电镀高饱和磁感应(B_s)CoNiFe软磁薄膜研究

研究了电沉积 CoNiFe 合金薄膜镀液中主盐离子浓度对膜层磁性能的影响。用振动样品磁强计(VSM)和四探针等方法测试分析了膜层的物理性能。结果表明膜层的物理性能与合金镀液中的主盐离子浓度密切相关,镀液中Ni2+、Fe2+、Co2+浓度分别为0.2、0.012和0.063mol/L时,电沉积的 CoNiFe合金膜层的电磁性能较佳。其饱和磁化强度 Bs 达 1.9T,矫顽力Hc 为91.5A/m,电阻率为45μΩ·cm,在 1MHz下磁导率μi 为602。

Electrodeposition behavior of nanocrystalline CoNiFe soft magnetic thin film

The electroplating behavior of nanocrystalline CoNiFe soft magnetic thin film with high saturation magnetic flux density (Bs>2.1 T) and low coercivity (Hc) was investigated using cyclic voltammetry and chronoamperometry methods in conjunction with the scanning electron microscopy (SEM/EDX). The results show that, under the experimental conditions, the co-deposition of CoNiFe film behaves anomalously due to the atomic radii of iron series elements following the order of rFe>rCo>rNi. In the case of lower electroplating current density, the co-deposition of CoNiFe film follows a 3-D progressive nucleation/growth mechanism, while in the case of higher electroplating current density, which follows a 3-D instantaneous nucleation/growth mechanism. Meanwhile, the change of nucleation mechanism of CoNiFe film with electroplating current density was interpreted theoretically in the light of quantum chemistry.

Warming hiatus-and evergreen conifers in Altay-Sayan Region,Siberia

"Warming hiatus" occurred in the AltaySayan Mountain Region, Siberia in c. 1997–2014. We analyzed evergreen conifer(EGC) stands area(satellite data) and trees(Siberian pine, Pinus sibirica Du Tour, Siberian fir, Abies sibirica Ledeb.) growth increment(dendrochronology data) response to climate variables before and during the hiatus. During the hiatus, EGC area increased in the highlands(>1000 m)(+30%), whereas at low and middle elevations(<1000 m. a.s.l.) the EGC area decreased(-7%). The EGC area increase was observed on the rain-ward northwest slopes mainly. In highlands, EGC area increase mainly correlated with summer air temperature, whereas at low and middle elevations EGC area decrease correlated with drought index SPEI and vapor pressure deficit(VPD). EGC mortality(fir and Siberian pine) in lowland was caused by the synergy of water stress(inciting factor) and barkbeetle attacks(contributing factor). Tree growth increment(GI) dynamics differs with respect to elevation. At high elevation(1700 m) GI permanently increased since warming onset, whereas at the middle(900 m) and low elevations(450 m) GI increased until c. 1983 yr. with followed depression. That GI "breakpoint" occurred about a decade before hiatus onset. In spite of growth depression, during hiatus GI was higher than that in pre-warming period. At high elevation, GI positively responded to elevated June temperatures and negatively to moisture increase(precipitation, root zone moisture content, VPD, and SPEI). At low elevation GI negatively responded to June temperatures and positively to moisture increase. For both, low and high elevation, these patterns persisted throughout the study period(1967–2014). On the contrary, at middle elevations GI dependence on climate variables switch after breakpoint year(1983). Before breakpoint, June air temperature(positive correlation) and moisture(negative correlations) controlled GI. Further temperature increase leads GI depression and switched correlation signs to opposite(from positive to negative with temperature, and from negative to positive with moisture variables).

Distribution and variability of n-alkanes in waxes of conifers

Epicuticular waxes have vital roles in the growth and development of plants and in defense. Conifers have a considerable amount of waxes on their cones and leaves.Here we characterized the n-alkane composition of Iranian conifers, including Juniperus oblonga, J. foetidissima, J.sabina, J. communis subsp. hemisphaerica, J. excelsa,Cupressus sempervirens, Platycladus orientalis from Cupressaceae and Taxus baccata from Taxaceae for the first time using GC-FID analyses. In the waxes, 25 n-alkane homologs with chain lengths ranging from C7 to C32 were identified. Short-chain n-alkanes were dominant in almost all samples with some exceptions. Complementary studies to elucidate complete wax constituents of Iranian conifers and n-alkane distribution pattern as a function of geographical and bioclimatic variables are recommended.

Impacts of Coriaria nepalensis colonization on vegetation structure and regeneration dynamics in a mixed conifer forest of Indian Central Himalaya

This study evaluated impacts of Coriaria nepalensis Wall.colonization on soil characteristics,vegetation structure and composition,regeneration status and expected future compositional changes,biomass and carbon stock in tree species of a mixed conifer forest of Central Himalaya.Three sites(1 ha each in an old landslide area)differing in Coriaria density(low:20 individuals ha^(-1);medium:120 indiv.ha^(-1);high:190 indiv.ha^(-1))were used to enumerate the tree species.A total of 9 tree species and 2830 individuals were recorded from the three study sites that represented a gradient of Coriaria density.Number of species varied from 3 to 7 and the individuals from 690 to 1270 per site with lowest numbers at low Coriaria density and highest at medium Coriaria density.The number of seedlings increased with increasing Coriaria density,and the sites were unique in their seedling composition,indicating marked temporal dynamics.Site wise regeneration analysis showed that regeneration was poor at the site with low Coriaria density and good at the high-density site where many species emerged as seedlings.These results indicate that the ameliorative effects of Coriaria in terms of soil buildup,and accumulation of nutrients and organic matter helped more species to colonize the area.This facilitative ability of Coriaria can be used to restore degraded forest ecosystems of Indian Central Himalaya.

A Study of Collecting Robot of Conifer Cone

The collecting robot of conifer cone mainly consists of walking mechanism and manipulator. Manipulator has 5 freedoms. The main technical parameters of this robot are as follows :maximum height of collecting is 14m, maximum radius of collecting is 68m, velocity of collecting is 0.65 m/s, and the maximum force of collecing is 2500N.

Vegetation-environment relationship in conifer dominating forests of the mountainous range of Indus Kohistan in northern Pakistan

Environmental variables play a crucial role in shaping vegetation structure,mainly in mountainous ecosystems.Different studies have attempted to identify the environment-vegetation relationship of Conifer Dominating Forests(CDF)worldwide.However,due to differences in local climate and soil composition,different environmental drivers can be found.By applying multivariate analysis techniques,this study investigated the vegetation-environment relationship of CDF of Indus Kohistan in northern Pakistan.Our results showed that CDF of Indus Kohistan are distributed in five distinct ecological groups,which are dominated by different trees and understory species.A total of 7 trees and 71 understory species were recorded from the sampling sites.Cedrus deodara was the leading species among four groups,having the highest importance value(IV),density and basal area.Group I was dominated by Pinus wallichiana with the second highest importance value,density and basal area.In addition,elevation,slope,maximum water holding capacity(MWHC),soil moisture(SM),total organic matter(TOM),sodium,phosphorus and nickel showed highly significant influence on composition and distribution pattern of Indus Kohistan vegetation.Therefore,this study shows a new evidence of vegetation-environment relationship,pointing out specific drivers of vegetation structure in CDF of Indus Kohistan region in northern Pakistan.

EFFECTIVENESS OF ACEPHATE IMPLANTS IN PROTECTING CONES FROM INSECT DAMAGE IN SOME CONIFERFORESTS OF NORTHEASTERN CHINA

Stem implants of acephate were tentatively used to contfol cone and seed insects in Northeastern China in 1993. Experiments considered in a Siberian larch seed orchard and mother-tree stands of Korean pine and Korean spruce that promising control of major cone pests, including cone tlies, cone-worms and seed-worms, was obtained in all of the conifer species but treatment did not reduce significantly damage due to seed chalcids. Acephate implants did not seem to affect seed germination.

STATISTICAL ANALYSIS OF TEMPERATURES ON BOTH THE UPPER AND LOWER BOUNDARIES OF SUB－ALPINE DARK CONIFER FORESTS IN CHINA

Temperature of every month on both the upper and lower boundaries of sub-alpine dark conifer forests at various sites in China are estimated in terms of their distributions and temperature records. Based on these estimated data, the heat factors to influence and control the distribution and growth of subalpine dark conifer forests in China are discussed. It is found that the most important heat index to influence and control the distribution and growth of subalpine dark conifer forests is neither the mean temperature in the warmest month, nor the maximum or minimum temperatures, but monthly accumulated temperature of>0℃ or monthly effective accumulated temperature of>5℃.When monthly accumulated temperature of>0℃ is more than 40℃, or monthly effective accumulated temperature of>5℃ is over 50℃, sub-alpine dark conifer forests cannot grow well. When monthly accumulated temperature of>5℃ is less than 60℃, sub-alpine dark conifer forests can not grow at all. When monthly effective accumulated temperature of>5℃ is in the range 15℃-45℃, subalpine dark conifer forests in China can grow well. The ecological significance of temperature in May and September, and in summer half year are discussed.

In vitro cholinesterase inhibitory and antioxidant effect of selected coniferous tree species

Objective:To explore cholinesterase inhibitory and antioxidant effect of six coniferous trees(Abies bornmulleriana,Picea pungens,Juniperus communis,Cedrus libani,Taxus baccata,and Cupressus sempervirens var.horizantalis).Methods:Acetone(Ace),ethyl acetate(EtOAc),and ethanol(EtOH)extracts prepared from the needles and shoots of the six coniferous trees were screened for their acetylcholinesterase(AChE)and butyrylcholinesterasc(BChE)inhibitory activity at 100μg/mL.Antioxidant activity of the extracts was tested using 2,2-diphenyl-1-picrylhydrazyl(DPPH)and N,N-dimethyl-p-phenylendiamine(DMPD)radical scavenging,nietal-chelation capacity,ferric-(FRAP)and phosphomolibdenum-reducing antioxidant power(PRAP)assays.All of the assays were performed in ELISA microplate reader.Total phenol and flavonoid amounts in the extracts were determined spectrophotometrically.Results:Among thirty-six extracts in total,the shoot-Ace extract of Cupressus sempervirens var.horizantalis exerted the highest inhibition against AChE[(54.84±2.51)%],while the needle-Ace extract of Cedrus libani was the most effective in inhibiting BChE[(67.54±0.30)%].The highest DPPH radical scavenging effect,FRAP and PRAP was observed in the shoot-Ace and EtOAc extracts from Taxus baccata.whereas all the extracts showed a variable degree of scavenging effect against DPMD radical.The shoot-EtOAc extract of Cedrus libani had the highest metalchelation capacity[(58.04±0.70)%].The shoot extracts of Taxus baccata were determined to have the richest total phenol content,which may contribute to its marked antioxidant activity.Conclusions:The conifer species screened in this study may contain cholinesterase-inhibiting and antioxidant properties,which might be useful against Alzheimer's disease.

In vitro propagation of conifers using mature shoots

Micropropagation mostly leads to the production of innumerable true-to-type plants. However, establishing pathogen-free explants through in vitro culture requires a precise management of time for the exposure of explants to antimicrobial chemicals. The application of antimicrobial chemicals must also be managed to impose the least injury on explants. This review discusses the contributions of micropropagation procedures, explant types, subculture duration, media ingredients and plant growth regulators to the in vitro response of conifer explants. Even though regeneration from mature conifer explants such as mature shoots are laborious, the chances of variation, induced in vitro, are unlikely.

Population structure,age and growth rates of conifer species and their relation to environmental variables at Malam Jabba,Swat District,Pakistan

This study focuses on age,growth rate and diameter distribution of pine forests in the Malam Jabba area,Swat District,Pakistan.Wood core samples were taken from twenty stands.Picea smithiana was the oldest at 234 years with a 112-cm diameter.Abies pindrow was 125 years with an 80-cm diameter while the oldest Pinus wallichiana was 122 years with 75-cm diameter.The fastest overall growth rate of 1.5±0.1 year/cm was for P.wallichiana on a west-facing aspect,while the slowest 5.8±2.6 year/cm growth was P.smithiana on an eastfacing exposure.P.wallichiana and A.pindrow exhibited marked differences in growth rates over a 5-year period.The highest growth was by P.wallichiana from 1966 to 2006.A.pindrow showed less growth over the same years,such pattern simultaneously reverse from 1911 to 1965.The relationship between diameter and age,diameter and growth rate and age and growth rate were correlated.P.wallichiana and A.pindrow ages were correlated with diameter and growth rates.P.smithiana age was positive correlated with diameter.Generally,topographic and edaphic factors did not show significant correlations with growth rates,although some appreciable correlations were recorded.The growth of P.wallichiana was correlated with elevation while A.pindrow was correlated with maximum water retaining capacity.Diameter and age produced uneven size classes and many size gaps,which could be the result of anthropogenic disturbances.

Ectomycorrhizal Fungi of Conifers and Their Economic Value From Xinjiang China

91 noteworthy ectomycorrhizal fungi associated with Larix sibirica Ledeb. etc. from Xing jiang are discussed. Hydnellum caeruleum(Horn. :Pers. )Karst. ,H. peckii Banker apud Peck,Cortinarius azureovelatus Orton,C. pinicola Orton, C. rickenianus Maire are new record to China. Among which 66 species are edible, 14 species are poisonous, 13 species are pharmaceutical, 22 species are probably anticancer.

Stand age structural dynamics of conifer, mixedwood, and hardwood stands in the boreal forest of central Canada

To study the effects of stand development and overstory composition on stand age structure, we sampled 32 stands representing conifer, mixedwood, and hardwood stand types, ranging in ages from 72 to 201 years on upland mesic sites in northwestern Ontario. We defined the stages of stand development as: stem exclusion/canopy transition, canopy transition, canopy transition/gap dynamics, and gap dynamics. Stand age structure of conifer stands changed from bimodal, bimodal, reverse-J, and bimodal, respectively, through the stages of stand development. Mixedwood and hardwood stands revealed similar trends, with the exception of missing the canopy transition/gap dynamic stage in mixedwoods. Canopy transition/gap dynamic stage in hardwoods showed a weaker reverse-J distribution than their conifer counterparts. The results suggest that forest management activities such as partial and selection harvesting and seed-tree systems may diversify standard landscape-level age structures and benefit wildlife, hasten the onset of old-growth, and create desired stand age structures. We also recommend that the determination of old-growth using the following criteria in the boreal forest: 1) canopy breakdown of pioneering cohort is complete and stand is dominated by later successional tree species, and 2) stand age structure is bimodal, with dominating canopy trees that fall within a relatively narrow range of age and height classes and a significant amount of understory regeneration.

Modeling of Growth Kinetics of Conifer Trees

The kinetics of growth of conifers is modeled by the dependence of the area of tree rings on time. The data on the growth of 46 coniferous trees varying in age from 35 to 242 years, found in the literature are analysed. To identify the common patterns in the growth kinetics, we investigate the series of standard increments of tree rings for pine, spruce, and larch. The curves obtained reflect adequately the ontogeny of trees. These allow the analysis of the environmental effects’ on the physiology of trees. In such a way the accelerated growth of trees in the Tunguska meteorite explosion zone is established. The proposed method of dendrochronology based on the area of tree rings is more adequate and informative than the method based on tree-rings’ widths.

Terpenoid Biosynthesis and Specialized Vascular Cells of Conifer Defense

Defense-related terpenoid biosynthesis in conifers is a dynamic process closely associated with specialized anatomical structures that allows conifers to cope with attack from many potential pests and pathogens. The constitutive and inducible terpenoid defense of conifers involves several hundred different monoterpenes, sesquiterpenes and diterpenes. Changing arrays of these many compounds are formed from the general isoprenoid pathway by activities of large gene families for two classes of enzymes, the terpene synthases and the cytochrome P450-dependent monooxygenases of the CYP720B group. Extensive studies have been conducted on the genomics, proteomics and molecular biochemical characterization of these enzymes. Many of the conifer terpene synthases are multi-product enzymes, and the P450 enzymes of the CYP720B group are promiscuous in catalyzing multiple oxidations, along homologous series of diterpenoids, from a broad spectrum of substrates. The terpene synthases and CYP720B genes respond to authentic or simulated insect attack with increased transcript levels, protein abundance and enzyme activity. The constitutive and induced oleoresin terpenoids for conifer defense accumulate in preformed cortical resin ducts and in xylem trauma-associated resin ducts. Formation of these resin ducts de novo in the cambium zone and developing xylem, following insect attack or treatment of trees with methyl jasmonate, is a unique feature of the induced defense of long-lived conifer trees.

Conifer Woods of the Pliocene Age from Yunnan, China

Abstract: The Tertiary floras play an integral role in understanding the biodiversity and interactions between climate and vegetation in Yunnan, China. The fossil spores, pollen grains, and leaves in this region have been investiaged intensively. In comparison, the woods have been studied relatively little. A large number of Pliocene wood specimens was collected from the opencast lignite coal mine of Hongxing situated in Changning County of Yunnan Province. Among the collection, Tsuga cf. dumosa (D. Don) Eichler and Pinus cf. armandii Franchet were identified based on wood structures. The subtle feature of tori extensions is reported in the wood of T. cf. dumosa. Considering the climatic requirements of modern T. dumosa and P. armandii, the two species of conifer described from Pliocene sediments probably grew in mountainous terrain at an elevation of approximately 2 300 m, in a cool and humid environment.

N and P resorption as functions of the needle age class in two conifer trees

Aims Given the importance of resorption in nutrient conservations,nu-trient resorption should change with leaf age if resorption depends on nutrient content,and if nutrient content changes with leaf age.However,no study has addressed this issue.Methods Here,we measured N and P concentrations of needles of different ages in two woody evergreen conifer species-white spruce(Picea glauca Voss.)and balsam fir(Abies balsamea Mill.)-to determine the effects of needle aging on nutrient resorption.Important Findings For both species,N and P concentrations were higher in newer needles than in older needles.Nutrient resorption efficiency,i.e.percentage of nutrients resorbed during senescence,also declined significantly with needle age from 73 to 22%in these two evergreen conifer species.The difference in nutrient resorp-tion between old and young needles may be attributed to the size of N and P sink tissues,which is likely to decrease with needle age.These results suggest that needle age affects the extent of N and P resorption in these two evergreen conifer species.

Germination and early seedling growth of Pinus densata Mast.provenances

We studied seed germination and early seedling growth of Pinus densata to explore the range of variability within the species and to inform afforestation practices. Phenotypes were evaluated at a forest tree nursery under conditions that support Pinus yunnanensis, one of the presumed parental species of P. densata. Seeds were col- lected from 20 open-pollinated trees within each of eight autochthonous populations representing the natural distri- bution of P. densata in China to assess variation in ger- mination traits and early seedling growth, and to examine the relationships among these traits. Results showed that seeds from all populations germinated and seedlings established successfully. There were significant differences among populations in 13 of 14 traits evaluated. Seed germination and early seedling growth were strongly related to seed size and seed weight. Bigger seeds germi- nated earlier and faster than small seeds, and seedling size was positively correlated with seed size. Some germination traits were strongly and significantly correlated with cli- matic variables associated with the provenance of the studied populations. Based on these observations, we conclude there were large, significant, and biologically important differences among P. densata populations in seed germination and seedling growth traits. The observed variability probably reflects a high degree of adaptive dif- ferentiation among populations that is likely to be relevant for future afforestation.

Siberian silkmoth outbreaks surpassed geoclimatic barrier in Siberian Mountains

Siberian silkmoth(SSM,Dendrolimus sibiricus Tschetv.)is the most important defoliator of Siberian pine(Pinus sibirica Du Tour)and fir(Abies sibirica Ledeb.)stands.Warming-induced SSM outbreaks are one of the major driving factors of successions within the taiga zone.It is suggested that climate change impacted the SSM range and life cycle.We analyzed the migration of alpine and northerly SSM outbreak boundaries in Siberia and the impact of the climate variables and topography on the outbreak dynamics.We used time-series scenes(multispectral data,and vegetation indexes EVI and NDII)in combination with field studies,climate variables,and GIS techniques.We found that SSM outbreaks in the area of alpine boundary shifted about 370 m uphill since the mid of 1950.The outbreak onset was promoted by increased dryness and active temperatures and decreased root zone moisture content in the spring-early summer period.The terrain topography strongly affected SSM outbreak onset and dynamics.Initially,the outbreak was located at the middle elevations on the gentle concave southeastern slopes,which are the favorable insect habitats between outbreaks.Then the outbreak expanded uphill and downhill,to steeper slopes,and both concave and convex terrains.Alongside with elevation range expansion,SSM surpassed its northern historical outbreak boundary:the potential outbreaks’boundary moved about 300 km northward.Climate warming contributes to SSM migration into former outbreak free conifer stands located in highlands and at northern latitudes.