ABSTRACT
Pubei Block, which is a subdivision of Daqing Oilfield, presents a challenging environment for conformance control due to its high temperature (average 80 °C) and salinity (13,451 mg/L), making it difficult for the polyacrylamide-based gel to maintain the necessary gel strength. To address this issue, this study aims to evaluate the feasibility of using a terpolymer in situ gel system that provides greater temperature and salinity resistance and pore adaptation. The terpolymer used here consists of acrylamide, acrylamido-2-methylpropane sulfonic acid, and N,N'-dimethylacrylamide. We determined that a formula with a hydrolysis degree of 15.15%, a polymer concentration of 600 mg/L, and a polymer-cross-linker ratio of 2.8 yields the greatest gel strength. The hydrodynamic radius of the gel was found to be 0.39 µm, indicating no conflict with the pore and pore-throat sizes determined by the CT scan. In the core-scale evaluation, the gel treatment improved oil recovery by 19.88%, of which 9.23% was through gelant injection and 10.65% through post water injection. A pilot test began in 2019 and has continued for 36 months until now. Within this period, the oil recovery factor increased by 9.82%. The number is likely to keep going up until the water cut (so far 87.4%) reaches the economic limit.
ABSTRACT
Floral initiation is a major phase change in the spermatophyte, where developmental programs switch from vegetative growth to reproductive growth. It is a key phase of flowering in tea-oil trees that can affect flowering time and yield, but very little is known about the molecular mechanism of floral initiation in tea-oil trees. A 12-year-old Camellia oleifera (cultivar 'changlin53') was the source of experimental materials in the current study. Scanning electron microscopy was used to identify the key stage of floral initiation, and transcriptome analysis was used to reveal the transcriptional regulatory network in old leaves involved in floral initiation. We mined 5 DEGs related to energy and 55 DEGs related to plant hormone signal transduction, and we found floral initiation induction required a high level of energy metabolism, and the phytohormones signals in the old leaves regulate floral initiation, which occurred at stage I and II. Twenty-seven rhythm-related DEGs and 107 genes associated with flowering were also identified, and the circadian rhythm interacted with photoperiod pathways to induce floral initiation. Unigene0017292 (PSEUDO-RESPONSE REGULATOR), Unigene0046809 (LATE ELONGATED HYPOCOTYL), Unigene0009932 (GIGANTEA), Unigene0001842 (CONSTANS), and Unigene0084708 (FLOWER LOCUS T) were the key genes in the circadian rhythm-photoperiod regulatory network. In conjunction with morphological observations and transcriptomic analysis, we concluded that the induction of floral initiation by old leaves in C. oleifera 'changlin53' mainly occurred during stages I and II, floral initiation was completed during stage III, and rhythm-photoperiod interactions may be the source of the main signals in floral initiation induced by old leaves.
Subject(s)
Camellia , Camellia/genetics , Camellia/metabolism , Trees/genetics , Gene Expression Profiling , Flowers/metabolism , Plant Leaves/genetics , Plant Leaves/metabolism , Plant Growth Regulators/metabolism , Tea/metabolism , Transcriptome , Gene Expression Regulation, PlantABSTRACT
Time response and light yield are two of the most important features of a scintillation detector, and are mostly determined by the luminescence properties of the scintillator. Here we have investigated the radioluminescence (RL) characteristics of a single-crystalline hybrid lead halide perovskite at both room temperature and low temperature. A dual-channel single photon correlation (DCSPC) system with a vacuum chamber is employed for the measurement. A rise time faster than 100 ps and several times enhancement of the crystal scintillation performances at low temperature have been observed. These behaviors demonstrated that bulk solution-grown single crystals of hybrid lead halide perovskites (MAPbCl3 and Br-doped MAPbBr0.08Cl2.92, where MA = CH3NH3) can serve as stable scintillating materials for pulsed gamma detectors. In addition, this work provides a pathway for perovskite application and also attracts attention to investigating low-temperature scintillators.
ABSTRACT
Lutetium-yttrium oxyorthosilicate doped with cerium (LYSO:Ce) is a widely used scintillator, and the study of its nonlinear behavior under high excitation density is very significant owing to its direct influence on radiation measurements. Using a 266 nm ultraviolet laser to excite an LYSO:Ce crystal, the relationship between the photoluminescence (PL) light yield and excitation density was studied by Z scan experiments. The excitation threshold of the LYSO:Ce was obtained, which is about 2.3 J cm-3. Picosecond transient absorption of LYSO:Ce at 800 nm was obtained and used to analyze the dynamic process of carriers. The physical mechanism behind the nonlinearity was discussed and analyzed using the Förster dipole-dipole interaction model, and the interaction characteristic radius was obtained by fitting. This work can help us understand the nonlinearity phenomenon in scintillators and provide references for related radiation detection applications.
ABSTRACT
Scintillators form the chief device for radiation detection, and the study of their characteristics and their related theories is very significant. Specifically, the nonlinear behavior of scintillators under high excitation density has been closely studied owing to its direct influence on the measurements of radiation. We propose a new method to calibrate the nonlinearity of scintillators based on the electron pulse generated by a linear electron accelerator. The nonlinear light yield of several commonly used scintillators versus fluence of 70 MeV electrons in a 10 ps pulse has been measured by adjusting the charge of electron pulses, and the deposition energy threshold is also simulated and calculated. The results show that the deposition energy threshold for the occurrence of 5% nonlinearity is highest for two types of oxide scintillators, viz. LSO and PbWO4, followed by fluoride scintillators, viz. BaF2 and CeF3, and the threshold for a plastic scintillator EJ232 is lowest.
ABSTRACT
A new class of pulsed X-ray detection methods by sensing carrier changes in a diode laser cavity has been presented and demonstrated. The proof-of-principle experiments on detecting pulsed X-ray temporal profile have been done through the diode laser with a multiple quantum well active layer. The result shows that our method can achieve the aim of detecting the temporal profile of a pulsed X-ray source. We predict that there is a minimum value for the pre-bias current of the diode laser by analyzing the carrier rate equation, which exists near the threshold current of the diode laser chip in experiments. This behaviour generally agrees with the characterizations of theoretical analysis. The relative sensitivity is estimated at about 3.3 × 10-17 C â cm2. We have analyzed the time scale of about 10 ps response with both rate equation and Monte Carlo methods.
ABSTRACT
A new detector suitable for measuring high intensity pulsed gamma-ray sources and based upon scattered-electron method is proposed. The detector has a relatively flat energy response in the range of 0.4-5 MeV and works in current mode. The performances of the detector under several conditions were studied by Monte Carlo simulation using the MCNP code. A comparison between calculations and measurements performed using the 1.25 MeV line of Co-60 is also addressed. The experimental signal produced by the detector was thus studied and decomposed into its main components in order to establish the signal-to-noise ratio (SNR). The latter is compared to SNR calculated for other type of detectors.
ABSTRACT
The progress of a 2.45 GHz high-current microwave ion source with permanent magnet for T(d,n)4He reaction neutron generator is reported in this paper. At 600 W microwave power and 22 kV extraction voltage, 90 mA peak hydrogen ion beam is extracted from a single aperture of 6 mm diameter. The beam emittance is measured using a simplified pepper-pot method. The (x,x(')) emittance and the (y,y(')) emittance for 14 keV hydrogen ion beam are 55.3pi and 58.2pi mm mrad, respectively. The normalized emittances are 0.302pi and 0.317pi mm mrad, respectively.
