不同氧化数的钒氧化物及FCC催化剂上沉积钒的程序升温还原表征

选用能对沉积钒和沉积镍的氧化数进行定量表征的程序升温还原（TPR）测试方法，考察了催化裂化催化剂上沉积金属氧化数对降低汽油硫含量的影响。结果表明．V2O3、V2O2、V2O5的最终还原产物是VO，催化剂上沉积钒与纯的钒氧化物出现TPR特征峰的温度范围相似；纯NiO易于被还原，而催化剂上沉积镍的TPR特征峰温度明显升高。择效活化处理导致催化剂上的沉积钒氧化数降低。在623～923K范围内，沉积钒的氧化数随着择效活化温度的增加而降低；923K时氧化数接近2。基本达到热力学平衡。沉积钒氧化数的降低改变了沉积钒的化学配位效应。有利于形成选择性降低汽油硫含量的活性中心，因而使得催化裂化汽油硫含量下降。当沉积钒的表观氧化数低于3时，催化剂的降硫效果大大提高。     

Effects of feeding micronised flaxseed on yield and composition of milk from Holstein cows

Nine multiparous Holstein cows were used in three 3 × 3 Latin squares to investigate the effects of feeding unheated and micronised flaxseed on milk yield and milk fatty acid composition. Three diets were formulated to meet the nutrient requirement of dairy cows in early lactation: a control diet with no added flaxseed (NFS), an unheated flaxseed diet (UFS) and a micronised flaxseed diet (MFS). The level of flaxseed in UFS and MFS was 70 g kg^?1 of the diet dry matter (DM). Feeding flaxseed to dairy cows had no effect on DM intake or milk yield. However, energy‐corrected milk was higher (P < 0.05) for cows fed MFS than for those fed UFS or NFS. Supplemental flaxseed reduced (P < 0.05) the milk fat percentage without affecting the concentration of milk protein or milk lactose. However, the yield of milk components was not affected by feeding flaxseed. The concentrations of short‐chain (C_4:0 to C_12:0) and medium‐chain (C_14:0 to C_17:0) fatty acids were decreased (P < 0.05) while those of long‐chain fatty acids (C_18:0 to C_18:3) were increased (P < 0.05) in the milk of cows fed UFS and MFS compared with cows fed NSF. Feeding flaxseed to dairy cows can alter the milk fatty acid composition, but only minor effects on milk fatty acid composition can be expected by feeding micronised versus unheated flaxseed. Copyright © 2003 Society of Chemical Industry     

四川盆地北部元坝地区雷四上亚段埋藏成岩作用分析

以显微薄片观察为基础,结合扫描电镜、电子探针、薄片能谱、元素kσ面分布以及阴极发光等分析手段对四川盆地北部雷四上亚段古风化壳储层主要埋藏成岩作用的类型、特征、成因及对储层的影响进行了研究和探讨。本区雷四上亚段风化壳储层经历的埋藏成岩作用类型主要有压实压溶作用、破裂作用、胶结作用、埋藏溶蚀作用、自生矿物的形成等。通过对裂缝内充填胶结矿物的分析研究,认为矿物胶结期次有两期:第一期为碱性热液形成碳酸盐岩矿物(铁白云石、铁方解石);第二期为富含F-、Si4+、Sr-等离子的酸性热液形成石英、萤石、天青石等热液矿物。溶蚀作用有四期,依次为:第一期酸性热液-第二期碱性热液-第三期酸性热液-第四期碱性热液溶蚀。溶蚀作用形成的脉内晶间孔、脉内晶间溶孔以及溶蚀缝占埋藏次生孔隙的主导地位。     

绥靖油田大路沟二区重复压裂技术研究与试验

重复压裂技术作为大路沟二区油井提高单井产量的主要进攻性措施, 历年效果不明显。为了提高该区块重复压裂效果, 文章从储层地质特征、 开发现状等方面分析, 认为储层物性差、 非均质性强、 渗流阻力大等方面是影响大路沟二区油井低产低效的主要因素。针对该区域储层微裂缝发育的现状, 提出了多裂缝压裂工艺技术,即借助于砂比、 排量等施工参数的多次反复调整和暂堵剂段塞的运用, 造成施工压力波动, 使主裂缝壁面存在的多个微裂缝能随压力波动出现反复开启 －有限延伸 －闭合的状态, 最终形成压裂主裂缝和多个缝长较短的支裂缝,达到有效增加压裂总缝长、 降低储层流体渗流阻力, 提高单井产量的技术目的。通过室内工艺优化和１ ４口井的现场试验表明, 该技术与常规重复压裂相比, 增产效果显著提高, 为该区块提高重复压裂效果进行了有力探索。     

准噶尔盆地滴南凸起一五彩湾地区天然气成因与成藏过程分析

一般认为天然气具有晚期成藏的特征,但通过对准噶尔盆地滴南凸起一五彩湾地区石炭系天然气成藏的研究则得到了不同的认识。研究区的天然气以湿气为主,干燥系数均值为0．92,非烃气体中N2含量均值为3．04％;而天然气的δ^13C1均值为-32．12‰,明显偏高,反映出天然气成熟度已经处于干气阶段。通过对研究区天然气成因与成藏分析,认为该地区具有“早期聚集、晚期保存”的天然气成藏过程,总体来说该地区经历了海西晚期、印支晚期和燕山中期的多期油气充注和成藏,但燕山中期是该地区成藏的关键时期,并且该时期主要聚集的是石炭系烃源岩在．Ro值达到0．8％～1．2％之后生成的天然气,这也是造成该地区天然气组分碳同位素值偏高的主要原因。     

新疆油田超稠油开发地面集输注汽工艺技术

超稠油由于其黏度高,开采技术难度大,一直难以实现经济开采。新疆油田通过试验研究,提出了多项优化、简化地面集输工艺的配套技术,运用了多通阀选井工艺、短半径注汽方式、称重式计量技术、计量接转注汽一体化建站模式等,使工人劳动强度有所降低,地面建设工程量和管理点减少,与常规计量站建设相比,节约投资约25%,稠油地面集输工艺水平有了较大提高。     

稀土离子与NaY分子筛的滤饼柱交换过程

研究了稀土离子与NaY分子筛滤饼柱的交换过程。结果表明，与间歇交换相比，采用分子筛滤饼柱进行稀土离子交换，可以在较短时间内得到较高的稀土离子交换度。调整稀土离子和NH4^ 在交换液中的比例，可以在滤饼柱上获得具有一定稀土离子交换度且稀土分布均匀的Y型分子筛产品。交换液温度对稀土与NH4^ 混合交换的稀土交换度影响较大，但可以通过调整稀土离子与NH4^ 在交换液中的比例弥补交换度的差异。用约3倍于分子筛量的去离子水以洗去分子筛上残余的Na^ 、稀土离子和Cl^-。     

CHARACTERIZATION OF STOMACH AND PYLORIC CAECA PROTEINASES OF TAMBAQUI (COLOSSOMA MACROPOMUM)

The effects of pH, temperature, inhibitors, and substrates on proteolytic activities of crude extracts from the stomach, liver, pyloric caeca, and intestines of Colossoma macropomum were investigated. The highest acid and alkaline proteolytic activities were found in stomach and pyloric caeca, respectively. The optimum pH for the acid and alkaline proteases were 1.8 and 7.0–9.0, respectively, while the optimum temperatures were 35C and 65C. This alkaline protease thermal stability remained unaltered after 90 min incubation at 55C. A pepsin‐like protease was responsible for most of the acidic proteolytic activity (Pepstatin A inhibited approximately 90%), whereas PMSF inhibited about 40% of the alkaline protease. The alkaline proteolytic activity has attractive thermal properties for industrial applications.     

基于RSSI的无线传感器网络距离修正定位算法

节点自身定位是无线传感器网络目标定位的基础。无线传感器网络节点定位算法包括基于距离和距离无关两类。其中基于RSSI的定位算法由于实现简单而被广泛使用,但RSSI方法的测距误差较大,从而影响了节点定位精度。提出了一种基于RSSI的无线传感器网络距离修正定位算法。该算法通过RSSI测距,计算近似质心的位置,以此为参考点进行距离修正,然后确定节点的位置。仿真结果表明该算法可以提高节点定位精度。     

Iron status and diet in athletes

Plasma ferritin (F) concentrations were measured (range 12-245 ng.ml-1) as an indicator of iron status in 24 male and 45 female healthy, nonanemic athletes. Usual food intake was assessed using a self-completed but supervised food frequency questionnaire. Linear regression was applied to determine the relationship between log F (as data was skewed) and average daily intake of iron (Fe), meat (M), protein (Pr), carbohydrate (CHO), fat (Fa), fiber (Fi), and kilojoules (Kj). There were negative correlations between F and each of Kj (P < 0.01) and CHO (P < 0.001), and a positive correlation between F and Pr/Kj (P < 0.01). No significant relationship existed between F and any of Fe, M, Fa, or Fi. These data suggest that iron or meat intake may not be important determinants of iron status in these athletes. Instead, the percentage of protein in the diet may be more influential on F, as may the (negative) effect of Kj and CHO intake, or at least their reflection of energy expenditure.