Numerical Research of Fluid Flow and Solute Transport in Rough Fractures under Different Normal Stress

The effects of roughness and normal stress on hydraulic properties of fractures are significant during the coupled shear flow test. Knowing the laws of fluid flow and solute transport in fractures is essential to ensure the nature and safety of geological projects. Although many experiments and numerical simulations of coupled shear flow test have been conducted, there is still a lack of research on using the full Navier-Stokes (N-S) equation to solve the real flow characteristics of fluid in three-dimensional rough fractures. The main purpose of this paper is to study the influence of roughness and normal stress on the fluid flow and solute transport through fractures under the constant normal stiffness boundary condition. Based on the corrected successive random addition (SRA) algorithm, fracture surfaces with different roughness expressed by the Hurst coefficient (H) were generated. By applying a shear displacement of 5 mm, the sheared fracture models with normal stresses of 1 MPa, 3 MPa, and 5 MPa were obtained, respectively. The hydraulic characteristics of three-dimensional fractures were analyzed by solving the full N-S equation. The particle tracking method was employed to obtain the breakthrough curves based on the calculated flow field. The numerical method was verified with experimental results. It has been found that, for the same normal stress, the smaller the fracture H value is (i.e., more tough the fracture is), the larger the mechanical aperture is. The ratio of hydraulic aperture to mechanical aperture (eh/em) decreases with the increasing of normal stress. The smaller the H value, the effect of the normal stress on the ratio eh/em is more significant. The variation of transmissivity of fractures with the flow rate exhibits similar manner with that of eh/em. With the normal stress and H value increasing, the mean velocity of particles becomes higher and more particles move to the outlet boundary. The dispersive transport behavior becomes obvious when normal stress is larger

Immunization coverage, knowledge, satisfaction, and associated factors of non-National Immunization Program vaccines among migrant and left-behind families in China: evidence from Zhejiang and Henan provinces

Abstract Background Migrant and left-behind families are vulnerable in health services utilization, but little is known about their disparities in immunization of non-National Immunization Program (NIP) vaccines. This study aims to evaluate the immunization coverage, knowledge, satisfaction, and associated factors of non-NIP vaccines among local and migrant families in the urban areas and non-left-behind and left-behind families in the rural areas of China. Methods A cross-sectional survey was conducted in urban areas of Zhejiang and rural areas of Henan in China. A total of 1648 caregivers of children aged 1–6 years were interviewed face-to-face by a pre-designed online questionnaire, and their families were grouped into four types: local urban, migrant, non-left-behind, and left-behind. Non-NIP vaccines included Hemophilus influenza b (Hib) vaccine, varicella vaccine, rotavirus vaccine, enterovirus 71 vaccine (EV71) and 13-valent pneumonia vaccine (PCV13). Log-binomial regression models were used to calculate prevalence ratios (PRs) and 95% confidence intervals (CIs) for the difference on immunization coverage of children, and knowledge and satisfaction of caregivers among families. The network models were conducted to explore the interplay of immunization coverage, knowledge, and satisfaction. Logistic regression models with odds ratios (ORs) and 95% CIs were used to estimate the associated factors of non-NIP vaccination. Results The immunization coverage of all non-NIP vaccines and knowledge of all items of local urban families was the highest, followed by migrant, non-left-behind and left-behind families. Compared with local urban children, the PRs (95% CIs) for getting all vaccinated were 0.65 (0.52–0.81), 0.29 (0.22–0.37) and 0.14 (0.09–0.21) among migrant children, non-left-behind children and left-behind children, respectively. The coverage-knowledge-satisfaction network model showed the core node was the satisfaction of vaccination schedule. Non-NIP vaccination was associated with characteristics of both children and caregivers, including age of children (> 2 years-OR: 1.69, 95% CI: 1.07–2.68 for local urban children; 2.67, 1.39–5.13 for migrant children; 3.09, 1.23–7.76 for non-left-behind children); and below caregivers’ characteristics: family role (parents: 0.37, 0.14–0.99 for non-left-behind children), age (≤ 35 years: 7.27, 1.39–37.94 for non-left-behind children), sex (female: 0.49, 0.30–0.81 for local urban children; 0.31, 0.15–0.62 for non-left-behind children), physical health (more than average: 1.58, 1.07–2.35 for local urban children) and non-NIP vaccines knowledge (good: 0.45, 0.30–0.68 for local urban children; 7.54, 2.64–21.50 for left-behind children). Conclusions There were immunization disparities in non-NIP vaccines among migrant and left-behind families compared with their local counterparts. Non-NIP vaccination promotion strategies, including education on caregivers, and optimization of the immunization information system, should be delivered particularly among left-behind and migrant families. Graphical Abstrac

Lanthanide Amido Complexes Incorporating Amino-Coordinate-Lithium Bridged Bis(indolyl) Ligands: Synthesis, Characterization, and Catalysis for Hydrophosphonylation of Aldehydes and Aldimines

Two series of new lanthanide amido complexes supported by bis­(indolyl) ligands with amino-coordinate-lithium as a bridge were synthesized and characterized. The interactions of [(Me₃Si)₂N]₃Ln^III(μ-Cl)­Li­(THF)₃ with 2 equiv of 3-(CyNHCH₂)­C₈H₅NH in toluene produced the amino-coordinate-lithium bridged bis­(indolyl) lanthanide amides [μ-{[η¹:η¹:η¹:η¹-3-(CyNHCH₂)­Ind]₂Li}­Ln­[N­(SiMe₃)₂]₂] (Cy = cyclohexyl, Ind = Indolyl, Ln = Sm (<b>1</b>), Eu (<b>2</b>), Dy (<b>3</b>), Yb (<b>4</b>)) in good yields. Treatment of [μ-{[η¹:η¹:η¹:η¹-3-(CyNHCH₂)­Ind]₂Li}­Ln­[N­(SiMe₃)₂]₂] with THF gave new lanthanide amido complexes [μ-{[η¹:η¹-3-(CyNHCH₂)­Ind]₂Li­(THF)}­Ln­[N­(SiMe₃)₂]₂] (Ln = Eu (<b>5</b>), Dy (<b>6</b>), Yb (<b>7</b>)), which can be transferred to amido complexes <b>2</b>, <b>3</b>, and <b>4</b> by reflux the corresponding complexes in toluene. Thus, two series of rare-earth-metal amides could be reciprocally transformed easily by merely changing the solvent in the reactions. All new complexes <b>1</b>–<b>7</b> are fully characterized including X-ray structural determination. The catalytic activities of these new lanthanide amido complexes for hydrophosphonylation of both aromatic and aliphatic aldehydes and various substituted aldimines were explored. The results indicated that these complexes displayed a high catalytic activity for the C–P bond formation with employment of low catalyst loadings (0.1 mol % for aldehydes and 1 mol % for aldimines) under mild conditions. Thus, it provides a convenient way to prepare both α-hydroxy and α-amino phosphonates

Additional file 1 of Immunization coverage, knowledge, satisfaction, and associated factors of non-National Immunization Program vaccines among migrant and left-behind families in China: evidence from Zhejiang and Henan provinces

Additional file 1: Questionnaire. immunization coverage, knowledge and satisfaction of non-NIP vaccines

Novel Lanthanide Amides Incorporating Neutral Pyrrole Ligand in a Constrained Geometry Architecture: Synthesis, Characterization, Reaction, and Catalytic Activity

The first series of lanthanide amido complexes incorporating a neutral pyrrole ligand in a constrained geometry architecture were synthesized, and their bonding, reactions, and catalytic activities were studied. Treatment of [(Me₃Si)₂N]₃Ln­(μ-Cl)­Li­(THF)₃ with 1 equiv of (<i>N</i>-C₆H₅NHCH₂CH₂)­(2,5-Me₂C₄H₂N) (<b>1</b>) afforded the first example of bisamido lanthanide complexes having the neutral pyrrole η⁵-bonded to the metal formulated as [η⁵:η¹-(<i>N</i>-C₆H₅NCH₂CH₂)­(2,5-Me₂C₄H₂N)]­Ln­[N­(SiMe₃)₂]₂ (Ln = La (<b>2</b>) and Nd (<b>3</b>)). Reaction of [(Me₃Si)₂N]₃Sm­(μ-Cl)­Li­(THF)₃ with 2 equiv of <b>1</b> produced the complex [η⁵:η¹-(<i>N</i>-C₆H₅NCH₂CH₂)­(2,5-Me₂C₄H₂N)]­[η¹-(<i>N</i>-C₆H₅NCH₂CH₂)­(2,5-Me₂C₄H₂N)]]­SmN­(SiMe₃)₂ (<b>4</b>). Treatment of <b>3</b> with 2 equiv of <b>1</b> gave the sandwich neodymium complex [η⁵:η¹-(<i>N</i>-C₆H₅NCH₂CH₂)­(2,5-Me₂C₄H₂N)]₂Nd­[η¹-(<i>N</i>-C₆H₅NCH₂CH₂)­(2,5-Me₂C₄H₂N)] (<b>5</b>), in which two neutral pyrroles bonded with metal in an η⁵ mode. Complex <b>5</b> could also be prepared by reaction of [(Me₃Si)₂N]₃Nd­(μ-Cl)­Li­(THF)₃ with 3 equiv of <b>1</b>. Reactivities of the lanthanide bisamido complexes were further investigated. Reaction of complex <b>2</b> with pyrrolyl-functionalized imine [2-(2,6-^<i>i</i>Pr₂C₆H₃NCH)­C₄H₃NH] afforded a mixed η⁵-bonded neutral pyrrole and η¹-bonded anionic pyrrolyl lanthanum complex [η⁵:η¹-(<i>N</i>-C₆H₅NCH₂CH₂)­(2,5-Me₂C₄H₂N)]­{η¹-2-[(2,6-^<i>i</i>Pr₂C₆H₃)­NCH]­C₄H₃N}­La­[N­(SiMe₃)₂] (<b>6</b>). Reactions of complexes <b>2</b> and <b>3</b> with pyrrolyl-functionalized secondary amine afforded the mixed η⁵-bonded neutral pyrrole and the η¹-bonded anionic pyrrolyl lanthanide complexes [η⁵:η¹-(<i>N</i>-C₆H₅NCH₂CH₂)­(2,5-Me₂C₄H₂N)]­[(η¹-2-^<i>t</i>BuNCH)­C₄H₃N]₂Ln (Ln = La (<b>7</b>), Nd (<b>8</b>)) with dehydrogenation of the secondary amine. Investigation of the catalytic properties of complexes <b>2</b>–<b>8</b> indicated that all complexes exhibited a high activity with a high chemo- and regioselectivity on the addition of dialkyl phosphite to α,β-unsaturated carbonyl derivatives. An interesting result was found that 1,2-hydrophosphonylation substrates could be catalytically converted to 1,4-hydrophosphinylation products when the substrates are the substituted benzylideneacetones by controlling the reaction conditions

Synthesis, Characterization, and Reactivity of Lanthanide Amides Incorporating Neutral Pyrrole Ligand. Isolation and Characterization of Active Catalyst for Cyanosilylation of Ketones

A series of lanthanide amido complexes incorporating a neutral pyrrole ligand were synthesized and characterized, and their catalytic activities were studied. Treatment of [(Me₃Si)₂N]₃­Ln­(μ-Cl)­Li­(THF)₃ with 1 equiv of [(2,5-Me₂C₄H₂N)­CH₂CH₂] ₂NH (<b>1</b>) in toluene afforded the corresponding lanthanide amides with the formula [η⁵:η¹-(2,5-Me₂C₄H₂N)­CH₂CH₂]₂­NLn­[N­(SiMe₃)₂]₂ (Ln = La (<b>2</b>), Nd (<b>3</b>)). Reaction of <b>2</b> or <b>3</b> with <i>N</i>,<i>N</i>′-dicyclo­hexyl­carbo­diimide (CyNCNCy) gave the carbodiimide selectively inserted into the appended Ln–N bond products formulated as CyNC­{[<i>N</i>,<i>N</i>-(2,5-Me₂C₄H₂N)­CH₂CH₂]₂N}­NCyLn­[N­(SiMe₃)₂]₂ (Ln = La (<b>4</b>), Nd (<b>5</b>)). Reactions of the lanthanide amides with Me₃SiCN were also examined. A mixed reaction of [(Me₃Si)₂N]₃­La­(μ-Cl)­Li­(THF)₃, [(2,5-Me₂C₄H₂N)­CH₂CH₂]₂NH (<b>1</b>), and Me₃SiCN in toluene at room temperature produced the novel cyano bridged dinuclear lanthanum complex η⁵:η¹:η³-[(2,5- Me₂C₄H₂N­CH₂CH₂)₂N]­La­[N­(SiMe₃)₂]­(μ-CN)­La­[N­(SiMe₃)₂]₃ (<b>6</b>). The stoichiometric reactions of lanthanide amides <b>2</b> or <b>3</b> with Me₃SiCN produced the novel trinuclear lanthanum and neodymium complexes {(η⁵:η¹-[(2,5-Me₂C₄H₂­NCH₂CH₂)₂N]­Ln­[N­(SiMe₃)₂]­(μ-CN)}₃ (Ln = La (<b>7</b>), Nd (<b>8</b>)) through selective σ-bond metathesis reaction of the terminal Ln–N (N­(SiMe₃)₂) bond with the Si–C bond of Me₃SiCN. On the basis of the stoichiometric reactions of complexes <b>2</b>, or <b>3</b> with Me₃SiCN, complexes <b>2</b>, <b>3</b>, <b>4</b>, <b>5</b>, <b>7</b>, and <b>8</b> as catalysts for cyanosilylation of ketones were investigated. Results indicated that these complexes displayed a high catalytic activity on addition of Me₃SiCN to ketones, and the activity of the complexes has the order of <b>7</b> ∼ <b>8</b> > <b>2</b> ∼ <b>3</b> ∼ <b>4 ∼ <b>5</b></b>. Thus, complex <b>7</b> or <b>8</b> was proposed as the active catalyst in the catalytic reaction for the precatalysts of <b>2</b> and <b>3</b>

Synthesis and Characterization of Organolanthanide Complexes with a Calix[4]-pyrrolyl Ligand and Their Catalytic Activities toward Hydrophosphonylation of Aldehydes and Unactivated Ketones

The alkali metal salt free dinuclear trivalent lanthanide amido complexes (η⁵:η¹:η⁵:η¹-Et₈-calix­[4]-pyrrolyl)­{LnN­(SiMe₃)₂}₂ (Ln = Nd (<b>2</b>), Sm (<b>3</b>), Gd (<b>4</b>)) were prepared through the silylamine elimination reactions of calix[4]-pyrrole [Et₂C­(C₄H₂NH)]₄ (<b>1</b>) with 2 equiv of [(Me₃Si)₂N]₃Ln­(μ-Cl)­Li­(THF)₃ (Ln = Nd, Sm, Gd) in toluene at 110 °C. The complexes were fully characterized by elemental, spectroscopic, and single-crystal X-ray analyses. Studies on the catalytic activity of the new lanthanide amido complexes revealed that these complexes can be used as efficient catalysts for hydrophosphonylation of aldehydes and unactivated ketones, affording the products in high yields by employing a low catalyst loading (0.1 mol %) at room temperature in a short time (20 min). Noteworthy is that it is the first application of calix[4]-pyrrolyl-supported lanthanide amides as catalysts to catalyze the hydrophosphonylation of aldehydes and unactivated ketones under mild conditions

Synthesis and Characterization of Organolanthanide Complexes with a Calix[4]-pyrrolyl Ligand and Their Catalytic Activities toward Hydrophosphonylation of Aldehydes and Unactivated Ketones

The alkali metal salt free dinuclear trivalent lanthanide amido complexes (η⁵:η¹:η⁵:η¹-Et₈-calix­[4]-pyrrolyl)­{LnN­(SiMe₃)₂}₂ (Ln = Nd (<b>2</b>), Sm (<b>3</b>), Gd (<b>4</b>)) were prepared through the silylamine elimination reactions of calix[4]-pyrrole [Et₂C­(C₄H₂NH)]₄ (<b>1</b>) with 2 equiv of [(Me₃Si)₂N]₃Ln­(μ-Cl)­Li­(THF)₃ (Ln = Nd, Sm, Gd) in toluene at 110 °C. The complexes were fully characterized by elemental, spectroscopic, and single-crystal X-ray analyses. Studies on the catalytic activity of the new lanthanide amido complexes revealed that these complexes can be used as efficient catalysts for hydrophosphonylation of aldehydes and unactivated ketones, affording the products in high yields by employing a low catalyst loading (0.1 mol %) at room temperature in a short time (20 min). Noteworthy is that it is the first application of calix[4]-pyrrolyl-supported lanthanide amides as catalysts to catalyze the hydrophosphonylation of aldehydes and unactivated ketones under mild conditions