1 Introduction

Because long-term drinking of nitrophenol- contaminated water is harmful to human health, it is important to remove nitrophenols from water[1-2]. Up to now, several methods were utilized to remove nitrophenols from water, such as biodegradation, adsorption, electrochemical oxidation, and heterogeneous photocatalytic oxidation[3]. Among these methods, heterogeneous photocatalytic oxidation is regarded as one of the most promising techniques for wastewater treatment[4-5].

调压井开挖及一次支护全部完成后，为了避免和隧洞交叉施工，待完成剩余的隧洞开挖后，从隧洞内自下而上进行调压井混凝土二次衬砌。

Titanium dioxide (TiO2) has captured considerable attention due to its high physico- chemical stability, non-toxicity, low cost, and high photocatalytic activity[6-10]. However, the photocatalytic activity only works under UV light irradiation due to its wide band gap (Eg=3.0-3.2eV), the solar energy conversion efficiency is very low, and the recombination rate of photogenerated electrons and holes is fast, which limit its practical applications[11-12]. Dye sensitization is an effective method to raise the visible-light photocatalytic activity of TiO2, but the application of dye-sensitized TiO2 is still restricted due to dye degradation during the photocatalytic process[13-14].

Up to now, conductive polymers with extended π-conjugated electron systems have drawn extensive attention due to their high mobility of charge carriers, high absorption coefficients, high conductivity, effective electron donors and good electron transporters[15-19]. Polypyrrole (PPy) and polyaniline (PANI) are popular conductive polymers due to their high conductivity and excellent environmental stability, and has been used as stable photosensitizers to enhance their solar energy transfer, electronic conductivity and photocatalytic activities of TiO2[20-21].

（二）科技馆从业人员参与职称评定存在较大难度。由于科技馆行业缺乏自有统一的职称体系，都是走的其他专业技术职称系列。各馆职称评定的情况各不相同，目前只能“靠”在现行专业技术职称系列上参加评审与聘任。根据笔者了解，多数科技馆员工根据工作性质和各自情况选择“馆员系列”和“工程师系列”等作为其职称发展通道的较多。如笔者工作的浙江省科技馆挂靠的是群文馆员系列。

Conductive polymer composites exhibit catalytic and sensing properties better than those of neat conductive polymers. Our previous study indicated that conductive polypyrrole-polyaniline/TiO2 nanoparticles (PPy-PANI/TiO2) showed higher photocatalytic activity than that of polypyrrole/TiO2 (PPy/TiO2) and polyaniline/TiO2 (PAIN/TiO2) under visible-light illumination.

The powder-form photocatalysts are difficult to be separated and recovered from solution, thus hinder their practical application. Therefore, it is essential to immobilize photocatalysts on some substrates. However, after immobilization the photocatalytic activity of TiO2 usually decreases[22].

1990年，我国将环境保护纳入基本国策。在2017年10月，党的“十九大”提出了加强生态保护的方针政策，对建设美丽中国予以规划。在2018年6月16日，国务院发布了《关于全面加强生态保护坚决打好污染防治攻坚战的意见》，从重要性、指导思想、问政考核、治理体系等方面出发，对全国环境执法监测工作予以部署。由此可见，积极贯彻落实环境执法监测工作成为当务之急。文中以县级市为对象，对如何推动这一工作进行探讨。

2 Experimental

2.1 Materials

Titanium foil (99.8%, 0.3mm thick) was supplied by Aldrich (Milwaukee, WI). 4-nitrophenol (4NP) was purchased from Shanghai Fine Chemical Co., Ltd. (Shanghai, China). Sodium fluoride was purchased from Tianjin Tongxin Chemistry Co., Ltd. (Tianjin, China). Acetone was obtained from Shanghai Kefeng Chemistry Co., Ltd. (Shanghai, China). Sodium bisulfate, sulfuric acid, and absolute alcohol were supplied by Shantou Xilong Chemical Co., Ltd. (Shantou, China). Pyrrole (99% purity) were supplied by Aladdin Chemistry Co., Ltd. (Shanghai, China). Sodium sulfate was purchased from Chemical Plant of Hubei University (Wuhan, China). Aniline (99.5% purity) was purchased from Shanghai Zhanyun Chemistry Co., Ltd. (Shanghai, China). All the reagents were analytically pure, and were not puried. Water was purified by a Milli-Q water system (Bedford, USA).

2.2 Preparation of TiO2 nanotube arrays

[10] 景茂祥, 颜远瞻, 平昱航, 李立康. 介孔二氧化钛微球光催化剂的结构与性能[J]. 材料科学与工程学报, 2014, 32(1): 5～9.

2.3 Preparation of PPy-PANI/TiO2 NT, PANI/TiO2 NT and PPy/TiO2 NT

PPy-PANI/TiO2 NT was prepared by CV scans between -0.4 and +1.0V for three scans with a scan rate of 50 mV/s. A three-electrode system was used with a carbon electrode as counter electrode, a KCl-saturated calomel electrode (SCE) as reference electrode, and TiO2 NT as working electrode. The solution contains 0.5 mol/L H2SO4, 0.5mol/L Na2SO4, 0.05mol/L aniline, and 0.15mol/L pyrrole. After CV experiments, the films were washed and dried, and are denoted hereinafter as PPy-PANI/TiO2NT.

For comparison PANI/TiO2 NT and PPy/TiO2 NT composites were prepared and processed in parallel. Synthesis of PANI/TiO2 NT was performed in the solution containing 0.2mol/L aniline, 0.5mol/L H2SO4 and 0.5mol/L Na2SO4. PPy/TiO2 NT was synthesized in the solution containing 0.2mol/L pyrrole, 0.5mol/L H2SO4 and 0.5mol/L Na2SO4.

2.4 Characterization

The crystal structure of products was characterized using an automatic X-ray diffractometer with Cu Kα (Rigaku, Japan). The morphology and chemical elements of TiO2 NT and PPy-PANI/TiO2 NT were obtserved by scanning electron microscopy (SEM, Shimadzu, Japan) with energy dispersive spectroscopy (EDS, Shimadzn, Japan). Fourier transform infrared (FTIR) spectroscopy (Bruker, Germany) was also employed to do further characterization.

2.5 Photoelectrochemical measurements

All the electrochemical experiments were carried out on a CHI660C Electrochemical Workstation (Shanghai Chenhua Instrument Corporation, China). A three-electrode system was used with a carbon electrode as counter electrode, a KCl-saturated calomel electrode (SCE) as reference electrode, PPy-PANI/TiO2 NT, PANI/TiO2 NT and PPy/TiO2 NT as working electrode, and 0.5mol/L Na2SO4 as supporting electrolyte. A 300W xenon lamp with a 400nm cutoff lter was utilized as visible-light source. The applied voltage was 0 V. All the potentials were respect to SCE.

2.6 Measurements of photocatalytic activities

Photocatalytic activity of PPy-PANI/TiO2 NT, PANI/TiO2 NT and PPy/TiO2 NT was evaluated by degrading 10mg/L 4NP aqueous solution under the irradiation of a 300W xenon lamp with a 400nm cutoff lter. 1 piece of PPy-PANI/TiO2 NT, PANI/TiO2 NT or PPy/TiO2 NT was placed in 60mL of 4NP aqueous solution and stirred in the dark for 30min, the concentration of 4NP was determined and referred as the initial concentration C0. The 4NP solution was illuminated by visible light under continuous stirring. The 4NP solution was sampled at intervals of 15min, and was analyzed by a 754 UV-vis spectrometer at a wavelength of 320nm. The concentration of 4NP was determined by a calibration curve (Fig.1). The linearity range of 4NP was found between 0 and 12mg/L with correlation coefficient of 0.9998.

Fig.1 Calibration curve of 4NP solution

3 Results and discussion

3.1 XRD analysis

Fig.2 XRD patterns of TiO2 NT and PPy-PANI/TiO2 NT composites

FTIR spectra of PANI/TiO2, PPy/TiO2 and PPy-PANI/TiO2 nanocomposites were shown in Fig.4. The peaks of PANI/TiO2 at 1299 and 1520cm-1 are attributed to C-N and C=C, respectively. In case of PPy/TiO2, the characteristic absorption peaks located at 1116 (C-N stretching mode), 1588 (C=C stretching mode) and 1027cm-1 (pyrrole aromatic ring). The absorption peaks of PPy-PANI/TiO2 located 1308 (C-N stretching mode), 1589 (C=C stretching mode) and 1121cm-1 (pyrrole aromatic ring) indicate that the copolymer of pyrrole and aniline was deposited on TiO2 NT successfully.

3.2 Morphology of TiO2 NT and PPy-PANI/TiO2 composites

The SEM images of TiO2 NT and PPy-PANI/TiO2 NT composites were shown Fig.3. TiO2 NT was composed of uniform, well-ordered, and vertically oriented TiO2 nanotubes with pore size of about 90nm and wall thickness of about 20nm (Fig.3a). In case of PPy-PANI/TiO2 NT, the walls of TiO2 NT are unevenly covered PPy-PANI copolymer.

4.注重企业金融会计队伍建设。金融会计风险要想控制在一定的范围内，就先要建立完善的体系，强化参与人员的专业技能和基本素质，创建一支专业化的队伍，不仅在专业技能上要过硬，思想素质和个人觉悟上也要够强，只有这样，在外来诱惑面前才能抵御住。所以在培训方面也要对从业人员进行定期的教育，不仅仅是专业技能上的，还有思想道德上的。其次在人员的招聘上，也有制定严格的招聘制度，不用品德有问题的人，对于各方面都胜任的人员进行培养，同时岗位之间要进行划分，各个岗位间的职责要明确。

Fig.3 SEM images of (a) TiO2NT and (b) PPy-PANI/TiO2 NT composite

3.3 FTIR analysis

XRD patterns of TiO2 NT and PPy-PANI/TiO2 NT are shown in Fig.2. The characteristic peaks of Ti were shown in the the XRD patterns as reference. Besides the characteristic peaks of Ti foil, the diffraction peak at 2θ=25.3° was indexed to (101) planes of anatase TiO2 (PDF#21-1272), indicating that anatase TiO2 was formed, and the PPy-PANI copolymer does not change the crystalline structure of TiO2.

Fig.4 FT-IR spectra of PANI/TiO2, PPy/TiO2 and PPy-PANI/TiO2 nanocomposites

3.4 EDS analysis

Energy dispersion spectroscopy (EDS) was utilized to analyze the of element composition (Fig.5). Because TiO2 NT was synthesized by anodization in a mixture solution containing NaHSO4 and NaF, there are some residue elements, such as F, Na and S in the energy dispersion spectroscopy of PPy-PANI/TiO2 NT. Moreover, N, O, Ti were present, confirming the formation of PPy-PANI/TiO2 NT.

Fig.5 EDS of PPy-PANI/TiO2 NT composite

3.5 Photocurrent response

Fig.6 Transient photocurrent-time curves of (a) PPy-PANI/TiO2 NT, (b) PPy/TiO2 NT (c) PANI/TiO2 NT and (d) pure TiO2 NT electrodes under visible light irradiation

[8] Wang P,Yap P S,Lim T T. C-N-S Tridoped TiO2 for Photocatalytic Degradation of Tetracycline Under Visible-light Irradiation[J]. Applied Catalysis A: General, 2011, 399(1): 252～261.

3.6 Photocatalytic activity of pure TiO2 NT, PPy/TiO2 NT, PANI/TiO2 NT and PPy-PANI/TiO2 NT under visible-light irradiation

Fig.7 Kinetic data for the degradation of aqueous 4NP on pure TiO2 NT, PPy/TiO2 NT, PANI/TiO2 NT and PPy-PANI/TiO2 NT under visible light irradiation

Fig.7 shows the photocatalytic activity of pure TiO2 NT, PPy/TiO2 NT, PANI/TiO2 NT and PPy-PANI/TiO2 NT by monitoring the degradation of 4NP solution. The regression curve of natural logarithm of normalized 4NP concentration versus reaction time was a straight line, demonstrating that the photocatalytic degradation of 4NP followed pseudo-rst order kinetics:

(1)

where C0 and Ct are the concentration of 4NP (mg/L) at t=0 (min) and any time t (min), and k is the reaction rate constant (min-1). The rate constant of 4NP degradation over photocatalysts decreases in following order: PPy-PANI/TiO2 NT>PPy/TiO2 NT>PANI/TiO2 NT>pure TiO2 NT, indicating that PPy-PANI/TiO2 NT composites exhibited the highest photocatalytic activity.

4 Conclusion

The PPy-PANI/TiO2 NT was synthesized by cyclic voltammetry technique. The photocurrent of PPy-PANI/TiO2 NT composites about is more than two times as high as that of the TiO2 NT, indicating the efficient separation of photogenerated electron-hole pairs of PPy-PANI/TiO2 NT. PPy-PANI/TiO2 NT exhibited the highest photocatalytic activity among pure TiO2 NT, PPy/TiO2 NT and PANI/TiO2 NT under visible-light irradiation.

Reference

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In this study, polypyrrole-polyaniline copolymer/TiO2 NT (PPy-PANI/TiO2 NT) were synthesized by cyclic voltammetry (CV) technique. The morphology, crystalline structure, optical properties, and photocatalytic activities of PPy-PANI/TiO2 NT were investigated. PPy-PANI/TiO2 NT not only exhibits high photocatalytic activity under visible-light irradiation, but also can be recovered from solution easily.

Fig.6 shows the photocurrent of TiO2 NT and PPy-PANI/TiO2 NT composites when light was turned on and off. The photocurrent of PPy-PANI/TiO2 NT composites and TiO2 NT was 52 and 21μA, respectively. The photocurrent results indicate the efficient separation and transfer of photogenerated electron-hole pairs in PPy-PANI/TiO2 NT.

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Titanium foils (0.3mm thickness, 10mm×30mm) were cleaned ultrasonically in acetone and ethanol, respectively, followed by washed with deionized water. Ti foil was anodized using a DC power supply in an electrolyte of 0.5mol/L NaHSO4 and 0.1mol/L NaF at 15V for 2h. The resulting TiO2 NT was heated at 500℃ for 2h to form anatase.

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作为生育制度的重要组成部分之一，产假制度既涉及广大女性职工个人、家庭和全体社会成员的切身利益，又关系到国家、社会乃至全人类的人口可持续发展，必须引起我们的重视。我国历来重视对女职工生育权益的保护，已在《劳动法》和《女职工劳动保护特别规定》等对产假进行了相关规定。然而，产假制度在具体实施中仍然存在着地区时间差异、制度设计不完善、监管不力等问题，引发了社会争议。造成我国产假制度存在上述问题的原因是多方面的。因此，笔者认为，解决这一问题既要立足于当前我国的国情与体制，又要注意与国际接轨，还要在实践过程中不断与时俱进，使其越来越人性化，以促进产假制度的更好落实。

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国内高校旅游管理专业中，重点本科院校以理论学习为主，旅游管理专业所涉及的管理类课程较多，专业课程也基本以基础课为主，注重培养学生的学术科研思维，培养学生的管理能力，实践环节所占的比重比较低，缺少实习过程，如华东师范大学、厦门大学等。招收普通本科的院校基本都采取了理论学习与实践相结合的方式，人才培养方案当中实践教学所占比重在30%左右，多数学校采用“理论学时+实验学时”的课程安排，注重实习尤其是顶岗实习的作用，让学生走进企业，直接参与企业的生产管理活动，如临沂大学、潍坊学院等。

[15] Nuraje N, Su K, Yang N, Matsui H. Liquid/Liquid Interfacial Polymerization to Grow Single Crystalline Nanoneedles of Various Conducting Polymers[J]. ACS Nano, 2008, 2(3): 502～506.

[16] Hong S Y, Park S M. Electrochemistry of Conductive Polymers 36. Ph Dependence of Polyaniline Conductivities Studied by Current-sensing Atomic Force Microscopy[J]. The Journal of Physical Chemistry B, 2005, 109(19): 9305～9310.

[17] Karim M R, Lim K T, Lee C J, et al. Synthesis of Core-shell Silver-Polyaniline Nanocomposites by Gamma Radiolysis Method[J]. Journal of Polymer Science Part A: Polymer Chemistry, 2007, 45(24): 5741～5747.

第二，宽松的货币政策容易加剧企业过度投资、削弱投资不足问题；而紧缩的货币政策则能抑制过度投资问题、加剧投资不足，并且这些影响对国有企业尤为明显。

高压直流输电系统直流滤波器接地故障机理分析//莫品豪,郑超,程骁,张晓宇,吕航,文继锋//(20):171

2.2 两组新生儿指标比较 观察组新生儿出生体质量、巨大儿4例(5.00%)，对照组分别为(3.81±0.73)kg和15例(18.75%)，差异有统计学意义(t=-8.33，P=0.02；χ2=21.60，P=0.00)；两组新生儿窒息率均为2.50%(2/80)，差异无统计学意义(χ2=1.31，P=1.24)。

[18] Karim M R, Lee H W, Cheong I W, et al. Conducting Polyaniline-Titanium Dioxide Nanocomposites Prepared by Inverted Emulsion Polymerization[J]. Polymer Composites, 2010, 31(1): 83～88.

（6）适时给予评价。每个学生由于生活经历、环境及对文化的感受等因素的不同，在学习中表现的特征也不一样，有人善于表达，有人善于操作等，因此在学生的学习过程中，对学生表现出来的行为家用加以适当的评价，可以帮助学生认识自我，建立信心。什么样的教学行为可以给学生带来激励性的评价，是老师每节课关心的问题，不要只停留在“你回答很好”这样的口头表扬上，对不同层次的学生采取不同的方式。学生在自主、探究、合作过程出现的意见、观点、情感、态度，教师要适时给予引导、包容和鼓励。教师不仅仅是学生的鼓励者，更应该是学生的欣赏者，通过教师的言语、神情、赞许的目光来激发学生的学习兴趣。

每年汛前，县防汛抗旱指挥部利用召开全县防汛抗旱工作会议的时机，对各乡镇行政首长进行业务培训。各乡镇结合实际，对各村支书、主任及各机关单位干部职工进行防汛业务培训，作防汛纪律要求。建立健全由县武警、县消防、县公安、县武装、县水利等9支共120人的防汛抢险应急队伍，并开展防汛技能培训。2008—2012年，平塘县除举办11次规模较大防汛技能培训，受训达1000余人次，大部分参训人员都能掌握操作冲锋舟的技能和基本抢险技术外，还在重点山洪灾害易发多发区域开展山洪灾害应急演练。

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[22] Souzanchi S, Vahabzadeh F, et al. Performance of an Annular Sieve-plate Column Photoreactor Using Immobilized TiO2 on Stainless Steel Support for Phenol Degradation [J]. Chemical Engineering Journal, 2013, 223: 268～276.

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2016年以来，房地产估价行业进入综合化、信息化发展阶段。2016年7月通过评估行业的基本大法《资产评估法》，奠定了评估行业的法律地位，为维护各方的合法权益提供了法律依据，降低了人才的进入门槛，为行业发展注入新活力。同时，在“互联网+”供给侧结构性改革的宏观背景下，传统的房地产估价业务受到一定影响，行业走进了必须与时俱进地创新服务对接新需求的时代［2］。

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[25] 谭志谋, 王慧洁, 杨杭生,张孝彬. 阳极氧化法制备二氧化钛纳米管阵列的形貌[J]. 材料科学与工程学报, 2013, 31(3): 390～394+385.

[26] 王月勤, 陶杰, 何娉婷. 二氧化钛纳米管上电沉积羟基磷灰石[J]. 材料科学与工程学报, 2007, 25(2): 249～252.

例如：《黄河怨》（光未然词，洗星河曲）这首著名女高音独唱曲，恨与悲痛之情控诉，揭露日本帝国主义在中国土地上犯下的滔天罪行。有这样的一种历史画意，让歌唱者想象她此时身临其境的那种感觉，所以由声乐教育家郭淑珍演唱了《黄河怨》给观众留下了深刻难忘的印象。