscopy (FTIR). The morphology and distribution of Pd NPs in/on PVP matrix were characterized by scanning electron microscope (SEM)and transmission electron microscope (TEM). The results showed that Pd NPs presented as spherical spots and distributed in/on PVP nanofibers uniformly; their diameter was 4-10 nm and decreased with the increase of PVP. The as-prepared Pd NPs/PVP hybrid mats possess catalytic activity, stability and reusability, as verified by performance in Heck reaction.

A socioecological framework for research on work and obesity in diverse urban transit operators based on gender, race, and ethnicity

BongKyoo Choi,Peter Schnall,Marnie Dobson,Haiou Yang,Dean Baker,YoungJu Seo 대한직업환경의학회 2017 대한직업환경의학회지 Vol.29 No.-

Urban transit (bus and rail) operators, totaling nearly 700,000 persons, are one of the heaviest occupational groups in the United States (US). Little is known about occupational risk factors for weight gain and obesity and their interrelationship with health-related behaviors, particularly among female minority (African Americans and Hispanics) transit operators who are at greater risk for obesity. As a step towards developing successful obesity interventions among urban transit operators, this paper aims to present a new socioecological framework for studying working conditions, chronic strain, health-related behaviors, weight gain/obesity, and obesity disparity in diverse urban transit operators based on gender, race, and ethnicity. Our framework is a synthesis of several different theories and disciplines: the resource-work load model (work stress), occupational ergonomics, the theory of intersectionality, and worksite health promotion. The framework was developed utilizing an extensive literature review, results from our on-going research on obesity, input from focus groups conducted with Los Angeles transit operators as well as interviews and meetings with transit operator stakeholders (management, unions, and worksite transit wellness program), and ride-along observations. Our hypotheses highlighted in the framework (see Fig. 1) are that adverse working conditions, largely characterized as a combination of high demands and low resources, will increase the risk for weight gain/obesity among transit operators directly through chronic strain and hypothalamic dysfunction (hyper-and hypo-activations), and indirectly through health-related behaviors and injuries/chronic severe pain. We also hypothesize that the observed increase in adiposity among female minority operators is due to their greater exposure to adverse occupational and non-occupational conditions that reflect their intersecting social identities of lower social class and being a minority woman in the US. Our proposed framework could greatly facilitate future transit worksite obesity studies by clarifying the complex and important roles of adverse working conditions in the etiology of weight gain/obesity and obesity disparity among transit operators and other working populations.

Olaparib induced senescence under P16 or P53 dependent manner in ovarian cancer

Zehua Wang,Jianwen Gao,Jiabing Zhou,Haiou Liu,Congjian Xu 대한부인종양학회 2019 Journal of Gynecologic Oncology Vol.30 No.2

Objective: Poly (ADP-ribose) polymerase (PARP) is an important molecule in the early stress response of DNA damage, which is involved in DNA damage repair and cellular senescence. Olaparib, as PARP inhibitor, has an anti-tumor effect on high grade serous ovarian cancer, but its effects on cellular senescence have not been reported. This study intends to explore the role of olaparib in the regulation of senescence in ovarian cancer cells. Methods: The effects of olaparib on the senescence of ovarian cancer cells were detected by using the senescence-associated β-galactosidase (SA-β-Gal) and senescence-associated heterochromatin aggregation (SAHF). Quantitative real-time polymerase chain reaction was used to analyze the senescence-associated secretory phenotype (SASP). Cell cycle and apoptosis were detected by flow cytometry. The effect of olaparib on tumor growth was analyzed in a nude mouse xenograft transplantation model. Results: Long-term (6 days) treatment with olaparib (5 μM) significantly inhibited the growth of ovarian cancer cells, leading to arrest the cell cycle at G0/G1 phase, significant increase the number of positive SA-β-Gal stained cells and positive SAHF cells. The expression of P16 and retinoblastoma protein (p-RB) were significantly enhanced in SKOV3 cells under olaparib treated, meanwhile, the expression of P53 and p-RB were upregulated in A2780 cells. In OVCAR-3 cells, the expression of P53 was downregulated and p-RB was upregulated. Mice with SKOV3 xenograft transplantation was given olaparib (10 mg/kg/day) via abdominal cavity administration, the tumor volume was reduced (p<0.01). Conclusion: Continuous low dosage administration of olaparib induced senescence under P16 or P53 dependent manner in ovarian cancer.

Novel Organic/Inorganic Hybrid Star Polymer Surface-Crosslinked with Polyhedral Oligomeric Silsesquioxane

Jingyan Zhang,Dong Si,Shifeng Wang,Hao Liu,Xiaoming Chen,Haiou Zhou,Mingdi Yang,Guoying Zhang 한국고분자학회 2020 Macromolecular Research Vol.28 No.2

Novel organic/inorganic hybrid star polymer was prepared dually crosslinked within inner-core via divinylbenzene (DVB) and outer-surface via octafunctional polyhedral oligomeric silsesquioxane (POSS). Core cross-linked star polymers bearing dialkynyl-terminated polystyrene arms, (dialkynyl-PS)n-CCL, were synthesized at first by the atom transfer radical polymerization (ATRP) of DVB using α,α-dialkynyl-terminated PS macroinitiator, followed by the subsequent fractionation. Under high dilution conditions, (dialkynyl-PS)n-CCL was subjected to surface cross-linking with octa(3- azidopropyl) polyhedral oligomeric silsesquioxane, POSS-(N3)8, via click reaction, affording POSS-functionalized hybrid polymer doubly cross-linked within core and surface regions, SCL-(PS)n-CCL. FT-IR, 1H NMR, GPC, and elemental analysis results revealed that on average, the obtained hybrid polymer possesses a cross-linked PDVB inner core, ~14 linear PS arms (the MW per arm of 5.1 kDa), and ~4-5 POSS moieties at outer surface. Differential scanning calorimetry (DSC) thermograms and thermogravimetric analysis (TGA) revealed that after surface cross-linking the thermal stability of SCL-(PS)n-CCL is considerably improved. This work provides a proof-of-concept example for the preparation of dually cross-linked hybrid star polymer, which represents a novel category of organic/inorganic composite materials with unique chain architectures.

Development of Train Regenerative Braking Ground Absorbing Device Based on Super Capacitor Energy Storage

LI Kunpeng,LIU Wei,LI Qunzhan,ZHAO Yunyun,HE Zhixin,SHI Haiou,JIN Shoujie,CHEN Guangzan 전력전자학회 2019 ICPE(ISPE)논문집 Vol.2019 No.5

The rational use of regenerative braking energy for urban rail transit trains directly affects the voltage safety of the traction power supply system and the electric braking function of the train. It is also of great significance for the implementation of train traction energy saving. This paper proposes a scheme of train regenerative braking ground absorbing device based on super-capacitor energy storage. It adopts multiple modular Buck/Boost DC conversion topology to realize bidirectional control of electric energy and stabilize the secondary utilization of traction network voltage and regenerative electric energy. According to the scheme of this paper, the energy storage device was developed and verified in the engineering of the Guangzhou Line 6 main line traction substation. The test indicators have met the design expectations.

An In situ Forming Hydrogel Based on Photo-Induced Hydrogen Bonding

Jingyan Zhang,Shifeng Wang,Zeren Zhao,Dong Si,Haiou Zhou,Mingdi Yang,Xianbiao Wang 한국고분자학회 2020 Macromolecular Research Vol.28 No.12

Stimulus-induced in situ forming hydrogels possess the characteristics of easy management and minimal invasiveness via simple injection at target sites with a liquid and easy forming bulk gels. In the present study, a photoreactive monomer, N'-(2-nitrobenzyl)-N-acryloyl glycinamide (NBNAGA) was introduced to modify polyacrylamide (PAM) hydrogel preparation with stimuli responsiveness. Firstly, poly(acrylamide-co-N'-(2-nitrobenzyl)-N-acryloyl glycinamide), P(AM-co-NBNAGA), copolymer solution was prepared via reversible addition fragmentation chain transfer (RAFT) polymerization using the monomers mixture of AM, NBNAGA, and N,N'- methylene bis-acrylamide (BIS). The obtained polymer solution with viscous, transparent, and flowable appearance contained weak single hydrogen bonding and slight chemical crosslinking in a microscopic perspective. Secondly, without further purification, after irradiation using UV light at 365 nm, poly(acrylamide-co-N-acryloyl glycinamide) (P(AM-co-NAGA)) hydrogel conveniently in situ formed due to the cleavage of o-nitrobenzyl groups and the corresponding emergency of dual hydrogen bonding among “uncaged” dual amide moieties. P(AM-co-NAGA) hydrogel depicted both favorable temperature sensitivity and self-healing properties, then the heating induced in vitro release profiles of doxorubicin (DOX) was analyzed.