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  • Salamat Burzhuev added an answer in E-Beam Lithography:
    Issues with CVD graphene contact fabrication?


    Recently, I started to make contacts on top of CVD grown graphene, which we purchase from graphene supermarket. I use E-beam lithography and PMMA as a resist to make pattern on top graphene. After development of PMMA , I deposited 50 nm Cr by e-beam evaporation. Than, I left overnight my sample for lift-off in aceton. When I observed contact on top of graphene were damaged (peeled off from random places. I guess it might be due to PMMA residue on CVD graphene.

    I will be happy for any suggestions to solve this issue. Optical microscope image after lift-off is attached. 

    Thank you

    Salamat Burzhuev · University of Waterloo

    Thank you for suggestion! I use 1A/s rate and coat  50nm Cr. Do you think that deposition rate was problem? Or both deposition rate and thickness?

  • mi Xue added an answer in Mathematics Education:
    What is the difference between psychology of mathematics learning and psychology of mathematics education?

    I am writing a review about psychology of mathematics learning. But I found that there is only a international conference in this field called PME. PME is the short of International Group for Psychology of Mathematics Education. So can all these papers published in PME be regarded as research resources in psychology of mathematics learning? What is the difference between psychology of mathematics learning and psychology of mathematics education?

    mi Xue · Northeast Normal University

    Thanks for all of you giving anwsers to my question.I am a lucky dog.I will try to find journals such as Mathematics learning journal, Mathematical Cognition, Journal of Mathematical Psychology, Mathematics education research journal, Learning and Instruction, Journal of Mathematical Psychology.Focus on papers pubilished on European Conference of Mathematics Educationand the development of Central Conceptual Structures theory. 

    The task of psychology of mathematics learning is to find the regularity of mathematics learning and make students mastering learning regularity and methods.Psychology of mathematics learning is mostly related to the "learning" act and containts whole factors which affect mathematics learning such as attitudes, beliefs, teachers, friends etc.

    In my opinion,all these factors should be regarded as a system,which contains learning regularity such as learning hierarchy and  strategy group.When the system is fine enough, such as system of top students, there must be a way to success underlying this system.Anyway, we should discuss the inner causes of the excellent math ability of gifted students,the development of mathematical thinking process and the relationship between metacognition  in a framework such as cognitive load theory .

  • Abbas Rahdar added an answer in Magnetics:
    Can anyone tell me reasons for the magnetic single-domain formation?

    Can anyone tell me reasons for the magnetic single-domain formation?

    Abbas Rahdar · Zabol University

    Dear Ramanathan ,

    1-Explain why ferromagnetism is observed in the second half of the 3dtransition series and not in the first half?

    2-Why is considerable thermal fluctuations in superparamagnet?

    3-please tell me about behavior of Hard Axis Loops and easy Axis loops in thin films? 

    4-What is the origin of magnetism? for example , Why the secret of the origin of magnetism in iron is shell 3d while in the rare-earth metals 4f shell  is origin of magnetism? 

    5-In a monolayer (ultra thin film ) at absolute zero interaction between atoms can be high or low? Magnetization how?

    6-Easy and hard axes in a mono layer in the direction of that? 

    7-In a thin film the surface anisotropy overcome  on the shape anisotropy in what circumstances? 

    8-In a nanowire the helical anisotropy overcome  on the magneto crystalline anisotropy in what circumstances? 

    9-What are the conditions on the magnitude of Ms and out-of-plane crystal anisotropy for a thin film to have no in-plane magnetization? 

    10-please tell me why the remanence after magnetization in the hard direction is nonzero for Fe and Ni crystals but is zero for CO? 

    All the best,


  • Mgh Zaidi added an answer in Forsterite:
    What are the effects of nano-SiO2 and zircon on the physico-mechanical properties of in situ formed forsterite?

    the physico-mechanical properties of in situ formed forsterite

    Mgh Zaidi · G. B. Pant University of Agriculture and Technology, Pantnagar

    this may supposed to enhance the mechanical properties, electrical conductivity of foresterite.

  • Is flexural strength or tensile strength testing better:for polymers?

    I want to find mechanical properties of a polymer which is plastic-type. Which test will be better between flexural strength test or tensile strength test?

    Niranjan K. Naik · Indian Institute of Technology Bombay

    Both tensile and flexural tests are necessary. Based on the application, appropriate properties should be used.

  • What are the causes of false positive and false negative of amphetamine in urine by semi quantitative immunoassay?

    What are the causes of false positive and false negative of amphetamine in urine by semi quantitative immunoassay? I am using Roche analyzer for presumptive screening,  what are the chances of false negative samples?

    Rafiu Olagboyega Ariganjoye · Dr Sulaiman Al Habib Medical Group (HMG)

    False positive for amphetamine may be caused by many factors including structurally related like ephedrine and unrelated compound such as ranitidine and also cross reactivity of certain compunds during immunoassays are also known culprits. Chromatography analysis will assist in ruling out suspected false positive in these immunoassays. For false negative, look out for submission of adulterated or altered specimen ( very popular among "smart" patients in the state, but are easily detected)  and sometimes inappropriate cut off (sensitivity) of the anaylzer. Read the manufacturer instruction carefully

  • What substances interfere with phenolic compounds during determination of total phenolic compounds by folin-ciocalteu method and how to remove them?

    What comon methods or procedures to remove or reduce these substances from the phenolic compounds extract

    I. M. Abu-Reidah · Biodiversity and Environmental Research Center

    Sugars also may react with the reagent causing error quantifications

  • Hein Van Gils added an answer in Trade:
    What are some of the economic advantages and disadvantages of landlockedness (with reference to trade and growth)?

    It is generally perceived that due to lack of direct access to the sea, landlocked countries are primarily marginalized from major trade related networks and hardly benefit from trade opportunities due to their extreme reliance on their transit neighbors who may either have a weak or well-developed infrastructure (which have either detrimental or beneficial implications for trade and growth). Besides this usual perception most trade experts hold, what other advantages and possibly disadvantages are there for landlockedness?

    Hein Van Gils · Min of Environment & Tourism, Namibia

    Also in Asia, land-locked seems not universally negative for GDP/person; Nepal scores much higher than its neighbours, Mongolia is another case. Both are also relatively small and mountainous in their immediate environment. Maybe these two don't need sea or navigable rivers for trade with huge markets next door. And small may be beautiful in Asia as well, even among seaboard states: Singapore, Brunei, Timor-Leste, Hong Kong, all seaboard states.

  • Zhihong Feng added an answer in Graphene:
    How to passivate the graphene surface?

    How to passivate the graphene surface?So the graphene device can preserve relatively high mobility and no characteristic degradation for a long time in ambient environment!

    While you answer this question,please please give the detailed reference!Thank you very much!

    Zhihong Feng · Tianjin University

    How about depositing a metal layer to act as a passivation layer and removing it before your test?  Devices should be protected by N2. Good luck to you.

  • Brigette Metzler added an answer in Gender:
    Is it tenable to include the protection of rights of the boy child in gender advocacy programmes since 'gender' is not synonymous with feminism?

    Gender studies and advocacy have been understood to proceed from the premise that women and girls are victimized by various forms of discrimination which adversely affect their individual and collective development and depreciate their societal value. Therefore gender advocates seek to correct the imbalances. The question is: where both boys and girls suffer similar abuses, how should gender advocacy be adjusted to accommodate all interests?

    Brigette Metzler · University of South Australia

    Or indeed to add to Philipp's point, there's little discussion about how discrimination against women bears a cost to men as well.  For example, by improving provision of social payments for motherhood, are we also entrenching the male/female work roles?  Do men then automatically miss out because they are not female?  What do men gain by improving equality? More equal access to traditional female roles such as child raising, family caring roles etc?  I am interested in public policy, so my bias is obvious, but I think the debate and discussion needs to focus on both sexes and what can be gained through equality, for both sexes, not just women. 

    hope that helps!

  • Abbas Rahdar added an answer in Superparamagnetism:
    Why do we use Langevin function in superparamagnetism and no Brillouin function ?

    why does use from Langevin function in superparamagnetism and no Brillouin function ?Langevin function is classical limit of Brillouin function.

    Abbas Rahdar · Zabol University

    Explain why ferromagnetism is observed in the second half of the 3dtransition series and not in the first half?

  • Chen Chong added an answer in Pedogenesis:
    How can I realize a 3D representation of soil nutrient distribution by using both ArcInfo and ArcGIS software?

    According to the article of "3D representation of soil distribution: An approach for understanding pedogenesis", I have tried my best to make a figure like Fig.3 under the help of Fig.2 (schematic representation of the 3D approach). But I failed. So more detailed steps are needed for helping me to make a figure (like Fig.3 ) about 3D representation of soil nutrient distribution.

    Available data: (1) topographic map (1:2000); (2) DEM; X, Y and Z of sampling points; (3) horizon thickness (H); (4) the characteristics of each horizon (gravel content, porosity, …).
    For example:
    Sample point        X                  Y               Z         H1   H2 …  G1     G2 …
                1         35623078    3340041   291.53    20   15 … 1.34    0.61…
                2         35623309    3340165   284.88    25   18 … 0.25   0.13…
                3         35623423    3340807   280.13    22   10 … 0.57   0.49…
    Note: H1,H2,…: the thickness of each horizon (A, B,…), cm; G1,G2,…: gravel content of each horizon, %.

    (PS: The more details the better. ……

            Great thanks to everyone who share their answers! )

    Chen Chong · China Agricultural University

    GMS sofeware or SGeMs software can realize 3D representation of different soil properties. I hope that the information can help you. 

  • Andrei Nikonov added an answer in HEPES:
    Where can I order 1x DNA oligonucleotide annealing buffer?

    Specifications: 10mM Tris-HCl, 50mM NaCl, 1mM EDTA, pH 7.5-8.0

    I've tried looking into IDT but their buffers contains HEPES.

    Andrei Nikonov · University of Tartu

    Why don't you prepare it yourself?

    BTW, a better alternative would be (final concentrations):

    10 mM HepesKOH pH~8.0

    20 mM KCl



    IDT use Hepes, because they know what they do and how to do it better than others in their field. The thing is the buffer pH changes with temperature, and for Hepes this change is minimal, whereas for Tris its gigantic.

  • Carciumaru Marin added an answer in Botanical Data:
    Is there anybody who has samples of well identified styrax officinalis?

    We need reliable reference samples which are well identified on a botanical point of view. Commercial resins so-called styrax seems to be related to dammar therefore samples that are really authentified by botanical data are requested for comparision with archaeological resins found on artefacts

    Thanks in advance Best Jacques Connan

    Carciumaru Marin · Valahia University of Târgoviste

    Cher collegue,
    Dans l'analyse de pollen en le Pléistocène supérieur en Roumanie n'a pas été trouve. Je crois qu'en Roumanie il n'y a pas aucune en flore actuelle.

    Prof. Carciumaru

  • Niranjan K. Naik added an answer in Composites:
    Can anyone suggest web links available for hybrid composites?

    What are the current technologies or researches that are undergoing in the area of hybrid composites. How can I find them? What are the different sources that I can improve my search for hybrid composites? 

    Niranjan K. Naik · Indian Institute of Technology Bombay

    Using hybrid composite as a key word, you can get many references through Scopus, Web of Science, and Google etc.

    You can refer to the attached paper.

  • Are you interested in contribute for a topic in Frontiers in Microbiology about microbial metabolism and synthetic biology?

    Looking for contributors in the area of microbial metabolism and synthetic biology for a research topic in Frontiers in Microbiology. Be free to share with your colleagues and partners.


    Elumalai Kasi · University of Madras

    this is joournal?

  • Vineet Kumar added an answer in GIS Application:
    Where can I find data of Remote Sensing and GIS of the Niger Delta?
    1. Currently considering a research work on Niger Delta Region. My focus is application of remote sensing and GIS for environmental assessment. Pollution and waste management systems in my mind to consider including land use types. But I am constrained with how to get the right data for this work. Can someone give me hints on the required data sets and where I can easily access these remote sensing data to start the work.
    Vineet Kumar · Indian Institute of Technology Bombay

    You can download optical RS data (LANDSAT) of your area from http://earthexplorer.usgs.gov/

  • Which chemical can be used instead of polyethyleneimine for generating positive charges on surface of nanoparticles?

    For synthesizing a particular type of metal nanoparticles on the surface of silica nanoparticles I had to use polyethyleneimine to generate positive charges, but the problem is that I didn't have this one and I really want to start to work on synthesis of metal nanoparticles. 

    Can anybody who has worked on this kind of particle help me here ?

    Isaac Ojea Jimenez · European Commission - Joint Research Centre

    You can obtain a higher control in the degree of the functionalization by playing with the different analogues of (3-Aminopropyl)triethoxysilane...i.e. trimethylsilane, methoxydimethylsilane, etc

  • Akira Kanda added an answer in Topology:
    Contrary to views of "flatlanders", the lack of topological features can frustrate the economic development of a region?

    Is there a way to reconcile Starrett's impossibility theorem with von Thunen's ideas in his treatise, The Isolated State?

    Is the complication to a feature- free region (e.g. desert), mainly the difficulties in extracting von Thunen rent?

    Akira Kanda · University of Toronto

    Currency was not meant to be traded for the sake of investment. In the past there was a strong regulation to block this destructive activities. When politics interfere economics, we have what we have now.

  • Can somebody tell me the etymology of the word türk 'turk'?
    The English words, Turkish, Turkic, Turk are derived from the common source 'türk' either directly or through some other language. But I would like to know the etymological source and the meaning of it in the Turkish language.
    Mohammad Ali Salmani Nodoushan · International Journal of Language Studies

    I did an Internet search for you and this was the result:

    Late Middle English: via Old French from Turkish türk; c.1300, from French Turc, from Medieval Latin Turcus, from Byzantine Greek Tourkos, Persian turk, a national name, of unknown origin. Said to mean "strength" in Turkish. Compare Chinese tu-kin, recorded from c.177 B.C.E. as the name of a people living south of the Altai Mountains (identified by some with the Huns). In Persian, turk, in addition to the national name, also could mean "a beautiful youth," "a barbarian," "a robber." In English, the Ottoman sultan was the Grand Turk (late 15c.), and the Turk was used collectively for the Turkish people or for Ottoman power (late 15c.). From 14c. and especially 16c.-18c. Turk could mean "a Muslim," reflecting the Turkish political power's status in the Western mind as the Muslim nation par excellence. Hence Turkery "Islam" (1580s); turn Turk "convert to Islam." Meaning "person of Irish descent" is first recorded 1914 in U.S., apparently originating among Irish-Americans; of unknown origin (Irish torc "boar, hog" has been suggested). Young Turk (1908) was a member of an early 20c. political group in the Ottoman Empire that sought rejuvenation of the Turkish nation. Turkish bath is attested from 1640s; Turkish delight from 1877.

  • Naresh Manickam asked a question in Agarose Gel:
    What are the advantages of Denaturing Gradient Gel Electrophoresis(DGGE) over the conventional Agarose Gel Electrophorosis in the Genomic studies?

     I need to Know the Efficiency of DGGE on the Genomic studies of Fungal mixed culture.

  • Zeyb Rode asked a question in MDP:
    How to fix LINCS warning on MD run while applying dihedral restraints?


    I have a big problem with my protein. For studying the role of one residue in enzyme activity, I have to apply dihedral restraints.

    Therefore, I did all steps and performed the restraints for minimizing energy with emstep =0.01, equilibrating with dt = 0.001 but when

    I went through the production MD and run with dt = 0.001 after 328 ps I got LINCS warning with this error: Bond length not finite.

    I checked every steps and I am sure my system is converged and equilibrated (with using g_energy command) and read mailing list but still I do not know how to fix it.

    I changed dt to 0.0005 but when I run this job on cluster it takes much more than usual. I'll be very thankful if you show me what's wrong could be with my initial system.

    Can anyone help me with this problem?

    I really appreciate it.

    Here is my .mdp file:

    define = -DDISRE

    integrator = md

    tinit = 0

    dt = 0.0005

    nsteps = 5000000

    comm_mode = Linear

    nstcomm = 1

    comm_grps = Protein Non-Protein

    nstxout = 0

    nstvout = 250000

    nstfout = 250000

    nstlog = 100

    nstenergy = 500

    energygrps = System

    nstlist = 1

    ns_type = grid

    pbc = xyz

    rlist = 1

    coulombtype = PME

    rcoulomb = 1

    vdwtype = cut-off

    rvdw = 1

    DispCorr = EnerPres

    fourierspacing = 0.12

    pme_order = 4

    ewald_rtol = 1e-5

    tcoupl = nose-hoover

    tc_grps = Protein Non-Protein

    tau_t = 0.1 0.1

    ref_t = 310 310

    pcoupl = parrinello-rahman

    pcoupltype = isotropic

    tau_p = 2.0

    compressibility = 4.5e-5

    ref_p = 1.0

    gen_vel = no

    constraints = all-bonds

    constraint_algorithm = LINCS

    continuation = yes

    lincs_order = 4

    lincs_iter = 1

    lincs_warnangle = 30

    ;dihedral restraints

    dihre = yes

    dihre_fc = 100

    dihre_tau = 0.0

    nstdihreout = 50

  • Subhash C. Juneja added an answer in Chemistry:
    Are so called "islamic state militants" are really concerned about islam religion or it is just a matter of grabbing oil-rich areas?

    Please provide your opinion

    Subhash C. Juneja · Toronto Western Hospital

    Excellent answer, Roland, 

    We need to be open so that we can learn. Timothy Mcveigh did Oklahoma bombing not on the basis of religion but due to his personal grudge. Why ISIS is doing these activities on the basis of religion.

  • Chethan Sharma added an answer in k-means:
    Assessing quality of k-means clustering?


    There are many criteria which can be used to find the "best" number of clusters for k-means. For example DBclust library in R uses about 30 indices: http://cran.r-project.org/web/packages/NbClust/index.html

    In published papers authors tend to use different methods to assess the quality of the algorithm. So, what are the reasons to choose a particular criterion? Does the result have any significance if using another criterion it may change?

    Chethan Sharma · Christ University, Bangalore

    maybe this will help u 

  • Are You interested in Modeling Problem Process?

    I am trying to derive a formula to express logic or verbal problem solving as a function of relevant knowledge plus experience with the kind of problem plus metacognitive factors in an inverse relationship with "difficult" of the problem. I have a flow diagram about the process and I am interested in formalize it. I think the Rasch Model may be an important inspiration source.

    Neveen Mohamed Hafez · Helwan University


    when you reach to the result, please, publish the research

    really excellent

    wish i could help but i am not good in working with rasch model

  • M.Reza Khoshi added an answer in Surface Morphology:
    How to calculate surface roughness factor from AFM analysis?

    I have analysed membranes through AFM analysis for their surface morphology?

    i want calculate the surface roughness for the membranes>

    In the roughness profile which i got has mean roughness mean roughness highest roughness, Ra, Rz, Rt etc Which one to consider.

    M.Reza Khoshi · Rutgers, The State University of New Jersey

    Dear G. Rambabu

    We normally consider the "image Rq" and the "image Ra" for judging the roughness of the sample.

    Rq is the root mean square average of height deviation taken from the mean image data plane.

    Ra is the arithmetic average of the absolute values of the surface height deviations measured from the mean plane.

  • Herbert Gratzl added an answer in Global Warming:
    Is the green house effect or global warming responsible for climate change?

    What are the main causes of climate change? How do they influence climate change, and in what ratio? 

    Herbert Gratzl · Stiftung Danubius, for ecological education

    @ Bhavika

    Certainly there are local sources for the green house effect and also sinks.

    The increasing number of cattle and other livestock, agriculture are estimated to contribute even more than the whole traffic ( see attachment LivestockClimateChange for further reading and references ). 

    If people want better food, they often prefer more meat, what is not good for climate nor for health. Apart from tradition and taste there are nutritional reasons, which may lead to other choices with more food from plants and not from animals ( my recent short notice/publ.   The vitamin B12 Gap .. /Animal Products . . ) ) .

  • Diet for diabetes type 2 depending on gene analysis?

    what are the SNPs that I can use to form diet for type 2 diabetes depending on gene analysis?

    vitamins or minerals depending of gene polymorphisms ?