Response of the Downstream Braided Channel to Zhikong Reservoir on Lhasa River

Lhasa River basin is situated in the southern part of the Qinghai-Tibet Plateau, which is the most important region of economic and social development in Tibet. In order to efficiently utilize water resources in the basin and ease the shortage of regional electric power supply, Zhikong Reservoir was built in the upstream reach of the Lhasa River in 2006. Impoundment of this reservoir evidently affected the morphology and stability of the downstream braided channel below the dam. Yet, little is known about the complex responses of the downstream braided channel to the Zhikong Dam. Landsat images in the 2000–2016 period, together with daily discharges and field observations in the 2017–2018 period, were used to investigate the morphological response of the braided channel to the Zhikong Dam. The downstream Lhasa River below the Zhikong Dam was divided into four reaches (i.e., RS1, RS2, RS3 and RS4) based on the confluence of three downstream tributaries. Results showed that the number and area of central bars in the braided reach closest to Zhikong Dam (RS1) were increased because of main channel incision and water level drop. This increasing trend attenuated along the downstream channel of this reach. Braiding number index of multithread channels in RS1 obviously increased by 3 in one section and reduced by 2 in two sections, while changed in all sections randomly with no pronounced trend along the RS2 to RS3 and RS4 reaches. The average bar area in two focus reaches, RS1_B1 and RS2_B2, 6.0 km and 36.8 km far away to the Zhikong Dam, respectively, followed opposite trends with the former increasing and the later reducing. Furthermore, the mean dissection, landscape dissection and fragmentation shape indices in RS1, showed an increasing trend from 2001 to 2016, indicating the shape of irregular central bars varied greatly because clean water release of Zhikong Dam eroded the downstream braided channel

Microarray analysis of gene expression profiling in Chang Liver cells associated with Lamprey-PHB2 transfection

In order to detect the evolutionary level of prohibitin 2 (PHB2) gene, 10 species were selected to compare the PHB2 amino acid sequence with lamprey PHB2(Lm-PHB2), which was obtained by cloning from Chinese northeast lamprey (Lampetra morii) in present work. The results showed that the PHB2 amino acid sequences of the different species were highly conserved at the PHB domain, but the sequence identity at the N-terminal and C-terminal amino acid sequences was low. Gene chip expression profiles were used to analysis the genes expression alter after the pEGFP-N1-PHB2 plasmids transfected in Chang Liver (CHL)cells. The results showed that there were 270 genes significantly altered expressed in CHL cells, among them, 141 genes were significantly up-regulated and 129 genes were down-regulated, including cell signal transduction, cell cycle regulation, cell proliferation, cell metabolism and apoptosis aspect. The results of Affymetrix Gene Chip Array were verified by real-time quantitative (PCR). The results showed that Cell cycle gene CDC25C, oxidative stress-related genes (CAT, SOD, GST) and anti-apoptotic gene HAX1 expression were significantly altered after transfected pEGFP-N1-Lm-PHB2 plasmids in CHL cells

Sedimentation Rate and Sedimentary Break in Tidal Deposits

Based on the study of tidal laminae of non tidal inlet in the Wenchang Formation of northern Zhejiang Province and at the muddy coast facing open sea in the Yangtze Delta region,the sedimentation rates have been calculated,which are close to that of similar study abroad.Field observation and research of coast pragradation rate and tidal flat sedimentation show that the calculated sedimentation rates are unreasonable.The investigation of present tidal flat in the Yangtze Delta reveals that tidal laminae are formed and reworked during a simidiurnal tidal cycle,and laminae preserved in the layer of sixteen days observation cover only 10% of that could be formed,other 90% have been eroded.The small sequence composed of sandy and muddy layers is a storm sequence,which is formed in the condition of alternation of storm and calm weather.Preservation of the small sequence covers about 10% of that could be formed,and other 90% are reworked.The laminae in the small sequence disappeared when the sandy and muddy layers eroded,so that the laminae preserved in tidal flat sequence are only 0 2% of that could be created.Reworked laminae and layer only have erosion surfaces,i.e.diastems.The attention should be paid to the sedimentary breaks,when we are doing high resolution study of the tidal deposits

Open-Coast Intertidal Deposits and the Preservation Potential of Individual Laminae: A Case Study from East-Central China

Monitoring of sedimentation and erosion was conducted on an open coastal tidal flat on the southern flank of the Yangtze delta. Various elevation references were established in the intertidal zone and monitored intensively for 4 months in order to examine fortnightly and seasonal (calm weather and storm season) sedimentation and erosion. Longer term (100 years) sedimentation and preservation were investigated through examination of cores and trenches. Two different vertical grouping patterns of tidal bedding were distinguished with thinner and thicker sandy laminae. The number of sand-dominated layers and individual muddy and sandy lamina in the cores were compared with theoretically derived sedimentation rates in order to assess long-term preservation potential. Waves, especially high storm waves, have a significant influence on sedimentation and the preservation of intertidal deposits along the open-coast tidal flat. Monitoring during one season indicated that the sand-dominated layer was directly related to storm deposits, while the mud-dominated layer was deposited during calm weather conditions. The variation in sandy lamina thickness was not related to spring–neap tidal cycles during the monitoring period. The assumption of 100% preservation of sandy laminae deposited during every tidal cycle, which has been assumed in previous time-series analyses for the identification of palaeotidal periodicity, was found to be unrealistic along this open-coast tidal flat. Preservation potential decreases as temporal scale increases. During one neap–spring tidal cycle, the preservation potential of individual sandy and muddy laminae was of the order of 10%. Over a period of 100 years, the estimated preservation potential of individual laminae, including both calm weather and storm deposits, decreased to 0·2%. The 100-year preservation potential of storm-induced, sand-dominated layers was estimated to be of the order of 10%

Bacterial community composition in the gut content of Lampetra japonica revealed by 16S rRNA gene pyrosequencing.

The composition of the bacterial communities in the hindgut contents of Lampetrs japonica was surveyed by Illumina MiSeq of the 16S rRNA gene. An average of 32385 optimized reads was obtained from three samples. The rarefaction curve based on the operational taxonomic units tended to approach the asymptote. The rank abundance curve representing the species richness and evenness was calculated. The composition of microbe in six classification levels was also analyzed. Top 20 members in genera level were displayed as the classification tree. The abundance of microorganisms in different individuals was displayed as the pie charts at the branch nodes in the classification tree. The differences of top 50 genera in abundance between individuals of lamprey are displayed as a heatmap. The pairwise comparison of bacterial taxa abundance revealed that there are no significant differences of gut microbiota between three individuals of lamprey at a given rarefied depth. Also, the gut microbiota derived from L. japonica displays little similarity with other aquatic organism of Vertebrata after UPGMA analysis. The metabolic function of the bacterial communities was predicted through KEGG analysis. This study represents the first analysis of the bacterial community composition in the gut content of L. japonica. The investigation of the gut microbiota associated with L. japonica will broaden our understanding of this unique organism

Response of the Downstream Braided Channel to Zhikong Reservoir on Lhasa River

Lhasa River basin is situated in the southern part of the Qinghai-Tibet Plateau, which is the most important region of economic and social development in Tibet. In order to efficiently utilize water resources in the basin and ease the shortage of regional electric power supply, Zhikong Reservoir was built in the upstream reach of the Lhasa River in 2006. Impoundment of this reservoir evidently affected the morphology and stability of the downstream braided channel below the dam. Yet, little is known about the complex responses of the downstream braided channel to the Zhikong Dam. Landsat images in the 2000–2016 period, together with daily discharges and field observations in the 2017–2018 period, were used to investigate the morphological response of the braided channel to the Zhikong Dam. The downstream Lhasa River below the Zhikong Dam was divided into four reaches (i.e., RS1, RS2, RS3 and RS4) based on the confluence of three downstream tributaries. Results showed that the number and area of central bars in the braided reach closest to Zhikong Dam (RS1) were increased because of main channel incision and water level drop. This increasing trend attenuated along the downstream channel of this reach. Braiding number index of multithread channels in RS1 obviously increased by 3 in one section and reduced by 2 in two sections, while changed in all sections randomly with no pronounced trend along the RS2 to RS3 and RS4 reaches. The average bar area in two focus reaches, RS1_B1 and RS2_B2, 6.0 km and 36.8 km far away to the Zhikong Dam, respectively, followed opposite trends with the former increasing and the later reducing. Furthermore, the mean dissection, landscape dissection and fragmentation shape indices in RS1, showed an increasing trend from 2001 to 2016, indicating the shape of irregular central bars varied greatly because clean water release of Zhikong Dam eroded the downstream braided channel

Combining the 2.5D FE-BE method and the TMM method to study the vibro-acoustics of acoustically treated rib-stiffened panels

This paper is concerned with the prediction of the vibro-acoustic behavior of rib-stiffened panels treated with multiple layers of porous materials. The acoustically treated rib-stiffened panels are assumed to be uniform and infinitely long in one direction (the longitudinal direction) but the cross-section can have an arbitrary and often complicated shape. Although the two-and-half dimensional structural finite element method (2.5D FEM) and the two-and-half dimensional acoustic boundary element method (2.5D BEM) may be combined to perform the vibro-acoustic prediction, the presence of the multiple layers of acoustic treatment often makes the prediction too time-consuming. More efficient methods are required for such structures and the aim of this paper is to propose such a method. The rib-stiffened panel and the fluid domain containing the incident and reflected sound waves are modelled using 2.5D FEM-BEM while the acoustic treatment layer and the fluid domain containing the transmitted sound waves are dealt with, approximately, using the transfer matrix method (TMM). The coupling of TMM and 2.5D FEM-BEM is formulated in detail. Since the acoustically treated panel is assumed to be flat and baffled, the 2.5D BEM is based on the Rayleigh integral in the wavenumber domain. Meanwhile, the TMM is based on a two-dimensional Fourier transform which implies that the porous layers also extend to cover the baffle; the validity of this assumption is explored. The accuracy and efficiency of the method is compared with a full 2.5D FE-BE method for a homogeneous plate with attached layers of absorbent material. It is shown that the method proposed in this paper can reduce calculation time by about a factor of three compared with the full 2.5D FE-BE method. The proposed method is then applied to study the sound transmission loss (STL) of a typical rib-stiffened panel from a train carriage which is acoustically treated with different porous material layers, demonstrating that the design of the acoustic treatment can have a significant effect on the STL of the panel.</p

Improvement on water tree resistance and electrical properties of XLPE by adopting triallyl isocyanurate

The effect of TAIC (triallyl isocyanurate) on water tree resistance and electrical properties of XLPE (peroxide crosslinked polyethylene) was investigated in this paper. XLPE specimens with different content of TAIC were prepared for hot pressing method. Water blade method results showed that water tree ageing resistance of XLPE was improved obviously by adopting TAIC. The diameters of microvoids in specimens generated by water droplets would be reduced from micron scale to submicron scale due to the existence of TAIC. Contact angle test and Monte Carlo molecular simulation results revealed that water droplets would be disintegrated due to the presence of TAIC. Moreover, the addition of TAIC can also slightly improve the electrical properties of XLPE. The first-principles calculations revealed that an electron-bound state was generated in the band gap of XLPE for bonding with TAIC and formed a deep trap with 2.3eV. It can be concluded that low mixing energy of TAIC and water is an important reason for improving the water tree resistance of XLPE, and its improvement on electrical properties is attributed to the introduction of deep trap