A WDM-PON with DPSK modulated downstream and OOK modulated upstream signals based on symmetric 10 Gbit/s wavelength reused bidirectional reflective SOA

We investigate a wavelength-division-multiplexing passive optical network(WDM-PON) with centralized lightwave and direct detection. The system is demonstrated for symmetric 10 Gbit/s differential phase-shift keying(DPSK) downstream signals and on-off keying(OOK) upstream signals,respectively. A wavelength reused scheme is employed to carry the upstream data by using a reflective semiconductor optical amplifier(RSOA) as an intensity modulator at the optical network unit(ONU). The constant-intensity property of the DPSK modulation format can keep high extinction ratio(ER) of downstream signal and reduce the crosstalk to the upstream signal. The bit error rate(BER) performance of our scheme shows that the proposed 10 Gbit/s symmetric WDM-PON can achieve error free transmission over 25-km-long fiber transmission with low power penalty.

The Conversion of Non-Dispersed Polymers into Low-Potassium Anti-Collapse Drilling Fluids

Different drillingfluid systems are designed according to mineral composition,lithology and wellbore stability of different strata.In the present study,the conversion of a non-dispersed polymer drillingfluid into a low potas-sium anti-collapsing drillingfluid is investigated.Since the two drillingfluids belong to completely different types,the key to this conversion is represented by new inhibitors,dispersants and water-loss agents by which a non-dispersed drillingfluid can be turned into a dispersed drillingfluid while ensuring wellbore stability and reason-able rheology(carrying sand—inhibiting cuttings dispersion).In particular,the(QYZ-1)inhibitors and(FSJSS-2)dispersants are used.The former can inhibit the hydration expansion capacity of clay,reduce the dynamic shear force and weaken the viscosity;the latter can improve the sealing effect and reduce thefiltrate loss.The results have shown that after adding a reasonable proportion of these substances(QYZ-1:FSJSS-2)to the non-dispersed polymer drillingfluid,while the apparent viscosity,plastic viscosity,structural viscosity andfluidity index under-went almost negligible changes,the dynamic plastic ratio increased,and thefiltration loss decreased significantly,thereby indicating good compatibility.According to the tests(conducted in the Leijia area),the density was 1.293 g/cm3,and after standing for 24 h,the SF(static settlement factor)was 0.51.Moreover,thefiltration loss was reduced to 4.0 mL,the rolling recovery rate reached 96.92%,with excellent plugging and anti-collapse performances.

Implications of de Facto Reuse on Future Regulatory Developments for Beaufort-Jasper Water & Sewer Authority in Okatie, South Carolina, USA

A significant portion of the national water supply can be attributed to de facto or unplanned potable reuse, though the extent of its contribution is difficult to estimate. Fortunately, the contribution of Water Resource Recovery Facility (WRRF) effluent to waters that supply drinking water treatment plants has been documented by some communities. In the United States (US), among the top 25 most impacted drinking water treatment plants by upstream WRRF, 16% of the influent flow to the drinking water treatment plant under average streamflow and up to 100% under low-flow conditions is WRRF effluent. Currently, the full extent of de facto reuse in the US may be much higher because of population growth. The scenario is no different for Beaufort-Jasper Water and Sewer Authority (BJWSA) in South Carolina, US, with contributions to the Savannah River originating from numerous WRRF and other upstream dischargers. South Carolina coastal utilities such as BJSWA are considering direct and indirect potable reuse options, driven by disposal limitations and challenges. Currently, South Carolina does not have a framework, guidelines, or regulations for reuse, but discussions have started among the regulated community. In addition to understanding the extent of de facto reuse, the state will need to develop standards and best practices to enable future adoption of planned potable reuse solutions to water resources challenges. Such guidance should address human health risk management and technical considerations regarding treatment in addition to other factors, including source control, storage, fail-safe operation, monitoring, non-cost factors, and public acceptance. This study conducted a mapping assessment specific to BJWSA, sampled at four locations on Savannah River, and observed that de facto reuse is approximately 4.6% to 5.9% during low-flow months and is within the range generally observed nationwide. When coupled with evidence that planned potable reuse can improve human health and environmental risks, this practice is a meaningful option in the water supply portfolio for many utilities.

Performance of a Horizontal Flow Constructed Reed Bed Filter for Municipal Wastewater Treatment: The Case Study of the Prototype Installed at Gaston Berger University, Saint-Louis, Senegal

In Saint-Louis, Senegal, a constructed wetland with horizontal flow reed beds (FHa and FHb) has demonstrated significant efficacy in treating municipal wastewater. Analyzing various treatment stages, the system showed only a slight temperature variation, from an influent average of 26.3°C to an effluent of 24.7°C. Electrical conductivity decreased from 1331 mS/cm to 974.5 mS/cm post-primary treatment, with suspended solids (SS) dramatically reduced from 718.9 mg/L to 5.7 mg/L in the final effluent. Biochemical oxygen demand (BOD5) and chemical oxygen demand (COD) saw a notable decrease, from initial levels of 655.6 mg/L and 1240 mg/L to 2.3 mg/L and 71.3 mg/L, respectively. Nitrogenous compounds (N-TN) and phosphates () also decreased significantly, indicating the system’s nutrient removal capacity. Microbiological analysis revealed a reduction in fecal coliforms from 7.5 Ulog/100ml to 1.8 Ulog/100ml and a complete elimination of helminth eggs. The presence of Phragmites and Typha was instrumental in enhancing these reductions. The system’s compliance with the Senegalese standards for disposal into natural environments, WHO recommendations for unrestricted water reuse in irrigation, and the European legislation for water reuse was established. The effluent quality met the stringent criteria for various classes of agricultural reuse, illustrating the system’s potential for sustainable water management. This wetland model presents a robust solution for water-stressed regions, ensuring environmental protection while supporting agricultural needs. The study calls for ongoing research to further refine the system for optimal, reliable wastewater treatment and water resource sustainability.

Towards a business model for second-life batteries: Barriers,opportunities, uncertainties, and technologies

Electric vehicles(EVs) and the recent pandemic outbreak give cities a new trend to primarily private and shared mobility with low noise and less air pollution.Crucial factors for the widespread of EVs are the electrical charging infrastructure,driving range,and the reduction of the cost of battery packets.For this reason,there is a massive effort from manufacturers,governments,and the scientific community to reduce battery costs and boost sustainable electrical production and distribution.Battery reuse is an alternative to reduce batteries’ costs and environmental impacts.Second-life batteries can be used in a wide variety of secondary applications.Second-life batteries can be connected with off-grid or on-grid photovoltaic and wind systems,vehicle charging stations,forklifts,and frequency control.The present work aims to analyze the main challenges imposed on the reuse of batteries,the leading technologies for their reuse,and the different types of batteries in terms of their feasibility for second-life use.The main novelty of this work is the discussion about the barriers,opportunities,uncertainties,and technologies for the second life market.Here we summarize the present state of the art in reusing lithium-ion batteries discussing technical and economic feasibility,environmental impacts,and perspectives.The results show five business models that have been proposed in the literature,three types of markets for trading second-life batteries,and the main opportunities and barriers for each actor in the battery supply chain.

水声FBMC-OQAM通信的时变信道估计与符号检测

Filter bank multicarrier(FBMC)systems with offset quadrature amplitude modulation(OQAM)need long data blocks to achieve high spectral efficiency.However,the transmission of long data blocks in underwater acoustic(UWA)communication systems often encounters the challenge of time-varying channels.This paper proposes a time-varying channel tracking method for short-range high-rate UWA FBMC-OQAM communication applications.First,a known preamble is used to initialize the channel estimation at the initial time of the signal block.Next,the estimated channel is applied to detect data symbols at several symbol periods.The detected data symbols are then reused as new pilots to estimate the next time channel.In the above steps,the unified transmission matrix model is extended to describe the time-varying channel input-output model in this paper and is used for symbol detection.Simulation results show that the channel tracking error can be reduced to less than−20 dB when the channel temporal coherence coefficient exceeds 0.75 within one block period of FBMC-OQAM signals.Compared with conventional known-pilot-based methods,the proposed method needs lower system overhead while exhibiting similar time-varying channel tracking performance.The sea trial results further proved the practicability of the proposed method.

Optimization of Cognitive Femtocell Network via Oppositional Beetle Swarm Optimization Algorithm

In past decades,cellular networks have raised the usage of spectrum resources due to the victory of mobile broadband services.Mobile devices create massive data than ever before,facing the way cellular networks are installed pre-sently for satisfying the increased traffic requirements.The development of a new exclusive spectrum offered to meet up the traffic requirements is challenging as spectrum resources are limited,hence costly.Cognitive radio technology is pre-sented to increase the pool of existing spectrum resources for mobile users via Femtocells,placed on the top of the available macrocell network for sharing the same spectrum.Nevertheless,the concurrent reuse of spectrum resources from Femto networks poses destructive interference on macro networks.To resolve this issue,this paper introduces an optimal channel allocation model using the Oppo-sitional Beetle Swarm Optimization Algorithm(OBSOA)to allocate the channel with interference avoidance.A new OBSOA is derived in this paper by the inclu-sion of opposition-based learning(OBL)in BSOA.This algorithm allocates the channels used by PUs(PUs)to the secondary users(SUs)in such a way that inter-ference is minimized.This proposed approach is implemented in the MATrix LABoratory(MATLAB)platform.The performance of this proposed approach is evaluated in terms of several measures and the experimental outcome verified the superior nature of the OBSOA-based channel allocation model.OBSOA mod-el has resulted in a maximum signal-to-interference-plus-noise ratio value of 86.42 dB.

Lithium Ion Extraction from the High Ration Mg/Li Salt Lake Brine with Ionic Liquid in Triisobutyl Phosphate and Kerosene

1 Introduction As the lightest metal with the unique properties of energy production and storage,lithium is regarded as the new century energy metal.Lithium and its compounds were widely used in various industrial fields,especially

六边体系,广州,中国

作为对中国近年来伴随着建造热潮而出现的大量临时建筑的回应,这个可重复使用的建筑体系延长了建筑的生命周期,实现了真正意义上的可持续性。通过六边形模块的不同组合方式,它又可以灵活适用于不同的场地和功能。

SELECTED ABSTRACTS OF ARTICLES ON RARE METALS FROM CHINESE PERIODICALS

891—11 Polymerization of Conjugated Dienes withMixed Catalyst of Rare Earth and Other Transition MetalsⅠ.Butadiene Polymerization in the Presence of（NdCl3+FeCl3）.nphen-AIH（i-Bu）2 Catalytic systemThe mixed catalyst（NdCl3+FeCl3）.nphen with differentFe/Nd ratios was prepared by means of co-precipitation,and the polymerization of butadiene with the catalyst systemcomposed of（NdCl3+FeCl3）.nphen and AIH（i-Bu）2

PERFLUOROOCTANESULFONIC ACID CATALYZED FRIEDEL-CRAFTS ALKYLATION WITH OLEFINS IN GAS-LIQUID PHASE

Solid superacid perfluorooctanesulfonic acid(POSA)catalyzed Friedel-Craftsalkylation of aromatic hydrocarbons with olefins in gas-liquid phase.The alkylationsgave good yields with simple operation and easy work up.The amount of the catalystused in the reactions was small and could be reused.The optimum temperature of thereactions and the effect of the amount of the catalyst used in the reactions are alsodiscussed.

PREPAKATION OF THERMALLY REVERSIBLE HYDROGELS AND THEIR USE FOR THE IMMOBILIZATION OF CHYMOTRYPSIN

A series of hydrogels with lower critical solution temperature (LCST) were prepared and used for the immobilization of chymotrypsin. The activities of the immobilized enzyme decrease when the temperatures are raised above their LCST and recover below their LCST. This property is reversible.

OXIDATION OF ALKYLBENZENE CATALYZED BY RUTHENIUM—POLYMERBOUND 2,2'—BIPYRIDINE COMPLEXES

Oxidation of ethylbenzene, n-propylbcnzene and n-butylbenzene gives the corresponding ketones and alcohols in good yields by organic polymer supported low—valent Ru (Ⅱ) complexes under 1 atm. of air or oxygen at 100℃ in the absence of solvent. The calalytic selectivity to total ketone and alcohol ranged from 98.7％ to 100％. The polymer complex polymer—bipy—Ru—bipy (bipy=2, 2’—bipyridine) is very stable and can be reused for 5 times (each for 5h) without appreciable change in catalytic activity.

HYDROXYLATION OF n-HEXANE CATALYZED BY SUPPORTED Mn (Ⅲ)—PORPHYRIN COMPLEXES

Water-soluble Mn (Ⅲ)-porphyrins supported on various carriers as monooxygenase—like catalysts were used for n—Hexane hydroxylation by PhIO. The hydroxylation yields and XPS measurement of the catalysts indicate that the carriers containing—OH groups have favorable steric and electronic effect on Mn—porphyrins. Some influencing factors and the role of carriers are discussed.

高中英语阅读教学REUSE模式的构建与应用——以Unit 3 The million pound bank note为例

分析目前高中英语阅读教学存在功利化、模式僵化、碎片化、浅层化、资源利用不充分等典型问题。针对这些问题,构建REUSE模式,即Reviewing(复习)—Exploring(探索)—Unlocking(揭秘)—Sharing(分享)—Evaluating(评价)。以人教版高中《英语》必修3 Unit 3 The million pound bank note为例,探究在高中英语阅读教学中运用REUSE模式的教学流程及应用注意事项。

HYDROGENATION OF GLEFINS CATALYZED BY POLYMER-BOUND METALLOPORPHYRIN

the catalytic activity of the polymer-bound palladium tetrakis （p-hydroxylphenyl） porphyrin complex （P-THPP-Pd） has been studied. It is found that the polymer catalyst has high selectivity in hydrogenation of olefins, and the rate of initial hydrogen uptake for methyl acrylate is 29.0 （ml H2/min·g cat）.

SYNTHETIC AND CATALYTIC PROPERTY STUDIES ON SILICA SUPPORTED BIS-(ACETYLACETONATO) COBALT(Ⅱ) COMPLEXES^(**)

This paper reports mainly the preparation of silica supported acetylacetone ligands and their cobalt complexes, the characterization of their chemical structure, and the evaluation of their catalytic activity in the reaction for the preparation of ethers directly from alkanols and benzyl chloride. The results indicate that those silica supported β-diketone cobalt complexes (SACO) not only can simplify the reaction procedure of the ether preparation but also show a much higher catalytic activity in comparison with other homogeneous catalysts. In addition, SACO can be recovered and reused although their catalytic activity descend gradually as a result of the decrease in their cobalt content.

基于UNIX系统银行业务前台应用的软件复用技术

讨论了软件复用技术与银行前台业务系统开发的结合及其实现方案。并且对具体的图形界面、终端设备和打印报表的软件复用技术做了一些研究。

Reuse of Ferric Sludge by Ferrous Sulfide in the Fenton Process for Nonylphenol Ethoxylates Wastewater Treatment

In this paper, Fenton process was determined to be an effective technique to treat the refractory Nonylphenol ethoxylates (NPEOs) wastewater. The COD removal efficien-cies above 89% were obtained when the initial COD concentration was 12000mg/L. However, A large number of ferric sludge (SS=8.724g/L) would be produced after the Fenton oxidation of the wastewater and must be disposed appropriately. A novel process for Fenton sludge reused by low-cost ferrous sulfide (FeS) was also investi-gated. Experimental results show that the Fenton sludge could be reduced to produce a certain amount of Fe2+ in the acidic mixed liquor by ferrous sulfide. This mixed liquor from Fenton sludge could be used as the new catalyst in the Fenton process and was also highly effective for the NPEOs wastewater treatment. The residual ferrous sulfide from the mixed liquor could be used for the next batch of the