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Since the launch of the policy of reform and opening up, the number of Chinese private enterprises has surged, and their social status has also continuously improved. This essay provides a perspective based on an investigation on private entrepreneurs in five cities in Zhejiang Province and Shanghai. Results show that, although private entrepreneurs achieved higher social status, most of them express deep concern for their security. Four main factors account for private entrepreneurs’ lack of security: difficulty in obtaining equal protection of private property; the risk of criminal charges that threaten personal safety; the growing culture of hatred against rich people; and doubts over changes on the state political ideology, the latter causing the most anxiety among entrepreneurs. This essay proves that, although the state regulates some private entrepreneurs in stages due to social justice pressures and to the need to ensure a stable governance, no overall ideology transformation may overturn the economic policies in the private sector.

Flexible supercapacitors with high areal energy density are promising energy storage devices to meet the increasing demands for wearable and portable electronic products. Herein, three kinds of flexible electrodes were fabricated electrochemically through tuning spatial distribution of graphene sheets composited with polyaniline (PANi) nanofiber array on carbon cloth, in which graphene sheets were used as the efficient growing substrate or protecting layer for the arrays and directly inserted into the arrays. It is found that the charge storage ability of all the PANi arrays could be enhanced significantly that depended greatly on the spatial distribution of graphene sheets composited with the array. The composite electrodes composing of graphene inserted PANi array on the graphene covered carbon cloth possesses the highest areal energy density among all the electrodes. More clearly, the corresponding all−solid−state supercapacitor devices can reach outstanding performances with a maximum energy density of 313 μWh cm−2 and capacitance retention of 92.7% after 5000 cycles could be achieved in the electrolyte containing Fe3+. This work is believed to provide a new thought for fabricating cost–effective and flexible electrodes with ultrahigh areal energy density, excellent flexibility and cycle stability endow for high−energy wearable/portable energy storage devices.

Two kinds of free–standing flexible hybrid electrode materials were fabricated through in situ hybridization of graphene oxides (GOs) onto polyaniline (PANI) nanofiber arrays grown on the surface of carbon cloth under high voltage electric field. The GOs introduced to the arrays could act as the growth sites or the top layer on the PANI arrays, depending on the spraying order of the GO before and after aniline. Great improvement in charge storage ability of PANI nanofibers could be achieved especially by using the GO as the substrate for the growth of the arrays. The PANI/GO/CC electrode showed a maximum areal capacitance of 1122.8 mF cm−2 at the scan rate of 5 mV s−1. Assembled with these electrodes, the all–solid–state symmetric supercapacitor could deliver a maximum energy density of 46.6 μWh cm−2 at a power density of 498.9 μW cm−2 with high capacitance retention of 94.1% and mechanical flexibility. The excellent capacitive performances could be ascribed to unique structural advantages of PANI nanofiber array enhanced by synergetic effect between PANI and graphene sheets. Such in situ hybridization could provide a facile and scalable route for fabricating high–performance free–standing flexible electrode materials for foldable and wearable devices.

This paper proposes a nonelliptic extended English teaching ability evaluation algorithm based on an adaptive random matrix model. The algorithm models a nonelliptical expansion target as multiple elliptical sub-objectives, and the expansion state of each sub-target is described by an inverse Wishart distribution. The new method is combined to improve the robustness problem caused by the initialization after the algorithm expansion. This research uses the smart teacher education platform to conduct research and analysis on the evaluation of teaching practice ability of intern normal students. From the perspective of data evaluation, we explore the influence of normal students’ curriculum training on the teaching practice ability of normal students. By analyzing the correlation between normal students’ course grades and practice grades, this paper explores the influence of normal students’ prepractice training on normal students’ teaching practice ability. This paper explores the influence of the training of normal students’ course learning on the teaching practice ability of normal students. The results show that the learning level of normal students’ professional courses has a significant impact on the development of normal students’ practice performance and teaching practice ability; the impact of normal students’ pedagogical course level on normal students’ practice performance and teaching practice ability is relatively low.

An effective approach for boosting oriented growth of polyaniline (PANI) arrays on carbon cloth (CC) is presented through spraying and in situ chemical polymerization under a high voltage electric ...

A facile approach for fabricating flexible electrodes was presented by using simultaneously commercial carbon cloth as three–dimensional conductive support and raw material source of graphene sheets through in–situ electrochemical exfoliation and re–deposition in same sulfate electrolyte system. The capacitive properties of carbon cloth were distinctly boosted through electrochemical treatment, which strongly depended on the nature of metal ions in the sulfate electrolyte. Moreover, the highest capacitive properties could be obtained for Li2SO4 among all the electrolyte systems, benefiting from thick and dense but porous graphene layers and high hydrophilic properties of the electrode. The assembled supercapacitor possessed large specific capacitance (292.8 mF cm−2 at 2 mA cm−2), high rate capability as well as high mechanical and cyclic stability. This approach has been demonstrated to be a simple and green route under mild condition for low–cost fabricating all–solid state supercapacitors with high charge storage ability.

Owning to the high toxicity and mobility of hexavalent chromium (Cr(VI)), the removal has caused tremendous attention recently. In this study, an obvious improvement on Cr(VI) removal can be achieved for polyaniline nanofibers (PANFs) by removing ammonia via heating treatment. The as-prepared PANFs manifest high removal capacity of 275.46 mg/g, being more than 10% and 50% increase compared to PANFs obtained without ammonia removal and general chemically synthesized particles. The excellent removal performances can be ascribed to the synergistic effect between uniform morphology, high specific surface area and good conductivity, which can provide large amount of active sites for Cr(VI) uptake. Benefiting from the easy control of morphology and structure as well as large–scale production, the present approach exhibits great promising to develop low–cost absorbents for removing heavy metal ions with high efficiency and multiple reuses to enhance their applicability on an industrial scale.

The control in morphology and microstructure is an efficient approach to regulate the gas sensing properties of the sensor. In this work, polyaniline (PANi) layer in nanoscale film morphology was coated on the surface of reduced graphene oxide (rGO) sheets through the in situ polymerization method. The microstructure and properties of the composite sheets were characterized by scanning electron microscopy, atomic force microscopy, Fourier transform infrared spectrometry, Raman spectrometry and thermal gravimetric analysis. It is found that there are strong effects of morphology-dependent structures of PANi layers on the sensing behaviors for ammonia detection, and more importantly, the utilization of the composite sheets as a new type of sensing material for highly sensitive detection of formaldehyde. Moreover, the best sensing properties can be achieved for the composite sheets with the thickness of PANi layer of 1.3 nm, benefiting from the strongest interaction between graphene sheet and PANi chains among all the composite sheets. Furthermore, a wide linear response range from 12 to 1500 ppm, 10 s response time for 100 ppm, 3.0 × 10−4/ppm sensitivity and 10 ppm detection limit can be achieved for ammonia, while 8 to 250 ppm, 35 s, 1.1 × 10−3/ppm and 4 ppm for formaldehyde. With the advantages in simplicity in material preparation and device operation as well as significant synergistic effects, PANi in nanoscale film morphology covered on the rGO sheets with large surface area can provide an efficient approach for fabricating sensitive and cheap chemiresistive sensor as an early warning system in some particular situations where either ammonia or formaldehyde is used widely or produced largely.

The nanofibrous morphology and chain orientation have predominant impacts on the charge storage ability of polyaniline (PANi) that could be promoted by introducing small molecules such as alcohols to affect the formation of the nanofibers. In this work, one kind of continuous–flow polymerization was designed to separate the seed formation and subsequently assembly process of PANi nanofibers, making it possible to evaluate independently the influence of isopropanol on the nucleation and growth of PANi nanofibers, i.e. isopropanol molecules were involving in the initial reaction in the flow polymerization, or only in the subsequent assembly and growth of nanofibrous seeds produced through flow polymerization. Furthermore, the effects of isopropanol content on the morphologies, microstructures and capacitance performances of PANi nanofibers were discussed. It is found that the isopropanol could give a great improvement in charge storage ability of the nanofibers when a small amount of alcohol molecules were only used for affecting the assembly and growth of PANi nanofibers. Benefiting relatively large diameter–to–length ratio and high conductivity, PANi nanofibers prepared at 5 wt. % content of isopropanol possessed the greatest specific capacitance of 1082 F g–1 at the scan rate of 1 mV s–1 and 530.2 F g–1 at the current density of 1 A g–1, which was improved by 10% compared with pure PANi. The understanding of effect of small organic molecules on the capacitance performances of PANi could provide a much easier route in fabricating high performance electrode of PANi as promising candidates for lightweight and flexible energy storage devices.

Large specific surface area and hierarchically porous structure play critical roles in the preparation of high–performance electrodes for supercapacitor that strongly depended on the morphologies of electroactive materials. To impart large specific surface area and high ionic permeability, three kinds of hierarchical micro/nanostructures, i.e. sea urchin–like, flower–like and carpenterworm–like nanostructures, of polyaniline (PANI) products were constructed through simple frozen interfacial polymerization without any templates, special chemical regents or organic solvents. The formation of hierarchical micro/nanostructured PANIs were significantly affected by the interfacial area between aniline and oxidant ice layers and the adding order of aniline and oxidant, more detailedly, the number of the nanofibrous seeds formed at the early stage of polymerization and their ambient aniline concentration as well as the release rates of aniline and oxidant. Furthermore, the PANI with sea urchin–like micro/nanostructure exhibited the highest charge storage ability among all the electrode materials, more clearly, the specific capacitance of 716.8 F g–1 at a current density of 1 A g–1, rate retention of 96.9% from 1 to 20 A g–1, and cycling retention of 73.6% after 2000 cycles. The remarkable electrochemical performance can be ascribed to unique self–assembly of highly ordered nanofibers, making it possible to give full play to the advantages of PANI nanofibers including large electrode/electrolyte contact area, high charge transport along the nanofibers, accommodate volume changes extending in every direction during cycling, and fast electron transport and ion diffusion through porous structure. It is believed that such interior design and eco–friendly fabrication can offer an effective strategy to promote the electroactive properties of the PANI, and further development in the sensor– and energy–related fields.

Polyaniline (PANI) nanobelts were efficiently prepared through template–free chemical polymerization by using ferric chloride and cumene hydroperoxide as the oxidation–reduction initiation system in the presence of a small amount of inorganic acids including sulfuric acid, phosphoric acid, hydrochloric acid and nitric acid. The influences of the nature of inorganic acids on the morphologies, microstructures and capacitive properties of PANI nanobelts were investigated by scanning electron microscopy, transmitting electron microscopy, atomic force microscopy, ultraviolet–visible spectroscopy, Fourier transform infrared spectroscopy, X–ray diffraction analysis as well as electrical and electrochemical measurements. It is found that although all products have ultrathin nanobelt morphologies with relatively high yield, their microstructure and properties were significantly sensitive to the existence of additional inorganic acids. Moreover, the specific capacitance of the nanobelts decreased according to the order of sulfuric acid, phosphoric acid, hydrochloric acid and nitric acid, and the largest specific capacitance of 584.1 F g–1 at the current density of 1 A g–1 with the specific capacitance retention of 77.21 % after 2000 cycles can be achieved by introducing sulfuric acid. Furthermore, the differences in the capacitances of the nanobelts are discussed based on capacitive and diffusion controlled contribution. These results show that a simple and green approach is proposed for bulk quantity production of PANI nanobelts without the use of any template in fully aqueous solution, and would also stimulate the exploration of applications of these nanobelts especially as promising electrode materials for energy storage devices.

Three kinds of polyaniline (PANI) nanofibers were prepared by introducing small alcohol molecules including methanol and ethanol as co-solvents into aqueous phase in the interfacial polymerization. The influences of alcohols on the morphology, microstructure, and electrochemical behaviors of PANI nanofibers were investigated by field emission scanning electron microscopy, ultraviolet-visible spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction analysis, as well as electrical and electrochemical measurements. It is found that the growth and migration of PANI nanofibers were obviously suppressed due to the hydrogen bonding between polymer chains and alcohol molecules. An improvement on the electrochemical performances could be achieved by adding alcohol molecules especially ethanol into aqueous medium. The specific capacitance was 1017, 1031, and 1042 F g−1 at the scan rate of 5 mV s−1 and 444, 463, and 489 F g−1 at the current density of 1 A g−1 for the PANI nanofibers prepared without alcohol as well as with methanol and ethanol, respectively. The increase in specific capacitance could be contributed to the formation of the nanofibers with larger length to diameter ratio and higher orientation of polymer chains, which could provide shorter ion diffusion path, enhance the electroactive regions, and increase the electrode/electrolyte contact area. This study therefore provides an efficient modified interfacial polymerization for fabricating PANI nanofibers with more desirable morphology and better energy storage performance.

The construction of polyaniline (PANI) chains in the interfacial polymerization was controlled by introducing isopropanol (IPA) as a co–solvent into aqueous phase. The influences of the IPA content on the morphology, microstructure and electrochemical behaviors of PANI products were investigated by field emission scanning electron microscopy, ultraviolet–visible spectroscopy, Fourier transform infrared spectroscopy, X–ray diffraction analysis as well as electrical and electrochemical measurements. It is found that the growth and migration of PANI molecules strongly depended on the IPA content through tuning the hydrogen–bonding strength between PANI chains and IPA molecules. With the increasing of the IPA content, the role of IPA played on the construction of PANI chains changed gradually from promoting the formation of PANI nanofibers to inhibiting the migration of PANI molecules into aqueous phase, which would result in more irregular shaped particles. Moreover, PANI electrode at the current density of 1 A g −1 reached its greatest specific capacitance of 539 F g −1 at 5% IPA content, with a secondary maximum of 475 F g −1 for 50% IPA content in aqueous phase, which were both higher than 444 F g −1 for the nanofibers prepared in the absence of IPA. It is demonstrated that a great enhancement on the capacitive properties can be achieved by introducing a small amount of IPA which would be of benefit to promote the formation of PANI nanofibers with larger ratio of height to diameter.

Polyaniline (PANI), thanks to low cost, easy synthesis, fast reversible Faradic reaction and especially theoretical charge storage capability, has been extensively studied in the field of energy conversion and storage. However, its development as electrode material in supercapacitor is still be restricted by the need of high–yield production of PANI with robust electrochemical performance. Herein, inspired by the seeding polymerization, and tunable conductivity and solubility with organic acid, one–pot bulk synthesis of PANI nanofibers in fully aqueous solution was realized with the aid of aniline oligomer and sulfonic acid. During the seeding polymerization process, four kinds of sulfonic acids with different functional groups and sizes including 5–sulfosalicylic acid (SSA), p–toluenesulfonic acid (pTSA), p–aminobenzenesulfonic acid (pASA) and camphorsulfonic acid (CSA) were introduced to efficiently control the assembly behavior of oligomers to form PANI nanofibers, meanwhile provide better electrical and electrochemical properties as well as good dispersion in aqueous solution compared with pure hydrochloric acid (HCl) medium. Benefiting from the bifunctional doping effects of sulfonic acid on the oligomer assembly and nanofiber dispersion, great enhancements on the electrochemical performances of PANI nanofibers can be easily achieved. Especially for CSA, high specific capacitance of 600.7 F g–1 at the current density of 1 A g–1 and good cycling stability with retention of 74% could be manifested, which are over 55% and 11% improvements in contrast to neat HCl medium, respectively. These results suggest that sulfonic acid assisted oligomer assembly is highly effective in combining smaller diameter of PANI nanofiber with superior supercapacitor property, and also provides a new strategy to promote the development of conductive polymers in energy related fields.

One kind of polyaniline (PANi)–based flexible electrodes for all–solid–state supercapacitor with ultrahigh areal capacitance and cycle stability is fabricated through electrochemical polymerization. The oriented growth of PANi nanofibers is efficiently promoted when graphene shell is firstly coated on carbon fiber. Then ferric sulfate is introduced into the electrolytes for further enhancing the pseudocapacitance contribution, and the best charge storage ability of the composite electrode is achieved at 15 mol. % Fe3+ ion content. The assembled supercapacitor possesses a maximum areal capacitance of 1.90 F cm−2 at the current density of 5 mA cm−2. At 30 mA cm−2, the device retained 74.7% of the maximum capacitance. It showed a maximum energy density of 264 μWh cm−2 at a power density of 2.5 mW cm−2 and a capacitance retention of up to 93.1% after 3000 cycles at 10 mA cm−2. These results can be attributed to high efficient pathway for ion diffusion and electron transport constructed between PANi nanofiber array and graphene shell on the CC, as well as the redox reaction in electrolyte and metal ion–doping effects of PANi caused by trivalent iron ions. Such device with the desirable characteristics has a promising application prospect in wearable power supply system.