Beijing Forestry UniversityBeijing
Beijing Forestry UniversityBeijing
Liu Z.,Beijing Forestry UniversityBeijing |
Zhang Y.,Beijing Forestry UniversityBeijing |
Fa K.,Beijing Forestry UniversityBeijing |
Qin S.,Beijing Forestry UniversityBeijing |
She W.,Beijing Forestry UniversityBeijing
Catena | Year: 2017
Modifications of rainfall patterns are expected to accompany global climate changes. It has been suggested that in dry regions changes in soil carbon emission induced by precipitation will affect soil carbon storage and atmospheric CO2concentration. However, our understanding of the responses of soil carbon emission [often as soil respiration (RS)] to rainfall pulses is still limited regarding changes in soil respiration components [heterotrophic respiration (RH) and autotrophic respiration (RA)] and under different precipitation patterns in arid and semiarid ecosystems. To evaluate the variations in soil carbon emission in response to rainfall pulses, we measured RSand its components in situ before/after precipitation in the Mu Us Desert, China. Rates of RSand its components were significantly enhanced by rainfall pulses, but gradually reverted thereafter. Moreover, the magnitudes of diel hysteresis for RS, RH, and RAwith respect to soil temperature (TS) were modified by precipitation, and the effects of rainfall pulses on RSwere influenced by antecedent soil water availability. In addition, the ratio of respiration components was changed by individual precipitation events, with an increase in the amount of each rainfall pulse causing a decrease in the proportion of RHto RS. Our results indicate that rainfall pulses in desert ecosystems have a major impact on soil carbon emission via changes in the magnitude and ratio of respiration components. We accordingly suggest that greater carbon emission and alterations in respiration components may occur with more extreme precipitation in desert ecosystems. © 2017 Elsevier B.V.
Lu X.,Beijing Forestry UniversityBeijing |
Dun H.,Beijing Forestry UniversityBeijing |
Lian C.,Beijing Forestry UniversityBeijing |
Zhang X.,Beijing Forestry UniversityBeijing |
And 2 more authors.
Plant Physiology and Biochemistry | Year: 2017
Plant miR164 family is highly conserved and miR164 members regulate conserved targets belonging to NAC transcription factors. Our previous studies have revealed that peu-miR164a–e and its target gene POPTR_0007s08420 participate in abiotic stress response in Populus euphratica according to deep sequencing and degradome sequencing. In this study, miR164 family comprises six members that generate two mature products (miR164a–e and miR164f) and target seven NAC genes in P. euphratica. Co-expression in Nicotiana benthamiana and 5' RACE confirmed that peu-miR164 directs PeNAC070, PeNAC012 and PeNAC028 mRNAs cleavage. Expression profiles of primary peu-miR164 a/b/c/d/e bear similarity to those of peu-miR164a–e, whereas PeNAC070 and PeNAC081 showed inverse expression patterns with peu-miR164a–e under abiotic stresses. Existence of cis-acting elements in PeNAC070 promoter (ABRE,MBs, Box-W1, GC-motif, and W-box) and in peu-MIR164b promoter (HSE) further confirmed different responses of peu-miR164 and PeNAC070 to abiotic stresses. Histochemical β-glucuronidase (GUS) staining revealed that GUS activities increased when ProPeNAC070::GUS transgenic Arabidopsis plants were exposed to NaCl, mannitol and abscisic acid (ABA), whereas GUS activity of Propeu-MIR164b::GUS plants decreased under ABA treatment. Subcellular localization and transactivation assays showed that PeNAC070 protein was localized to the nucleus and exhibited transactivation activity at the C-terminal. Overexpression of PeNAC070 in Arabidopsis promoted lateral root development, delayed stem elongation, and increased sensitivity of transgenic plants to drought and salt stresses. This study aids in understanding the adaptability of P. euphratica to extreme drought and salt environment by analysing tissue-specific expression patterns of miR164-regulated and specific promoter-regulated PeNAC genes. © 2017 Elsevier Masson SAS
Jiang D.,North University of China |
Jiang D.,Beijing Materials University |
Cui S.,Beijing Materials University |
Xu F.,Beijing Forestry UniversityBeijing |
Tuo T.,North University of China
Construction and Building Materials | Year: 2015
Abstract To make effective use of plant leaves as an environment-friendly heat-insulating building material, our research group has tested five poplar leaf modification methods to improve compatibility between leaf fibres and cement-based materials. The work involved testing water absorption of before and after modification of leaf fibres, the setting time and hydration heat of the fibre-cement paste, and analysed the mechanisms and effect of fibre modification methods on compatibility between fibres and cement-based materials. The results show that processing of fibres with surface coating and dipping methods improved compatibility between fibres and cement-based materials to some extent and in different aspects. Overall, the following three methods gave superior performance: pure acrylic polymer emulsion spraying, sodium silicate solution spraying and water dipping. © 2015 Elsevier Ltd.
Wang K.,Tsinghua University |
Ma L.,Tsinghua University |
Xu X.,Beijing Forestry UniversityBeijing |
Wen S.,Tsinghua University |
Zhang Y.,Tsinghua University
Langmuir | Year: 2015
Triboluminescence (TL) has gained increasing attention in the past two decades due to its potential for many applications such as an in situ damage sensor, X-ray source, spectroscopic probe, and optical switch. So far the mechanisms by which TL is excited are not well understood. We have investigated the TL emitted during the sliding contact between silica wafer and YSZ (yttria-stabilized zirconia) wafers in CO2 gas, ambient air, and vacuum. We discovered that the mean intensity of photons emitted in CO2 gas is nearly a hundred times stronger than that in air. TL induced in the sliding experiment is proposed to be due to a combination of chemical luminescence, impurities and vacancies luminescence. In addition, the intensity of the light emission of YSZ may be controlled by changing the concentration of CO2 gas. © 2015 American Chemical Society.
Xia C.,University of North Texas |
Wang L.,Beijing Forestry UniversityBeijing |
Dong Y.,Beijing Forestry UniversityBeijing |
Zhang S.,Beijing Forestry UniversityBeijing |
And 3 more authors.
RSC Advances | Year: 2015
Epoxidized soybean oil (ESO) is an environmentally friendly cross-linking agent derived from soybean, having multiple epoxy groups in its molecules. It can effectively improve tensile strength and water resistance of soy protein isolate (SPI)-based films. The properties of the SPI-based films were characterized by X-ray diffraction and attenuated total reflectance Fourier transform infrared spectroscopy. The best performance of the SPI-based films was achieved when the ESO addition was 2.5%, for which tensile modulus, tensile strength and 10% offset yield strength were increased to 265.0 MPa, 9.8 MPa and 6.8 MPa, respectively. Compared to untreated SPI-based films, these were increases of 695.6%, 139.8%, and 246.6%, respectively. However, the elongation at break was decreased by 67.6% due to the cross-linking between SPI and ESO. The SPI-based film modified by 5% ESO had the best water-resistance property and reduced the 24 hour water absorption from 209.1% to 45.9%, which was a significant decrease of 78.1%. © The Royal Society of Chemistry.
Wang X.,Tsinghua University |
Wang X.,Beijing Forestry UniversityBeijing |
Shi G.,Tsinghua University
Physical Chemistry Chemical Physics | Year: 2015
Pristine graphene and chemically modified graphenes (CMGs, e.g., graphene oxide, reduced graphene oxide and their derivatives) can react with a variety of chemical substances. These reactions have been applied to modulate the structures and properties of graphene materials, and to extend their functions and practical applications. This perspective outlines the chemistry of graphene, including functionalization, doping, photochemistry, catalytic chemistry, and supramolecular chemistry. The mechanisms of graphene related reactions will be introduced, and the challenges in controlling the chemical reactions of graphene will be discussed. This journal is © the Owner Societies.
Xue Z.,Beijing Forestry UniversityBeijing |
Sun X.,Renmin University of China |
Li Z.,Shandong University |
Mu T.,Renmin University of China
Chemical Communications | Year: 2015
A controllable synthetic route has been developed for the preparation of chitosan supported Pd catalysts in an ionic liquid, 1-butyl-3-methylimidazolium acetate ([Bmim]OAc), by using compressed CO2 as the anti-solvent and regulator. It was found that the dispersion of Pd particles on chitosan and the catalytic activity of the as-prepared catalysts for the hydrogenation of styrene could be tuned by changing the pressure of CO2. This journal is © The Royal Society of Chemistry.
PubMed | Pennsylvania State University, Beijing Forestry University and Beijing Forestry UniversityBeijing
Type: | Journal: Frontiers in microbiology | Year: 2017
PubMed | Beijing Forestry University and Beijing Forestry UniversityBeijing
Type: | Journal: Frontiers in plant science | Year: 2017
Shrublands are one of the major types of ecosystems in the desert regions of northern China, which is expected to be substantially more sensitive to global environmental changes, such as widespread nitrogen enrichment and precipitation changes, than other ecosystem types. However, the interactive effects of nitrogen and precipitation on them remain poorly understood. We conducted a fully factorial field experiment simulating three levels of precipitation (ambient, +20%, +40%) and with two levels of nitrogen deposition (ambient, 60 kg N ha
Yang J.,Beijing Forestry UniversityBeijing |
Zhang X.,Beijing Forestry UniversityBeijing |
Ma M.,Beijing Forestry UniversityBeijing |
Xu F.,Beijing Forestry UniversityBeijing
ACS Macro Letters | Year: 2015
The biologically inspired dynamic materials offer principles for designing man-made systems by using assembly approach. In this work, the hybrid hydrogels consist of cellulose nanofibrils (CNFs) that combine a mechanically strong skeleton with flexible PEG chains. The distinct gel state is observed at room temperature with G′ > G″ and an order of magnitude higher G′ values from 0.08 to 0.93 kPa upon increasing CNF concentration from 0.2 to 2 wt % at constant 2 wt % PEG. Combined with mechanically strong CNFs and dynamic ionic bridges through amine-terminated tetra-arm PEG adsorption to TEMPO-oxidized colloidal nanofibrils surface, the assembled colloidal hydrogels show high modulus, reversible gel-sol transition, and rapid self-recovery properties. It is envisioned that simply mixing hard CNF and soft polymeric matrix would lead to a facile method to bridge reversible dynamic bonds in a cellulose-based hybrid network and broad cellulose applications in the preparation of high performance supramolecular systems. © 2015 American Chemical Society.