The lime-Cu2+-xanthate process is commonly used for the flotation separation of sphalerite from pyrite.In this process,lime is added to the pulp to inhibit the floatability of pyrite.However,the excessive use of lime can result in pipeline blockage and inadequate recovery of associated precious metals.Therefore,it is necessary to develop new flotation process that minimizes or eliminates the use of lime.In this paper,a novel Fe3+-Cu2+-butyl xanthate process was developed as an alternative to lime for separating of sphalerite from pyrite.The flotation results indicated that with the artificially-mixed minerals,the flotation recovery of pyrite was lower than 16%and that of sphalerite was higher than 47%at pH 5.0-10.0.The zeta potential measurements revealed that ferric ion preferred to adsorb on pyrite,and copper ion displaced with zinc ion from the lattice at the interface of sphalerite.The wettability analyses indicated that the hydrophobicity of sphalerite surface increased apparently after being treated with Fe3+-Cu2+-BX,while the hydrophobicity of pyrite surface remained nearly unchanged.With XPS analysis,Cu—S bond and hydrophilic ferric hydroxide were detected separately on the surface of sphalerite and pyrite after conditioning with Fe3+-Cu2+-BX,which facilitated the flotation separation of sphalerite from pyrite with butyl xanthate collector.

Helicenes are circularly polarized luminescence (CPL)-active but suffer from a fundamental tradeoff between fluorescence quantum yield (ΦF) and luminescence dissymmetry factor (|glum|). Herein, we present a strategy combining lateral π-extension and helical elongation in carbazole-embedded helicenes to address this challenge. Specifically, π-extended diaza[7]helicene (1) and diaza[9]helicene (2) were synthesized and characterized, revealing nearly a 2-fold increase in ΦF and a 6-fold enhancement in |glum| from 1 to 2. This approach offers a new pathway for high-performance CPL emitters.

A negatively curved aza-nanographene (NG) containing two octagons was synthesized by a regioselective and stepwise cyclodehydrogenation procedure, in which a double aza[7]helicene was simultaneously formed as an intermediate. Their saddle-shaped structures with negative curvature were unambiguously confirmed by X-ray crystallography, thereby enabling the exploration of the structure–property relationship by photophysical, electrochemical and conformational studies. Moreover, the assembly of the octagon-embedded aza-NG with fullerenes was probed by fluorescence spectral titration, with record-high binding constants ( K a =9.5×10 3  M −1 with C 60 , K a =3.7×10 4  M −1 with C 70 ) found among reported negatively curved polycyclic aromatic compounds. The tight association of aza-NG with C 60 was further elucidated by X-ray diffraction analysis of their co-crystal, which showed the formation of a 1 : 1 complex with substantial concave-convex interactions.

To effectively separte pyrite from chalcopyrite, tetrazine thione group and hydrocarbon chain were combined to synthesize tetrazine thione collectors. The flotation performance of tetrazine thione collectors on chalcopyrite and pyrite was investigated, and the influence of different hydrophobic groups on the flotation performance was revealed. UV tests indicated that HxMTT was easy to bond with Cu+ and Cu2+, which accompanied by the release of H+ into solution, while HxMTT was not easy to bond with Fe2+ and Fe3+. AFM and contact angle measurements implied that HxMTT adsorption on chalcopyrite increased the surface hydrophobicity of chalcopyrite. The results of FTIR indicated HxMTT chemisorption on chalcopyrite surface, and XPS analysis further indicated HxMTT chemisorption on chalcopyrite surface by Cu—N and Cu—S bonds.

The van der Waals (vdW) heterostructures employing graphene and hexagonal boron nitride (h-BN) have emerged as a typical system for building emergent two-dimensional devices, such as atomically thin transistors or capacitors. Herein, we study the nonlinear thermal transport in such vdW heterostructure by non-equilibrium molecular dynamics simulations. The results show that an obvious negative differential thermal resistance (NDTR) phenomenon can be observed under small temperature bias when the interlayer coupling becomes stronger. The vibrational spectra analysis manifests that the phonon filtering mechanism induced by interlayer coupling greatly hinders the interfacial thermal transport. To obtain the optimum conditions, the dependence of NDTR on the system length, lateral width, external temperature, and defect density is taken into account. Our findings extend the phonon filtering mechanism to thermal information processing.

We present the synthesis and characterization of the first triple oxa[6]helicene with C3 symmetry. In contrast to the reported D3-symmetric triple oxa[7]helicene, the C3-symmetric analogue holds parallel electric and magnetic transition dipole moments and thus enhanced luminescence dissymmetry, shedding light on the critical role of molecular symmetry on chiroptical response.

The synthesis of a class of contorted electron-deficient polycyclic aromatic hydrocarbons (PAHs) has been achieved by a one-pot bay annulation of perylene diimide involving a mild Suzuki coupling and subsequent air-mediated, ambient-light-induced photocyclization. X-ray crystallography unambiguously confirmed the contorted PAH structure bearing four imide groups. The photophysical and electronic properties of these contorted PAHs were also analyzed, showing a high fluorescence quantum yield of 86% and moderate electron mobility of 0.017 cm2 V-1 s-1.

Herein we present a synthesis of an S-shaped double helicene with fused imide moieties, achieving a contorted aromatic diimide (DHDI) with good fluorescence properties in both solution and the solid state. DHDI demonstrates distinct mechanofluorochromism from yellow to green emission under grinding of its crystalline powder.

Carbon foams (CFs) possess high storage capacity, good electronic conductivity and superb mechanical strength, which demonstrate promising applications in many engineering fields. Understanding thermal transport in CFs is critical for the design and reliability of functional electronic devices based on them. In this work, we systematically study anisotropic thermal transport in the CFs composed of sixfold-wing graphene nanoribbons by using equilibrium molecular dynamics simulations. The results showed that the remarkable anisotropic behavior reflecting geometric anisotropy can be attributed to the orientation-dependent group velocity of long wavelength phonons. Moreover, it is found that the anisotropic ratio could be effectively regulated by compress/tensile strains. Detailed spectral analysis revealed that the loading of strain would significantly modify the coupling level between the transverse and longitudinal vibrational modes, resulting in a change to the anisotropic ratio. For thermal management application, the interfacial thermal conductance (TBC) of CFs/silicon substrate is predicted to be about 35 MW/m2 K−1, which is comparable to the TBC of the transferred metal films on silicon or SiO2 substrates. Furthermore, the TBC could be further enhanced by increasing ambient temperature or external stress. Our results might provide guidance for the development of thermal interfacial materials and thermal channeling devices.

Herein, we propose a dual-responsive fluorescent nanoprobe to visualize the cross-talk between O2 and adenosine triphosphate (ATP) in living cells. We hope it will be a helpful tool for the further understanding of cellular metabolism and further facilitating risk warning in the process of adaptation to consistent environmental pressures in premalignant lesions.

Targeted delivery of antiobesity drugs to adipocytes presents a novel strategy for obesity treatment. The 11 beta-hydroxysteroid dehydrogenase type 1 (11 beta-HSD1) in adipose tissue is an attractive therapeutic target of obesity. Emodin (EMO) has been proven to be a potent and selective inhibitor of 11 beta-HSD1, but it frequently exerts low bioavailability owing to its poor water solubility and lack of tissue specificity. In this work, we conjugated a nanoscale drug delivery polymer with Adipo8 (Ap), a DNA aptamer with high affinity to mature white adipocytes, as a targeting modality that enabled selective delivery of emodin to adipocytes. Emodin-loaded PEG-PLGA nanoparticles (EMO-NPs) were formulated by a modified oil-in-water (O/W) emulsion solvent evaporation method, and Ap was covalently bound to the NP surface via the EDC/NHS method. The NPs were structurally investigated by TEM imaging, DLS and UV-VIS spectroscopy. The resulting aptamer-conjugated, emodin-loaded nanoparticles (Ap-EMO-NPs) had a spherical shape and an average particle size of 146.7 +/- 27.85 nm with a drug loading of around 6.8% and a sustained-release property. Confocal microscopy and flow cytometry demonstrated a significant increase in the internalization of Ap-EMO-NP in differentiated 3T3-L1 cells compared to EMO-NP functionalized with nonspecific aptamer. As confirmed by Oil Red O coloring, the Ap-EMO-NPs reduced lipid stacking in 3T3-L1 adipocytes in a sustained-release and dose-dependent manner. The results indicated that Adipo8-functionalized PEG-PLGA NPs could be a potential targeted therapeutic delivery vehicle for obesity treatment.

The modulation of solid surface properties via surfactants has a wide application in surface engineering. In this study, a novel S,O,O-ligand surfactant N-[(4-hydroxyamino)-4-butoxyl]-S-hexyl-dithiocarbamate (HABHTC) was first introduced to hydrophobize malachite surface. AFM morphology image clearly displayed that the dense HABHTC aggregates adsorbed on the whole surface of malachite, which increased its contact angle, decreased its surface energy, hydrophilicity index and interaction free energy with bubble. HABHTC exhibited stronger hydrophobization to malachite than calcite and quartz. FTIR and XPS recommended that HABHTC acted as a S,O,O-ligand to bond surface Cu atoms of malachite via building Cu-S and Cu-O bonds. The S,O,O-coordination enhanced the stability of Cu-HABHTC surface species on malachite and rendered HABHTC to possess better flotation specificity toward malachite versus calcite than octyl-hydroxamic acid (OHA). The C6H11-S-C=N-C3H6- configuration of HABHTC dramatically strengthened its hydrophobization toward malachite surface, resulted in a preferable hydrophobic flotation of malachite particles by using HABHTC as a collector.

The floatability of chalcopyrite and pyrite by using 6-hexyl-1,2,4,5-tetrazinane-3-thione (HTT) as a collector was evaluated in the paper. In comparison with the traditional-type collector sodium hexyl xanthate (SHX), HTT exhibited the favorable flotation affinity toward chalcopyrite and superior selectivity for flotation separation of chalcopyrite from pyrite. UV spectra demonstrated that HIT preferred to react with cupric/cuprous ions rather than ferric/ferrous ions. Contact angle results indicated a stronger hydrophobization of HTT towards chalcopyrite than SHX. DFT (density functional theory) calculations recommended that HTT had a stronger electron-acceptance power to the d-orbital electrons of interface copper atoms on chalcopyrite and a slightly weaker electron-donation ability than HX- anion, which improved the flotation selectivity of HTT toward chalcopyrite against pyrite. AFM images displayed a dense cover of HTT agglomerates on the whole surface of chalcopyrite. Zeta potential and XPS confirmed the bonding interaction of the interface copper atoms of chalcopyrite with the N and S atoms of HTT's tetrazinane-thione group.

ABSTRACT Developing specific flotation collectors to improve the separation and enrichment of copper oxide minerals from their ores is still a challenging job. In this article, a novel chelating collector, 5-(2,4,4-trimethylpentyl)-4-amino-1,2,4-triazolidine-3-thione (TMATT), was designed to separate and recover copper oxide minerals, and its flotation response to malachite, calcite, and quartz was compared with that of the traditional collector n-octyl hydroxamic acid (OHA). The findings of contact angle and micro-flotation indicated that TMATT exhibited stronger hydrophobization and better flotation performances to malachite than OHA, and also held the high flotation selectivity against quartz and calcite. The bench-scale flotation outcomes showed that TMATT achieved the high-efficient flotation separation and enrichment of copper oxide minerals from the mixed sulfide-oxide copper ore. XPS, FTIR, AFM, and zeta potential deduced that the adsorption of malachite toward TMATT was related to the reduction of surface Cu(Ⅱ) to Cu(Ⅰ) and the formation of TMATT-Cu(Ⅰ) surface complexes in which the exocyclic N and S atoms of TMATT bonded with the surface Cu(Ⅰ) on malachite. The superior hydrophobicity of TMATT-Cu(I) surface complexes in comparison to that of OHA-Cu(Ⅱ) surface complexes, the favorable five-membered ring bonding mode on malachite surfaces and the preferable chelating selectivity to soft acid Cu(Ⅰ) rather than to hard acid Ca(Ⅱ), deserved TMATT to possess better flotation response to malachite against calcite than OHA.

AIMS:To identify the target of an adipose specific aptamer adipo-8, predict the potential interaction between adipo-8 and its target, and investigate lipid-lowering effect of adipo-8 in vitro and in vivo. MAIN METHODS:Distinct membranous protein of 3T3-L1 adipocyte pulled-down by adipo-8 was mass-spectrometry analyzed as target candidate(s), and affinity of adipo-8 to target protein-silent adipocyte was detected to validate it. Interaction between adipo-8 and target was predicted by bioinformatic analysis, further confirmed by aptamer truncation and competitive binding assay. To investigate lipid-lowering effect of adipo-8 and mechanism behind, 250 nmol/L adipo-8 or library was incubated with 3T3-L1 adipocyte or target-protein-silent adipocyte for 24 h, and 0.01 μg/g/day adipo-8 or library was administrated to high-fat-fed male mice for 21 days. KEY FINDINGS:APMAP (Adipocyte Plasma Membrane Associated Protein) was identified as adipo-8 target, and adipo-8 affinity to adipocytes was in proportional to APMAP expression. Docking model between the stem-loop structure of adipo-8 and APMAP were predicted that adipo-8 was likely to interact with APMAP at its amino-acid 275-411 sequence. Moreover, adipo-8 could ameliorate fat deposition through interaction with APMAP in vitro, and administration of adipo-8 in high-fat-diet fed mice resulted in body weight loss and blood triglyceride decrease without liver or renal dysfunction. SIGNIFICANCE:Adipo-8 could recognize APMAP specifically and interact with its targets to ameliorate fat deposition in vitro and in vivo. Aptamer adipo-8 has potential to act as an effective and safe targeted drug for obesity and obesity related diseases.

Novel tetrazinan-thione compounds including 6-hexyl-1,2,4,5-tetrazinan-3-thione (HTT), 6-propyl-1,2,4,5-tetrazinan-3-thione (PrTT) and 6-phenyl-1,2,4,5-tetrazinan-3-thione (PhTT) were synthesized and originally introduced as collectors for beneficiation of copper oxide mineral. The micro-flotation investigations exhibited that HTT achieved higher malachite recovery with better flotation selectivity against calcite than octyl hydroxamic acid (OHA). The three tetrazinan-thione surfactants significantly improved the hydrophobicity of malachite surfaces as followed: HTT > PhTT > PrTT, matching well with their hydrophobic-hydrophilic index LogP value, as well as their flotation response to malachite. In-situ AFM images clearly presented that HTT firmly covered on malachite surfaces. Zeta potential suggested the chemisorption of malachite towards HTT. FTIR and XPS offered additional evidences that malachite chemisorbed HTT on to its surfaces where the Cu-S and Cu-N bonds were generated. The heptyl group possesses stronger hydrophobic than the hexyl group, while, HTT exhibited better hydrophobization towards malachite than OHA, which might be attributed to their different bonding mode on malachite surfaces.

Carbon/boron nitride heteronanotubes (CBNNTs) have attracted considerable attention owing to their unique properties and functions for practical applications in many fields. However, interfacial thermal transport in such heterostructures, which plays a pivotal role in determining their functional properties, is still unknown. In this work, we use non-equilibrium molecular dynamics (NEMD) simulations to study the thermal transport across CBNNTs interface. It is found that the heat flows preferentially from the BNNTs to the CNTs region, demonstrating pronounced thermal rectification (TR) effect. In addition, the TR ratio of zigzag CBNNTs is much more than that of armchair ones, especially under lager temperature bias. With the help of wave packet dynamics simulation and power spectrum calculation, the underlying mechanism of TR in CBNNTs is identified. Furthermore, the influence of system size, ambient temperature and defect density is studied to obtain the optimum conditions for TR. More importantly, we also found that the TR ratio of CBNNTs apparently decreases when taking account of the substrate interaction or tensile strain in practical design for thermal rectifier. Our results provide a certain guidance for designing high-efficiency thermal rectifier based CBNNTs.

Li metal batteries (LMBs) have been revived as promising rechargeable battery chemistry in the last few years due to their high potential energy densities. However, there is still a long way to go for commercialization of LMBs because of the limited cycle life and potential safety concerns of LMBs, which are caused by the formation of high surface (porous) Li and low Coulombic efficiency (CE) during repeated charge/discharge processes. Developing advanced electrolytes is crucial to develop practical LMBs with high energy density. In this work, we report a promising electrolyte approach based on the use of a new electrolyte solvent, which can be worked as the diluent for high concentrated electrolyte (HCE) to get a localized high concentrated electrolyte (LHCE). Although with an apparent salt concentration of 1M, this electrolyte generates salt decomposition dominant solid electrolyte interphases (SEIs) on Li metal anode, which is robust and conductive. Therefore, it shows high Li Coulombic efficiency and great stability in Li||NMC811 cells. The details together with post-cycling analysis will be discussed at the presentation.

环己烯具有活泼的双键,被广泛用于医药、农药、食品及其他高附加值精细化学品的生产中.工业上生产环己烯的方法主要有环己烷脱氢、环己醇脱水、卤代环己烷脱卤化氢、Birch还原和苯部分加氢等.相比于其他方法,苯部分加氢制环己烯工艺由于具有安全可靠、原子经济性强、环境友好等优点,引起了研究者的广泛关注.从热力学角度看,苯加氢生成环己烯的标准Gibbs自由能比生成环己烷的标准Gibbs自由能低75 kJ/mol,极不利于环己烯的生成.另外,苯环共轭大π键的化学性质较环己烯双键更稳定,在催化剂存在下环己烯极易深度加氢生成环己烷,反应难以停留在环己烯阶段.除引入水相外,催化剂是实现苯部分加氢制备环己烯工艺过程的关键,因此开发高活性、高选择性的催化剂显得格外重要.100多年前人们就开始探索苯部分加氢制环己烯工艺.自1957年Anderson在Ni膜催化苯加氢产物中检测到环己烯的存在以来,一些研究者陆续报道了钌催化剂催化的苯加氢反应,在苯转化率较低的情况下能检测到中间产物环己烯,并发现钌催化剂最适合该反应.其中,一项极为重要的研究进展是在含油相、水相、气相和固相的四相反应体系中,以过渡金属盐为添加剂,在剧烈搅拌下反应,环己烯收率可高达60％,提高了技术可行性.1989年日本旭化成公司率先实现了Ru-Zn催化苯部分加氢制环己烯工艺的工业化.1995年,我国神马集团引进日本旭化成苯部分加氢技术.随着技术的引进,国内各大科研院所、高校等的多个课题组相继加入苯选择加氢制环己烯催化剂的研究,研究工作主要集中在优化和完善催化反应条件、研制新催化剂、探索提高环己烯选择性的本质原因.近年来,大量文献报道通过合理设计Ru催化剂来提高环己烯选择性,如采用NaOH溶液对Ru/ZrO2催化剂进行锌刻蚀以增加催化剂表面羟基量,提高催化剂亲水性;又如通过添加合适的助剂La、Cu、Fe、Mn等对催化剂进行改性,从而提高反应选择性.虽然报道的催化剂体系很多,但目前国内工业化生产使用的均是传统Ru-Zn催化剂,且日本旭化成公司一直控制着催化剂的核心制备技术.本文介绍了苯部分加氢反应的反应机理、热力学特征及传质现象,着重概述了近年来苯部分加氢钌基催化剂的研究现状,包括催化剂前驱体、催化剂制备方法、载体、助剂以及添加剂对催化剂性能的影响,对现阶段研究存在的问题进行了总结,并展望了今后的发展前景.