雷达液位计在物位测量中的应用

简述了雷达液位计的工作原理,重点介绍在一些特殊工况中的应用,体现了雷达液位计在测量某些特殊物位时的优点.     

油罐物位用雷达液位计的分析

雷达液位计又称微波液位计(Radar),其朝一个目标发射电磁波,电磁波发射后遇到反射返回发射源。安装在发射源处的接收器捕获到反射波,并把它与发射波作比较,确定目标的存在和它到发射源的距离。     

UHC系列高压磁浮子翻板液位计在我公司的应用

过去我公司氨洗涤塔液位测量使用的是电动 型浮筒液位计 ,由于现场设备震动大 ,该表抗震性能差 ,经常引起测量失准 ;再者由于无就地液位指示 ,液位计的现场调校完全凭经验 ,下限对零位 ,上限对满度 ,给化工操作人员和仪表维护人员带来许多不便 ,威胁到人身和设备安全 ,影响了生产安全长周期运行。为解决上述问题 ,经考察研究决定选用既具有就地液位指示又具有远传功能的高压磁浮子翻板液位计。经综合比较 ,最后选用了苏州化工仪表厂研制生产的 UHC高压电远传磁性浮子翻板液位计。1　磁浮子液位计的结构及工作原理1 .1　仪表结构UHC高压磁…     

γ射线液位计在我厂的应用

一、概述高压容器的液位测量,在化工行业中一直是较难解决的问题。我厂原先在铜塔、氨分离器、氨冷凝塔上先后使用过高压气动浮筒液位计、电容式液位计、差压式液位计等,但由于被测量液体的结晶或液体中所带的油污使液位测量不准确,甚至失灵而导致     

射频导纳液位计的应用探讨

尿素界区中压分解器L102液位的测量由电容式液位计改为射频导纳液位计,克服了原电容式液位计的缺点,技术比较先进,可靠性与准确性高,故障率低,维护量小。     

电极式液位计的制造

在电镀生产和污水处理中,需要对液位监控,以达到自动控制的目的。常用的液位计有浮简(浮球)式和电极式两种。前者结构复杂、价格较贵,适用于电导很小的液体。后者结构简单、价格低廉,适用于电导较大的液体。我厂自制了一批电极式液位计,使用效果颇佳。     

雷达液位计的故障判断处理

文章对雷达液位计的组成及工作原理和标定进行了介绍,对雷达液位计安装要求及注意事项进行了说明,最后阐述了雷达液位计的故障判断处理。     

罗斯蒙特SAAB雷达液位计天线选型

罗斯蒙特SAAB雷达液位计由于有着较高的测量精度和良好的可靠性,被用于储罐液位的测量工作。雷达天线种类较多,适用的储罐广泛,本文主要分析罗斯蒙特SAAB雷达液位计三种雷达天线的优劣,为雷达天线选型和提高雷达液位计平稳运行效率提供参考。     

雷达液位计在尿素装置的应用

中石油乌鲁木齐石化分公司一化肥尿素装置汽提塔在国内首次采用雷达液位计,介绍雷达液位计与传统放射液位计的不同,液位计的工作原理、特点及安装注意事项,对应用前景进行展望。     

导波雷达液位计在烧碱蒸发工序的应用

采用导波雷达液位计测量烧碱蒸发罐液位,阐述了导波雷达液位计的测量原理和优点。通过在蒸发工序的实际应用,证明导波雷达液位计在烧碱蒸发工序应用中的可行性和可靠性。     

咪鲜胺在粤浙两地水稻和土壤中残留动态

为了评价咪鲜胺在水稻上使用后的残留动态及环境安全性，在广东、浙江两地同时进行了咪鲜胺在水稻上的残留动态试验。结果表明：在广东地区，咪鲜胺在植株中的半衰期为2．59d，在土壤中的半衰期为2．46d，在稻田水的半衰期为0．46d；在浙江地区，咪鲜胺在植株中的半衰期为3．08d，在土壤中的半衰期为1．89d，在稻田水的半衰期为1．52d。收获的水稻糙米中咪鲜胺最终残留量均低于0．5mg／kg。     

Physiological effects of alarm chemosignal emitted during the forced swim test

Two experiments were conducted. In the first, male rats were immersed for 25 min in fresh water or water previously swum in by another rat. Control rats were not immersed in water. Rats tested in water previously swum in by another rat were significantly less immobile than rats tested in fresh water. Water immersion resulted in significant increases in serum corticosterone, glucose, and phosphorus levels, a decrease in potassium levels, and a higher phosphorus/potassium ratio, compared to nonimmersed controls regardless of water condition. When the two water-immersed groups were compared, rats tested in previously swum water had significantly higher glucose and significantly lower potassium levels and a higher phosphorus/potassium ratio than rats tested in fresh water. Immobility times were significantly correlated with the phosphorus/potassium ratio. In the second experiment, blood gases were measured prior to testing and at 25 min after immersion in rats tested in fresh and previously swum water. Rats in soiled water hypoventilated to a significantly greater extent than rats in fresh water but did not differ significantly in blood oxygenation. These two studies demonstrate that alarm chemosignals can produce physiological effects in conspecifics.     

Evaluation of surfactant-aided degumming of vegetable oils by membrane technology

The first step in the process of vegetable oil refining is degumming, in which phospholipids and mucilaginous gums are removed that otherwise result in a low-grade oil. A membrane process is remarkably simple yet potentially offers many advantages in degumming. Studies were conducted on surfactant-aided membrane degumming with soybean and rapeseed oils in a magnetically stirred flat membrane batch cell with different types of microfiltration membranes. The reduction of phospholipids in soybean oil was in the range of 85.8–92.8% during the membrane process. The phosphorus content of membrane permeates of soybean oil was in the range of 20–58 mg/kg. Crude rapeseed oil contained higher amount of nonhydratable phospholipids and hence resulted in lower reduction in phospholipids, in the range of 66.4–83.2%. Addition of hydratable phospholipids could improve the efficiency of degumming in the membrane process without using any electrolyte, resulting in improvement of quality as well as quantity of the phospholipids.     

DIMBOA Glucoside, a Wheat Chemical Defense, Affects Host Acceptance and Suitability of Sitobion avenae to the Cereal Aphid Parasitoid Aphidius rhopalosiphi

The influence of hydroxamic acids (Hx), plant secondary metabolites associated with aphid resistance in wheat, on the host acceptance and suitability of the aphid Sitobion avenae to the cereal aphid parasitoid Aphidius rhopalosiphi was evaluated. Aphids showed a reduction in mean relative growth rate and in body size in the wheat cultivar with higher Hx level. Reduction in aphid size was related to a decreased success in avoiding parasitoid oviposition. A minor increase in A. rhopalosiphi developmental time was observed in aphids feeding on the higher Hx cultivar. Experiments with different concentrations of DIMBOA glucoside, the main Hx in wheat, in artificial diets showed an increase in parasitoid developmental time at the highest concentration, with no change in other performance variables. The evidence is discussed in relation to the compatible utilization of host-plant resistance and biological control in integrated pest management.     

污泥生物炭中氮硫行为及环境效应研究进展

污泥生物炭中氮硫元素含量高，其氮硫行为和环境效应对全球气候变化的影响不容忽视。以往的研究中，研究者往往以富碳生物炭作为主要研究对象，关注碳对全球气候变化的行为和功效，而对氮硫元素的作用关注不够。本文从原始污泥基本性质到其热解过程，再到生物炭的老化，逐步对污泥生物炭整个生命周期内氮硫的行为及其环境效应研究进行综述，并对未来应注重开展的研究方向进行展望，为生物炭中氮硫元素固定、释放及与之关联的环境效应和温室气体排放控制研究提供理论基础。分析表明，污泥中氮元素含量普遍高于硫元素，且热解过程中氮比硫更容易转移至气相产物。氮硫元素随热解温度的增加，在三相产物中的分配都是炭中持续减少，油中先增后减，气中一直增加。高温（＞800℃）条件下，气相中的氮含量高于固相，而硫元素则仍然主要存在于固相中。污泥生物炭老化及其环境效应研究表明，污泥生物炭氮硫元素与土壤的相互作用及其温室效应问题在今后的研究中应引起重视。     

精-异丙甲草胺在大豆及土壤中的残留动态

为了评价精-异丙甲草胺在大豆上的残留动态及环境安全性,在天津、吉林两地同时进行了精-异丙甲草胺在大豆上的残留动态试验.结果表明,天津地区精-异丙甲草胺在大豆植株中的半衰期为19.1 d,在土壤中的半衰期为27.9 d;吉林地区精-异丙甲草胺在大豆植株中的半衰期为21.4 d,在土壤中的半衰期为34.1 d.收获的大豆籽粒中精-异丙甲草胺最终残留量均为未检出.     

H-Ferritin Produced by Myeloid Cells Is Released to the Circulation and Plays a Major Role in Liver Iron Distribution during Infection

During infections, the host redistributes iron in order to starve pathogens from this nutrient. Several proteins are involved in iron absorption, transport, and storage. Ferritin is the most important iron storage protein. It is composed of variable proportions of two peptides, the L- and H-ferritins (FTL and FTH). We previously showed that macrophages increase their expression of FTH1 when they are infected in vitro with Mycobacterium avium, without a significant increase in FTL. In this work, we investigated the role of macrophage FTH1 in M. avium infection in vivo. We found that mice deficient in FTH1 in myeloid cells are more resistant to M. avium infection, presenting lower bacterial loads and lower levels of proinflammatory cytokines than wild-type littermates, due to the lower levels of available iron in the tissues. Importantly, we also found that FTH1 produced by myeloid cells in response to infection may be found in circulation and that it plays a key role in iron redistribution. Specifically, in the absence of FTH1 in myeloid cells, increased expression of ferroportin is observed in liver granulomas and increased iron accumulation occurs in hepatocytes. These results highlight the importance of FTH1 expression in myeloid cells for iron redistribution during infection.     

Incubating superphosphate in ‘dry’soil can reduce its effectiveness

Single superphosphate was incubated for six months at 25°C in soil which had been subject to one of three moisture treatments. These were: dried in a glasshouse, dried at a constant temperature of 25°C, or moist soil. Phosphorus (P) effectiveness was then compared with effectiveness of P from freshly-applied superphosphate using yields of wheat (Triticum aestivum) and triticale (×Triticosecale) tops in pot experiments.Incubation in soil which had been dried at 25°C did not decrease the effectiveness of the P. Incubation in moist soil decreased it to about 20% of the effectiveness of freshly-applied P in one case and to about 50% in the other case. Incubation in soil which had been dried in a glasshouse also decreased its effectiveness. The decrease varied with conditions, but in two cases the P was 70% as effective as freshly-applied P, and in one case only 45% as effective. Presumably sufficient moisture was present in the soil dried in the glasshouse to enable water-soluble P present in the fertilizer to react with the soil.     

Effects of decomposing rice straw on growth of and nitrogen fixation byRhizobium

Five phenolic compounds produced by decomposing rice straw and sterile extracts of decomposing rice straw in soil were very inhibitory to growth of three strains ofRhizobium. The effects were additive and in several instances synergistic. The phenolic compounds also reduced nodule numbers and hemoglobin content of the nodules in two bean (Phaseolus vulgaris) varieties. Extracts of decomposing rice straw in soil (same concentration as in the soil) significantly reduced N₂ fixation (acetylene reduction) in Bush Black Seeded beans. This may explain in part the great reduction in soybean yields in Taiwan following rice crops when the rice stubble is left in the field.