高氮量硝化棉的脱硝反应动力学研究(英文)

用实时测定凝聚相分解产物的固体原位反应池/快速扫描傅立叶变换红外光谱热技术研究了高氮量硝化棉(14.14%N)的脱硝反应动力学。该反应的动力学参数(活化能和指前因子)用改良的Coats-Redfern法计算。根据所得结果,提出了在403～465K温度范围内描述高氮量硝化棉脱硝反应的微分动力学方程。

高氮量单基药的改性研究

通过对高能改性单基药用的原材料选择、配方设计和能量理论计算 ,结合性能测试结果 ,初步确定了以 NC为主体 ,加入高能添填加剂 ,含能增塑剂等组分所组成的高能改性单基药配方类型 ,试验证明 ,该组成采用溶剂法螺压成型的生产工艺是安全可行的。

三元混合溶剂对高氮含量单基发射药性能的影响

为了提高高氮含量单基发射药硝化棉/二硝基甲苯/二苯胺(NC/DNT/DPA)的力学性能,在醇酮溶剂中外加3%的辅助溶剂(二甲基亚砜(DMSO)、N,N-二甲基甲酰胺(DMF)、环己酮、环己烷、三氯甲烷、乙酸乙酯、乙酸丁酯)形成三元混合溶剂,对高氮量硝化棉进行塑化成型,获得相应的单基发射药。通过扫描电镜观察单基发射药样品的微观结构,采用万能材料试验机、简支梁式抗冲击试验机测试了单基发射药的力学性能,通过密闭爆发器实验研究了辅助溶剂对单基发射药能量及燃烧性能的影响。结果表明:当有辅助溶剂加入时,高氮量单基药的力学性能提高,其中添加3%乙酸丁酯的试样在低温(-40℃)、常温(20℃)和高温(50℃)下试样的抗压强度分别提高了15.7%、4.3%和17.7%,抗冲击强度分别提高了29.9%、96.9%和170.0%;辅助溶剂的加入,对单基发射药的燃烧影响较小;与基础单基发射药相比,三元混合溶剂制备的单基发射药火药力均有小幅下降。

不同氮量全胃肠外营养支持在脓毒症中的应用效果

目的探讨在脓毒症患者中应用不同含氮量的全胃肠外营养支持的价值。方法选取我院收治的80例脓毒症患者,平均分为低氮量组和高氮量组,对比两组营养支持前后的血生化指标、氮平衡和血气指标。结果营养支持后,两组血生化指标(TB、GPT、GOT、BUN、Cr)、氮平衡及血气指标(PaO_2、PaCO_2)比较差异均有统计学意义(P均<0.05)。结论在对脓毒症患者进行营养支持的过程中,干预的起点应为低氮量营养支持,然后再结合患者自身消耗情况调整营养支持方案,可以适当地提高含氮量,在此过程中,需要高度重视对患者各器官功能指标的全面监测,尤其是肺功能和肾功能,以便及时地发现存在的肺、肾功能衰竭等情况,及时地调整营养干预方案,确保患者的生命安全与健康。

Effects of Nitrogen Level and High Temperature Stress on Yield, SPAD Value and Soluble Sugar Content of Early Rice Ganxin 203

This study aimed to investigate the combined effects of nitrogen level （high and ordinary） and high temperature stress （37 ℃, 4 d） at the late panicle ini- tiation stage on yield, SPAD value and soluble sugar content of Ganxin 203, an early rice cultivar. The results showed that under both high and ordinary nitrogen levels, high temperature stress reduced the seed-setting rate, yield per stem, SPAD value and soluble sugar content of Ganxin 203; under both high and ordinary tem- peratures, high nitrogen level increased the seed-setting rate, yield per stem and soluble sugar content of Ganxin 203; the seed-setting rate, yield per stem and yield per plant of Ganxin 203 under high temperature and high nitrogen level were higher than those under high temperature and ordinary nitrogen level. It suggests that ap- propriate high nitrogen level contributes to weakening the negative effects of high temperature stress on rice yield.

Effects of Nitrogen Fertilizer Reduction and Application of Nitrogen Fertilizer as Base Fertilizer on Rapeseed Yield and Nitrogen Absorption

[Objective] The aim was to research effects of N fertilizer reduction and application of N fertilizer （as base fertilizer） on rapeseed yield and N absorption. [Method] Based on Ganyouza No.5, the ratio of N, P2O5 andK2O was set at 1：0.5：0.5; N fertilizers were set involving reduced quantity at 150 kg/hm2 and preferred quantity at 180 kg/hm2; 100%, 80% and 60% of N fertilizers were applied as base fertilizers in the test respectively. In general, field tests were conducted to explore effects of reduced N fertilizer and application of N fertilizer as base fertilizer on rapeseed yield and N absorption. [Resalt] When applied N fertilizer as base fertilizer was the same, plant height, stem diameter, length of major inflorescence, number of effective branch, pod number per plant, seed number per pod, and biomass yield in group with preferred N quantity were significantly higher than those in group with reduced N fertilizer. Rapeseed yield and profits in group with preferred N quantity were signifi- cantly higher than those in group with reduced N fertilizer in field with moderate fertili- ty. In fields with higher fertility, however, the two factors were just a little higher. In group with reduced N fertilizer, use efficiency of N fertilizer, N uptake efficiency, par- tial factor productivity and harvest index of N were all significantly higher than those in group with preferred N fertilizer. Agronomic nitrogen use efficiency in group with preferred N fertilizer was significantly higher than that in group with reduced N fertiliz- er in field with moderate fertility and was significantly lower in field with high yield. With amounts of N, P and K fertilizers fixed, economic characters, yield constitution, yield, profits and N absorption in group, where 60% of N fertilizers were applied as base fertilizer, were significantly higher than those in groups with 80% or 100% of base fertilizer （N fertilizers）. These indicated that rational fertilization would maintain rapeseed yield high and reduce N input to improve use efficiency of N fertilizer. On the other hand, it is effective to improve rapeseed yield.＇to reduce N fertilizer to 150 kg/hm2, and application of 60%. of N fertilizers as base fertilizer is still proved optimal at present. [Conclusion] The research provides.theoretioal and technical references for improvement of yield of rapeseed and efficiency of N fertilizer.

Effect of N Fertilization on Yield, N Absorption and Utilization of Two Species of Super High-Yielding Summer Maize

[Objective] The aim was to study on effects of N fertilizer on yield, N absorption and utilization of different cultivars of super high-yielding summer maize, in order to provide reference for reasonable N fertilization in accordance with different cultivars. [Method] Field experiment was conducted to study on effects of different N fertilizers on yield, N absorption and use efficiency of Zhengdan 958 and Xundan 20, in order to learn the effect differences at different N fertilizer levels. [Result] After N was applied, yields of the two summer maize increased significantly. Zhengdan 958 achieved the highest in yield and proceeds at 12 051.18 kg/hm2 and 1 722.40 yuan/hm2, respectively in low N level. In contrast, Xundan 20 achieved the highest at 13 166.00 kg/hm2 and 1 343.92 yuan/hm2 in the above two aspects in high N level. Compared with Zhengdan 958, Xundan 20 increased by 9.90%, 5.20% and 12.00% in N levels of 0, 240, and 450 kg/hm2, respectively. When N fertilizers were applied, protein yield of Xundan 20 was significantly higher than that of Zhengdan 958, so that higher N fertilizers contributed higher protein yield for Xundan 20. In high N level, N efficiency, N-fertilizer utilization and partial productivity of Xundan 20 were significantly higher than that of Zhengdan 958. [Conclusion] Lower N-fertilizer was suitable for Zhengdan 958 and Xundan 20 would get a good harvest if more N-fertilizers were applied. The results provided references for reasonable N fertilization.

Stability,detonation properties and pyrolysis mechanisms of polynitrotriprismanes C_6H_(6-n)(NO_2)_n (n=1-6)

To further test whether polynitriprismanes are capable of being potential high energy density materials （HEDMs）, extensive theoretical calculations were carried out to investigate on a series of polynitrotriprismanes （PNNPs）： C6H6-.（NO2）. （n=1-6） Heats of formation （HOFs）, strain energies （SE）, and disproportionation energy （DE） were obtained using B3LYP/6-311＋G（2df, 2p）//B3LYP/6-31G＊ method by designing different isodesmic reactions, respectively. Detonation properties of PNNPs were obtained by the well-known KAMLET-JACOBS equations, using the predicted densities （p） obtained by Monte Carlo method and HOFs. It is found that they increase as the number of nitro groups n varies from 1 to 6, and PNNPs with n〉4 have excellent detonation properties The relative stability and the pyrolysis mechanism of PNNPs were evaluated by the calculated bond dissociation energy （BDE）. The comparison of BDE suggests that rupturing the C--C bond is the trigger for thermolysis of PNNPs. The computed BDE for cleavage of C--C bond （88.5 kJ/mol） further demonstrates that only the hexa-nitrotriprismane can be considered to be the target of HEDMs.

Nitrogen Recoveries and Yields Improvement in Cowpea sorghum and Fallow sorghum Rotations in West Africa Savannah

The effects of previous cowpea （Vignaunguiculata） and annual fallow on N recoveries, succeeding sorghum yields and soil properties were studied using a 5-year-old （1995-1999） field experiment at Kouar6 （11°59′ North, 0°19′ West and 850 m altitude） in Burkina Faso. A 3 4 factorial design in a split plot arrangement with three rotation treatments and four fertilizer treatments was used. Total N uptake by succeeding sorghum increased from 26 kg N ha~ in mono cropping of sorghum to 31 and 48 kg N ha~ when sorghum was rotated with fallow or cowpea respectively. Nitrogen derived from fertilizer increased from 10% in mono cropping of sorghum to 22% and 26% when sorghum was rotated with fallow or cowpea respectively. While fallow did not increase N derived from soil, cowpea doubled the quantity of N derived from soil （Ndfs）. Sorghum grain yields increased from 75% and 100% when sorghum was rotated with fallow or cowpea respectively. All rotations treatments decreased soil organic C and N but soil organic C was the highest in fallow-sorghum rotation. It was concluded that cowpea-sorghum rotation was more effective than fallow-sorghum rotation and five management options were suggested to improve traditional system productivity.

Variation in carbon,nitrogen and phosphorus partitioning between above-and belowground biomass along a precipitation gradient at Tibetan Plateau

Precipitation is a potential factor that significantly affects plant nutrient pools by influencing biomass sizes and nutrient concentrations. However, few studies have explicitly dissected carbon(C), nitrogen(N) and phosphorus(P) pools between above- and belowground biomass at the community level along a precipitation gradient. We conducted a transect(approx. 1300 km long) study of Stipa purpurea community in alpine steppe on the Tibet Plateau of China to test the variation of N pool of aboveground biomass/N pool of belowground biomass(AB/BB N) and P pool of aboveground biomass/P pool of belowground biomass(AB/BB P) along a precipitation gradient. The proportion of aboveground biomass decreased significantly from mesic to drier sites. Along the belt transect, the plant N concentration was relatively stable; thus, AB/BB N increased with moisture due to the major influences by above- and belowground biomass allocation. However, P concentration of aboveground biomass decreased significantly with increasing precipitation and AB/BB P did not vary with aridity because of the offset effect of the P concentration and biomass allocation. Precipitation gradients do decouple the N and P pool of a S. purpurea community along a precipitation gradient in alpine steppe. The decreasing of N:P in aboveground biomass in drier regions may indicate much stronger N limitation in more arid area.

Liquid nitrogen level meter for high-temperature superconductor (HTS)

Many kinds of high temperature superconductor （HTS） power machines such as HTS cable, HTS fault current limitcr and HTS magnet are cooled by liquid nitrogen. The level of liquid nitrogen should be monitored and controlled to ensure the thermal stability and the dielectric strength as well. To measure the level, capacitance method and differential pressure method are usually used. However, each method has installation difficulties and measurement errors for unsteady state operation with varying system pressure. A new liquid level meter using a 2G HTS conductor is described, which has similar structure with the liquid helium level meter with NbTi filament. The level meter is fabricated with a parallel connected heater, which helps the separation of the superconducting region and normal region, considering the critical temperature, large heat capacity of conductor and cooling characteristics. The level of liquid nitrogen can be obtained from the measured voltage signal along the 2G HTS conductor. Design, fabrication and test results of the new liquid nitrogen level meter are presented.

The Effects of Manure, Lime and P Fertilizer on N Uptake and Yields of Soybean （Glycine max （L.） Merrill） in the Central Highlands of Kenya

Soybean （Glycine max （L.）） is one of the most important legume crops being introduced in the CHK （Central Highlands of Kenya） expected to increase yields. However, low levels of soil N （nitrogen） and other plant nutrients and soil acidity are seen as the major causes impairing goal achievement. To evaluate the influence of manure, lime, P （phosphorus） fertilizer and their combination on N uptake and soybean performance, an experiment was conducted in Embu ATC （Agricultural Training College） comprising 9 treatments, arranged in a Randomized Complete Block Design with 4 replicates in plots of 4 m×4.5 m. The study included manure （0, 5 and 10 t-ha-1）, lime （0 and 2 t.ha-1） and P fertilizer （0, 30 and 60 kg.P.hal）. The treatments significantly influenced N uptake and soybean yields. Both parameters responded well to application of manure both alone or combined to lime and TSP （triple super phosphate）. From these it was concluded that organic and inorganic resources have potential to enhance N uptake and soybean and other crops yields in CHK.

Stability and Electronic Properties of Metal-N4 and Metal-N2 Complexes

Nitrogen molecules Nx have been the subject of much recent research because of their potential as high-energy materials. Many nitrogen molecules dissociate with very low barriers, including molecules such as acyclic N4 that are essentially unbound. A number of studies have reported the ability of heteroatoms to stabilize complex nitrogen molecules. In the present study, the energetic and electronic properties of scandium（Ⅰ） and titanium（Ⅱ） complexes with N2 and N4 are calculated and discussed. Dissociation energies and singlet-triplet energies are determined by theoretical calculations using second-order perturbation theory （MP2） in conjunction with the Dunning basis sets.

Magnitude and Trends of High-elevation Cloud Water Pollutant Concentrations and Modeled Deposition Fluxes

Cloud water samples, LWC （Liquid Water Content） and meteorological data were collected at the Clingmans Dome, Tennessee, high-elevation site in Great Smoky Mountains National Park during the warm season from 1994 through 2011. This paper presents results from 2000 through the conclusion of the study in 2011. Samples were analyzed for SO42＂, NO3, NH4＋ and H＋. These measurements were supplemented by measurements of ambient air and precipitation concentrations to estimate dry and wet deposition. Cloud water concentrations, LWC, cloud frequency, various meteorological measurements and information on nearby forest canopy were used to model cloud water deposition to gauge trends in deposition. Total deposition was calculated as the sum of cloud, dry and wet deposition estimates. Concentrations and deposition fluxes declined over the study period. The decreases in cloud water SO42＂ and NO3 concentrations were 40 percent and 26 percent, respectively. Three-year mean 5042 and NO3 deposition rates decreased by 71 percent and 70 percent, respectively. Trends in concentrations and depositions were comparable with trends in SO2 and NOx emissions from Tennessee Valley Authority power plants and aggregated emission reductions from electric generating units in adjacent states. Back trajectories were simulated with the HYSPLIT model and aggregated over cloud sampling periods from 2000 through 2007 and 2009 through 2011. Trajectories during periods with high H＋ concentrations traveled over local EGU （Electric Generating Unit） emission sources in Tennessee and Kentucky to the Ohio River Valley, Alabama and Georgia with the conclusion that these source regions contributed to acidic cloud water deposition at Clingmans Dome. This work was supported by U.S. Environmental Protection Agency and the Tennessee Valley Authority with infrastructure support provided by the National Park Service.

Influence of dietary Lys levels and dietary net energy levels on growth performance and nitrogen balance of growing pigs

Two experiments were conducted to determine the effects of L y s ine（Lys） and Net Energy （NE） levels on growth performance （Exp. I） and N balance （Exp. 2） in growing pig. In Exp. 1, 36 castrated pigs [21.35 -4- 0.55 kg of body weight （BW）] were allotted to six treatments with six replicates per treatment. Pigs were fed two levels of Lys （low and high） and three levels of NE （low, med, or high） in a 2×3 factorial arrangement. The experiment lasted for 35 d. There were no effects of dietary Lys and NE on pig performance （P〉0.05, but a Lys×NE interaction in ADG was observed （P〈0.05）. In Exp. 2, 24 pigs were used to determine the effects of diet in Exp. 1 on pig N balance. Neither Lys nor NE level affected N retention （g/d） （P〉0.0）. Lys×NE interaction in N retention （g/d） （P〈0.01） and in N apparent biological value （ABV） （P〈0.05） was observed. Pigs fed the low Lys diet had lower serum urea nitrogen （SUN） concentrations compared with the high Lys treatment （P〈0.01）. Pigs fed the med-NE diet had lower SUN concentrations compared with the pigs fed the low-NE diet （P〈0.1）. These results suggest that pigs from 21 kg to 50 kg BW fed diets containing 0.83% standardized ileal digestible Lysine and 2351 Kcal of NE/kg had maximum ADG and N retention.

不锈钢概论（28）

（4）高氮铬锰奥氏体不锈钢 大量事实已证实，向奥氏体不锈钢中加入高氮量所获得的高氮奥氏体不锈钢，其固溶态屈服强度可达1100MPa，远超过奥氏体沉淀硬化不锈钢时效后的水平，若再经冷加工，则可高达3000MPa以上（图5．32），

Nitrogen-doped black titania for high performance supercapacitors

For energy storage system,it is still a huge challenge to achieve high energy density and high power density simultaneously.One potential solution is to fabricate electrochemical capacitors(ECs),which store electric energy through surface ion adsorption or redox reactions.Here we report a new electrode material,heavy nitrogen-doped(9.29 at.%)black titania(TiO2-x:N).This unique hybrid material,consisting of conductive amorphous shells supported on nanocrystalline cores,has rapid N-mediated redox reaction(TiO2-xNy+zH++ze■-TiO2-xNyHz),especially in acidic solutions,providing a specific capacitance of 750 Fg-1at 2 m V s-1(707 Fg-1at 1 A g-1),great rate capability(503 F g-1at 20 Ag-1),and maintain stable after initial fading.Being a new developed supercapacitor material,nitrogen-doped black titania may revive the oxide-based supercapacitors.

Effect of Combined Use of Brackish Water and Nitrogen Fertilizer on Biomass and Sugar Yield of Sweet Sorghum

Soil salinization and non-point source pollution are among the most important and widespread environmental problems in European Mediterranean regions. Sweet sorghum （Sorghum bicolor （L.） Moench var. saccharatum） is a moderate to high salinity tolerant crop with low water and nutrient needs, seen as an alternative to grow in the water scarce regions. A three-year multifactorial study was conducted in southern Portugal to evaluate the combined effects of saline water and nitrogen application on the dry biomass （total, stems, and leaves）, sugar content （total reducing sugars and sucrose eontents） and sugar yield （here defined as the product of total reducing sugars and stems dry biomass） functions of sweet sorghum. Sorghum dry biomass and sugar yield showed diminishing returns for each incremental change of nitrogen. The use of saline irrigation waters also led to yield reduction. Exception was sucrose content which increased with increasing levels of sodium in the soil. Nitrogen need decreased as the amount of sodium applied increased. Stem dry biomass, sucrose content, and sugar yield progressively increased with progress in the experiment. The effect could be attributed to the increase of the amount of irrigation applied throughout the years, thus increasing the leaching fraction which promoted salt leaching from the root zone, reduced the salinity stress, increased plant transpiration, nitrogen uptake and biomass yield.

Leaf Longevity in a Timberline Tree Species Juniperus saltuaria in the Sergymla Mountains,Southeastern Tibet

Leaf longevity is an important adaptive strategy that allows plants to maximize photosynthetic carbon gain.Due to the difficulty of identifying overwintering bud scars and distinguishing the age sequence of twigs,leaf longevity is rarely studied in Cupressaceae species,which further limits our understanding of the leaf economic spectrum (LES) for these populations.Here,we investigated the leaf longevity,as well as mass-based leaf nitrogen concentration (N;),of Juniperus saltuaria at different canopy heights for both subalpine and alpine timberline forests in the Sergymla Mountains,southeastern Tibet.We found that the mean leaf longevity was 4.2±1.2 years,and overall it did not differ significantly between different elevations.Along the vertical profiles of juniper canopies,the leaf longevity did not reflect a linear trend.With increasing leaf longevity,N;showed declining trends.We further analyzed the relationship between leaf longevity and the corresponding length of green twigs,and found that the length of green twigs could only explain 1%-3%of the variation in leaf longevity,indicating that the length of green twigs is a poor predictor for the variation in leaf longevity.In summary,for the J.saltuaria species in timberline or nearby subalpine forests,the effects of elevation and canopy depths on leaf longevity are minor,and the leaf trait analysis is in accordance with the prediction of LES.