To explore the factors affecting the successful rate of nano-carbon in sentinel lymph node biopsy.
A total of 270 patients with breast cancer, who were treated in First Affilitated Hospital of Henan ...University of Science and Technology from January 2013 to March 2015, were chosen and given sentinel lymph node biopsy (SLN) with nano-carbon, and the influencial factors were examined by logistic analysis.
Successful rate of biopsy, accuracy, sensitivity and false negative rate was 92.2%, 97.6%, 93.1% and 6.8%, respectively. Age, primary tumor lesions, body mass index, axillary lymph node status, number of SLN and pathological grade were the factors affetcing successful biopsy (all P<0.05), and body mass index, age, and number of SLN were three independent factors affecting the successful rate of biopsy (all P<0.05). The history of biopsy, tumor location, affected sides, injection sites and chemotherapy showed little effect on the successful rate of biopsy (all P> 0.05).
Nano-carbon tracer method is a reliable
•Influence of oxygen pressure and temperature on AlF3 films was characterized.•Alumina was detected and the formation mechanism was analyzed.•Samples prepared with oxygen contain more alumina, and ...the mechanical stress was reduced.•By introducing oxygen, extinctive coefficient was reduced and the refractive index was increased.•Samples prepared with certain oxygen pressure tend to be more laser resistant.
Single layers of AlF3 were deposited at different substrate temperature by resistant heating technique in vacuum and in certain oxygen pressure. The chemical composition, total stress, optical constants and laser damage resistance were characterized. Comparative study indicates that AlF3 films deposited under certain oxygen pressure and lower temperature tend to absorb more water when exposed to air and as a result, their total stress and optical absorption are reduced. These differences and the increased laser-induced damage threshold (LIDT) at 355nm demonstrate that reasonable oxygen pressure and substrate temperature may improve AlF3 films’ UV performance.
•The relationship between flowing properties and sulfur content of cemented sulfur tailings backfill (CSTB) is revealed.•Based on SEM and XRD techniques, the effect of sulfur content variation on ...mechanical properties of cemented sulfur tailings backfill is investigated.•By adding polypropylene fibers to the CSTB, the prediction models for compressive and tensile strength are proposed considering fiber modification coefficient.•Based on SEM and XRD techniques, the effect of polypropylene fibers on mechanical properties of cemented sulfur tailings backfill is investigated.
In this paper, the mechanics, flowing and microstructural properties of the cemented sulfur tailings backfill (CSTB) have been studied by means of flow performance test, uniaxial compression test, scanning electron microscope test and X-ray energy spectrum test. On the basis of previous results, a new way was proposed to improve the mechanical performance of CSTB. The research results show that the fluidity of sulfur tailings slurry increases exponentially with the increase of sulfur content, because the density of sulfide concentrate is greater than that of tailings. The adding of polypropylene fiber will reduce the fluidity of sulfur tailings slurry and the fluidity of the slurry decreases exponentially with the increase of fiber content. The compressive strength and 28d splitting tensile strength of the CSTB both increased first and then decreased with the increase of the sulfur content, and reached the maximum when the sulfur content was 12%. However, the CSTB exhibits obvious strength deterioration characteristics when the curing age exceeds 28 days. The compressive strength and 28d tensile strength of the CSTB both increased first and then decreased with the increase of fiber content, and then, reached the maximum when the fiber content is 0.6%. In addition, the effect of adding polypropylene fiber on improving the tensile strength is better than that of compressive strength. SEM and X-ray energy spectrum analysis results show that a certain amount of secondary gypsum and ettringite crystals can effectively fill the pores in the CSTB, which contributes to the development of strength. However, when the sulfur content exceeds the critical content, there are obvious pore structures and a large number of expansive minerals such as gypsum and ettringite in the CSTB, which leads to the strength deterioration of the CSTB. The special spatial skeleton structure formed by polypropylene fibers in the CSTB matrix can play a significant physical reinforcement effect and the reinforcement effect is mainly controlled by the bonding effect between the fiber and the CSTB matrix interface. In addition, the compressive strength, tensile strength and fluidity prediction models of the fiber reinforced CTSB constructed based on the fiber modification coefficient can accurately predict the compressive strength, tensile strength and fluidity parameters, which can provide certain guidance for engineering applications.
•The energy parameters at characteristic stress point for diffetent curing ages was studied.•The energy damage evolution mechanism of the CTB was revealed.•An energy criterion for strength failure of ...the CTB was established.
This study attempted to explore, at curing age, the characteristics stress and energy evolution of the cemented tailings backfill (CTB) under uniaxial compression. Based on the energy consumption theory, the energy parameters at the characteristic stress varing with the curing age was analyzed. Furthermore, the evolution law of energy distribution and the energy damage mechanism of the CTB were revealed, and the failure criterion of the CTB was established based on the elastic energy consumption ratio. The results showed that the characteristic stress of the CTB follow an exponential function increasing law with the increase of curing age and the characteristic stress of the CTB with larger cement-to-tailings (c/t) ratio increases more rapidly when the curing age is 3d ~ 14d. The total energy, elastic strain energy and consumption energy at the peak stress point of the CTB all follow the exponential function increasing law with the increase of curing age, and the increase of cement-to-tailings (c/t) ratio and curing age can significantly improve the energy storage limit of the CTB. The deformation and failure of the CTB mainly go through five stages: initial crack compaction stage, linear elastic deformation stage, steady development stage of microcrack, accelerated crack expansion stage and post-peak failure stage. According to the damage value D of the CTB and the growth law of dissipated energy, elastic strain energy and axial strain, the loading damage of cemented CTB can be divided as follow: initial damage stage, damage stationary stage, damage stable stage, damage rapid stage and damage failure stage. The slow growth and abrupt change of the elastic energy consumption ratio K in the post-peak stage can be used as the criterion for strength instability of the CTB.
By preparing fine tailings slurry with different mass concentration and fiber content, the rheological parameters of slurry with different fiber content and curing time were tested. In addition, the ...influence law of fiber content and curing time on compressive strength was analyzed through the prepared fine tailings backfill samples, and the microstructure characteristics of fine tailings backfill were further studied. The results show that when the fiber content is 0.2 ~ 1.2%, the yield stress and plastic viscosity of the slurry increase with the increase of fiber content, and the thixotropy of the slurry also shows the same change characteristics. The bridge effect of fiber makes it easier for forming network structure, which increase the slurry rheology. When the curing time ranges from 0 h to 2.5 h, the increasing of curing time leads to the increasing trend of rheological parameters, and also increases the thixotropy of slurry. However, the increase of rheological parameters will continuously decrease when the curing time exceeds 1 h, indicating that the influence of curing time on yield stress and thixotropy will gradually weaken with the continuous extension of curing time. When the curing age increases from 3 to 56 days, the compressive strength of the fine tailings backfill increases with the curing age, but the increasing range of compressive strength decreases gradually. When the fiber content ranges from 0.2 to 1.2%, the compressive strength of backfill increases first and then decreases with the increase of fiber content, and reaches the maximum value when the fiber content is 0.6%. The extension of curing time reduces the generation of large-scale pore structure, which promotes the formation of more compact microstructure of backfill.
•The effects of sulfur content and polypropylene fiber on the mechanical properties, failure pattern and damage evolution of the CSTB were systematically studied.•The fiber factor γ is introduced to ...measure the impact of polypropylene fiber on mechanical behavior of CSTB.•The piecewise damage constitutive model taking fiber factor γ into consideration was established.
In order to explore the mechanical properties of cemented sulfur tailings backfill (CSTB), uniaxial compression tests of cemented sulfur tailings backfill (CSTB) were carried out in the laboratory, and the effects of sulfur content and polypropylene fiber on the mechanical properties, failure pattern and damage evolution of the CSTB were systematically studied. Moreover, fiber factor γ is introduced to measure the impact of polypropylene fiber on mechanical behavior of CSTB. The peak stress, residual stress and elastic modulus of the CSTB all increase initially and decrease afterwards with the fiber factor γ increasing. When the fiber content is 0%∼0.6%, the three factors show exponential and quadratic function with the fiber factor γ increasing. The total strain energy, elastic strain energy and dissipative strain energy of CSTB at the peak stress point all increase first and then decrease with the fiber factor γ increasing, and all reach the maximum value when the fiber content is 0.6%. Under uniaxial loading, the elastic strain energy of CSTB presents a change characteristic of “gentle - rapid increase - slow increase - rapid decline” with the increasing axial strain, while the dissipative strain energy presents a change characteristic of “gentle - steady increase - rapid increase”. In addition, each strain energy (dissipative strain energy, total strain energy and total strain energy) of CSTB at the peak stress point all increase initially and decrease afterwards with the fiber factor γ increasing. Then, the piecewise damage constitutive model taking fiber factor γ into consideration was established. Under uniaxial loading, the damage evolution of backfill can be divided into four stages: no damage stage, slow growth stage, acceleration stage and damage failure stage. It shows that polypropylene fiber can effectively inhibit the damage and failure of CSTB, thus improving the bearing capacity and anti-deformation and failure ability of CSTB. The CSTB without fiber shows obvious shear failure characteristics, and there are obvious large-scale “Y-shaped” and “linear” failure cracks on the sample surface. There is not only one or two major large-scale cracks in the failure of CSTB containing fiber, but also the range of fracture surface is very limited, indicating that adding fiber can effectively inhibit the crack propagation of CSTB during failure and improve the overall anti-crack ability of CSTB.
Abstract To systematically examine the mechanical properties and microstructure of fly ash-doped wet shotcrete under low-temperature curing conditions, experimental studies were conducted on the ...compressive strength. The investigations encompassed varying activator dosage, fly ash dosage, and curing temperature for a thorough examination of the material’s performance. The results show that the addition of activator can significantly improve the compressive strength of fly ash wet shotcrete under low temperature curing, but the optimal dosage of different activator types is not consistent. The selection of NaAlO 2 as the activator has the most significant effect on the compressive strength of the samples. Under low temperature curing environment, the increase of curing age can also significantly improve the compressive strength of the sample, especially the early strength. The order of influence degree of three factors on compressive strength is that alkaline activator has the highest influence degree, curing temperature has the second, fly ash content has the least influence degree, and activator content is the significant influence factor of early compressive strength. A prediction model for the compressive strength of wet shotcrete doped with fly ash was established in the low temperature curing environment, and the effect of increasing the dosage of activator on the compressive strength of the sample increased with the decrease of curing temperature. With the increase of the content of activator and curing temperature, the size of the void structure in the sample is gradually reduced, which makes the density of the microstructure gradually increase, and thus improves the macroscopic compressive strength of the sample.
The perforating bullet detection experimental device is used to simulate the downhole high-temperature and high-pressure environment in which the perforating bullet performance is test. The ...perforating test tool is inside liquid-filled cylindrical wellbore cavity that is heated by heating wellbore wall with natural convection heat transfer. A mathematical model for unsteady heat-fluid-solid coupling heat transfer between the liquid in the wellbore cavity and the perforating test tool was established. The projection method is used to numerically solve the mathematical model, and the results of the dynamic heating evolution process of the perforation experimental device are calculated. The internal flow field and temperature field of the perforation experimental device with and without the perforating test tool in the wellbore are analyzed. Through the calculation and analysis results, it is found that the perforating test tool inside the simulated wellbore cavity has a greater influence on the flow field and temperature field.
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