Synthesis of ArOTiCl₃ complexes and their application for ethylene polymerization and copolymerization

Wang, Jianwei,Ren, Yingchun,Xu, Sheng,Mi, Puke Techno-Press 2017 Advances in materials research Vol.6 No.3

In this article, novel olefin polymerization catalyst with lower cost and simple synthetic process were developed, $ArOTiCl_3$ complexes [$(2-OMeC_6H_4O)TiCl_3(C1)$, $(2,4-Me_2C_6H_3O)TiCl_3(C2)$, $TiCl_3(1,4-OC_6H_4O)TiCl_3(C3)$, $TiCl_3(1,4-OC_6H_2O-Me_2-2,5)$ $TiCl_3(C4)$] and corresponding $(ArO)_2TiCl_2$ complexes [$TiCl_2(OC_6H_4-OMe-2)_2(C5)$ and $TiCl_2(OC_6H_3-Me_2-2,6)_2(C6)$] have been synthesized by the reaction of $TiCl_4$ with phenol, all these complexes were well characterized with $^1H$ NMR, $^{13}C$ NMR, MASS and EA. When combined with methylaluminoxane (MAO), the $ArOTiCl_3/MAO$ system shows high activity for ethylene copolymerization with 1-octene and copolymer was obtained with broaden molecular weight distribution (MWD). The $^{13}C$ NMR result of polymer indicates that the 1-octene incorporation in polymer reached up to 8.29 mol%. The effects of polymerization temperature, concentration of polymerization monomer and polymerization time on the catalytic activity have been investigated.

Plasma D-dimer Can Effectively Predict the Prospective Occurrence of Ascites in Advanced Schistosomiasis Japonica Patients

Xiaoying Wu,Jianwei Ren,Zulu Gao,Yun Xu,Huiqun Xie,Tingfang Li,Yanhua Cheng,Fei Hu,Hongyun Liu,Zhihong Gong,Jinyi Liang,Jia Shen,Zhen Liu,Feng Wu,Xi Sun,Zhongzheng Niu,An Ning 대한기생충학열대의학회 2017 The Korean Journal of Parasitology Vol.55 No.2

Mechanism of shear strength deterioration of loess during freeze-thaw cycling

Xu, Jian,Wang, Zhangquan,Ren, Jianwei,Yuan, Jun Techno-Press 2018 Geomechanics & engineering Vol.14 No.4

Strength of loess that experienced cyclic freeze and thaw is of great significance for evaluating stability of slopes and foundations in loess regions. This paper takes the frequently encountered loess in the Northwestern China as the study object and carried out three kinds of laboratory tests including freeze-thaw test, direct shear test and SEM test to investigate the strength behaviors of loess after cyclic freeze and thaw, and the correlation with meso-level changes in soil structure. Results show that for loess specimens at four dry densities, the cohesion decreases with freeze-thaw cycles until a residual value is reached and thus an exponential equation is proposed. Besides, little change in the angle of internal friction was observed as freeze-thaw proceeds. This may depend on the varying of soil structure, based on which a clue can be found from the surface morphology and mesoscopic scanning of loess specimens. Clearly we observed significant changes in surface morphology of loess and it tends to aggravate at higher water contents or more cycles of freeze and thaw. Moreover, freeze-thaw cycling leads to obvious changes in the meso-structure of loess including lowering the particle aggregates and increasing both the proportion of fine particles and porosity area ratio. A damage variable dependent on the ratio of porosity area is introduced based on the continuum damage mechanics and its correlation with cohesion is discussed.

Backstepping method based controller design for third-order truck platoon robust to dynamic uncertainty and external disturbance

Jianbo Feng,Liyang He,Yanxue Wang,Jianwei Yang,Hongbin Ren 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.3

The vehicle platoon is subject to dynamic uncertainty and external disturbance, such as air drag and parameter variation in practice, so lack of consideration for those factors can deteriorate control performance. This paper proposes a nonlinear control algorithm based on a novel adaptive backstepping method to cope with the uncertainty and disturbance. The virtual controller in the backstepping method utilizes only the local information of the individual vehicle, rather than the global state information, in the control algorithm design. A third-order vehicle dynamics model was built to incorporate the nonlinearity and the factor of actuation delay. The fuzzy logic system (FLS) is applied to estimate the nonlinearity in vehicle dynamics to facilitate the adaptive control. Five scenarios with different settings were constructed to verify the control performance in the simulation, which indicates the effectiveness and robustness of the controller to dynamic uncertainty and external disturbance.

Efficient photocatalytic degradation of 2-chloro-4,6-dinitroresorcinol in salty industrial wastewater using glass-supported TiO2

Yuan Zhang,Wenwei Jiang,Yongsheng Ren,Baoming Wang,Yong Liu,Quanxian Hua,Jianwei Tang 한국화학공학회 2020 Korean Journal of Chemical Engineering Vol.37 No.3

2-chloro-4,6-dinitroresorcinol (CDNR) is detrimental to the environment and human health owing to its high toxicity and poor biodegradability. To demonstrate the feasibility of photocatalytic degradation of CDNR from industrial salty wastewater by borosilicate glass supported TiO2 under UV light irradiation, borosilicate glass supported TiO2 was prepared successfully by a novel sol-gel route via dip-coating method and characterized by XRD, SEM, FTIR and XPS analysis. The results showed that TiO2 catalyst has the anatase phase structure with crystallite size of 11.5 nm and coats uniformly on the borosilicate glass. Also, the effects of reaction time, pH value, TiO2 dosage, CDNR concentration, and Cl on the degradation efficiency of CDNR were investigated. The results indicated that at pH 2, reaction time 3.5 h, CDNR concentration 10mg/L, NaCl concentration 5.85% (w/w) and TiO2 dosage 1.0 g/L, 97.7% of CDNR was degraded in the presence of Cl, this corresponded to a rate constant of 1.05 h1, illustrating the feasibility of photocatalytic degradation process. This contribution provides a basic investigation regarding the potential application of borosilicate glass supported TiO2.

Shear Strength Behavior of Coarse-Grained Saline Soils after Freeze-Thaw

Songhe Wang,Jiulong Ding,Jian Xu,Jianwei Ren,Yugui Yang 대한토목학회 2019 KSCE JOURNAL OF CIVIL ENGINEERING Vol.23 No.6

The bearing capacity of embankment filled by coarse-grained saline soils will be deteriorated after freeze-thaw, especially when shallow groundwater is included. Direct shear tests were carried out on coarse saline specimens that experienced freeze-thaw cycling. The shear strength of soil specimens at three densities strongly depends upon the normal stress when freeze-thaw is not involved, manifesting as a linear increase. Strength indexes such as cohesion and internal friction angle grow at higher dry densities while little change noted in the residual. The cohesion increases with salt content but lowers with freeze-thaw, especially in initial five cycles, beyond which it stabilizes. The internal friction angle is not associated with the above two factors. The stress-strain curves after freeze-thaw are all strain softening, especially at higher densities. The shear stress exhibits larger influence on particle crushing than freeze-thaw. The modified relative breakage index was calculated based on particle grading curves, and is negatively correlated with the cohesion. An empirical equation was proposed by fitting test data incorporating both salt content and freeze-thaw cycles. Comparisons prove that the calculated cohesion agrees well with the measured data.

Quasi-Fe-/Zn-phthalocyanine polymer derived 2D FeANAC single-atom catalyst for highly efficient ORR and H2O2 sensing

Jingshun Shen,Qi Liu,Qiqi Sun,Jianwei Ren,Xue Liu,Zuoxu Xiao,Chuanwang Xing,Yuexing Zhang,Guangwu Yang,Yanli Chen 한국공업화학회 2023 Journal of Industrial and Engineering Chemistry Vol.118 No.-

A novel two-dimensional (2D) single-atom Fe/N/C catalyst (Fe1Zn30NCPDI) has been prepared uponpyrolyzing a well-designed quasi-Fe-/Zn-phthalocyanine-based polymer (qFePc1@qZnPc30@PDI). In theqFePc1@qZnPc30@PDI precursor, qFePc moieties containing Fe-N4 sites are efficiently segregated by lotsof qZnPc moieties connected together by perylene linkers, which not only leads to the larger specific areain the resulting Fe1Zn30NCPDI but more importantly ensures the in-situ formation of Fe-N4 sites on theself-supporting 2D N-doped carbon backbone. Impressively, Fe1Zn30NCPDI exhibites its superior oxygenreduction reaction (ORR) electro-catalytic activity and peroxidase (POD)-like activity. For ORR in an alkalinemedium, it exhibites a much higher onset potential of 0.97 V and half-wave potential of 0.89 V than20 wt% Pt/C catalyst with good durability of 92 % retention rate after 20000 s. And, Fe1Zn30NCPDI alsoshows better peak power density (86 mW cm2) compared with 20 wt% Pt/C in Zn-air battery. Benefiting from the specific POD-like activity of Fe-N4, the Fe1Zn30NCPDI also shows excellent and selectiveperformance in colorimetric H2O2 sensing, with the ultrafast response (30 s), a low limit of detection(10 nM), and good robustness. This work sheds light on a promising design concept for synthesizing 2Dpolymer-derived single-atom multifunctional catalysts.

Electromembrane separation coupled with urea electrolysis for energy-saving recovery of quaternary ammonium hydroxide from industrial wastewater

Qianqian Fu,Hui Wang,Kunlun Nie,Rongfang Wang,Xuyun Wang,Jianwei Ren 한국공업화학회 2023 Journal of Industrial and Engineering Chemistry Vol.128 No.-

The electrolytic recovery of quaternary ammonium hydroxide (R4NOH) from the wastewater produced inthe process of template-synthesizing molecular sieves has considerable economic benefits. The currentpractices are challenged by the anode corrosion and high operation costs due to harmful chlorine chemicalsin wastewater and high energy consumption. This work proposes a promising energy-saving strategyby combining the recovery of quaternary ammonium hydroxides with urea electrolysis technology. This strategy reduces the anodic oxidation potential and achieves low-energy consumption while avoidingthe formation of hypochlorite ions. Through the laboratory-scale closed membrane electrolysis system(CMES) cycle test, it was found that when the cathode output concentration of 0.5 M was reachedat a current density of 50 mA cm2, the energy consumption was saved by 64.7% compared with the traditionaltechnology. Along with the achievement of the expected recovery rate, the high value-addedR4NOH were recycled. More specifically, the ultra-low voltage of the electrolyze protected the ecosystemby avoiding the corrosion of harmful chlorine chemicals and demonstrated the potential for large-scaleapplications at the reduced process costs.

Design and Characteristic Measurement of 8000 mm Large Aperture Integrating Sphere

Zhao Zhang,Zhi Wan,Xiansheng Li,Hongxing Liu,Jingxu Sun,Zexun Liu,Yamin Wang,Jianwei Ren,Jianyue Ren 한국광학회 2016 Current Optics and Photonics Vol.20 No.4

Integrating spheres play a central role in the radiometric calibration of remote sensors. With thedevelopment of the wide field of view (FOV) remote sensors, aperture diameters of remote sensors arebecoming larger and larger. To satisfy the radiometric calibration requirements of full FOV and fullaperture, an 8000mm diameter large aperture integrating sphere uniform source with a variable exit portwas designed and manufactured. This integrating sphere will be used for pre-launch test and radiometriccalibration of remote satellites. In this paper, optical theories were used to design the output spectralradiance. The LightTools software based on ray-tracing simulation method was used to determine the bestcombination and distribution of inner light sources. A spectral experiment was made to verify the spectralradiance design. To reduce the influence of longtime power-on, a new characteristic measurement methodwas developed to obtain the radiation characteristic of the integrating sphere, which could greatly improvethe measuring efficiency. This method could also be applied to measure other large aperture uniformsources. The obtained results indicate that the spatial uniformity is 98.35%, and the angular uniformityat center position is 98.78%.