December 18, 2008:
The three-pulse z-filter 3QMAS pulse program with cogwheel phase cycling for I = 3/2 system is provided by Y. Millot.
July 18, 2008:
The replacement of EasyPHP1.8 by EasyPHP2.0b1 requires some modifications:
(1) Three lines were modified in the httpd.conf file of EasyPHP 2.0b1/conf_files folder:
Options Indexes FollowSymLinks Includes
AddType text/html .shtml
AddOutputFilter INCLUDES .shtml
(2) In PHP files of the web site, <? was replaced with <?php
June 30, 2008:
Mozilla Firefox 3 requires new font installation to view MathML formulae properly.
June 6, 2008:
Two approaches, coherence filtering and phase cycling, are applied for simulating the variation of echo or antiecho amplitudes versus a pulse duration in three-pulse phase-modulated split-t1 MQMAS sequences applied to spin I = 5/2 systems. These phase cyclings are tested with SIMPSON1.1.1 Tcl scripts.
An excellent agreement is obtained with these two approaches when more coherence transfer pathways are considered when the third pulse is selective. The coherence filtering approach provides the results in much shorter simulation time than the phase cycling approach.
March 26, 2008:
Two methods for inputting Chinese characters via a QWERTY keyboard, based on the structure of characters rather than their pronunciation, are described:
- Cangjie method developed in 1979 by Taiwan for inputting traditional Chinese characters;
- Wubizixing method developed in 1986 by People's Republic of China for inputting simplified Chinese characters.
Now with modern input method editors, both methods allow the inputting of traditional and simplified Chinese characters.
January 1, 2008:
The effect of the NMR probehead deadtime on the one-pulse MAS line intensity has been simulated with a SIMPSON1.1.1 Tcl script. Two scripting commands are available: the pulse command with zero RF amplitude and the delay command.
December 2, 2007:
Two approaches, coherence filtering and phase cycling, for simulating the variations of echo and/or antiecho amplitudes versus a pulse duration in three-pulse MQMAS sequences:
whose third pulses are a soft or weak amplitude pulse are tested with SIMPSON1.1.1 Tcl scripts.
An excellent agreement is obtained with these two approaches when more coherence transfer pathways are considered. The coherence filtering approach provides the results in much shorter simulation time than the phase cycling approach.
October 30, 2007:
The winding numbers for cogwheel phase cycling of three-pulse split-t1 3QMAS sequence applied to a spin I = 3/2 system have been determined using two web tools:
- XML (eXtensible Markup Language) for modelling the pulse sequence and the associated phase cycling;
- XSLT (eXtensible Stylesheet Language Transformation) for numerical search of these winding numbers.
These web pages require the installation of mathML plugin.
SIMPSON1.1.1 simulation of the antiecho amplitude using these winding numbers and that using coherence filtering method agree with an accuracy of 10-8.
September 4, 2007:
Procedure for allowing Internet Explorer 6+ to display scalable vector graphics (SVG) in web pages coded with SVG 1.1 markup language is described. However, vector graphics cannot be printed within IE.
Our first web page coded with SVG1.1 is that of the quadrupole interaction.
August 1, 2007:
Procedure for allowing web browsers (Mozilla/Firefox, Internet Explorer 6+, and Opera 9+) to display mathematical content in web pages coded with mathML 2.0 markup language is described.
July 1, 2007:
Phase cycling procedures for shifted-echo MQMAS sequences are analyzed with SIMPSON1.1.1 Tcl scripts using two approaches: (i) filtering the desired coherences associated with the coherence transfer pathway diagram, and (ii) explicit phase cycling the pulses and the receiver in a simulated experiment.
June 19, 2007:
Phase cycling procedures for two-pulse MQMAS sequences and z-filter MQMAS sequences are analyzed with SIMPSON1.1.1 Tcl scripts using two approaches: (i) filtering the desired coherences associated with the coherence transfer pathway diagram, and (ii) explicit phase cycling the pulses and the receiver in a simulated experiment.
For two-pulse 3Q-MAS experiments, these two approaches provide the same simulation data about echo and/or antiecho amplitudes.
For three-pulse z-filter 3Q-MAS sequences, these two approaches may not generate the same simulation data for echo and/or antiecho amplitude, depending on the experiment. A disagreement means that the phase cycling procedure does not properly describe the coherence transfer pathway diagram.
When a phase cycling approach generates the same echo and/or antiecho amplitudes as the filtering approach, the phase cycling procedure is valid whatever the nature (strong pulse or not) of the third pulse.
March 14, 2007:
A modification of the AU program xfshear is proposed for shearing 2-dimensional MQMAS spectrum acquired with the SPAM echo/antiecho pulse program.
February 8, 2007:
The definition of echo and antiecho in MQMAS experiments are provided.
The AU program xfshear for shearing MQMAS spectra has been commented.
February 6, 2007:
January 4, 2007:
December 8, 2006:
SPAM echo/antiecho pulse program from Bruker is described.
December 5, 2006:
Mathematica-5 notebooks and SIMPSON1.1.1 Tcl scripts are provided for the simulation of echo and antiecho amplitudes in MQMAS NMR: amplitude-modulated two-pulse and phase-modulated shifted echo sequences.
November 21, 2006:
Two types of pulse program for shifted echo sequences are provided: those with three strong pulses and those in which the last pulse is a selective pulse. The phase cycling for the third pulse and the receiver also differ in these pulse programs. Strong pulses allow a better excitation of off-resonance spins.
September 26, 2006:
In the topic about quadrupole interaction, Mathematica notebooks and SIMPSON Tcl scripts are provided that simulate the soft pulse added mixing (SPAM) and z-filtered MQMAS of 27Al.
June 16, 2006:
In the topic about quadrupole interaction, Mathematica notebooks and SIMPSON Tcl scripts are provided that simulate the central line intensity of 23Na for pulse duration t increasing from 0 to 20 Âµs by steps of 1 Âµs. 23Na is a spin I = 3/2 rotating at the magic angle, excited by an x-pulse and submitted to the first and second orders quadrupole interaction.
The discussion is centred on the effects of the sign of the asymmetry parameter on the line intensity. A method is proposed that allows both Mathematica notebook and SIMPSON Tcl script to provide the same results for powder samples, independent of the convention used to define the asymmetry parameter.
May 18, 2006:
The site applies CSS without table for its presentation. As a result, the pages appear differently in different Web browsers.
With Netscape 4.7, the site appears without style, in pure html presentation.
With Internet Explorer 5 for Mac, the submenu for downloading applet source code is not available. The following URLs should be used:
- http://www.pascal-man.com/JDK1.1.8-download/download-jdk.shtml for JDK1.1.8 applet source code;
February 22, 2006:
A new topic about quadrupole interaction is introduced. The first contributors are Y. Millot and R. Hajjar.
February 17, 2006:
SIMPSON Tcl scripts are available for simulating and fitting the central-line intensity of a spin I = 3/2 in single crystal excited by the composite-pulse sequence, the first-pulse length being variable and the other two constant.
Due to different conventions for the definition of the asymmetry parameter used in SIMPSON and the Java applets, these two approaches provide different simulations. Fortunately, as proposed by Klaus Eichele, if we add 90° to alpha, the first Euler angle in SIMPSON Tcl scripts, these two approaches give identical results.
January 30, 2006:
Carr-Purcell-Meiboom-Gill (CPMG) echo train pulse program for Avance AQX NMR spectrometers with HADC digitizer and analog filtering is provided by Y. Millot.
January 18, 2006:
Carr-Purcell-Meiboom-Gill (CPMG) echo train pulse programs for Avance AQX NMR spectrometers are provided by Y. Millot:
September 5, 2005:
The all-HTML4.0-based design of the site becomes a mixture of XHTML1.0 with tables and CSS design. As a result, the pages appear differently in different Web browsers.
Most files have .shtml extension instead of .html extension.
June 24, 2005:
NMR references about ST-MAS experiments are introduced.
June 19, 2005:
NMR references about double-resonance experiments such as INEPT, DEPT, REDOR, REAPDOR, SEDOR, TEDOR, and TRAPDOR are introduced.
January 3, 2005:
Two JDK1.3 Java applets are available for the optimization of the central-line intensity or the echo and the antiecho amplitudes provided by:
- a two-pulse sequence, where the first pulse excites the on-resonance Â±p-quantum coherences simultaneously, and
- the MQMAS sequence, where the first pulse excites only a single on-resonance p-quantum coherence.
The powder sample is in a rotor spinning at the magic angle. The rotor speed is a parameter of simulation. Only the first-order quadrupole interaction is taken into account during the pulses.
These JDK1.3 applets should run without trouble in Netscape 7.x under MS Windows or Unix operating systems. On the other hand, if Internet Explorer 5.x or 6 is used, we must install the Java plug-in for MS Windows.
Furthermore, these applets can be launched with Java Web Start from recent browsers and from Internet Explorer 5.x and 6 if Java plug-in is installed. A JDK1.3 applet becomes an application independent of the browser.
August 10, 2004:
The installation of Java plug-in for Internet Explorer 5.X and 6.0 in Windows operating system is described for running applets compiled with Sun's J2SE v1.2 SDK or higher. This installation is required for Windows XP which does not contain Microsoft Java Virtual Machine.
May 17, 2004:
Amplitude-modulated and phase-modulated shifted-echo pulse programs for Avance NMR spectrometers and 3Q-MAS experiments are provided by Redouane Hajjar.
May 1, 2004:
The various MQMAS sequences applied to half-integer quadrupole spins and the associated references are presented in Home and Applets > Pulse Sequence > MQMAS pages.
For each sequence, practical data are provided: pulse-sequence diagram, coherence-transfer pathways, detection mode in F1 dimension ...
The symbols (1), (2), (3), or (4) at the end of a reference title mean the pulse-sequence diagram, the coherence-transfer pathways, the phase-cyclings, or the receiver phase relationship are available in the reference.
March 1, 2004:
The procedure for shearing a 2D MQMAS spectrum of half-integer quadrupolar spin with the processing software RMN(fat) of P. J. Grandinetti is provided by Yannick Millot in the Pulse program page.
February 1, 2004:
The installation of Mozilla 1.6, Java 2 Runtime Environment, and Java plug-in for Red Hat Linux 8 is described in the FAQ page.
January 24, 2004:
The other NMR applets for a single crystal and for a powder written for SUN's JDK1.1.8 are available from the HOME page. The associated applet source codes are also available for downloading.
January 5, 2004:
Four applets (one-pulse and MQ-MAS for a single crystal and for a powder) written for SUN's JDK1.1.8 are included. From user point of view, the main improvement of these applets is the simultaneous displacement of the pulse length with the corresponding simulated line intensity using a single scrollbar.
Unfortunately, the number of pulse length is limited to about 100. Therefore, the line intensity simulation must be performed in several steps if the number of pulse length is greater than 100.
The applet source codes of the NMR one-pulse sequence applied to a single crystal, written for SUN's JDK 1.1.8, are available for downloading. The installation instructions are provided for WINDOWS-based computer users. They are similar to those written previously for SUN's JDK1.0.2. The applet source codes of the other NMR pulse sequences will be available for downloading soon.
The main changes in the new source codes concern with the event handling. Each event appears as an anonymous class inside OneXtalJDK118.java. As a result, more files are generated by the compiler. They have the following filenames: OneXtalJDK118$i.class, where i is an integer.
The JDK1.1.8 applet source codes describing the one-pulse sequence for a powder and the MQMAS sequences for a single crystal and for a powder are also provided.
April 28, 2003:
References about NMR books, encyclopedia, reviews, and theses are presented.
January 2, 2003:
An internal search engine for NMR references in the mySQL data base of this site is available. Search can be performed on a nucleus, author names, keywords in the title of an NMR reference, a journal, a year, or any combination of these criteria.
This internal search engine is accessible from the home page via the SEARCH NMR references in data base link or via the [Search references] link of the top menu bar in the other pages.
November 18, 2002:
Solid-state NMR references for aluminum-27, boron-11, cobalt-59, lithium-7, oxygen-17, rubidium-85/87, sodium-23, xenon-131, and vanadium-51 are organized as directories:
|Directory of solid-state Al-27 NMR references|
September 4, 2002:
The sign of the Larmor frequency in the Periodic Table and in each nucleus page has been changed. We follow the conventions well discussed by Malcolm H. Levitt, in "Spin dynamics, Basics of Nuclear Magnetic Resonance (Wiley, Chichester, 2001). That is
Larmor_frequency = -(gyromagnetic_ratio)*magnetic_field.
A nucleus with a positive gyromagnetic ratio has a negative Larmor frequency.
July 20, 2002:
Three more Java applets (rotary echo, spin lock, and two pulses) for a single crystal and for a powder are added.
July 19, 2002:
The page describing the different panels of an applet is divided into four pages: introduction, simulation, experimental, and fitting and printing pages.
The NMR reference page that supports the applets is divided into eight pages: one pulse, rotary echo, spin lock, composite pulse, two pulses, Hahn echo, MQ-MAS, and Solomon echo pages.
Similarly, the page providing the pulse programs for Bruker spectrometers is divided into several pages, each one describing a specific pulse program.