NUCLEATION,POLYMERIZATION, AND PRECIPITATION OF FeOOH1     

PA HO HSU 《European Journal of Soil Science》1972,23(4):409-419

Fresh Fe(ClO₄)₃ solutions, 0.01 M or 0.001 M in iron (III), were seeded with iron (III) hydroxide brown sols and the reaction processes were investigated. In two experiments, HC1O₄ was added to fresh Fe(ClO₄)₃ solutions to lower their degrees of super saturation with respect to iron (III) hydroxide. Depending upon the quantity of seeding solution added, it was found that samples differed greatly in appearance and in the stability during ageing. With a small amount of seeding solution added and following a relatively long induction period, the sample rapidly developed to a dense, cloudy yellow suspension with FeOOH precipitate settled shortly afterwards. With an increased amount of seeding solution added, the sample gradually became more brownish and less turbid and eventually a clear brown sol was observed. Although α-FeOOH was the major hydrolysed species in all samples, a yellow precipitate which settled under gravity was found only in those containing a small quantity of seeding solution. The above results provide experimental evidence supporting the hypothesis (Hsu and Ragone, 1972) that the initial number of nuclei relative to the concentration of mono-meric species is the key factor governing the appearance and the stability of an hydrolysed iron (III) solution. In another experiment, varying amounts of a seeding solution were added to a fresh, pure 0.001 M Fe(ClO₄)₃ solution to which no HC1O₄ was added. All samples rapidly hydrolysed to clear brown sols in less than 6 hours and no noticeable seeding effect was observed. It is suggested that a pure 0.001 M Fe(ClO₄)₃ solution is highly supersaturated with respect to iron (III) hydroxide and a large number of nuclei spontaneously form in situ shortly after preparation.  相似文献   

土壤电化学特牲的研究——Ⅰ.水稻土的电导与其肥力的关系     

于天仁  何羣  蒋柏藩  宣家祥  谢建昌 《土壤学报》1959,7(Z2):145-158

1.设计了一个在田间直接测定水稻土的电导的电导池,用以鉴别水稻土的肥力状况。根据条件试验,在水稻生长期间通常变动的水分含量范围以内,水分含量的差别可以不予考虑。土壤胶体本身的电荷在电导上的贡献也很小,所以一般也不必考虑。土壤含砂粒较多时,应该加以适当的改正值。2.根据大量的田间测定结果,在酸性的水稻土中,电导与肥力水平成明显相关。施肥的数量和种类对土壤电导发生显著的影响。由于水稻对养分的吸收,所以根际土壤的电导较根外为低,并且随着水稻的生长,而使土壤电导降低。3.酸性水稻土的干土渍水后电导的增加数值与土壤的肥力水平成正相关。这种电导的增加,基本上是由于有机质的分解所致。4.根据与化学分析的对照结果,土壤溶液的电导与阳离子的浓度成明显相关。在引起酸性水稻土电导的阳离子中,钙镁占90—95%,钾占2—8%,铁和铵的数量都在1%以下。5.作者根据研究结果,认为电导可以作为鉴别酸性水稻土的肥力水平的一个简便的综合性参考指标。  相似文献   

Allelopathic potential of cucumber (Cucumis sativus) on barnyardgrass (Echinochloa crus-galli)     

HO LE THI  PHAM THI PHUONG LAN  DUONG VAN CHIN  HISASHI KATO-NOGUCHI 《Weed Biology and Management》2008,8(2):129-132

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关于旅大地区小麦秆锈菌和叶锈菌夏孢子世代的越冬问题     

曾广然  何健三  張国淳  周声学  薛立信 《植物病理学报》1957,3(1):87-97

 关于小麦秆锈和叶锈的越冬问题,国外业巳有许多报告^{[10,13,14,15,16,17,18]}。国内在小麦锈菌越冬方面也有一些报导。  相似文献   

Added triacylglycerols do not hasten hemoglobin-mediated lipid oxidation in washed minced cod muscle     

Undeland I  Hultin HO  Richards MP 《Journal of agricultural and food chemistry》2002,50(23):6847-6853

Hemoglobin-mediated lipid oxidation in washed, minced cod muscle was related to the triacylglycerol to membrane lipid ratio. The same rapid development of thiobarbituric acid reactive substances (TBARS) and painty odor occurred with and without the presence of up to 15% menhaden oil. Without hemoglobin, development of TBARS and painty odor was slow, despite a high amount of hydroperoxides in samples with oil added (1135 micromol/kg muscle). This suggested that hemoglobin reacted by cleaving preformed hydroperoxides into secondary oxidation products. Nearly doubling the hemoglobin concentration approximately doubled the extent of lipid oxidation with and without added oil. This indicated that hemoglobin was limiting for the oxidation reaction. The noneffect of added oil suggests that membrane lipids and/or preformed membrane lipid hydroperoxides provided sufficient substrate in hemoglobin-catalyzed oxidation of washed minced cod muscle. Fe(2+-)ADP did not induce any oxidation of washed minced cod with/without added oil. Results suggest that lipid oxidation in fatty fish may be more related to the quantity and type of the aqueous pro-oxidant and the membrane lipids than to variations in total fat contents.  相似文献   

Stabilisation with dorsal and ventral fixation of a traumatic cervical instability in a dog   总被引：1，自引：1，他引：0  

A Ozak  HO Nisbet  C Yardimci  YS Sirin 《Australian veterinary journal》2009,87(10):413-416

This case study reports the outcome of dorsal and ventral stabilisation of a traumatic cervical instability in a dog. A 2-year-old, male Pointer was admitted following a motor vehicle accident. Clinical examination revealed non-ambulatory tetraparesis, severe neck pain and upper motor neuron changes in all limbs. Deep pain response was present. Subluxation of C2/3 and fractures of the dorsal spinous process and lamina of C2 were observed on radiographs. Ventral stabilisation was performed with screws and bone cement (polymethylmethacrylate). For dorsal fixation of the fractures, screws and cerclage wire were used. The dog stood up independently after 1 month, was able to walk 1.5 months postoperatively and had recovered completely at 1 year following surgery. We conclude that combined stabilisation techniques are effective for this type of cervical fracture in which the dorsal, middle and ventral structures of the vertebra are severely disrupted.  相似文献   

Effects of glucagon on hypoglycemia and ketonemia in pregnant ewes     

HO P  REBER EF 《American journal of veterinary research》1957,18(67):342-344

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Distribution and genetic uniformity of an endangered aquatic plant, Ranunculus kadzusensis, in a South Korean rice paddy     

YOUN-BONG KU  HYUN KYUNG OH  JAE HO LEE  HAK YANG KONG  JI-HYON KIL  KANG-HYUN CHO 《Weed Biology and Management》2007,7(2):120-123

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MAGNETIC RESONANCE IMAGING FEATURES OF OBLIQUE AND STRAIGHT DISTAL SESAMOIDEAN DESMITIS IN 27 HORSES     

SARAH N. SAMPSON  ROBERT K. SCHNEIDER  RUSSELL L. TUCKER  PATRICK R. GAVIN  CHAD J. ZUBROD  CHARLES P. HO 《Veterinary radiology & ultrasound》2007,48(4):303-311

Injury to the oblique and straight distal sesamoidean ligaments is becoming recognized as a more common cause of lameness in horses than was previously thought. The purpose of this study was to review the magnetic resonance (MR) imaging findings of 27 horses affected with desmitis of the oblique and/or straight distal sesamoidean ligament and determine long-term prognosis for horses with this diagnosis. Imaging was performed with horses in right lateral recumbency in a high-field 1 T magnet. All horses had lameness localized to the digit or metacarpophalangeal/metatarsophalangeal joint region with diagnostic local anesthetic blocks. Ten horses had forelimb lameness and 17 horses had hind limb lameness. MR imaging revealed abnormalities in the oblique distal sesamoidean ligaments in 18 horses, in the straight distal sesamoidean ligament in three horses, and in both the oblique and straight distal sesamoidean ligament in six horses. Treatment consisted of a 6-month rest and rehabilitation program in all horses. The digital flexor tendon sheath was injected with methylprednisolone acetate and hyaluronic acid in 22 horses to decrease inflammation in the injured ligaments before starting the rest and rehabilitation program. Two horses had ligament splitting performed, one in the oblique distal sesamoidean ligament and one in the straight distal sesamoidean ligament. MR imaging is an effective method for diagnosing injury to the oblique and straight distal sesamoidean ligaments in horses. Treatment, primarily a 6-month rest and rehabilitation program, allowed 76% of the horses to successfully resume performance.  相似文献   

Optical chlorophyll measurements as predictors of total nitrogen,nitrogen fractions and in vitro ruminal nitrogen degradability in tropical grass forages     

Martin Hughes  Victor Mlambo  Cicero HO Lallo  Paul GA Jennings 《African Journal of Range and Forage Science》2016,33(4):253-264

This study evaluated whether the FieldScout CM 1000 NDVI and Yara N–Tester models can produce accurate and reliable estimates of nitrogen (N), buffer-soluble nitrogen (BSN), buffer-insoluble nitrogen (BISN), non-protein nitrogen (NPN) and in vitro ruminal nitrogen degradability after 3, 12 and 24?h incubation (ND3, ND12 and ND24) in three tropical grasses: Brachiaria hybrid, Megathyrsus maximus and Paspalum atratum. Correlation between the Yara N-Tester and N, BISN and in vitro ruminal N degradability of the Brachiaria hybrid and M. maximus were high (r 0.67–0.83). The Yara N-Tester accounted for 81% and 86% (p 0.000) of N variability in the Brachiaria hybrid and M. maximus, respectively. The Yara N-Tester prediction models explained 72% and 70% (p 0.000) BISN variability in the Brachiaria hybrid and M. maximus, respectively. In vitro ND24 of the Brachiaria hybrid (R?2 0.75) and M. maximus (R?2 0.75) was also best predicted with the Yara N-Tester. Model validation showed generally low (≤0.90) concordance correlation coefficients except for Yara N-Tester N and ND24 in M. maximus. Random error was the main source of error. We conclude that the accuracy of the Yara N-Tester prediction models was superior to that of the FieldScout CM 1000 NDVI models, and that the Yara N-Tester can produce accurate and reliable estimates of Brachiaria hybrid and M. maximus N and M. maximus ND24.  相似文献