高压脉冲放电等离子体降解水中痕量硝基苯

采用高压脉冲等离子体技术处理水中痕量硝基苯,考察了脉冲电压峰值、电极间距、溶液初始pH值、氧气鼓入量和Fe2 添加量等因素对硝基苯去除率的影响.在脉冲电压峰值为35kV,电极间距为20mm,溶液初始pH值为10.2,氧气鼓入量为400ml·min-1,Fe2 添加量为30mg·l-1的实验条件下,水中硝基苯放电处理50min的去除率可达92.8%.     

高压脉冲放电处理焦化废水的研究

焦化废水中含有大量的氰化物,如直接排放将对环境产生很大的危害,本实验采用高压毫微秒脉冲产生的非平衡等离子体处理武钢焦化废水,分析了空气流量、SO2的质量浓度、放电时间等因素对实验的影响,放电之后发现当实验条件合适时,氰化物浓度可以降低90%以上,反应60min时则降低了93.93%以上。文章同时还探讨了放电等离子体去除氰化物反应机理。     

化感链霉菌6803菌株液体发酵工艺优化的研究

土壤微生物链霉菌6803菌株被证明对高等植物具有化感作用。采用单因子实验方法,研究液体发酵碳源、氮源、无机盐、发酵温度、发酵液初始pH值、摇床转速、发酵时间等对链霉菌6803菌株菌丝体产量及发酵液化感作用的影响,用均匀试验设计法优化了发酵工艺条件。结果表明：链霉菌6803菌株生长和产生化感作用的最佳发酵条件为：p（淀粉）=26．67g·L-1,p（蔗糖）=25．15g·L-1,p（NH4C1）=0．30g．L-1,黄豆饼粉浸液8．88％,所（NI-h）H2P04]=O．18g·L-1,p（FeS04．7H20）=O．002g·L-1,p（NaCl）=0．75g·L-1,pH值7．6,装量系数O．16,接种量3％,温度36℃,转速200r·min-1,发酵144h。本研究为利用微生物次生代谢产物作为天然除草剂奠定了基础。     

土壤中二价铁离子的伏安法测定

利用二价铁离子的联吡啶络合物,示差脉冲伏安法测定土壤中的二价铁离子．结果表明:二价铁离子的浓度与铁联吡啶络合物的峰电流在１．６×１０－６－９．８×１０－６ｍｏｌ·ｌ－１和９．８×１０－６－６．６× １０－５ｍｏｌ·ｌ－１浓度范围内成正比,检测下限为４．１× １０－７ｍｏｌ·ｌ－１,相对标准偏差为０．８４%(ｎ＝６)．在该方法中,联吡啶的浓度对二价铁离子联吡啶络合物的峰电位、峰电流及半峰宽度有影响,而测定体系的ｐＨ值和支持电解质的浓度对二价铁离子联吡啶络合物的峰电位、峰电流及半峰宽度影响较小．     

铝电极-低压脉冲电解含油废水影响因素

高压脉冲电源耗电量大,反应器绝缘安全要求高,不利于工业化应用.为了降低电耗、电极损失,采用铝电极-低压脉冲电解方法,对难降解的含油废水去油影响因素进行了单因子试验研究.结果表明:该方法对质量浓度为95.0 mg·L-1的含油废水中油的去除率超过65%.油去除率随电解时间、电压增加而增大,电解时间达到50 min、电压大于7 V以后受油分子扩散浓度影响而增加缓慢;适宜占空比、脉冲频率即可发挥脉冲作用,消除钝化效果,又可增强电解效果;体系pH值对电解影响较大,碱性条件有较好的电解效果;适量增加电解质用量可以提高油去除率;电极间距主要影响电耗,随间距减小耗电量增加.     

热脉冲（Heat pulse）法原理及其应用

简要回顾了各种树木水分利用测量方法，着得介绍了热脉冲法的原理和热脉冲仪的安装与操作，以及数据采集等。对各种方法的优缺点进行了评述。     

电化学法同时测定水样中的间硝基酚和对硝基酚

用微分脉冲伏安法同时测定了水样中含间硝基酚和对硝基酚的混合体系 ,在 0 1mol·l- 1 乙二胺 0 5mol·l- 1 氯化铵 (pH =8 5 0 )底液中于 - 0 5 0V和 - 0 69V (vsAg/AgCl)处出现两个灵敏度高且互不干扰的吸附波 .间硝基酚和对硝基酚分别在 4 0× 1 0 - 7— 8 0×1 0 - 5mol·l- 1 和 2 0× 1 0 - 7— 4 0× 1 0 - 5mol·l- 1 范围内与峰电流ip 呈良好的线性关系 .检测限分别为 8 0× 1 0 - 8mol·l- 1 和 6 0× 1 0 - 8mol·l- 1 .本法可用于环境废水中微量间硝基酚和对硝基酚的同时测定 .另外 ,对双组分体系的吸附性质和电极反应机理作了研究 .     

液相中MnO2催化臭氧化降解磺基水杨酸

研究了β-MnO2,γ-MnO2和MnSO4产生的胶状MnO2在液相中催化臭氧化降解磺基水杨酸的催化性能。结果表明，液相中MnO2催化臭氧化降解磺基水杨酸的活性与体系的pH值有关，而与其物相无关．在本实验条件下，三种MnO2在pH=1．0时均显示了较好的催化臭氧化活性，而在pH=6．8和8．0时却无活性。实验结果还表明，催化剂催化分解臭氧活性的高低与其催化臭氧化降解有机物的活性并无直接关系。     

瞬态吸收光谱技术研究4-氯酚水相降解的微观反应

利用瞬态吸收光谱技术进行了不同条件下４－氯酚水溶液的电子脉冲辐解,分别研究了体系中瞬时出现的·ＯＨ,Ｈ和水合电子等活性粒子与溶质的反应．对瞬态吸收光谱中的主要吸收峰做了归属,得到了ＯＨ－ａｄｄｕｃｔ,Ｈ－ａｄｄｕｔ和氯代酚氧基等一系列中间产物,并初步研究了这些瞬态物种的生长、衰减行为和可能的反应机理,得出了一些微观反应的速率常数．     

微分脉冲阴极溶出伏安法测定环境水样中的痕量硒

采用微分脉冲阴极溶出法测定环境水样中的痕量硒，以银电极为工作电极，在酸性介质0.06mol.l^-1HCl-0.07mol.l^-1HNO3溶液中于－0.35V(vs SCE)处富集20min，使Se(IV)电沉积为硒化银，然后，以40mV.s^-1的扫速，在碱性介质2．0mol.l^-1NaOH溶液中阴极溶出至－1.2V(vsSCE),硒化银被还原为银的溶出峰电位约为－0.85V(vs SCE),硒的分析校正曲直到40ng.ml^-1仍然成线性，检测下限为11.5pg.ml^-1,相关系为0.9982，灵敏度为10.93uA/ng.ml^-1,20ng.ml^-1的RSD（n=5)为1．26％，检出限（3σ为3.46pg.ml^-1,环境水样中常见离子的存在不干扰痕量硒的测定。     

Significance of spectral and temporal call parameters in the auditory communication of male grass frogs

Summary During the spawning period, male grass frogs (Rana temporaria L.) frequently produce short and long territorial calls in addition to mating calls. The calls differ in mean pulse number, duration, and pattern of amplitude modulation. Experiments in which recorded natural calls are played back reveal that male grass frogs are capable of discriminating the different conspecific calls. A male frog stimulated by mating calls always responds by producing mating calls in greater numbers (Fig. 3). Territorial calls presented at low intensity also cause an increase in the mating-call rate (Fig. 4), but at high intensity they clicit territorial calls and turning toward the loudspeaker. A combination of short and long territorial calls was especially effective in eliciting the phonotaxis response. As play-back experiments with simulated calls show, the carrier frequency and the pulse repetition rate are particularly important cues for recognition of conspecific calls (Fig. 5). A simulated call with a 400-Hz carrier frequency (the dominant frquency of the mating call) is just as effective as the natural call with the complete frequency spectrum (Fig. 3), whereas a 1100-Hz simulated call is ineffective (Fig. 5). The chief factors in discrimination among the conspecific calls are the call repetition rate and probably the amplitude and frequency modulation. Changes in the duration of the calls had little effect (Fig. 6). The available evidence suggests that the mating call has a reciprocally stimulating action on males in a chorus, whereas the territorial calls experess aggressiveness and give warning to other males.     

Female preferences for multiple attributes in the acoustic signals of the Italian treefrog, <Emphasis Type="Italic">Hyla intermedia</Emphasis>

The advertisement call of frogs and toads is an example of multiple message signal because different acoustic properties encode different kinds of biologically significant information. In the Italian treefrog, Hyla intermedia, pulse rate and frequency have been found to be under stabilizing female preferences and to encode information important for mate recognition, whereas the number of calls per call group have been found to be under directional preferences and, thus, to be important for mate quality assessment. In this study, we investigate preferences for calls that differ simultaneously in frequency, pulse rate, and number of calls per call group, and we ask how these properties interact with each other in influencing female mating decisions. Results of two-choice phonotaxis experiments provide no evidence to support the hypothesis that females process multi-attribute signals in a hierarchical way. In contrast, the pattern of preferences is consistent with the ‘preference function’ hypothesis, that is, with the hypothesis that females rank signals along an ordinal scale of values and choose accordingly. Pulse rate and frequency influence mating preferences more than does the number of calls per call group. The interaction between pulse rate and frequency is not additive but multiplicative: small differences in either pulse rate or frequency that, alone, have no effects on female choice, interact synergistically so that their combination has strong influence on female preferences. A preference repeatability test shows strong among-female differences in preference for multi-attribute signals. We suggest that this result reveals not only a variation in attribute values among females, but also a variation in the way females weight and combine attribute values into a single preference score.     

Microbial fuel cell with high content solid wastes as substrates: a review

With the increasing concern about the serious global energy crisis and high energy consumption during high content solid wastes (HCSWs) treatment, microbial fuel cell (MFC) has been recognized as a promising resource utilization approach for HCSW stabilization with simultaneous electrical energy recovery. In contrast to the conventional HCSW stabilization processes, MFC has its unique advantages such as direct bio-energy conversion in a single step and mild reaction conditions (viz., ambient temperature, normal pressure, and neutral pH). This review mainly introduces some important aspects of electricity generation from HCSWand its stabilization in MFC, focusing on: (1) MFCs with different fundamentals and configurations designed and constructed to produce electricity from HCSW; (2) performance of wastes degradation and electricity generation; (3) prospect and deficiency posed by MFCs with HCSWas substrates. To date, the major drawback of MFCs fueled by HCSW is the lower power output than those using simple substrates. HCSW hydrolysis and decomposition would be a major tool to improve the performance of MFCs. The optimization of parameters is needed to push the progress of MFCs with HCSW as fuel.

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A critical review on the recycling of copper and precious metals from waste printed circuit boards using hydrometallurgy

Currently, increasing amounts of end-of-life (EoL) electronic products are being generated due to their reduced life spans and the unavailability of suitable recycling technologies. In particular, waste printed circuit boards (PCBs) have become of global concern with regard to environmental issues because of their high metal and toxic material contents, which are pollutants. There are many environmental threats owed to the disposal of electronic waste; off-gasses, such as dioxins, furans, polybrominated organic pollutants, and polycyclic aromatic hydrocarbons, can be generated during thermal treatments, which can cause serious health problems if effective off-gas cleaning systems are not developed and improved. Moreover, heavy metals will dissolve, and release into the ground water from the landfill sites. Such waste PCBs contain precious metals which are of monetary value. Therefore, it is beneficial to recover the metal content and protect the environment from pollution. Hydrometallurgy is a successful technique used worldwide for the recovery of precious metals (especially gold and silver) from ores, concentrates, and waste materials. It is generally preferred over other methods because it can offer high recovery rates at a relatively low cost. This article reviews the recent trends and developments with regard to the recycling of precious metals from waste PCBs through hydrometallurgical techniques, such as leaching and recovery.

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Control system approaches to ecological systems analysis: Invariants and frequency response

The steady-state assumption is a mainstay for the analysis of ecological systems with more than three or four states. However, it is well accepted in ecology that inputs to large systems come in pulses assumed to have a reasonably constant magnitude and frequency. Steady pulse inputs and the use of electro-chemical–mechanical control systems methodology enables limited short term dynamic responses of ecological systems of a scale often occurring in systems of potential engineering importance to be analyzed. This paper explores and presents a survey of multi-input–multi-output (MIMO) control systems analysis of ecosystem network models to better understand pulse frequency issues and further develop experimentally verifiable approaches to testing the MIMO concept. The analysis process is demonstrated using two network model exemplars. Two aspects of MIMO analyses appear relevant to understanding ecological systems: (1) Eigenvalue invariant analyses and singular value decomposition (SVD) analyses enable assessment of stability and relative strength of states. Eigenvalues reflect time constants and provide a check on experimentally determined system matrices. (2) Analysis of SVD versus frequency for each output indicates maximum pulse frequencies that allow system components to benefit from pulsing. As a group, MIMO analyses complement other analytical methods and provide a theoretical systems focus convenient for analyzing ecosystems from an engineering perspective.     

黄原酯棉回收废弃电子电路板中金的研究

废弃电子电路板经王水溶解后，在盐酸介质中，用自制的黄原酯棉吸附。用6mol/L HCl洗涤杂质后，5％Na2SO3洗脱Au，控制溶液的流速为1mL/min。洗脱液浓缩后，再用20％ Na2SO3沉淀得到99.59%Au。     

An experimental examination of female preference patterns for components of the male advertisement call in the quacking frog,<Emphasis Type="Italic"> Crinia georgiana</Emphasis>

Even though females prefer particular components of a male display, their preferences may not be expressed during mate choice. Here, we quantified female preference patterns in the frog Crinia georgiana for call rate, pulse number and dominant frequency using two-speaker trials. Females typically chose signals emitted at a higher rate, with more pulses (when variation was extreme) and with an average dominant frequency. The results for pulse number and call rate agree with a previous field study which found that these two call components explained significant variation in male mating success. In contrast, the strong preferences for average dominant frequencies detected here disagree with the previous field study which failed to find any relationship between dominant frequency and male mating success. To explain the discrepancy we investigated whether the patterns of female preference for dominant frequency changed when another property, call rate, was varied simultaneously. Most females chose the call with an average dominant frequency when offered a choice between a call with an average dominant frequency and call rate or a non-average dominant frequency (±2 SD) and high call rate. When the differences in dominant frequency were reduced (±1 SD), females showed no clear preference for either signal. Accordingly, female preference patterns for one call component can vary with the expression of another. These results do not explain why dominant frequency did not account for any variation in male mating success under field conditions.Communicated by T. Beschlitz     

Male sperm whale (Physeter macrocephalus) acoustics in a high-latitude habitat: implications for echolocation and communication

Sperm whales (Physeter macrocephalus) are deep-diving predators foraging in meso- and bathypelagic ecosystems off the continental shelves. To investigate the ecophysiological and communicative function of various click types from male sperm whales in a high-latitude habitat, we deployed a large-aperture array of calibrated hydrophones off northern Norway (N69, E15). Data show that sperm whales in this habitat produce three click types: usual clicks, creak clicks and, occasionally, slow clicks. Usual clicks and creak clicks exhibit short duration, profound directionality and a frequency content suited for echolocation on meso- and bathypelagic fish and squids. The acoustic properties and low repetition rate of usual clicks are suited for long-range echolocation, whereas creak clicks have properties equivalent to signals in buzzes, the terminating pulse trains known from echolocating bats during prey capture. From these source parameters and the high acoustic activity during foraging dives, it is concluded that echolocation is an important sensory cue in prey location. Sound pressure levels of creak clicks and usual clicks measured off the acoustic axis suggest that sperm whales may be subjected to eavesdropping by conspecifics, thereby conveying information about food aggregations at estimated ranges of 6 km for creak clicks and 16 km for usual clicks. Slow clicks exhibit low directionality, low-frequency emphasis and a reduced repetition rate, suggesting that this click type is more suited for communication than for echolocation. Slow clicks can be detected by submerged conspecifics at ranges up to 60 km. Thus, sperm whales producing slow clicks may represent an odontocete species that utilizes long-range sound communication.     

兔子宫内膜蛋白等电聚焦电泳载体两性电解质pH范围及比例的选择

兔子宫内膜蛋白是研究早期胚胎发育过程中胚泡附植机制的关键因素之一．为了对子宫内膜蛋白进行有效的分离，本研究探讨了用于等电聚焦电泳的载体两性电解质pH范围及其比例．研究结果表明：在只有pH3～9．5的情况下，蛋白质谱带主要分布于胶条碱性端1／3区域，酸性端无谱带；在载体两性电解质pH3-9．5：pH4～6=1：4的情况下，蛋白质谱带主要分布于胶条碱性端2／3部分；在载体两性电解质以pH3-9．5：pH4～6：pH6—9=1：4：1时，蛋白质谱带分布比较均匀，酸性端也有谱带分布．这说明在作子宫内膜蛋白的等电聚焦电泳时采用pH3～9．5：pH4～6：pH6～9=1：4：1比较理想．     

A new source of dimethylsulfide (DMS) for the arctic atmosphere: ice diatoms

We report the first evidence that pennate diatoms growing within the bottom layer of first-year ice in the Arctic produce significant amounts of particulate dimethylsulfoniopropionate (DMSP_p) and dissolved DMSP+DMS. In 1992 in Resolute Passage, a tributary of Barrow Strait, DMSP_p concentrations within the bottom layer of ice reached 1055 mg S m^-3 at the end of the vernal bloom, a value one order of magnitude higher than the maximum value reported in antarctic ice. Bottom-ice concentrations in DMSP_p and DMSP_d+DMS were significantly correlated with the abundance of the dominant pennate diatom Nitzschia frigida. Intracellular concentration in DMSP of ice algae was very low (0.001 pg cell^-1) at the end of April when algae were light-limited and reached 1.17 pg cell^-1 in mid-May following an increase in light and algal growth. We calculate that the rapid release of the dissolved DMSP+DMS from the ice into surface waters following the ice break-up will generate a sea-to-air DMS flux of 0.7 mg S m^-2 d^-1, a pulse ten times higher than the mean arctic summer flux. We estimate that this 1-d pulse represents up to 5% of the annual DMS emission in the Arctic.