ISSN 0253-2778

CN 34-1054/N

2014 Vol. 44, No. 11

Display Method:
Estimation of the number of primary factors based on residual matrix variance ratio
LU Wei, SHAO Limin
2014, 44(11): 881-886. doi: 10.3969/j.issn.0253-2778.2014.11.001
A method of estimating the number of primary factors based on residual matrix variance (RVR) was presented, whose criterion is the difference between reduced matrices after deducting different numbers of factors. Meanwhile, the results of the simulated and experimental data obtained by using RVR were presented. A comparison between RVR and several typical methods indicates that RVR has good performance in estimating primary factors.
Enrichment of denitrifying anaerobic methane oxidation microbes in a hollow fiber membrane bioreactor
QIAN Zhusheng, FU Liang, DING Jing, DING Zhaowei, Raymond J Zeng
2014, 44(11): 887-892. doi: 10.3969/j.issn.0253-2778.2014.11.002
The process of denitrifying anaerobic methane oxidation (DAMO) can be catalyzed by DAMO bacteria called Methylomirabilis oxyfera with or without the involvement of DAMO archaea. Enrichment of DAMO microbes often takes a long time (7~18 months) to show a faint denitrification function in reported DAMO process. This study aimed to fast enrich DAMO microbes in a hollow fiber membrane bioreactor (HFMB) as the special structure of hollow fiber can increase the mass transfer of methane. It is found that HFMB shows DAMO activity in a shorter period of time (<3 months) and the denitrification rate reaches 50 mg·L-1·d-1 NO3--N. The next-generation DNA sequencing on the microbes in HFMB shows that Anaerolineaceae, Azospira, CL500-3 are dominant with 3908%, 1368% and 1154% of the total microbes, respectively. Meanwhile, Methylomirabilis (DAMO bacteria) and Methanosarcina (DAMO archaea) are only 002% and 013%, respectively. It is speculated therefore that the DAMO process in HFMB may have been catalyzed by other microbes that are different from the known DAMO microbes.
Fabrication and nanostructural tuning of a novel GSH-responsive triblock polyprodrug amphiphiles
WEI Yijun, YIN Liuyue, HU Xianglong
2014, 44(11): 893-903. doi: 10.3969/j.issn.0253-2778.2014.11.003
Based on the feature of tumors reduction-responsive milieu, a novel type of glutathione (GSH)-responsive polyprodrug amphiphiles, PCPTM-b-PEG-b-PCPTM triblock copolymers was fabricated, with CPT loading content higher than 50% (mass fraction). It is found that aqueous self-assembly of PCPTM-b-PEG-b-PCPTM is strongly dependent on common solvent compositions, affording two kinds of distinct nanostructures, staggered lamellae and large compound micelles determined by TEM and SEM analysis with the common solvent to be 1,4-dioxane and DMF, respectively. Further cellular experiments reveal that both staggered lamellae and large compound micelles possess relatively high rates of tumor cellular internalization and effective anticancer performance.
Study on the relationship between lightning activities and thunderstorms over the high-latitude regions in Northeast China
GAO Yingying, ZHU Baoyou, MA Ming
2014, 44(11): 904-912. doi: 10.3969/j.issn.0253-2778.2014.11.004
The relationship between lightning activities and summer thunderstorms in the summer time during 2009~2010 in Northeast China was investigated by utilizing VLF/LF multi-station network lightning data, Doppler radar echo data and NCEP/CPC Global IR cloud-top temperature data. The results show that most of the lightning occurred in regions where the radar echo exceeded 40 dBz, and the maximum height of 30 dBz radar echo of lightning-producing thunderstorms exceeded 6 km. During the evolution of thunderstorms, the peak time of flash rate slightly lagged behind the peak time of the max height of 30 dBz radar echo. The flash rate tended to increase exponentially with the maximum height of 30 dBz radar echo. Lightning was observed to occur in regions with an IR cloud-top temperature of 210~240 K, and it seems that the IR cloud-top temperature of lightning-producing thunderstorms during the dissipation phase was warmer than that during other stages and that the height of cloud top was lower.
Hydro-chemical characteristics of groundwater in centralized drinking water sources and its quality assessment in northern Anhui Province
HU Yunhu, ZHANG Fuhai, NIU Zhiyuan, DONG Zhongbing, LIU Guijian, GAO Lianfen
2014, 44(11): 913-920. doi: 10.3969/j.issn.0253-2778.2014.11.005
Thirty-one water samples from northern Anhui Province were collected and analyzed. The descriptive statistics method and Piper trilinear diagrams were used to study the hydro-chemical characteristics and distribution of groundwater in northern Anhui Province, and the relationship between the main ions and the trace elements were studied. The single factor evaluation and integrated evaluation methods were used to evaluate the quality of the groundwater. The results show that the cations of the groundwater in this area are mainly Ca2+ and Na+, while the anions are mainly HCO3-, and the chemical types are mainly HCO3-Ca and HCO3-Na. The results of the single factor evaluation of the groundwater quality indicate the indicators include TDS (total dissolved solids), NO3-, F-, NO2-, and NH4+. The results of integrated environmental quality assessment show that the quality of the groundwater samples from this area are invariably of categories Ⅱ and Ⅲ.
Heat transfer analysis of a multi-borehole heat exchanger of ground source heat pump systems
TANG Changfu, ZHANG Wenyong, ZHU Wenwei, YU Xianzhong, LIU Guijian
2014, 44(11): 921-925. doi: 10.3969/j.issn.0253-2778.2014.11.006
Based on the line source theory and superposition principle, a mathematical model for heat transfer underground with a multi-borehole heat exchanger of ground source heat pump (GSHP) was developed and solved by the Laplace transformation and numerical inverse technique. Variations of heat transfer capacity and outlet fluid temperatures were studied with uniform inlet fluid temperatures for all boreholes. It is found that at an early stage, performance of each of the multiple boreholes is the same as that of a single borehole. However, performance of the multi-borehole heat exchanger is reduced due to the interference among the boreholes. The average heat flux is lower and outlet fluid temperature is higher than that of a single borehole. In addition, the interference can be weakened when the spacing of the multiple boreholes is larger.
Distribution characteristics and environmental significance of nitrogen and phosphorus in the Huainan coal mining subsidence area
LIU Xiangxiang, CHENG Hua, ZHENG Liugen, JIANG Chunlu, LI Chao, CHEN Yongchun, AN Shikai
2014, 44(11): 926-932. doi: 10.3969/j.issn.0253-2778.2014.11.007
With extensive coal mining, the water coverage of coal mining subsidence areas tends to expand rapidly. Seven typical subsidence water areas in Huainan mining area were selected. Then their water quality indicators were measured, which included total nitrogen (TN), total phosphorus (TP), ammonia nitrogen (NH4+-N), nitrate nitrogen (NO3--N), etc., and the water quality was assessed. The results show that: ① the mean contents of TN, NH4+-N, NO3--N and TP are 304, 061, 061 and 016 mg/L, respectively. The nitrogen and phosphorus load was serious in the studied area. ② The distributions of TN in Huainan coal mining subsidence area are: Xinzhuangzi (558 mg/L)>Panyi (407 mg/L)>Guqiao (277 mg/L)>Pansan (179 mg/L)>Zhuji and Panbei (147 mg/L)>Paner (117 mg/L). The distributions of TP are: Pansan (029 mg/L)>Xinzhuangzi and Zhuji (020 mg/L)>Guqiao (017 mg/L)>Panbei (014 mg/L)>Panyi (011 mg/L)>Paner (005 mg/L). The distribution of TN and subsidence time show good positive correlation, while there is no obvious regularity in the distribution of TP. ③ Data analysis indicates that TN and NH4+-N have good positive correlation. Temperature, dissolved oxygen, pH have some correlation with nitrogen and phosphorus, respectively. The evaluation results of the comprehensive water quality identification method show that the concentration of nitrogen and phosphorus is basically at level Ⅲ or below in the water quality standards, and the most important pollution factor is TN, followed by NH4+-N.
Study on the heterogeneous characterization method of the internal sedimentary cycle in sand-gravel body reservoir
TIAN Xuanhua, YANG Yong, LU Zhengyuan, HU Gang
2014, 44(11): 933-942. doi: 10.3969/j.issn.0253-2778.2014.11.008
On the basis of the permeability curve of a single sedimentary cycle of the single well, a new heterogeneous characterization method of the internal sedimentary cycle in sand-gravel body reservoir was presented, which was named permeability curve method. First, the fundamental concepts were defined in the permeability curve of a single sedimentary cycle of the single well in sand-gravel body reservoir, which included base line, protrusion and protrusion area. Second, the heterogeneous characterization parameters A and B were founded. Thirdly, four theoretical models were built with the order of increasing heterogeneity. Fourthly, using the four theoretical models and other static, dynamic parameters such as reserves abundance and initial production of a single well, the comprehensive evaluation system which could characterize the heterogeneity of the internal sedimentary cycle in sand-gravel body reservoir was established. The case research results prove that, compared with the traditional parameter characterization method, the permeability curve method has significant advantages in heterogeneous characterization and effectiveness evaluation of reservoir.
Expression of HsCRY in insect cells and research into its binding state with FAD by NMR
WANG Xiaoming, WANG Jiarong, LI Yan, WANG Yujuan
2014, 44(11): 943-951. doi: 10.3969/j.issn.0253-2778.2014.11.009
Cryptochrome (CRY) is a kind of protein sensitive to blue light, and the radical pair formed between the conserved tryptophan triad and cofactor flavin adenine dinucleotide (FAD) plays a central role in mediating circadian clock and magnetoreception. The full-length 1 761 bp DNA of HsCRY1 was cloned from HeLa cell using RT-PCR. Eukaryotic expression vector HTA-HsCRY1 was constructed and verified through colony PCR and sequencing, and it was then transformed into DH10Bac to obtain recombinant bacmid. Bacmid-HsCRY1 was obtained through picking white colonies and PCR analysis. Insect sf9 cells were transfected by Bacmid-HsCRY1 to produce target protein. CRY was analyzed by Western Blot and purified by nickel affinity chromatography with 100 mmol/L and 200 mmol/L imidazole. Three conserved Trp related to electron transfer were predicted by alignment of CRY homologies, and the mutants were also expressed through Bac-Bac baculovirus expression system. The binding state between protein and cofactor flavin adenine dinucleotide was detected by 31P NMR. Compared with the 31P spectrum of free FAD, the chemical shift change of FAD binding with HsCRY1 and mutant3 (W397) was observed, while no chemical shift was observed for FAD binding with mutant1(W320) and mutant2(W374). These results demonstrate that HsCRY1 and its mutants are successfully expressed through Bac-Bac baculovirus expression system, and that mutation affects the binding state of FAD with protein.
Study on the low frequency instability in the near wake of a circular disk
ZHANG Xintai, YANG Jianzhi, GU Hailin, QIAN Wanyi, LIU Minghou
2014, 44(11): 952-959. doi: 10.3969/j.issn.0253-2778.2014.11.010
Based on data of LES (large eddy simulation) and hot wire anemometry, the low frequency instability in the near wake of a circular disk at Re=104 was studied by wavelet analysis and FFT method. It is found that, besides Kelvin-Helmholtz frequency StKH≈16 and vortex shedding frequency StV≈014, there are two low frequencies, namely StL1≈002 and StL2≈003. Further study shows that the two frequencies are correlated with the azimuthal motion of the vortex shedding location and the pumping motion of the recirculation region, respectively. The study presents a reasonable explanation of the scattering in the value of the low frequency in the near wake of the bluff body.
Effects of different parametrization strategies to flamelet modeling accuracy
WU Yuxin, YE Taohong
2014, 44(11): 960-966. doi: 10.3969/j.issn.0253-2778.2014.11.011
Application of flamelet model can lead to great reduction in computational cost through dimensional reduction of chemistry reacting system during combustion simulation. Steady laminar flamelet model was introduced into plan flame simulation, with both parametrization form (Z,χZ) and (Z,Yc) applied. A general flamelet transformation was performed to explain the effects of different parametrization strategies to flamelet modeling accuracy by analyzing manifolds characteristic for planar flames. Solutions obtained by direct numerical simulation (DNS) were introduced as a reference to verify modeling accuracy. Comparisons between solutions obtained by different parametrization strategies show that application of (Z,Yc) parametrization form can achieve more accurate solutions close to the DNS ones than (Z,χZ) form.