60. CONDENSED MATTER: STRUCTURAL, MECHANICAL, AND THERMAL PROPERTIES
61. Structure of solids and liquids; crystallography (for surface, interface, and thin film structure, see section 68)
61.10.-i X-ray diffraction and scattering (for X-ray diffractometers, see 07.85.Jy; for X-ray studies of crystal defects, see 61.72.Dd, Ff)
61.10.Dp Theories of diffraction and scattering
61.10.Eq X-ray scattering (including small-angle scattering)
61.10.Ht X-ray absorption spectroscopy: EXAFS, NEXAFS, XANES, etc.
61.10.Kw X-ray reflectometry (surfaces, interfaces, films)
61.10.Nz X-ray diffraction
61.12.-q Neutron diffraction and scattering
61.12.Bt Theories of diffraction and scattering
61.12.Ex Neutron scattering (including small-angle scattering)
61.12.Ha Neutron reflectometry
61.12.Ld Neutron diffraction
61.14.-x Electron diffraction and scattering (for electron diffractometers, see 07.78.+s)
61.14.Dc Theories of diffraction and scattering
61.14.Hg Low-energy electron diffraction (LEED) and reflection high-energy electron diffraction (RHEED)
61.14.Lj Convergent-beam electron diffraction, selected-area electron diffraction, nanodiffraction
61.14.Nm Electron holography
61.14.Qp X-ray photoelectron diffraction
... ... ...Microscopy of surfaces, interfaces, and thin films, see 68.37.-d
61.18.-j Other methods of structure determination
61.18.Bn Atom, molecule, and ion scattering
61.18.Fs Magnetic resonance techniques; Mossbauer spectroscopy
61.20.-p Structure of liquids
61.20.Gy Theory and models of liquid structure
61.20.Ja Computer simulation of liquid structure
61.20.Lc Time-dependent properties; relaxation (for glass transitions, see 64.70.Pf)
61.20.Ne Structure of simple liquids
61.20.Qg Structure of associated liquids: electrolytes, molten salts, etc.
61.25.-f Studies of specific liquid structures
61.25.Bi Liquid noble gases
61.25.Em Molecular liquids
61.25.Hq Macromolecular and polymer solutions; polymer melts; swelling
61.25.Mv Liquid metals and alloys
61.30.-v Liquid crystals (for phase transitions in liquid crystals, see 64.70.Md; for liquid crystals as dielectric materials, see 77.84.Nh; for liquid crystals as optical materials, see 42.70.Df; for liquid crystal devices, see 42.79.Kt)
61.30.Cz Molecular and microscopic models and theories of liquid crystal structure
61.30.Dk Continuum models and theories of liquid crystal structure
61.30.Eb Experimental determinations of smectic, nematic, cholesteric, and other structures
61.30.Gd Orientational order of liquid crystals; electric and magnetic field effects on order
61.30.Hn Surface phenomena: alignment, anchoring, anchoring transitions, surface-induced layering, surface-induced ordering, wetting, prewetting transitions, and wetting transitions
61.30.Jf Defects in liquid crystals
61.30.Mp Blue phases and other defect-phases
61.30.Pq Microconfined liquid crystals: droplets, cylinders, randomly confined liquid crystals, polymer dispersed liquid crystals, and porous systems
61.30.St Lyotropic phases
61.30.Vx Polymer liquid crystals
61.41.+e Polymers, elastomers, and plastics (see also 81.05.Lg in materials science; for rheology of polymers, see section 83; for polymer reactions and polymerization, see 82.35.-x in physical chemistry and chemical physics)
61.43.-j Disordered solids (see also 81.05.Gc, 81.05.Kf, and 81.05.Rm in materials science; for photoluminescence of disordered solids, see 78.55.Mb and 78.55.Qr)
61.43.Bn Structural modeling: serial-addition models, computer simulation
61.43.Dq Amorphous semiconductors, metals, and alloys
61.43.Er Other amorphous solids
61.43.Fs Glasses
61.43.Gt Powders, porous materials
61.43.Hv Fractals; macroscopic aggregates (including diffusion-limited aggregates)
61.44.-n Semi-periodic solids
61.44.Br Quasicrystals
61.44.Fw Incommensurate crystals
61.46.-w Nanoscale materials (for electronic transport in nanoscale materials, see 73.63.-b)
61.46.Bc Clusters
61.46.Df Nanoparticles
61.46.Fg Nanotubes
61.46.Hk Nanocrystals
61.48.+c Fullerenes and fullerene-related materials (see also 81.05.Tp Fullerenes and related materials in materials science)
61.50.-f Crystalline state
61.50.Ah Theory of crystal structure, crystal symmetry; calculations and modeling
... ... ...Crystal growth, see 81.10.-h
61.50.Ks Crystallographic aspects of phase transformations; pressure effects (see also 81.30.Hd in materials science)
61.50.Lt Crystal binding; cohesive energy
61.50.Nw Crystal stoichiometry
61.66.-f Structure of specific crystalline solids (for surface structure, see 68.35.Bs)
61.66.Bi Elemental solids
61.66.Dk Alloys
61.66.Fn Inorganic compounds
61.66.Hq Organic compounds
... ... ...Quantum crystals, see 67.80.Cx
61.68.+n Crystallographic databases
61.72.-y Defects and impurities in crystals; microstructure (for radiation induced defects, see 61.80.-x; for defects in surfaces, interfaces, and thin films, see 68.35.Dv and 68.55.Ln; see also 85.40.Ry Impurity doping, diffusion, and ion implantation technology)
61.72.Bb Theories and models of crystal defects
61.72.Cc Kinetics of defect formation and annealing
61.72.Dd Experimental determination of defects by diffraction and scattering
61.72.Ff Direct observation of dislocations and other defects (etch pits, decoration, electron microscopy, x-ray topography, etc.)
61.72.Hh Indirect evidence of dislocations and other defects (resistivity, slip, creep, strains, internal friction, EPR, NMR, etc.)
61.72.Ji Point defects (vacancies, interstitials, color centers, etc.) and defect clusters
61.72.Lk Linear defects: dislocations, disclinations
61.72.Mm Grain and twin boundaries
61.72.Nn Stacking faults and other planar or extended defects
61.72.Qq Microscopic defects (voids, inclusions, etc.)
61.72.Ss Impurity concentration, distribution, and gradients (for impurities in thin films, see 68.55.Ln; see also 66.30.Jt Diffusion of impurities)
61.72.Tt Doping and impurity implantation in germanium and silicon
61.72.Vv Doping and impurity implantation in III-V and II-VI semiconductors
61.72.Ww Doping and impurity implantation in other materials
61.72.Yx Interaction between different crystal defects; gettering effect
61.80.-x Physical radiation effects, radiation damage (for photochemical reactions, see 82.50.-m)
... ... ...Radiation treatments, see 81.40.Wx
61.80.Az Theory and models of radiation effects
61.80.Ba Ultraviolet, visible, and infrared radiation effects (including laser radiation)
61.80.Cb X-ray effects
61.80.Ed gamma-ray effects
61.80.Fe Electron and positron radiation effects
61.80.Hg Neutron radiation effects
61.80.Jh Ion radiation effects (for ion implantation, see 61.72.Tt, Vv, Ww)
61.80.Lj Atom and molecule irradiation effects
... ... ...Channeling, blocking, and energy loss of particles, see 61.85.+p
61.82.-d Radiation effects on specific materials
61.82.Bg Metals and alloys
61.82.Fk Semiconductors
61.82.Ms Insulators
61.82.Pv Polymers, organic compounds
61.82.Rx Nanocrystalline materials
61.85.+p Channeling phenomena (blocking, energy loss, etc.)
61.90.+d Other topics in structure of solids and liquids; crystallography (restricted to new topics in section 61)
62. Mechanical and acoustical properties of condensed matter (for nonlinear acoustics of solids, see 43.25.Dc—in acoustics appendix; for mechanical and acoustical properties of interfaces and thin films, see 68.35.Gy, 68.35.Iv, and 68.60.Bs; for mechanical properties related to treatment conditions, see 81.40.Jj, Lm, Np—in material science; for mechanical and acoustical properties of superconductors, see 74.25.Ld; for mechanical and acoustical properties of rocks and minerals, see 91.60.Ba, Dc, and Lj)
62.10.+s Mechanical properties of liquids (for viscosity of liquids, see 66.20.+d)
62.20.-x Mechanical properties of solids
62.20.Dc Elasticity, elastic constants
62.20.Fe Deformation and plasticity (including yield, ductility, and superplasticity) (see also 83.50.-v Deformation and flow in rheology)
62.20.Hg Creep
62.20.Mk Fatigue, brittleness, fracture, and cracks
62.20.Qp Tribology and hardness (see also 46.55.+d Tribology and mechanical contacts in continuum mechanics of solids)
62.25.+g Mechanical properties of nanoscale materials
62.30.+d Mechanical and elastic waves; vibrations (see also 43.40.+s Structural acoustics and vibration; 46.40.-f Vibrations and mechanical waves in continuum mechanics of solids)
62.40.+i Anelasticity, internal friction, stress relaxation, and mechanical resonances (see also 81.40.Jj Elasticity and anelasticity in materials science)
... ... ...Thermomechanical effects, see 65.40.De
... ... ...Magnetomechanical effects, see 75.80.+q
... ... ...Piezoelectric effects, see 77.65.-j
... ... ...Elastooptical effects, see 78.20.Hp
62.50.+p High-pressure and shock wave effects in solids and liquids (for high pressure apparatus and techniques, see 07.35.+k; for shock wave initiated high-pressure chemistry, see 82.40.Fp; for high-pressure behavior of rocks and minerals, see 91.60.Gf; see also 47.40.Nm Shock wave interactions and shock effects in fluid dynamics)
62.60.+v Acoustical properties of liquids (see also 43.35.+d in acoustics)
... ... ...Lattice dynamics, phonons, see section 63
... ... ...Sound waves in fluid dynamics, see 47.35.Rs
... ... ...Second sound in quantum fluids, see 67.40.Pm
62.65.+k Acoustical properties of solids
... ... ...Magnetoacoustic effects, see 72.55.+s and 73.50.Rb
... ... ...Acoustoelectric effects, see 72.50.+b, 73.50.Rb, and 77.65.Dq
... ... ...Acoustooptical effects, see 78.20.Hp
62.80.+f Ultrasonic relaxation (see also 43.35.Fj Ultrasonic relaxation processes in liquids and solids—in acoustics appendix; for ultrasonic attenuation in superconductors, see 74.25.Ld)
62.90.+k Other topics in mechanical and acoustical properties of condensed matter (restricted to new topics in section 62)
63. Lattice dynamics (see also 78.30.-j Infrared and Raman spectra; for surface and interface vibrations, see 68.35.Ja; for adsorbate vibrations, see 68.43.Pq)
63.10.+a General theory
63.20.-e Phonons in crystal lattices (for phonons in superconductors, see 74.25.Kc; see also 43.35.Gk Phonons in crystal lattice, quantum acoustics—in acoustics appendix)
63.20.Dj Phonon states and bands, normal modes, and phonon dispersion
63.20.Kr Phonon-electron and phonon-phonon interactions
63.20.Ls Phonon interactions with other quasiparticles
63.20.Mt Phonon-defect interactions
63.20.Pw Localized modes
63.20.Ry Anharmonic lattice modes
63.22.+m Phonons or vibrational states in low-dimensional structures and nanoscale materials
63.50.+x Vibrational states in disordered systems
63.70.+h Statistical mechanics of lattice vibrations and displacive phase transitions
63.90.+t Other topics in lattice dynamics (restricted to new topics in section 63)
64. Equations of state, phase equilibria, and phase transitions (see also 82.60.-s Chemical thermodynamics)
64.10.+h General theory of equations of state and phase equilibria (see also 05.70.Ce Thermodynamic functions and equations of state in thermodynamics)
64.30.+t Equations of state of specific substances
64.60.-i General studies of phase transitions (see also 63.70.+h Statistical mechanics of lattice vibrations and displacive phase transitions; for critical phenomena in solid surfaces and interfaces, and in magnetism, see 68.35.Rh, and 75.40.-s, respectively)
64.60.Ak Renormalization-group, fractal, and percolation studies of phase transitions (see also 61.43.Hv Fractals; macroscopic aggregates)
64.60.Cn Order-disorder transformations; statistical mechanics of model systems
64.60.Fr Equilibrium properties near critical points, critical exponents
64.60.Ht Dynamic critical phenomena
64.60.Kw Multicritical points
64.60.My Metastable phases
64.60.Qb Nucleation (see also 82.60.Nh Thermodynamics of nucleation in physical chemistry and chemical physics)
64.70.-p Specific phase transitions
64.70.Dv Solid-liquid transitions
64.70.Fx Liquid-vapor transitions
64.70.Hz Solid-vapor transitions
64.70.Ja Liquid-liquid transitions
64.70.Kb Solid-solid transitions (see also 61.50.Ks Crystallographic aspects of phase transformations; pressure effects; 75.30.Kz and 77.80.Bh for magnetic and ferroelectric transitions, respectively; for material science aspects, see 81.30.-t)
64.70.Md Transitions in liquid crystals
64.70.Nd Structural transitions in nanoscale materials
64.70.Pf Glass transitions
64.70.Rh Commensurate-incommensurate transitions
64.75.+g Solubility, segregation, and mixing; phase separation (see also 82.60.Lf Thermodynamics of solutions; 47.51.+a Mixing in fluid dynamics)
64.90.+b Other topics in equations of state, phase equilibria, and phase transitions (restricted to new topics in section 64)
65. Thermal properties of condensed matter (see also section 44 Heat transfer; for thermodynamic properties of quantum fluids and solids, see section 67; for thermal properties of thin films, see 68.60.Dv; for nonelectronic thermal conduction, see 66.60.+a and 66.70.+f; for thermal properties of rocks and minerals, see 91.60.Ki; for thermodynamic properties of superconductors, see 74.25.Bt)
65.20.+w Thermal properties of liquids: heat capacity, thermal expansion, etc.
65.40.-b Thermal properties of crystalline solids (for specific heat of superconductors, see 74.25.Bt; for specific heat of magnetic systems, see 75.40.Cx)
65.40.Ba Heat capacity
65.40.De Thermal expansion; thermomechanical effects
65.40.Gr Entropy and other thermodynamical quantities
65.60.+a Thermal properties of amorphous solids and glasses: heat capacity, thermal expansion, etc.
65.80.+n Thermal properties of small particles, nanocrystals, and nanotubes (see also 82.60.Qr Thermodynamics of nanoparticles in physical chemistry and chemical physics)
65.90.+i Other topics in thermal properties of condensed matter (restricted to new topics in section 65)
66. Transport properties of condensed matter (nonelectronic)
66.10.-x Diffusion and ionic conduction in liquids
66.10.Cb Diffusion and thermal diffusion (for osmosis in biological systems, see 82.39.Wj in physical chemistry)
66.10.Ed Ionic conduction
66.20.+d Viscosity of liquids; diffusive momentum transport
66.30.-h Diffusion in solids (for surface and interface diffusion, see 68.35.Fx)
66.30.Dn Theory of diffusion and ionic conduction in solids
66.30.Fq Self-diffusion in metals, semimetals, and alloys
66.30.Hs Self-diffusion and ionic conduction in nonmetals
66.30.Jt Diffusion of impurities
66.30.Lw Diffusion of other defects
66.30.Ny Chemical interdiffusion; diffusion barriers
66.30.Pa Diffusion in nanoscale solids
66.30.Qa Electromigration
66.30.Xj Thermal diffusivity
66.35.+a Quantum tunneling of defects
66.60.+a Thermal conduction in nonmetallic liquids (for thermal conduction in liquid metals, see 72.15.Cz)
66.70.+f Nonelectronic thermal conduction and heat-pulse propagation in solids; thermal waves (for thermal conduction in metals and alloys, see 72.15.Cz and 72.15.Eb)
66.90.+r Other topics in nonelectronic transport properties of condensed matter (restricted to new topics in section 66)
67. Quantum fluids and solids; liquid and solid helium (see also 05.30.-d Quantum statistical mechanics; for cryogenics, refrigerators, low-temperature detectors, and other low temperature equipment, see 07.20.Mc; see also 47.37.+q Hydrodynamic aspects of superfluidity; quantum fluids — in fluid dynamics)
67.20.+k Quantum effects on the structure and dynamics of nondegenerate fluids (e.g., normal phase liquid 4He)
67.40.-w Boson degeneracy and superfluidity of 4He
67.40.Bz Phenomenology and two-fluid models
67.40.Db Quantum statistical theory; ground state, elementary excitations
67.40.Fd Dynamics of relaxation phenomena
67.40.Hf Hydrodynamics in specific geometries, flow in narrow channels
67.40.Jg Ions in liquid 4He
67.40.Kh Thermodynamic properties
67.40.Mj First sound
67.40.Pm Transport processes, second and other sounds, and thermal counterflow; Kapitza resistance
67.40.Rp Films and weak link transport
67.40.Vs Vortices and turbulence
67.40.Yv Impurities and other defects
67.55.-s Normal phase of liquid 3He
67.55.Cx Thermodynamic properties
67.55.Fa Hydrodynamics
67.55.Hc Transport properties
67.55.Ig Ions in normal liquid 3He
67.55.Jd Collective modes
67.55.Lf Impurities
67.57.-z Superfluid phase of liquid 3He
67.57.Bc Thermodynamic properties
67.57.De Superflow and hydrodynamics
67.57.Fg Textures and vortices
67.57.Gh Ions in superfluid 3He
67.57.Hi Transport properties
67.57.Jj Collective modes
67.57.Lm Spin dynamics
67.57.Np Behavior near interfaces
67.57.Pq Impurities
67.60.-g Mixed systems; liquid 3He, 4He mixtures
67.60.Dm HeI–3He
67.60.Fp HeII-3He
67.60.Hr Dilute superfluid 3He in He II
67.60.Js Ions in liquid 3He–4He mixtures
67.65.+z Spin-polarized hydrogen and helium
67.70.+n Films (including physical adsorption)
67.80.-s Solid helium and related quantum crystals
67.80.Cx Structure, lattice dynamics, and sound propagation
67.80.Gb Thermal properties
67.80.Jd Magnetic properties and nuclear magnetic resonance
67.80.Mg Defects, impurities, and diffusion
67.90.+z Other topics in quantum fluids and solids; liquid and solid helium (restricted to new topics in section 67)
68. Surfaces and interfaces; thin films and low-dimensional systems (structure and nonelectronic properties) (for surface and interface chemistry, see 82.65.+r, for surface magnetism, see 75.70.Rf)
68.03.-g Gas-liquid and vacuum-liquid interfaces
68.03.Cd Surface tension and related phenomena
68.03.Fg Evaporation and condensation
68.03.Hj Structure: measurements and simulations
68.03.Kn Dynamics (capillary waves)
68.05.-n Liquid-liquid interfaces
68.05.Cf Structure: measurements and simulations
68.05.Gh Interfacial properties of microemulsions
68.08.-p Liquid-solid interfaces
68.08.Bc Wetting
68.08.De Structure: measurements and simulations
... ... ...Crystal growth, biomineralization, see 81.10.Dn, Fq
68.15.+e Liquid thin films
68.18.-g Langmuir-Blodgett films on liquids (for L-B films on solids, see 68.47.Pe)
68.18.Fg Structure: measurements and simulations
68.18.Jk Phase transitions
68.35.-p Solid surfaces and solid-solid interfaces: Structure and energetics
68.35.Af Atomic scale friction
68.35.Bs Structure of clean surfaces (reconstruction)
68.35.Ct Interface structure and roughness
68.35.Dv Composition, segregation; defects and impurities
68.35.Fx Diffusion; interface formation (see also 66.30.-h Diffusion in solids, for diffusion of adsorbates, see 68.43.Jk)
68.35.Gy Mechanical properties; surface strains
68.35.Iv Acoustical properties
68.35.Ja Surface and interface dynamics and vibrations
... ... ...Solid-solid interfaces: transport and optical properties, see 73.40.-c and 78.20.-e respectively
68.35.Md Surface thermodynamics, surface energies (see also 05.70.Np Interface and surface thermodynamics in statistical physics, thermodynamics and nonlinear dynamical systems)
68.35.Np Adhesion (for polymer adhesion, see 82.35.Gh)
68.35.Rh Phase transitions and critical phenomena
68.37.-d Microscopy of surfaces, interfaces, and thin films
68.37.Ef Scanning tunneling microscopy (including chemistry induced with STM)
68.37.Hk Scanning electron microscopy (SEM) (including EBIC)
68.37.Lp Transmission electron microscopy (TEM) (including STEM, HRTEM, etc.)
68.37.Nq Low energy electron microscopy (LEEM)
68.37.Ps Atomic force microscopy (AFM)
68.37.Rt Magnetic force microscopy (MFM)
68.37.Tj Acoustic force microscopy
68.37.Uv Near-field scanning microscopy and spectroscopy
68.37.Vj Field emission and field-ion microscopy
68.37.Xy Scanning Auger microscopy, photoelectron microscopy
68.37.Yz X-ray microscopy
68.43.-h Chemisorption/physisorption: adsorbates on surfaces
68.43.Bc Ab initio calculations of adsorbate structure and reactions (for electronic structure of adsorbates, see 73.20.Hb; for adsorbate reactions, see also 82.65.+r Surface and interface chemistry; heterogeneous catalysis at surfaces)
68.43.De Statistical mechanics of adsorbates
68.43.Fg Adsorbate structure (binding sites, geometry)
68.43.Hn Structure of assemblies of adsorbates (two- and three-dimensional clustering)
68.43.Jk Diffusion of adsorbates, kinetics of coarsening and aggregation
68.43.Mn Adsorption/desorption kinetics
68.43.Pq Adsorbate vibrations
68.43.Rs Electron stimulated desorption
68.43.Tj Photon stimulated desorption
68.43.Vx Thermal desorption
68.47.-b Solid-gas/vacuum interfaces: types of surfaces
68.47.De Metallic surfaces
68.47.Fg Semiconductor surfaces
68.47.Gh Oxide surfaces
68.47.Jn Clusters on oxide surfaces
68.47.Mn Polymer surfaces
68.47.Pe Langmuir-Blodgett films on solids; polymers on surfaces; biological molecules on surfaces
68.49.-h Surface characterization by particle-surface scattering (see also 34.50.Dy Interactions of atoms and molecules with surfaces; photon and electron emission; neutralization of ions in atomic and molecular collision processes and interactions)
68.49.Bc Atom scattering from surfaces (diffraction and energy transfer)
68.49.Df Molecule scattering from surfaces (energy transfer, resonances, trapping)
68.49.Fg Cluster scattering from surfaces
68.49.Jk Electron scattering from surfaces
68.49.Sf Ion scattering from surfaces (charge transfer, sputtering, SIMS)
68.49.Uv X-ray standing waves
... ... ...Surface and interface electron states, see 73.20.-r
... ... ...Electronic structure of adsorbates, see 73.20.Hb
... ... ...Vibrational spectroscopy (IR, Raman, ATR), see 78.30.-j
... ... ...Electron spectroscopy (EELS, Auger, metastable quenching spectroscopy) see 79.20.-m
... ... ...Photoelectron spectroscopy (XPS and UPS), see 79.60.-i
... ... ...Nonlinear spectroscopy (second harmonic, sum frequency generation, etc.), see 42.65.Ky
... ... ...Electron diffraction (LEED, RHEED), see 61.14.-x
... ... ...Surface enhanced spectroscopy, plasmons, see 73.20.Mf
... ... ...Near-field scanning microscopy and spectroscopy, see 68.37.Uv
68.55.-a Thin film structure and morphology (for methods of thin film deposition, film growth and epitaxy, see 81.15.-z)
68.55.Ac Nucleation and growth: microscopic aspects
68.55.Jk Structure and morphology; thickness; crystalline orientation and texture
68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc. (for diffusion of impurities, see 66.30.Jt)
68.55.Nq Composition and phase identification
68.60.-p Physical properties of thin films, nonelectronic
68.60.Bs Mechanical and acoustical properties
68.60.Dv Thermal stability; thermal effects
68.60.Wm Other nonelectronic physical properties
68.65.-k Low-dimensional, mesoscopic, and nanoscale systems: structure and nonelectronic properties (for structure of nanoscale materials, see 61.46.-w; for magnetic properties of interfaces, see 75.70.Cn; for superconducting properties, see 74.78.-w; for optical properties, see 78.67.-n; for transport properties, see 73.63.-b)
... ... ...Growth of low-dimensional structures, see 81.16.-c
68.65.Ac Multilayers
68.65.Cd Superlattices
68.65.Fg Quantum wells
68.65.Hb Quantum dots
68.65.La Quantum wires
68.70.+w Whiskers and dendrites (growth, structure, and nonelectronic properties)
68.90.+g Other topics in structure, and nonelectronic properties of surfaces and interfaces; thin films and low-dimensional structures (restricted to new topics in section 68)