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BACKGROUND The corona virus disease 2019 (COVID-19) has been a pandemic for more than one year and estimated to affect the whole world in the near future. CASE SUMMARY Here we reported that one COVID-19 patient with vesicles was treated by bullectomy. The patient’s perioperative laboratory tests were analyzed. The pathological findings of bullectomy were described and compared with those of common bulla cases. CONCLUSION This patient with vesicles underwent bullectomy and had a poor prognosis. He showed diffuse alveolar damage and extensive necrosis in bullectomy specimen. We hope our report will be of interest for clinicians who will treat COVID-19 patients in the future.

A novel processing method called V-shaped variable thickness rolling (V-VTR), has proposed to produce rolled profiled strips (RPS) by combining numerical simulation with experiment. Purpose to find a design method for accurately calculating roll parameters, and produce RPS with large thickness ratio. The V-VTR is short-term process includes preforming, decreasing, flattening and final passes. The critical minimum angle of roll and its calculation formula are proposed to ensure that metal only flow in TD, and the correctness of this method is proved by simulation and experiment. The metal flow and stress–strain state of angle below and above the critical minimum angle are discussed. Finally, target RPS with thickness ratio of 2:1 is successfully produced for the first time.

Microstructure and mechanical properties in core of a carburizing 20CrNi2MoV bearing steel subjected to cryogenic treatment were investigated. Conventional treatment sample was quenched and tempered at 180 °C for 2 h. Cryogenic treatment samples were quenched, cryogenically treated at − 80 and − 196 °C for 4 h, slowly returned to room temperature and thereafter tempered at 180 °C for 2 h, and finally tempered at 180 °C for 2 h. The scanning electron microscope, electron backscattering diffraction, X-ray diffraction and transmission electron microscope were adopted for microstructure characterization. The results show that cryogenic treatment increases the fraction of high-angle grain boundaries and the precipitation of finely dispersed carbides in the matrix, decreases the volume fraction of inter-lath retained austenite, and hence improves the strength and hardness. Compared with the conventional treatment, the hardness, yield strength and ultimate tensile strength of the steel after cryogenic treatment are increased by 11.7%, 12.6% and 18.3%, respectively, while the impact energy is decreased by 9.8%.

The effects of two alloying elements, i.e., yttrium (Y) and zirconium (Zr), on the inclusion, microstructure, tensile property and impact toughness of reduced activation ferritic/martensitic (RAFM) steel are analyzed. The size and number of particles were determined by optical microscopy, and the particle types were examined by scanning electron microscopy. The size of ~ 20% and ~ 85% of the inclusions lied in the range of 0.5–1.0 μm and 0.5–3.0 μm, respectively. In Y- and Y–Zr-containing specimens, the density of the fine inclusions, with a size less than 0.5 μm, was found to be 1.06 × 1017 and 9.82 × 1016 m−3, respectively. All specimens were normalized at 1323 K for 30 min and tempered at 923 and 1023 K for 90 min, resulting in the formation of tempered martensite with M23C6 carbides and MX precipitates. Zr-containing RAFM steel tempered at 923 K formed M23C6 carbides and nano-sized carbides with Zr, conferring superior strength balance and impact toughness. The yield strength of alloy reached 695 MPa, and a low ductile–brittle transition temperature of 238 K was maintained.

Anti-lipopolysaccharide factors are a group of small proteins with broad spectrum antiviral property and antibacterial activity. Herein, we obtained the genomic sequence of the Procambarus clarkii anti-lipopolysaccharide factor (PcALF) gene by using polymerase chain reaction to investigate its expression pattern in various tissues and in the immune tissues (Hepatopancreas) following exposure to pathogens. The deduced protein of PcALF was conserved; it displayed the signal peptides and putative lipo-polysaccharide binding domain, particularly the two conserved cysteine amino acid residues at both ends of the domain. The recombinant protein of PcALF was successfully expressed in Escherichia coli and rabbit anti-PcALF polyclonal antibodies were prepared. The qRT-PCR analysis showed unequal distribution of PcALF transcript in the examined tissues, however the transcript level was greatest in hepatopancreas. The challenge with peptidoglycan (PGN), lipo-polysaccharide (LPS) and Poly I:C significantly enhanced expression level of PcALF in hepatopancreas when compared with the PBS control. RNA interference of PcALF affected the mRNA expression levels of immune-related genes. Taken together, our data suggested that PcALF is an inducible protein and could play a key biological role in the innate immune defense of P. clarkii.

The effect of martensite–austenite (M–A) constituents formed in thermo-mechanical controlled process on impact toughness of 20CrNi2MoV steel was investigated. The variation in fraction, size and morphology of M–A constituent and its effect on toughness under different cooling rates were carried out. The result shows that there was no significant change in the fraction of M–A constituent under different cooling rates, but the distribution and size of M–A constituent were greatly influenced by cooling rate, which consequently influenced toughness. The amount of large blocky M–A constituents decreased from 4.7 to 1.7%, while that of elongated M–A constituents increased from 3.8 to 8.6% with the cooling rate increasing from 7 to 26 °C/s, and the corresponding impact energy decreased from 132 to 84 J. The deterioration of impact toughness could be related to the increase in the elongated M–A constituents. The elongated M–A constituents existing along the prior austenite grain boundaries in samples of 26 °C/s could easily lead to the formation of cleavage crack, which then results in the lower crack initiation energy than that of low cooling rate samples.

Although soil fungi play a pivotal role in determining soil ecosystematic feedbacks to afforestation, there remains a big knowledge gap in the effects of afforestation on soil fungal communities, especially at a watershed scale. In this study, the variations of soil fungal diversity and community structures under afforestation were investigated in Nanliu River Basin, where paddy field and dry farmland were converted to eucalyptus plantation at an unprecedented speed. Spatial distance along the upper, middle and lower reaches of the Basin were also considered to analyze the dominant sources of the variations. The results demonstrated that eucalyptus afforestation had little effect on soil fungal diversity but could significantly influence fungal community structures. As paddy field and dry farmland converted to eucalyptus plantation, dominant fungal phylum shifted from Ascomycota to Ascomycota and Basidiomycota. Compared with afforestation from dry farmland, much bigger variation of fungal community structures was found in afforestation from paddy field. In addition, the significant change of fungal community structures exhibited in the upper reaches was from dry farmland, while presented in the middle reaches was from paddy field. However, afforestation comprised a larger source of variation than spatial distance within the soil fungal community structures, and Fusarium, Westerdykella,Zopfiella and Scleroderma were the most sensitive genera affected by afforestation. These results showed that afforestation did not always cause soil fungal diversity change and the heterogeneity of fungal community structures under afforestation was mainly controlled by original land use practices, while spatial distance partly decided the results.

Harderian gland (HG) plays an important role in the physiological adaptation to terrestrial life, however, the mechanisms underlying the changes in the structure and function of the HG during aging remain unclear. This study investigated autophagy and apoptosis in the HG of striped dwarf hamsters (Cricetulus barabensis) of different ages (sub-adult, adult and aged groups) in both males and females. The results showed that LC3II/LC3I and puncta of LC3 were significantly higher in adult and aged individuals than sub-adults, whereas P62 decreased with age. Bax/bcl2was the highest in sub-adults of male and female individuals. Caspase3 activity was the highest in sub-adults of male and female individuals, and the citrate synthase activity was highest in sub-adults of females. ATP synthase, citrate synthase, dynamin-related protein 1 and mitochondrial fission factor (Mff) were the highest in sub-adults of females. Peptidylglycine α-amidating monooxygenase were the highest in the aged group, and those of gonadotropin-releasing hormone was the highest in the adult group. LC3II/LC3I, P62, Drp1, Fis, and bax/bcl2 were higher in males than that in females. These results suggest that apoptosis mainly affects growth and development in the HG, whereas autophagy affects aging. The difference of the HG weight and mitochondrial function between sexes is mainly related to the apoptosis.

The characteristics of ions in irrigation water can be significantly different in response to the changes in the salinity gradient. The chemical and biological processes of soils which were irrigated with this kind of water would therefore, be remarkably influenced. Based on the field sampling data and utilizing the Structural Equation Model (SEM), this paper aims to investigate the ionic characteristics of irrigation water and evaluate their direct and indirect impacts on soil salt ions, nutrients and microbial metabolic activities. The present results demonstrated that the ionic components of irrigation water had a direct influence on the soil salt ions. In particular, the Na+ concentrations in irrigation water were not only seen to significantly increase the soil Na+ concentrations but also change the other soil ions' concentrations. The contents of soil total nitrogen (TN), available phosphorus (Pava) and available potassium (Kava) appeared to change slightly with the increase of water salinity and meanwhile, no significant impact was found from any of the ions present in the irrigation water. Although high concentrations of Na+, Cl−, SO42−, Mg2+ and Ca2+ in irrigation water significantly drove the reduction of the soil organic carbon (OC), the direct influences were actually relatively small in this respect, and it was the increase of soil salt ions that dominantly led this reduction. Irrigation water with high salinity contents could significantly restrain the soil microbial metabolic activities. In addition, high concentrations of SO42−, Mg2+, Cl−, Ca2+ and Na+ in irrigation water (accounting for about 11% of the total effects), increased concentrations of soil salt ions (i.e., 74%) and reduced contents of soil OC (i.e., 15%) all contributed to this restraint, which together were seen to affect the microbial processes under saline water irrigation. The present results revealed that the ionic effects of irrigation water on soil processes would be more complex than we currently understood, which should attract increasing concerns in the future.

The multi-objective optimization of the SmartCrown intermediate roll profile for a cold rolling mill was proposed in this paper in order to improve the strip flatness quality. A coupling model of roll profile and strip flatness was established, and the roll gap profile, roll gap crown adjustment range, rolls contact pressure, and strip flatness under different intermediate roll profile parameters were calculated based on the coupling model. The results showed that the roll gap crown adjustment range and rolls contact pressure difference increased with increasing roll profile parameters. The roll profile parameters were multi-optimized based on the non-dominated sorting genetic algorithm II (NSGA-II). The minimum rolls contact pressure difference and maximum roll gap crown adjustment range were taken as the objective function of multi-objective optimization. The optimal roll profile parameters were applied to a six-high five stand tandem cold rolling mills, which improved the flatness quality of the DP780 steel strip.

If the magnetic resonance coupling-based wireless power transmission system has multiple receivers, cross-coupling will occur between the transmitter and the receiver, resulting in the variation of transmission characteristics when compared with the case of a single receiver. To solve this problem, a mutual inductance coupling circuit model for double-relay and multi-load transmission system and a calculation model for mutual inductance between solenoid coils in the same plane have been built to study the transmission characteristics of the system through simulation and testing. The study results show that: the cross-coupling effect between the transmitter and the receiver will cause resonance frequency shift, or even lead to the variation of resonance frequency splitting characteristic; when compared with a single-load system, the multi-load system may increase in total transmission power and efficiency; generally, with the introduction of additional receivers, the receiving power and efficiency of the original loads will decrease; along with the increase in circuit spacing and the decrease in cross-coupling, the transmission characteristics will gradually regress to the state of a single-load system. In this article, the calculation model for mutual inductance is correct and the maximum relative error in these calculating examples is 5.28%.

Many factors affect the formation of lyotropic liquid crystals (LLCs) in the poly(p-phenylene terephthamide) (PPTA)/H2SO4 system. In this systematic work, we prove that the hydrogen bonding between PPTA and H2SO4 plays a very important role for the LLC formation by using a combination of several characterization methods. Texture features and transition temperatures of different phases owing to hydrogen bonding in the PPTA/H2SO4 system were obtained by using polarized light microscopy and differential scanning calorimetry. 13C NMR and FTIR spectroscopy were applied to investigate the chemical structures in different phases, especially the hydrogen bonding between PPTA and H2SO4. The effect of molecular weight on phase transition was also examined. Moreover, guest compounds such as H2O, CH3SO3H, and carbon nanotube added will destroy the hydrogen-bonding network in the PPTA/H2SO4 system, resulting in different phase behaviors. All these results demonstrate that hydrogen bonding between PPTA and H2SO4 is the key factor for the highly ordered arrangement of polymer chains in the LLC state that is a nematic phase.

Peroxiredoxin (Prx) family members play a key role in host defense against oxidative stress, and modulate immune responses following microbial infection. Here, we cloned and characterized Procambarus clarkii Prx4 (Peroxiredoxin 4) cDNA, a regulator of oxidative stress and its expression analysis upon lipopolysaccharide (LPS) and polyriboinosinic polyribocytidylic acid (Poly I:C) infection. The cDNA fragment of PcPrx4 was 744 bp in length, encoding a putative protein of 248 amino acid residues. Real-time quantitative reverse transcription-PCR (qRT-PCR) analysis showed that the PcPrx4 was expressed in all the examined tissues, and it was highest in the hepatopancreas followed by the hemocytes and gill. The challenge with LPS and Poly I:C significantly up-regulated the expression of PcPrx4 in hepatopancreas, hemocytes and gill when compared with the control. Recombinant PcPrx4 protein was used to investigate the antioxidant function in vitro by mixed-function oxidase assay. The results demonstrated a dose-dependent inhibition of DNA damage by rPcPrx4 protein. Altogether, our results imply that PcPrx4 is implicated in defense against microbial pathogens and oxidants in P. clarkii.

To obtain the high-temperature strength and toughness of the medium–high-temperature–pressure steel, the microstructure evolution and mechanical properties of Fe-2Cr-Mo-0.12C steel subjected to three different tempering temperatures after being normalized were investigated. The results show that the microstructure of the sample, tempered in the range 675-725 °C for 50 min, did not change dramatically, yet the martensite/austenite constituents decomposed, and the bainite lath merged together and transformed into polygonal ferrite. At the same time, the precipitate size increased with an increase in tempering temperature. With the increase in the tempering temperature from 675 to 725 °C, the impact absorbed energy of the Fe-2Cr-Mo-0.12C steel at −40 °C increased from 257 to 325 J, and the high-temperature yield strength decreased; however, the high-temperature ultimate tensile strength tempered at 700 °C was outstanding (422-571 MPa) at different tested temperatures. The variations of the properties were attributed to the decomposition of M/A constituents and the coarsening of the precipitates. Fe-2Cr-Mo-0.12C steel normalized at 930 °C and tempered at 700 °C was found to have the best combination of ductility and strength.

Asymmetrical hot rolling (ASHR) was proposed to acquire productive grain refinement for Fe-20Mn-4Al-0.3C and Fe-18Cr-18Mn-0.5N non-magnetic austenitic steels. The intensive additional shear deformation caused by ASHR promotes the nucleation of recrystallization and grain refining of steel plates. With the speed ratio of 1.2, the austenitic grains were refined to ∼5 μm on the surface, the recrystallization fraction was enhanced to ∼34.7%, and the thickness of fine-grained surface layer increases to ∼450 μm for Fe-20Mn-4Al-0.3C steel. The Fe-18Cr-18Mn-0.5N steel also exhibited an effective surface grain refinement with an average size of ∼3 μm, and the recrystallization fraction reached ∼76.9% at the speed ratio of 1.15.

Saline water irrigation can change soil environment, which thereby influence soil microbial process. Based on a field experiment, the shifts in soil microbial metabolic activities and community structures under five irrigation salinities were studied using Biolog and metagenomic methods in this study. The results demonstrated that microbial metabolic activities were greatly restrained in saline water irrigated soils, as average well color development (AWCD) reduced under all saline water irrigation treatments. Although no significant difference in carbon substrate utilization of all six categories was observed among Mild, Medium, High and Severe treatments, the consumption of sole carbon source was significantly varied. Especially, asparagine, galacturonic, putrescine and 4-benzoic acid played a decisive role in dominating the differences. Soil bacterial richness and diversity increased with irrigation salinity while the number of bacterial phyla decreased. Three significantly increased (Proteobacteria, Actinobacteria and Chloroflexi), two decreased (Planctomycetes, Bacteroidetes) and two irresponsive (Gemmatimonadetes and Acidobacteria) phyla were observed as the dominant groups in saline water irrigated soils. The results presented here could improve the understanding of the soil biological process under saline circumstance.

In the present study, a duplex TRIP steel (Fe-0.232C-2.0Si-2.39Mn-2.01Al wt%) was successfully produced by a novel processing route involving twin-roll strip casting (TRSC), heat treatment, cold rolling and annealing for the first time. The evolution of microstructure during the entire processing route was extensively studied that included determination of mechanical properties and fractography of tensile specimens of annealed sheets. It was observed that the as-cast strip microstructure consisted of ferrite and martensite. The morphology at the surface and the center was dendritic and equiaxed, respectively. On using an appropriate heat treatment schedule (heat treatment at 780 °C for 10 min followed by direct quenching), a duplex structure of ferrite and retained austenite (RA) in the heat-treated strip was obtained that was suitable for cold rolling. Annealing temperature was very critical for microstructure and mechanical properties of the annealed sheets. Annealing at 780 °C for 5 min followed by direct quenching yielded a duplex structure of ferrite and RA (volume fraction of ~22%), which exhibited an excellent combination of tensile strength and total elongation of 945 MPa and 28.56%, respectively.

Small heat shock proteins (shsps) are conserved across invertebrate species. They are implicated in the modulation of various biological processes, such as immune responses, abiotic stress tolerance metamorphosis, and embryonic development. Herein, we identified a heat shock protein 20 from the red swamp crayfish, Procambarus clarkii (named as Pc-Hsp20), and performed in vivo studies to elucidate its physiological functions in the innate immunity. The open reading frame of Pc-Hsp20 was 609 base pair, encoding a protein of 202 amino acid residues with a hsp20/alpha crystallin family domain. Pc-Hsp20 was ubiquitously expressed in various tissues; however, it was highest in the hepatopancreas. The challenge with immune elicitors remarkably enhanced the transcript level of Pc-Hsp20 in the hepatopancreas when compared with the control. Administration of double-stranded RNA could significantly reduce expression of the Pc-Hsp20 mRNAs, and most of the immune-related genes expression enhanced with a variable concentration in the hepatopancreas. Altogether, these results suggest that Pc-Hsp20 may participate in innate immunity against microbial pathogens.

This paper presents a facile and effective method for preparing Ni/NbSe2 composites in order to improve the wettability of NbSe2 and copper matrix, which is helpful in enhancing the friction-reducing and anti-wear properties of copper-based composites. The powder metallurgy (P/M) technique was used to fabricate copper-based composites with different weight fractions of Ni/NbSe2, and tribological properties of composites were evaluated by using a ball-on-disk friction-and-wear tester. Results indicated that tribological properties of copper-based composites were improved by the addition of Ni/NbSe2. In particular, copper-based composites containing 15 wt.% Ni/NbSe2 showed the lowest friction coefficient (0.16) and wear rate (4.1 &times, 10&minus, 5 mm3&middot, N&minus, 1&middot, m&minus, 1) among all composites.

A 3D profiled blank (3D-PB) is a variable thickness in both the rolling direction (RD) and transversal direction (TD). A novel method of manufacturing 3D-PB is proposed in this paper. The method combines two processes: first, the workpiece of a normal blank is rolled into a tailor rolled blank (TRB) through variable gauge rolling (VGR), then the TRB is rolled into a 3D-PB through variable thickness rolling (VTR). A significant modification was made to VGR as the original VTR could not be adapted to the production of 3D-PB. The metal flow of the thick and thin areas of the 3D-PB was investigated with finite element simulation. The metal in the thin area mainly flows in the TD. The deformation of the workpiece was studied during the process. The workpiece was first bent and then thinned, resulting in a different width between the thick and thin areas. The thickness difference between the thick and thin areas of the 3D-PB was explained through simulation and controlled rolling experiments. The final 3D-PB has a variable thickness in both the RD and TD with good shape.

Shear deformation along the longitudinal cross section of the high-manganese steel strip has been analyzed in hot asymmetrical rolling process using rigid-plastic finite element model. The friction coefficient between the rolls and the strip surfaces, the diameter of the work rolls, the speed ratio for the lower/upper rolls, the reduction rate and the initial temperature of the billet were all taken into account. Influence of these process parameters on the shear stress, the shear strain and the related shear strain energy in the center layer of the hot-rolled strip was analyzed. It is indicated that increasing the speed ratio, the reduction rate and the work roll diameter is an effective way to accumulate more shear strain energy in the strip center. A mathematical model reflecting the relationship between the shear strain energy and the process parameters has been established.

Irrigation and fertilization can change soil environment, which thereby influence soil microbial metabolic activity (MMA). How to alleviate the adverse effects by taking judicious saline water irrigation and fertilization regimes is mainly concerned in this research. Here, we conducted a field orthogonal designed test under different saline water irrigation amount, water salinity, and nitrogen fertilizer application. The metabolic profiles of soil microbial communities were analyzed by using the Biolog method. The results demonstrated that irrigation amount and fertilizer application could significantly change MMA while irrigation water salinity had no significant effect on it. Medium irrigation amount (30 mm), least (50 kg ha−1) or medium (350 kg ha−1) N fertilizer application, and whatever irrigation water salinity could obtain the optimal MMA. Different utilization rates of carbohydrates, amino acids, carboxylic acids, and polymers by soil microbial communities caused the differences of the effects, and D-galactonic acid γ-lactone, L-arginine, L-asparagine, D-glucosaminic acid, Tween 80, L-threonine, and D-galacturonic acid were the indicator for distinguishing the effects. The results presented here demonstrated that by regulating irrigation water amount and fertilizer application, the effects of irrigation salinity on MMA could be alleviated, which offered an efficient approach for guiding saline water irrigation.

Magnetic properties of conventional grain-oriented electrical steel sheets are different in various directions. In the present paper, Epstein standard samples were cut with different angles to rolling direction, and the corresponding magnetic properties of samples were tested. Results show that the hard magnetization direction to the rolling direction is around 60°. Conventional elliptical models are not accurate to simulate permeability at all magnetic intensities, and parabolic and hybrid models with high accuracy are proposed to simulate relations between permeability and magnetization direction. When magnetic intensity is no less than 10 000 A/m, hybrid model can be used, and when magnetic intensity is less than 10 000 A/m, parabolic model should be applied. Two-stage relation model of permeability and magnetization angles is of significance in improving the accuracy of electromagnetic engineering calculations of electrical steel and can be applied in industrial applications.

Microstructural evolution and mechanical properties of cryogenic rolled Fe-36Ni steel were investigated. The annealed Fe-36Ni steel was rolled at cryogenic temperature (123–173 K) with 20%–90% rolling reduction in thickness. The deformation process was accompanied by twinning at cryogenic temperature, and the mean thickness of deformation twins was about 200 nm with 20% rolling reduction. When the rolling reduction was above 40%, twinning was suppressed due to the stress concentration in the tested steel. Deformation microstructure of Fe-36Ni steel consisted of both twin boundaries and dislocations by cryogenic rolling (CR), while it only contained dislocations after rolling at room temperature (RT). The tensile strength of Fe-36Ni steel was improved to 930 MPa after 90% reduction at cryogenic temperature, while the tensile strength after 90% reduction at RT was only 760 MPa. More dislocations could be produced as the nucleation sites of recrystallization during CR process.

Setup calculation function of the process control system for tandem cold rolling mills not only determinates the dimension accuracy of finished strip materials directly, but also affects the control of surface quality of strip materials. In the present work, an attempt was made to develop a new setup calculation method for tandem cold rolling mills to maximize the throughput and improve the surface quality of strips. Based on the application platform for level-2 process control system, the modular design method was adopted, and then the setup calculation function was developed. And four functional modules consisting of preset preparation module (PPM), basic setup calculation module (BSCM), dynamic setup calculation module (DSCM), and adaptive calculation module (ACM) were developed. The preset data from PPM were used in equipment of level-1 process control system, and the purposes of BSCM was to achieve high quality of products, reduce off thickness deviation and achieve stable rolling at maximum possible rolling speed for raising productivity. In order to minimize off error of preset and actual data, DSCM was provided. Thanks to the design of ACM, accuracy of mathematical model can be effectively improved on line. Ultimately, the precise model on setup calculation method for cold tandem rolling of strip steels was established, and then it was put into practical production. Statistics analysis showed that the measured data was in excellent agreement with the model, and exactly, the relative deviations on rolling force and delivery thickness of strips were less than 3.67% and 0.42%, respectively. The new setup calculation method has high precision and good generalization capability.

The fabric of gravels can significantly affect the characteristics of deformation, stress field and failure of soil–rock mixture. The computed tomography (CT) was used to obtain the shape and location of gravels in triaxial soil–rock mixture samples. Based on the CT images, the typical longitudinal profiles of triaxial sample were reconstructed and the wire-frame models indicating the interfaces between the soil matrix and gravels were built through digital image processing (DIP), including image binarization, noise removal and interface detection. A mesh generator, DISTMESH was utilized to improve meshing quality, especially near the interfaces. The mesh was exported to FLAC3D using an interface program and 2D plane strain models with different gravel content were simulated for verification. It was found that cracks usually first appear on certain parts of the soil/gravel interfaces where the shear stress is prone to accumulate. The location of cracks have a good consistency with the results obtained by CT images. It can be concluded that the method proposed is efficient and accurate for the behavior analysis of soil–rock mixture by using numerical simulation and triaxial test with CT scan.

Spatial variations of soil microbial activities and its relationship with environmental factors are very important for estimating regional soil ecosystem function. Based on field samplings in a typical saline groundwater-irrigated region, spatial variations of soil microbial metabolic activities were investigated. Combined with groundwater quality analysis, the relationship between microbial activities and water salinity was also studied. The results demonstrated that moderate spatial heterogeneity of soil microbial activities presented under the total dissolved solids (TDS) of groundwater ranging from 0.23 to 12.24 g L(-1). Groundwater salinity and microbial activities had almost opposite distribution characteristics: slight saline water was mainly distributed in west Baqu and south Quanshan, while severe saline and briny water were dominant in east Baqu and west Huqu; however, total AWCD was higher in the east-center and southwest of Baqu and east Huqu, while it was lower in east Baqu and northwest Huqu. The results of correlation analyses demonstrated that high-salinity groundwater irrigation had significantly adverse effects on soil microbial activities. Major ions Ca(2+), Mg(2+), Cl(-), and SO4(2-) in groundwater decisively influenced the results. Three carbon sources, carbohydrates, amines, and phenols, which had minor utilization rates in all irrigation districts, were extremely significantly affected by high-salinity groundwater irrigation. The results presented here offer an approach for diagnosing regional soil ecosystem function changes under saline water irrigation.