Synthesis of norbornene (NBE) and dimethanooctahydronaphthalene (DMON), respectively, via a Diels–Alder (D–A) reaction or consecutive D–A reaction with ethylene and cyclopentadiene (CPD) from dicyclopentadiene (DCPD) depolymerization as raw materials was an important process route for high value-added utilization of ethylene and C5 resources. The optimal reaction conditions (such as temperature, pressure, and raw material ratio) were obtained via sensitivity analysis, with the results showing that the reaction of ethylene and CPD was more difficult than that of NBE and CPD. Response surface analysis was applied to examine the effects of multiple factors (including temperature, molar ratio, and reaction time) on product results. The accuracy of the calculation results was verified through experiments, and the results were consistent with actual. The final selectivity of NEB reached 89%, and that of DMON reached over 95%.
The characteristics of nozzle in artificial rainfall system are modelled and simulated.According to the rain intensity distribution data of the nozzle under different pressures,the curve of the rainfall intensity and the radius is obtained.A plurality of nozzles are used to realize the rain intensity change continuously in the range,the overlap of the effective multi-nozzles radius is used to rain uniformly.A detailed design of the artificial rainfall simulation software is provided.Through the comparative analysis of two layouts,the square arrangement is selected,which can greatly improve the effective area.It provides important guiding significance on the selection and layout of the nozzle and research on artificial rainfall system.
It is reasonable to simulate the hydrologic cycle in regions with drastic land use change using a distributed hydrologic model in the dynamic land use mode (dynamic mode). A new dynamic mode is introduced into an object-oriented modularized model for basin-scale water cycle simulation (MODCYCLE), a distributed hydrologic model based on sub-watersheds, and the hydrological response unit (HRU). The new mode can linearly interpolate data for the years without land use data and consistently transfer HRU water storage between two adjacent years after a land use data update. The hydrologic cycle simulation of the Sanjiang Plain in China was carried out from 2000 to 2014 in the dynamic mode using land use maps of 2000, 2005, 2010, and 2014. Through calibration and validation, the performance of the model reached a satisfactory level. Replacing the land use data of the calibrated model using that of the year 2000, a comparison model in the static land use mode (static mode) was built (i.e., land use unchanged since 2000). The hydrologic effects of land use change were analyzed using the two models. If the land use pattern remained unchanged from 2000, despite the average annual runoff increasing by 4% and the average annual evapotranspiration decreasing by 4% in this region only, the groundwater storage of the plain areas in 2014 would increase by 4.6 bil. m3 compared to that in 2000, rather than the actual decrease of 4.7 bil. m3. The results show that the fluxes associated with groundwater are obviously more disturbed by land use change in the Sanjiang Plain. This study suggests that the dynamic mode should be used to simulate the hydrologic cycle in regions with drastic land use change, and the consistent transfer of HRU water storage may be considered in the dynamic mode.
To explore the difference in clinical efficacy and safety of transvaginal and transumbilical single port laparoscopy for endometrial cancer.We retrospectively included 100 endometrial cancer patients who were admitted to the Fuzhou Second Hospital for surgical treatment from September 2020 to September 2021 and divided them into two groups according to different surgical treatment options. Patients in Group A (48 cases) were treated with transvaginal natural endoscopic surgery (TNES), and those in Group B (52 cases) were with transumbilical single port laparoscopic surgery (TSPLS). The operation time, intraoperative blood loss, time to postoperative exhaust, length of hospital stay, pelvic lymph node dissection, and incision infection rate of two groups were compared. The white blood cell count (WBC), hemoglobin (Hb), hematocrit (Hct) of the two groups of patients before and after the surgery were compared between the two groups, as well as th VAS score of 24 hours after the operation, rate of complications during hospitalization, satisfaction with surgery and quality of life 3 months after surgery.Compared with Group B, the operation time and intraoperative blood loss of Group A patients were markedly increased. The time to postoperative exhaust, length of hospital stay, incision infection rate, VAS score at postoperative 24 h, and complication rate of Group A were significantly lower than that of Group B. In addition, Group A had higher performance on the number of pelvic lymph node dissections, surgical satisfaction and quality of life 3 months after surgery.Transvaginal natural cavity endoscopy had better surgical results with faster postoperative recovery and higher safety compared with TSPLS, making it valuable in clinical application and worthy of further popularization.
In addition to implementing active water resource allocation measures to solve the serious groundwater overexploitation problem caused by large-scale rice planting in the Sanjiang Plain, the reasonable adjustment of rice planting areas is another method of doing so. From the perspective of groundwater recharge and discharge balance, this paper carries out a novel assessment of suitable rice planting areas in the Sanjiang Plain, which is expected to provide a new method for the implementation of land exploitation according to water resource conditions. The technical scheme is as follows: by adjusting the water resource allocation data and rice spatial distribution data in the surface water–groundwater coupled model (baseline model with dynamic land use) in the Sanjiang Plain, static land-use models under different rice planting scales were established. Through simulation and comparison, the rice area that could achieve the balance of groundwater recharge and discharge was considered the suitable rice planting scale in the Sanjiang Plain. The results showed that the average annual change in groundwater storage from 2000 to 2014 simulated by the baseline model was −0.313 billion m3, indicating that there was space for further optimization and adjustment of the rice planting scale in the Sanjiang Plain. By comparing the static land-use models of each year under the current water resource allocation pattern, the rice area of 1.021 million hm2 in 2005 could effectively realize the balance of groundwater recharge and discharge. Under the new water resource allocation pattern of 2035, the water resource conditions in the Sanjiang Plain will be greatly improved, which can support a rice planting scale of 3.058 million hm2 on the basis of ensuring the balance of groundwater recharge and discharge. Our research results can provide a reference for water resource allocation and land-use optimization regulation in the Sanjiang Plain.
Abstract Homogeneous hydrogen transfer reactions of methacrolein (MAL) and isopropanol to methallyl alcohol (MAA) were investigated in batch reactor (Conv. 89%, Select 93.1%) and tubular reactor (Conv. 88.1%, Select 95%) using aluminum isopropoxide (Al(OPr i ) 3 ) as catalyst. Kinetic experiments on hydrogen transfer reactions and reaction order were investigated in batch reactor and tubular reactor. Response surface methodology was applied to optimize the optimum reaction conditions of hydrogen transfer reaction. Purification process of MAA from product mixture after hydrogen transfer reaction was simulated with Aspen Plus software; theoretical stages, reflux ratio, and feed stage of distillation tower were optimized. Density functional theory was used to investigate viable reaction pathway and to probe the catalytic mechanism between reactants and catalyst, including dehydrogenation, coupling, and hydrogenation reaction. Microscopic mechanisms of hydrogen transfer reaction from MAA to MAL were acquired in detail and could be easily extended to other series of hydrogen transfer reaction.
Water movement regularities of seasonal freezing-thawing soil in shallow groundwater were analyzed by both quality and quantity approaches.The results show that: 1) in freezing period,soil water moved upwards,groundwater also supplied to soil water;in thawing period,soil water moved two sides from depth of 20-40 cm,and supplied to groundwater downwards,the whole process led the depth of groundwater down and up,but some lost in groundwater evaporation.2) In every period,soil water above and below 20-40 cm showed different regularities,and water exchange between them was little.3) Amplitude of soil water decreased when depth increased,while deeper layers had larger water flux.4) Too deep of groundwater during freezing process would make supply from groundwater decrease significantly,which would led to decreasing of water storage in freezing layers;but there was no such regularity in thawing process.
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