An ultra-sensitive non-enzymatic hydrogen peroxide sensor based on SiO2-APTES supported Au nanoparticles modified glassy carbon electrode

A novel electrochemical sensor based on (3-aminopropyl)triethoxysilane (APTES) functionalized SiO₂ supported Au nanoparticles and Nafion (Nf) as the protective membrane was fabricated for the electrochemical determination of H₂O₂ in contact lens-cleaning solution. The modification steps of glassy carbon working electrode (GCE) were evaluated by electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). The amperometric results showed that Nf/[email protected]₂-APTES/GCE sensor can be used to determine H₂O₂ in contact lens solutions with the linear ranges of 14–180 μM and 0.18–7.15 mM, excellent sensitivities of 2514.6 and 894.2 μA mM cm^?2, and a low limit of detection (LOD) of 4.25 μM depending upon signal-to-noise ratio of 3. Nf/[email protected]₂-APTES/GCE exhibited excellent repeatability with relative standard deviation (RDS) of 2.66% and acceptable reproducibility with RSD of 3.35%. The sensor displayed reasonable selectivity in the presence of uric acid, dopamine, ascorbic acid, glucose, mannose, glycine, fructose, histidine, and arginine with RSD less than 2.5%. The fabricated Nf/[email protected]₂-APTES/GCE sensor has been successfully applied to detect H₂O₂ in contact lens cleaning solutions.     

Rational design of carbon shell-encapsulated cobalt nanospheres to enhance microwave absorption performance

Co@C core–shell nanospheres highly dispersed on carbon supports were rationally designed to improve the microwave absorbing property of the composite material, and fabricated by one pot thermal decomposition and simple annealing process. The Co nanospheres were completely encapsulated with thin carbon shells, which can effectively prevent the oxidation of the Co surface. Additionally, the particle size of Co nanospheres were properly controlled to optimize the electromagnetic property of the composite material. As a result, the lightweight Co@C/C composites with the particle size of 20 nm exhibited much enhanced microwave absorption properties. The improved microwave absorption performance is attributed mainly to the enhanced isotropic ratio and impedance matching of magnetic composites via tuning the Co particle size. Therefore, the welldesigned core-shell Co@C composite structure will provide a new insight for the development of high performance microwave absorbers.     

Fabrication and electrochemical properties of 3D nano-network LiFePO_4@multiwalled carbon nanotube composite using risedronic acid as the phosphorus source

LiFePO_4@multiwalled carbon nanotubes(LFP@MWCNTs) nanocomposite has been fabricated using risedronic acid(RDA) as a new eco-friendly phosphorus source. Microscopic, spectroscopic, and electrochemical characterization demonstrate that the MWCNTs are in the form of coiled and cross-linking nanoribbon, which wrapped and encrusted around LiFePO_4 particles to form a three-dimensional(3D) nano-network composite.This microstructure of 3D nano-network is obtained due to the reactions between RDA's special functional groups with Fe~(2+) and C-OH,-C=O or-COOH on the surface of the functionalized MWCNTs. The results also show that the particle size of the fabricated LiFePO_4@MWCNTs composite is below 300 nm with the pure crystal of olivine. This nanocomposite indicates an enhanced reversible capacity of 162.2 mAh g~(-1) at 0.2C, and high capacity retention of 76.5% even at 10C after the 800 th cycles. The electric conductivity and Li~+ diffusion coefficient(D_(Li)~+) of the LiFePO_4@MWCNTs are 3.79 × 10~(-2)S cm~(-1) and 4.46 × 10~(-11) cm~2s~(-1), respectively.These improved electrochemical parameters can be attributed to the nano-sized effect of particles, MWCNTs' wrapping effect and 3D nano-network microstructure of the LFP@MWCNTs resulted from using RDA as a new phosphorus source.     

Rapid point-of-use water purification using nanoscale zero valent iron (nZVI) particles

Nanoscale zero-valent iron (nZVI) particles are increasingly being investigated in removing aqueous contaminants. Here, we have demonstrated its inactivation and magnetic removal of bacteria and endotoxins from environmental wastewater samples. Varying dosages (10–1,000 μL) of 0–6 days aged nZVI with a concentration of 5 mg/mL for 2 mL wastewater samples were tested, and relevant removal efficiencies were determined using culturing method for bacteria and limulus amebocyte lysate (LAL) for endotoxins. The supernatants of wastewater samples after reacting with nZVI and subsequent magnetic separations were subjected to spectroscopic, qPCR and DGGE analysis. Overall, high magnetic bacterial removal efficiencies were observed up to 3–4 logs for 1 mL nZVI, while the removal efficiencies decreased sharply down to 0.5 log for 10 μL nZVI. qPCR and DGGE results revealed that higher dosages of nZVI caused severe bacterial cell membrane ruptures, releasing significant amounts of DNA up to 10⁷–10⁸ gene copies/mL when 1 mL nZVI was used. Richer DGGE patterns were observed for higher nZVI dosages. In addition, regardless of the dosages (10–1,000 μL) we have observed more than 90 % removal of endotoxins from the wastewater samples. The described technology has great promise to be used as a point-of-use water purification solution for various purposes.     

Microstructure/texture evolution maps to optimize hot deformation process of near-α titanium alloy

The microstructure/texture evolution(MTE,for short) map and processing map of a new near a titanium alloy Ti65 were constructed in order to investigate the workability and microstructure evolution of hot deformation.The processing map illustrated four domains,two summit domains and two instability domains.The morphologies of the a phase changed from the spheroidization(α+β region) to the deformed and elongated β grains(near the βtransus temperature T_β),and then to the obvious dynamic recrystallization(DRX)(β region) with the temperature rising from 930 ℃ to 1140℃.Deformation in the α+β field mainly generated the texture component with [0001]or [0223] parallel to radial directions(RDs).While deformation in the β phase field formed two types of texture component with [0001] parallel to RDs and [2110] parallel to compression direction.An optimized processing map was summarized by overlaying the macro-instability map on the original processing map,and the instability domain of Ti65 alloy was confirmed in the area with the strain rate higher than 0.01 s~(-1).     

糖蜜酒精废液脱钾树脂的解吸动力学

【目的】研究糖蜜酒精废液脱钾树脂BK-001中K~+的静态解吸过程。【方法】考察洗脱剂温度、浓度及树脂粒径对K~+解吸过程的影响,用动边界模型描述K~+的解吸过程。【结果】确定糖蜜酒精废液脱钾树脂BK-001中K~+的解吸过程为颗粒扩散控制,该反应的表观活化能为40.9kJ/mol,反应级数为1.19,表观频率因子为5.27×10~4 min~(-1),假二级动力学模型更适合描述K~+的解吸过程(R~20.995)。K+解析过程的总动力学方程式为1-3(1-F)~(2/3)+2(1-F)=5.27×104r20[H2SO4]~(1.19)e_((-4.09×10~4))/RT。【结论】脱钾树脂BK-001的解吸动力学方程为糖蜜酒精废液脱钾树脂的再生及钾盐资源的综合利用提供理论依据。     

龙匙片降血糖作用的实验研究

【目的】龙匙方是广西壮族自治区人民医院俞祝全医生的临床经验方,本文研究其对正常小鼠及几种糖尿病模型小鼠降血糖的作用。【方法】采用链脲佐菌素致糖尿病、肾上腺素致高血糖、大剂量口服葡萄糖致高血糖小鼠模型,分别观察龙匙片对正常和糖尿病模型小鼠血糖的影响。【结果】高、中剂量组(11500mg·kg~(-1)·d~(-1)、5750mg·kg~(-1)·d~(-1))龙匙片对链脲佐菌素致糖尿病、肾上腺素致高血糖、大剂量口服葡萄糖致高血糖小鼠的血糖具有明显的降低作用;但高、低剂量(11500mg·kg~(~(-1))·d~(-1)、3060mg·kg~(-1)·d~(-1))龙匙片对正常小鼠血糖水平均无明显影响(P0.05)。【结论】龙匙片对糖尿病模型小鼠具有降低血糖的作用。     

南宁至友谊关高速公路边坡植被枯落物特性研究

【目的】了解南宁至友谊关(简称南友)高速公路边坡绿化植被的水文效应。【方法】在全面踏查的基础上,选择了8个不同地点的7种典型群落类型,对其植被枯落物特性进行研究。【结果】三豆混播群落(S4)的枯落物蓄积量、吸水速率、有效拦蓄量均为最佳,分别为43.80t/hm~2、4 227g·kg~(-1)·h~(-1)、55.18t/hm~2,而木豆群落(S1)的枯落物最大持水量、最大持水率最高,分别达到2 832t/hm~2、283.2%。【结论】三豆混播群落是南友高速公路边坡植被类型中水土保持效应最均衡的群落配置,具有良好的生态水源涵养及保持的功能,可推广种植,以维护边坡植被和土壤的水文生态功能。     

鼠尾藻群体的有性生殖力影响因素研究

【目的】研究鼠尾藻(Sargassum thun bergii)有性生殖相关因子间的关系,分析鼠尾藻群体的有性生殖能力。【方法】通过统计分析方法,研究藻体长度与侧枝数、侧枝长度与生殖托数、生殖托长度与生殖托挂卵数间的关系。【结果】藻体长度与侧枝数、侧枝长度与生殖托数、生殖托长度与生殖托挂卵数间都为线性正相关,利用回归方程推算,1株成熟的鼠尾藻藻体能产生2×105~3.3×106个受精卵。【结论】1株成熟鼠尾藻的产卵量基本可满足1m2的采苗生产需要。     

涠洲岛西面及西南面沉积物重金属污染分析

【目的】研究广西涠洲岛海域沉积物污染情况并进行分析与评价。【方法】通过分析2014年涠洲岛沉积物重金属元素Cu、Pb、Zn、Cd、Cr含量水平,运用单因子评价法、潜在生态风险指数法和地累积指数法进行污染程度评价。【结果】涠洲岛西面及西南面海域沉积物重金属含量均值从小到大依次为CdCuPbCrZn,分别对应未检出、3.02 mg·kg~(-1)、3.19 mg·kg~(-1)、6.47 mg·kg~(-1)、10.10 mg·kg~(-1),含量范围分别为未检出、0.95~8.29mg·kg~(-1)、2.68~4.07mg·kg~(-1)、1.81~18.46mg·kg~(-1)、ND~34.59mg·kg~(-1)。重金属污染程度属于"低水平",单个及多种重金属生态风险分级均为"轻微",其中Cu是引发生态风险的主要元素,地累积指数亦表明该海域各重金属污染程度均为0级。【结论】总体来说,涠洲岛西面及西南面海域沉积物重金属含量与污染程度较广西沿海其他海域低,仍属清洁水平。     

污水排海工程渔业资源损害定量分析

【目的】以曹妃甸某污水排海工程为例,对排海工程渔业资源损害定量分析方法进行探讨,为今后类似工程生物资源损害评估提供参考依据。【方法】在大量已有研究成果及经验的基础上,对水污染生物资源损害计算基本公式、受损范围及死亡率的确定方法进行讨论。结合工程实际情况及海洋生态环境现状调查结果,定量分析工程对渔业资源造成的损害。【结果】工程对海洋渔业资源造成损害的面积约为0.218km2,在此范围内,仔鱼和鱼卵的损失量分别约为4.65×106尾和9.63×106个,而成鱼基本不受影响。【结论】本方法的提出对今后海洋工程生物资源损害研究具有一定的参考价值。     

发酵木糖高产乙醇树干毕赤酵母菌株的Co60诱变选育

【目的】选育能够利用木糖高产乙醇的酵母菌株。【方法】采用Co60诱变树干毕赤酵母(Pichia stipitis),筛选乙醇产量高的突变菌株,并对原始菌株、突变菌株的生长发酵特性和两个菌株对高浓度木糖、乙醇的耐受性进行比较。【结果】在YPX培养基上筛选获得1株能够高效发酵木糖的突变菌株1K-9。该菌株在50mL 15%FM发酵84h,发酵液乙醇含量最高达(51.034±0.112)g/L,比原始菌株提高10.05%;在500mL 15%FM发酵96h,乙醇含量最高达(51.390±0.119)g/L;在500mL 20%FM发酵156h,乙醇含量最高达(52.496±0.513)g/L。菌株1K-9在HSM培养基或含4%~5%乙醇的YPX培养基中生长良好,在含6%~7%乙醇的YPX培养基中生长缓慢。【结论】Co60诱变对于树干毕赤酵母(Pichia stipitis)菌株是有效的,能选育出木糖高产乙醇酵母菌株1K-9。     

防城港东湾纳潮量减弱及其影响分析

【目的】研究防城港东湾水交换改变状况,分析其变化的原因,并探讨造成的影响。【方法】采用传统方法计算防城港东湾2008年和2012年的纳潮量。【结果】2008年防城港东湾纳潮量为1.8443×108 m3,2012年纳潮量为1.7436×108 m3,仅4年时间防城港东湾纳潮减少量占总纳潮量的5.5%。纳潮量减少后海水交换能力明显减弱。【结论】港口码头工程填海和岸线及滩涂资源的大量利用减少了湾内海域空间面积,造成海水交换能力减弱,使湾内海洋生态环境出现退化现象。     

2015年秋季千里岩岛海域浮游植物群落结构特征

[目的] 为了了解千里岩岛附近海域浮游植物状况。[方法] 以2015年秋季在该海域的监测数据为基础,并结合2013年调查数据,分析该海域浮游植物的变化情况。[结果] 2015年秋季千里岩岛海域发现浮游植物37种,由硅藻和甲藻组成,平均密度为3.23×10⁵个/m³,监测区主要的优势种为圆筛藻(Coscinodiscus sp.)和虹彩圆筛藻(Coscinodiscus oculusiridis),多样性指数为2.13~3.42,平均为2.74。[结论] 与2013年调查数据比较,千里岩岛海域浮游植物种类数、密度和多样性指数有所增长,分析原因可能是由于调查季节不同。     

毛郁金乙醇提取物降血脂作用研究

【目的】研究毛郁金(Curcuma aromatica)乙醇提取物降血脂作用,为其综合开发利用提供依据。【方法】通过高脂饲料喂养及脂肪乳剂灌胃,建立高脂血症大鼠模型,连续3周给予毛郁金乙醇提取物进行治疗,设正常组、高脂模型组、辛伐他汀组和毛郁金乙醇提取物高、中、低剂量(生药18g·kg-1·d-1,12g·kg-1·d-1,6g·kg-1·d-1)组,以动物实验研究毛郁金乙醇提取物降血脂的作用。【结果】毛郁金乙醇提取物可降低大鼠血清总胆固醇(CHOL)、三酰甘油(TG)和低密度脂蛋白(LDL-C)的含量,并提高血清高密度脂蛋白(HDL-C)含量,对血清CHOL、LDL-C的降低作用:高中低剂量组,中剂量组对降低TG、升高HDL-C含量具有较好作用,毛郁金各给药组均对大鼠血清LDL-C含量有极显著降低作用。【结论】毛郁金乙醇提取物具有明显的降血脂作用。     

不同轮伐期巨尾桉人工林的经济效益分析

【目的】探讨不同轮伐期对人工林经济效益的影响,为从经济视角科学确定人工林的合理轮伐期提供理论依据。【方法】以短(7a)、中(13a)、长(21a)轮伐期的南亚热带巨尾桉人工林为研究对象,对不同轮伐期巨尾桉人工林的蓄积量(Stand volume,SV)、营林成本、净现值(Net present value,NPV)和内部收益率(Internal rate of return,IRR)进行分析,揭示不同轮伐期对经济效益的影响。【结果】随着轮伐期的延长,巨尾桉人工林的蓄积量持续增长,7a、13a、21a轮伐期的蓄积量分别为144.95m~3/hm~2、346.97m~3/hm~2、553.69m~3/hm~2。随着轮伐期的延长,巨尾桉人工林净现值不断增加,在12a时达到最高值(30 297.61元/hm~2),之后逐渐降低,7a、21a轮伐期的净现值分别为17 239.86元/hm~2、22 008.59元/hm~2。内部收益率在13a开始趋近峰值(53.32%),明显高于7a时的39.29%。【结论】在南亚热带,巨尾桉人工林的轮伐期确定在13a左右较为适宜,既可实现经济效益最大化,又可大幅提升蓄积量。     

高腐蚀条件下用铝合金材料腐蚀机理

铝合金具有低密度、低熔点、高比强度及优良的耐腐蚀性能等特点，被广泛用于航空航天、建筑、船舶等领域。在服役过程中，铝合金的表层氧化膜易受到环境中活性阴离子的破坏而发生腐蚀，对其性能造成严重的损害，故研究铝合金在高腐蚀性环境的腐蚀行为对工程选材具有非常重要的指导意义。选择6061铝合金、2195铝锂合金和7075铝合金为研究对象，对其在特定腐蚀介质中的腐蚀过程和力学性能进行分析，研究了铝合金在特定腐蚀介质中腐蚀形貌与力学性能的变化规律。结果表明：腐蚀初期，在高Cl^-、NO₂^3-、SO₂^4-离子浓度的腐蚀环境中，3种铝合金的氧化膜受到阴离子破坏后发生点腐蚀，使基体暴露在腐蚀环境中，进而发生电化学腐蚀，6061铝合金和2195铝锂合金腐蚀方式是由点腐蚀向面腐蚀转变，7075铝合金腐蚀方式为晶间腐蚀；经过腐蚀后6061铝合金能保持稳定的强度和塑性，7075铝合金和2195铝锂合金的强度和塑性都明显降低。     

不同轮伐期对巨尾桉人工林碳固存的影响

【目的】深入探讨不同轮伐期对巨尾桉人工林碳固存的影响,为从应对全球气候变化的视角确定合理轮伐期提供理论依据。【方法】以轮伐期为短(7a)、中(13a)和长周期(21a)的巨尾桉人工林为研究对象,通过对不同轮伐期桉树林分生物量、碳固存、年平均固碳量的分析,揭示不同轮伐期对桉树林分碳固存的影响。【结果】巨尾桉人工林的生物量碳随着轮伐期的延长而逐渐增加,由7a轮伐期的(75.81±5.12)t·C/hm~2增至13a轮伐期的(180.11±19.97)t·C/hm~2以及21a轮伐期的(192.08±16.50)t·C/hm~2,方差分析表明,13a和21a轮伐期的总生物量碳显著高于7a轮伐期,而13a和21a轮伐期之间的差异不显著。巨尾桉人工林土壤有机碳随轮伐期延长而显著降低,由7a轮伐期的(89.99±0.35)t·C/hm~2、13a轮伐期的(85.42±0.76)t·C/hm~2下降到21a轮伐期的(74.64±0.24)t·C/hm~2。7~13a仍是巨尾桉人工林固碳能力迅速增长期,年平均总生物量碳由7a时的10.78t·C/(hm~2·a)迅速提高到13a的19.54t·C/(hm~2·a),增长81%;21a时巨尾桉人工林进入固碳能力下降期,年平均总生物量碳降至3.78t·C/(hm~2·a),固碳能力只是13a的19.34%。【结论】在南亚热带,巨尾桉人工林的最佳轮伐期确定在13a左右较为适宜,这与经济效益的最大化一致。     

广西北海市的鸟类资源

【目的】对北海市鸟类资源进行全面调查分析。【方法】于2005—2016年对广西壮族自治区北海地区的鸟类进行调查,结合查阅历史资料文件记载,归纳总结全市的鸟类资源。【结果】在北海地区共记录鸟类455种,留鸟种类均较少,多数鸟类在北海为候鸟,其中国家一级重点保护鸟类3种,数量均极为稀少,国家重点保护动物69种,包括数量众多的隼形目猛禽。【结论】北海是西伯利亚、东亚、东北亚候鸟迁往西太平洋群岛、东南亚、南亚以及非洲大陆的重要通道和停歇地。北海地区候鸟数量众多,但由于内陆和滨海湿地退化,以及盗猎野生鸟类行为导致大型水鸟在该地区缺失。因此需在春秋两季迁徙季节加强候鸟保护工作。     

龙江河春季浮游植物群落特征及其富营养化评价

【目的】针对2013年春季广西龙江河河段拉浪水库上游爆发的大规模大薸和水葫芦现象,对龙江河流域的浮游植物进行调查。【方法】运用生物多样性指数和营养状态指数对龙江河的营养状态进行评价。【结果】本次调查浮游植物共镜检到7门42属56种(变种),其中绿藻门和硅藻门的种类较多,分别占镜检种类数的37.50%和25.00%。龙江河流域中的拟多甲藻丰度水平最高,其细胞密度为0.12×106~5.13×106 cells·L-1,其中糯米滩水电站的甲藻丰度占比高达91.76%,发生较严重的甲藻水华。龙江河流域的浮游植物多样性指数(H′)为0.68~2.99,均匀度指数(J)为0.18~0.48,营养状态指数为42.10~53.60。【结论】调查期间龙江河处于中营养和轻度富营养化水平。