Carbonate-activated binder modified by supplementary materials for mine backfill and the associated heavy metal immobilization effects

Cemented paste backfill(CPB)is one of the effective methods for resource utilization of tailings,but the high cost of ordinary Portland cement(OPC)limits its utilization.Considering the poor performance of Na_(2)CO_(3)-activated binders,in this work,supplementary materials,including CaO,MgO,and calcined layered double hydroxide(CLDH),were used to modify their properties with the aim of finding an alternative binder to OPC.Isothermal calorimetry,X-ray diffraction,and thermogravimetric analyses were conducted to explore the reaction kinetics and phase assembles of the binder.The properties of the CPB samples,such as flowability,strength development,and heavy metal immobilization effects,were then investigated.The results show that the coupling utilization of MgO and CLDH showed good performance.The strength of the Mg_(2)-CLDH_(3) sample was approximately 2.94 MPa after curing for 56 d,which was higher than that of the OPC-based sample.Moreover the cost of the modified Na_(2)CO_(3)-activated binder was lower than that of the OPC-based binder.Modified sample showed satisfactory heavy metal immobilization effects.These findings demonstrate that carbonate-activated binder modified by supplementary materials can be suitable in CPB.

Identification of proteins of human colorectal carcinoma cell line SW480 by two-dimensional electrophoresis and MALDI-TOF mass spectrometry

AIM: To conduct the proteomic analysis of human colorectal carcinoma cell line, SW480 by using two-dimensional electrophoresis (2-DE) and matrix-assisted laser desorption /ionization-time of flight mass spectrometry (MALDITOFMS).METHODS: The total proteins of human colorectal carcinoma cell line, SW480 were separated with 2-DE by using immobilized pH gradient strips and visualized by staining with silver nitrate. The gel images were acquired by scanner and 2-DE analysis software, Image Master 2D Elite. Nineteen distinct protein spots were excised from gel randomly and digested in gel by TPCK-trypsin. Mass analysis ofthe tryptic digest peptides mixture was performed by using MALDI-TOF MS. Peptide mass fingerprints (PMFs) obtained by the MALDI-TOF analysis were used to search NCBI,SWISS-PROT and MSDB databases by using Mascot software.RESULTS: PMF maps of all spots were obtained by MALDI-TOF MS and thirteen proteins were preliminarily identified.CONCLUSION: The methods of analysis and identification of protein spots of tumor cells in 2-DE gel with silver staining by MALDI-TOF MS derived PMF have been established.Protein expression profile of SW480 has been obtained.It is demonstrated that a combination of proteomics and cell culture is a useful approach to comprehend the process of colon carcinogenesis.

Onion-structured transition metal dichalcogenide nanoparticles by laser fabrication in liquids and atmospheres

Since the discovery of transition metal dichalcogenide(TMDC)nanoparticles(NPs)with the onion-like structure,many efforts have been made to develop their fabrication methods.Laser fabrication(LF)is one of the most promising methods to prepare onion-structured TMDC(or OS-TMDC)NPs due to its green,flexible,and scalable syntheses.In this mini-review article,we systematically introduce various laser-induced OS-TMDC(especially the OS-MoS_(2))NPs,their formation mechanism,properties,and applications.The preparation routes mainly include laser ablation in liquids and atmospheres,and laser irradiation in liquids.The various formation mechanisms are then introduced based on the different preparation routes,to describe the formations of the corresponding OS-NPs.Finally,some interesting properties and novel applications of these NPs are briefly demonstrated,and a short outlook is also given.This review could help to understand the progress of the laser-induced OS-TMDC NPs and their applications.

Effect of addition of minor amounts of Sb and Gd on hot tearing susceptibility of Mg-5Al-3Ca alloy

The effects of addition of minor amount of(0.5 wt.%) antimony(Sb) or gadolinium(Gd) and combined addition of Sb and Gd(0.5 wt.%,respectively) on the hot tearing susceptibility(HTS) of Mg-5Al-3Ca alloy were investigated experimentally using a “T-shaped” hot tearing measuring system. Various solidification parameters of the alloys were measured and calculated through thermal analysis experiments. The microstructure, grain size, and morphology of the crack zone were characterized by scanning electron microscopy and electron backscatter diffraction, and the crystal phases of the alloys were analyzed by X-ray diffraction and energy-dispersive X-ray spectroscopy. The results showed that the addition of 0.5 wt.% Gd resulted in the increase in the vulnerable temperature range(Tv) and reduced the eutectic structure content that could participate in feeding, thereby improving the HTS of the alloy. However, addition of 0.5 wt.% Sb or combined addition of Gd and Sb(0.5 wt.%, respectively) to the Mg-5Al-3Ca alloy shortened the Tvand improved the skeleton strength of the alloy, thereby reducing HTS. Moreover, significantly refined structure of Mg-5Al-3Ca-0.5Gd-0.5Sb alloy improved the feeding ability of the eutectic structure, thus the alloy exhibited the lowest HTS.

岩石蠕变模型及蠕变参数识别研究综述

蠕变特性是岩石重要的力学特性之一。根据各种岩石蠕变模型的特点,总结了国内外学者对于岩石蠕变模型的研究进展,介绍了现有主要三种类型的蠕变模型和其适用性,即经验模型、元件组合模型和断裂损伤模型。对蠕变参数识别方法进行了介绍和总结。提出了建立蠕变模型和参数识别需要考虑的问题。

2000—2015年夏秋季孟加拉湾湾口区涡流相互作用能量学特征

文章主要使用全球简单海洋资料同化分析系统(Simple Ocean Data Assimilation,SODA)产出的海洋再分析数据产品和美国国家环境预报中心(National Centers for Environmental Prediction,NCEP)发布的风场资料,通过能量学方法分析了2000—2015年夏季至秋季(6—11月)孟加拉湾涡-流相互作用特征在不同印度洋偶极子(Indian Ocean Dipole,IOD)事件发生年的表现。结果表明,在IOD负位相年更强的西南季风背景下,涡动能和涡势能的量值均较大,海洋不稳定过程更多地将平均流场的能量输向涡旋场,IOD正位相年反之。另外,研究发现孟加拉湾湾口区的涡动能在个别年份会发展出一种与气候态存在显著异常的空间分布,即在个别年份湾口中央海域异常出现涡动能极大值。通过对出现该异常现象最显著的2010年进行个例分析,发现当年的孟加拉湾海表风场发展出一个气旋式环流异常,显著地改变了海洋上层环流形态,极大地影响了平均流场与涡旋场之间的相互作用。进一步对维持涡动能平衡的各做功项进行诊断后发现,湾口异常海域涡动能年际变化的主要影响因素为海洋内部的压强做功,其次是正压不稳定过程和平流的做功,海表风应力做功项贡献较小。

Kernel Generalization of Multi-Rate Probabilistic Principal Component Analysis for Fault Detection in Nonlinear Process

In practical process industries,a variety of online and offline sensors and measuring instruments have been used for process control and monitoring purposes,which indicates that the measurements coming from different sources are collected at different sampling rates.To build a complete process monitoring strategy,all these multi-rate measurements should be considered for data-based modeling and monitoring.In this paper,a novel kernel multi-rate probabilistic principal component analysis(K-MPPCA)model is proposed to extract the nonlinear correlations among different sampling rates.In the proposed model,the model parameters are calibrated using the kernel trick and the expectation-maximum(EM)algorithm.Also,the corresponding fault detection methods based on the nonlinear features are developed.Finally,a simulated nonlinear case and an actual pre-decarburization unit in the ammonia synthesis process are tested to demonstrate the efficiency of the proposed method.

Deformation mechanism of fine grained Mg-7Gd-5Y-l.2Nd-0.5Zr alloy under high temperature and high strain rates

Fine grained Mg-7Gd-5Y-1.2Nd-0.5Zr alloy was investigated by dynamic compression tests using a Split Hopkinson Pressure Bar under the strain rates in the range 1000-2000 s^(-1) and the temperature range 293-573 K along the normal direction.The microstructure was measured by optical microscopy,electron back-scattering diffraction,transmission electron microscopy and X-ray diffractometry.The results showed that Mg-7Gd-5Y-1.2Nd-0.5Zr alloy had the positive strain rate strengthening effect and thermal softening effect at high temperature.The solid solution of Gd and Y atoms in Mg-7Gd-5Y-1.2Nd-0.5Zr alloy reduced the asymmetry of α-Mg crystals and changed the critical shear stress of various deformation mechanisms.The main deformation mechanisms were prismatic slip and pyramidal(a)slip,{102}tension twinning,and dynamic recrystallization caused by local deformation such as particle-stimulated nucleation.c 2020 Published by Elsevier B.V.on behalf of Chongqing University.

Comparison of the Effects of Minimally Invasive Percutaneous Nephrolithotomy and Open Surgery on Kidney Stones

Objective:To compare the treatment effects of minimally invasive percutaneous nephrolithotomy and open surgery on kidney stones.Methods:From November 2018 to November 2019,80 patients with kidney stones who were treated in our hospital were selected and divided into two groups according to the random number table method.Each group contained 40 patients.The patients in control group were treated with open surgery while the patients in observation group were treated with minimally invasive percutaneous nephrolithotomy.The surgical indicators,rate of stone removal,and adverse events were compared between the two groups.Results:There was no statistically significant difference in surgical time between the two groups(P>0.05).Compared with the control group,the observation group had less intraoperative blood loss and shorter hospital stay,and the differences were statistically significant(P<0.05).The stone clearance rate(95.00%)in the observation group was higher than that in the control group(77.50%),and the difference was statistically significant(P<0.05).Compared with the control group,the incidence of postoperative adverse effects was lower in the observation group,and the difference was statistically significant(P<0.05).Conclusion:Minimally invasive percutaneous nephrolithotomy for kidney stones is effective in reducing the intraoperative blood loss,shortening the length of hospital stay,improving the rate of stone clearance and reducing the occurrence of adverse effects.Therefore,this treatment method should be promoted for clinical use.

Effect of long-period stacking ordered phase on hot tearing susceptibility of Mg-lZn-xY alloys

The effect of long-period stacking ordered(LPSO)phase on hot tearing susceptibility of Mg-1 Zn-xY serial alloys were investigated experimentally using a home-made T-type hot tearing mold.The characteristic parameters related to HTS during the solidification process were calculated by thermal analysis.The microstructure and morphology of the crack zone were characterized by optical microscope(OM),scanning electron microscopy(SEM)and electron dispersive spectrometer(EDS),and the phases of the alloys were analyzed by X-ray diffraction(XRD).The result showed that the long-period stacking ordered(LPSO)phase formed when m(Zn)/m(Y)<1,and the LPSO content increased with increasing of Y.The presence of the LPSO phase in Mg-lZn-xY alloys could benefit the hot tearing refilling and decrease the HTS of the alloys.With in creasing the content of LPSO phase,the HTS of the alloys decreased.LPSO phase increased the skeleton strength,and reduced the HTS of Mg-lZn-xY alloys.

Research Progress of Transurethral Prostatectomy for Benign Prostatic Hyperplasia with Bladder Stones

Benign prostatic hyperplasia,which can be abbreviated as prostatic hyperplasia,is a urinary system disease that has a high incidence in middle-aged and elderly male populations in China.The incidence of benign prostatic hyperplasia is increasing year by year.Patients with benign prostatic hyperplasia are prone to have bladder outlet obstruction,which in turn leads to an increase in residual urine volume in the bladder and impurities in the urine,such as upper urinary calculi that enter the bladder,urine crystals,various exfoliated cells,etc.If these substances stay in the bladder for a long time,stones in the bladder will be generated.Benign prostatic hyperplasia with bladder stones can severely obstruct the urinary tract,causing clinical symptoms such as urinary tract infections,urinary urgency,frequent urination,and dysuria.These symptoms seriously affects the physical and mental health of patients,leading to low levels of normal work and quality of life.With the development of medical technology,surgical treatment is commonly used in clinical practice.Among them,transurethral prostatectomy is widely used in clinical treatment,and has achieved good results.

Overview of chemical constituents and pharmacological activities of Piper longum Linn.

Piper longum Linn. is a native of the Indo-Malaya region, belongs to the family Piperaceae. It is a slender aromatic climber widely distributed in the tropical and subtropical regions. As a traditional ethnic drug, P. longum contains various chemical constituents such as alkaloids, volatile oil and lignans. The extract of P. longum has been reported to show various activities like antitumor, antioxidant and hepatoprotective activity. Hence, this paper is presented as a review centered on the main chemical constituents and pharmacological effects of P. longum, aiming at its further development and potential value.

An alfalfa MYB-like transcriptional factor MsMYBH positively regulates alfalfa seedling drought resistance and undergoes MsWAV3-mediated degradation

Drought is a major threat to alfalfa(Medicago sativa L.)production.The discovery of important alfalfa genes regulating drought response will facilitate breeding for drought-resistant alfalfa cultivars.Here,we report a genome-wide association study of drought resistance in alfalfa.We identified and functionally characterized an MYB-like transcription factor gene(MsMYBH),which increases the drought resistance in alfalfa.Compared with the wild-types,the biomass and forage quality were enhanced in MsMYBH overexpressed plants.Combined RNA-seq,proteomics and chromatin immunoprecipitation analysis showed that MsMYBH can directly bind to the promoters of MsMCP1,MsMCP2,MsPRX1A and MsCARCAB to improve their expression.The outcomes of such interactions include better water balance,high photosynthetic efficiency and scavenge excess H_(2)O_(2)in response to drought.Furthermore,an E3 ubiquitin ligase(MsWAV3)was found to induce MsMYBH degradation under long-term drought,via the 26S proteasome pathway.Furthermore,variable-number tandem repeats in MsMYBH promoter were characterized among a collection of germplasms,and the variation is associated with promoter activity.Collectively,our findings shed light on the functions of MsMYBH and provide a pivotal gene that could be leveraged for breeding drought-resistant alfalfa.This discovery also offers new insights into the mechanisms of drought resistance in alfalfa.

离子液体/羊毛纤维/凝固剂三元相图的构建

三元相图是研究羊毛角蛋白再生过程热力学行为的有效工具。通过浊度测试和Boom经验方程构建离子液体(IL)/羊毛纤维/凝固剂浊点线性关系(LCP)曲线和三元相图,进一步系统地研究了凝固剂种类、再生温度和离子液体结构对羊毛角蛋白再生性能的影响规律。结果表明,羊毛角蛋白最优再生体系是1-乙基-3-甲基咪唑磷酸二乙酯([Emim]Dep)/羊毛纤维/水(25℃)。对羊毛纤维原料和不同再生条件获得的再生羊毛角蛋白进行FT-IR和XRD表征,结果表明再生羊毛角蛋白的结构和羊毛纤维原料基本保持一致,但相对结晶度有所下降。实验温度为25℃时,以水为凝固剂制备的再生羊毛角蛋白相对结晶度最高。

Microstructure, precipitates and mechanical properties of powder bed fused inconel 718 before and after heat treatment

IN718 alloy was fabricated by laser powder bed fusion(PBF) for examination of microstructure, precipitates and mechanical properties in the as-built state and after different heat treatments. The as-built alloy had a characteristic fine cellular-dendritic microstructure with Nb, Mo and Ti segregated along the interdendritic region and cellular boundary. The as-built alloys were then subjected to solution heat treatment(SHT) at 980°C or 1065°C for 1 h. SHT at 980°C led to the formation of δ-phase in the interdendritic region or cellular boundary. The segregation was completely removed by the SHT at 1065°C, but recrystallization was observed, and the carbides decorated along the grain boundaries. The as-built alloy and alloys with SHT at 980°C and 1065°C were two-step aged, which consisted of annealing at 720°C for8 h followed by annealing at 620°C for 8 h. Transmission electron microscopy revealed the precipitation of λ’ and λ" in all alloys after two-step aging, but the amount and uniformity of distribution varied. The Vickers hardness of the PBF IN718 alloy increased from 296 HV to 467 HV after direct aging. The hardness decreased to 267 HV and 235 HV after SHT at 980°C and 1065°C, respectively, but increased to 458 HV and 477 HV followed by aging. The evolution of Young’s modulus after heat treatment exhibited similar trend to that of hardness. The highest hardness was observed for IN718 after SHT at 1065°C and two-step aging due to precipitation with greater amount and uniform distribution.

Nonlinear fault detection based on locally linear embedding

In this paper, a new nonlinear fault detection technique based on locally linear embedding （LLE） is developed. LLE can efficiently compute the low-dimensional embedding of the data with the local neighborhood structure information preserved. In this method, a data-dependent kernel matrix which can reflect the nonlinear data structure is defined. Based on the kernel matrix, the Nystrrm formula makes the mapping extended to the testing data possible. With the kernel view of the LLE, two monitoring statistics are constructed. Together with the out of sample extensions, LLE is used for nonlinear fault detection. Simulation cases were studied to demonstrate the performance of the proposed method.

具有显著提高的铁电与压电响应、大面积原子级平整的PVDF Langmuir-Blodgett膜

在新兴的柔性和可穿戴电子设备中,有机铁电超薄膜发挥着至关重要的作用.然而,传统方法制备的铁电性聚偏氟乙烯(PVDF)超薄膜具有较大的表面粗糙度和结构不均匀性,极大地限制了其应用与相关科学研究.本文提出了一种将Langmuir-Blodgett(LB)技术和热压法结合制备PVDF薄膜的方法,该方法简便高效,制备的薄膜具有大面积的原子级光滑表面,且膜厚可精确控制至A级别.同时,由于更均匀的偶极取向和更高的晶体质量,该超薄膜表现出高度均匀的铁电翻转特性和增强的介电和压电响应.这种方法使PVDF LB膜具有前所未有的可靠性和更优异的性能,十分有望未来应用于铁电隧道结(FTJs)和纳米机电系统(NEMS).我们进一步研究了PVDF LB薄膜的表面电荷弛豫行为,揭示了表面电势分布与纳米尺度非均匀极化翻转行为之间的耦合关系.

基于离散Tchebichef变换和聚焦评价的多聚焦图像融合方法

基于变换技术的图像融合是多聚焦图像融合中常采用的方法,融合效果明显,并具有较强的抗噪能力,但时间复杂度普遍较高.本文提出了一种基于离散Tchebichef变换和聚焦评价的多聚焦图像融合方法,根据离散Tchebichef多项式变换和相关分析(correlation)之间的联系,利用少量低阶离散Tchebichef多项式变换系数得到图像块的聚焦评价,然后对输入的多聚焦图像按聚焦评价最大原则进行融合.实验结果表明,该方法在保证融合效果的同时,有效地降低了融合时间,并对噪声有较强的鲁棒性.

A new kind of resin-based wet friction material:Non-woven fabrics with isotropic fiber networks as preforms

As an alternative to short fibers,non-woven fabrics(NWFs)were made using different types of long fibers to optimize the performance of paper-based friction materials and their technology.In this investigation,the fillers and resin were impregnated into these NWFs to prepare three kinds of wet friction material.The tribological,mechanical,and thermal properties of the new wet friction material were studied.The results indicate that the dynamic friction coefficient of the new friction material is approximately 0.12 and the static friction coefficient is approximately 0.15;the better wear rate is 0.81334×10^(-14)m^(3)·(N·m)^(-1).In addition,the temperature for 10%mass loss yielded 100°C enhancement and the tensile strength was improved by 200%,compared to previously reported values.Most importantly,the advantages include a simple preparation flow,low cost,and resource conservation.This is a promising approach for the future development of paper-based friction materials.

Elimination of extraordinarily high cracking susceptibility of aluminum alloy fabricated by laser powder bed fusion

Using the calculation of phase diagrams approach and Scheil solidification modeling,the Al-2.5Mg-1.0Ni-0.4Sc-0.1Zr alloy was designed,intentionally with an extraordinarily high cracking susceptibility,making it prime for solidification cracking during laser powder bed fusion.This study demonstrates the ability to mitigate even the most extreme solidification cracking tendencies in aluminum alloys with only minor alloying additions of Sc and Zr,0.5 wt.%max.Furthermore,by employing a simple direct ageing heat treatment,good tensile mechanical properties were observed with a yield strength of 308 MPa,an ultimate tensile strength of 390 MPa,and a total elongation of 11%.