钒氮微合金化技术中氮收得率影响因素分析

从钢液氧化性、脱氧合金化顺序、合金加入时间与下渣量、合金添加方式、合金种类、钢液钒含量、钢液终点温度等方面,对钒氮微合金化技术中氮收得率的影响进行分析,为钒氮微合金化钢中氮的稳定控制提供参考,以提高钒氮微合金化效果。

提高GX12CrMoWVNbN10-1-1钢中氮收得率的实践

针对生产GX12CrMoWVNbN10-1-1钢时氮收得率低的情况,对氮的合金化工艺进行优化。3种充氮合金化工艺的对比结果表明:真空前加氮化铬合金,真空时用氮气代替氩气的氮合金化工艺效果最好,能在不影响产品质量的情况下使氮化铬中氮收得率从15.40%提高到25.43%。

稻田生态系统氮素转化经济价值研究

根据2002年上海奉贤县五四农场田间实验数据,结合相关研究结果对稻田氮素输入和输出进行研究,并运用生态经济学和环境经济学方法计算稻田生态系统氮素转化的经济价值.结果表明,当季不施氮肥的处理小区氮素收支出现赤字;而施加氮肥的处理小区氮素收支都出现盈余.不施氮处理小区单位面积稻田提供的氮素转化综合价值为正;而施加氮肥的小区其氮素转化的综合价值都为负.施氮处理小区氮素转化的负价值主要是由于过量氮肥导致田间氮素以氨挥发、渗漏和径流方式损失造成.

真空感应炉冶炼含氮316L不锈钢的控氮工艺研究

通过试验研究了氮分压与316L不锈钢中氮溶解度的关系,研究表明钢中氮的溶解度随着氮分压的增大而增大.500 kg真空感应炉内冶炼含氮316L奥氏体不锈钢（N：0.1％～0.2％）,在充氮至（0.2～0.8）＆#215;105 Pa时加入FeCrN（Cr：60％,N：6％）.结果表明,在氮气保护环境中加入FeCrN,在充氮至（0.2～0.3）＆#215;l05 Pa时氮的收得率为65％～80％;在充氮至（0.5～0.6）＆#215;105 Pa时氮的收得率为80％～90％;进一步提升炉内氮气压力至0.8＆#215;105Pa,控制合适的钢液温度,氮的收得率可达100％.

45t LF(VD)精炼钒氮非调质钢的增氮工艺

试验和分析了成分为(%):0.42C、0.62Si、1.42Mn、0.11V、0.015N钒氮非调质钢LF(VD)吹氮精炼时合金元素、LF和VD工艺参数对该钢增氮的影响。结果表明,前期加固氮合金元素V、Cr、Mn,快速提高LF精炼温度至1620～1630℃,增加精炼吹氮时间,可使平均增氮速率达2.83×10^(-6)/min;VD处理进行氮气搅拌,控制VD处理时间,可提高氮的收得率。

钴铬钼医用合金增氮工艺

铸造钴铬钼合金使用氮化铬合金增氮,加入前冲入氮气、氩气混合气能够抑制合金液面快速上升,防止沸腾喷溅。结果表明,氮的收得率在87%~92%之间,氮含量与氧含量增加呈降低趋势,增氮的钴铬钼医用合金的抗拉强度、延伸强度、断后生产力分别高出国标30%、80%和20%以上。

缢蛏肉的蛋白酶水解工艺研究

实验研究了用枯草杆菌中性蛋白酶水解缢蛏肉的工艺条件,通过单因素试验和正交实验,得出了最适水解工艺条件为加酶量2.4％,水解温度50℃.料水比1:3。pH值为中性,时间为6h.水解产物的水解率和总的氮收率分别为42.46％和83.04％。水解液经脱腥等处理后可用于复合调味料和营养口服液的生产。

单环刺螠体壁肌酶解工艺参数的研究--动物蛋白水解酶

烟台海肠即单环刺螠,为国家地理标志农产品,以其体壁肌为原料进行酶解工艺参数研究。采用动物蛋白水解酶进行酶解,研究发现酶的添加量、pH、酶解时间、酶解温度对氮收率和水解度均具有极显著影响,此酶的适宜添加量为2%,pH为7.0,酶解时间为4h,酶解温度为50℃。在此适宜条件下,单环刺螠体壁肌的氮收率和水解度分别达到94.45%和48.17%,体壁肌中的蛋白质几乎被完全水解到水解液中。

罗非鱼内脏蛋白酶特性及内脏蛋白自溶工艺研究

以罗非鱼内脏为原料,研究内源蛋白酶酶学特性;利用正交试验对其自溶工艺进行优化,结果表明:罗非鱼内脏内源蛋白酶在pH 5～11范围内有较好的稳定性,在40～50℃条件下,罗非鱼内脏蛋白酶活性最稳定;罗非鱼内脏自溶的最佳工艺为:pH 8,温度45℃,料液比1:2条件下的自溶4 h产物氮收率为73.21%,水解度为18.78%。

单环刺螠体壁肌酶解工艺参数的研究——复合风味蛋白酶

采用复合风味蛋白酶水解单环刺螠体壁肌,为体壁肌水解肽的酶法脱苦提供酶解工艺参数。研究发现:酶的添加量、pH、酶解时间、酶解温度对氮收率和水解度均具有极显著影响,此酶的适宜添加量为170LAPU/kg原料,pH为6.5,酶解时间为1.5h,酶解温度为55℃,在此适宜条件下,单环刺螠体壁肌的氮收率和水解度分别达到70.71%和35.09%,水解液澄清,无苦味,复合风味蛋白酶可以用于单环刺螠体壁肌水解肽的脱苦。

响应面优化酶解马骨粉工艺的研究

利用碱性蛋白酶水解马骨粉,得到营养马骨多肽粉。以氮收率和水解度为指标对骨粉进行单因素实验。在单因素基础上运用Design Expert8.0Trial统计软件,以水解度为响应值,得到最佳酶解条件为:酶解温度47℃,料液比1∶7g/mL,酶解pH9,加酶量6200U/g,此时最高水解度为17.47%。结果表明,酶解可以显著提高马骨粉中蛋白质的水解度。

单环刺螠体壁肌酶解工艺参数的研究

采用木瓜蛋白酶水解单环刺螠体壁肌,为体壁肌水解肽的酶法脱苦提供酶解工艺参数。研究发现,酶的添加量、pH值、酶解时间、酶解温度对氮收率和水解度均具有极显著影响,此酶的适宜添加量为3%,pH值为7.0、酶解时间为5h,酶解温度为50℃,在此条件下,单环刺螠体壁肌的氮收率和水解度分别达到69.62%和32.90%,水解液呈淡棕色。

2种蛋白酶分步水解鲢鱼肉蛋白工艺及性质研究

以鲢鱼肉为原料,利用酶解位点和反应条件不同的碱性蛋白和风味蛋白酶对其进行水解,检测对水解度影响,用正交试验优化水解工艺。在2种酶的最适水解参数下,采用2种酶相结合的分步酶解方式:鱼肉∶水=1∶4将鱼蛋白打浆,先加入1 800 U/g(protein)的碱性蛋白,于起始p H值8.0、55℃下水解2 h,再加入1 800 U/g(protein)的风味蛋白酶继续水解2 h,其水解度达到35.05%,较碱性蛋白酶或复合蛋白酶单独使用有显著提升。通过本试验,水解度对酶解产物的溶解性、乳化性、起泡性能、泡沫稳定性、粘度等性质都有较大影响。

超声辅助酶解制备草鱼鳞胶原肽及其理化特性评价

以草鱼鳞为原料,基于研究室原有工艺条件,在酶解过程中施加超声,研究超声功率(0∼600 W)和超声时间(0∼40 min)对胶原肽得率及理化特性的影响。结果表明,超声对产物得率影响显著。单酶酶解使用碱性蛋白酶、复合蛋白酶、中性蛋白酶。超声条件增加,水解度和氮收率先升高后降低;在碱性蛋白酶酶解时施加300 W、20 min超声,水解度从5.37%升到7.27%;分步酶解使用碱性蛋白酶和风味酶,在每步酶解各施加300 W、10 min超声时,水解度从9.26%升到11.05%。超声对产物分子量和氨基酸含量有一定影响,产物分子量集中在500 u~1 ku,单酶酶解胶原肽在该段分布从24.26%升至33.99%,分步酶解胶原肽在该段分布从31.99%升至39.28%;单酶酶解氨基酸含量从66.30 g/100 g升至73.75 g/100 g;分步酶解从66.05 g/100 g升至70.70 g/100 g。超声对产物乳化性、起泡性和泡沫稳定性影响显著。综上,单酶酶解最佳工艺为碱性蛋白酶酶解中施加300 W、20 min超声;分步酶解最佳工艺为在每步酶解中各施加功率300 W、时间10 min的超声。

Variation of Nitrogen Uptake and Utilization Efficiency of Mid-Season Hybrid Rice at Different Ecological Sites under Different Nitrogen Application Levels

[Objective] The study aimed at investigating the effects of different geographic sites,soil chemical characteristics and nitrogen application levels on nitrogen accumulation and distribution in different organs and utilization efficiency for mid-season hybrid rice.[Method] By using mid-season rice varieties II-you 7 and Yuxiangyou203 as the experimental materials,field experiment was conducted at seven ecological sites in four provinces or cities in Southwestern China in 2009.A total of four nitrogen application levels were set as follows：by using 75 kg/hm2 of P2O5 and 75 kg/hm2 of K2O as the base fertilizer,extra 0,90,150 and 210 kg/hm2 of nitrogen fertilizer（in which,base fertilizer,base-tillering fertilizer and base-earing fertilizer respectively accounted for 60%,20% and 20%.） was applied,respectively.In the split-plot design,fertilizer was considered as the main factor while rice variety was taken as the secondary factor.A total of eight treatments were set with three replications.[Result] Highly significant differences of grain yield were found among seven locations,two varieties,four nitrogen application levels,interactions of site × variety and site × nitrogen application level,but the interaction of variety ×nitrogen application level had no significant influence on rice yield.There were highly significant effects of site,varieties and nitrogen application level on dry matter production,nitrogen content,nitrogen utilization efficiency.Highly significant negative correlations between uptake efficiency and utilization efficiency for nitrogen were found;and multiple stepwise regression analysis showed that nitrogen uptake-utilization efficiency were significantly influenced by different ecological sites,chemical quality of soil and the levels of nitrogen application.[Conclusion] The research will provide theoretical and practical basis for the highly efficient application of nitrogen in mid-season hybrid rice cultivation.

Effects of Green Manure Rotation on Rice Growth Dynamics and Nitrogen Uptake and Utilization

This study aimed to comprehensive evaluation of different winter green manure on characterization of nitrogen uptake and utilization, to provide the basis for N fertilizer reasonable operation and characteristics improvement of nitrogen nutrition in rice high-yield cultivation. This experiment was set to compare milk vetch, rapeseed,ryegrass and mixed of green manure on rice yield, rice growth dynamics and nitrogen uptake and utilization in rice. The results showed that among 4 different winter green manure, the treatment of MV-R-R（milk vetch-rice-rice） for the early rice yield was the most than others treatments. Compared with RG-R-R（ryegrass-rice-rice）, RPR-R（rapeseed-rice-rice）, MS-R-R（mixed green manure-rice-rice）, the treatment of MVR-R inceased by 6.61%, 3.29%, 0.78%, respectively. The treatment of MV-R-R in N content in plant of rice was maximized in the tillering, booting, heading and maturity periods, respectively higher than the average of other treatments 9.68%, 19.72%,6.23% and 8.66%. At tillering, booting, heading and maturity, the treatment of MV-R-R were the highest in N uptake, RP-R-R minimum. The N periodic accumulation for MV-R-R were higher than other treatments in the tillering to booting, booting to heading and heading to maturity periods. The rates respectively were 21.81%, 68.73% and286.5%. In addition, N periodic accumulation and its ratio to total in the heading to maturity was minimum, maximum before tillering under green manure rotation system.So the cropping system of milk vetch-rice-rice could increase nitrogen use efficiency and improve N cycling.

Effect of Transplanting Density on Rice Yield,Nitrogen Uptake and ^(15)N-fertilizer Fate

[Objective] The aim of this study was investigated the rice yield, nitrogen uptake and ^15-fertilizer fate at different transplanting density to provide scientific ba- sis for improving the yield of rice and applying reasonably fertilizer. [Method] A field experiment was carried out to study the effect of different transplanting density on rice yield, nitrogen （N） absorption, sources of N uptake by rice and the N balance in the plant-soil systems by using ^15-labelled urea. [Result] There were no significant differences in rice yields and total N uptakes by rice between treatments 30 cm × 30 cm and 40 cm × 40 cm, but the yield of rice and total N absorption in the two treatments were remarkably higher than those in 50 cm × 50 cm treatment. The amounts of total N uptake by rice were in the range of 112.3-162.7 kg/hm2 in the three transplanting densities. The result showed that about 1/3 of the total N uptake by rice was supplied by application fertilizer and the other 2/3 was obtained from the soil N pool. The ^15N-labelled urea absorbed by rice, residual in soil and lost accounted for 16.3%-26.1%, 17.0%-20.9% and 53.0%-66.7% of the total fertilizer, respectively. A great deal of ^15N-labelled urea was lost during the rice growing season. [Conclusion] Considering the rice yield and environmental protection, the transplanting density of 30 cm×30 cm was recommended in the hilly area of Sichuan basin in the southwest China.

Effects of Nitrogen Fertilization on the Growth and N Uptake of Late-sowing Winter Oilseed Rape (Brassica napus L.)

[Objective] The aim of this work was to analyze the N fertilization on the vegetative growth and N uptake of different winter rapeseed varieties at wintering stage. [Method] In two consecutive years （2009-2011）, two winter rapeseed varieties （B. napus L.）, an early maturity variety Zhongyou 116 （ZY116） and a middle-late application maturity variety Zhongyouza 12 （ZYZ12） were employed. Field experiments with different N levels （0, 90, 180, 270, 360 kg N/hm 2 ） were designed. At the wintering stage, the dry matter weight, the nitrogen content and concentration of plants, leaf nitrate reductase activity （NRA） and seed yields were investigated. [Result] The shoot dry matter of ZY116 increased rapidly when N rate ranged from 0 to 180 kg/hm 2 , and it raised slightly when N rate ranged from 180 to 360 kg/hm 2 . The shoot dry matter of ZYZ12 were changed in a single peak curve; the peak of shoot dry matter appeared at 270 kg N/hm 2 . The N concentration and N content in shoot and root increased rapidly when the N rate changed from 90 to 180 kg/hm 2 . Moreover, the N concentration and N content root of in ZYZ12 were much higher than that of ZY116. Present study revealed that the changed trend of leaf nitrate reductase activities （NRA） were significantly increased at the N rate of 180 kg/hm 2 in ZY116 and ZYZ12 compared with the N rate of 90 kg/hm 2 in two years. [Conclusion] Optimal nitrogen application significantly increased the dry weights and N uptake at wintering stage as well as increasing the yield of winter oilseed rape.

Effects of Slow-release Fertilizer and Balanced Fertilization on Nitrogen, Phosphorus and Potassium Uptake in Peppers

Field plot experiment was conducted to study the effects of two slow-re- lease fertilizers and balanced fertilization on dry matter accumulation, yield, fertilizer use efficiency, nitrogen, phosphorus and potassium uptake of peppers at Jiangna Town, Yanshan County, Yunnan Province in 2011. The results showed that the dry matter accumulation in dried pepper plant, pepper yield, nitrogen, phosphorus, potassium uptake in peppers were significantly increased in all the fertilizer treat- ments, compared with those in control （no fertilizer）. Compared with conventional fertilization, balanced fertilization, slow-release compound fertilizer and slow-release urea fertilizer significantly increased dried pepper economic output by 20.94%, 17.5% and 14.54%, nitrogen uptake in dried peppers by 21.53%,18.46% and 13.19%, phosphorus uptake in dried peppers by 14.08%, 15.76% and 10.44%, potassium uptake in dried peppers by 22.66%, 15.73% and 16.28%; they also in- creased nitrogen and potassium use efficiency, but reduced potassium use efficiency due to the increased potassium addition. In treatments with balanced fertilization, slow-release compound fertilizer and slow-release urea fertilizer, the nitrogen utiliza- tion was 5.84%, 7.14% and 8.33% higher and the phosphorus utilization was 3.32%, 3.27% and 2.47% higher than those in treatment with conventional fertiliza- tion. In addition, the nitrogen application could be reduced by 20%-50% by bal- anced fertilization and the two slow-release fertilizers, thereby reducing environmen- tal pollution. Slow-release fertilizers could also reduce the frequency of fertilization and labor costs.

Cloning of Glutamate Dehydrogenase cDNA from Chlorella sorokiniana and Analysis of Transgenic Tobacco Plants

A full_length cDNA has been cloned encoding nicotinamide adenine dinucleotide phosphate_specific glutamate dehydrogenase (NADP_GDH) from Chlorella sorokiniana with the RT_PCR method. The complete nucleotide sequence of NADP_GDH gene had 94% homology to the previously reported one . The NADP_GDH gene was constructed into a vector highly expressed in plants. The specific activity of NADP_GDH in transformants was detected, but not in the control plants. All transformed shoots on MS medium containing lower concentration of nitrogen and the transformed seedlings grown in lower concentration of nitrogen vermiculite had higher growth rate and more leaves than the control plants. Transformed leaf discs cultured on MS medium containing different nitrogen concentrations had more chlorophyll contents compared to the controls. These results suggested that exogenous NADP_GDH may enhance the absorption and utilization to ammonium in plants. The increased weight of transformed leaf discs cultured on medium supplemented with different concentrations of phosphinothricin (PPT) was more than that of control discs. 0.5 μg/mL PPT could be used as a selecting drug instead of kanamycin to develop the transformants. These results suggested that the NADP_GDH gene might be used as a new selecting gene in the future research of plant gene engineering.