Abstract The construction of the cross passage changes the main tunnels segment from a complete cylindrical structure to a notched unstable stressed structure. Thus, the overall force (bending and shearing) performance of the main tunnels is considerably decreased. The excavation of the cross passage also destroys the stability of the original soil layer and main tunnels and causes difficulty in avoiding the settlement of the surface and main tunnels. Numerical simulation analysis of the mechanical characteristics and influencing factors analysis were carried out using FLAC3D. Results show that (1) the construction of the cross passage largely disturbs the main tunnels. The settlement of the intersection part of the main tunnels and cross passage is mainly concentrated from −7 m to 7 m. (2) During the construction of the cross passage, the original main tunnels are subjected to stress redistribution, which causes stress concentration in the intersecting segments, especially in the opening side segment has an unfavorable force form in which the upper and lower sections are integrally pulled. (3) The construction of the cross passage causes a large tensile stress area in the structure as well. As a result, the overall tension of the upper and lower sections of the structure and the compression of the hance are unfavorable. (4) The influence of the excavation of the cross passage on the surface and main tunnels is related to the buried depth, intersection angle, excavation method, and grouting range. Therefore, the influence of different parameters can be analyzed by changing the model parameters.

Abstract The dechlorination efficiency of zinc oxide dust using microwave roasting was investigated capitalizing on the different microwave absorbing capacities of the compounds such as chlorine, lead, and zinc oxide. The associated dechlorination reactions were discussed in detail and the effect of all the influencing parameters such as the air flow rate, steam flow rate, the roasting temperature, roasting duration, and the mixing rate were assessed to identify the optimal conditions. The results indicated that a near 93% dechlorination of zinc oxide dust could be achieved, which would satisfy the requirements of the wet smelting electrolysis process. The optimal process parameters were identified to be an air flow of 300 L/h, a steam flow of 8 mL/min, a stirring speed of 60 rpm, a roasting temperature of 650 ºC, and a roasting duration of 60 min. Water vapor has an enhanced effect on dechlorination by microwave roasting.

Abstract In this research, the effect of different citric acid concentrations, ammonia concentration, temperature, leaching time, stirring speed and liquid-to-solid ratio on the zinc leaching from low-grade zinc oxide ore in a NH3-H3C6H5O7-H2O system were studied. The results showed that the zinc leaching rate is only 4.7% when the citric acid concentration is 0 M, and the leaching efficiency of Zn increased with increasing citric acid concentration. Under the conditions: citric acid concentration of 1.0 M, ammonia concentration of 6 M, temperature of 25 °C, leaching time of 60 min, stirring speed of 300 rpm and the starting solid-to-liquid ratio of 1:5, 81.2% of Zn is leached. The mineralogical changes of the low-grade zinc oxide ores during the processes were characterized by X-ray fluorescence (XRF), X-ray powder diffraction (XRD), Scanning Electron Microscopy associated with Energy Dispersive Spectroscopy (SEM-EDS) and Fourier transform infrared spectroscopy (FT-IR). From the evidence we deduced that citric ions complexed with zinc ions, forming a Zn-citrate complex. As a result, the zinc leaching rate was improved without the risk of pollution or pretreatment. This makes it as a good choice for a more ecological treatment of hemimorphite.

Protein degradation in bovine milk affects the quality of dairy products. Alpha 1-antitrypsin (AAT) can protect vulnerable elastic tissues from degradation by neutrophil elastase. The aim of this study was to assess the association of polymorphisms in bovine AAT gene with milk yield and milk composition in Chinese Holstein. Traits analyzed were fat percentage, protein percentage, 305-day milk yield and somatic cell score (SCS). Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP), created restriction site-polymerase chain reaction (CRS-PCR) and allele specific-polymerase chain reaction (AS-PCR) methods were used to genotype five loci in coding regions of the sequence, including position 5504, 5609, 5624, 5747 and 8178 in Chinese Holstein. The five mutations were all silent mutation that caused no alteration in the amino acid sequence. In order to determine the relationship between the polymorphisms of the AAT gene and milk production traits and SCS, the General Linear Model (GLM) procedure from the Statistical Analysis Software was used. SNP5504 affected milk fat percentage, SNP8178 affected milk protein percentage and SNP5609 and SNP5624 affected 305-day milk yield. These results suggest that AAT is a candidate gene that influences milk production traits and it could be implemented in breeding programmes to improve the production performance of Chinese Holstein cattle.

We investigated the association between myeloperoxidase gene -463G > A polymorphism and premature coronary artery disease (CAD) in two Chinese population samples: 229 patients and 230 controls. Genotypes were determined by ligase detection reaction-polymerase chain reaction sequencing and the grouping technique. We found lower frequencies of both the A/A genotype and the A allele in patients (p < 0.05). Multivariate logistic regression showed that the risk of premature CAD in subjects carrying the AA genotype was reduced by 83% in relation to individuals carrying the G/G genotype (OR = 0.172, 95% CI: 0.057-0.526, p = 0.002). Our results indicate that -463G > A polymorphism of the myeloperoxidase gene is associated with premature CAD in Chinese individuals, suggesting that the AA genotype is a protective factor against premature CAD.