97 research outputs found

    Study on the contamination and source of chromium in the sea worm jelly in Xiamen

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    目的了解厦门市市售土笋冻中铬的污染状况,探讨土笋冻中铬的污染来源及预防措施。方法 2012—2014年在厦门市各采样点随机抽取土笋冻样品81份,虫体样品9份,从宁德地区滩涂海域采集可口革囊星虫、淤泥、海水等环境样品6份,依照GB/T 5009.123—2003《食品中铬的测定》中推荐的石墨炉原子吸收光谱法测定样品中铬的含量。结果 81份土笋冻样品中铬含量范围在0.024~17.6 mg/kg之间,平均值为2.17 mg/kg,中位数为1.33 mg/kg,超标率为42.0%(34/81)。添加明胶加工后导致土笋冻中铬含量从1.33 mg/kg升至5.35 mg/kg。从宁德地区滩涂海域采集的星虫、淤泥、海水样品中铬的含量范围分别为2.67~2.70、68.5~77.9和0.038~0.046 mg/kg。结论厦门市市售土笋冻样品中铬的污染情况较为严重,监管部门须加强对土笋冻的原料、加工、销售过程的监控,保证食品安全。Objective To investigate the chromium contamination of sea worm jelly in Xiamen market and to propose the preventive measures against chromium contamination of sea worm jelly based on analysis of the source.Methods A total of 81 samples of sea worm jelly and 9 samples of polypide were collected in Xiamen market from 2012-2014 and 6 samples of Phascolosoma esculenta,silt and seawater were collected from Ningde.The concentrations of Cr in the samples were determined by graphite furnace atomic absorption spectrometry according to GB/T 5009.123-2003.Results The chromium content of 81 samples were 0.024-17.6 mg/kg,the average content was 2.17 mg/kg,and the median was 1.33 mg/kg.The qualified rate was 58.0%.The concentration of Cr in sea worm jelly was changed from 1.33 to 5.35 mg/kg after adding gelatin.The contents of Cr in the Phascolosoma esculenta,silt and seawater from Ningde area were 2.67-2.70,68.5-77.9,0.038-0.046 mg/kg,respectively.Conclusion The chromium contamination in the sea worm jelly was severely in Xiamen.Supervision and monitoring on the raw materials,production,sales of the sea worm jelly should be strengthened to ensure food safety.福建省卫生计生系统食品污染物及有害因素监测方案(闽卫法监函[2014]128号

    Protograph-based LDPC decoder applied to magnetic recording channel

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    针对传统原模图低密度奇偶校验(lOW dEnSITy PArITy CHECk,ldPC)码在译码硬件实现中,由于采用随机扩展方式,导致数据拥塞和布线困难,继而产生译码延时和资源消耗的提高及吞吐量的下降问题,通过2步准循环扩展得到了适于硬件实现的码字结构,设计了一种面向磁记录信道的原模图ldPC码译码器。该译码器信息更新采用基于TdMP(TurbO dECOdIng MESSAgE PASSIng)分层译码的归一化MIn-SuM算法使得译码器具有部分并行架构;同时为了降低译码时间及功耗,给出一种低资源消耗的提前终止迭代策略。硬件实现结果表明,该译码器的译码性能十分接近相应的浮点算法,在低资源消耗的前提下,工作频率可达183.9 MHz,吞吐量为63.3 MbIT/S,并可同时适用于多种原模图ldPC码。Using random expansion algorithm,the hardware implementation of conventional protograph-based LDPC(low density parity check) decoders has difficulty with wiring and data transmission,which results in the improvement of resource consumption and decrease in throughput.In this paper,an easy-hardware-implementation quasi cyclic protographbased LDPC code is obtained by the use of a two-step lifting procedure,and we also propose a protograph-based LDPC decoder for magnetic recording channels.Utilizing the normalized Min-Sum algorithm based on the TDMP(Turbo decoding message passing) layered decoding scheme,the proposed decoder has a partially parallel architecture.Moreover,an early termination strategy is also proposed to reduce the latency and power consumption of the decoder.The proposed LDPC decoder is evaluated on a Xilinx Spartan 6 FPGA(field programmable gate array) platform and the results indicate that the proposed decoder requires low resource and can be utilized for multiple protograph-based LDPC codes.国家自然科学基金(61271241)~

    Assessment of impact of intensive livestock cultivation on water environment in mountain and hilly areas of South China

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    [摘要]选择南方山地丘陵区典型规模畜禽养殖集中地为研究区域, 通过对该研究区域周边地表水及地下水的 调查采样, 分析主要污染物时空变异及污染物形态之间的变化, 并对周边水环境进行初步评价。结果表明: 规模化畜禽养殖区域的浅层地下水和地表水已经受到严重污染; 养殖场的环保处理设施与养殖规模不配套 造成大量污染物进入地表水环境; 生物氧化塘的护堤和塘底未经防渗处理, 造成下游地下水污染; 养殖场排 放的污水经厌氧和好氧生物处理后富含有机质、氨氮、可溶态有机磷, 利于作物吸收和生长, 应尽量循环使 用。指出由于养殖污水变化较大, 为避免二次环境污染, 必须处理达标后结合配方施肥技术按需回用农田。[Abstract]By selecting a typical site of intensive livestock cultivation in a mountain area of South China as the study area, and investigating and sampling surface and groundwater in the study area, the spatial and temporal variat ions of the main pollutants and changes among pollutant forms were analyzed. The environmental effects of intensive livestock cultivation on surrounding water environments were evaluated. The results indicated that the shallow groundwater and surfacewater were heavily contaminated in the intensive livestock cultivation area. Large amounts of the pollutants entered the surface water, due to the fact that the wastewater treatment facility did not match the scale of livestock cult ivation. The lack of liner treatment of the bank and liner of the lagoon resulted in groundwater pollution. The effluent wastewater from the culturing farm after anaerobic and aerobic biologic treatment was full of organic matter, ammonia nitrogen, and dissolved organic phosphorus, which aided the growth of plants and should be recycled. Because of the significant change of the wastewater component, and in order to avoid secondary pollution, the wastewater should be recycled to land combined with precision fertilizer formula technology after treatment to bring it to the standard.福建省重大科技项目(2002H009);福州大学人才基金项目(XRC-0611

    Treatment of was tewater from jeans production by hydrolytic acidification /biological contact oxidation /sedimentation

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    [摘要]:针对牛仔衣染色( 以靛蓝染料为主) 废水色度较高、有毒性及污染严重的特点, 确定采用水解酸化/生物 接触氧化/沉淀的工艺处理该废水。在丽发制衣厂的应用实践表明: 该工艺切实可行, 运行费用低, 处理效果稳定, 出 水水质达到DB 44 /26—2001 中一级排放标准, COD、BOD5、SS、色度去除率分别达到94%、92%、87%、83%。[Abstract]:The wastewater fromjeans production(mainly containing indigo dyeing) is characterized by higher colourity, toxicity and severe pollutant. With the consideration of these special characters, the wastewater is treated by hydrolysis acidification /biological contact oxidation /sedimentation process. The operation in Lifa Clothing Manufacture demonstrates that this process is feasible. Its running cost is low and the treatment results are stable. Finally, it also shows that the treated effluent quality accords with the requirement of Ⅰclass standard of water pollutant discharge extreme(DB 44 /26—2001) in Guangdong province. Its COD, BOD5, SS and colourity removal rate reach 94%, 92%, 87% and 83% respectively.海南省自然科学基金资助项目( 80673

    Study on polychlorinated biphenyl congeners and organochlorine insecticides in Daya Bay

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    1999年 8月 4日采集了大亚湾次表层水、悬浮颗粒物和表层沉积物并用气相色谱 (电子捕集检测器 )分析了其中 12个多氯联苯 (PCBs)和 18个有机氯农药样品。总PCBs含量 ,水体中介于 91.1~ 135 5 .3ng/L ,沉积物中为 (0 .85~ 2 7.37)× 10 -9;总HCHs含量水体中介于 35 .5~ 12 2 8.6ng/L ,沉积物中则为 (0 .32~ 4 .16 )×10 -9;总DDTs含量在水体中介于 2 6 .8~ 975 .9ng/L ,沉积物中为 (0 .14~ 2 0 .2 7)× 10 -9;而在悬浮颗粒物中均未检出。水体和沉积物中DDT/(DDE +DDD)比值较大 ,表明近期仍有此类化学物质输入大亚湾海域。本研究为大亚湾养殖海区提供难降解有机污染物的现状资料。Samples at sub surface water, suspended particulate matter (SPM) and surface sediment collected from Daya Bay in Aug.4, 1999 have been analysed for 12 polychlorinated biphenyl (PCB) congeners and 18 organochlorine insecticides, using gas chromatography with electron capture detection. Total PCBs levels varied from 91.1 ng/L to 1 355.3 ng/L in water and from 0.85×10 -9 to 27.37×10 -9 (dry weight) in sediment. The levels of total hexachlorocyclohexanes in water varied from 35.5 ng/L to 1 228.6 ng/L, whilst in sediment they ranged from 0.32×10 -9 to 4.16×10 -9 (dry weight). None of the target compounds were detected in SPM. For the sum of dichlorodiphenyltrichloroethanes (DDTs), their levels were in the range 26.8~975.9 ng/L water, and (0.14~20.17)×10 -9 (dry weight) in sediment. The higher ratios of DDT/(DDE+DDD) in water and sediment in showed such chemicals will influx into the bay. Current contamination status of persistent organic pollutants was offered in the aquacultural area of Daya Bay.中国科学院大亚湾海洋生物综合实验站基金资助项目 (S96 0 9);; 广东省创新百项资助项目 (2KB0 6 70 1S

    Evaluation and Fate of the Organic Chlorine Pesticides at the Waters in Jiulong River Estuary

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    1999 0 6,对九龙江口 1 5个站位的表层水 ,1 3个站位的间隙水进行了 1 8种有机氯农药的测定结果表明 ,有机氯农药总含量在表层水中的浓度范围为 51 3~ 2 4 79ng L ;在间隙水中的浓度范围是 2 66~ 33355ng L .对不同有机氯的含量在各站位的分布特征进行了探讨 ,发现Methoxychlor(甲氧滴涕 ) ,EndosulfanSulfate(硫酸硫丹 ) ,Endrinaldehyde(乙醛异狄氏剂 )以及EndosulfanII(硫丹 ) ,Dieldrin(狄氏剂 ) ,Deta HCH和Beta HCH 7种有机氯农药在 1 8种有机氯农药中都占主要部分 ;九龙江口的六六六的含量顺序 :β >δ α >γ ;对于滴滴涕 ,表层水中的含量 :DDE DDD >DDT ;间隙水中的含量 :DDE DDT >DDD ,二者DDE的含量都在总DDTs的 50 %以上 ,说明环境中的DDTs主要降解为DDE ;九龙江口有机氯农药随着盐度梯度 ,在河口中呈去除趋势 ;且间隙水中有机氯农药比表层水中的浓度高 ,说明其倾向于吸附在沉积物颗粒上 ,其浓度差使得有机污染物可能通过再悬浮等过程从底层向上层迁移 .九龙江口的有机氯农药污染与其他港湾相比 ,污染水平相当 ,部分站位水质有机氯农药 (HCHs和DDTs)超过国家一类水质的标准 .Organochlorine Pesticides at the water(surface water and porewater) in Jiulong River Estuary were determined. The range of organochlorine pesticides at surface water was 51.3~2479ng/L, and the concentration in porewater was 266~33355ng/L. The results showed that the organochlorine pesticides were removed in the estuary and the sediments were the reservior of the organochlorine pesticides. Compared with the results of other harbor and estuaries , it showed that the contamination for organic chlorine pollutants in Jiulong River Estuary was similar to those of others. At the same time,the risk of organochlorine pesticides in the estuary was evaluated.1998年教育部重点项目、基金委资助留学人员短期回国工作讲学专项基金!项目联合资助 (4 9910 76 0 74

    The trends and characteristics of organochlorines pollution in surface sediments of Xiamen Western Bay

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    利用GC ECD对厦门西港 1 998年 7月取得的 8个站位表层沉积物中的 1 8种有机氯农药 (HCHs,DDTs)等和 1 2种多氯联苯 (PCBs)进行分析 .其中有机氯农药的浓度范围ND(未检测出 )— 0 58ng/g(其中HCHs和DDTs的含量分别为ND—0 1 4ng/g与ND— 0 0 6ng/g) ,多氯联苯的浓度为ND— 0 32ng/g ,与 1 986、1 993年的厦门西港的分析结果相比较 ,污染程度明显降低 ;说明近年来的厦门的有机污染得到逐步控制 ,也与有机物随时间推移逐渐详解有关 ,分析表明多氯联苯和有机氯农药在厦门西港有着相似的分布特征 .The contents of 18 organochlorine pesticedes and 12 polychlorinated biphenyls(PCBs) in suface sediments from Xiamen Western Bay were analyzed by GC\|ECD. The range of organochlorine pesticides was ND—0 58?ng/g,and the PCBs were ND—0 32?ng/g.Compared with the results of Xiamen Harbor in 1986 and 1993, it showed that the pollution of organochlorines decreased gradually along the time, in Xiamen Harbor became and the contamination was more slightly than that of other Harbors or Estuaries. At the same time, it was found that the geological distributions of organochlorine pesticides and PCBs, also the HCHs and DDTs were similar to each other, which indicated that the polltion was cansed by a same source

    2019年秋季鲍鱼生产形势调研分析

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    福建、山东、辽宁、浙江、广东和海南是全国鲍主要养殖省。本文介绍了全国鲍主产区分布及总体情况,分析了秋季鲍生产形势及特点,指出了存在的问题,并给出了合理建议。为全面了解2019年全国鲍秋季养殖生产形势及发展趋势,9月下旬至10月中旬,鲍鱼调研组采取电话调查、问卷调查与现场调研的方式,对福建漳州、莆田、福州、宁德和平

    Study on organochlorine pesticide and PCBs at surface water in Xiamen Harbour

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    利用GC -ECD对厦门西港 1998年 7月取得的 9个站位表层水体中的 18种有机氯农药 (HCHs ,DDTs等 )和 12种多氯联苯 (PCBs)进行分析。其中有机氯农药的浓度范围 6 .6 0~ 32 .6ng/L(其中HCHs:3.5 1~ 2 7.8ng/L ,均值 8.5 7ng/L ;DDTs:0 .95~ 2 .2 5ng/L ,均值 1.45ng/L) ,多氯联苯的浓度为 0 .0 8~ 1.6 9ng/L ,同国内外其他港口海区相比较 ,其污染程度相对较低。同时 ,对有机氯污染的分析表明 ,发现近年来仍有有机氯的污染输入 ,其农药的使用主要集中在六六六和滴滴涕上 ;多氯联苯和有机氯农药在厦门西港有着相似的分布及来源特征。organochlorine pesticides and 12 polychlorinated biphenyls(PCBs) at the sruface water in Xiamen Harbour were determined. The range of organochlorine pesticides was 6.60~32.60 ng/L, and the PCBs concentrations were 0.08~1.69 ng/L. Compared with the results of other harbor and estuaries, it showed that the contamination for organic chlorine pollutants was more slight than those of others. At the same time, it was found that organochlorine pesticides and PCBs have the similar geological destribution and resources.福建省自然科学基金!项目 (D9810 0 0 3

    基于矩张量分析的特大山体破坏前兆孕震机制研究

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    工程岩体震源机制研究是岩体破坏灾害监测预警研究和应用的基础。针对一次特大爆破诱发的采空区上覆岩体产生特大破坏案例的前兆微震定位数据,采用矩张量理论对前兆微震源定位事件进行震源机制解反演,计算监测所得微震定位事件的矩张量并进行分解,获得纯双力偶成分MDC分量;采用Feigner和Young矩张量破裂判据计算得到破坏类型判别参数R值,对前兆微震事件的岩体破裂类型进行判断,同时根据矩张量分量计算震源体积不变部分参数T和体积变化部分参数k,据此绘制并研究了哈德森震源类型-T k图,分析表明前兆微震源的破裂类型主要为剪切破坏;进一步根据矩张量分解所得纯双力偶成分MDC分量,解得岩体震源处的断层参数。将震源机制解分析得到的前兆微震事件剪切破裂类型与现场山体宏观剪滑破坏相对比,其结果是基本一致的。研究表明基于微震矩张量理论对前兆震源机制解的分析,可较为准确地判断中尺度工程岩体破裂类型,该研究可作为进一步的中尺度工程岩体破裂机制研究以及岩体工程灾害预警研究参考。国家自然科学基金资助项目(51674218);;\n国家重点研发计划项目(2016YFC0600702
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