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为提升燃料的综合燃烧品质和性能，进一步降低有害物质排放和缓解温室效应，以燃烧动力学和化学反应机制作为理论基础，采用Chemkin软件将生物柴油替代物和氨气充分融合，模拟并计算氨气掺混比例分别为0、5%、10%、15%、20%的5组燃料在均质压燃发动机模式下燃烧和排放指标的数值，对比分析得到不同掺混比例对发动机燃烧和排放的影响和变化规律。结果表明：随着氨气掺混比例增加，燃料的点火滞燃期有所缩短，缸内燃烧最高温度升高，排温降低；排放方面，NOx的排放升高，CO2、CO和总碳氢化合物（THC）的排放均明显降低；生物柴油掺混氨气的最佳比例为20%，此时发动机功率下降12百分点，NO的单位功率排放升高了0.003 kW-1，而CO2和THC的单位功率排放分别降低了0.01 kW-1和0.001 3 kW-1。综上，生物柴油掺混氨气后改善了燃烧性能，降低了排放量，具有良好的应用前景 In order to improve the comprehensive combustion quality and performance of the fuel, further reduce the emission of harmful substances and mitigate the greenhouse effect, based on the theoretical basis of combustion kinetics and chemical reaction mechanism, the Chemkin software was used to fully integrate the mechanism of biodiesel substitute and ammonia gas, simulate and calculate the combustion and emission values of 5 groups of fuels with the ammonia gas molar ratio of 0, 5%, 10%, 15% and 20% respectively in homogeneous charge compression ignition engine mode. The effects and change rule of different mixing ratio on engine combustion and emission were compared and analysed. The results showed that with the increase of ammonia gas ratio, the ignition delay period of fuel was shortened, the maximum combustion temperature in the cylinder increased, and the exhaust temperature decreased. In terms of emission, NOx emission increased, while CO2, CO and total hydrocarbon (THC) emissions decreased significantly. The optimal ratio of biodiesel blended with ammonia gas was 20%, and under this condition, the engine power decreased by 12 percentage, and the unit power emission ratio of NO increased by 0.003 kW-1, while the unit power emission ratios of CO2 and THC decreased significantly, which were 0.01 kW-1 and 0.001 3 kW-1 respectively. In conclusion, biodiesel blended with ammonia gas significantly improves combustion and reduces emissions, and has good application prospect.

Objective To investigate the mental resilience and childbirth attitudes of primiparous women, and to analysis related influencing factors of childbirth attitudes. Methods A convenient sample of 284 primiparous women were included. A questionnaire survey with general information scale, Connor-Davidson Resilience Scale (CD-RISC) and Childbirth Attitudes Questionnaire (CAQ) were conducted. The Pearson correlation analysis was adopted to investigate the relationship between mental resilience and childbirth attitudes of primiparous women, and multiple linear regression was used to analyze influencing factors of childbirth attitudes. Results Totally 279 valid questionnaires were collected. The total score of CAQ was (34.05 ±5.34), Factor score of tenacity and optimism and overall score of CD-RISC were lower than those of domestic norm(P <0.05). The score of CAQ was negatively associated with strength, tenacity and optimism, respectively (r = 0.138, 0.264, 0.382, P <0.05). Age, family support, outpatient service by midwife, strength, tenacity and optimism were independent factors of childbirth attitudes among primiparous women. Conclusion Given the fear of childbirth among primiparous women, health education and outpatient service by midwives should be carried out for primiparous women, especially those with younger age, poor family support. [ABSTRACT FROM AUTHOR]

Angelica dahurica is a kind of Chinese herbal medicine. The effective components of A. dahurica, commonly known as coumarin, have drawn attention because of their wide spectrum of biological effects that might be mainly related to some chemical components with antispasmodic and analgesic activities like some volatile oils such as isoimperatorin, imperatorin and so on. But it is unclear what the components and mechanism of analgesia in A. dahurica are, and whether there are other substances just like some drug-effective amino acids have also some pharmacological effects can make nothing of it. In this study, the contents and composition of protein amino acids and free amino acids in Chaling A. dahurica of Hunan were determined by amino acid analyzer, and analysised of its amino acid composition. Amongtotal amino acids, 16 kinds of amino acids except for An were detected, and the content of Arg was the highest and accounted for 31.21 % close to 1/3 at the ratio of the total amino acids. The content of the essential amino acid reached 27.01% , and the content of Leu is the highest, and accounted for the ratio of the total amino acids up to 24.14%. A higher proportion of essential amino acid are respectively 73.89 % and 85.78% in total amino acids by the acid-catalysed hydrolysing and free amino acids, in which the content of Arg was the highest as 1.383 g . 100 g-1 , and accounted for 42.24%. The content of gamma aminobutyric acid and ornithine in free amino acid was also to a high content. And in addition, a small amount of homocysteine and anserine free non protein amino acids and peptides were detected. The essential amino acid composition was close to the recommendations of the WHO/FAO uptake value. But Met+Cys had minimum RC value, and was the first limiting amino acid. The results showed that these drug-effective and free amino acids might be one cause that Chaling dahurica has good physiological function. Futhermore, the amino acid composition and ratio of Chaling A. dahuricae were relatively reasonable and according with the human body needs. Based on strengthening the sulfur-containing amino acid, Chaling A. dahurica has potential to develope as a new type of health food of edible and pharmaceutical. In addition, the study will also be a theory basis for further study on the pharmacological effects of dahuricae. [ABSTRACT FROM AUTHOR]

Objective To determine the factors affecting post-operative velopharyngeal function of cleft palate patients aged over two years old. Methods The data on 245 patients, including first visit case records and those in the database, were searched and recorded. Post-operative velopharyngeal function and clinical features, such as cleft ratio, adequate ratio, diagnosis, operative age and method, were analyzed retrospectively. Results Cleft ratio and adequate ratio in the velopharyngeal competence (VPC) group were not statistically different from those in the velopharyngeal incompetence (VPI) group. The difference in VPC rate in different age groups and diagnosis was not significant. The post-operative VPC rates under different methods were significantly different. Conclusion The current therapeutic schedule for patients younger than two years old is inappropriate for patients older than two years old. Cleft ratio is not the main factor affecting postoperative velopharygeal function. Sommerlad-Levator Veli Palatini reconstructional operation combined with sphincter pharyngoplasty can obviously improve the velopharyngeal function of patients aged 2 years old and up. This method should be applied in primary palatoplasty. [ABSTRACT FROM AUTHOR]

Objective To investigate the feasibility and accuracy of length measurement of in vivo teeth by using cone beam CT (CBCT). Methods Before orthodontic extraction, 109 vital premolars from 40 participants were scanned by using CBCT and reconstructed by using InVivoDental software. Buccal-lingual sectional images along the long axis of teeth were then acquired, and the crown, root, and tooth length were measured separately. After careful extraction and fixation, the corresponding length of the same tooth was measured by using a digital caliper. CBCT measurement accuracy was then verified by using physical measurements as reference. Results CBCT and the physical method did not obtain significantly different measurements of the root, crown, and tooth length of experimental teeth (P=0.790, P=0.621, 73=0.657, respectively), and the measurements were found to be consistent. The 95% limits of agreement of root, crown, and tooth length were -1.10 mm to 1.13 mm, -1.00 mm to 0.96 mm, and -1.00 mm to 1.05 mm, respectively. Conclusion The difference between CBCT and the physical method was not significant, and good consistency was shown. CBCT could be applied in noninvasive measurement of in vivo teeth. [ABSTRACT FROM AUTHOR]

To reduce the time value loss of high-value time-sensitive goods and rationalize multimodal transport paths, the influence of the time value of goods on multimodal transport path selection was investigated under uncertain transport demand. Based on the consideration of the value characteristics of the goods, a robust optimization model for multimodal transport paths was established by using the scenario analysis method in the robust optimization method with the objective of minimizing the combined transport cost, time value cost of goods and cost of carbon emission, and the constraints of hard time windows for nodal operations. According to the characteristics of the research problem, a Monte Carlo-based disaster adaptive genetic algorithm was adopted to discuss the model, and a combined transport network consisting of 15 urban nodes and three modes of transport - road, rail and waterway wee used as an arithmetic network for analysis. The results show that the rail distance as a percentage of the total transport distance increases by 17.28% for transport paths taking into account the time value of goods compared to those that do not, resulting in a 12-hour reduction in total transport time and a 16.19% saving in the time value cost of goods. As the average daily decay rate increasing, different transport paths will be chosen in different decay rate ranges. The increasing proportion of rail or road transport distance will be selected to improve transport timeliness and avoid the cost of the time value of goods rising too fast. The uncertainty of demand has increased transport cost, the cost of the time value of goods and the cost of carbon emission by 16.53%, 3.44% and 17.31% respectively. Ultimately it can lead to a 9.65% increase in total transport costs. The results of the study can help decision makers estimate the demand and decay rate based on the actual demand situation and the nature of the goods, and provide a reference for their rational choice of transport paths to avoid excessive loss of time value of the goods. [ABSTRACT FROM AUTHOR]

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In view of the advantages of the geofabriform method damming technology, such as strong applicability, mature technology, and green environmental protection, the technology was used in a tailings pond engineering project. Combining with the tailings pond operation safety control index, the infiltration lines of under different working conditions were calculated, and the safety of the tailings reservoir was analyzed by the simplified Bishop method and the Swedish circular arc (ordinary) method, proving that the safety of the tailings reservoir met the requirements of the specification. The successful application of the geofabriform method damming technology in this tailings pond has reference significance for the design and heightening of other tailings pond. [ABSTRACT FROM AUTHOR]

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The soil denudation caused by concentrated water flow is the primary source of sediment in an eroded rill. Soil detachment rate of sediment loading flow is not only significant for understanding the dynamic process of rill erosion but also an important parameter in soil erosion prediction and soil erosion process modeling. Laboratory simulation is an important method to study rill erosion. Previous researches have suggested an experimental method for rill erosion process study. In their method sediment laden samples are taken from different rill lengths at different time. The rill erosion process along the simulated rill is integrated from the experimental data obtained from different rills lengths. Previous experimental approach is not only disrupted the continuity of rill erosion process but also time consuming. In order to get a better understand of rill erosion process, an improved approach was used for rill erosion process study. In this newly-suggested method, sediment laden samples were taken along the rill simultaneously and the length of the experimental flume was extended to 12 m to ensure sediment loading flow can reach its transport capacity under every hydraulic conditions. A flume platform that was 12 m long and 3 m wide was used as a base to construct a flume that was 12 m long, 0.6 m wide and 0.5 m deep. The flume was sub-divided into six rills that were 0.1 m wide and 12 m long using upright PVC boards to form well-defined rills. A typical silt-loam soil with 22.34% sand, 61.35% silt and 16.31% clay particles from the Loess Plateau of China was used in the experiment. The soil was air-dried and passed through an 8-mm sieve before packed into the simulated rills. The depth of soil in the flume was 25 cm. The bottom 5 cm of the soil was packed to a bulk density of 1 500 kg/m3 to imitate the plow pan layer. The top 20 cm was packed to bulk density of 1 200 kg/m3 as the experimental layer. The soil near the PVC boards was packed slightly higher than the middle to force the water to converge and to minimize the boundary effect. Prior to the experiment, the soil was saturated with a rainfall simulator and allowed to drain for 24 h to ensure homogeneous initial soil moisture content. The experiments were conducted with five slope gradients (5°, 10°, 15°, 20°, 25°) and three inflow rates (2, 4, 8 L/min) with three replicates. Sediment laden samples were simultaneously taken along the rill at the distances of 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 10, and 12 m to determine the rill detachment rate along the rill. Three samples were taken at 1.0-minute intervals for each run. The results indicated that rill detachment rate decreased linearly with sediment concentration and exponentially with rill length (under slope gradients of 15°, 20° and 25°)for all flow rates and slope gradients. That meant the soil detachment rate and sediment concentration moved was opposite to each other. Detachment rate had its maximum value when the sediment concentration was at its minimum value. This variation trend was more obvious at steeper slope gradient and higher flow rate. Both slope gradient and flow rate had a positive influence on detachment rate. Additionally, analytic result indicated that rill detachment rate was a function of sediment concentration, rill length, flow rate and slope gradient. The detachment rate obtained using the traditional method and the ones from this study were compared. The correlation coefficient of the two data sets is 0.917 which indicated that detachment rate can be reliably estimated by the two methods. But the newly-suggested method was more precise, time efficient and easy to operate. The study provided a guideline for rill erosion prevention and establishment of rill erosion prediction model. [ABSTRACT FROM AUTHOR]