Shear behaviour of a rock bridge sandwiched between incipient joints under the influence of hydraulic pressures

The rock bridges sandwiched in incipiently jointed rock mass were considered as barriers that block the fluid seepage,and provide certain shear strength reservation.For better revealing the influence of hydraulic pressure on the failure behaviour of rock bridges,direct shear tests were carried out through a newly proposed method on rock samples that contain two parallel incipient joints.By developing the gypsum-silicone pad coupling samples,a conventional triaxial test system was qualified to implement direct shear tests with satisfied sealing capability.The results showed that the rock bridges could be failed through the tensile failure,shear failure and mixed failure mechanism.The hydraulic pressure would facilitate the tensile failure mechanism and induce rougher fracture surfaces;while the normal stress would facilitate the shear failure mechanism and induce less rough fracture.The hydraulic pressure reduced the global shear strength of the rock block through reducing the efficient normal stress applied on the rock bridge area,which was highly dependent on the joint persistence,k.Moreover,because of the iterating occurrence of the hydraulic pressure lag with the fracture propagation,the rock bridge failure stage in the shear stress-shear displacement curves displayed a fluctuation trend.

Platanus orientalis leaves based hierarchical porous carbon microspheres as high efficiency adsorbents for organic dyes removal

Water contamination caused by hazardous organic dyes has drawn considerable attention, among all of the techniques released, adsorption has been widely used, which however to a large degree is dependent on the development of high efficiency adsorbents. Waste biomass based porous carbon is becoming the new star class of adsorbents, and thus contribute more to the sustainable development of the society. In this work, for the first time to the best of our knowledge, abundant waste fallen Platanus orientalis leaves are employed as the raw material for hierarchical activated porous carbon(APC) microspheres via a mild hydrothermal carbonization(210 ℃,12.0 h) followed by one-step calcination(750 ℃, 1.0 h). The APC microspheres exhibit a specific surface area of 1355.53 m^2·g^-1 and abundant functional groups such as O—H and C=O. Furthermore, the APC microspheres are used as the adsorbents for removal of Rh B and MO, with the maximum adsorption capabilities of 557.06 mg·g^-1 and 327.49 mg·g^-1, respectively, higher than those of the most porous carbon originated from biomass. The adsorption rates rapidly approach to 98.2%(RhB) and 95.4%(MO) within 10 min. The adsorption data can be well fitted by Langmuir isotherm model and the pseudo-second-order kinetic model, meanwhile the intra-particle diffusion and Boyd models simultaneously indicate that the diffusion within the pores is the main rate-limiting step. Besides, the APC microspheres also demonstrate good recyclability, and may also be applied to other areas such as heterogeneous catalysis and energy storage.

Hierarchical porous MgBO_2(OH) microspheres: Hydrothermal synthesis,thermal decomposition, and application as adsorbents for Congo red removal

A facile eco-friendly hydrothermal route(180 °C, 12.0 h) has been developed for the first time to the uniform hierarchical porous MgBO_2(OH) microspheres without the aid of any organic additive, surfactant or template, by using the abundant MgCl_2·6 H_2 O, H_3BO_3 and NaOH as the raw materials. The as-obtained porous microspheres exhibit a specific surface area of 94.752 mg·g^(-1), pore volume of 0.814 cm3·g^(-1), and ca. 84.0% of which have a diameter of 2.25–3.40 μm. The thermal decomposition of the porous MgBO_2(OH) microspheres(650 °C,2.5 °C·min^(-1)) leads to the porous Mg_2B_2O_5 microspheres with well-retained morphology. When utilized as the adsorbents for the removal of CR from mimic waste water, the present porous MgBO_2(OH) microspheres exhibit satisfactory adsorption capacity, with the maximum adsorption capacity q^(-1) mof 309.1 mg·g, much higher than that derived from most of the referenced adsorbents. This opens a new window for the facile green hydrothermal synthesis of the hierarchical porous MgBO_2(OH) microspheres, and extends the potential application of the 3 D hierarchical porous metal borates as high-efficiency adsorbents for organic dyes removal.

Research Progress on Lonicera japonica Thunb.Affected by Environmental Stress

Lonicera japonica Thunb.is widely distributed in China.It has strong adaptability to the environment and can maintain normal growth and development under a variety of stress conditions.It is commonly used as a medicine with its dry flower buds or newly opened flowers,named honeysuckle,and with both economic value and ecological application value.The research progress of L.japonica Thunb.under stress conditions such as temperature,drought,light,salt,heavy metals and diseases,pests and endophytic bacteria was reviewed,and the current research situation of the physiological and biochemical response mechanism,changes of photosynthetic fluorescence and accumulation of secondary metabolites of honeysuckle under different stresses was discussed,so as to provide a reference for deep-level exploring the resistance mechanism of L.japonica Thunb.in the future and lay a theoretical foundation for the high-quality authentic ecological cultivation of L.japonica Thunb.

Bioactivity Determination and Control Effect Evaluation of Three Plant Secondary Metabolites against Semiaphis heraclei

[Objective] The paper was to clarify the bioactivity of trans-2-hexenal,oregano oil and thyme oil against Semiaphis heraclei and the synergistic effect of orange peel essential oil and organosilicon on the aphidicidal activity of the three agents.[Method] With S.heraclei,the dominant species of aphids in Lonicera japonica thunb.,as the test insect,the bioactivity and control effect were evaluated by the method of leaf dipping and foliar spraying.[Result] The indoor toxicity of thyme oil was the highest,with the LC_(50) of 1.793 mg/L.Adding additives significantly increased the toxicity of the agents to S.heraclei.Among them,trans-2-hexenal+OSi,oregano oil+OSi and thyme oil+OSi had obvious synergistic effects,with the toxicity coefficients of 1.80,1.48 and 1.45,respectively.Field test showed that the corrected control effect of thyme oil was the highest after con-ventional spraying,and the toxicities of the three agents were higher than that of the control group at 7 d post spraying.Under the condition of 20%reduction of three agents and adding organosilicon,the control effect was increased by about 10% at 1 d post spraying,which was higher than that of the control group at 4 d post spraying,and reached over 98% at 14 d post spraying.[Conclusion] Thyme oil has the highest toxicity and control effect on S.heraclei.Three agents combined with organosilicon have the obvious effect of reducing the quantity and increasing the efficiency,which has the potential for further development.

Using waste to treat waste:Red mud induced hierarchical porousγ-AlOOH andγ-Al_(2)O_(3) microspheres as superior Pd support for catalytic reduction of 4-nitrophenol

Toward the imperative treatment of the industrial wastewater containing 4-nitrophenol(4-NP)and industrial solid waste red mud(RM),an innovative approach of“Using waste to treat waste”is developed.Valuable element Al is leached from the RM first,the resultant NaAlO_(2) solution is hydrothermally converted toγ-AlOOH hierarchical porous microspheres(RMγ-AlOOH HPMSs,average diameter:2.0μm,SBET:77.81 m^(2) g^(-1),pore volume:0.38 cm^(3) g^(-1))in the presence of urea.The subsequent mild thermal conversion results inγ-Al_(2)O_(3) hierarchical porous microspheres(RMγ-Al_(2)O_(3) HPMSs).Both of the RMγ-AlOOH and RMγ-Al_(2)O_(3) HPMSs are employed as the Pd catalyst support for the catalytic reduction of 4-NP.Particularly,the as-obtained composite Pd/RMγ-AlOOH and Pd/RMγ-Al_(2)O_(3) exhibit excellent catalytic activities with superior knor as 8204.5 and 4831.4 s^(-1) g^(-1),respectively,significantly higher than that of most Pd based catalysts.Moreover,the excellent catalytic stability and durability of the Pd/RMγ-AlOOH and Pd/RMγ-Al_(2)O_(3) within 10 successive cycles of reduction enable the present industrial solid waste RM inducedγ-AlOOH andγ-Al_(2)O_(3) HPMSs as great promising Pd catalyst support for the reduction of the industrial wastewater containing 4-NP.

Near-infrared emissive AIE nanoparticles for biomedical applications:From the perspective of different nanocarriers

Fluorescent imaging based on near-infrared(NIR)fluorophores has revolutionized the techniques employed for detecting biological events in depth owing to their advantages referring to diminished photon scattering,high signal-to-noise ratio and better light transparence through tissue.As for conventional luminogens,the nanofabrication of those innately hydrophobicπ-conjugated architectures into water-dispersible nanoparticles(NPs)may result in attenuated fluorescent intensity deriving from the detrimental distribution ofπ-πinteractions in the confined space.Oppositely,chromophores possessing aggregation-induced emission(AIE)characteristics emit boosted brightness at aggregate level according to the mechanism of restriction of intramolecular motion(RIM).In this review,we summarize the recent progresses of NIR emissive AIE NPs for multifarious biomedical applications from the viewpoint of different fabricated manners,mainly covering self-assembly and matrices assisted approaches.Furthermore,the current challenges and future research directions of NIR AIE NPs are briefly discussed.

金属纳米团簇的合成及其光致发光性质的调控

金属纳米团簇是一种既具有出色光物理性质,又具有良好生物相容性的零维材料.利用配体对团簇的热力学稳定产物的选择性和还原剂动力学调控可以合成出结构多样的金属纳米团簇,在光学材料、生物医学和催化材料等领域展示出颇具潜力的应用前景.但金属纳米团簇的稳定性差、发光弱等缺点限制了其实际应用,因此通过聚集诱导发光效应和超分子自组装协同调控金属纳米团簇的稳定性及光学性质,可以构筑出结构与发光可控的金属纳米团簇组装体,有效促进金属纳米团簇的实际可用性.本文简要介绍了不同配体保护的金属纳米团簇的合成,阐述了金属纳米团簇的光致发光性质,总结了聚集诱导发光效应对团簇超分子组装体光致发光性质的影响规律,并分析提出了当前研究仍存在的问题及对未来探究的展望.

金属纳米团簇的超分子自组装及其应用

金属纳米团簇(NCs)是由几个至几千个金属原子通过物理或化学结合力组成的相对稳定的聚集体,其物理和化学性质具有量子尺寸依赖性.金属簇的尺寸可与电子的Ferimi波长相当,一般小于3 nm,具有异于对应体相块材的物化性质,如光学、电学、磁学、催化、手性等.基于自组装策略,将金属簇与不同类型的分子材料组装,不但可以实现金属簇的聚集诱导发光,而且还可以实现多功能的协调.结合本课题组的研究工作,本文综述了近期国内外相关研究,详细介绍了自组装对金属簇发光、组装结构的影响及金属簇组装体的应用等方面的研究进展.最后对金属簇的未来挑战和发展前景进行了展望.

Phytochemical-encapsulated nanoplatform for ＂ondemand＂ synergistic treatment of multidrug-resistant bacteria

Though phytochemicals are a promising alternative to traditional antibiotics for combating resistant bacteria, the low water solubility and lack of selectivity seriously hinder their widespread applications. Herein, we constructed a hyaluronidase-activated ＂on-demand＂ delivery nanocarrier to encapsulate plant essential oils （PEOs） for the synergistic treatment of mulfidrug-resistant bacteria. The bioavailability and selectivity of PEOs was enhanced and the antibacterial effect was significantly improved by combining with the photothermal effect of the nanocarrier. This antibacterial system was successfully applied for healing methicillin-resistant Staphylococcus aureus-infected wound with negligible cytotoxicity and biotoxicity in mice. Given the increasing risk of antibiotic resistance, we believe that this phytochemical-encapsulated nanoplatform would provide a long-term solution and be a new powerful tool for skin-associated bacterial infections.

Facile hydrothermal-thermal conversion synthesis of CaSiO_3 nanowires as promising structure and function integrated photoluminescent host candidate

A facile green low-cost controllable hydrothermal-thermal conversion(HTC) process for the uniform high aspect ratio CaSiO_3 nanowires has been developed using abundant CaCl_2·2H_2O and Na_2 SiO_3·9H_2O as raw materials without any organic additive. The nanowires exhibited a transparent characteristic from the ultraviolet to visible region, and the CaSiO_3:1.2%Tb^(3+)nanophosphors with well preserved 1D morphology demonstrated strong green luminescence with CIE coordinates of(x=0.3144, y=0.5912).The present work definitely reveals the nanowires as a promising structure and function integrated host candidate for green-emitting luminescent materials in light display systems and optoelectronic devices.

Incidence of Macrosomia in Rural Areas—Henan Province,China,2013–2017

Introduction:Macrosomia has short-term and long-term adverse health effects and is thus an important public health concern.Recent decades have witnessed increasing incidence of macrosomia in many countries.Methods:The present study used a large population-based birth cohort study to depict incidence of macrosomia among live births in rural areas of Henan Province of China from 2013 to 2017.Results:Among the 1,262,916 births,82,353 were cases of macrosomia.The overall incidence of all types of macrosomia,of macrosomia with birth weight<4,500 g,and of macrosomia with birth weight≥4,500 g were 6.52%,5.30%,and 1.22%,respectively.From 2013 to 2017,the incidence of macrosomia decreased by 31.3%from 7.96%in 2013 to 5.47%in 2017(X^(2)_(trend)=946.96,P_(trend)<0.001).Male infants and infants≥42 gestational weeks had significantly higher incidence of macrosomia than that of female infants and infants<42 gestational weeks(P<0.001).Conclusion:Gestational weight control through nutrition management and physical activities during pregnancy are needed to reduce incidence of macrosomia.

Is the Infuence of Chinese Local Government Act on Tourism Efficiency Positive?

In China,local governments play a very important role in the development of the tourism industry.Local governments appear to have a positive effect on the development of tourism because of the fact that the tourism industry output has improved for more than a decade.Many researchers have studied the relationship between government and tourism development.However,the existing studies were limited to qualtative discussion and there is still no relatively scientific quantitative analysis which can prove whether the impact is positive or not.Therefore,the purpose of this paper is to verify whether the impacts of Chinese local government act on the tourism industry are positive or negative from the perspective of efliciency.To achieve this aim,this paper binned a quantitative model of local govermment act,data envelopment analysis and spatial statistics together in a creative way,measured tourism industry eficiency with and without the influence of local government act and compared the changes in results and their spatial patterms and spatial interactions.On the basis of these analyses,the author found that positive impacts as a result of the local govermment act on eficiency in the tourism industy do exist.

Aggregation-enhanced theranostics:AIE sparkles in biomedical field

Theranostics referring to the ingenious integration of diagnostics and therapeutics has garnered tremendous attention in these years as it provides a promising opportunity for modern personalized and precision medicine.By virtue of the good biocompatibility,outstanding fluorescence property,easy processability and functionalization,promoted photosensitizing efficiency,as well as facile construction of multi-modality theranostics,fluorophores with aggregation-induced emission(AIE)characteristics exhibit inexhaustible and vigorous vitality in the field of theranostics.Numerous significant breakthroughs and state-of-the-art progression have been witnessed in the past few years.This review highlights the tremendous aggregation-enhanced superiorities of AIE luminogens(AIEgens)in disease theranostics mainly involving diagnostic imaging(fluorescence and room temperature phosphorescence),therapeutic intervention(photodynamic therapy),and feasibility in construction of multi-modality theranostics based on the experimental measurements and theoretical simulations.Additionally,the latest and advanced developments of AIEgens in disease theranostics in the aspect of corresponding strategies to design highly effective AIE-active theranostics through triggering aggregation formation are comprehensively summarized.Moreover,a brief conclusion with the discussion of current challenges and future perspectives in this area is further presented.