Water-quenched copper-nickel metallurgical slag enriched with olivine minerals exhibits promising potential for the production of CO_(2)-mineralized cementitious materials.In this work,copper-nickel slag-based cementi...Water-quenched copper-nickel metallurgical slag enriched with olivine minerals exhibits promising potential for the production of CO_(2)-mineralized cementitious materials.In this work,copper-nickel slag-based cementitious material(CNCM)was synthesized by using different chemical activation methods to enhance its hydration reactivity and CO_(2) mineralization capacity.Different water curing ages and carbonation conditions were explored related to their carbonation and mechanical properties development.Meanwhile,thermogravimetry differential scanning calorimetry and X-ray diffraction methods were applied to evaluate the CO_(2) adsorption amount and carbonation products of CNCM.Microstructure development of carbonated CNCM blocks was examined by backscattered electron imaging(BSE)with energy-dispersive X-ray spectrometry.Results showed that among the studied samples,the CNCM sample that was subjected to water curing for 3 d exhibited the highest CO_(2) sequestration amount of 8.51wt%at 80℃and 72 h while presenting the compressive strength of 39.07 MPa.This result indicated that 1 t of this CNCM can sequester 85.1 kg of CO_(2) and exhibit high compressive strength.Although the addition of citric acid did not improve strength development,it was beneficial to increase the CO_(2) diffusion and adsorption amount under the same carbonation conditions from BSE results.This work provides guidance for synthesizing CO_(2)-mineralized cementitious materials using large amounts of metallurgical slags containing olivine minerals.展开更多
In our study we investigated a refractory copper-nickel sulfide ore separation by using a cyclonic-static micro-bubble flotation column (FCSMC). The process mineralogy of the main products was studied. Using a scannin...In our study we investigated a refractory copper-nickel sulfide ore separation by using a cyclonic-static micro-bubble flotation column (FCSMC). The process mineralogy of the main products was studied. Using a scanning electron microscope-energy dispersive system (SEM-EDS) and an X-ray spectrometer the mineral category and content of samples were analyzed. By using a mineral liberation analyzer (MLA) the mineral liberation characteristics were revealed. It is shown that in roughing feed the monomers liberation degree of nickel pyrite and chalcopyrite take up 84.11% and 88.82%, respectively. In tailings, the lost nickel pyrite and chalcopyrite are mainly monomers. Therefore, strengthening the micro-fine particle recovery capacity is the key to increase recovery.展开更多
The isothermal compression tests of C71500 copper-nickel alloy at different temperatures (1 073-1 273 K) and strain rates (0.01-10 s^-1) were carried out on Gleeble-3500 thermo-mechanical simulator.The real stress-str...The isothermal compression tests of C71500 copper-nickel alloy at different temperatures (1 073-1 273 K) and strain rates (0.01-10 s^-1) were carried out on Gleeble-3500 thermo-mechanical simulator.The real stress-strain data were obtained.On the basis of dynamic material model,the power dissipation was established.The peak efficiency of the power dissipation is 57%.At the same time,Prasad’s,Murty’s and Babu’s instability criteria based on Ziegler’s expectant rheology theory,and Gegel’s and Malas’s instability criteria based on Lyaponov’s function theory,were used to predict the unstable regions in the processing map.The maximum entropy generation rate and large plastic deformation principle are more in line with the hot deformation process of C71500 alloy,so the accuracy of Prasad’s instability criterion is much better.According to the obtained macro-crack and micro-metallographic structure morphologies,the temperature range of 1 098-1 156 K and the strain rate range of 2.91-10 s^-1,and the temperature range of 1 171-1 273 K and the strain rate range of 0.01-0.33 s^-1 are more suitable for the processing area of C71500 alloy.The accuracy of the above conclusions were verified by the forging of materials and the analysis of hot piercing tubes.The significance of this paper is to provide theoretical basis and technological conditions for hot-press processing of C71500 alloy.展开更多
The Beishan rift zone in Xinjiang Uygur Autonomous Region was formed due to strong activities of faults on the basement of the Tarim continental crust.Despite the fact that many geological research results of the rift...The Beishan rift zone in Xinjiang Uygur Autonomous Region was formed due to strong activities of faults on the basement of the Tarim continental crust.Despite the fact that many geological research results of the rift zone have been achieved,only a few studies have been conducted on its regional geophysical characteristics.In this paper,the gravity and magnetic anomalies of the rift zone were highlighted through specific data processing of 1∶50000 high-precision aeromagnetic data and gravity data with a grid spacing of 2 km×2 km.Based on this,the geophysical evidence for the scope and internal structures of the Beishan rift zone was obtained for the first time.The distinct characteristics of magnetic and gravity fields in the areas to the north and south of the Beishan rift zone reveal that deep faults exist between the Beishan rift zone and the geological units on the southern and northern sides.Furthermore,the faults on the two areas contain the bidirectional thrusts and have flower-shaped structures according to the characteristics of the magnetic and gravity fields.The Beishan rift zone can be divided into two tectonomagmatic zones,namely the Zhongposhan-Bijiashan-Cihai-Baishanliang zone(the northern zone)and the Bayiquan-Qixin-Baishan zone(the southern zone).The northern zone can be further subdivided into three comet-shaped anomaly groups(tectonomagmatic areas),while the southern zone can be further subdivided into two tectonomagmatic areas.According to the characteristics of aeromagnetic anomalies and gravity field,19 mafic-ultramafic complexes were delineated.The known Pobei,Hongshishan,and Qixin complexes are all located within the inferred complexes,with estimates of total explored resources of Ni,Cu,and Au of 3×10^(6) t,10×10^(3) t and 10 t,respectively.The prospecting of high-grade copper-nickel deposits should focus on the periphery and deep parts of the known and inferred mafic-ultramafic complexes.Among them,the peripheral strata of the complexes specifically have great prospecting potential of large-scale high-grade copper-nickel deposits of magma injection type.Finally,this paper analyzed the application effects of the rapid airborne-ground-drilling synergetic exploration method in the prospecting of copper-nickel deposits in Qixin,Beishan,Xinjiang,which will provide references for further exploration of copper-nickel deposits in Beishan area,Xinjiang.展开更多
This paper obtains the lowest-energy geometric structures and the electronic and magnetic properties of small CuNiN clusters by using all-electron density functional theory. The calculated results reveal that the Cu a...This paper obtains the lowest-energy geometric structures and the electronic and magnetic properties of small CuNiN clusters by using all-electron density functional theory. The calculated results reveal that the Cu atom prefers to occupy the apical site when N ≤ 9 and for the clusters with N = 10, the Cu atom starts to encapsulate in the cage. The CuNi7 and CuNi9 are magic clusters. The magnetism correlates closely with the symmetry of the clusters. For these clusters, the charge tends to transfer from the nickel atoms to the copper atoms. It finds that the doping of Cu atom decreases the stability of pure NiN clusters.展开更多
The effect of 3-methyl 4-amino 1,2,4 triazole (MATA) on the corrosion behaviour of copper-nickel 70 - 30 (Monel) in NaCl 3% solution is investigated at 298 K by weight loss measurements, potentiodynamic polarisation a...The effect of 3-methyl 4-amino 1,2,4 triazole (MATA) on the corrosion behaviour of copper-nickel 70 - 30 (Monel) in NaCl 3% solution is investigated at 298 K by weight loss measurements, potentiodynamic polarisation and impedance spectroscopy (EIS′) methods. Preliminary screening of the inhibition efficiency (ECR) was carried out with using weight- loss measurements. Polarization measurements showed that the organic compound investigated is mixed type inhibitor (it acts on the cathodic and the cathodic reactions), inhibiting the corrosion of Monel by blocking the active sites of the metal surface. Changes in the impedance parameters charge transfer resistance (Rct) and double layer capacitance (Cdl) are related to adsorption of organic inhibitor of the metal surface, leading to the formation of protective film, which grows with increasing exposure time. Inhibition efficiencies obtained from cathodic Tafel plots, gravimetric and EIS methods are in good agreement. Results obtained shows that the (MATA) is good inhibitor for copper – nickel, and its efficiency reaches more than 95% at 60 ppm after 30 mn of immersion.展开更多
The characteristics of previously determined and a number of new,unknown before,mineral phases are presented.On this area in sulphide ores of the Central the Pai-Khoi dolerite bodies.In the process of intrusion format...The characteristics of previously determined and a number of new,unknown before,mineral phases are presented.On this area in sulphide ores of the Central the Pai-Khoi dolerite bodies.In the process of intrusion formation and sulphidic magma crystallization the subtraction of such elements as lead, stibium,cobalt,arsenic,and accordingly migration and concentration of minerals of platinum展开更多
In the early 1980's, the author proposed his view that copper-nickel sulphide deposts are of ore magma origin. For more than ten years, this view has aroused attention of his colleagues at home and abroad. In this...In the early 1980's, the author proposed his view that copper-nickel sulphide deposts are of ore magma origin. For more than ten years, this view has aroused attention of his colleagues at home and abroad. In this paper an attempt is made to deal with the genetic model for ore magma of copper-nickel sulphide deposits in more details on the basis of geological, geochemical, petrophysico - chemical and thermodynamic studies of the Chibaisong copper-nickel sulphide deposit in the Changbai Mountains, Jilin province.展开更多
The platinum-group element geochemistry of rocks and ores from Jinchuan super-large copper-nickel sulfide deposit is systemically studied in this paper. The Cu/Pd mean ratio of Jinchuan intrusion is lower than that of...The platinum-group element geochemistry of rocks and ores from Jinchuan super-large copper-nickel sulfide deposit is systemically studied in this paper. The Cu/Pd mean ratio of Jinchuan intrusion is lower than that of original mantle magma, which indicates that these ultrabasic rocks were crystallized from magma that lost Pd in the form of melting segregation of sulfides. The PGE of the rocks show trend of partial melting, similar to that of mantle peridotite, which shows that magma formation occurs during rock-forming and ore-forming processes. The chondrite normalized PGE patterns of the rocks and ores are well related to each other, which signifies the signatures of multi-episode magmatic intrusion, melting and differentiation in the formation processes of rocks and ores. In addition, analyses about the relation between PGE and S, and study on Re-Os isotopes indicate that few contamination of the crustal substances occurred during the magmatic intrusion and the formation of deposit. However, contamination by crustal substances helps to supply part of the S for the enrichment of PGE. Meanwhile, the hydrothermal process is also advantageous for the enrichment of PGE, especially lbr Pt and Pd, due to deep melting segregation. The characteristic parameters (such as Pt/(Pt+Pd), (Pt+Pd)/(Ru+Ir+Os), Pd/Ir, Cu/(Ni+Cu), and so on.) for platinum-group elements for Jinchuan sulfide copper-nickel deposit show the same features as those for sulfide copper-nickel deposit related to basic magma, which also illustrates its original magma property representative of Mg-high tholeiite. Therefore, it is the marie (not ultramafic) magma that resulted in the formation of the superlarge sulfide copper-nickel deposit enriched in Cu and PGE. To sum up, the geochemical characteristics of platinum-group elements in rocks and ores from Jinchuan copper-nickel sulfide deposit are constrained by the continental rift tectonic environment, the parent magma features, the enriched mantel magma source, the complex metallogenesis and PGE geochemical signatures, and this would be rather significant for the study about the genetic mechanism of copper-nickel sulfide deposits.展开更多
Based on horizontal continuous casting with a heating-cooling combined mold (HCCM) technology, this article investigated the effects of processing parameters on the liquid-solid interface (LSI) position and the in...Based on horizontal continuous casting with a heating-cooling combined mold (HCCM) technology, this article investigated the effects of processing parameters on the liquid-solid interface (LSI) position and the influence of LSI position on the surface quality, microstructure, texture, and mechanical properties of a BFe10-1-1 tube (φ50 mm × 5 mm). HCCM efficiently improves the temperature gradient in front of the LSI. Through controlling the LSI position, the radial columnar-grained microstructure that is commonly generated by cooling mold casting can be eliminated, and the axial columnar-grained microstructure can be obtained. Under the condition of 1250℃ melting and holding temperature, 1200-1250℃ mold heating temperature, 50-80 mm/min mean drawing speed, and 500-700 L/h cooling water flow rate, the LSI position is located at the middle of the transition zone or near the entrance of the cooling section, and the as-cast tube not only has a strong axial columnar-grained microstructure ({hkl}〈621〉, {hkl}〈221〉) due to strong axial heating conduction during solidification but also has smooth internal and external surfaces without cracks, scratches, and other macroscopic defects due to short solidified shell length and short contact length between the tube and the mold at high temperature. The elongation and tensile strength of the tube are 46.0%-47.2% and 210-221 MPa, respectively, which can be directly used for the subsequent cold-large-strain processing.展开更多
The Xingdi mafic-ultramafic intrusions occur in the northeastern margin of the Tarim craton. The Xingdi No. 3 intrusion is the smallest of four intrusions, with an exposed area of 1.7 km2, and the zircon U-Pb age of t...The Xingdi mafic-ultramafic intrusions occur in the northeastern margin of the Tarim craton. The Xingdi No. 3 intrusion is the smallest of four intrusions, with an exposed area of 1.7 km2, and the zircon U-Pb age of the intrusion is 752±4 Ma. The intrusion consists of gabbros, pyroxenites and peridotites, and exhibits a crystallization sequence of the main rock-forming minerals as olivine, orthopyroxene, clinopyroxene and plagioclase. Mineralization occurred at or near the boundaries of the intrusion between pyroxenites and peridotites, and appears as a layered or lenticular shape about 500 m long and 4–15 m wide. The primary sulfides have a relatively simple mineralogy dominated by pyrrhotite-pentlandite-chalcopyrite assemblages, which occur as droplet, star-like and graphic texture and locally sideronitic structures. Geochronological and geochemistry investigations suggest that the Xingdi mafic-ultramafic intrusions and coeval volcanic rock in the Kuluktag area of the Tarim craton formed in an intracontinental breakup environment. Based on the composition of the dominant rockforming minerals and covariant relationships of other oxides versus Mg O, the parental magma of the Xingdi No.3 intrusion belongs to high-Mg tholeiitic basaltic magmas with Mg O of 10.78 wt%. The Xingdi No.3 intrusive rocks are characterized by light REE enrichment relative to heavy REE, negative Nb-Ta anomalies, low 143Nd/144Nd ratios(from 0.511183 to 0.511793) and high initial 87Sr/86Sr ratios(from 0.7051 to 0.7113). The magma was derived from the enriched-lithospheric mantle and was contaminated during emplacement. According to rock assemblages, mineralization, olivine characteristics, geochemical characteristics and mass balance, there are better copper-nickel ore prospects in the Xingdi No.3 intrusion than in the other three intrusions in the area.展开更多
The bimetallic nanoparticles compositing of Ni-rich core and Cu-rich shell(Ni/Cu NPs)were successfully synthesized by a liquid-phase thermal decomposition method.The content of copper and nickel in Ni/Cu NPs was contr...The bimetallic nanoparticles compositing of Ni-rich core and Cu-rich shell(Ni/Cu NPs)were successfully synthesized by a liquid-phase thermal decomposition method.The content of copper and nickel in Ni/Cu NPs was controllable by adjusting the ratio of two metal precursors,copper formate(Cuf)and nickel acetate tetrahydrate(Ni(OAc)_(2)·4H_(2)O).Ni/Cu NPs were further anchored on graphene oxide(GO)to prepare a magnetic composite catalyst,called Ni/Cu-GO.The dispersibility of Ni/Cu NPs in solution was enhanced by GO anchoring to prevent the sintering and aggregation during the reaction process,thereby ensuring the catalytic and cycling performance of the catalyst.The catalytic transfer hydrogenation(CTH)reaction of nitroaromatics was investigated when ammonia borane was used as the hydrogen source.Cu dominated the main catalytic role in the reaction,while Ni played a synergistic role of catalysis and providing magnetic properties for separation.The Ni_(7)/Cu_(3)-GO catalyst exhibited the best catalytic performance with the conversion and yield of 99%and 96%,respectively,when 2-methyl-5-nitrophenol was used as the substrate.The Ni_(7)/Cu_(3)-GO catalyst also exhibited excellent cyclic catalytic performance with the 5-amino-2-methylphenol yield of above 90%after six cycles.In addition,the Ni_(7)/Cu_(3)-GO catalyst could be quickly recycled by magnetic separation.Moreover,the Ni_(7)/Cu_(3)-GO catalyst showed good catalytic performance for halogen-containing nitroaromatics without dehalogenation.展开更多
A complicated Cu-Ni based alloy was developed to fabricate wear-resisting bush for high temperature application.The concern focuses on the control of equiaxed grains in the developed alloy ingot prepared by centrifuga...A complicated Cu-Ni based alloy was developed to fabricate wear-resisting bush for high temperature application.The concern focuses on the control of equiaxed grains in the developed alloy ingot prepared by centrifugal casting.The results show that the equiaxed grains are determined by the pouring temperature of the melt,the cooling rate and the rotation speed of the mold.With the decrease in pouring temperature,the fraction of the equiaxed grains in the transverse section of the ingot increases and the average length of columnar grain decreases.When the pouring temperature is confined below 1,250℃,complete equiaxed grains can be obtained.Based on the optimal centrifugal casting processing,the tensile strength of the developed alloy ingot with complete equiaxed grains reaches to 810 MPa and 435 MPa at room temperature and 500℃,respectively,which is 14% and 110% higher than that of common commercial QAl10-4-4 alloy.The wear rate of the developed alloy is 7.0 × 10-8 and 3.8 × 10-7 mm3?N-1?mm-1 at room temperature and 500℃,respectively,which is 5 times and 39 times lower than that of QAl10-4-4 alloy.展开更多
After Cu-Ni ore powder pre-soaked in AlCl<sub>3</sub> solution.the leaching ratios of copper andnickel can increase obviously.By X-ray diffraction analyses,electron energy spectrum analysesand electrochemi...After Cu-Ni ore powder pre-soaked in AlCl<sub>3</sub> solution.the leaching ratios of copper andnickel can increase obviously.By X-ray diffraction analyses,electron energy spectrum analysesand electrochemical experiments,it is affirmed that,the activation of aluminum ion includestwo aspects:one is the surface change of the ore by the absorption of hydrolysates,and the oth-er is the change of semiconductor characteristics of the metal sulfides by impurity aluminum ionentering the lattice,so that leaching reactions are accelerated.展开更多
Precursor (Metal-organic decomposition (MOD)) inks are used to fabricate 2D and 3D printed conductive structures directly onto a substrate. By formulating a nanoalloy structure containing multiple metals, the opportun...Precursor (Metal-organic decomposition (MOD)) inks are used to fabricate 2D and 3D printed conductive structures directly onto a substrate. By formulating a nanoalloy structure containing multiple metals, the opportunity to modify chemical and physical properties exists. In this paper, a copper-nickel bimetallic nanoalloy film was fabricated by mixing copper and nickel precursor inks and sintering them in vacuum. The individual elemental inks were formulated and characterized using SEM, EDS, and XRD. During thermal processing, elemental copper forms first and is followed by the formation of bimetallic copper-nickel alloy. The encapsulation of the underlying copper by the nickel-rich alloy provides excellent oxidation resistance. No change in film resistance was observed after the film was exposed to an oxygen plasma. Nanoalloy films printed using reactive metallic inks have a variety of important applications involving local control of alloy composition. Examples include facile formation of layered nanostructures, and electrical conductivity with oxidative stability.展开更多
Re-Os dating on copper-nickel sulfide ores from the Baotan area, Guangxi, yielded an ore-forming age of 982±21 Ma(2σ), which demonstrates that copper-nickel sulfide deposits and their related mafic-ultramafic ro...Re-Os dating on copper-nickel sulfide ores from the Baotan area, Guangxi, yielded an ore-forming age of 982±21 Ma(2σ), which demonstrates that copper-nickel sulfide deposits and their related mafic-ultramafic rocks occurred in the same period of time with the ophiolites in northeastern Jiangxi. Both of them are the products of collision-convergence between the Cathaysian plate and Yangtze plate and the subsequent extensional environment. Calculation of the γOs of the 982 Ma copper-nickel sulfide ores and its correlation with Re/Os indicate that injection-type massive ores display lower γOs values(-15.6 to -8.2) and lower Re/Os ratios(0.32 to 0.43), while basal liquation-type ores have γOs= -27.9 to -7.3 and Re/Os=5.36 to 11.24. This suggests that these copper-nickel sulfide ores and their related mafic-ultramafic rocks were derived from a Re-depleted mantle source and that contamination with some crustal material occurred during their intrusion.展开更多
Ammonia(NH_(3))synthesis via electrocatalytic nitrogen reduction generally suffers from low NH_(3)yield and faradaic efficiency.Compared with activating stable,low-solubility N_(2),the electrochemical conversion of ni...Ammonia(NH_(3))synthesis via electrocatalytic nitrogen reduction generally suffers from low NH_(3)yield and faradaic efficiency.Compared with activating stable,low-solubility N_(2),the electrochemical conversion of nitrates to ammonia provides a more reasonable route for NH_(3)production.Herein,we introduce Ar-plasma to enhance the interaction between copper-nickel alloys and carbon substrate to improve the performance of NH_(3)production.The NH_(3)faradaic efficiency from nitrate is nearly 100%and the yield rate is over 6000μgNH_(3)cm^(−2)h^(−1).DFT(density functional theory)calculation reveals the high performance of Cu_(50)Ni_(50)originates from the lower energy barrier on the reaction path and the closer position to the Fermi level of the d-band center.This work offers a promising strategy for plasma-modified electrocatalyst to promote ammonia synthesis via nitrate reduction.展开更多
High-performance supercapacitors require electrodes featuring a high surface area,suitable porosity,and conductivity.Metal-organic frameworks(MOFs)hold a high surface area and suitable porosity while insufficient cond...High-performance supercapacitors require electrodes featuring a high surface area,suitable porosity,and conductivity.Metal-organic frameworks(MOFs)hold a high surface area and suitable porosity while insufficient conductivity.Herein,a single-step chemical strategy was developed to directly synthesize a composite of copper-nickel rubeanate MOF and highly conductive reduced graphene oxide(rGO)nanosheets(CNRG-MOF)on nickel foam(CNRG-MOF/NF)electrode.The nanocomposite enables it to use as a high-performance supercapacitor electrode.The bimetallic CNRG-MOF/NF electrode exhibits su-perior electrochemical performance than its single metallic counterparts.The optimized CNRG-MOF/NF electrode represents a high specific capacitance of 846.15 F g1 at a current density of 1.0 A g1.A three-electrode system exhibited up to 96.37%capacitance retention after 7000 galvanostatic charge-discharge(GCD)cycles,indicating its excellent stability.These results may pave the way for the direct use of MOF materials for electrochemical energy devices instead of pyrolyzing the MOFs to improve the conductivity while losing controllable structural merits.GCD curve was obtained at different current densities to evaluate the nanocomposite's asymmetric setup charge storage capability.The electrode capacity for the asymmetric system was measured as 93.3 F g1,which proves the capacitive property of CNRG-MOF/NF electrode.展开更多
The composition and structural evolution of the corrosion product film of two commercial 90Cu-10Ni tubes, namely TubeA and Tube B, after being immersed in natural seawater for 1, 3, and 6 months were characterized by ...The composition and structural evolution of the corrosion product film of two commercial 90Cu-10Ni tubes, namely TubeA and Tube B, after being immersed in natural seawater for 1, 3, and 6 months were characterized by scanning electronmicroscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy, and its effecton the erosion--corrosion behavior of the tubes was determined through a rotating cylinder electrode system using variouselectrochemical techniques. For the freshly polished samples used as contrast samples, the flow velocity mainly enhancedthe cathodic reaction at low flow velocities while both the anodic and the cathodic reactions were remarkably accelerated athigher flow velocities. The corrosion product films formed on the two commercial 90Cu-10Ni tubes after being immersedin seawater for up to 6 months are of a complex three-layer or multilayer structure. The structural evolution of the films isout of sync for the two tubes. A continuous residual substrate layer depleted of Ni was observed in the inner layer of thefilms on Tube B after 30, 90, and 180 days' immersion, while it was observed in the film on Tube A only after 180 days'immersion. The nature of the inner layer plays a crucial role in the erosion-corrosion resistance of the 90Cu-10Ni tubes athigher flow velocity. The film with a compact and continuous inner layer of Cu20 doped with Ni2+ and Ni3+ which bondsfirmly with the substrate could survive and even get repaired with the increased flow velocity. The film on Tube Bpossessing a hollow and discontinuous inner layer composed of the residual substrate was degraded rapidly with increasingrotation speed in spite of its quite good resistance at the stagnant or lower speed conditions.展开更多
Env ironmental pollution is currently identified as one of the major drivers of rapid decline of insect populations,and this finding has revitalized interest in insect responses to pollution.We tested the hypothesis t...Env ironmental pollution is currently identified as one of the major drivers of rapid decline of insect populations,and this finding has revitalized interest in insect responses to pollution.We tested the hypothesis that the pollution-induced decline of insect populations can be predicted from phenotypic stress responses expressed as morphological differences between populations inhabiting polluted and unpolluted sites.We explored populations of the brassy tortrix Eulia ministrana in subarctic forests along an environmental disturbance gradient created by long-lasting severe impacts of aerial emissions of the copper-nickel smelter in Monchegorsk,northwestern Russia.We used pheromone traps to measure the population densities of this leafrolling moth and to collect specimens for assessment of three morphological stress indices:size,forewing melanization,and fluctuating asymmetry in wing venation.Wing length of E.ministrana increased by 10%,and neither forewing melanization nor fluctuating asymmetry changed from the unpolluted forest to the heavily polluted industrial barren.However,the population density of E.ministrana decreased 5 to 10 fold in the same pollution gradient.Thus,none of the studied potential morphological stress indicators signaled vulnerability of E.ministrana to environmental pollution and/or to pollution-induced environmental disturbance.We conclude that insect populations can decline without any visible signs of stress.The use of morphological proxies of insect fitness to predict the consequences of human impact on insect populations is therefore risky until causal relationships between these proxies and insect abundance are deciphered.展开更多
基金supported by the Intergovernmental International Science and Technology Innovation Cooperation Key Project of the National Key Research and Development Program of China (No.2022YFE0135100)the National Natural Science Foundation of China (No.52072171)+1 种基金the Beijing Nova Program (No.20220484057)the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD).
文摘Water-quenched copper-nickel metallurgical slag enriched with olivine minerals exhibits promising potential for the production of CO_(2)-mineralized cementitious materials.In this work,copper-nickel slag-based cementitious material(CNCM)was synthesized by using different chemical activation methods to enhance its hydration reactivity and CO_(2) mineralization capacity.Different water curing ages and carbonation conditions were explored related to their carbonation and mechanical properties development.Meanwhile,thermogravimetry differential scanning calorimetry and X-ray diffraction methods were applied to evaluate the CO_(2) adsorption amount and carbonation products of CNCM.Microstructure development of carbonated CNCM blocks was examined by backscattered electron imaging(BSE)with energy-dispersive X-ray spectrometry.Results showed that among the studied samples,the CNCM sample that was subjected to water curing for 3 d exhibited the highest CO_(2) sequestration amount of 8.51wt%at 80℃and 72 h while presenting the compressive strength of 39.07 MPa.This result indicated that 1 t of this CNCM can sequester 85.1 kg of CO_(2) and exhibit high compressive strength.Although the addition of citric acid did not improve strength development,it was beneficial to increase the CO_(2) diffusion and adsorption amount under the same carbonation conditions from BSE results.This work provides guidance for synthesizing CO_(2)-mineralized cementitious materials using large amounts of metallurgical slags containing olivine minerals.
基金Projects 2008BAB31B01 supported by the National Key Technology R&D Program in the 11th Five-Year Plan of China50834006 by the National Natural Science Foundation of China
文摘In our study we investigated a refractory copper-nickel sulfide ore separation by using a cyclonic-static micro-bubble flotation column (FCSMC). The process mineralogy of the main products was studied. Using a scanning electron microscope-energy dispersive system (SEM-EDS) and an X-ray spectrometer the mineral category and content of samples were analyzed. By using a mineral liberation analyzer (MLA) the mineral liberation characteristics were revealed. It is shown that in roughing feed the monomers liberation degree of nickel pyrite and chalcopyrite take up 84.11% and 88.82%, respectively. In tailings, the lost nickel pyrite and chalcopyrite are mainly monomers. Therefore, strengthening the micro-fine particle recovery capacity is the key to increase recovery.
基金Funded by the National Natural Science Foundation of China(No.51801149)the Ministry of Industry and Information Technology of the People’s Republic of China(TC170A2KN-8)。
文摘The isothermal compression tests of C71500 copper-nickel alloy at different temperatures (1 073-1 273 K) and strain rates (0.01-10 s^-1) were carried out on Gleeble-3500 thermo-mechanical simulator.The real stress-strain data were obtained.On the basis of dynamic material model,the power dissipation was established.The peak efficiency of the power dissipation is 57%.At the same time,Prasad’s,Murty’s and Babu’s instability criteria based on Ziegler’s expectant rheology theory,and Gegel’s and Malas’s instability criteria based on Lyaponov’s function theory,were used to predict the unstable regions in the processing map.The maximum entropy generation rate and large plastic deformation principle are more in line with the hot deformation process of C71500 alloy,so the accuracy of Prasad’s instability criterion is much better.According to the obtained macro-crack and micro-metallographic structure morphologies,the temperature range of 1 098-1 156 K and the strain rate range of 2.91-10 s^-1,and the temperature range of 1 171-1 273 K and the strain rate range of 0.01-0.33 s^-1 are more suitable for the processing area of C71500 alloy.The accuracy of the above conclusions were verified by the forging of materials and the analysis of hot piercing tubes.The significance of this paper is to provide theoretical basis and technological conditions for hot-press processing of C71500 alloy.
基金supported by the National Key Research and Development Program of China(2017YFC0602206)the projects of the China Geological Survey(DD20160066,DD20190551).
文摘The Beishan rift zone in Xinjiang Uygur Autonomous Region was formed due to strong activities of faults on the basement of the Tarim continental crust.Despite the fact that many geological research results of the rift zone have been achieved,only a few studies have been conducted on its regional geophysical characteristics.In this paper,the gravity and magnetic anomalies of the rift zone were highlighted through specific data processing of 1∶50000 high-precision aeromagnetic data and gravity data with a grid spacing of 2 km×2 km.Based on this,the geophysical evidence for the scope and internal structures of the Beishan rift zone was obtained for the first time.The distinct characteristics of magnetic and gravity fields in the areas to the north and south of the Beishan rift zone reveal that deep faults exist between the Beishan rift zone and the geological units on the southern and northern sides.Furthermore,the faults on the two areas contain the bidirectional thrusts and have flower-shaped structures according to the characteristics of the magnetic and gravity fields.The Beishan rift zone can be divided into two tectonomagmatic zones,namely the Zhongposhan-Bijiashan-Cihai-Baishanliang zone(the northern zone)and the Bayiquan-Qixin-Baishan zone(the southern zone).The northern zone can be further subdivided into three comet-shaped anomaly groups(tectonomagmatic areas),while the southern zone can be further subdivided into two tectonomagmatic areas.According to the characteristics of aeromagnetic anomalies and gravity field,19 mafic-ultramafic complexes were delineated.The known Pobei,Hongshishan,and Qixin complexes are all located within the inferred complexes,with estimates of total explored resources of Ni,Cu,and Au of 3×10^(6) t,10×10^(3) t and 10 t,respectively.The prospecting of high-grade copper-nickel deposits should focus on the periphery and deep parts of the known and inferred mafic-ultramafic complexes.Among them,the peripheral strata of the complexes specifically have great prospecting potential of large-scale high-grade copper-nickel deposits of magma injection type.Finally,this paper analyzed the application effects of the rapid airborne-ground-drilling synergetic exploration method in the prospecting of copper-nickel deposits in Qixin,Beishan,Xinjiang,which will provide references for further exploration of copper-nickel deposits in Beishan area,Xinjiang.
文摘This paper obtains the lowest-energy geometric structures and the electronic and magnetic properties of small CuNiN clusters by using all-electron density functional theory. The calculated results reveal that the Cu atom prefers to occupy the apical site when N ≤ 9 and for the clusters with N = 10, the Cu atom starts to encapsulate in the cage. The CuNi7 and CuNi9 are magic clusters. The magnetism correlates closely with the symmetry of the clusters. For these clusters, the charge tends to transfer from the nickel atoms to the copper atoms. It finds that the doping of Cu atom decreases the stability of pure NiN clusters.
文摘The effect of 3-methyl 4-amino 1,2,4 triazole (MATA) on the corrosion behaviour of copper-nickel 70 - 30 (Monel) in NaCl 3% solution is investigated at 298 K by weight loss measurements, potentiodynamic polarisation and impedance spectroscopy (EIS′) methods. Preliminary screening of the inhibition efficiency (ECR) was carried out with using weight- loss measurements. Polarization measurements showed that the organic compound investigated is mixed type inhibitor (it acts on the cathodic and the cathodic reactions), inhibiting the corrosion of Monel by blocking the active sites of the metal surface. Changes in the impedance parameters charge transfer resistance (Rct) and double layer capacitance (Cdl) are related to adsorption of organic inhibitor of the metal surface, leading to the formation of protective film, which grows with increasing exposure time. Inhibition efficiencies obtained from cathodic Tafel plots, gravimetric and EIS methods are in good agreement. Results obtained shows that the (MATA) is good inhibitor for copper – nickel, and its efficiency reaches more than 95% at 60 ppm after 30 mn of immersion.
文摘The characteristics of previously determined and a number of new,unknown before,mineral phases are presented.On this area in sulphide ores of the Central the Pai-Khoi dolerite bodies.In the process of intrusion formation and sulphidic magma crystallization the subtraction of such elements as lead, stibium,cobalt,arsenic,and accordingly migration and concentration of minerals of platinum
文摘In the early 1980's, the author proposed his view that copper-nickel sulphide deposts are of ore magma origin. For more than ten years, this view has aroused attention of his colleagues at home and abroad. In this paper an attempt is made to deal with the genetic model for ore magma of copper-nickel sulphide deposits in more details on the basis of geological, geochemical, petrophysico - chemical and thermodynamic studies of the Chibaisong copper-nickel sulphide deposit in the Changbai Mountains, Jilin province.
文摘The platinum-group element geochemistry of rocks and ores from Jinchuan super-large copper-nickel sulfide deposit is systemically studied in this paper. The Cu/Pd mean ratio of Jinchuan intrusion is lower than that of original mantle magma, which indicates that these ultrabasic rocks were crystallized from magma that lost Pd in the form of melting segregation of sulfides. The PGE of the rocks show trend of partial melting, similar to that of mantle peridotite, which shows that magma formation occurs during rock-forming and ore-forming processes. The chondrite normalized PGE patterns of the rocks and ores are well related to each other, which signifies the signatures of multi-episode magmatic intrusion, melting and differentiation in the formation processes of rocks and ores. In addition, analyses about the relation between PGE and S, and study on Re-Os isotopes indicate that few contamination of the crustal substances occurred during the magmatic intrusion and the formation of deposit. However, contamination by crustal substances helps to supply part of the S for the enrichment of PGE. Meanwhile, the hydrothermal process is also advantageous for the enrichment of PGE, especially lbr Pt and Pd, due to deep melting segregation. The characteristic parameters (such as Pt/(Pt+Pd), (Pt+Pd)/(Ru+Ir+Os), Pd/Ir, Cu/(Ni+Cu), and so on.) for platinum-group elements for Jinchuan sulfide copper-nickel deposit show the same features as those for sulfide copper-nickel deposit related to basic magma, which also illustrates its original magma property representative of Mg-high tholeiite. Therefore, it is the marie (not ultramafic) magma that resulted in the formation of the superlarge sulfide copper-nickel deposit enriched in Cu and PGE. To sum up, the geochemical characteristics of platinum-group elements in rocks and ores from Jinchuan copper-nickel sulfide deposit are constrained by the continental rift tectonic environment, the parent magma features, the enriched mantel magma source, the complex metallogenesis and PGE geochemical signatures, and this would be rather significant for the study about the genetic mechanism of copper-nickel sulfide deposits.
基金financial support of National Key Technology R&D Program of China (No.2011BAE23B00)
文摘Based on horizontal continuous casting with a heating-cooling combined mold (HCCM) technology, this article investigated the effects of processing parameters on the liquid-solid interface (LSI) position and the influence of LSI position on the surface quality, microstructure, texture, and mechanical properties of a BFe10-1-1 tube (φ50 mm × 5 mm). HCCM efficiently improves the temperature gradient in front of the LSI. Through controlling the LSI position, the radial columnar-grained microstructure that is commonly generated by cooling mold casting can be eliminated, and the axial columnar-grained microstructure can be obtained. Under the condition of 1250℃ melting and holding temperature, 1200-1250℃ mold heating temperature, 50-80 mm/min mean drawing speed, and 500-700 L/h cooling water flow rate, the LSI position is located at the middle of the transition zone or near the entrance of the cooling section, and the as-cast tube not only has a strong axial columnar-grained microstructure ({hkl}〈621〉, {hkl}〈221〉) due to strong axial heating conduction during solidification but also has smooth internal and external surfaces without cracks, scratches, and other macroscopic defects due to short solidified shell length and short contact length between the tube and the mold at high temperature. The elongation and tensile strength of the tube are 46.0%-47.2% and 210-221 MPa, respectively, which can be directly used for the subsequent cold-large-strain processing.
基金supported by the National Natural Science Foundation of China(Grant No.41302070)the Fundamental Research Funds for the Central Universities(310827173401,310827153407)China Regional Geological Survey(12120113043100)
文摘The Xingdi mafic-ultramafic intrusions occur in the northeastern margin of the Tarim craton. The Xingdi No. 3 intrusion is the smallest of four intrusions, with an exposed area of 1.7 km2, and the zircon U-Pb age of the intrusion is 752±4 Ma. The intrusion consists of gabbros, pyroxenites and peridotites, and exhibits a crystallization sequence of the main rock-forming minerals as olivine, orthopyroxene, clinopyroxene and plagioclase. Mineralization occurred at or near the boundaries of the intrusion between pyroxenites and peridotites, and appears as a layered or lenticular shape about 500 m long and 4–15 m wide. The primary sulfides have a relatively simple mineralogy dominated by pyrrhotite-pentlandite-chalcopyrite assemblages, which occur as droplet, star-like and graphic texture and locally sideronitic structures. Geochronological and geochemistry investigations suggest that the Xingdi mafic-ultramafic intrusions and coeval volcanic rock in the Kuluktag area of the Tarim craton formed in an intracontinental breakup environment. Based on the composition of the dominant rockforming minerals and covariant relationships of other oxides versus Mg O, the parental magma of the Xingdi No.3 intrusion belongs to high-Mg tholeiitic basaltic magmas with Mg O of 10.78 wt%. The Xingdi No.3 intrusive rocks are characterized by light REE enrichment relative to heavy REE, negative Nb-Ta anomalies, low 143Nd/144Nd ratios(from 0.511183 to 0.511793) and high initial 87Sr/86Sr ratios(from 0.7051 to 0.7113). The magma was derived from the enriched-lithospheric mantle and was contaminated during emplacement. According to rock assemblages, mineralization, olivine characteristics, geochemical characteristics and mass balance, there are better copper-nickel ore prospects in the Xingdi No.3 intrusion than in the other three intrusions in the area.
基金supported by the National Natural Science Foundation of China(Grant No.21776161)。
文摘The bimetallic nanoparticles compositing of Ni-rich core and Cu-rich shell(Ni/Cu NPs)were successfully synthesized by a liquid-phase thermal decomposition method.The content of copper and nickel in Ni/Cu NPs was controllable by adjusting the ratio of two metal precursors,copper formate(Cuf)and nickel acetate tetrahydrate(Ni(OAc)_(2)·4H_(2)O).Ni/Cu NPs were further anchored on graphene oxide(GO)to prepare a magnetic composite catalyst,called Ni/Cu-GO.The dispersibility of Ni/Cu NPs in solution was enhanced by GO anchoring to prevent the sintering and aggregation during the reaction process,thereby ensuring the catalytic and cycling performance of the catalyst.The catalytic transfer hydrogenation(CTH)reaction of nitroaromatics was investigated when ammonia borane was used as the hydrogen source.Cu dominated the main catalytic role in the reaction,while Ni played a synergistic role of catalysis and providing magnetic properties for separation.The Ni_(7)/Cu_(3)-GO catalyst exhibited the best catalytic performance with the conversion and yield of 99%and 96%,respectively,when 2-methyl-5-nitrophenol was used as the substrate.The Ni_(7)/Cu_(3)-GO catalyst also exhibited excellent cyclic catalytic performance with the 5-amino-2-methylphenol yield of above 90%after six cycles.In addition,the Ni_(7)/Cu_(3)-GO catalyst could be quickly recycled by magnetic separation.Moreover,the Ni_(7)/Cu_(3)-GO catalyst showed good catalytic performance for halogen-containing nitroaromatics without dehalogenation.
文摘A complicated Cu-Ni based alloy was developed to fabricate wear-resisting bush for high temperature application.The concern focuses on the control of equiaxed grains in the developed alloy ingot prepared by centrifugal casting.The results show that the equiaxed grains are determined by the pouring temperature of the melt,the cooling rate and the rotation speed of the mold.With the decrease in pouring temperature,the fraction of the equiaxed grains in the transverse section of the ingot increases and the average length of columnar grain decreases.When the pouring temperature is confined below 1,250℃,complete equiaxed grains can be obtained.Based on the optimal centrifugal casting processing,the tensile strength of the developed alloy ingot with complete equiaxed grains reaches to 810 MPa and 435 MPa at room temperature and 500℃,respectively,which is 14% and 110% higher than that of common commercial QAl10-4-4 alloy.The wear rate of the developed alloy is 7.0 × 10-8 and 3.8 × 10-7 mm3?N-1?mm-1 at room temperature and 500℃,respectively,which is 5 times and 39 times lower than that of QAl10-4-4 alloy.
基金Supported by the National Nature Science and the fund of Natione Educational Committee for doctor degree
文摘After Cu-Ni ore powder pre-soaked in AlCl<sub>3</sub> solution.the leaching ratios of copper andnickel can increase obviously.By X-ray diffraction analyses,electron energy spectrum analysesand electrochemical experiments,it is affirmed that,the activation of aluminum ion includestwo aspects:one is the surface change of the ore by the absorption of hydrolysates,and the oth-er is the change of semiconductor characteristics of the metal sulfides by impurity aluminum ionentering the lattice,so that leaching reactions are accelerated.
文摘Precursor (Metal-organic decomposition (MOD)) inks are used to fabricate 2D and 3D printed conductive structures directly onto a substrate. By formulating a nanoalloy structure containing multiple metals, the opportunity to modify chemical and physical properties exists. In this paper, a copper-nickel bimetallic nanoalloy film was fabricated by mixing copper and nickel precursor inks and sintering them in vacuum. The individual elemental inks were formulated and characterized using SEM, EDS, and XRD. During thermal processing, elemental copper forms first and is followed by the formation of bimetallic copper-nickel alloy. The encapsulation of the underlying copper by the nickel-rich alloy provides excellent oxidation resistance. No change in film resistance was observed after the film was exposed to an oxygen plasma. Nanoalloy films printed using reactive metallic inks have a variety of important applications involving local control of alloy composition. Examples include facile formation of layered nanostructures, and electrical conductivity with oxidative stability.
基金This study was performed as part of the State Key Fundamental Project (Grant No. 1999043216) the State Geological Survey Project Kl .4. We would like to express our sincere thanks to Ma Fujun and Yang Kaitai of No. 6 Geological Party of the Guangxi
文摘Re-Os dating on copper-nickel sulfide ores from the Baotan area, Guangxi, yielded an ore-forming age of 982±21 Ma(2σ), which demonstrates that copper-nickel sulfide deposits and their related mafic-ultramafic rocks occurred in the same period of time with the ophiolites in northeastern Jiangxi. Both of them are the products of collision-convergence between the Cathaysian plate and Yangtze plate and the subsequent extensional environment. Calculation of the γOs of the 982 Ma copper-nickel sulfide ores and its correlation with Re/Os indicate that injection-type massive ores display lower γOs values(-15.6 to -8.2) and lower Re/Os ratios(0.32 to 0.43), while basal liquation-type ores have γOs= -27.9 to -7.3 and Re/Os=5.36 to 11.24. This suggests that these copper-nickel sulfide ores and their related mafic-ultramafic rocks were derived from a Re-depleted mantle source and that contamination with some crustal material occurred during their intrusion.
基金supported by the National Natural Science Foundation of China(No.51976191)the State Key Laboratory of Clean Energy Utilization(No.ZJUCEU2021003),Ecological civilization project,Zhejiang University and the Fundamental Research Funds for the Central Universities.
文摘Ammonia(NH_(3))synthesis via electrocatalytic nitrogen reduction generally suffers from low NH_(3)yield and faradaic efficiency.Compared with activating stable,low-solubility N_(2),the electrochemical conversion of nitrates to ammonia provides a more reasonable route for NH_(3)production.Herein,we introduce Ar-plasma to enhance the interaction between copper-nickel alloys and carbon substrate to improve the performance of NH_(3)production.The NH_(3)faradaic efficiency from nitrate is nearly 100%and the yield rate is over 6000μgNH_(3)cm^(−2)h^(−1).DFT(density functional theory)calculation reveals the high performance of Cu_(50)Ni_(50)originates from the lower energy barrier on the reaction path and the closer position to the Fermi level of the d-band center.This work offers a promising strategy for plasma-modified electrocatalyst to promote ammonia synthesis via nitrate reduction.
基金The authors wish to thank Iran National Science Foundation,grant No.98012523,for supporting this work.
文摘High-performance supercapacitors require electrodes featuring a high surface area,suitable porosity,and conductivity.Metal-organic frameworks(MOFs)hold a high surface area and suitable porosity while insufficient conductivity.Herein,a single-step chemical strategy was developed to directly synthesize a composite of copper-nickel rubeanate MOF and highly conductive reduced graphene oxide(rGO)nanosheets(CNRG-MOF)on nickel foam(CNRG-MOF/NF)electrode.The nanocomposite enables it to use as a high-performance supercapacitor electrode.The bimetallic CNRG-MOF/NF electrode exhibits su-perior electrochemical performance than its single metallic counterparts.The optimized CNRG-MOF/NF electrode represents a high specific capacitance of 846.15 F g1 at a current density of 1.0 A g1.A three-electrode system exhibited up to 96.37%capacitance retention after 7000 galvanostatic charge-discharge(GCD)cycles,indicating its excellent stability.These results may pave the way for the direct use of MOF materials for electrochemical energy devices instead of pyrolyzing the MOFs to improve the conductivity while losing controllable structural merits.GCD curve was obtained at different current densities to evaluate the nanocomposite's asymmetric setup charge storage capability.The electrode capacity for the asymmetric system was measured as 93.3 F g1,which proves the capacitive property of CNRG-MOF/NF electrode.
基金supported by the National Natural Science Foundation of China(Grant No.51601200)the National Environmental Corrosion Platform(No.2005DKA10400)
文摘The composition and structural evolution of the corrosion product film of two commercial 90Cu-10Ni tubes, namely TubeA and Tube B, after being immersed in natural seawater for 1, 3, and 6 months were characterized by scanning electronmicroscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy, and its effecton the erosion--corrosion behavior of the tubes was determined through a rotating cylinder electrode system using variouselectrochemical techniques. For the freshly polished samples used as contrast samples, the flow velocity mainly enhancedthe cathodic reaction at low flow velocities while both the anodic and the cathodic reactions were remarkably accelerated athigher flow velocities. The corrosion product films formed on the two commercial 90Cu-10Ni tubes after being immersedin seawater for up to 6 months are of a complex three-layer or multilayer structure. The structural evolution of the films isout of sync for the two tubes. A continuous residual substrate layer depleted of Ni was observed in the inner layer of thefilms on Tube B after 30, 90, and 180 days' immersion, while it was observed in the film on Tube A only after 180 days'immersion. The nature of the inner layer plays a crucial role in the erosion-corrosion resistance of the 90Cu-10Ni tubes athigher flow velocity. The film with a compact and continuous inner layer of Cu20 doped with Ni2+ and Ni3+ which bondsfirmly with the substrate could survive and even get repaired with the increased flow velocity. The film on Tube Bpossessing a hollow and discontinuous inner layer composed of the residual substrate was degraded rapidly with increasingrotation speed in spite of its quite good resistance at the stagnant or lower speed conditions.
基金the Academy of Finland(projects 276671 and 311929).
文摘Env ironmental pollution is currently identified as one of the major drivers of rapid decline of insect populations,and this finding has revitalized interest in insect responses to pollution.We tested the hypothesis that the pollution-induced decline of insect populations can be predicted from phenotypic stress responses expressed as morphological differences between populations inhabiting polluted and unpolluted sites.We explored populations of the brassy tortrix Eulia ministrana in subarctic forests along an environmental disturbance gradient created by long-lasting severe impacts of aerial emissions of the copper-nickel smelter in Monchegorsk,northwestern Russia.We used pheromone traps to measure the population densities of this leafrolling moth and to collect specimens for assessment of three morphological stress indices:size,forewing melanization,and fluctuating asymmetry in wing venation.Wing length of E.ministrana increased by 10%,and neither forewing melanization nor fluctuating asymmetry changed from the unpolluted forest to the heavily polluted industrial barren.However,the population density of E.ministrana decreased 5 to 10 fold in the same pollution gradient.Thus,none of the studied potential morphological stress indicators signaled vulnerability of E.ministrana to environmental pollution and/or to pollution-induced environmental disturbance.We conclude that insect populations can decline without any visible signs of stress.The use of morphological proxies of insect fitness to predict the consequences of human impact on insect populations is therefore risky until causal relationships between these proxies and insect abundance are deciphered.