Highly selective separation of vanadium over iron from stone coal by oxalic acid leaching

Pengcheng Hu,Yimin Zhang,Tao Liu,Jing Huang,Yizhong Yuan,Qiushi Zheng 한국공업화학회 2017 Journal of Industrial and Engineering Chemistry Vol.45 No.-

In this paper, a novel method was proposed to selectively extract vanadium from stone coal by oxalicacid leaching. Vanadium was leached, but the iron impurity wasmaintained in the leaching residue. Theeffects of leaching conditions on the leaching efficiency of vanadium and iron were investigated foroxalic and sulfuric acid leaching, respectively. For oxalic acid leaching, 71.5% of the vanadium can berecovered with only 3.4% of the iron impurity leached under the leaching conditions: a dosage of H+ of12 mol/kg, a leaching time of 6 h, a leaching temperature of 368 K (95 8C) and a water–mineral ratio of1.5 L/kg. However, under the same conditions, 74.1% of the vanadium and 13% of the iron were leachedduring sulfuric acid leaching. The XRD and FTIR analyses showed that both oxalic and sulfuric acidleaching can destroy the crystal lattice structure of muscovite, resulting in the leaching efficiency ofvanadium without much difference. Further, the SEM-EDS and XPS analyses indicated that very littlepyrite dissolved during oxalic acid leaching, but that much more pyrite dissolved during sulfuric acidleaching. Therefore, oxalic acid leaching can achieve a highly selective separation of vanadium over ironfrom stone coal.

Study on the Pressure-Volume-Temperature Properties of Polypropylene at Various Cooling and Shear Rates

Pengcheng Xie,Huaguang Yang,Tianze Cai,Zheng Li,Yuelin Li,Weimin Yang 한국고분자학회 2018 폴리머 Vol.42 No.2

To understand the pressure-volume-temperature (PVT) properties of polymer in injection process, a dilatometer with high cooling rate (up to 25 oC/s) and shear rate (up to 320 s-1) was developed. The working pressure and temperature of the dilatometer range from 0 to 100 MPa, and from 30 to 300 oC, respectively. With this instrument, a crystalline polymer polypropylene (PP) was employed to study the effects of cooling rate, shear rate, pressure and their coupling effect on its PVT properties. It was demonstrated that the cooling rate showed a significant effect on the PVT properties. With the increase of cooling rate, the transition temperature of PP from melt state to crystallization decreases gradually and the temperature range of crystallization was also extended. Shear increased the transition temperature of PP from melt state to crystallization. Meanwhile, the initial temperature of shear and crystalline segment was shifted to a higher temperature region with increasing shear duration or shear rate. Above the transition temperature, the effect of shear on the PVT properties weakened gradually with increasing the initial temperature. The coupling analysis of cooling and shear processes showed that increase in cooling rate was enhanced the effect of shear on the transition temperature of PP from melt state to crystallization.

No Blind Spot: Network Coverage Enhancement Through Joint Cooperation and Frequency Reuse

Yi Zhong,Pengcheng Qiao,Wenyi Zhang,Fu-chun Zheng 한국통신학회 2016 Journal of communications and networks Vol.18 No.5

Both coordinated multi-point transmission and frequencyreuse are effective approaches to mitigate inter-cell interferenceand improve network coverage. The motivation of thiswork is to explore the manner to effectively utilize the spectrum resourceby reasonably combining cooperation and frequency reuse. The Mat´ern cluster process, which is appropriate to model networkswith hot spots, is used to model the spatial distributionof base stations. Two cooperative mechanisms, coherent and noncoherentjoint transmission (JT), are analyzed and compared. Wealso evaluate the effect of multiple antennas and imperfect channelstate information. The simulation reveals that the proposed approachto combine cooperation and frequency reuse is effective toimprove the network coverage for users located at both the centerand the boundary of the cooperative region.

No Blind Spot: Network Coverage Enhancement Through Joint Cooperation and Frequency Reuse

Zhong, Yi,Qiao, Pengcheng,Zhang, Wenyi,Zheng, Fu-chun The Korea Institute of Information and Commucation 2016 Journal of communications and networks Vol.18 No.5

Both coordinated multi-point transmission and frequency reuse are effective approaches to mitigate inter-cell interference and improve network coverage. The motivation of this work is to explore the manner to effectively utilize the spectrum resource by reasonably combining cooperation and frequency reuse. The $Mat{\acute{e}}rn$ cluster process, which is appropriate to model networks with hot spots, is used to model the spatial distribution of base stations. Two cooperative mechanisms, coherent and non-coherent joint transmission (JT), are analyzed and compared. We also evaluate the effect of multiple antennas and imperfect channel state information. The simulation reveals that the proposed approach to combine cooperation and frequency reuse is effective to improve the network coverage for users located at both the center and the boundary of the cooperative region.

Correlations among Six Hormone-Induced Transcription Factors and the Alcohol Acyltransferase Gene in Apple

Qing-Qing Li,JIN SHENG,Pengcheng Li,Dapeng Li,Cheng-Chao Zheng,Dequan Li,Huairui Shu 한국식물학회 2012 Journal of Plant Biology Vol.55 No.4

Alcohol acyltransferase (AAT) plays an important role in ester biogenesis in ripening fruit. In apple, MdAAT2 is up-regulated in response to treatment with defense-related hormones. We cloned a novel MdAAT2 promoter via thermal asymmetric interlaced PCR (TAIL-PCR). Sequence analysis indicated the presence of salicylic acid (SA)- and methyl jasmonate (MeJA)-responsive elements in the promoter region. To examine further the operational mechanism for transcription factors (TFs) in regulating expression of the MdAAT2 promoter, we isolated and investigated six potential stress-induced TFs -- MdMYB1, MdMYB2, MdMYB6,MdERF1, MdERF2, and WRKY. These were monitored during various stages of fruit development as well as under several hormonal treatments. Reverse transcription-polymerase chain reaction (RT-PCR) analysis showed that all of these TF genes, as well as MdAAT2, were detectable in the stigmas. Levels of expression by MdMYB1, MdMYB2, and MdERF1were significantly correlated with that by MdAAT2 during fruit ontogeny. Moreover, transcription of three TFs (MdMYB1,MdMYB6, and MdERF1) was significantly correlated with that of MdAAT2 upon exposure to ethephon, SA, or MeJA. Sequence analysis demonstrated that CAAT, CCAAT elements,and several MYB transcription factor binding sites (CNGTTmotif,AACCA, and CTAACCA elements) existed in the MdAAT2 promoter region. Using that analysis, we performed modeling of MdMYB1 and MdMYB6 based on PROTEINDNA complex1 and complex3 (PDB Accession Numbers 1H88 and 1H8A). There, similarities were found with the protein complex of CAAT or CCAAT consensus sequences. Thus, we propose that two TFs -- MdMYB1 and MdMYB6-- are directly or indirectly involved in the activation of MdAAT2 expression in apple fruit.

HPLC Determination and Steady-State Bioavailability Study of Levodropropizine Sustained-release Tablets in Dogs

Lin Yan,Tongling Li,Rongqin Zhang,Xiaohong Xu,Pengcheng Zheng 대한약학회 2006 Archives of Pharmacal Research Vol.29 No.6

A simple HPLC method using UV detection was developed and validated for the determination of levodropropizine (LDP) in dog plasma. The sample was prepared for injection using a liquid-liquid extraction method with 1-phenypiperazine as the internal standard. The mobile phase was methanol - diethylamine solution (0.05 M) (20:80, v/v, pH adjusted to 3.0 with H3PO4) with a detection wavelength of 240 nm. The limit of quantitation (LOQ) of LDP in a biological matrix was determined to be 25.25 ng/mL. The calibration curve was linear across the concentration range of 25.25 to 2020 ng/mL. The intra-day and inter-day precision values (CV %) were within 7% and accuracy (R.E. %) was within 6% of the nominal values for medium (252.5 ng/mL) and high (2020 ng/mL) LDP concentrations. For the LDP concentration at the LOQ, the intra-day and inter-day precision and accuracy were within 20% and 10%, respectively. The average absolute recovery for LDP was 70.28%. This method was successfully used to analyze plasma samples in a steady-state bioavailability study of a newly developed sustained-release LDP tablets (SR) using immediate-release tablets (IR) as the reference. The relative bioavailability of the SR was determined to be 106.3 ± 12.8% (n=6). The Cmax of the SR was significantly lower (P<0.05), and the tmax was significantly longer than that of the IR (P<0.05). The results of ANOVA and two one-sided tests indicated that the SR exhibited acceptable sustained release properties and was bioequivalent to the IR.

HPLC Determination and Steady-State Bioavailability Study of Levodropropizine Sustained-release Tablets in Dogs

Yan, Lin,Li, Tongling,Zhang, Rongqin,Xu, Xiaohong,Zheng, Pengcheng The Pharmaceutical Society of Korea 2006 Archives of Pharmacal Research Vol.29 No.6

A simple HPLC method using UV detection was developed and validated for the determination of levodropropizine (LDP) In dog plasma. The sample was prepared for injection using a liquid-liquid extraction method with 1-phenypiperazine as the internal standard. The mobile phase was methanol - diethylamine solution (0.05 M) (20:80, v/v, pH adjusted to 3.0 with $H_3PO_4$) with a detection wavelength of 240 nm. The limit of quantitation (LOQ) of LDP in a biological matrix was determined to be 25.25 ng/mL. The calibration curve was linear across the concentration range of 25.25 to 2020 ng/mL. The intra-day and inter-day precision values (CV%) were within 7% and accuracy (R.E. %) was within 6% of the nominal values for medium (252.5 ng/mL) and high (2020 ng/mL) LDP concentrations. For the LDP concentration at the LOQ, the intra-day and inter-day precision and accuracy were within 20% and 10%, respectively. The average absolute recovery for LDP was 70.28%. This method was successfully used to analyze plasma samples in a steady-state bioavailability study of a newly developed sustained-release LDP tablets (SR) using immediate-release tablets (IR) as the reference. The relative bioavailability of the SR was determined to be $106.3\;{\pm}\;12.8%$ (n=6). The $C_{max}$ of the SR was significantly lower (p<0.05), and the $t_{max}$ was significantly longer than that of the IR (p<0.05). The results of ANOVA and two one-sided tests indicated that the SR exhibited acceptable sustained release properties and was bioequivalent to the IR.