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On the dynamically formed oxide films in molten Mg

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Journal of Magnesium and Alloys 2020年第1期8卷 219-230页

作者： mohammad mahdi jalilvand Mehdi Akbarifar Mehdi Divandari Hassan Saghafian School of Metallurgy and Materials Engineering Iran University of Science and Technology(IUST)NarmakTehran16846-13114Iran

The so-called“Oxide/Metal/Oxide sandwich”method is one of the technique used to investigate the dynamic oxidation of metals which happens during the casting *** this study,characteristics of the oxide films formed on the molten magnesium in dynamic conditions have been investigated using the aforementioned *** air bubbles were released into the cast sample at the pressure of 0.2 atm through a quartz tube of 1 mm internal *** interface of two adjacent entrapped bubbles is considered as the Oxide/Metal/Oxide(OMO)*** sandwiches were characterized by the aid of the optical and scanning electron microscopy and also X-Ray diffraction *** different approaches,including measuring the width of the folds formed on the oxide films and the edge of the sandwiches,were used to estimate the thickness of the *** thicknesses were estimated to be in the range of 200 to 800 *** features such as fold,wrinkle,and crack were observed on the OMO *** the microscopic scale,the oxide films were rough and *** is attributed to the non-protective behavior of oxide *** XRD patterns indicated that the oxide films formed on the pure molten magnesium in dynamic conditions are crystallized MgO.

关键词： Dynamic oxidation Bifilm Magnesium Oxide films Casting defects

Effect of canopy gap size and ecological factors on species diversity and beech seedlings in managed beech stands in Hyrcanian forests

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Journal of Forestry Research 2012年第2期23卷 217-222页

作者： Kambiz Abrari Vajari Hamid jalilvand mohammad Reza Pourmajidian Kambiz Espahbodi Alireza Moshki Faculty of Natural Resources Sari Agriculture Sciences and Natural Resources University Iran Research Center in Agricultural and Natural Resources of Mazandaran Province Sari Iran Soil science of temperate and boreal ecosystems Institute Faculty of forest science and forest ecology Georg-August University of Goettingen Germany

We studied the species diversity of the herb layer and ecological factors in harvest-created gaps in beech stands under a single-tree selection system in Northern Iran. To determine diversity, the number of beech seedlings, and other ecological factors, 16 gaps were selected and subplots of 5 m2 were positioned at the centre and at the cardinal points of each gap. Species richness and Simpson diversity index increased with increasing gap area as did numbers of seedlings. With increasing humus layer thickness, species richness declined but the Hill evenness index increased. Species richness increased with increasing light availability. There was no relationship between crown radii of beech trees and diversity indices. Correlations between environmental factors and numbers of individuals of some species in the herb layer were not significant except in a few cases. The results help explain the effects of man-made gaps on the dynamics of managed beech stands and this benefits evaluation of silvicultural operating plans.

关键词： beech gap herbaceous species diversity Hyrcanian for- ests

The effect of single-tree selction system on soil properties in an oriental beech stand of Hyrcanian forest, north of Iran

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Journal of Forestry Research 2011年第4期22卷 591-596页

作者： Kambiz Abrari Vajari Hamid jalilvand mohammad Reza Pourmajidian Kambiz Espahbodi Alireza Moshki Academic member of Agriculture Faculty Lorestan University Ph. D candidate of Forestry Faculty of Natural Resources Sari Agriculture Sciences and Natural Resources University Iran Forestry Department Faculty of Natural Resources Sari Agriculture Sciences and Natural Resources University Iran Research Center in Agricultural and Natural Resources of Mazandaran Province Sari Iran Ph.D candidate Soil science of temperate and boreal ecosystems Institute Faculty of forest science and forest ecology Georg-August university of Goettingen zip code:37077 Germany

A case study was conducted in beech forests of northern Iran to determine the effect of the created gaps on some soil properties in beech stand. Changes of soil properties in small （60-150 mE）, medium （151-241 mE）, large （242-332 m^2） and very large （333-550 m^2） gaps, as well as under closed stands were studied eight years after-the gap creation. Soil samples were taken from three depths, 0-10, 10-20 and 20-30 cm. The gaps were different from their around undisturbed stands in terms of the following soil parameters： Mg^＋2 concentration of 0-10 cm at medium gap size, bulk density of 10-20 cm at very large gap size as well as K^＋ and Ca^＋2 concentrations at 20-30 cm at small and large gap sizes, respectively. Furthermore, the size of the gaps had no effect on soil characteristics through the whole profile. Water saturation percent （Sp %） at 0-10cm as well as P and Mg^＋2 at 20--30 cm was different amongst undisturbed stands around different gap sizes. The center and the edges of the gap were different only in terms of organic carbon at the depth of 10-20 cm. Significant differences were observed between gaps and closed canopy regarding P and Ca^＋2 at depth 0--10 cm and 10-20 cm, respectively. It can be concluded that applied silvicultural system for harvesting trees which created these gaps might be suitable for conservation and forest management in the region.

关键词： gap soil Fagus orientalis single-tree selection system northern lran

Reproduction of juniper (Juniperus polycarpos) in Khorasan Razavi, Iran

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Forestry Studies in China 2013年第3期15卷 231-237页

作者： Hamid AHANI Hamid jalilvand Seyed mohammad HOSSEINI NASR Hossein SOLTANI KOUHBANANI mohammad Reza GHAZI Hassan mohammadZADEH Agricultural Sciences and Natural Resources University of Sari Iran Natural Resources and Watershed Administration of Khorasan Razavi Iran Torogh Nursery Natural Resources and Watershed Administration of Khorasan RazaviIran Natural Resources and Watershed Administration of Kalat Naderi Khorasan RazaviIran

Juniperus species （juniper） are resistant to drought and have medicinal properties. In order to investigatethe condition of juniper reproduction and prevent a decline in its area, largely caused by problems in natural regeneration, the asexual reproduction of juniper has received special attention besides its sexual propagation. Among the six species of juniper in Iran, the most abundant are Juniperus polycarpos and J. excelsa. Juniperus polycarpos is ambi-sexual and J. excelsa unisexual. We show that collecting seeds in September provided for better germination than in November. In sexual propagation 82.0% and in asexual （graft） 47.6% success were achieved. Compared to a mixture of water, lime and hormones, a natural treatment of only water had better results. Diurnal change of temperature increased germination of juniper seeds over a constant temperature. Aphyllous stem cuttings from mature and old trees are less successful in rooting than leafy cuttings of juniper saplings. A treatment with Aaterra significantly reduced the percentage of rooted cuttings and total root length. Aliette, Fongarid, Octave, Benomyl, Delsene M and Maneb fungicides significantly increased the percentage of rooted cuttings but did not affect total root length. Autumn explants formed more calli than spring explants. Successful multiplication was achieved by treating buds with a mixture of 0.7% polyvinyl pyrrolidone （PVP） and 2% sucrose and cultured in a basal MS or WRC medium, with a maximum number of new buds. In consideration of extracted material of juniper species in remedy of infectious, fungus, contagious diseases as well as for drought resistance and longevity of this species in severe arid environmental conditions and various industrial applications, reproduction and seed production by micro propagation and biotechnology are necessary.

关键词： Juniperus polycarpos Juniperus excelsa micro propagation reproduction Iran

Portal hemodynamics as predictors of high risk esophageal varices in cirrhotic patients

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World Journal of Gastroenterology 2008年第12期14卷 1898-1902页

作者： mohammad K Tarzamni mohammad H Somi Sara Farhang Morteza jalilvand Liver and Gastrointestinal Diseases Research Center Tabriz University of medical sciences Tabriz East Azerbaijan Iran

AIM： To evaluate portal hypertension parameters in liver cirrhosis patients with and without esophageal varices （EV）. METHODS： A cohort of patients with biopsy confirmed liver cirrhosis was investigated endoscopically and with color Doppler ultrasonography as a possible noninvasive predictive tool. The relationship between portal hemodynamics and the presence and size of EV was evaluated using uni- and multivariate approaches. RESULTS： Eighty five consecutive cirrhotic patients （43 men and 42 women） were enrolled. Mean age （± SD） was 47.5 （± 15.9）. Portal vein diameter （13.88 ± 2.42 vs 12.00 ± 1.69, P 〈 0.0005） and liver vascular index （8.31 ± 2.72 vs 17.8 ± 6.28, P 〈 0.0005） were found to be significantly higher in patients with EV irrespective of size and in patients with large varices （14.54 ± 1.48 vs 13.24 ± 2.55, P 〈 0.05 and 6.45 ± 2.78 v$10.96 ± 5.05, P 〈 0.0005, respectively）, while portal vein flow velocity （13.25 ± 3.66 vs 20.25 ± 5.05, P 〈 0.0005）, congestion index （CI）（0.11 ± 0.03 vs 0.06 ± 0.03, P 〈 0.0005）, portal hypertensive index （2.62 ± 0.79 vs 1.33 ± 0.53, P 〈 0.0005）, and hepatic （0.73 ± 0.07 vs 0.66 ± 0.07, P 〈 0.001） and splenic artery resistance index （R/）（0.73 ± 0.06 vs 0.62 ± 0.08, P 〈 0.0005） were significantly lower. A logistic regression model confirmed spleen size （P = 0.002, AUC 0.72） and portal hypertensive index （P = 0.040, AUC 0.79） as independent predictors for the occurrence of large esophageal varices （LEV）. CONCLUSION： Our data suggest two independent situations for beginning endoscopic evaluation of compensated cirrhotic patients： Portal hypertensive index 〉 2.08 and spleen size 〉 15.05 cm. These factors may help identifying patients with a low probability of LEV who may not need upper gastrointestinal endoscopy.

关键词： Liver cirrhosis Doppler ultrasound Portalhemodynamics Esophageal varices Prediction

Effect of shelterwood cutting method on forest regeneration and stand structure in a Hyrcanian forest ecosystem

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Journal of Forestry Research 2010年第3期21卷 265-272,395页

作者： mohammad Reza Pourmajidian Hamid jalilvand Asghar Fallah Seyed Ataollah Hosseini Aidin Parsakhoo Amin Vosoughian Ali Rahmani Department of Forestry Faculty of Natural ResourcesSari Agricultural Sciences and Natural Resources University Department of Forestry Faculty of Natural ResourcesMazandaran University

A study was carried out to evaluate the effect of shelterwood cutting methods on stand structure and regeneration density. Data were collected from a northern hardwood forest stands in Iran with Fagus orientalis Lipsky as dominant species, with/without shelterwood cutting operation. Results clearly demonstrate that the management of Fagus orientalis Lipsky with shelterwood cutting system affected the frequency and diversity of the understory herbaceous species. The frequency of Viola silvestris Lam., Asperula odorata L., Carex spp. and Rubus hyr-canus Juz increased significantly after shelterwood cutting. The DBH （diameter at breast height） of commercial species in control stands （57.50±2.15 cm） was greater than that in treated stands （50.67±1.88 cm）, whereas the total height of trees was similar between treated and control plots （21±0.5 m）. The number of Parrotia persica seedlings increased by 13.2% from 1995 to 2005 whereas the number of Fagus orientalis and Carpinus betulus seedlings significantly decreased from 1995 to 2005. In conclusion, it confirms that instead of shelterwood cutting method other silvicultural practices such as selection cutting method should be applied for the mountainous beech stands of Hyrcanian forests.

关键词： Shelterwood cutting stand structure regeneration Fagus orientalis Lipsky