bluuebunny/crossref_metadata_2025 huggingface dataset:
Ichthammol and its pharmacopoeial use
Authors: Gugenheim P. G. , McLachlan T. , Jones J. M.
Published: July 2007

The British Pharmacopoeia requires ichthammol to be miscible with fixed oil, whereas the French Codex requires it to be immiscible. Investigation has shown that ichthammol containing about 50% water is emulsifiable with fixed oils only under certain conditions, and that the pharmacopoeial requirement needs amendment. The sulphur contents of ichthyol and ichthammol have been studied and it has been found that the sulphide‐ and thiophen‐sulphur are reduced by sulphonation. No connexion has so far been found between the sulphur distribution of samples of ichthammol and their bactericidal activity.
The effect of the depth of immersion on the chemical constitution of some of the sub‐littoral seaweeds common to Scotland
Authors: Black W. A. P.
Published: July 2007

An investigation into the variations in chemical constitution of the common British Laminariaceae, L. cloustoni, L. digitata and L. saccharina, collected at depths of 1–24 m., has been carried out in Orkney. At certain times of the year variations in chemical composition, in addition to those due to the recognized seasonal variations, have been found to occur in the fronds with very little variation., in the stipes. In general, in the fronds an increase in mannitol occurs with depth, reaching a maximum at 6–10 m., indicating that maximum photosynthesis probably occurs at that depth, in agreement with the observations of previous workers. Below 10 m., the mannitol decreases again. Laminarin decreases progressively with depth, being at a maximum at 3–6 m., and is absent in samples from 3 depth below 16 m.
Separation of the organic constituent of black liquor
Authors: Clare K. E. , Sherwood P. T.
Published: July 2007

A method of constructing road foundations, at present in the development stage, is to waterproof the soil by the aBdition of small quantities (I‐2″ of certain resins. Since these resins arc obtaincd chiefly from hard‐currency areas, work at the Road Research Laboratory has been directed towards finding substitute materials available in this country. In particular, attention has been directed to the orgnnic constituents of the alkaline black liquors obtained during paper pulp manufacture in this country.
Concrete road jointing materials
Authors: Millard R. S. , Critchell P. L.
Published: July 2007

In cxpansion joints two forms of jointing matcrial are required : (i) a pre‐formed joint filler which provides a spaccr between adjacent slabs to accommodatc expansion of the concrctc; (ii) a scaling compound, filling the top inch or so of the joint, which is intcndcd to prevent the entry of water and grit. In contraction joints, a scaling compound only is rcquircd. The desirable propcr‐ties of prc‐formed joint fillcrs and of joint‐scaling compounds are discussed. Thc main rcquiremcnt of joint fillcrs is that they shall bc compressible, and thcre appears to be no problem in providing satisfactory matcrials; soft wood, fibrc‐board, cork and cellular rubber have all been uscd succcssfully. No satisfactory scaling compound has yet been cvolvcd. The desirable propcrrics of scaling compounds have been dcfincd by laboratory tests in conjunction with road experiments and it is considcrcd that scaling compounds should be satisfactory from the following aspccts: (i) case of application; (ii) adhesion to concrctc; (iii) cxtcnsibility at low tcmpcraturcs on the road; (iv) resistance to flow at high temperatures on the road; (v) rcsistancc to the ingress of grit; (vi) weathering and ageing. Tests havc bcen dcvclopcd at the Road Rcscarch Laboratory to examine the more important of thcsc aspccts and standards for satisfactory road performance are rccommcndcd. Gcncral dcscriptions are given of the properties of the different types of scaling compound availablc. Thc most satisfactory compounds at prescnt availablc are rubbcr‐bitumens. Most scaling compounds are hot‐poured and it is considered that there can bc littlc furthcr improvement in the performance of materials which are poured in a hot fluid condition. The advantagcs and difficultics of cold‐applied scaling compounds are discusscd.
Destruction of cyanide in waste waters by chlorination
Authors: Eden G. E. , Hampson B. L. , Wheatland A. B.
Published: July 2007

A study of the reactions of sodium and calcium hypochlorites with buffered alkaline solutions of potassium cyanide indicated that the first product was always cyanogen chloride, which was rapidly hydrolysed at pH II or above without further absorption of available chlorine. At lower pH values additional chlorine was absorbed up to a total of 5·75 gram‐atoms per gram‐molecule of cyanide. At pH II the reaction of hypochlorites with the complex cyanides of zinc and cadmium was similar to that with potassium cyanide; cupro‐cyanide was also rapidly attacked, with oxidation of cuprous copper to the cupric state, but nickelocyanide was only slowly attacked.

A process was developed for treating electroplating wastes, or other waste waters containing cyanide, by reaction with calcium hypochlorite at pH II. The process would be applicable to liquids containing simple cyanides and the complex cyanides of zinc, cadmium, and copper, but not to solutions containing nickel.
Viscosity of mixed vapours
Authors: Silgardo R. B. , Storrow J. Anderson
Published: July 2007

Measurements have been made of the viscosities of mixtures of methanol‐water and ethanol‐water vapours using a rolling ball viscometer. Viscosities at the condensation temperatures of the mixtures of various compositions have been found by extrapolating the measured values for superheated vapours.
Superfine grinding of coke and other materials
Authors: Mott R. A.
Published: July 2007

The methods for superfine grinding are reviewed in the light of recent experience at the Midland Coke Research Station during the grinding of coke and other materials.

The wet and dry processes arc compared, and it is shown that with dry grinding the end of effective grinding is caused by caking of the material in the mill. Wet grinding, by avoiding ultimate caking, enables grinding to continue to n further stage.

The effect of size and type of ball is discussed, and the benefits obtained by adding different alkalis and other materials during wet grinding are described and compared.
Depleting endogenous neurotrophin‐3 enhances myelin formation in the Trembler‐J mouse, a model of a peripheral neuropathy
Authors: Liu Ning , Varma Sushama , Tsao David , Shooter Eric M. , Tolwani Ravi J.
Published: July 2007

The heterozygous Trembler‐J (TrJ/+) mouse, containing a point mutation in the peripheral myelin protein 22 (Pmp22) gene, is characterized by severe hypomyelination and is a representative model of Charcot‐Marie‐Tooth 1A (CMT1A) disease/Dejerine‐Sottas syndrome (DSS). Given that the neurotrophin‐3 (NT3)‐TrkC signaling pathway is inhibitory to myelination during development, we investigated the role of the NT3‐TrkC pathway in myelination and manipulated this pathway to improve myelin formation in the CMT1A/DSS mouse model. Injection of NT3 to the TrJ/+ mice decreased the myelin protein P0 level in the sciatic nerves. Suppressing the NT3‐TrkC pathway with TrkC‐Fc, an NT3 scavenger, enhanced myelination in vitro and in vivo in the TrJ/+ mouse. Furthermore, we found that full‐length TrkC was expressed in adult TrJ/+ mouse sciatic nerves but was not detected in the wild‐type adults, suggesting that the full‐length TrkC is a potential target of treatment to enhance myelination in the TrJ/+ mouse. © 2007 Wiley‐Liss, Inc.
Decreased hippocampal cholinergic neurostimulating peptide precursor protein associated with stress exposure in rat brain by proteomic analysis
Authors: Kim Hong Gi , Kim Kil Lyong
Published: July 2007

The stress response alters behavior, autonomic function, and secretion of multiple hormones, including corticotropin‐releasing factor, adrenocorticotropin hormone, and cortisol, through the hypothalamic‐pituitary‐adrenal axis. Constitutive stress responses lead to a number of psychiatric disorders, including depression, posttraumatic stress disorder, Alzheimer's disease (AD), and other anxiety disorders through increased stress hormones and other unknown factors. Here, we performed a proteomic analysis of rat brain exposed to restraint stress compared with a nonstress group by using 2D‐DIGE and MALDI‐TOF analysis. Several proteins were identified by peptide mass fingerprint (PMF), including down‐regulated hippocampal cholinergic neurostimulating peptide precursor protein (HCNP‐pp). The current study demonstrates that HCNP‐pp mRNA and protein expression are decreased in rat hippocampus after stress exposure. The level of HCNP‐pp in H19‐7, a rat hippocampal cell line, significantly decreases with dexamethasone treatment, a synthetic glucocorticoid. Thus, this finding suggests that HCNP‐pp expression may decrease in response to stress exposure. Decreased HCNP‐pp from stress exposure may result in lower levels of HCNP that might contribute to a loss of acetylcholine production. © 2007 Wiley‐Liss, Inc.
They don't want to be temporaries: similarities between temps and core workers
Authors: Chambel Maria José , Castanheira Filipa
Published: July 2007

This study investigated the impact of employment status (temporary/regular) on the employee–organization relationship in samples from two firms employing both temps (n = 234) and regular or core (n = 204) workers. Temps and regular workers held similar beliefs regarding the nature of their employment relationship. However, among those temps for whom temporary work was their preferred status, the employment relationship was less socioemotional and more economic than was the case for other workers. When these temps preferred regular employment, their relationships were high socioemotional and low economic, comparable with that of core workers. A employee–organization relationship high on socioemotional terms was positively related to satisfaction with the organization, an attitude which in turn mediated the relationship between employment relationship and employees' performance and civic virtue behaviors (behaviors as assessed by their supervisors). Copyright © 2007 John Wiley & Sons, Ltd.
Rapid densitometric method for simultaneous analysis of umbelliferone, psoralen, and eugenol in herbal raw materials using HPTLC
Authors: Dhalwal Kamlesh , Shinde Vaibhav M. , Mahadik Kakasaheb R. , Namdeo Ajay G.
Published: July 2007

The term ‘phenolics’ refers to a vast array of biologically active compounds ubiquitous in plants, many of which have been used in traditional medicine for thousands of years. Umbelliferone, psoralen, and eugenol are widely occurring phenolic compounds of plant origin, for which many biological activities against chronic diseases have been reported. A simple HPTLC method has been developed for the simultaneous quantification of umbelliferone, psoralen, and eugenol. These three compounds were quantified in the dried fruit pulp of Aegle marmelos and in the fruit of Trachyspermum ammi and Foeniculam vulgare. The technique enables rapid and sensitive simultaneous analysis in different samples. The method was validated for precision, repeatability, and accuracy in accordance with ICH guidelines. The accuracy of the method was checked by a recovery study conducted at three different levels and the average percentage recovery was found to be 98.88% for umbelliferone, 100.104% for psoralen, and 99.33% for eugenol. The proposed HPTLC method for the simultaneous quantification of umbelliferone, psoralen, and eugenol was found to be simple, precise, specific, sensitive, and accurate. It can be used for routine quality control of herbal raw materials as well as formulations containing any or all of these compounds.
Preparation and chromatographic properties of a multimodal chiral stationary phase based on phenyl‐carbamate‐propyl‐β‐CD for HPLC
Authors: Si Ahmed Kahina , Tazerouti Fairouz , Badjah‐Hadj‐Ahmed Ahmed Yacine , Meklati Brahim Youcef
Published: July 2007

A phenylcarbamate derivative of 2‐hydroxypropyl‐β‐CD bonded stationary phase was prepared by a previously described method. Its enantiomeric recognition abilities were evaluated as chiral stationary phase (CSP) in normal, polar organic and RP conditions by HPLC. The relevant structural features of the prepared stationary phase which make it an effective chiral selector are discussed. This material seems to have an excellent enantioselectivity for a variety of racemic analytes in the three modes. Hence it can be considered a highly effective multimodal column. Retention factor (k), selectivity (α) and resolution (Rs) were the chosen parameters to describe the column performance. Optimization of these separations was discussed in terms of mobile phase composition, flow rate and structural patterns of the injected analytes.
A strategy to develop fast RP‐HPLC methods using monolithic silica columns
Authors: El Deeb Sami , Preu Lutz , Wätzig Hermann
Published: July 2007

Since the appearance of monolithic silica, much work has been done describing the properties of monolithic silica columns. Meanwhile the transferability of analytical methods from conventional to monolithic silica columns has been intensively investigated [1–5]. RP HPLC method development strategies for conventional columns should be updated or scaled to meet the higher performing monolithic column technology. Because of the high permeability of monolithic silica columns it should be possible to decrease the time for method development by applying high isocratic flow rates. Here we suggest a clear strategy for method development using monolithic columns. The strategy will be applicable for various sample compositions, e. g., acidic, basic, or neutral. The applicability of monolithic columns for especially complex separations of basic mixtures without the need of using a highly basic mobile phase that harms the column will be pointed out in this work. This work will describe in detail the actual method development process. For better understanding of our strategy, the influence of flow rate, column length, mobile phase composition, pH, and temperature will be discussed. Details about the application of a flow program will be mentioned.
Isolation and purification of lignans from Magnolia biondii Pamp by isocratic reversed‐phase two‐dimensional liquid chromatography following microwave‐assisted extraction
Authors: Zhao Weiquan , Zhou Tingting , Fan Guorong , Chai Yifeng , Wu Yutian
Published: July 2007

The dried flower buds of Magnolia biondii Pamp are one of the most widely used medicinal plants officially listed in the Chinese Pharmacopoeia. A 2‐D column‐switching system without sample loop trapping, where two columns were switched directly via a six‐port two‐position switching valve, was successfully applied for the first time to the isolation and purification of five lignans including pinoresinol dimethyl ether, magnolin, epi‐magnolin A, fargesin, and demethoxyaschantin from M. biondii Pamp after microwave‐assisted extraction. The introduction of the six‐port switching valve instead of sample loop assured 100% recovery from the first dimension to the second, and the injection volumes of the second dimension could reach 12 mL. In this mode of operation, the solvent consumption of the 2‐D approach was less than 30% that of conventional gradient methods with even larger sample size. The simultaneous operations of the two dimensions allowed the cycle time to be less than 16 min, compared to 90 min in the gradient elution single‐dimension mode of operation. All of the five lignans were isolated at high purities of over 99% with approximately 95% recoveries.
A sensitive and selective RP‐HPLC method for simultaneous determination of picroside‐I and picroside‐II in rat plasma and its application in pharmacokinetics studies
Authors: Lv Jing , Pan Liyi , Ye Yunhua , Zhou Yawei
Published: July 2007

A sensitive and selective HPLC method with UV detection for the simultaneous determination of picroside‐I and picroside‐II (active components of total glycoside of Picrorhiza scrophulariiflora Pennell) was developed and validated in rat plasma. After simple deproteinization using acetonitrile, analysis was performed on an RP‐C18 column (250 mm×4.6 mm id, 5 μm) with a mobile phase consisting of acetonitrile and water at a flow rate of 1.0 mL/min used in a gradient elution program. The UV detection wavelength was set at 262 and 277 nm. Linear calibration curves were obtained in the concentration range of 0.10–50 μg/mL for picroside‐I and 0.25–200 μg/mL for picroside‐II. The lower limits of quantification were 0.1 and 0.25 μg/mL for picroside‐I and picroside‐II, respectively. The recoveries from spiked control samples were up to 80% for both picroside‐I and picroside‐II. Accuracy and precision of the validated method were both within the acceptable limits of <15% at three quality control concentrations. The analytes were stable after three freeze–thaw cycles. The method was successfully used to determine concentrations of picroside‐I and picroside‐II after intravenous administration of total glycoside of Picrorhiza scrophulariiflora Pennell to rats.
An NIC‐based negative resistance circuit for microwave active filters
Authors: Sussman‐Fort Stephen E.
Published: July 2007

This article presents a method for synthesizing a negative resistance in MMIC technology. The circuit employed is a classical negative impedance converter (NIC) that has been terminated in an RLC one‐port specially designed to compensate for the parasitics of the active and passive elements. The procedure, which effectively translates a nonideal NIC design task into a well‐defined one‐port synthesis problem, is demonstrated in computer simulation for a four‐transistor MMIC network which achieves a purely real input resistance of −100 Ω over 1.5–2.5 GHz. An important application for NIC‐based circuits of this type is in the design of microwave active filters. © 1994 John Wiley & Sons, Inc.
The method of angular lines to solve cylindrical electromagnetic boundary‐value problems
Authors: Ma Jian‐Guo , Wolff Ingo
Published: July 2007

A method for solving cylindrical electromagnetic boundary‐value problems is presented. The method is semidiscrete. The wave equation is written in cylindrical coordinates and a differential‐discretizing process is used in angular direction, and in the radial direction the analytic solutions are used. The new method is called the method of angular lines (MAL). To confirm the validity of MAL Dirichlet‐ and Neumann‐type boundary‐value problems of a two‐dimensional scalar wave equation are investigated. The results show good agreement with previously published results. Advantages and disadvantages of the method are discussed. © 1995 John Wiley & Sons, Inc.
Waveguide mode solution using a hybrid edge element approach
Authors: Wilkins Gregory M. , Swaminathan Madhavan , Lee Jin‐Fa
Published: July 2007

A hybrid edge element approach for the computation of waveguide modes is presented. The electric field is decomposed into its transverse and longitudinal components, which are modeled in terms of two‐dimensional edge elements and scalar nodal elements, respectively, thereby satisfying the Dirichlet boundary condition at the perfect electric conductor boundaries and dielectric interfaces. Failure to do so results in the generation of spurious modes. This approach allows for the modeling of a three‐dimensional field quantity over a two‐dimensional boundary, namely the waveguide cross section. Another approach, the method of moments, serves as an excellent means of verifying the results obtained through use of hybrid edge elements. A comparison of the results obtained from both techniques are presented, along with the associated field plots obtained from the hybrid edge element approach for several geometries.
New applications of harmonic balance analysis
Authors: Odyniec Michal , Overstreet William
Published: July 2007

This article shows how the theory of averaging extends applications of harmonic balance analysis. Two examples are given: (i) a new approach to high‐Q oscillators, which results in an analysis of slowly varying envelope of oscillations rather than the oscillations themselves; and (ii) a rigorous analysis of frequency lock and of stability of multiple solutions in synchronized oscillators. Both results can be directly applied to diode and transistor oscillators and can also serve as benchmarks in testing nonlinear simulators. © 1995 John Wiley & Sons, Inc.
A hybrid‐ring directional coupler with modified ring impedances and two compensation stubs
Authors: Rosloniec Stanislaw
Published: July 2007

New explicit formulas for calculating the scattering parameters of a modified hybrid‐ring directional coupler are presented. It is also shown how port junction discontinuities of real couplers of this type, employed as equiphase antenna dividers, can be effectively compensated by using a pair of short open‐circuited transmission line stubs. The efficacy of the proposed approach is illustrated both by theoretical and by experimental results. © 1995 John Wiley & Sons. Inc.
An NIC‐based negative capacitance circuit for microwave active filters (invited article)
Authors: Sussman‐Fort Stephen E. , Billonnet Laurent
Published: July 2007

This article presents a method for synthesizing a negative capacitance in MMIC technology, and extends our earlier work (S. E. Sussman‐Fort, Int. J. MIMICAE, Vol. 4, No. 2, April 1994, pp. 130‐139) involving the realization of MMIC negative resistance. As before, we employ a classical negative impedance converter (NIC) that has been terminated in an RLC one port specially designed to compensate for the parasitics of the active and passive elements. We argue that, in most cases, this one port will be physically realizable, and we provide numerical results for the synthesis which supports this idea. The procedure is demonstrated in computer simulation for a four‐transistor MMIC network which achieves a virtually pure capacitance of ‐5 pF over 1.5‐2.5 GHz. Such NIC‐based negative capacitance (and resistance) has potential application in the design of microwave gyrators and active filters. © 1995 John Wiley & Sons, Inc.
A note concerning the use of field solvers for the design of microstrip shunt capacitances in lowpass structures
Authors: Matthaei George L. , Forse Roger J.
Published: July 2007

A technique is described for rapid, accurate design of microstrip two‐ and three‐port shunt capacitors such as may occur in lowpass structures. The methods take advantage of simple static calculations used in conjunction with a full‐wave field solver to aid in accounting for parasitic effects in lowpass structure design. © 1995 John Wiley & Sons, Inc.
CAD model of effective dielectric constant of microstrip line on M‐cut sapphire substrate
Authors: Vendik Irina B. , Kalendarov Emil T.
Published: July 2007

Simple and correct formulas in regard to frequency dispersion are derived for the calculation of an isotropic effective dielectric constant for the microstrip line on m‐cut sapphire substrate. The formulas were verified by comparison to the results of full‐wave analysis based on the equivalent surface impedance approach. The temperature dependence of the dielectric permittivity of sapphire is taken into account.
Managing the Token Ring
Authors: Waters Curtis
Published: July 2007

General Technology's GT16N series Smart MAU (SMAU) is the heart of a network management system which offers administrators and managers the hardware necessary to take control of 4/16 Mbps token ring networks.
Using the U.S. Robotics' Total Control PC to Manage a Dial Modem Network
Authors: Balton Don C.
Published: July 2007

Total Control is US Robotics' complete modem management system whose elements are designed to work together to streamline the installation, management and operation of a modem network and to increase its reliability.
An Intelligent IN
Authors: Gauti D. , Pujolle G.
Published: July 2007

The Intelligent Network [IN] is a network concept to ease the introduction of new services based on more flexibility and new capabilities. This paper describes an evolution towards a more intelligent structure provided by Advanced Information Processing techniques with emphasis on a Distributed Artificial Intelligence concept.
Net Results: The NetView‐Based Problem Resolution and Productivity Tool for the VTAM Environment
Authors: De Lillo Stephen
Published: July 2007

This article introduces Net Results, a NetView‐based full‐screen command processor that facilitates SNA Network management.
FDDI: Understanding the Physical Aspects of the Fibre Distributed Data Interface
Authors: Jones Katherine
Published: July 2007

This is the second of three articles focusing on FDDI. The definition and the applicable standards were covered in the previous article; the hardware associated with FDDI will be discussed herein; and the network management of FDDI will be described in a following article.
Keeping personal communications personal
Authors: Held Gilbert
Published: July 2007

In this article, we will focus our attention on the development and utilization of several types of cipher systems, since the use of a code system is typically impractical for hiding the meaning of messages in a rapidly changing corporate environment.
MONA: A return to network management basics
Authors: Walden Timothy M.
Published: July 2007

The ACC Systems Manager of Network Activity (MONA) represents a return to simplicity in the management and control of IP‐based multivendor internetworks. What follows is a look at the inner workings of the product and philosophies that shaped it.
Generic information structure for sdh management
Authors: Gegenmantel Eike
Published: July 2007

Network Information Models make up the link between the technical realization of a network and its management. The structure and working principles of such an information model will be shown for telecommunications networks based on the technology of the Synchronous Digital Hierarchy (SDH)
Installing and Using Net Ware Accounting
Authors: Held Gilbert
Published: July 2007

In this article, Net Ware accounting is presented in the form of a tutorial to provide those readers who have not considered using this optional feature with detailed information concerning its installation and use.
A Mathematical Model for the Investigations of Access Demands on Information Networks with Applications
Authors: Bakry Saad Haj , Al‐Dhalaan Abdullah , Al‐Muammar Abdulaziz
Published: July 2007

Investigation of demands on information networks helps in the planning, design, and improvements of such networks. This article presents a mathematical model upon which such investigations can be based and describes how the model has been used for the investigation of a GULFNET (the research network of the Gulf Cooperation Council Countries) case study.
Managing Desktop Assets
Authors: Muller Nathan J.
Published: July 2007

Today, PCs have become part of the business culture. However, trying to manage this diverse and growing assemblage of hardware and software has become a costly problem for many organizations.
Disaster recovery long‐range planning: A mandatory evolution for protecting data
Authors: Becker Hal Byron
Published: July 2007

The simplicity of centralized disaster recovery planning is gone forever for many users. It has been replaced with an incredibly complex array of questions and issues that must be explored and resolved. Many factors contribute to this complexity and this article identifies and explores some of them.
How Safe is Your Data Center?
Authors: Nevola John E.
Published: July 2007

The data center should be separated from the rest of the business and should not house executives, end‐users or non‐essential operational personnel. This configuration isolates the data center from the rest of the enterprise and greatly simplifies the planning of end‐user recovery.
Internet Firewall Servers Address Burning Corporate Security Issues
Authors: Cline Gregory P.
Published: July 2007

This article is abstracted from a Business Research Group report as part of BRG's Network Integration and Management Research Program.
Managing the Enterprise Network with LightWatch/Open
Authors: Muller Nathan J.
Published: July 2007

There are hubs for workgroups, departments and the enterprise. There are about 140 hub vendors providing innovative network solutions spanning each of these domains. One of these vendors, ADC Fibermux, offers the Crossbow family of multi‐LAN intelligent hubs. These are managed with LightWatch/Open, one of the simplest and intuitive management systems currently marketed.
GULFNET: The academic network of the arab gulf countries
Authors: Al‐Sulaiym Hamad A. , Al‐Muammar Abdulaziz , Bakry Saad Haj
Published: July 2007

This article provides an overview of GULFNET and its information services, with emphasis on KACST (King Abdulaziz City for Science and Technology, Saudi Arabia) services.
What is an incentive system?
Authors: Kemmerer Frances N. , Thiagarajan Sivasailam
Published: July 2007

Performance Technologists have come a long way—from producing zebra‐striped books to implementing innovative interventions. It is about time we applied our technology to where the money is: compensation packages and incentive systems. This new series will feature articles on different aspects of developing, implementing, evaluating, and improving incentive systems.
Buried‐contact silicon solar cells
Authors: Wenham Stuart
Published: July 2007

Recent technological and commercial developments for the buried‐contact solar cell (BCSC) are reviwed. Four of the world's largest manufacturers have entered into manufacturing agreements, with a number of these taking advantage of the high‐efficiency capabilities of the large‐area BCSCs to produce cells for solar cars in the 1990 and 1993 World Solar Challenges and in the solar car race across the USA in 1993. Despite the efficiencies and commercial interest acheived by the conventional structure for the BCSC, a number of areas for improvement remain. In particular, the rear aluminium‐alloyed region limits the cell performance, and dislocation generation resulting from stresses at the silicon/silicon dioxide interface can also play a significant role in reducing efficiencies.

Through the use of a photolithographically defined rear metal contact, efficiencies in excess of 21% and open‐circuit voltages as high as 693 mV for the hybrid BCSC have been demonstrated. the effect of the heavily diffused region beneath the metal contacts in the grooves is studied and its implications for the new generation of BCSCs with grooves on front and rear surfaces are considered. the economic and technological merits of a range of groove formation approaches are discussed, with a low‐cost, high‐throughput ganged dicing wheel saw with 35 wheels showing most promise.
Heteroepitaxial Inp solar cells for space applications
Authors: Weinberg I. , Flood D. J.
Published: July 2007

This review summarizes the current status of research aimed at development of heteroepitaxial InP solar cells. Details are presented for single junction and multijunction cells. We conclude with recommendations for future research.
The first forty years: A brief history of the modern photovoltaic age
Authors: Loferski Joseph J.
Published: July 2007

This brief history of the modern photovoltaic (PV) age is divided into four major periods: the beginning in 1953‐1954; the next steps, 1954‐1956; the space PV period, 1956‐1970; and the terrestrial PV period, 1970 onwards. the author began his participation in photovoltaics in 1953 and has been a participant in, or a witness to, the events that he describes.
The effects of atmospheric parameters on the global solar irradiance and on the current of a silicon solar cell
Authors: Zanesco I. , Krenzinger A.
Published: July 2007

In this paper we present the influence of each atmospheric parameter on the global solar spectral irradiance and also show how the short‐circuit current of a conventional Si solar cell. These results and the presented method are useful for analysing the outdoor performance of Si photovoltaic (PV) devices. For this reason we present a set of equations that can help to correct the short‐circuit current of the cell, in relation to the US standard atmosphere, when outdoor measurements are made. the method used is to simulate the global spectral solar irradiance under cloudless skies, using a set of equations selected from the literature, and the spectral short‐circuit current density of the silicon cell. the influence of atmospheric parameters on the solar cell current is known using the ratio of solar cell current density to global solar irradiance. We conclude that the atmospheric parameters (air mass, precipitable water amount, Angström's turbidity coefficient and aerosol particle size distribution) produce significant variation on Si cell short‐circuit current. We suggest taking account of them when studying the performance of PV devices under outdoor conditions.
VHF plasma deposition for thin‐film solar cells
Authors: Heintze M. , Zedlitz R.
Published: July 2007

Fast deposition rates, typical for very high frequency (VHF) plasma deposition, up to now have mainly been attributed to a more efficient silane decomposition as the results of an enhanced density of high‐energy electrons in the plasma.

In this work a‐Si:H was prepared at excitation frequencies in a wide frequency range between 25 and 250 MHz and at otherwise constant conditions. In order to understand the processes leading to the observed increase in deposition rate with frequency, the plasma was investigated by optical emission spectroscopy and mass spectrometry. Plasma‐substrate interactions were studied by impedance analysis and ion flux measurements. the results show that the high deposition rates are mainly the result of an increased surface reactivity of film precursors resulting from the ions impinging on the growth surface. It is shown that variation of the excitation frequency allows a flexible control of ion flux and energies. Conditions were optimized for the preparation of a‐Ge:H films, which require a flux of high‐energy ions to the substrate. Material properties were obtained that were comparable to results from deposition on the cathode of a radio frequency (RF) discharge.
Applying photovoltaic power to a petrol service station
Authors: Chendo M. A. C.
Published: July 2007

This paper considers the use of photovoltaics to power rural petroleum service stations, or as a back‐up for urban service stations where power supply from the national grid is rather erratic in a developing country like Nigeria. Issues concerning system design, choice of components and the economic considerations of such a conceptualized system are also discussed. the payback period based on simple payback analysis is about 5 years. It is envisaged that the service station will also provide facilities such as cathodic protection for storage tanks, battery charging and distilled water production.
World solar challenge 1993: The trans‐australian solar car race
Authors: Green Martin A.
Published: July 2007

In November 1993, over 50 solar cars left Darwin for the tortuous 3000 kilometre journey south across Australia to Adelaide. the top cars set a pace difficult for conventional vehicles to maintain. the winner, the Honda Dream, averaged 85 kilometres per hour (53 mph), with all top five place getters shattering the previous race record set by the General Motors (GM) Sunraycer in 1987. the improved performance was due to better aerodynamics, motor and power train efficiency and improved output power from the photovoltaic arrays on these cars. This report describes the race with emphasis on the solar cell and module technology used by the leading cars.
Polycrystalline silicon thin‐film solar cells: The future for photovoltaics?
Authors: Shi Z. , Wenham S. R.
Published: July 2007

Based on performance, material availability, consumer acceptance, life expectancy, environmental considerations and the potential for low cost, thin‐film polycrystalline silicon solar cells are well placed to have a significant impact in the future. of key importance will be the achievement of performance targets, because module efficiencies of at least 15% are probably necessary in the long term for photovoltaics to have a significant impact in grid‐connected applications. Strategies for achieving these performance levels with mediocre material quality and only moderate surface passivation and light trapping are presented. the challenges associated with the supporting substrate choice and layer depostion techniques and structures are discussed and the psesent practices reviewed. Important considerations include device performance, cost, throughput, device area and simplicity of fabrication and operation. Promising efficiencies in the vicinity of 15% have already been demonstrated using a number of different crystalline silicon layer‐formation techniques. Novel device structures based on incorporation of narrow bandgap materials (Si/Ge alloys) or defect layers, quantum wells and the impurity photovoltaic effect are considered, with particular emphasis given to approaches that compensate for the current loss in thin‐film cells. It appears increasingly likely that polycrystalline silicon thin‐film solar cells will have an impact on the development of photovoltaics in the future and may in fact provide the means for the substantial cost reductions necessary for significant penetration into utility markets.
Polycrystalline silicon‐film™ solar cells: Present and future
Authors: Barnett Allen M. , Collins Sandra R. , Cotter Jeffrey E. , Ford David H. , Hall Robert B. , Rand James A.
Published: July 2007

Future crystalline silicon solar cells will have increased performance and reduced cost. Increased performance will come from thin silicon with light trapping, provided that it includes back‐surface passivation. Cost reduction will come from the growth of this thin silicon light‐trapping structure on a low‐cost substrate. the silicon will be polycrystalline. Solar cells formed with thin (< 50 μm) silicon active layers can produce higher conversion efficiencies at reduced material requirements than conventional ingot‐based silicon devices. This paper presents the essential features of high‐performance device design based on thin silicon layers, the design features of the Silicon‐Film−TM technology, the sequence of products that emerge from its development and recent results from the first commercial‐scale, large‐area (225 cm−2) Silicon‐Film−TM solar cell product.
New generation of high‐efficiency solar cells: Development, processing and marketing
Authors: Jordan D. , Nagle J. P.
Published: July 2007

In 1985, BP Solar Australia (BPSA) licensed and began commercialization of the high‐efficiency buried‐contact solar cell technology developed and patented by the University of New South Wales.−1 Small‐area cells of 18% efficiency were soon produced in BPSA's Brookvale laboratory, leading on to a 5‐year development period in Australia and the establishment of a pilot production facility within the BP Solar España facility in Madrid in 1989.

This paper looks at the current technical and commercial situation within BPSA for this novel technology, and how its future is viewed relative to other processing technologies.
Reduction of the apparent shunt resistance effect in silicon concentrator solar cells
Authors: Terrón M. J. , Ĺuque A.
Published: July 2007

Silicon solar cells of lowly doped base, under concentration, show a slope in the low voltage region. the slope varies with the irradiance and is similar in some aspects to that caused by a shunt resistance. This apparent shunt resistance reduces the fill factor and the efficiency. In consequence, such cells cannot operate effectively at concentrations above 20 suns.

Actually, this apparent shunt resistance is due to the transition from low to high injection in the cell base. This is confirmed by an accurate simulation using the PC1D code. A semi‐quantitative model of the mechanism is developed. It is shown that by thinning the cells the mechanism is strongly reduced. Thin cells are fabricated virtually free of low voltage slope at concentrations of 80 suns.

Also, the existing short‐circuit current sub‐linearity is avoided in the thinned cells.
Characteristics of a‐Si solar cells prepared by the super chamber at a high substrate temperature
Authors: Nishikuni Masato , Takahama Tsuyoshi , Okamoto Shingo , Ninomiya Kunimoto , Nishiwaki Hidenori , Tsuda Shinya , Takeoka Akio , Ohnishi Michotoshi , Nakano Shoichi , Kuwano Yukinori
Published: July 2007

A new approach to high‐performance a‐Si solar cells was studied. a‐Si films prepared at a high substrate temperature (> 250°C) have a higher absorption coefficient and a low SiH2 bond density. the effect of deposition temperature on the open‐circuit voltage (Voc) has been investigated systematically for glass/SnO2 Ipin/metal and glass/metal/nip/indium tin oxide (ITO) structure a‐Si solar cells. The Voc is found to depend strongly on the thermal history of the p/i interface. A short‐circuit current of 19.5 mA/cm−−2 was achieved for an a‐Si solar cell using an a‐Si i‐layer with a thickness of 4000 Å, which was prepared at a substrate temperature of 270°C.
Accelerated publication 23.5% efficient silicon solar cell
Authors: Zhao Jianhua , Wang Aihua , Green Martin A.
Published: July 2007

The passivated emitter and rear locally diffused cell structure has been redesigned and has yielded independently confirmed one‐sun eficiencies of up to 23.5%, the highest ever for a silicon cell. A dotted front emitter contact design, PBr3 liquid‐source phosphorus diffusions and 400‐μm thick 10‐cm diameter wafers have contributed to this improvement. Some of the new cells have demonstrated open‐circuit voltages of 709 mV with an ‘inverted’ pyramid surface structure, the highest ever for a 23%‐efficiency silicon cell. Further improvement is expected in the near future.
Value of grid‐support photovoltaics to electric distribution lines
Authors: Travers Dean L. , Shugar Daniel S.
Published: July 2007

This paper reports on the results of using photovoltaic (PV) generation to provide grid support to electric distribution and transmission lines. the analytical methods presented in this paper have been developed to incorporate existing feeder rating methodologies, PV output data and a new evaluation protocol that assesses the effective load‐carrying capability of targeted PV in a grid‐support application. Research results were validated using the Photovoltaic for Utility Scale Applications (PVUSA) 500‐kW Kerman project. Findings indicate that targeted PV generation can reduce summer peaking distribution‐feeder line temperatures, which enables engineers to increase the effective capacity of distribution feeders under standard planning conditions. Evaluating specific feeder conditions with measured PV system output under standard planning conditions indicates PV full load‐carrying capability for the test case area for a PV output of up to 2 MW. For the line under investigation, the maximum allowable load increase is not expected to exceed 40% of the line capacity. the evaluation methodology, while applied to a specific line on a specific feeder, was designed to apply to a diverse set of lines and feeders under varying conditions.
Characterization and modeling of Cu(In, Ga)(S, Se)2‐based photovoltaic devices: A laboratory and industrial perspective
Authors: Tuttle J. R. , Sites J. R. , Delahoy A. , Shafarman W. , Baso B. , Fonash S. , Gray J. , Menner R. , Phillips J. , Rockett A. , Scofield J. , Shapiro F. R. , Singh P. , Suntharalingam V. , Tarrant D. , Walter T. , Wiedeman S. , Peterson T. M.
Published: July 2007

This contribution is a summary of a workshop convened to discuss the characterization and modeling of thin‐film CuInSe2(CIS)‐based solar cells, 17‐19 October 1993, in Estes Park, Colorado. the participants of the workshop are the authors of this paper. the subject matter was examined along four lines: device modeling, characterization, processing, and manufacturing issues. Fundamental numerical modeling has successfully guided device design efforts, including the design of variable band‐gap absorbers. Quantitative analysis, however, has been compromised by incomplete data on fundamental material properties. Phenomenological modeling and device characterization have sucessfully contributed to the understanding of the device physics. Although classified as a heterojunction device, the forward‐current recombination of the ZnO/CdS/CIS occurs almost exclusively in the space‐charge with diode quality factors ranging from 1.2 to 1.7 for good devices. the next generation of device modeling must incorporate two‐ and three‐dimensional effects. Recent fabrication work has focused on improving the CIS absorber and adding Ga and S to the matrix to increase its band‐gap. A better understanding of the ternary's fundamental properties is required to support the modeling efforts. Control of Ga and S introduction and the resulting absorber band‐gap profiles will facilitate the realization of optimized device designs. Inadequate understanding of fundamental device operation and process control at the laboratory level are amplified in the manufacturing environment. Modeling and characterization can identifv areas where corrective actions will result in improved performance and yield at the module level.
Zone‐melting recrystallization of silicon thin films for solar cell application
Authors: Ishihara T. , Arimoto S. , Kumabe H. , Murotani T.
Published: July 2007

Zone‐melting recrystallization (ZMR) has been applied successfully to fabricate a thin‐film silicon solar cell with high conversion efficiency that also has the potential to lower the material cost. It is found that seeding from an Si substrate during ZMR is not necessary for high‐quality thin‐film Si with a low defect density and the dominant (100) crystallographic orientation. This feature is very important because one can separate the thin‐film Si from the substrate in order to obtain a flexible solar cell and the substrate can be recycled. Lowering the scanning speed of the upper movable carbon strip heater has proved to be most effective for high‐quality crystal. In order to realize thin‐film Si solar cells, a 60‐μm thick Si active layer is deposited by chemical vapour deposition on recrystallized Si film. Pyramidal shape formation at the surface for light confinement by using (100) orientation and low‐energy H+ ion irradiation for the passivation of crystal defects has been applied to the fabrication of thin‐film Si solar cells and we achieved high conversion efficiencies of more than 14% for a 10 × 10 cm2 cell and 16% for a 2 × 2 cm2 cell.
Plasma etching: Safety, health and environmental considerations
Authors: Fthenakis V. M. , Moskowitz P. D.
Published: July 2007

Plasma etching in the photovoltaic industries involves several inorganic and organic fluorides, chlorides and bromides, some of which are toxic, corrosive, or flammable. Nitrogen fluoride, a relatively new etching material, presents special concerns because it may form self‐ignitable mixtures with some flammable gases. In addition, non‐toxic compounds (e.g. Freon), can form toxic by‐products in a plasma environment. Another safety concern is failure of vacuum pumps caused by corrosive effluents, and occupational safety issues associated with cleaning traps and reactors. These issues are discussed in this paper and the applicable safety and environmental control options are outlined.